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Kevin Chen

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University of Missouri - St. Louis

Steven J. Miller

Williams College

University of the Philippines Diliman

Kathryn LaFevers Evans, Three Eagles

Pacifica Graduate Institute

Rice University

Christian Frevel

Ruhr-Universität Bochum

Collège de France

John Keith Hart

University of Cambridge

Princeton University

Nikos Mantzakouras

National & Kapodistrian University of Athens

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Papers by Kevin Chen

CCAAT/Enhancer-Binding Protein β (Nuclear Factor for Interleukin 6) Transactivates the HumanMDR1 Gene by Interaction with an Inverted CCAAT Box in Human Cancer Cells

Molecular Pharmacology, 2004

We investigated the mechanisms of MDR1 gene activation by CCAAT/enhancer binding protein ␤ (C/EBP... more We investigated the mechanisms of MDR1 gene activation by CCAAT/enhancer binding protein ␤ (C/EBP␤, or nuclear factor for interleukin 6) in human cancer cells. Transfection of the breast cancer cell line MCF-7 and its doxorubicin-selected variant MCF-7/ADR by either C/EBP␤ or C/EBP␤-LIP (a dominant-negative form of C/EBP␤) confirmed their roles in the activation or repression of the endogenous, chromosomally embedded MDR1 gene. Cotransfection experiments with promoter constructs revealed a C/EBP␤ interaction on the MDR1 promoter via the region within Ϫ128 to Ϫ75. Deletions within the putative AP-1 box (Ϫ123 to Ϫ111) increased MDR1 promoter activity when stimulated by C/EBP␤, suggesting that the AP-1 site negatively regulates MDR1 activation by C/EBP␤. Mutations within the inverted CCAAT box (Y box) (Ϫ82 to Ϫ73) abolished the C/EBP␤-stimulated MDR1 promoter activity, indicating that the Y box is required for MDR1 activation by C/EBP␤. Chromatin immunoprecipitation (ChIP) revealed that C/EBP␤ precipitates a transcription complex containing C/EBP␤, the MDR1 promoter sequences (Ϫ250 to ϩ54), and the hBrm protein. In conclusion, alteration of expression or function of C/EBP␤ plays an important role in MDR1 gene regulation. C/EBP␤ activates the endogenous MDR1 gene of MCF-7 cells, and this activation was associated with a novel C/EBP␤ interaction region within the proximal MDR1 promoter (Ϫ128 to Ϫ75). The mechanisms of MDR1 activation by C/EBP␤ include C/EBP␤ binding of the chromatin of the MDR1 gene and interactions of C/EBP␤ with the Y box and Y boxassociated proteins.

The empirical size of trained neural networks

Cornell University - arXiv, Nov 28, 2016

ReLU neural networks define piecewise linear functions of their inputs. However, initializing and... more ReLU neural networks define piecewise linear functions of their inputs. However, initializing and training a neural network is very different from fitting a linear spline. In this paper, we expand empirically upon previous theoretical work to demonstrate features of trained neural networks. Standard network initialization and training produce networks vastly simpler than a naive parameter count would suggest and can impart odd features to the trained network. However, we also show the forced simplicity is beneficial and, indeed, critical for the wide success of these networks.

A step-gate-oxide SOI MOSFET for RF power amplifiers in short- and medium-range wireless applications

2003 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2003. Digest of Papers.

ABSTRACT

Knots in random neural networks

ArXiv, 2018

The weights of a neural network are typically initialized at random, and one can think of the fun... more The weights of a neural network are typically initialized at random, and one can think of the functions produced by such a network as having been generated by a prior over some function space. Studying random networks, then, is useful for a Bayesian understanding of the network evolution in early stages of training. In particular, one can investigate why neural networks with huge numbers of parameters do not immediately overfit. We analyze the properties of random scalar-input feed-forward rectified linear unit architectures, which are random linear splines. With weights and biases sampled from certain common distributions, empirical tests show that the number of knots in the spline produced by the network is equal to the number of neurons, to very close approximation. We describe our progress towards a completely analytic explanation of this phenomenon. In particular, we show that random single-layer neural networks are equivalent to integrated random walks with variable step sizes...

Adult and Cancer Stem Cells: Perspectives on Autophagic Fate Determinations and Molecular Intervention

Targeting Autophagy in Cancer Therapy, 2016

Autophagy is a highly conserved mechanism for the maintenance of cellular homeostasis and functio... more Autophagy is a highly conserved mechanism for the maintenance of cellular homeostasis and functionality in pluripotent stem cells, adult stem cells, and normal somatic cells. Cytoprotective roles of autophagy are essential for eliminating damaged subcellular organelles like mitochondria and protein aggregates, thereby reducing reactive oxygen species (ROS) levels and promoting normal or cancer cell survival. We clarify multiple autophagic inducers, default pathway sensors, and regulators in various stages of stem cells. Of note, with autophagy deficiency, there are two major autophagy-associated outcomes, including pro-autophagic cell survival and death. Clearly, the fates of autophagic determination are tightly regulated by their microenvironments, cell types, and the interplay among multiple cell death machineries related to autophagy, apoptosis, and necrosis. Based on the above fundamental autophagic differences among various cell types, we propose a new concept, balanced autophagy, which sheds light on an equilibrium state between pro-autophagic cell survival and death. We further suggest new strategies targeting therapeutic-resistant cancer stem cells that emphasize the modulatory effects of pro-autophagic cell death in intractable cancer cells.

The Upper Bound on Knots in Neural Networks

ArXiv, 2016

Neural networks with rectified linear unit activations are essentially multivariate linear spline... more Neural networks with rectified linear unit activations are essentially multivariate linear splines. As such, one of many ways to measure the "complexity" or "expressivity" of a neural network is to count the number of knots in the spline model. We study the number of knots in fully-connected feedforward neural networks with rectified linear unit activation functions. We intentionally keep the neural networks very simple, so as to make theoretical analyses more approachable. An induction on the number of layers $l$ reveals a tight upper bound on the number of knots in $\mathbb{R} \to \mathbb{R}^p$ deep neural networks. With $n_i \gg 1$ neurons in layer $i = 1, \dots, l$, the upper bound is approximately $n_1 \dots n_l$. We then show that the exact upper bound is tight, and we demonstrate the upper bound with an example. The purpose of these analyses is to pave a path for understanding the behavior of general $\mathbb{R}^q \to \mathbb{R}^p$ neural networks.

Effect of Glucocorticoids on Athletic Performance: A Systematic Review and Meta-Analysis

Clinical Journal of Sport Medicine, 2021

Supplemental Digital Content is Available in the Text. Objective: To determine the effects of glu... more Supplemental Digital Content is Available in the Text. Objective: To determine the effects of glucocorticoids in enhancing athletic performance. Design: At least 2 independent reviewers conducted study selection and extracted demographic and outcome data. Relevant outcomes were stratified by administration time frame and the specific type of drug used. Study quality was assessed using the Cochrane Risk-of-Bias tool and the Cochrane Grading of Recommendations Assessment Development and Education scale. Where appropriate, meta-analyses were performed. Data sources: Embase, MEDLINE, and SPORTDiscus were searched from their beginning to April 2020. Participants: Participants of any sex and training status aged 18 to 65 years were included. Interventions and Main Outcome Measures: Any type of published randomized controlled trial (RCT) that examined any enhancement in sport as well as aerobic, anaerobic, or body compositional parameters for glucocorticoids compared with placebo. Results: There is low-to-moderate evidence suggesting that the administration of glucocorticoids may be more beneficial than placebo in enhancing athletic performance. short-term administration of glucocorticoids significantly improved time to exhaustion, maximal force, and total distance travelled. By contrast, acute administration of glucocorticoids predominantly yielded no changes to athletic performance, except for reductions in total work and maximal power output. Conclusions: Although there is evidence suggesting glucocorticoids have ergogenic effects, these improvements may differ depending on the specific type of drug, dose, and the administration time frame and are also limited by small sample sizes. Therefore, there is a need for large, high-quality RCTs as this may influence future doping policy and athlete care.

Rate Your Addiction Treatment Facility: Exploring the Quality Chasm Online

Journal of General Internal Medicine, 2020

Erratum to: Adult and Cancer Stem Cells: Perspectives on Autophagic Fate Determinations and Molecular Intervention

Current Cancer Research, 2016

Analysis of the Pharmacological and Molecular Heterogeneity of I2-Imidazoline-Binding Proteins using Monoamine Oxidase-Deficient Mouse Models

Molecular Pharmacology, 2000

The I 2 subgroup of imidazoline-binding sites was identified as monoamine oxidases (MAOs), but it... more The I 2 subgroup of imidazoline-binding sites was identified as monoamine oxidases (MAOs), but it is unclear whether there are I 2-binding sites located on proteins distinct from MAOs. To address this issue, we characterized I 2-binding proteins in liver and brain of wild-type and MAO A-and MAO B-deficient mice. I 2-binding sites were identified using [ 3 H]idazoxan and the photoaffinity adduct 2-[3-azido-4-[ 125 I]iodophenoxyl]methylimidazoline ([ 125 I]AZIPI). [ 3 H]Idazoxan labeled binding sites with ligand recognition properties typical of I 2 sites in both brain and liver of wild-type mice. High-affinity, specific [ 3 H]idazoxan binding were not altered in MAO A knockout (KO) mice. In contrast, [ 3 H]idazoxan binding was completely abolished in both liver and brain of MAO B KO mice. In wild-type mice, [ 125 I]AZIPI ABBREVIATIONS: I 2 BS, I 2-imidazoline-binding sites; MAO, monoamine oxidase; [ 125 I]AZIPI, 2-[3-azido-4-[ 125 I]iodophenoxyl]methyl imidazoline; KO, knockout.

Bidirectional promoter of human monoamine oxidase A (MAO A) controlled by transcription factor Sp1

The Journal of Neuroscience, 1994

We thank Joseuh Grimsbv for the ureliminarv Northern analvsis in detectine reverse transcripts an... more

Comparing medical, dental, and nursing students' preparedness to address lesbian, gay, bisexual, transgender, and queer health

PloS one, 2018

Lesbian, gay, bisexual, transgender, and queer (LGBTQ) populations face multiple health dispariti... more Lesbian, gay, bisexual, transgender, and queer (LGBTQ) populations face multiple health disparities including barriers to healthcare. Few studies have examined healthcare trainees' perceptions of their preparedness to care for LGBTQ populations and none have compared perceptions of training across medicine, dental medicine, and nursing. We aimed to understand variations across disciplines in LGBTQ health by assessing medical, dental, and nursing students' perceptions of preparedness across three domains: comfort levels, attitudes, and formal training. We developed a 12-item survey with an interprofessional panel of LGBTQ students from the schools of medicine, dental medicine, and nursing at a top-tier private university in the United States. Any student enrolled full time in any of the three schools were eligible to respond. We performed descriptive statistical analyses and examined patterns in responses using Kruskal-Wallis tests and an ordered logistic regression model. 1,...

Advancing precision medicine with personalized drug screening

Drug discovery today, Jan 17, 2018

Personalized drug screening (PDS) of approved drug libraries enables rapid development of specifi... more Personalized drug screening (PDS) of approved drug libraries enables rapid development of specific small-molecule therapies for individual patients. With a multidisciplinary team including clinicians, researchers, ethicists, informaticians and regulatory professionals, patient treatment can be optimized with greater efficacy and fewer adverse effects by using PDS as an approach to find remedies. In addition, PDS has the potential to rapidly identify therapeutics for a patient suffering from a disease without an existing therapy. From cancer to bacterial infections, we review specific maladies addressed with PDS campaigns. We predict that PDS combined with personal genomic analyses will contribute to the development of future precision medicine endeavors.

Early aseptic loosening of the Tritanium primary acetabular component with screw fixation

Arthroplasty today, 2018

Ultraporous acetabular components were developed to improve osseointegration and fit for increase... more Ultraporous acetabular components were developed to improve osseointegration and fit for increased longevity and better outcomes after total hip arthroplasty. There is a paucity of literature detailing this acetabular component's clinical performance, with even less detailing those with screw fixation. We identify 5 patients at our institution who underwent revision total hip arthroplasty for early aseptic acetabular cup loosening of an ultraporous acetabular component known as the Tritanium primary cup with secondary screw fixation. They all presented with groin and hip pain after index surgery and underwent follow-up radiographic examination consistent with component loosening requiring revision surgery. This case series reports on the risk of early acetabular cup loosening and its associated clinical presentation, workup, and surgical management in patients with the Tritanium primary cup augmented with screws.

ANATOMICAL AND FUNCTIONAL TESTING IN DIABETIC PATIENTS WITHOUT RETINOPATHY: Results of Optical Coherence Tomography Angiography and Visual Acuity Under Varying Contrast and Luminance Conditions

Retina (Philadelphia, Pa.), Jan 13, 2018

To assess early retinal microvascular and functional changes in diabetic patients without clinica... more To assess early retinal microvascular and functional changes in diabetic patients without clinical evidence of diabetic retinopathy with optical coherence tomography angiography and central visual analyzer. This was an observational case-control study of diabetic patients without diabetic retinopathy and nondiabetic controls. Patients underwent optical coherence tomography angiography imaging and visual acuity testing using the central visual analyzer. The foveal avascular zone area and the capillary density in the superficial and deep capillary plexuses were measured manually by a masked grader. Sixty eyes from 35 diabetic patients were included in the study group, and 45 eyes from 31 nondiabetic patients were included in the control group. The foveal avascular zone area was not significantly different between the diabetic group and controls (both P > 0.05). The mean capillary density in the deep capillary plexus was significantly lower in diabetic eyes compared with control eye...

Resolution, Depth of Field, and Physician Satisfaction During Digitally Assisted Vitreoretinal Surgery

Retina (Philadelphia, Pa.), Jan 27, 2018

To evaluate depth of field, lateral resolution, and image quality of a heads-up 3D visualization ... more To evaluate depth of field, lateral resolution, and image quality of a heads-up 3D visualization system for vitreoretinal surgery using physician survey and optical measurement outcomes. Depth of field and lateral resolution were compared between the standard ocular viewing system and the digital 3D system at ×5, ×13, and ×18 magnification by 6 retinal surgeons. Optical techniques were used as well as a survey of surgeon impression. Surgeon impression surveys were performed after 6 weeks of surgical use of the device. Physician questionnaire survey scores for depth of field at high magnification were better for the digital 3D system and equivalent for all other categories. Measured lateral resolution was 36.7 mm and 16.6 mm at ×5 magnification (P < 0.001), 14.3 mm and 6.4 mm at ×13 magnification (P < 0.001), and 9.8 mm and 4.2 mm (P < 0.001) at ×18 magnification for the digital 3D and oculars, respectively. Measured depth of field was 4.00 mm and 6.78 mm at ×5 magnification...

$Research paper thumbnail of {"__content__"=>"Interface Engineering of Monolayer MoS/GaN Hybrid Heterostructure: Modified Band Alignment for Photocatalytic Water Splitting Application by Nitridation Treatment.", "sub"=>{"__content__"=>"2"}}$

{"__content__"=>"Interface Engineering of Monolayer MoS/GaN Hybrid Heterostructure: Modified Band Alignment for Photocatalytic Water Splitting Application by Nitridation Treatment.", "sub"=>{"__content__"=>"2"}}

ACS applied materials & interfaces, Jan 14, 2018

Interface engineering is a key strategy to deal with the two-dimensional (2D)/three-dimensional (... more Interface engineering is a key strategy to deal with the two-dimensional (2D)/three-dimensional (3D) hybrid heterostructure, since the properties of this atomic-layer-thick 2D material can easily be impacted by the substrate environment. In this work, the structural, electronic, and optical properties of the 2D/3D heterostructure of monolayer MoS on wurtzite GaN surface without and with nitridation interfacial layer are systematically investigated by first-principles calculation and experimental analysis. The nitridation interfacial layer can be introduced into the 2D/3D heterostructure by remote N plasma treatment to GaN sample surface prior to stacking monolayer MoS on top. The calculation results reveal that the 2D/3D integrated heterostructure is energetically favorable with a negative formation energy. Both interfaces demonstrate indirect band gap, which is a benefit for longer lifetime of the photoexcited carriers. Meanwhile, the conduction band edge and valence band edge of t...

$Research paper thumbnail of {"__content__"=>"In Situ Resonant Raman Spectroscopy to Monitor the Surface Functionalization of MoS and WSe for High-k Integration: A First-Principles Study.", "sub"=>[{"__content__"=>"2"}, {"__content__"=>"2"}]}$

{"__content__"=>"In Situ Resonant Raman Spectroscopy to Monitor the Surface Functionalization of MoS and WSe for High-k Integration: A First-Principles Study.", "sub"=>[{"__content__"=>"2"}, {"__content__"=>"2"}]}

Langmuir : the ACS journal of surfaces and colloids, Feb 27, 2018

Surface functionalization of the dangling-bond-free MoS, WSe, and other TMDs (transition metal di... more Surface functionalization of the dangling-bond-free MoS, WSe, and other TMDs (transition metal dichalcogenides) is of large practical importance, for example, in providing nucleation sites for the subsequent high-k dielectric integration. Of the surface functionalization methods, the reversible O or N atom adsorption on top of the chalcogen atoms is most promising. However, hazards such as severe oxidation or nitridation persist when the adsorption coverage is high. An in situ characterization technique, which can be integrated with the surface functionalization and dielectric deposition chamber, becomes valuable to enable the real-time monitoring of surface adsorption conditions. Raman spectroscopy, as a nondestructive characterization method without vacuum requirement, is a strong candidate. By utilizing first-principles calculations, Raman spectra of single-layer MoS and WSe with various O/N adsorption coverages are studied. The calculations suggest that the low-coverage O/N adso...

Irrigation and Debridement for Early Periprosthetic Knee Infection: Is It Effective?

The Journal of arthroplasty, Jun 9, 2018

Irrigation and debridement (I&D) is performed for early management of periprosthetic joint infect... more Irrigation and debridement (I&D) is performed for early management of periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). Symptom reporting is a subjective measure and may miss direct management of PJI. Utilizing an objective time interval from index procedure to I&D may better inform treatment decisions. From 2009 to 2017, retrospective review was performed of 55 knee PJI cases at our institution. All patients underwent polyethylene liner exchange and I&D for PJI. Patients were stratified by time from index procedure to I&D (≤2 weeks, >2 weeks). Success was defined as eradication of infection and resolution of presenting symptoms. Failed cases required subsequent procedures due to infection. Average follow-up time after index TKA was 2.5 years. Among patients with I&D within 2 weeks of index TXA, 14 patients (82%) were successfully treated while 3 (18%) had infection recurrence. These outcomes were significantly improved compared to patients with I&D af...

Respiratory Synchronized Versus Intermittent Pneumatic Compression in Prevention of Venous Thromboembolism After Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

The Orthopedic clinics of North America, 2018

The objective of this study was to evaluate the efficacy of respiratory synchronized compression ... more The objective of this study was to evaluate the efficacy of respiratory synchronized compression devices (RSCDs) versus nonsynchronized intermittent pneumatic compression devices (NSIPCDs) in preventing venous thromboembolism (VTE) after total joint arthroplasty. A systematic literature review was conducted. Data regarding surgical procedure, deep vein thrombosis, pulmonary embolism, mortality, and adverse events were abstracted. Compared with control groups, the risk ratio of deep vein thrombosis development was 0.51 with NSIPCDs and 0.47 with RSCDs. This review demonstrates that RSCDs may be marginally more effective at preventing VTE events than NSIPCDs. Furthermore, the addition of mechanical prophylaxis to any chemoprophylactic regimen increases VTE prevention.

CCAAT/Enhancer-Binding Protein β (Nuclear Factor for Interleukin 6) Transactivates the HumanMDR1 Gene by Interaction with an Inverted CCAAT Box in Human Cancer Cells

Molecular Pharmacology, 2004

We investigated the mechanisms of MDR1 gene activation by CCAAT/enhancer binding protein ␤ (C/EBP... more We investigated the mechanisms of MDR1 gene activation by CCAAT/enhancer binding protein ␤ (C/EBP␤, or nuclear factor for interleukin 6) in human cancer cells. Transfection of the breast cancer cell line MCF-7 and its doxorubicin-selected variant MCF-7/ADR by either C/EBP␤ or C/EBP␤-LIP (a dominant-negative form of C/EBP␤) confirmed their roles in the activation or repression of the endogenous, chromosomally embedded MDR1 gene. Cotransfection experiments with promoter constructs revealed a C/EBP␤ interaction on the MDR1 promoter via the region within Ϫ128 to Ϫ75. Deletions within the putative AP-1 box (Ϫ123 to Ϫ111) increased MDR1 promoter activity when stimulated by C/EBP␤, suggesting that the AP-1 site negatively regulates MDR1 activation by C/EBP␤. Mutations within the inverted CCAAT box (Y box) (Ϫ82 to Ϫ73) abolished the C/EBP␤-stimulated MDR1 promoter activity, indicating that the Y box is required for MDR1 activation by C/EBP␤. Chromatin immunoprecipitation (ChIP) revealed that C/EBP␤ precipitates a transcription complex containing C/EBP␤, the MDR1 promoter sequences (Ϫ250 to ϩ54), and the hBrm protein. In conclusion, alteration of expression or function of C/EBP␤ plays an important role in MDR1 gene regulation. C/EBP␤ activates the endogenous MDR1 gene of MCF-7 cells, and this activation was associated with a novel C/EBP␤ interaction region within the proximal MDR1 promoter (Ϫ128 to Ϫ75). The mechanisms of MDR1 activation by C/EBP␤ include C/EBP␤ binding of the chromatin of the MDR1 gene and interactions of C/EBP␤ with the Y box and Y boxassociated proteins.

The empirical size of trained neural networks

Cornell University - arXiv, Nov 28, 2016

ReLU neural networks define piecewise linear functions of their inputs. However, initializing and... more ReLU neural networks define piecewise linear functions of their inputs. However, initializing and training a neural network is very different from fitting a linear spline. In this paper, we expand empirically upon previous theoretical work to demonstrate features of trained neural networks. Standard network initialization and training produce networks vastly simpler than a naive parameter count would suggest and can impart odd features to the trained network. However, we also show the forced simplicity is beneficial and, indeed, critical for the wide success of these networks.

A step-gate-oxide SOI MOSFET for RF power amplifiers in short- and medium-range wireless applications

2003 Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2003. Digest of Papers.

ABSTRACT

Knots in random neural networks

ArXiv, 2018

The weights of a neural network are typically initialized at random, and one can think of the fun... more The weights of a neural network are typically initialized at random, and one can think of the functions produced by such a network as having been generated by a prior over some function space. Studying random networks, then, is useful for a Bayesian understanding of the network evolution in early stages of training. In particular, one can investigate why neural networks with huge numbers of parameters do not immediately overfit. We analyze the properties of random scalar-input feed-forward rectified linear unit architectures, which are random linear splines. With weights and biases sampled from certain common distributions, empirical tests show that the number of knots in the spline produced by the network is equal to the number of neurons, to very close approximation. We describe our progress towards a completely analytic explanation of this phenomenon. In particular, we show that random single-layer neural networks are equivalent to integrated random walks with variable step sizes...

Adult and Cancer Stem Cells: Perspectives on Autophagic Fate Determinations and Molecular Intervention

Targeting Autophagy in Cancer Therapy, 2016

Autophagy is a highly conserved mechanism for the maintenance of cellular homeostasis and functio... more Autophagy is a highly conserved mechanism for the maintenance of cellular homeostasis and functionality in pluripotent stem cells, adult stem cells, and normal somatic cells. Cytoprotective roles of autophagy are essential for eliminating damaged subcellular organelles like mitochondria and protein aggregates, thereby reducing reactive oxygen species (ROS) levels and promoting normal or cancer cell survival. We clarify multiple autophagic inducers, default pathway sensors, and regulators in various stages of stem cells. Of note, with autophagy deficiency, there are two major autophagy-associated outcomes, including pro-autophagic cell survival and death. Clearly, the fates of autophagic determination are tightly regulated by their microenvironments, cell types, and the interplay among multiple cell death machineries related to autophagy, apoptosis, and necrosis. Based on the above fundamental autophagic differences among various cell types, we propose a new concept, balanced autophagy, which sheds light on an equilibrium state between pro-autophagic cell survival and death. We further suggest new strategies targeting therapeutic-resistant cancer stem cells that emphasize the modulatory effects of pro-autophagic cell death in intractable cancer cells.

The Upper Bound on Knots in Neural Networks

ArXiv, 2016

Neural networks with rectified linear unit activations are essentially multivariate linear spline... more Neural networks with rectified linear unit activations are essentially multivariate linear splines. As such, one of many ways to measure the "complexity" or "expressivity" of a neural network is to count the number of knots in the spline model. We study the number of knots in fully-connected feedforward neural networks with rectified linear unit activation functions. We intentionally keep the neural networks very simple, so as to make theoretical analyses more approachable. An induction on the number of layers $l$ reveals a tight upper bound on the number of knots in $\mathbb{R} \to \mathbb{R}^p$ deep neural networks. With $n_i \gg 1$ neurons in layer $i = 1, \dots, l$, the upper bound is approximately $n_1 \dots n_l$. We then show that the exact upper bound is tight, and we demonstrate the upper bound with an example. The purpose of these analyses is to pave a path for understanding the behavior of general $\mathbb{R}^q \to \mathbb{R}^p$ neural networks.

Effect of Glucocorticoids on Athletic Performance: A Systematic Review and Meta-Analysis

Clinical Journal of Sport Medicine, 2021

Supplemental Digital Content is Available in the Text. Objective: To determine the effects of glu... more Supplemental Digital Content is Available in the Text. Objective: To determine the effects of glucocorticoids in enhancing athletic performance. Design: At least 2 independent reviewers conducted study selection and extracted demographic and outcome data. Relevant outcomes were stratified by administration time frame and the specific type of drug used. Study quality was assessed using the Cochrane Risk-of-Bias tool and the Cochrane Grading of Recommendations Assessment Development and Education scale. Where appropriate, meta-analyses were performed. Data sources: Embase, MEDLINE, and SPORTDiscus were searched from their beginning to April 2020. Participants: Participants of any sex and training status aged 18 to 65 years were included. Interventions and Main Outcome Measures: Any type of published randomized controlled trial (RCT) that examined any enhancement in sport as well as aerobic, anaerobic, or body compositional parameters for glucocorticoids compared with placebo. Results: There is low-to-moderate evidence suggesting that the administration of glucocorticoids may be more beneficial than placebo in enhancing athletic performance. short-term administration of glucocorticoids significantly improved time to exhaustion, maximal force, and total distance travelled. By contrast, acute administration of glucocorticoids predominantly yielded no changes to athletic performance, except for reductions in total work and maximal power output. Conclusions: Although there is evidence suggesting glucocorticoids have ergogenic effects, these improvements may differ depending on the specific type of drug, dose, and the administration time frame and are also limited by small sample sizes. Therefore, there is a need for large, high-quality RCTs as this may influence future doping policy and athlete care.

Rate Your Addiction Treatment Facility: Exploring the Quality Chasm Online

Journal of General Internal Medicine, 2020

Erratum to: Adult and Cancer Stem Cells: Perspectives on Autophagic Fate Determinations and Molecular Intervention

Current Cancer Research, 2016

Analysis of the Pharmacological and Molecular Heterogeneity of I2-Imidazoline-Binding Proteins using Monoamine Oxidase-Deficient Mouse Models

Molecular Pharmacology, 2000

The I 2 subgroup of imidazoline-binding sites was identified as monoamine oxidases (MAOs), but it... more The I 2 subgroup of imidazoline-binding sites was identified as monoamine oxidases (MAOs), but it is unclear whether there are I 2-binding sites located on proteins distinct from MAOs. To address this issue, we characterized I 2-binding proteins in liver and brain of wild-type and MAO A-and MAO B-deficient mice. I 2-binding sites were identified using [ 3 H]idazoxan and the photoaffinity adduct 2-[3-azido-4-[ 125 I]iodophenoxyl]methylimidazoline ([ 125 I]AZIPI). [ 3 H]Idazoxan labeled binding sites with ligand recognition properties typical of I 2 sites in both brain and liver of wild-type mice. High-affinity, specific [ 3 H]idazoxan binding were not altered in MAO A knockout (KO) mice. In contrast, [ 3 H]idazoxan binding was completely abolished in both liver and brain of MAO B KO mice. In wild-type mice, [ 125 I]AZIPI ABBREVIATIONS: I 2 BS, I 2-imidazoline-binding sites; MAO, monoamine oxidase; [ 125 I]AZIPI, 2-[3-azido-4-[ 125 I]iodophenoxyl]methyl imidazoline; KO, knockout.

Bidirectional promoter of human monoamine oxidase A (MAO A) controlled by transcription factor Sp1

The Journal of Neuroscience, 1994

We thank Joseuh Grimsbv for the ureliminarv Northern analvsis in detectine reverse transcripts an... more

Comparing medical, dental, and nursing students' preparedness to address lesbian, gay, bisexual, transgender, and queer health

PloS one, 2018

Lesbian, gay, bisexual, transgender, and queer (LGBTQ) populations face multiple health dispariti... more Lesbian, gay, bisexual, transgender, and queer (LGBTQ) populations face multiple health disparities including barriers to healthcare. Few studies have examined healthcare trainees' perceptions of their preparedness to care for LGBTQ populations and none have compared perceptions of training across medicine, dental medicine, and nursing. We aimed to understand variations across disciplines in LGBTQ health by assessing medical, dental, and nursing students' perceptions of preparedness across three domains: comfort levels, attitudes, and formal training. We developed a 12-item survey with an interprofessional panel of LGBTQ students from the schools of medicine, dental medicine, and nursing at a top-tier private university in the United States. Any student enrolled full time in any of the three schools were eligible to respond. We performed descriptive statistical analyses and examined patterns in responses using Kruskal-Wallis tests and an ordered logistic regression model. 1,...

Advancing precision medicine with personalized drug screening

Drug discovery today, Jan 17, 2018

Personalized drug screening (PDS) of approved drug libraries enables rapid development of specifi... more Personalized drug screening (PDS) of approved drug libraries enables rapid development of specific small-molecule therapies for individual patients. With a multidisciplinary team including clinicians, researchers, ethicists, informaticians and regulatory professionals, patient treatment can be optimized with greater efficacy and fewer adverse effects by using PDS as an approach to find remedies. In addition, PDS has the potential to rapidly identify therapeutics for a patient suffering from a disease without an existing therapy. From cancer to bacterial infections, we review specific maladies addressed with PDS campaigns. We predict that PDS combined with personal genomic analyses will contribute to the development of future precision medicine endeavors.

Early aseptic loosening of the Tritanium primary acetabular component with screw fixation

Arthroplasty today, 2018

Ultraporous acetabular components were developed to improve osseointegration and fit for increase... more Ultraporous acetabular components were developed to improve osseointegration and fit for increased longevity and better outcomes after total hip arthroplasty. There is a paucity of literature detailing this acetabular component's clinical performance, with even less detailing those with screw fixation. We identify 5 patients at our institution who underwent revision total hip arthroplasty for early aseptic acetabular cup loosening of an ultraporous acetabular component known as the Tritanium primary cup with secondary screw fixation. They all presented with groin and hip pain after index surgery and underwent follow-up radiographic examination consistent with component loosening requiring revision surgery. This case series reports on the risk of early acetabular cup loosening and its associated clinical presentation, workup, and surgical management in patients with the Tritanium primary cup augmented with screws.

ANATOMICAL AND FUNCTIONAL TESTING IN DIABETIC PATIENTS WITHOUT RETINOPATHY: Results of Optical Coherence Tomography Angiography and Visual Acuity Under Varying Contrast and Luminance Conditions

Retina (Philadelphia, Pa.), Jan 13, 2018

To assess early retinal microvascular and functional changes in diabetic patients without clinica... more To assess early retinal microvascular and functional changes in diabetic patients without clinical evidence of diabetic retinopathy with optical coherence tomography angiography and central visual analyzer. This was an observational case-control study of diabetic patients without diabetic retinopathy and nondiabetic controls. Patients underwent optical coherence tomography angiography imaging and visual acuity testing using the central visual analyzer. The foveal avascular zone area and the capillary density in the superficial and deep capillary plexuses were measured manually by a masked grader. Sixty eyes from 35 diabetic patients were included in the study group, and 45 eyes from 31 nondiabetic patients were included in the control group. The foveal avascular zone area was not significantly different between the diabetic group and controls (both P > 0.05). The mean capillary density in the deep capillary plexus was significantly lower in diabetic eyes compared with control eye...

Resolution, Depth of Field, and Physician Satisfaction During Digitally Assisted Vitreoretinal Surgery

Retina (Philadelphia, Pa.), Jan 27, 2018

To evaluate depth of field, lateral resolution, and image quality of a heads-up 3D visualization ... more To evaluate depth of field, lateral resolution, and image quality of a heads-up 3D visualization system for vitreoretinal surgery using physician survey and optical measurement outcomes. Depth of field and lateral resolution were compared between the standard ocular viewing system and the digital 3D system at ×5, ×13, and ×18 magnification by 6 retinal surgeons. Optical techniques were used as well as a survey of surgeon impression. Surgeon impression surveys were performed after 6 weeks of surgical use of the device. Physician questionnaire survey scores for depth of field at high magnification were better for the digital 3D system and equivalent for all other categories. Measured lateral resolution was 36.7 mm and 16.6 mm at ×5 magnification (P < 0.001), 14.3 mm and 6.4 mm at ×13 magnification (P < 0.001), and 9.8 mm and 4.2 mm (P < 0.001) at ×18 magnification for the digital 3D and oculars, respectively. Measured depth of field was 4.00 mm and 6.78 mm at ×5 magnification...

$Research paper thumbnail of {"__content__"=>"Interface Engineering of Monolayer MoS/GaN Hybrid Heterostructure: Modified Band Alignment for Photocatalytic Water Splitting Application by Nitridation Treatment.", "sub"=>{"__content__"=>"2"}}$

{"__content__"=>"Interface Engineering of Monolayer MoS/GaN Hybrid Heterostructure: Modified Band Alignment for Photocatalytic Water Splitting Application by Nitridation Treatment.", "sub"=>{"__content__"=>"2"}}

ACS applied materials & interfaces, Jan 14, 2018

Interface engineering is a key strategy to deal with the two-dimensional (2D)/three-dimensional (... more Interface engineering is a key strategy to deal with the two-dimensional (2D)/three-dimensional (3D) hybrid heterostructure, since the properties of this atomic-layer-thick 2D material can easily be impacted by the substrate environment. In this work, the structural, electronic, and optical properties of the 2D/3D heterostructure of monolayer MoS on wurtzite GaN surface without and with nitridation interfacial layer are systematically investigated by first-principles calculation and experimental analysis. The nitridation interfacial layer can be introduced into the 2D/3D heterostructure by remote N plasma treatment to GaN sample surface prior to stacking monolayer MoS on top. The calculation results reveal that the 2D/3D integrated heterostructure is energetically favorable with a negative formation energy. Both interfaces demonstrate indirect band gap, which is a benefit for longer lifetime of the photoexcited carriers. Meanwhile, the conduction band edge and valence band edge of t...

$Research paper thumbnail of {"__content__"=>"In Situ Resonant Raman Spectroscopy to Monitor the Surface Functionalization of MoS and WSe for High-k Integration: A First-Principles Study.", "sub"=>[{"__content__"=>"2"}, {"__content__"=>"2"}]}$

{"__content__"=>"In Situ Resonant Raman Spectroscopy to Monitor the Surface Functionalization of MoS and WSe for High-k Integration: A First-Principles Study.", "sub"=>[{"__content__"=>"2"}, {"__content__"=>"2"}]}

Langmuir : the ACS journal of surfaces and colloids, Feb 27, 2018

Surface functionalization of the dangling-bond-free MoS, WSe, and other TMDs (transition metal di... more Surface functionalization of the dangling-bond-free MoS, WSe, and other TMDs (transition metal dichalcogenides) is of large practical importance, for example, in providing nucleation sites for the subsequent high-k dielectric integration. Of the surface functionalization methods, the reversible O or N atom adsorption on top of the chalcogen atoms is most promising. However, hazards such as severe oxidation or nitridation persist when the adsorption coverage is high. An in situ characterization technique, which can be integrated with the surface functionalization and dielectric deposition chamber, becomes valuable to enable the real-time monitoring of surface adsorption conditions. Raman spectroscopy, as a nondestructive characterization method without vacuum requirement, is a strong candidate. By utilizing first-principles calculations, Raman spectra of single-layer MoS and WSe with various O/N adsorption coverages are studied. The calculations suggest that the low-coverage O/N adso...

Irrigation and Debridement for Early Periprosthetic Knee Infection: Is It Effective?

The Journal of arthroplasty, Jun 9, 2018

Irrigation and debridement (I&D) is performed for early management of periprosthetic joint infect... more Irrigation and debridement (I&D) is performed for early management of periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). Symptom reporting is a subjective measure and may miss direct management of PJI. Utilizing an objective time interval from index procedure to I&D may better inform treatment decisions. From 2009 to 2017, retrospective review was performed of 55 knee PJI cases at our institution. All patients underwent polyethylene liner exchange and I&D for PJI. Patients were stratified by time from index procedure to I&D (≤2 weeks, >2 weeks). Success was defined as eradication of infection and resolution of presenting symptoms. Failed cases required subsequent procedures due to infection. Average follow-up time after index TKA was 2.5 years. Among patients with I&D within 2 weeks of index TXA, 14 patients (82%) were successfully treated while 3 (18%) had infection recurrence. These outcomes were significantly improved compared to patients with I&D af...

Respiratory Synchronized Versus Intermittent Pneumatic Compression in Prevention of Venous Thromboembolism After Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

The Orthopedic clinics of North America, 2018

The objective of this study was to evaluate the efficacy of respiratory synchronized compression ... more The objective of this study was to evaluate the efficacy of respiratory synchronized compression devices (RSCDs) versus nonsynchronized intermittent pneumatic compression devices (NSIPCDs) in preventing venous thromboembolism (VTE) after total joint arthroplasty. A systematic literature review was conducted. Data regarding surgical procedure, deep vein thrombosis, pulmonary embolism, mortality, and adverse events were abstracted. Compared with control groups, the risk ratio of deep vein thrombosis development was 0.51 with NSIPCDs and 0.47 with RSCDs. This review demonstrates that RSCDs may be marginally more effective at preventing VTE events than NSIPCDs. Furthermore, the addition of mechanical prophylaxis to any chemoprophylactic regimen increases VTE prevention.