Background: Central nervous system lesions are rare causes of respiratory failure. Simple observa... more Background: Central nervous system lesions are rare causes of respiratory failure. Simple observation of the breathing pattern can help localize the lesion, but the examiner needs to be aware of potential pitfalls such as metabolic or pulmonary alterations. Methods: We describe 3 cases in which central neurogenic respiratory failure occurred simultaneously with other alterations or in an unusual presentation. Results: All patients were diagnosed with central neurogenic respiratory failure and treated for it with good recovery. Conclusion: Central neurogenic respiratory failure is a challenging diagnosis and needs to be reminded in difficult-to-wean patients carrying inconclusive evidences of metabolic or pulmonary alterations.
Background: Central nervous system lesions are rare causes of respiratory failure. Simple observa... more Background: Central nervous system lesions are rare causes of respiratory failure. Simple observation of the breathing pattern can help localize the lesion, but the examiner needs to be aware of potential pitfalls such as metabolic or pulmonary alterations. Methods: We describe 3 cases in which central neurogenic respiratory failure occurred simultaneously with other alterations or in an unusual presentation. Results: All patients were diagnosed with central neurogenic respiratory failure and treated for it with good recovery. Conclusion: Central neurogenic respiratory failure is a challenging diagnosis and needs to be reminded in difficult-to-wean patients carrying inconclusive evidences of metabolic or pulmonary alterations.
Many publications have pointed out Carbon Dioxide (CO 2 ) as an environmental friendly refrigeran... more Many publications have pointed out Carbon Dioxide (CO 2 ) as an environmental friendly refrigerant fluid aiming to reduce the level of CO 2 emissions from refrigerating appliances. The possibility of replacing HFCs by employing CO 2 compressors has been leading the refrigeration industry to a continuos research on all the related fields. Concerning CO 2 application, significant progress in terms of both energy performance and reliability have been made by the optimization of the reciprocating compressor to meet CO 2 design demands. From a broader perspective, this paper intends to assess the acoustical performance of an energy efficient, reliable CO 2 reciprocating compressor through the identification of the sources and transmission paths, associating them to the overall sound level of both the compressor itself and a representative refrigerating appliance. Advanced methods are applied including numerical analysis, operational deflection shape (ODS), and acoustical holography to investigate the potential of a brand new reciprocating compressor platform designed for CO 2 application . The methodology employed is presented and has its scope on identifying, quantifying and judging the sources of the noise, transmission paths, and respective influences in the final radiator acoustical performance. Preliminary results point to a very positive perspective for the acoustical performance of the CO 2 compressor investigated, showing similar sound level when comparing to current baseline.
1. ABSTRACT HFC refrigerant has been identified as a contributing factor with regard to global wa... more 1. ABSTRACT HFC refrigerant has been identified as a contributing factor with regard to global warming. This fact has put pressure on most of the refrigeration industry to replace the HFC refrigerant fluids currently employed in vapor compression systems. In this search for an environmental friendly technology, Carbon Dioxide (CO 2) has emerged as a leading candidate to be a replacement for HFCs. Today there is a strong focus on CO 2 potential for beverage cooling application although it is still in the preliminarily stages. Moreover, in the design of compressors to run with high pressure refrigerants like CO 2 safety aspects must be a mandatory concern. When dealing with high pressure levels, compressor components have their original design adapted to withstand such a high pressures, particularly acoustical mufflers, external shell, and compression mechanism. Regarding the external shell, the design approach goes beyond acoustical and aesthetics features as mostly observed in current refrigerating compressors. In order to safely enclose the compression mechanism the application of a proper design methodology is mandatory to safeguard the structural integrity of both the compressor external shell and the whole refrigerating system. Looking for acceptable, cost-effective safety factors, a simultaneous design approach including advanced structural mechanics techniques, experimentation, safety standards revision, and Computer Aided Engineering (CAE) tools application is mandatory. The aim of this work is to present how Embraco has been approaching the structural design of its CO 2 compressor to ensure safety and reliability. Also, a comparison between a CO 2 compressor under development and a standard HFC compressor has been performed in both calorimeter and application tests. Preliminary data have showed that a CO 2 can perform competitively to the HFC systems in the field.
In the design of compressors running with high pressure refrigerants, safety aspects must be a ma... more In the design of compressors running with high pressure refrigerants, safety aspects must be a mandatory concern. Moreover, when dealing with high pressure levels, compressor components have their original design adapted to withstand such a high pressures, particularly ...
This work is focused on the evaluation of the performance of a single stage CO 2 reciprocating co... more This work is focused on the evaluation of the performance of a single stage CO 2 reciprocating compressor working on a beverage cooler application. A glass door merchandiser (GDM) was tested to develop a procedure to determine the best combination of capillary tube and refrigerant charge. Fin and tube heat exchangers were used both for the evaporator and the gas cooler. The criteria to choose the combination was the total energy consumption of the system. The theoretical optimum discharge pressure was determined point by point during the "ON" period of the cycle and was compared to the experimental discharge pressure. The results showed that the closer profile to the optimum profile was the best in terms of energy consumption. The system was also tested with R134a and the results were compared showing 26% of energy savings in favor of the CO 2 system.
Sydenham’s chorea is associated with dysfunction of fronto-striatal circuits induced by cross-rea... more Sydenham’s chorea is associated with dysfunction of fronto-striatal circuits induced by cross-reactive antibodies to group A β-hemolytic streptococcus. High susceptibility of extrapyramidal effects of neuroleptics in patients with Sydenham’s chorea suggests underlying nigro-striatal dysfunction.To study the presence of parkinsonism in patients with a history of Sydenham’s Chorea.We used the UFMG Sydenham’s Chorea Rating Scale (USCRS) and the Unified Parkinson’s Disease Rating Scale (UPDRS) part III, respectively, to determine the presence of chorea and parkinsonian symptoms and signs in 25 adults with a history of previous Sydenham’s Chorea currently without chorea or use of anti-choreic drugs.Bradykinesia was found in 64% of subjects. There was a statistically significant correlation between bradykinesia and hemichorea (−0.412; p = 0.036) and bradykinesia and generalized chorea (0.412; p = 0.036). There was no correlation between bradykinesia and use of anti-choreic drugs.Bradykinesia is common in patients with Sydenham’s Chorea in remission. This finding suggests an immune-mediated dysfunction of the nigro-striatal system.
Phacomatosis pigmentokeratotica is characterized by the coexistence of nevus sebaceus, papular ne... more Phacomatosis pigmentokeratotica is characterized by the coexistence of nevus sebaceus, papular nevus spilus and associated neurologic abnormalities. We report a case of phacomatosis pigmentokeratotica in a 28-year-old male who presented with palmar-plantar dysesthesia and ipsilateral brain hemiatrophy. As a characteristic neuroimaging finding of the disorder, we found multiple hypointense lesions involving the ipsilateral hemisphere. (J Dermatol Case Rep. 2014; 8(2): 58-59)
Sydenham&... more Sydenham's chorea is associated with dysfunction of fronto-striatal circuits induced by cross-reactive antibodies to group A β-hemolytic streptococcus. High susceptibility of extrapyramidal effects of neuroleptics in patients with Sydenham's chorea suggests underlying nigro-striatal dysfunction. To study the presence of parkinsonism in patients with a history of Sydenham's Chorea. We used the UFMG Sydenham's Chorea Rating Scale (USCRS) and the Unified…
Background: Central nervous system lesions are rare causes of respiratory failure. Simple observa... more Background: Central nervous system lesions are rare causes of respiratory failure. Simple observation of the breathing pattern can help localize the lesion, but the examiner needs to be aware of potential pitfalls such as metabolic or pulmonary alterations. Methods: We describe 3 cases in which central neurogenic respiratory failure occurred simultaneously with other alterations or in an unusual presentation. Results: All patients were diagnosed with central neurogenic respiratory failure and treated for it with good recovery. Conclusion: Central neurogenic respiratory failure is a challenging diagnosis and needs to be reminded in difficult-to-wean patients carrying inconclusive evidences of metabolic or pulmonary alterations.
Background: Central nervous system lesions are rare causes of respiratory failure. Simple observa... more Background: Central nervous system lesions are rare causes of respiratory failure. Simple observation of the breathing pattern can help localize the lesion, but the examiner needs to be aware of potential pitfalls such as metabolic or pulmonary alterations. Methods: We describe 3 cases in which central neurogenic respiratory failure occurred simultaneously with other alterations or in an unusual presentation. Results: All patients were diagnosed with central neurogenic respiratory failure and treated for it with good recovery. Conclusion: Central neurogenic respiratory failure is a challenging diagnosis and needs to be reminded in difficult-to-wean patients carrying inconclusive evidences of metabolic or pulmonary alterations.
Many publications have pointed out Carbon Dioxide (CO 2 ) as an environmental friendly refrigeran... more Many publications have pointed out Carbon Dioxide (CO 2 ) as an environmental friendly refrigerant fluid aiming to reduce the level of CO 2 emissions from refrigerating appliances. The possibility of replacing HFCs by employing CO 2 compressors has been leading the refrigeration industry to a continuos research on all the related fields. Concerning CO 2 application, significant progress in terms of both energy performance and reliability have been made by the optimization of the reciprocating compressor to meet CO 2 design demands. From a broader perspective, this paper intends to assess the acoustical performance of an energy efficient, reliable CO 2 reciprocating compressor through the identification of the sources and transmission paths, associating them to the overall sound level of both the compressor itself and a representative refrigerating appliance. Advanced methods are applied including numerical analysis, operational deflection shape (ODS), and acoustical holography to investigate the potential of a brand new reciprocating compressor platform designed for CO 2 application . The methodology employed is presented and has its scope on identifying, quantifying and judging the sources of the noise, transmission paths, and respective influences in the final radiator acoustical performance. Preliminary results point to a very positive perspective for the acoustical performance of the CO 2 compressor investigated, showing similar sound level when comparing to current baseline.
1. ABSTRACT HFC refrigerant has been identified as a contributing factor with regard to global wa... more 1. ABSTRACT HFC refrigerant has been identified as a contributing factor with regard to global warming. This fact has put pressure on most of the refrigeration industry to replace the HFC refrigerant fluids currently employed in vapor compression systems. In this search for an environmental friendly technology, Carbon Dioxide (CO 2) has emerged as a leading candidate to be a replacement for HFCs. Today there is a strong focus on CO 2 potential for beverage cooling application although it is still in the preliminarily stages. Moreover, in the design of compressors to run with high pressure refrigerants like CO 2 safety aspects must be a mandatory concern. When dealing with high pressure levels, compressor components have their original design adapted to withstand such a high pressures, particularly acoustical mufflers, external shell, and compression mechanism. Regarding the external shell, the design approach goes beyond acoustical and aesthetics features as mostly observed in current refrigerating compressors. In order to safely enclose the compression mechanism the application of a proper design methodology is mandatory to safeguard the structural integrity of both the compressor external shell and the whole refrigerating system. Looking for acceptable, cost-effective safety factors, a simultaneous design approach including advanced structural mechanics techniques, experimentation, safety standards revision, and Computer Aided Engineering (CAE) tools application is mandatory. The aim of this work is to present how Embraco has been approaching the structural design of its CO 2 compressor to ensure safety and reliability. Also, a comparison between a CO 2 compressor under development and a standard HFC compressor has been performed in both calorimeter and application tests. Preliminary data have showed that a CO 2 can perform competitively to the HFC systems in the field.
In the design of compressors running with high pressure refrigerants, safety aspects must be a ma... more In the design of compressors running with high pressure refrigerants, safety aspects must be a mandatory concern. Moreover, when dealing with high pressure levels, compressor components have their original design adapted to withstand such a high pressures, particularly ...
This work is focused on the evaluation of the performance of a single stage CO 2 reciprocating co... more This work is focused on the evaluation of the performance of a single stage CO 2 reciprocating compressor working on a beverage cooler application. A glass door merchandiser (GDM) was tested to develop a procedure to determine the best combination of capillary tube and refrigerant charge. Fin and tube heat exchangers were used both for the evaporator and the gas cooler. The criteria to choose the combination was the total energy consumption of the system. The theoretical optimum discharge pressure was determined point by point during the "ON" period of the cycle and was compared to the experimental discharge pressure. The results showed that the closer profile to the optimum profile was the best in terms of energy consumption. The system was also tested with R134a and the results were compared showing 26% of energy savings in favor of the CO 2 system.
Sydenham’s chorea is associated with dysfunction of fronto-striatal circuits induced by cross-rea... more Sydenham’s chorea is associated with dysfunction of fronto-striatal circuits induced by cross-reactive antibodies to group A β-hemolytic streptococcus. High susceptibility of extrapyramidal effects of neuroleptics in patients with Sydenham’s chorea suggests underlying nigro-striatal dysfunction.To study the presence of parkinsonism in patients with a history of Sydenham’s Chorea.We used the UFMG Sydenham’s Chorea Rating Scale (USCRS) and the Unified Parkinson’s Disease Rating Scale (UPDRS) part III, respectively, to determine the presence of chorea and parkinsonian symptoms and signs in 25 adults with a history of previous Sydenham’s Chorea currently without chorea or use of anti-choreic drugs.Bradykinesia was found in 64% of subjects. There was a statistically significant correlation between bradykinesia and hemichorea (−0.412; p = 0.036) and bradykinesia and generalized chorea (0.412; p = 0.036). There was no correlation between bradykinesia and use of anti-choreic drugs.Bradykinesia is common in patients with Sydenham’s Chorea in remission. This finding suggests an immune-mediated dysfunction of the nigro-striatal system.
Phacomatosis pigmentokeratotica is characterized by the coexistence of nevus sebaceus, papular ne... more Phacomatosis pigmentokeratotica is characterized by the coexistence of nevus sebaceus, papular nevus spilus and associated neurologic abnormalities. We report a case of phacomatosis pigmentokeratotica in a 28-year-old male who presented with palmar-plantar dysesthesia and ipsilateral brain hemiatrophy. As a characteristic neuroimaging finding of the disorder, we found multiple hypointense lesions involving the ipsilateral hemisphere. (J Dermatol Case Rep. 2014; 8(2): 58-59)
Sydenham&... more Sydenham's chorea is associated with dysfunction of fronto-striatal circuits induced by cross-reactive antibodies to group A β-hemolytic streptococcus. High susceptibility of extrapyramidal effects of neuroleptics in patients with Sydenham's chorea suggests underlying nigro-striatal dysfunction. To study the presence of parkinsonism in patients with a history of Sydenham's Chorea. We used the UFMG Sydenham's Chorea Rating Scale (USCRS) and the Unified…
Uploads
Papers by Ricardo Maciel