Papers by Mohamed A . Hassan
International journal of molecular sciences, Jan 8, 2015
Lectins are non-immunoglobulin proteins that bind diverse sugar structures with a high degree of ... more Lectins are non-immunoglobulin proteins that bind diverse sugar structures with a high degree of selectivity. Lectins play crucial role in various biological processes such as cellular signaling, scavenging of glycoproteins from the circulatory system, cell-cell interactions in the immune system, differentiation and protein targeting to cellular compartments, as well as in host defence mechanisms, inflammation, and cancer. Among all the sources of lectins, plants have been most extensively studied. However, more recently fungal lectins have attracted considerable attention due to their antitumor, antiproliferative and immunomodulatory activities. Given that only 10% of mushroom species are known and have been taxonomically classified, mushrooms represent an enormous unexplored source of potentially useful and novel lectins. In this review we provide an up-to-date summary on the biochemical, molecular and structural properties of mushroom lectins, as well as their versatile applicati...
Proteins, Mar 7, 2017
A lectin with strong cytotoxic effect on human colon cancer HT29 and monkey kidney VERO cells was... more A lectin with strong cytotoxic effect on human colon cancer HT29 and monkey kidney VERO cells was recently identified from the Australian indigenous mushroom Psathyrella asperospora and named PAL. We herein present its biochemical and structural analysis using a multidisciplinary approach. Glycan arrays revealed binding preference towards Nacetylglucosamine (GlcNAc) and, to a lesser extent, towards sialic acid (Neu5Ac). Submicromolar and millimolar affinity was measured by surface plasmon resonance for GlcNAc and NeuAc, respectively. The structure of PAL was resolved by X-ray crystallography, elucidating both the protein's amino acid sequence as well as the molecular basis rationalizing its binding specificity.
ChemInform, Aug 20, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Journal of environmental chemical engineering, Jun 1, 2015
Interactions between polyacrylic acid (PAA) and polyethyleneimine (BPEI) were investigated in the... more Interactions between polyacrylic acid (PAA) and polyethyleneimine (BPEI) were investigated in the absence and in the presence of metal cations (M) over a large pH-range. These interactions led to the formation of complexes with sizes in the range from colloids to particles. The sizes of the complexes, structures of the resulting media and free metal concentrations were strongly dependent on the way reactants were put into contact. Best conditions for metal separation were obtained when the polycation was used to neutralise the anionic PAA-M complex since it resulted in fast gravity separation of metals and low residual concentrations. A single-step ultrafiltration (UF) treatment was also studied and compared to a two-step treatment made of gravity separation and UF of supernatants in terms of quality and volumetric rates for treated wastewater.
Analytica Chimica Acta, 1985
ABSTRACT
Journal of Thermal Analysis and Calorimetry, Jan 9, 2007
Journal of Thermal Analysis, 1994
Confirmations of the successful synthesis of a particular zeolite demand investigation of the cry... more Confirmations of the successful synthesis of a particular zeolite demand investigation of the crystals by XRD, SEM, MAS-NMR and chemical analysis. In this work, we have used the DTA exothermic lattice breakdown of theA-zeolite, which gives typical peaks at around 900–1200°C for characterization. The effects ofpH, concentration, time of crystallization and temperature were studied and it was quickly and easily possible to distinguishA-zeolite formation from others originating from the synthesis matrix under different conditions by using DTA/TG analyses. The parameters were optimized for the synthesis of the zeolite and DTA measurements yielded enough information to identify theA-zeolite; this was confirmed by XRD and SEM.ZusammenfassungDer Nachweis einer erfolgreichen Synthese spezieller Zeolithe erfordert die Untersuchung des Kristalles mittels XRD, SEM, MAS-NMR und mittels chemischer Analyse. Vorliegend wurde der im DTA exotherme Gitterzerfall von Zeolith-A verwendet, welcher zur Charakterisierung typische Peaks zwischen 900 und 1200°C liefert. Es wurde der Einfluß vonpH-Konzentration, Kristallisationsdauer und Temperatur untersucht und eine Identifizierung der Zeolith-A Bildung war mittels DTA/TG-Analyse unter verschiedenen Bedingungen, schnell und leicht möglich. Die Parameter wurden für die Zeolith-Synthese optimiert und DTA-Messungen boten genügend Informationen zur Identifizierung von Zeolith-A, was mittels XDR und SEM noch bestätigt wurde.
Applied Surface Science, 1995
X-ray photoelectron spectroscopy (XPS) has been applied to the characterization of barium-impregn... more X-ray photoelectron spectroscopy (XPS) has been applied to the characterization of barium-impregnated MFI high-silica zeolites which are used for the conversion of methanol to light alkenes. X-ray photoelectron spectroscopy provided info~ation about the degree of the dispersion of the various barium loadings on the silicalite structure, and this info~ation helped in elucidating the observed relationship between the activity/selectivity of the catalysts and the barium loading. The XPS results also helped in predicting that the performance of the catalyst would be optimized at 4 wt% Ba loading which was found to agree with the catalytic conversion of methanol to light alkenes.
África, Dec 7, 2021
La vie politique djiboutienne de 1992 à 2021 : quelques réflexions sur le changement et les réfor... more La vie politique djiboutienne de 1992 à 2021 : quelques réflexions sur le changement et les réformes politiques. Résumé: Depuis 1992 le modèle de changement politique retenu par les autorités politiques djiboutiennes n'a pas aboutit à une alternance au pouvoir. L'introduction de la compétition électorale ni l'apparition d'une Commission Electorale Nationale Indépendante en 2002 n'ont aboutit à l'apparition d'un régime politique où l'opposition dispose d'un statut. Les réformes constitutionnelles ultérieures et surtout la suppression de la norme limitant les mandats présidentiels en 2010 ont renforcé plus le pouvoir du président qu'une réelle évolution du système vers un régime où il y a la libre expression et le respect de l'opposition politique, qui a eu ses premiers députés lors des dernières élections législatives en février dernier. Cependant la situation socioéconomique a beaucoup changé avec l'accroissement des investissements étrangers, provenant des pays d'Asie et du monde arabe par la transformation du Port de Djibouti en hub régional.
The fabrication of polypropylene (PP)/ recycled acrylonitrile butadiene rubber (NBRr)/ empty frui... more The fabrication of polypropylene (PP)/ recycled acrylonitrile butadiene rubber (NBRr)/ empty fruit bunch (EFB) composites were investigated. The effects of polypropylene maleic anhydride (PPMAH) as a compatibilizer on the mechanical and morphological properties of PP/NBRr/EFB composites were studied. Composites were prepared through melt mixing using heated two roll mill at 180 °C for 9 minutes and rotor speed of 15 rpm. NBRr loading were varied from 0 to 60 phr and PPMAH was fixed for 5 phr. The composites were moulded into a 1 mm thin sheet using hot press machine and then cut into dumbbell shape. The mechanical and morphological properties of composites were examined using universal tensile machine (UTM) and scanning electron microscope (SEM), respectively. Tensile strength and Young’s modulus of PP/NBRr/EFB composites decreased with increasing NBRr loading, whilst increasing the elongation at break. However, PPMAH compatibilized composites have resulted 27% to 40% and 25% to 42% higher tensile strength and Young’s modulus, respectively, higher compared to uncompatibilized composites. This was due to the better adhesion between PP/NBRr matrices and EFB filler with the presence of maleic anhydride moieties. From the morphological study, the micrograph of PPMAH compatibilized composites has proved the well bonded and good attachments of EFB filler with PP/NBRr matrices which results better tensile strength to the PP/NBRr/EFB composites.The fabrication of polypropylene (PP)/ recycled acrylonitrile butadiene rubber (NBRr)/ empty fruit bunch (EFB) composites were investigated. The effects of polypropylene maleic anhydride (PPMAH) as a compatibilizer on the mechanical and morphological properties of PP/NBRr/EFB composites were studied. Composites were prepared through melt mixing using heated two roll mill at 180 °C for 9 minutes and rotor speed of 15 rpm. NBRr loading were varied from 0 to 60 phr and PPMAH was fixed for 5 phr. The composites were moulded into a 1 mm thin sheet using hot press machine and then cut into dumbbell shape. The mechanical and morphological properties of composites were examined using universal tensile machine (UTM) and scanning electron microscope (SEM), respectively. Tensile strength and Young’s modulus of PP/NBRr/EFB composites decreased with increasing NBRr loading, whilst increasing the elongation at break. However, PPMAH compatibilized composites have resulted 27% to 40% and 25% to 42% higher tensile strengt...
Zeolites, 1996
MFI-type zeolites were synthesized by the rapid crystallization method in 2 h. The synthesis para... more MFI-type zeolites were synthesized by the rapid crystallization method in 2 h. The synthesis parameters were studied briefly using a statistical method, and the pH of the initial hydrogel was found to be the most critical parameter under the synthesis conditions used and the crystallization time constrain. The physicochemical properties of the zeolite products were studied and found to have some advantages over conventionally synthesized zeolites. The thermal stability was found to decrease with increasing SVAI ratio contrary to what was widely accepted. It was speculated that high concentrations of defect sites exaggerated by the rapid crystallization time may be responsible for the trend of thermal stability.
Journal of Chromatographic Science, 1990
Applied Catalysis A: General, 1997
The reaction of isobutene and methanol to produce methyl tert-butyl ether (MTBE) has been studied... more The reaction of isobutene and methanol to produce methyl tert-butyl ether (MTBE) has been studied over MFI-type zeolites (ZSM-5) with varying Si/Al ratios. All the zeolites were synthesized by the rapid crystallization method. The number of Brönsted acid sites on the zeolite ...
Applied Catalysis A: General, 1997
Catalytic conversion of methanol to light alkenes was investigated using a high silica zeolite of... more Catalytic conversion of methanol to light alkenes was investigated using a high silica zeolite of the pentasil type MFI structure. The reaction was carried out in a fixed bed reaction setup at 400°C, WHSV =4 h-i, pressure of 1 atm, and MeOH]N 2 (wt) ratio of 2.78. The silicalite zeolite (UC-S-115) was modified by impregnation with metal nitrates of Ag, Ca, Cd, Cu, Ga, In, La and Sr to study their effects on the activity and selectivity of the catalyst to lower alkenes. Incorporation of La and Ag led to an improvement in light alkene selectivity of the silicalite by 18% and 14% respectively. This was attributed to enhanced shape selectivity of the silicalite resulting from reduction of the apparent pore size of zeolite channels. The active life-on-stream was slightly decreased due to coke deposition. A non-rigorous least square fit of the catalyst life exhibited an exponential decay as a function of coke deposition rate above 0.17 wt% h-1. Below 0.17 wt% h-l however, the active life-on-stream becomes insensitive to the rate of coking and is probably determined largely by catalyst intrinsic properties.
The Analyst, 1995
Raney nickel, Houston Atlas and gas chromatographic-flame photometric detection (GC-F&amp... more Raney nickel, Houston Atlas and gas chromatographic-flame photometric detection (GC-F'PD) methods were applied to the determination of trace amounts of sulfur in naphthas. The parameters investigated included the linearity, detection limits and the repeatability of ...
In May 2000, an unusual fixed airways obstruction in eight workers of a microwave popcorn plant i... more In May 2000, an unusual fixed airways obstruction in eight workers of a microwave popcorn plant in Missouri brought up national attention. However, the cause of this lung disease, resembling bronchiolitis obliterans, was due to exposure to the predominant vapor of diacetyl that gives the smell and flavor of butter to popcorn. Following that, many more cases of lung disease were reported in 2002-2006 which resulted in passing the Popcorn Workers Lung Disease Prevention Act in 2007. Diacetyl can be made in through fermentation, and a copper catalyst. It gives the butter flavor and taste to some foods such as popcorn, dairy products, coffee, and alcoholic beverages. Diacetyl can be a product from decomposition of methyl ethyl ketone. The companies primarily synthesize diacetyl to use it as a food additive. A large number of workers are exposed to diacetyl, as a result of its production and usage in the food industries. NIOSH performed an experiment in the 1980's and found that thousands of workers were potentially exposed to diacetyl in the United States. Exposure to diacetyl may occur through inhalation of butter flavoring vapors, ingestion of foods and drinking water containing diacetyl, and dermal contact with consumer products containing this compound. These exposures may pose some significant health risks to the related workers particularly for those working directly with the substance. Due to its relatively low vapor pressure, diacetyl is an airborne chemical in butter-flavoring for popcorn. Studies showed that diacetyl inhalation causes some lung problems in the workers who mix oil and butter flavoring at the plant depending on length of exposure. These issues can be mentioned as severe injury of the epithelium airway, shortness of breath, and cough as a result of manufacturing buttered popcorn. The prominent upper respiratory tract issues including sensory and nasal tissue irritation and inflammation were considered. Testing of rats for acute and subchronic studies indicate the upper respiratory tract to be a significant target for symptoms due to cytotoxic effects of diacetyl vapor. Workers chronic exposure to diacetyl may result to a nonreversible lung disease called bronchiolitis obliterations. Those who work in facilities with open containers of artificial butter flavoring are more susceptible to diacetyl exposure. Smokers and children if exposed to the vapor would be affected more when considering their forced expiratory volume.
Plant Archives, 2021
In one stage of mankind’s struggle to keep pace with ever increasing demand of food due to accele... more In one stage of mankind’s struggle to keep pace with ever increasing demand of food due to accelerating world population, chemical fertilizers contributed enormously to produce sufficient food products. However, a stagnation in the crop productivity along with decreasing soil fertility status and environmental pollution due to continuous, excessive, and imbalanced use of chemical fertilizers. In this scenario, plant growth promoting rhizobacteria (PGPR) become a natural choice as an alternative to the fertilizer to alleviate excessive consumption of fertilizers because PGPR not only promote nutrient availability to plants as biofertilizers but also performin several ways to stimulate plant growth and hence their productivity. In this review, an attempt has been made to highlight the main activities of PGPR in soil and plants, and to analyse their mode of actions from chemistry point of view.
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Papers by Mohamed A . Hassan
Despite the absence of recognized statehood, non-state actors have emerged as key players in
addressing human rights challenges and fostering a rights-based society. Through advocacy, service
provision, and capacity-building initiatives, they have contributed to raising awareness about human
rights, challenging discriminatory practices, and supporting vulnerable groups. The importance of
collaboration among non-state actors and with international organizations to maximize their impact.
Capacity-building initiatives are crucial for enhancing their skills and knowledge in human rights
advocacy, monitoring, and documentation. Engaging constructively with state institutions can help
influence policy-making processes and integrate human rights considerations into the legal framework.
Non-state actors play a vital role in raising public awareness about human rights through educational
programs, public campaigns, and community outreach. International support in the form of financial
and technical assistance is necessary to sustain their efforts in the long term. The contributions of Nonstate actors in Hargeisa, Somaliland in the protection and promotion of human rights are crucial for
ensuring the well-being and dignity of the population, non-state actors can continue to make a
significant impact in advancing human rights and fostering positive social change in the region.
investigates the factors influencing teacher turnover in public secondary schools in Hargeisa, Somaliland, with
a focus on insights provided by the Regional Education Office. The research employs a mixed-methods approach,
combining quantitative surveys and qualitative interviews with teachers and education officials to identify key
determinants of teacher retention and attrition.
The findings reveal that low salaries and inadequate benefits significantly undermine teacher morale, job
satisfaction, and overall motivation, contributing to high turnover rates. Classroom overcrowding and limited
resources further exacerbate these challenges, making it difficult for teachers to manage classrooms effectively
and implement engaging teaching methods. Additionally, the study highlights that while some teachers perceive
the Regional Education Office as supportive of innovation and creativity, there is a divided opinion on the fairness
and transparency of teacher evaluation and feedback policies.
Budgetary constraints, restrictive government policies, and systemic issues present substantial challenges for the
Regional Education Office in addressing these problems. The study concludes that improving teacher salaries
and benefits, reducing workload and administrative burdens, and ensuring fair and transparent evaluation
processes are crucial strategies for enhancing teacher retention. These measures can create a more supportive
and motivating work environment, ultimately benefiting the educational outcomes for students in public
secondary schools in Hargeisa.
This research provides valuable insights for policymakers, educational administrators, and stakeholders in the
education sector, offering practical recommendations to mitigate teacher turnover and improve the overall
quality of education in Somaliland.
outcomes of construction projects in Hargeisa, drawing from a study completed within the city.
The construction sector in Hargeisa is easily affected by changes in scope caused by a range of
unpredictable factors such as weather, changing stakeholder needs, and varying resource
availability. Successfully managing these changes in scope is essential to guarantee the project's
achievement, usually evaluated based on timing, expenses, excellence, and meeting stakeholder
expectations.
population was the employee at Ministry of investment and industrial development. Primary data was
used in the research work, the study adopted sampling technique while data was analyzed using the
SPSS and including the use of percentages, means and standard deviation and inferential analysis on
variables. The geographical location of the study was limited to the Hargeisa context, especially the
Ministry of investment and industrial development. Most respondents agreed that the lack of job
rotation can lead the organization to poor performance. Also, an overwhelming majority of
respondents do believe that job rotation has had a strong relationship on the organization performance
and the majority of respondents approved of the deep understanding of job rotation ensure the
achievement of organizational goals. The result from the findings of this study reveals that job rotation
and employee performance has a strong relationship and significant effect on organization’s
performance in Ministry of investment and industrial development Hargeisa Somaliland. Based on the
research findings the researcher recommended the following points the organizations must give job
rotation to improve the employee performance. Particularly methods of job rotation.an effective
training technique for fields that require a specific set of skills for operating complex machinery,
Simulations training which affects employee performance, on job training which increase level quality,
Coaching/mentoring training has an impact on employee performance hence there is monitoring
training. And Films and Video has quickly gained popularity as an effective technique, so they impact
on satisfaction.
Office in 2004, youth (15-24) become nearly half (47%) of the world’s unemployed in the population, 88 million
out of 186 million, even though youth are become only 25% of the world’s working age group. In regionally
Unemployment of youth is particularly concerning given east Africa, Somalia’s70% of the populations are
below the age of 30 so that they have not an opportunities to get job according to Their low of education and
skills, coupled with inadequate livelihood opportunities, is seen as a driver of radicalization, migration and
membership of extremist and other armed groups (Awil Abdinor Yusuf, 2019).
According to Somaliland Ministry of Labor and Social Affairs (2014), there are no official statistical data
regarding the current youth population in Somaliland, but the latest assessment of unemployment rate indicates
that 65% of Somaliland people are unemployed. According to this data, 30 % of the unemployed are females
while 20% are young males, but the remaining rate 15% are adults. The assessment noted that Hargeisa which
is the capital city of Somaliland has been constrained by high levels of unemployed youth (Muse Abdilahi
Muhumed (2014). The researcher applied descriptive research design. This is because the researcher was
gathering quantitative and qualitative data that describes unemployment youth According to Sekeran (2003),
finally On the basis of the knowledge of the study, would recommend”; 1. To improve skill development because
skill development is essential for increasing productivity and sustainability as well improving working
conditions along with the employability worker. In order to secure that the first job as well as negative in the
labor market, young women and men needs the technical skills to perform specific task as well as core work
skills wealth learning to learn, communication problem solving and teamwork development of core skills,
awareness of workers, rights and understanding of an entrepreneurships are the building blocks for lifelong
learning and capability to adapt to change. 2. To pick up self-knowledge and emotional intelligence: in general
the younger generation need to know themselves because when a worker understands him or herself, he or she
can make adjustments where needed and perform at his or her best. Young people who know how to approach
and solve problems, but are also well again able to work with others.