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排序方式: 共有195条查询结果,搜索用时 31 毫秒
41.
Abdullah Alhendal Randa Abd Almoaeen Mohamed Rashad Ali Husain Fouzi Mouffouk Zahoor Ahmad 《RSC advances》2022,12(28):18077
This work describes the preparation of an analytical microextraction sorbent using a simple and versatile sol–gel hybrid composite, i.e., aramid oligomers wrapping multi-walled carbon nanotubes (CNTs) covalently bonded to a porous silica network. To overcome the inherent shortcomings of the CNTs'' solubility and dispersion in both organic phases and in the sol–gel solution, the outer surface of the CNTs was initially functionalized with carboxylic acid groups and then reacted with both aramid oligomers and 3-aminopropyl triethoxysilane (APTES). The obtained sorbent was characterized by FT-IR, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Using sol–gel chemistry, the functionalized CNTs were coated onto SPME fibers and used in conjunction with GC-MS for the analysis of polycyclic aromatic hydrocarbons (PAHs) in water and soil samples. Excellent repeatability (run-to-run RSD% ∼ 8) and reproducibility (fiber-to-fiber RSD% ∼ 6) were achieved in addition to low LODs (0.10–0.30 ng mL−1) and noticeable recovery%. The present method of sorbent preparation led to enhanced thermal and chemical stabilities, a long sorbent lifetime and good affinity towards PAHs. Moreover, the present sorbent enhanced the extraction capability by more than 30% compared to that of commercially available PDMS counterparts.This work describes the preparation of an analytical microextraction sorbent using a simple and versatile sol–gel hybrid composite, i.e., aramid oligomers wrapping multi-walled carbon nanotubes (CNTs) covalently bonded to a porous silica network. 相似文献
42.
PCR assay targeting virulence genes of Helicobacter pylori isolated from drinking water and clinical samples in Lahore metropolitan, Pakistan 下载免费PDF全文
Helicobacter pylorus is considered for chronic gastritis, gastric ulcers and adenocarcinoma and its high infection rate is observed in overcrowded and lower socioeconomic groups in developing countries. This study was designed to identify the role of drinking water in the transmission and prevalence of H. pylori (HP). Selective HP medium was developed for enrichment and presumptive identification of H. pylori by urease, catalase and species specific 16S rRNA tests. The virulence genes (vacA s and m regions and cagA) of H. pylori in 90 out of 225 H. pylori positive drinking water samples were present (40%). Ten out of 18 biopsies (55.55%) and 15 out of 50 vomiting fluids of gastric disease patients (30%) were also positive for virulence genes. Anti-H. pylori antibodies were also detected in 31 out of 50 patients sera. The presence of virulence genes was also directly confirmed by hybridization studies using non-radioactive DNA probes of 16S rRNA, vacA and cagA genes. The presence of H. pylori in water is due to poor sanitary conditions, improper waste disposal and lack of public health education. PCR-based analysis and colony hybridization can be used for detection of H. pylori in clinical and environmental samples. 相似文献
43.
Syed Ayaz Kazmi Abdul Rauf Mohammed Merae Alshahrani Ahmed Abdullah Al Awadh Zahoor Iqbal Raya Soltane ElSayed Tag-Eldin Altaf Ahmad Zulqarnain Ansari Zia-ur-Rehman 《Viruses》2022,14(9)
Background: Very few studies have been reported on hepatitis B in the State of Azad Jammu and Kashmir, Pakistan, and none of them are specific to the prevalence and causes of hepatitis B spread among educational institutes. This study aimed to estimate the prevalence of hepatitis B infection and its associated risk factors among the University of AJ and K population. Methods: An observational, cross-sectional, and analytical study was conducted with 7015 students and employees. Hepatitis B was detected by rapid immunochromatographic tests (ICTs), enzyme-linked immunosorbent assay (ELISA), and real-time quantitative PCR. A questionnaire and interview method was used to assess the disease knowledge and associated risk factors with hepatitis B through Chi-square, Fisher’s exact test, and paired t-test. Results: Of the participants, 150 (2.13%) were found positive for the hepatitis B surface antigen (57.3% male and 42.7% female). Only 0.3% participants were found fully vaccinated against the hepatitis B virus. Among ethnic groups, the Syed tribe was found more prevalent for hepatitis B infection (40.6%), while use of contaminated mourning blades (95% CI: p = 0.0001) was found as an overlooked risk factor. Hepatitis preventive awareness sessions were found to be very significant (p = 0.0001). Conclusions: The study showed that an overlooked risk factor is playing a key role in the spread of HBV in a tribe living worldwide, which must be addressed globally to eradicate hepatitis B. In Pakistan, a country-wide annual HBV vaccination program should be launched to control hepatitis B. 相似文献
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Zeenat Salahuddin Muhammad Yasir Zahoor Saeeda Kalsoom 《The Australian journal of forensic sciences》2018,50(4):355-360
Bloodstains are extremely important forensic evidence for DNA profiling. The current study has been planned to quantify DNA recovery from a list of fabrics tested after washing. On each fabric, spots of blood was dotted, and the dried-bloodstained fabrics were hand washed with tap water, soaked in tap water with detergent and then hand washed, for 5 and 10 min. DNA was extracted through Chelex100 from these fabrics and quantified through Real Time PCR using the Quantifiler Human DNA Quantification kit. Results showed that DNA can be recovered from fabrics after they have been washed. The amount of recovered DNA is comparable among these fabrics and did not show significant variations with washing methods. Blends of fabrics showed the highest recovery while non-absorbent fabrics showed least DNA recovery. Knowledge of the different DNA quantities recovered from washed fabrics will be useful in solving criminal cases. The ability to recover DNA from washed fabrics could prove important in forensic casework. 相似文献
47.
Mamoon Ur Rashid Muhammad Alamzeb Saqib Ali Zahoor Ullah Zafar Ali Shah Ishrat Naz Muhammad Rafiullah Khan 《Phytotherapy research : PTR》2019,33(10):2661-2684
Several reviews have been published on Artemisia's derived natural products, but it is the first attempt to review the chemistry and pharmacology of more than 80 alkaloids and allied nitrogen compounds obtained from various Artemisia species (covering the literature up to June 2018). The pharmacological potential and unique skeleton types of certain Artemisia's alkaloids provoke the importance of analyzing Artemisia species for bioactive alkaloids and allied nitrogen compounds. Among the various types of bioactive Artemisia's alkaloids, the main classes were the derivatives of rupestine (pyridine–sesquiterpene), lycoctonine (diterpene), pyrrolizidine, purines, polyamine, peptides, indole, piperidine, pyrrolidine, alkamides, and flavoalkaloids. The rupestine derivatives are Artemisia's characteristic alkaloids, whereas the rest are common alkaloids found in the family Asteraceae and chemotaxonomically links the genus Artemisia with the tribes Anthemideae. The most important biological activities of Artemisia's alkaloids are including hepatoprotective, local anesthetic, β‐galactosidase, and antiparasitic activities; treatment of angina pectoris, opening blocked arteries, as a sleep‐inducing agents and inhibition of HIV viral protease, CYP450, melanin biosynthesis, human carbonic anhydrase, [3H]‐AEA metabolism, kinases, and DNA polymerase β1. Some of the important nitrogen metabolites of Artemisia include pellitorine, zeatin, tryptophan, rupestine, and aconitine analogs, which need to be optimized and commercialized further. 相似文献
48.
Zahoor Syed Frank Dudbridge Lindsey Kent 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2007,(3):375-378
Attention deficit hyperactivity disorder (ADHD) is a common, highly heritable, neurodevelopmental disorder with onset in early childhood. Genes involved in neuronal development and growth are, thus, important etiological candidates and neurotrophic factors have been hypothesized to play a role in the pathogenesis of ADHD. Glial derived neurotrophic factor (GDNF), nerve growth factor (NGF (beta subunit)), and neurotrophic factor 3 (NT3) are members of the neurotrophin family and are involved in the survival, differentiation, and maintenance of neuronal cells. We have examined 10 coding and intronic single nucleotide polymorphisms (SNPs) across GDNF, NGF, and NT3 in a family-based association sample of 120 DSM-IV ADHD probands and their biological parents, as well as a case-control analysis with 120 sex-matched controls. Borderline significant overtransmission of the C allele of a non-synonymous C/T SNP (rs6330) in NGF which codes an alanine/valine change was found in the family-based sample (Chi-square = 3.69, odds ratio (OR) = 1.65, P = 0.05). Although this SNP is located in the 5' pro-NGF sequence and not the mature NGF protein, it may affect intracellular processing and secretion of NGF. 相似文献
49.
What is behind the ear drum? The microbiology of otitis media and the nasopharyngeal flora in children in the era of pneumococcal vaccination 下载免费PDF全文
50.
Ali Hassan Bakhtiar Ahmad Zahoor Ahmed Khalid W. Al-Quliti 《Neurosciences (Riyadh, Saudi Arabia)》2015,20(1):61-64
Ruptured cerebral aneurysm is the most common cause of spontaneous subarachnoid hemorrhage (SAH). Rarely cerebral venous sinus thrombosis (CVST) may present initially as acute SAH, and clinically mimics aneurysmal bleed. We report 2 cases of CVST who presented with severe headache associated with neck pain and focal seizures. Non-contrast brain CT showed SAH, involving the sulci of the convexity of hemisphere (cSAH) without involving the basal cisterns. Both patients received treatment with anticoagulants and improved. Awareness of this unusual presentation of CVST is important for early diagnosis and treatment. The purpose of this paper is to emphasize the inclusion of vascular neuroimaging like MRI with venography or CT venography in the diagnostic workup of SAH, especially in a patient with strong clinical suspicion of CVST or in a patient where neuroimaging showed cSAH.Spontaneous subarachnoid hemorrhage (SAH) suggests the presence of a vascular lesion, most commonly ruptured cerebral aneurysm. It is rare for SAH to be associated with cerebral venous sinus thrombosis (CVST), and its location is usually different from the arterial aneurysms.1,2 The exact pathogenesis of SAH associated with CVST remains unknown; however, it is believed that it is probably induced by the rupture of dilated thin-walled cortical veins.1 Diagnosis of CVST associated with SAH usually depends on a high index of clinical suspicion combined with radiologic confirmation, so that appropriate treatment can be timely initiated. To date, 74 cases of CVST with radiological evidence of SAH, usually seen at the cerebral convexities, have been reported in the literature.3,4We are reporting 2 cases of superior sagittal sinus (SSS) thrombosis that presented initially with SAH. Our objective in presenting these cases is to highlight the fact that CVST may present early as SAH, and vascular neuroimaging should be considered in selected cases, especially those cases, in which cerebral aneurysm is not detected and there is still a clinical suspicious of CVST. We also have addressed the non-aneurysmal convexity SAH (cSAH) which is being increasingly recognized with characteristic radiological pattern of venous SAH, as opposed to aneurysmal SAH. The use of systemic anticoagulation as an initial therapy of CVST, even in the presence of SAH is also briefly discussed. 相似文献