Green synthesis of silver nanoparticles employing hamdard joshanda extract: putative antimicrobial potential against gram positive and gram negative bacteria

The bio-mediated synthesis of nanoparticles offers a sustainable and eco-friendly approach. In the present study, silver nanoparticles (AgNPs) were synthesized using Joshanda extract, a commercially available herbal formulation derived from a traditional medicinal plant, as a reducing and stabilizing agent. The as-synthesized AgNPs were characterized using UV-Vis spectroscopy, dynamic light scattering (DLS), X-ray Diffraction (XRD) study, and Fourier-transform infrared (FTIR) analysis. UV-Vis spectroscopy exhibited a prominent absorption peak at 430 nm, confirming the formation of AgNPs. DLS analysis revealed the size distribution of the nanoparticles, ranging from 80 to 100 nm, and zeta potential measurements indicated a surface charge of - 14.4 mV. The XRD analysis provide evidence for the presence of a face-centered cubic structure within the silver nanoparticles. FTIR analysis further elucidated the interaction of bioactive compounds from the Joshanda extract with the AgNPs' surface. Strong peaks at 765-829 cm-1 indicated C-Cl stretching vibrations of alkyl halides, while the stretching of alkenes C=C was observed at 1641 cm-1. Moreover, the presence of alcohols and phenol (OH) groups was identified at 3448 cm-1, suggesting their involvement in nanoparticle stabilization. The antimicrobial potential of the synthesized AgNPs was evaluated against both gram-negative Pseudomonas aeruginosa and gram-positive Streptococcus mutans using zone of inhibition assays. The AgNPs exhibited remarkable inhibitory effects against both types of bacteria. Additionally, AgNPs-treated groups demonstrated a significant increase in reactive oxygen species (ROS) levels, indicating potential of as-synthesized AgNPs in disruption of the target microbial membranes. Furthermore, the as-synthesized AgNPs exhibited notable anti-biofilm properties by effectively hindering the development of mature biofilms. This study highlights the efficient green synthesis of AgNPs using Joshanda extract and also provides insights into their physico-chemical properties of as-synthesized nanoparticles. The demonstrated antimicrobial activity against both gram-negative and gram-positive bacteria, along with biofilm inhibition potential, underscores the promising applications of the as-synthesized AgNPs in the field of biomedical and environmental sciences. The study bridges traditional knowledge with contemporary nanotechnology, offering a novel avenue for the development of eco-friendly antimicrobial agents.

Exploring chemical space, scaffold diversity, and activity landscape of spleen tyrosine kinase active inhibitors

This study aims to comprehensively characterize 576 inhibitors targeting Spleen Tyrosine Kinase (SYK), a non-receptor tyrosine kinase primarily found in haematopoietic cells, with significant relevance to B-cell receptor function. The objective is to gain insights into the structural requirements essential for potent activity, with implications for various therapeutic applications. Through chemoinformatic analyses, we focus on exploring the chemical space, scaffold diversity, and structure-activity relationships (SAR). By leveraging ECFP4 and MACCS fingerprints, we elucidate the relationship between chemical compounds and visualize the network using RDKit and NetworkX platforms. Additionally, compound clustering and visualization of the associated chemical space aid in understanding overall diversity. The outcomes include identifying consensus diversity patterns to assess global chemical space diversity. Furthermore, incorporating pairwise activity differences enhances the activity landscape visualization, revealing heterogeneous SAR patterns. The dataset analysed in this work has three activity cliff generators, CHEMBL3415598, CHEMBL4780257, and CHEMBL3265037, compounds with high affinity to SYK are very similar to compounds analogues with reasonable potency differences. Overall, this study provides a critical analysis of SYK inhibitors, uncovering potential scaffolds and chemical moieties crucial for their activity, thereby advancing the understanding of their therapeutic potential.

Unveiling the Latest Advancements in Vanadium Carbide MXene based Supercapacitors and their Future Trends

Vanadium-carbide-based MXenes have bewitched the scientific community due to their distinctive characteristics, which make them potential candidates for several technological applications, such as supercapacitors (SCs), batteries, gas separation, biological sensors, and desalination. This article provides an overview of recent developments in the synthesis and applications of vanadium-carbide MXene in SCs. Vanadium carbide is one of the most difficult MXenes to synthesize, and various synthesis techniques, including electrochemical exfoliation and chemical etching, have been utilized to fabricate this material. Additionally, the review article also emphasizes the potential use of vanadium carbide MXene as SCs. Finally, the paper concludes with the challenges faced in the synthesis process and the prospects of vanadium carbide MXene-based material fabrication. Overall, this review article provides in-depth and detailed information on recent research on vanadium carbide MXene and its possible uses.

An In Silico Investigation of Pharmacological Modulators and Inflammasomes in Glioblastoma Multiforme

For the past decades, inflammatory signals have been considered a possible key for pharmacological interventions. There are several compounds and/or molecules that have been known as most promising medication against inflammation and its mediated chronic disorders. Inflammasomes could be recognized as a trigger by detrimental stimuli as pathogenic attack and endogenous signals mediated injury inside the cells. In addition, there has been an inflammatory key mechanism involved in cancers including glioblastoma multiforme (GBM). GBM has been considered the foremost aggressive primary brain tumors in adult stage. There is a scattered beam of light on both cellular and molecular links in inflammation and GBM. However, the immune response of GBM has been characterized extensively by macrophages and lymphocytes related to tumors, and some recent investigations have pinpointed the focus of inflammasomes on the progression of GBM. Nevertheless, risk factors linked with GBM are still debatable. In our study, the most considerable compounds and their bonded and/or targeted proteins have depicted the most promising highlights under in silico condition. Our in silico investigations have revealed a powerful pharmacological agents/compound against inflammasome-mediated GBM.

Recombinant expression and preliminary characterization of Peptidyl-prolyl cis/trans-isomerase Rrd1 from Saccharomyces cerevisiae

Sacchromycescerevisiae Peptidyl-prolylcis/trans-isomerase Rrd1 has been linked to DNA repair, bud morphogenesis, advancement of the G1 phase, DNA replication stress, microtubule dynamics and is also necessary for the quick decrease in Sgs1p levels in response to rapamycin. In present study, Rrd1 gene was amplified by standard PCR and subsequently cloned downstream to bacteriophage T7 inducible promoter and lac operator of expression vector pET21d(+). Additionally, immobilized metal affinity chromatography (IMAC) was used to purify the protein upto its homogeneity, and its homogeneous purity was further confirmed through western blotting. Size exclusion chromatography implies that Rrd1 is existing as monomer in its natural state. Foldwise Rrd1 protein belongs to PTPA-like protein superfamily. Rrd1 showed characteristic negative minima at 222 and 208 nm represent protein typically acquired α helix in the far-UV CD spectra. Fluorescence spectra showed properly folded tertiary structures of Rrd1 at physiological conditions. Rrd1protein can be identified from different species using a fingerprint created by PIPSA analysis. The protein's abundance could aid in its crystallization, biophysical characterization and identification of other-interacting partners of Rrd1 protein.

Association of peptidyl prolyl cis/trans isomerase Rrd1 with C terminal domain of RNA polymerase II

The largest subunit of RNAPII extends as the conserved unstructured heptapeptide consensus repeats Y₁S₂P₃T₄S₅P₆S₇ and their posttranslational modification, especially the phosphorylation state at Ser2, Ser5 and Ser7 of CTD recruits different transcription factors involved in transcription. In the current study, fluorescence anisotropy, pull down assay and molecular dynamics simulation studies employed to conclude that peptidyl-prolyl cis/trans-isomerase Rrd1 has strong affinity for unphosphorylated CTD rather than phosphorylated CTD for mRNA transcription. Rrd1 preferentially interacts with unphosphorylated GST-CTD in comparison to hyperphosphorylated GST-CTD in vitro. Fluorescence anisotropy revealed that recombinant Rrd1 prefers to bind unphosphorylated CTD peptide in comparison to phosphorylated CTD peptide. In computational studies, the RMSD of Rrd1-unphosphorylated CTD complex was greater than the RMSD of Rrd1-pCTD complex. During 50 ns MD simulation run Rrd1-pCTD complex get dissociated twice viz. 20 ns to 30 ns and 40 ns to 50 ns, while Rrd1-unpCTD complex remain stable throughout the process. Additionally, the Rrd1-unphosphorylated CTD complexes acquire comparatively higher number of H-bonds, water bridges and hydrophobic interactions occupancy than Rrd1-pCTD complex, concludes that the Rrd1 interacts more strongly with the unphosphorylated CTD than the pCTD.

Incidence and molecular characterization of extended-spectrum beta-lactamase (ESBL)-producing Salmonella enterica and Escherichia coli of avifauna origin in Pakistan

Members of Enterobacteriaceae are known to produce extended-spectrum beta-lactamases (ESBL) which hydrolyze the beta-lactam group of antibiotics. The existence of ESBL-producing Salmonella enterica (S. enterica) and Escherichia coli (E. coli) harbored by urban avifauna was investigated in this study. Dropping samples (n= 180) were collected from six different bird species in the district Jhang, Punjab province, Pakistan. Isolation and identification of ESBL isolates were made by using cefotaxime- (4 mg/L) supplemented MacConkey agar and double disc synergy test (DDST). Polymerase chain reaction (PCR) was performed for the detection of four different ESBL genes including blaCTX-M, blaTEM, blaSHV and blaOXA. A total of 42.69% isolates were confirmed as ESBL via DDST including 30.64% S. enterica and 49.54% E. coli. The incidence of ESBL S. enterica and ESBL E. coli was found highest in egret (Ardea alba) and pigeon (Columba livia) as 64.28% and 78.95%, respectively. The blaCTX-M gene was detected in 57.89% and 64.81% of isolates of S. enterica and E. coli, respectively. Among other genes in S. enterica and E. coli, blaTEM (21.05%, 20.4%); blaSHV (15.78%, 9.26%), and blaOXA (5.26%, 5.56%) were detected, respectively. All of the tested isolates were found resistant to at least one of the thirteen antimicrobial agents except meropenem. To the best of our knowledge, this is the first study reporting the incidence and genetic diversity of ESBL bacteria associated with urban avifauna in Pakistan. The urban avifauna can serve as a potential subject of bio-surveillance to monitor the emergence of antimicrobial-resistant bacteria.

β Pore-forming Protein-based Evolutionary Divergence of Gnathostomata from Agnatha

INTRODUCTION

The first vertebrates were jawless fish, or Agnatha, whose evolution diverged into jawed fish, or Gnathostomes, around 550 million years ago.

METHODS

In this study, we investigated β PFT proteins' evolutionary divergence of lamprey immune protein from Agnatha, reportedly possessing anti-cancer activity, into Dln1 protein from Gnathostomes. Both proteins showed structural and functional divergence, and shared evolutionary origin. Primary, secondary and tertiary sequences were compared to discover functional domains and conserved motifs in order to study the evolution of these two proteins. The structural and functional information relevant to evolutionary divergence was revealed using hydrophobic cluster analysis.

RESULTS

The findings demonstrate that two membrane proteins with only a small degree of sequence identity can have remarkably similar hydropathy profiles, pointing towards conserved and similar global structures. When facing the lipid bilayer or lining the pore lumen, the two proteins' aerolysin domains' corresponding residues displayed a similar and largely conserved pattern. Aerolysin-like proteins from different species can be identified using a fingerprint created by PIPSA analysis of the pore-forming protein.

CONCLUSION

We were able to fully understand the mechanism of action during pore formation through structural studies of these proteins.

A Recent Update on Pathophysiology and Therapeutic Interventions of Alzheimer's Disease

AIM

Alzheimer's disease (AD) has been identified as a progressive brain disorder associated with memory dysfunction and the accumulation of β-amyloid plaques and neurofibrillary tangles of τ protein. Mitochondria is crucial in maintaining cell survival, cell death, calcium regulation, and ATP synthesis. Mitochondrial dysfunction and linked calcium overload have been involved in the pathogenesis of AD. CRM2 (Collapsin response mediator protein-2) is involved in endosomal lysosomal trafficking as well as autophagy, and their reduced level is also a primary culprit in the progression of AD. In addition, Cholinergic neurotransmission and neuroinflammation are two other mechanisms implicated in AD onset and might be protective targets to attenuate disease progression. The microbiota-gut-brain axis (MGBA) is another crucial target for AD treatment. Crosstalk between gut microbiota and brain mutually benefitted each other, dysbiosis in gut microbiota affects the brain functions and leads to AD progression with increased AD-causing biomarkers. Despite the complexity of AD, treatment is only limited to symptomatic management. Therefore, there is an urgent demand for novel therapeutics that target associated pathways responsible for AD pathology. This review explores the role of different mechanisms involved in AD and possible therapeutic targets to protect against disease progression.

BACKGROUND

Amidst various age-related diseases, AD is the most deleterious neurodegenerative disorder that affects more than 24 million people globally. Every year, approximately 7.7 million new cases of dementia have been reported. However, to date, no novel disease-modifying therapies are available to treat AD.

OBJECTIVE

The aim of writing this review is to highlight the role of key biomarker proteins and possible therapeutic interventions that could play a crucial role in mitigating the ongoing prognosis of Alzheimer's disease.

MATERIALS AND METHODS

The available information about the disease was collected through multiple search engines, including PubMed, Science Direct, Clinical Trials, and Google Scholar.

RESULTS

Accumulated pieces of evidence reveal that extracellular aggregation of β-amyloid plaques and intracellular tangles of τ protein are peculiar features of perpetuated Alzheimer's disease (AD). Further, the significant role of mitochondria, calcium, and cholinergic pathways in the pathogenesis of AD makes the respiratory cell organelle a crucial therapeutic target in this neurodegenerative disease. All currently available drugs either delay the clinical damage to cells or temporarily attenuate some symptoms of Alzheimer's disease.

CONCLUSION

The pathological features of AD are extracellular deposition of β-amyloid, acetylcholinesterase deregulation, and intracellular tangles of τ protein. The multifactorial heterogeneity of disease demands more research work in this field to find new therapeutic biological targets.

Molecular detection and therapeutic study of Trypanosoma brucei evansi from naturally infected horses in Punjab, Pakistan

Trypanosomiasis is one of the severe pathogenic infections, caused by several Trypanosoma species, affecting both animals and humans, causing substantial economic losses and severe illness. The objective of this study was to determine the molecular diagnosis and the risk factors associated with trypanosomiasis in District Jhang, Punjab, Pakistan. For this purpose, blood samples were randomly collected from 200 horses. A predesigned questionnaire was used to collect data on risk factors before the sample collection. The microscopy examination through Giemsa staining, formol gel test and PCR techniques were used to find the prevalence. The prevalence was recorded as 22.5% with microscopy examination, 21% through formol gel test and 15.5% with PCR based results. Analysis of risk factors associated with Trypanosoma brucei evansi occurrence was carried out using Chi-square test. It showed the prevalence of Trypanosoma brucei evansi was significantly (p⟨0.05) associated with sex, age, rearing purpose and body condition whereas non-significantly (p⟩0.05) with insects control practices. This study supports the idea that PCR is a sensitive, robust and more reliable technique to diagnose trypanosomiasis. It was concluded that Trypanosoma brucei evansi is widely prevalent in Jhang (Pakistan), highlighting a dire need to develop control strategies and education programmes to control this disease in developing countries.

Framework for the analysis of renewable energy grid policies in the context of COVID-19

COVID-19 is a severe global pandemic that has caught the whole world unprepared. In the absence of a clear timeline for this pandemic to end, it is need of the hour to investigate the effect of this pandemic on both previous and anticipated investments. Global economic unrest has hindered the ramping deployment of Renewable energy projects.The most quick actions that may be taken to mitigate the effects and to up-rise the investment portfolio policies are a very critical tool in hands of government for a very immediate effect have also been made without keeping the context of COVID-19 into account.New variants of diff rent nature are being discovered and every now and then new lock downs are happening. In this context different policies have to be evaluated under the pandemic scenario. A case study of a large scale renewable energy project for a higher education institute in Pakistan is being used to measure the difference during COVID and pre COVID times. This paper provides a framework to investigate the impact of COVID on renewable energy system projects under current net-metering, net-billing and self-consumption policies. A recent investment in a photovoltaic system is assessed based on previously projected financial benefits versus the pandemic effected ones. This research concludes that investing in photovoltaic systems are still a viable option even in an extreme pandemic situation with less than 0.5 years increase in payback period, and the government can still provide a stimulus for investing in green energy by implementing net-metering policies on a larger scale.

Recombinant expression and biophysical characterization of Mrt4 protein that involved in mRNA turnover and ribosome assembly from Saccharomyces cerevisiae

The mRNA turnover and ribosome assembly are facilitated by Mrt4 protein from Saccharomyces cerevisiae. In present study, we are reporting the cloning, expression and homogeneous purification of recombinant Mrt4. Mrt4 is a 236-amino-acid-long nuclear protein that plays a very crucial role in mRNA turnover and ribosome assembly during the translation process. mrt4 gene was amplified by polymerase chain reaction and cloned in expression vector pET23a (+) under the bacteriophage T7-inducible promoter and lac operator. Furthermore, protein was purified to homogeneity using immobilized metal affinity chromatography (IMAC) and its homogeneous purification was further validated by immunoblotting with anti-His antibody. The far-UV CD spectra represent that Mrt4 has a typical α helix with characteristic negative minima at 222 and 208 nm. At physiological pH, the fluorescence spectra and CD spectra showed properly folded tertiary and secondary structures of Mrt4, respectively. Saccharomyces Mrt4 protein possesses putative bipartite NLS (nuclear localization signal) at the N-terminal part followed by two well-conserved domains, rRNA-binding domains and translation factor (TF) binding domain. PIPSA analysis evaluates electrostatic interaction properties of proteins and concluded that Mrt4 protein can be used as a fingerprint for classifying Mrt4-like mRNA turnover protein from various species. The availability of an ample amount of protein may help in its biochemical and biophysical characterization, crystallization and identification of new interacting partners of Mrt4.

Effect of garlic supplementation on zootechnical performance and hepato-renal functions in nitrate-treated rabbits

The effect of garlic supplementation on zootechnical performance and hepato-renal functions of rabbits exposed to experimental nitrate poisoning was evaluated. Adult male 6-8 week-old albino rabbits (n= 24) were randomly divided into four groups (A - D) and subjected to nitrate intoxication through the oral administration of sodium nitrate solution at 2 ml/kg bodyweight per day for 40 days. Group A was a control that received no treatment except sodium nitrate. Rabbits in groups B and C were treated with 1% methylene blue solution (2 mg/kg bodyweight per day) and aqueous garlic extract (500 mg/kg bodyweight per day) through intraperitoneal and oral routes, respectively. Rabbits in group D were treated with both 1% methylene blue solution (2 mg/kg bodyweight per day, intraperitoneally) and aqueous garlic extract (500 mg/kg bodyweight per day, orally). On completion of the treatment period, the groups were compared in growth performance, biochemical profile and histopathological changes of hepato-renal tissues. Although the total feed consumption of the groups remained comparable, Group C showed relatively better weight gain and feed conversion ratio (FCR). Likewise, garlic extract significantly increased the serum bilirubin concentration and reduced the level of other biochemical attributes in comparison with control animals. The hepatic and renal tissues of Groups C and D remained normal, whereas those of the control group exhibited distinct histopathological alterations. It was concluded that garlic supplementation ameliorated the deleterious effects of nitrate intoxication on production performance and hepato-renal functions of rabbits.

pH and alcohol induced structural transition in Ntf2 a nuclear transport factor of Saccharomyces cerevisiae

Ntf2 is a nuclear envelope protein, which play a pivotal role in nucleocytoplasmic transport and mediates the nuclear import of RanGDP. It interacts with various nucleoporins along with Ran-GDP and part of a multicomponent system that assembles at the nuclear pore complex (NCP) during nuclear import. Here, we have described the biophysical characterization of Ntf2 from Saccharomyces cerevisiae. Recombinant Ntf2 showed increment in the β-sheet content as well as decrement in the α-helix content from pH-7.0 to pH-4.0. A subsequent decrease in the pH led to increment in the α-helical content along with decrement in β-sheet content. Intrinsic fluorescence studies demonstrated the unfolding of the protein below physiological pH. Ntf2 showed stabilization as well as phenomenal phase transition (β sheet to α helix) by increase in alcohol concentration from 10% to 70%. Further increase in alcohol concentration (90%) resulted in residual secondary structure in Ntf2 protein. Presence of ammonium sulfate also stabilizes the secondary structure of Ntf2 protein. The structural characterization reveals the flexibility and the stability of Ntf2 at various conditions. These structural alterations in Ntf2 protein probably occurs in the course of nucleocytoplasmic transport when it interacts with other proteins moving towards its final destination.

Untapped renewable energy potential of crop residues in Pakistan: Challenges and future directions

Sustainability in power generation mainly depends on the transition from fossils to sustainable energy resources. Biomass from the crop residue has huge potential for renewable power generation, but it is still not utilized to its full potential. This study presents a comprehensive methodology to evaluate and forecast the current and future availability of selective crop residue to generate renewable energy. A forecast model incorporating historical trends in the crop yield has been developed in MATLAB and implemented for crop residue based biomass resource assessment of five primary crops (wheat straw, rice husk, rice straw, cotton straw, corn stover, and bagasse) in order to estimate the energy generation potential for Pakistan from 2018 till 2035. It was found that about 40 million tonnes of crop residue was available in Pakistan for power generation in the year 2018 considering a residue removal (availability) factor of 50%. This translates to an estimated potential of about 11,000 MW of electricity generation capacity using crop residue derived biomass for 2018. This capacity is predicted to gradually increase up to 16,000 MW by the year 2035 based on the trends in the growth of crop production since 2001. The suitability of a potential region for the installation of 100 MW biomass-fired power plants was also assessed by calculating crop residue density and an equivalent collection radius (R_e) of 50 km (km). Punjab province of Pakistan, being an agricultural province, with relatively better road infrastructure can sustain crop residue based power plants of up to 7000 MW cumulative capacity at various locations. The challenges, such as economic, logistics, regulatory and political barriers, in generating renewable energy from biomass along with their potential solutions were also discussed. The study also provides a baseline for future research to evaluate and forecast the growth in bio-power generation potential of any biomass resource in a region based on crop yield and area of the region.

Chaperone Like Attributes of Biogenic Fluorescent Gold Nanoparticles: Potential to Alleviate Toxicity Induced by Intermediate State Fibrils Against Neuroblastoma Cells

In general, neurodegenerative disorders have a great deal of correlation with the misfolded as well as aggregated forms of protein-based macromolecules. Among various species formed during the aggregation process, protein oligomers have been classified as most toxic entities against several types of living cells. A series of chemicals have been developed to inhibit protein aggregation as a measure to regulate neurodegenerative diseases. Recently, various classes of nanoparticles have also been reported to inhibit protein aggregation. In the present study, we synthesized fluorescent gold nanoparticles (B-AuNPs) employing Olax scandens leaf extract. Next, an in vitro study was performed to assess the effect of as-synthesized B-AuNPs on the aggregation behavior of the ovalbumin (OVA) and other related model proteins. We performed an extensive study to elucidate anti-amyloidogenic properties of nano-sized entities and established that small-sized B-AuNPs manifest chaperone potential against protein aggregation. Further, we exploited as-synthesized B-AuNPs as a mean to prevent protein aggregation mediated toxicity in neuroblastoma cells.

Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7

Nanoparticle-mediated bio-sensing promoted the development of novel sensors in the front of medical diagnosis. In the present study, we have generated and examined the potential of titanium dioxide (TiO₂) crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA. The performance of this novel DNA biosensor was measured the electrical current response using a picoammeter. The sensor surface was chemically functionalized with (3-aminopropyl) triethoxysilane (APTES) to provide contact between the organic and inorganic surfaces of a single-stranded DNA probe and TiO₂ nanoparticles while maintaining the sensing system’s physical characteristics. The complement of the target DNA of E. coli O157:H7 to the carboxylate-probe DNA could be translated into electrical signals and confirmed by the increased conductivity in the current-to-voltage curves. The specificity experiments indicate that the biosensor can discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. After duplex formation, the complementary target sequence can be quantified over a wide range with a detection limit of 1.0 x 10^-13M. With target DNA from the lysed E. coli O157:H7, we could attain similar sensitivity. Stability of DNA immobilized surface was calculated with the relative standard deviation (4.6%), displayed the retaining with 99% of its original response current until 6 months. This high-performance interdigitated DNA biosensor with high sensitivity, stability and non-fouling on a novel sensing platform is suitable for a wide range of biomolecular interactive analyses.

Low Temperature Annealed Zinc Oxide Nanostructured Thin Film-Based Transducers: Characterization for Sensing Applications

The performance of sensing surfaces highly relies on nanostructures to enhance their sensitivity and specificity. Herein, nanostructured zinc oxide (ZnO) thin films of various thicknesses were coated on glass and p-type silicon substrates using a sol-gel spin-coating technique. The deposited films were characterized for morphological, structural, and optoelectronic properties by high-resolution measurements. X-ray diffraction analyses revealed that the deposited films have a c-axis orientation and display peaks that refer to ZnO, which exhibits a hexagonal structure with a preferable plane orientation (002). The thicknesses of ZnO thin films prepared using 1, 3, 5, and 7 cycles were measured to be 40, 60, 100, and 200 nm, respectively. The increment in grain size of the thin film from 21 to 52 nm was noticed, when its thickness was increased from 40 to 200 nm, whereas the band gap value decreased from 3.282 to 3.268 eV. Band gap value of ZnO thin film with thickness of 200 nm at pH ranging from 2 to 10 reduces from 3.263eV to 3.200 eV. Furthermore, to evaluate the transducing capacity of the ZnO nanostructure, the refractive index, optoelectric constant, and bulk modulus were analyzed and correlated. The highest thickness (200 nm) of ZnO film, embedded with an interdigitated electrode that behaves as a pH-sensing electrode, could sense pH variations in the range of 2-10. It showed a highly sensitive response of 444 μAmM^-1cm^-2 with a linear regression of R² =0.9304. The measured sensitivity of the developed device for pH per unit is 3.72μA/pH.

Detection of Viruses in Sweetpotato from Honduras and Guatemala Augmented by Deep-Sequencing of Small-RNAs

Sweetpotato (Ipomoea batatas) plants become infected with over 30 RNA or DNA viruses in different parts of the world but little is known about viruses infecting sweetpotato crops in Central America, the center of sweetpotato domestication. Small-RNA deep-sequencing (SRDS) analysis was used to detect viruses in sweetpotato in Honduras and Guatemala, which detected Sweet potato feathery mottle virus strain RC and Sweet potato virus C (Potyvirus spp.), Sweet potato chlorotic stunt virus strain WA (SPCSV-WA; Crinivirus sp.), Sweet potato leaf curl Georgia virus (Begomovirus sp.), and Sweet potato pakakuy virus strain B (synonym: Sweet potato badnavirus B). Results were confirmed by polymerase chain reaction and sequencing of the amplicons. Four viruses were detected in a sweetpotato sample from the Galapagos Islands. Serological assays available to two of the five viruses gave results consistent with those obtained by SRDS, and were negative for six additional sweetpotato viruses tested. Plants coinfected with SPCSV-WA and one to two other viruses displayed severe foliar symptoms of epinasty and leaf malformation, purpling, vein banding, or chlorosis. The results suggest that SRDS is suitable for use as a universal, robust, and reliable method for detection of plant viruses, and especially useful for determining virus infections in crops infected with a wide range of unrelated viruses.

Development of swine-specific DNA markers for biosensor-based halal authentication

The pig (Sus scrofa) mitochondrial genome was targeted to design short (15-30 nucleotides) DNA markers that would be suitable for biosensor-based hybridization detection of target DNA. Short DNA markers are reported to survive harsh conditions in which longer ones are degraded into smaller fragments. The whole swine mitochondrial-genome was in silico digested with AluI restriction enzyme. Among 66 AluI fragments, five were selected as potential markers because of their convenient lengths, high degree of interspecies polymorphism and intraspecies conservatism. These were confirmed by NCBI blast analysis and ClustalW alignment analysis with 11 different meat-providing animal and fish species. Finally, we integrated a tetramethyl rhodamine-labeled 18-nucleotide AluI fragment into a 3-nm diameter citrate-tannate coated gold nanoparticle to develop a swine-specific hybrid nanobioprobe for the determination of pork adulteration in 2.5-h autoclaved pork-beef binary mixtures. This hybrid probe detected as low as 1% pork in deliberately contaminated autoclaved pork-beef binary mixtures and no cross-species detection was recorded, demonstrating the feasibility of this type of probe for biosensor-based detection of pork adulteration of halal and kosher foods.

Computerized stereotactic brain biopsies: an experience of 15 patients at Ayub Teaching Hospital

BACKGROUND

Deep seated lesions of the brain cannot be approached by conventional neurosurgical approach stereotactic system offers minimally invasive and accurate approach to such lesions. This study was carried out with an objective to determine the safety, efficacy and diagnostic yield of stereotactic biopsies of brain lesions using Brown-Roberts-Wells (BRW) system.

METHODS

This study was carried out in patients with intracranial lesions at Ayub teaching hospital Abbottabad from September 1999 to October 2003. Suitable patients with intra cranial lesions underwent computerized stereo tactic biopsy with BRW system. Tissue specimens were analyzed in histopathology department of the Ayub Medical College and results were obtained. Data was analyzed via computer software SPSS 8.0 version for windows.

RESULTS

Fifteen patients were selected for stereotactic brain biopsy. Age ranged from 15 years to 54 years. Among them 09 (60%) were male and 06 (40%) were female patients. Out come of the procedure was highly promising in terms of safety and positive diagnostic yield in 14 patients (93.3%), and histopathalogical validity of results (93.3%). Only one patient suffered mild neurological deficit (6.7%), one patient had inconclusive tissue diagnosis and invalid result (6.7%). biopsy proven lesion was astrocytoma in 04 patients (26.7%), anaplastic astrocytoma in 04 (26.7%), gliomatosis in 02 (13.3%), tuberculomas in 03 (20.0%). metastatic adenocarcinomas in 01 (6.7%) and lymphoma in 01(6.7%).

CONCLUSIONS

We conclude that computerized stereotactic brain biopsy is safe and effective procedure with a high diagnostic yield at our center.

Initial-rate method for the determination of pantoprazole in pharmaceutical formulations using 1-fluoro 2,4-dinitrobenzene

A simple and selective kinetic spectrophotometric method for the determination of pantoprazole in pharmaceutical preparations is described. The procedure is based upon a kinetic investigation of the reaction of the drug with 1-fluoro-2,4-dinitrobenzene in DMSO at room temperature. The absorbance of the coloured product was measured at 420 nm. The plot of the logarithm of the initial rate of the reaction vs. the logarithm of molar concentration of pantoprazole is linear over the range 10-20 microg x ml(-1). The procedure retains its accuracy in the presence of a large excess of its degradate, sulfenic acid, which is prepared by degradating the pure drug in borate buffer of pH 8 at room temperature for seven days. The results are validated statistically and through recovery studies. The method has been successfully applied to the determination of pantoprazole in commercial tablets. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.