Preparation of peroxidase: antiperoxidase (PAP) complexes for immunohistological labeling of monoclonal antibodies

The production of mouse peroxidase:antiperoxidase (PAP) complexes suitable for immunohistological use in conjunction with monoclonal antibodies is described. Three approaches were explored: 1) production of conventional polyclonal PAP complexes; 2) conversion of rabbit PAP to "pseudo-mouse PAP" by incubation with monoclonal mouse anti-rabbit immunoglobulin; 3) formation of PAP complexes from monoclonal mouse antiperoxidase. PAP complexes prepared by the latter technique gave the best immunohistological labeling reactions, being stable on storage and compatible with a wide range of human monoclonal antibodies. Gel filtration revealed that monoclonal PAP is of lower molecular weight than conventional PAP complexes (fulfilling theoretical predictions based on the monospecificity of monoclonal antibodies).     

Emerging 2D Layered Materials for Perovskite Solar Cells

Perovskite solar cells (PSCs) are now at the forefront of the state‐of‐the‐art photovoltaic technologies due to their high efficiency and low fabrication costs. To further realize the potential of this fascinating class of solar cells, nanostructured functional materials have been playing important roles. 2D layered materials have attracted a great deal of interest due to their fascinating properties and unique structure. Recently, the exploration of a wide range of novel 2D materials for use in PSCs has seen considerable progress, but still a lot remains to be done in this field. In this progress report, the advancements that have recently been made in the application of these emerging 2D materials, beyond graphene, for PSCs are presented. Both the advantages and challenges of these 2D materials for PSCs are highlighted. Finally, important directions for the future advancements toward efficient, low‐cost, and stable PSCs are outlined.     

Sex-specific differences in the prevalence of sarcopenia among pre-frail community-dwelling older adults in Saudi Arabia

ObjectivesTo assess sex differences in the prevalence of sarcopenia among pre-frail community-dwelling older adults in Saudi Arabia.MethodsThis was a cross-sectional study conducted at a tertiary-level hospital in Riyadh, Saudi Arabia, in 2019. The study participants were pre-frail community-dwelling older adults, according to the Edmonton Frail Scale. The SARC-F questionnaire was used to diagnose sarcopenia. The Katz Activities of Daily Living (ADL) was used to rank the adequacy of performance in six functions: bathing, dressing, toileting, transferring, continence, and feeding, while the Lawton Instrumental Activities of Daily Living scale was used to assess the more complex ADL necessary for living in the community.ResultsIn total, 283 community-dwelling older adults were recruited for this study, with a mean (±SD) age of 70.77 (±6.26) years; 72.7% of the total were female participants. The majority (85.5%) of the patients reported that they needed home care assistance. The mean ADL score of the participants was high, indicating high function and independence (KATZ-ADL: M 4.60 SD 1.75; Lawton Brody: 60%). The overall prevalence of sarcopenia among the studied participants was 65.7%, which was significantly higher among females (71.9%) than among males (59.1%), with a P-value of 0.007. Among the demographic characteristics of the participants, there was a significant difference in the need for home care assistance in female sarcopenic and non-sarcopenic participants (74.1% vs. 25.9%, p = 0.017), but without demonstrable difference in males. Additionally, there was a significant difference (P < 0.05) in the prevalence of sarcopenia between male and female participants according to ADL scores. The strongest predictor for sarcopenia prevalence in males was an ADL score <2 according to the Katz index, with an odds ratio of 6.5, while the need for home care was the only significant predictor of sarcopenia among female participants (OR 3.25, CI: 1.14–9.25, p = 0.02).ConclusionOverall, almost two-thirds of the studied pre-frail community-dwelling older adult population were sarcopenic. The prevalence of sarcopenia was significantly higher among females than males. The strongest predictor of sarcopenia was an ADL score <2 based on the Katz index in males and the need for home care assistance in females.     

Is social distancing a boon or bane for persons who stutter during COVID-19 pandemic?

The Covid-19 pandemic is an ongoing crisis and is colloquially known as the corona virus pandemic. As no specific treatment protocol are available for this viral infection, social distancing is considered as one of the remedies to prevent the infection. This study aimed to investigate the anxiety issues in persons who stutter (PWS). A total of 110 (55 PWS and 55 Neuro-typical Adults) were enrolled for the study. A questionnaire comprising of two parts on social anxiety and consequences of social distancing was administered on the participants. The results showed that PWS felt more socially anxious. PWS opined that they were comfortable during the corona virus lockdown period, as the situation demanded them to speak minimally to strangers. Neuro-typical adults, on the other hand, reported that they did not observe any change with respect to the social communication skills during lockdown.     

Dual Substrate Model for Novel Approach Towards a Kinetic Study of Acetylcholinesterase Inhibition by Diazinon

Limited reports as compared to other insecticides appear in the literature for acetylcholinester-ase (AChE) inhibition by diazinon. In the current study, new kinetic parameters of AChE inhibition by diazinon have been investigated. The assay was done with bovine retinal AChE using two different substrate (ASCh) concentrations in the absence and presence of diazinon (0.08-1.28 mM). The optical density was monitored up to 25min (reaction time) for the assay. New kinetic parameters (k¹_oms, k¹_sms, k¹_oms, k¹_sms, k¹_asms and k¹_asms) were calculated from these experimental data.     

Association of multiple drug resistance-1 gene polymorphism with multiple drug resistance in breast cancer patients from an ethnic Saudi Arabian population

Chemotherapy has been used widely to treat cancer, both as a systemic therapy and as a local treatment. Unfortunately, many types of cancer are still refractory to chemotherapy. The mechanisms of anticancer drug resistance have been extensively explored but have not been fully characterized. This study analyzed the occurrences of polymorphism (SNP) in the MDR1 gene in breast cancer patients and determined a possible association with chemotherapy. The study group included one hundred breast carcinoma patients who subsequently received chemotherapy (the regimen generally consisted of commonly used drugs such as cyclophosphamide, adriamycin, 5-fluorouracil, docetaxel and their combinations). Blood samples from 100 healthy individuals are used, as controls were also genotyped for the MDR1 gene. This investigation revealed a significant correlation with response to various regimens of chemotherapy showing a low response to therapy with the CT/TT genotype at (exon 12) 1236 codon (p < 0.001). These findings demonstrate, for the first time, that the polymorphisms in (exon 12) 1236 codon of the MDR1 gene greatly influence the drug response in patients from the Arab population of Saudi Arabia.     

On the genetic diversity of spiny mice (genus Acomys) and gerbils (genus Gerbillus) in the Arabian Peninsula

Using non-destructive sampling we provide further genetic characterisations for spiny mice (Acomys dimidiatus/cahirinus) and gerbils (Gerbillus sp.) in three regions in Saudi Arabia. All individuals were sequenced for a fragment of the cytochrome b gene, and compared against available conspecifics and closely related taxa. We confirm the existence of a second Acomys dimidiatus/cahirinus lineage specific to the Arabian Peninsula as seen previously. The Arabian Gerbillus nanus is shown to group with Middle Eastern rather than African conspecifics. A second cryptic Gerbillus lineage was also sampled across multiple locations, which may be an uncharacterised G. dasyurus.     

Ti3C2Tx (MXene)‐Silicon Heterojunction for Efficient Photovoltaic Cells

A novel type of solar cell has been developed based on charge separation at the heterojunction formed by a transparent conducting MXene electrode and an n‐type silicon (n‐Si) wafer. A thin layer of the native silicon dioxide plays an important role in suppressing the recombination of charge carriers. A two‐step chemical treatment can increase the device efficiency by about 40%. Promisingly, an average power conversion efficiency of over 10% under simulated full sunlight is achieved for this novel class of solar cell with the application of an antireflection layer. The efficiencies of these novel solar cells based on a MXene‐Si heterojunction achieved in this work point to great promise in emerging photovoltaic technology. In addition to their high efficiency, the excellent reproducibility of such devices establishes a solid base for possible future commercialization.     

Impact of off-road vehicles on soil and vegetation in a desert rangeland in Saudi Arabia

Off-road vehicle driving is considered as main contributor to land degradation in arid regions. This study examined the impact of off-road vehicles (ORV) on soil and vegetation in a natural recreational desert meadow of Raudhat Khuraim, Saudi Arabia. Vegetation canopy cover and plant height away from road tracks were assessed. Also, species density and canopy cover, bare ground cover and soil attributes were assessed in four microhabitats; tracks, inter-tracks, verges, and away from vehicle tracks (undisturbed natural areas). Results show that the cover of forbs and grasses was negatively associated with distance from road verges. It was observed that the height of woody species responded negatively to distance away from tracks. Cover of native species decreased under verge, inter-track and track microhabitats giving more opportunity for weeds to flourish. Bare ground was highest (60.7%) in tracks. ORV impact on soil bulk density was clear with an increase of 38% under tracks compared to soils of undisturbed natural vegetation and a similar decrease in porosity was observed. On the other hand, soil electrical conductivity was significantly higher (5.45 mS cm^?1) under disturbance compared to 1.32 mS cm^?1 in undisturbed natural vegetation. Organic matter and nitrogen were not affected significantly by ORV disturbance. The results emphasize that managing off-road vehicle driving is essential for conserving native vegetation.