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The full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.

Despite several attempts to enhance the electrical and charge carrier transport characteristics of porous silicon (PSi), the requisite conditions for optimally synthesizing n-PSi with appealing optoelectronic properties are yet to be achieved. Therefore, this research explores the effect of the chemical ratio of precursor materials (HF:C2H6O:H2O2) on the surface morphology, crystalline structure, and optical and electric properties of PSi. The PSi was produced by photoelectrochemical etching followed by anodization of the n-type Si under light illumination. The properties of the as-prepared PSi were studied by means of microscopic and spectroscopic techniques. The HF:C2H6O:H2O2 chemical ratio was optimized at 2 : 1 : 1. A metal–semiconductor–metal (MSM) ultraviolet photodetector (Pt/n-PSi/Pt) was fabricated, which exhibited high performances under UV light (365 nm) illumination. The photodetector was shown to be highly stable and reliable with a rapid rise time of 0.56 s at a bias voltage of +5 V. The MSM photodetector displayed responsivity (Rp) of 9.17 A/m at 365 nm, which significantly exceeds the values reported for TiC/porous Si/Si in some contemporary research. The photodetector fabricated from n-PSi, synthesized at an optimum chemical ratio (2 : 1 : 1) exhibited the best photodetection performance, possibly due to the high porosity and defect-free state of the n-PSi thin films.

The International Conference of Harmonization (ICH) Q6A document provides guidance on setting specifications for new drug substances and drug products.

Lipid interaction with α-synuclein (αSyn) has been long implicated in the pathogenesis of Parkinson’s disease (PD). However, it has not been fully determined which lipids are involved in the initiation of αSyn aggregation in PD. Here exploiting genetic understanding associating the loss-of-function mutation in Synaptojanin 1 (SYNJ1), a phosphoinositide phosphatase, with familial PD and analysis of postmortem PD brains, we identified a novel lipid molecule involved in the toxic conversion of αSyn and its relation to PD. We first established a SYNJ1 knockout cell model and found SYNJ1 depletion increases the accumulation of pathological αSyn. Lipidomic analysis revealed SYNJ1 depletion elevates the level of its substrate phosphatidylinositol-3,4,5-trisphosphate (PIP3). We then employed Caenorhabditis elegans model to examine the effect of SYNJ1 defect on the neurotoxicity of αSyn. Mutations in SYNJ1 accelerated the accumulation of αSyn aggregation and induced locomotory defects in the nematodes. These results indicate that functional loss of SYNJ1 promotes the pathological aggregation of αSyn via the dysregulation of its substrate PIP3, leading to the aggravation of αSyn-mediated neurodegeneration. Treatment of cultured cell line and primary neurons with PIP3 itself or with PIP3 phosphatase inhibitor resulted in intracellular formation of αSyn inclusions. Indeed, in vitro protein–lipid overlay assay validated that phosphoinositides, especially PIP3, strongly interact with αSyn. Furthermore, the aggregation assay revealed that PIP3 not only accelerates the fibrillation of αSyn, but also induces the formation of fibrils sharing conformational and biochemical characteristics similar to the fibrils amplified from the brains of PD patients. Notably, the immunohistochemical and lipidomic analyses on postmortem brain of patients with sporadic PD showed increased PIP3 level and its colocalization with αSyn. Taken together, PIP3 dysregulation promotes the pathological aggregation of αSyn and increases the risk of developing PD, and PIP3 represents a potent target for intervention in PD.

Majorana bound states constitute one of the simplest examples of emergent non-Abelian excitations in condensed matter physics. A toy model proposed by Kitaev shows that such states can arise on the ends of a spinless $p$-wave superconducting chain. Practical proposals for its realization require coupling neighboring quantum dots in a chain via both electron tunneling and crossed Andreev reflection. While both processes have been observed in semiconducting nanowires and carbon nanotubes, crossed-Andreev interaction was neither easily tunable nor strong enough to induce coherent hybridization of dot states. Here we demonstrate the simultaneous presence of all necessary ingredients for an artificial Kitaev chain: two spin-polarized quantum dots in an InSb nanowire strongly coupled by both elastic co-tunneling and crossed Andreev reflection. We fine-tune this system to a sweet spot where a pair of Majorana bound states is predicted to appear. At this sweet spot, the transport characteristics satisfy the theoretical predictions for such a system, including pairwise correlation, zero charge, and stability against local perturbations of the Majorana state. While the simple system presented here can be scaled to simulate a full Kitaev chain with an emergent topological order, it can also be used imminently to explore relevant physics related to non-Abelian anyons., 35 pages, 11 figures

Diarrhea is a public health problem and an important cause of morbidity and mortality, enteroaggregative Escherichia coli (EAEC) have been recognized increasingly as agents of diarrhea in developing and in industrial countries. So the aim of this study is to study the prevalence of EAEC, its virulence factors and study it´s resistance to antibiotics. Results showed that E. coli represent 86 (32.9%) of the isolated bacteria. the high percentage 60% were EAEC, plasmid-encoded toxin (pet) was the marker most prevalent detected 14/30(28%) than EAST1(for EaggEC heat-stable enterotoxin 1)which detected in 9/30(18%) of EAEC and two virulence genes (pet+ and EAST1+) were found in7/30(14 %) of EAEC. 10% of isolates were contained capsule but only 3.3%isolates of E. coli have Type Ι pili while all the isolates possess Type ΙΙΙ pili. The results in the present study indicated that all E. coli were negative to Congo red dye agar test in contrast high percent of E. coli isolates were able to produce biofilm (86.7%) with different degree of thickness, while 20%isolates were urease positive after 24- 48 hrs, and 10% isolates were able to produce amylase. All isolates of E. coli were unable to produce Lecithinase, nuclease and hemolysin. While, 93.3% of E. coli isolates produced β-lactamase. The frequency of Sorbitol E. coli fermenter was 66.7%. In this study EAEC isolates were resistance (100%) to Penicillin and Ampicillin, High resistance(96.7%) was observed to each of Ceftriaxone, Cefotaxime and Trimethoprim. and Tetracycline (76.7%), resistance percentage of Both Amikacin and Rifampicin were (40%) and (33.3%) respectively. Higher sensitivity was reported to Gentamicin (63.3%), Ciprofloxacin(60%) then Nitrofurantoin (56.7%). The data from this study draw attention to the importance of notifying diarrheal disease. The high level of antimicrobial resistance observed in our study raises a broader discussion about the indiscriminate use or misuse of antibiotics and the risks of empirical antibiotic therapy in children of a very young age.

The current study Included the collection of samples (68) grit kidneys of patients undergoing surgery for lifting gravel in hospitals in the city of Tikrit and for the period from the month of April 2012 to the month of May 2013. The results of the study that people with the proportion of males (64.71%) while she was infected with the proportion of females (35.29 %) outweigh any male female ratio (1.83:1), diagnostic results showed depending on the biochemical tests and API-20system showed that E.coli and Ps.aeruginosa were the most frequent among other bacterial species and by isolating (30.76%) and (21.22%), respectively, while the bacteria P.mirabilis has given isolate percentage (15.38%) Followed by bacteria and Kl.pneumoniae Citrobacter.freundii by insolation (9.6%) and (5.67%) respectively, while giving the rest of the bacterial species (Staph.aureus,, Acinetobacter. freundii, E.faecalis Serratia .marscenes) isolation rate equal (3.84%), while isolating the bacteria Staph.epidermidis did not exceed (1.92%).The results of the investigation of the presence of genes,( mrpA, zapA, ureC) using polymerase chain reaction DNA (PCR) , Revealed that all isolates bacteria of P.mirabilis owning genes ( mrpA, zapA, ureC) encoding virulence factors (urease, protease, the ability to produce pili (mrp).

Aims: To assess the clinical, pathological and molecular characteristics (Sonic hedgehog and group 3/4 molecular subtypes expression) and treatment modalities for infantile medulloblastoma in correlation with outcomes. Materials & methods: A retrospective study of 86 medulloblastoma patients (≤3 years) was conducted. M0 patients

The study have been done to detecting HRSV infections among hospitalized children under 10 years old in Salahaldin Governorate, in addition to compare different diagnostic methods for detection of this virus. Nasopharyngeal Swabs (NPS) and whole blood samples were taken from 400 hospitalized children between end of August 2013, to the end of May 2014, each sample was analyzed for HRSV by Real time –PCR, IgM and IgG specific to HRSV determining from blood specimens in serum using enzyme linked immune sorbent assay (ELISA) technique. Nasopharyngeal Swab was more sensitive than the whole blood specimens for the detection of HRSV ,which is found in 1% by RT-PCR, in 81.9% by IgM –anti HRSV antibodies and in79.5% by IgG-HRSV antibodies. Autumn – winter periodwas considered as the most common time for HRSV infections with peak in September and February.

Children and adolescents are more vulnerable than other age groups to the psychosocial effects of the COVID-19 Pandemic. The modified DT (m-DT) was recently utilized for measuring the prevalence of psychological distress among adult COVID-19 patients. In the current study, we aimed to test the utilization of this m-DT in screening adolescent patients with COVID-19 for psychological distress.Egyptian adolescent subjects with suspected or confirmed cases of COVID-19 at a University Hospital were enrolled. Binary logistic regression tests were conducted to explore the association between the m-DT cutoff scores of 4 and the clinical variables.Forty-eight percent (87/182) of the study subjects experienced significant (m-DT score ≥ 4) COVID-19-related distress. There were substantial differences between those with and without considerable distress regarding the length of quarantine, underlying medical disorders, and the presence of chronic respiratory conditions. Length of quarantine time, chronic respiratory disease, worry, and fever were independent factors associated with significant distress in COVID-19 adolescent patients.Almost half of the enrolled Egyptian adolescents with COVID-19 experienced significant psychological distress. The m-DT was helpful, as the current study had identified length of quarantine time, presence of chronic respiratory disease, worry, and fever as independent factors associated with significant distress in COVID-19 adolescents. Further studies are needed. This article is protected by copyright. All rights reserved.

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children and young adults. Treatment is long and involves 2–3 years of a prolonged maintenance phase composed of oral chemotherapies. Adherence to these medications is critical to achieving good outcomes. However, adherence is difficult to determine, as there is currently no consensus on measures of adherence or criteria to determine nonadherence. Furthermore, there have been few studies in pediatric B-ALL describing factors associated with nonadherence. Thus, we performed a systematic review of literature on oral chemotherapy adherence during maintenance therapy in ALL following PRISMA guidelines. Published studies demonstrated various objective and subjective methods of assessing adherence without generalizable definitions of nonadherence. However, the results of these studies suggested that nonadherence to oral maintenance chemotherapy was associated with increased risk of relapse. Future studies of B-ALL therapy should utilize a uniform assessment of adherence and definitions of nonadherence to better determine the impact of nonadherence on B-ALL outcomes and identify predictors of nonadherence that could yield targets for adherence improving interventions.

The behavior of bispyribac-sodium and metribuzin herbicides was investigated into alluvial soil. Effect of pH, temperature, and particle size of soil on the sorption process was studied. Sorption isotherms by bulk soil and its sand, silt, clay and humic acid (HA) fractions were quantified using the batch equilibration technique. The results showed that sorption of herbicides tested was significantly affected by temperature and was a spontaneous interfacial process into soil. Freundlich equation accurately predicted the sorption behavior of two herbicides. Thermodynamic parameters summarized that the negative values of the standard free energy changes (ΔG˚) were obtained therefore, the adsorption of tested pesticides in soil was spontaneous and small negative values indicate the sorption is physical in nature involving weak forces of attraction. The negative ΔH˚ value, indicating metribuzin and bispyribac-sodium interactions are exothermic processes and products are energetically stable with a high binding of compound to soil sites. There was an increase in the entropy of tested pesticides-soil systems as shown by positive values of ΔS˚. The highest adsorption in soil was at pH 5 for bispyribac-sodium and at pH 7 for metribuzin. The sorption of metribuzin and bispyribac-sodium were significantly greater on HA fraction followed by clay fraction than the bulk soil. The KF and Kd values increase with decreasing particle size particularly in the case of adsorption of metribuzin.