Improved Stabilities of Immobilized Glucoamylase on Functionalized Mesoporous Silica Synthesised using Decane as Swelling Agent

Ordered mesoporous silica, with high porosity was used to immobilize glucoamylase via adsorption and covalent binding. Immobilization of glucoamylase within mesoporous silica was successfully achieved, resulting in catalytically high efficiency during starch hydrolysis. In this study, mesoporous silica was functionalized by co-condensation of tetraethoxysilane (TEOS) with organosilane (3-aminopropyl) triethoxysilane (APTES) in a wide range of molar ratios of APTES: TEOS in the presence of triblock copolymer P123 under acidic hydrothermal conditions. The prepared materials were characterized by Small angle XRD, Nitrogen adsorption – desorption and 29Si MAS solid state NMR. N2 desorption studies showed that pore size distribution decreases due to pore blockage after functionalization and enzyme immobilization. Small angle XRD and 29Si MAS NMR study reveals mesophase formation and Si environment of the materials. The main aim of our work was to study the catalytical activity, effect of pH, temperature storage stability and reusability of covalently bound glucoamylase on mesoporous silica support. The result shows that the stability of enzyme can be enhanced by immobilization.  © 2013 BCREC UNDIP. All rights reservedReceived: 3rd December 2012; Revised: 4th April 2013; Accepted: 20th April 2013[How to Cite: George, R., Gopinath, S., Sugunan, S. (2013). Improved Stabilities of Immobilized Glucoamyl-ase on Functionalized Mesoporous Silica Synthesized using Decane as Swelling Agent. Bulletin of Chemical Reaction Engineering &amp; Catalysis, 8 (1): 70-76. (doi:10.9767/bcrec.8.1.4208.70-76)][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4208.70-76] | View in  | </p

Longitudinal trial of smart-phone based social media applications for remote monitoring of cancer patients in the context of a LMIC: compliance, satisfaction, and cost-benefit analysis

The cancer burden is expected to reach 20 million new cases annually in low and middle-income countries (LMICs) by 2025. Few estimates suggest that thyroid cancer could become the third most common cancer diagnosed in women by 2019. Health care services need to gear up to provide close clinical follow-up care for patients especially in LMICs where there is already a shortage of healthcare personnel. We conducted this study to assess the effect of remote monitoring using tele-follow up on compliance, satisfaction and economic benefit. Participants were recruited to traditional hospital follow-up (consultation, clinical examination, and investigations as per hospital policy) or tele-follow up based on social media. Outcomes included information needs, participants’ compliance, and satisfaction, post-op complications, clinical investigations ordered. A total of 64 patients with thyroid cancer were recruited- 24 in hospital follow up group and 40 in the remote monitoring group. There were no significant differences between groups regarding satisfaction with information received. Responses were significantly more positive in the social media group, with a higher percentage reporting “very satisfied”. Wound evaluation through tele-follow up was on par with OPD follow up. If all of these 40 patients would have come to our OPD follow-up, they would have travelled on an average of 930 kms per patient. This study shows that social media is a practical tool in follow-up of cancer patients in LMICs where traditional telemedicine tools are restricted and conventional follow-up is economically challenging to patients. It also ensures compliance which is a major issue with conventional follow-up due to poor infrastructure

Electrospun Electroluminescent CsPbBr3 Fibers as Flexible Perovskite Networks for Light‐Emitting Application

Thin-film perovskite light-emitting diodes have gained increasing attention in the last 6 years. With the possibility to process the emitting layer from solution, the way for 1D morphology of the semiconductor for flexible devices is paved. Herein, for the first time single-step fabrication of CsPbBr3@PVP nanofibers in a customized electrospinning process performed under ambient conditions from a water-based precursor solution is reported. The water-based approach allows the incorporation of a conductive polymer into the compound fiber by blending the perovskite precursor ink with commercially available PEDOT:PSS dispersion. The results demonstrate electrospun fiber mats which are stable at ambient conditions for at least 5 months and can be utilized in electroluminescence devices. Photoluminescence studies on the perovskite fibers reveal a blueshift of the emission peak compared to thin films possibly due to the generation of nanocrystals of ≈12 nm by in situ nanocrystal pinning as confirmed by transmission electron microscopy. A proof-of-concept electrically pumped light-emitting device is built with the obtained fiber mat. The perovskite nanofibers offer promising applications in flexible and stretchable optoelectronics.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Universität zu Köln http://dx.doi.org/10.13039/501100008001Peer Reviewe

Neurologic phenotypes associated with COL4A1/2 mutations

Objective: To characterize the neurologic phenotypes associated with COL4A1/2 mutations and to seek genotype–phenotype correlation. Methods: We analyzed clinical, EEG, and neuroimaging data of 44 new and 55 previously reported patients with COL4A1/COL4A2 mutations. Results: Childhood-onset focal seizures, frequently complicated by status epilepticus and resistance to antiepileptic drugs, was the most common phenotype. EEG typically showed focal epileptiform discharges in the context of other abnormalities, including generalized sharp waves or slowing. In 46.4% of new patients with focal seizures, porencephalic cysts on brain MRI colocalized with the area of the focal epileptiform discharges. In patients with porencephalic cysts, brain MRI frequently also showed extensive white matter abnormalities, consistent with the finding of diffuse cerebral disturbance on EEG. Notably, we also identified a subgroup of patients with epilepsy as their main clinical feature, in which brain MRI showed nonspecific findings, in particular periventricular leukoencephalopathy and ventricular asymmetry. Analysis of 15 pedigrees suggested a worsening of the severity of clinical phenotype in succeeding generations, particularly when maternally inherited. Mutations associated with epilepsy were spread across COL4A1 and a clear genotype–phenotype correlation did not emerge. Conclusion: COL4A1/COL4A2 mutations typically cause a severe neurologic condition and a broader spectrum of milder phenotypes, in which epilepsy is the predominant feature. Early identification of patients carrying COL4A1/COL4A2 mutations may have important clinical consequences, while for research efforts, omission from large-scale epilepsy sequencing studies of individuals with abnormalities on brain MRI may generate misleading estimates of the genetic contribution to the epilepsies overall

Wound dressings for a proteolytic-rich environment

Wound dressings have experienced continuous and significant changes over the years based on the knowledge of the biochemical events associated with chronic wounds. The development goes from natural materials used to just cover and conceal the wound to interactive materials that can facilitate the healing process, addressing specific issues in non-healing wounds. These new types of dressings often relate with the proteolytic wound environment and the bacteria load to enhance the healing. Recently, the wound dressing research is focusing on the replacement of synthetic polymers by natural protein materials to delivery bioactive agents to the wounds. This article provides an overview on the novel protein-based wound dressings such as silk fibroin keratin and elastin. The improved properties of these dressings, like the release of antibiotics and growth factors, are discussed. The different types of wounds and the effective parameters of healing process will be reviewed

Efficacy of Quasi Agro Binding Fibre on the Hybrid Composite Used in Advance Application

The choice for natural fibre obtained from agricultural products is on the rise due to its solution to eco-friendly, environmental and improved mechanical properties concerns. Its abundant availability, low cost, emission reduction and adaptability to base material for composite make it a prime material for selection. This review explores diverse perspectives to the future trend of agro fibre in terms of the thermo-mechanical properties as it applies to advanced application in building structures. It is important to investigate the ecofriendliness of the products of composites from fibres in agricultural wastes so as to achieve a green and sustainable environment. This will come to fore by the combined efforts of both researchers and feedback from building stakeholders

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Glucoamylase immobilized on montmorillonite: influence of nature of binding on surface properties of clay-support and activity of enzyme

Glucoamylase was immobilized on acid activated montmorillonite clay via two different procedures namely adsorption and covalent binding. The immobilized enzymes were characterized by XRD, NMR and N2 adsorption measurements and the activity of immobilized glucoamylase for starch hydrolysis was determined in a batch reactor. XRD shows intercalation of enzyme into the clay matrix during both immobilization procedures. Intercalation occurs via the side chains of the amino acid residues, the entire polypeptide backbone being situated at the periphery of the clay matrix. 27Al NMR studies revealed the different nature of interaction of enzyme with the support for both immobilization techniques. N2 adsorption measurements indicated a sharp drop in surface area and pore volume for the covalently bound glucoamylase that suggested severe pore blockage. Activity studies were performed in a batch reactor. The adsorbed and covalently bound glucoamylase retained 49% and 66% activity of the free enzyme respectively. They showed enhanced pH and thermal stabilities. The immobilized enzymes also followed Michaelis–Menten kinetics. Km was greater than the free enzyme that was attributed to an effect of immobilization. The immobilized preparations demonstrated increased reusability as well as storage stability.Cochin University of Science & Technolog

Acid activated montmorillonite: an efficient immobilization support for improving reusability, storage stability and operational stability of enzymes

Three enzymes, α-amylase, glucoamylase and invertase, were immobilized on acid activated montmorillonite K 10 via two independent techniques, adsorption and covalent binding. The immobilized enzymes were characterized by XRD, N2 adsorption measurements and 27Al MAS-NMR spectroscopy. The XRD patterns showed that all enzymes were intercalated into the clay inter-layer space. The entire protein backbone was situated at the periphery of the clay matrix. Intercalation occurred through the side chains of the amino acid residues. A decrease in surface area and pore volume upon immobilization supported this observation. The extent of intercalation was greater for the covalently bound systems. NMR data showed that tetrahedral Al species were involved during enzyme adsorption whereas octahedral Al was involved during covalent binding. The immobilized enzymes demonstrated enhanced storage stability. While the free enzymes lost all activity within a period of 10 days, the immobilized forms retained appreciable activity even after 30 days of storage. Reusability also improved upon immobilization. Here again, covalently bound enzymes exhibited better characteristics than their adsorbed counterparts. The immobilized enzymes could be successfully used continuously in the packed bed reactor for about 96 hours without much loss in activity. Immobilized glucoamylase demonstrated the best results.Cochin University of Science and Technolog