Construction and investigation of multi-enzyme immobilized matrix for the production of HFCS.

Enzymes are biological molecules that act as catalysts and speed up the biochemical reactions. The world's biotechnological ventures are development of enzyme productiveness, and advancement of novel techniques for thriving their shelf existence. Nowadays, the most burning questions in enzyme technology are how to improve the enzyme productivity and reuse them. The immobilization of enzymes provides an excellent scope to reuse the enzymes several times to increase productivity. The main aim of the present study is the establishment of an immobilized multi-enzyme bio-system engineering process for the production of High-fructose corn syrup (HFCS) with an industrial focus. In this study, multi-enzyme such as α-amylase, glucoamylase and glucose isomerase were immobilized in various support matrices like sodium alginate, sawdust, sugarcane bagasse, rice bran and combination of alginate with cellulosic materials. The activities of the immobilized multi-enzyme system for the production of HFCS from the starch solution were determined. The multi-enzyme immobilized in sodium alginate shows better fructose conversion than free enzyme. Among the support matrices, multi-enzyme immobilized in sawdust produced total 80.74 mg/mL of fructose from starch solution and it was able to be used in several production cycles. On the other hand, multi-enzyme immobilized in combination of sodium alginate and sawdust produced the maximum amount of fructose (total 84.82 mg/mL). The free enzyme produced 17.25 mg/mL of fructose from the starch solution in only a single cycle. In this study a new fixed bed immobilized multi-enzyme bioreactor system was developed for the production of HFCS directly from starch. This finding will create a new opportunity for the application of immobilized multi-enzyme systems in many sectors of industrial biotechnology.

Potential Use of Artificial Intelligence (AI) in Disaster Risk and Emergency Health Management: A Critical Appraisal on Environmental Health.

The risk evaluation of natural disasters is an obstacle to ensuring healthcare services during catastrophic events worldwide. Therefore, timely and appropriate environmental health risk evaluation is essential. In this study, we incorporated the information from databases such as PubMed, Google Scholar, and Scopus. We performed this study to explore the feasibility of using artificial intelligence (AI) in disaster risk and emergency health management. Natural disasters have some phenomenon that is bound to happen. So, we can use AI to inform healthcare authorities about environmental health risks and emergency medical management. The recent innovations in technology have created novel opportunities for improving healthcare services across the world. AI technology would be the backbone of the fourth industrial revolution because we are entering an AI-based world this decade. Therefore, we suggest the authorities consider this positive aspect of AI technology to minimize the disastrous outcomes of any catastrophic events.

Increase in conduction velocity in myelinated nerves due to stretch - An experimental verification.

Background: Based on published experimental evidence, a recent publication revealed an anomalous phenomenon in nerve conduction: for myelinated nerves the nerve conduction velocity (NCV) increases with stretch, which should have been the opposite according to existing concepts and theories since the diameter decreases on stretching. To resolve the anomaly, a new conduction mechanism for myelinated nerves was proposed based on physiological changes in the nodal region, introducing a new electrical resistance at the node. The earlier experimental measurements of NCV were performed on the ulnar nerve at different angles of flexion, focusing at the elbow region, but left some uncertainty for not reporting the lengths of nerve segments involved so that the magnitudes of stretch could not be estimated. Aims: The aim of the present study was to relate NCV of myelinated nerves with different magnitudes of stretch through careful measurements. Method: Essentially, we duplicated the earlier published NCV measurements on ulnar nerves at different angles of flexion but recording appropriate distances between nerve stimulation points on the skin carefully and assuming that the lengths of the underlying nerve segment undergoes the same percentages of changes as that on the skin outside. Results: We found that the percentage of nerve stretch across the elbow is directly proportional to the angle of flexion and that the percentage increase in NCV is directly proportional to the percentage increase in nerve stretch. Page's L Trend test also supported the above trends of changes through obtained p values. Discussion: Our experimental findings on myelinated nerves agree with those of some recent publications which measured changes in CV of single fibres, both myelinated and unmyelinated, on stretch. Analyzing all the observed results, we may infer that the new conduction mechanism based on the nodal resistance and proposed by the recent publication mentioned above is the most plausible one to explain the increase in CV with nerve stretch. Furthermore, interpreting the experimental results in the light of the new mechanism, we may suggest that the ulnar nerve at the forearm is always under a mild stretch, with slightly increased NCV of the myelinated nerves.

Pre-COVID-19 knowledge, attitude and practice among nurses towards infection prevention and control in Bangladesh: A hospital-based cross-sectional survey.

INTRODUCTION: Hospital-acquired infections endanger millions of lives around the world, and nurses play a vital role in the prevention of these infections. Knowledge of infection prevention and control (IPC) best practices among nurses is a prerequisite to maintaining standard precautions for the safety of patients. AIM: The study aims to assess knowledge, attitudes, and practices (KAP) towards IPC including associated factors among the nurses of a tertiary care hospital in Bangladesh. METHODS: We conducted this hospital-based cross-sectional study from October 2017 to June 2018 at Dhaka Medical College Hospital among 300 nurses working in all departments. We calculated three KAP scores for each participant reflecting their current state of knowledge and compliance towards IPC measures. Descriptive, bivariate and multivariable analyses were conducted to determine KAP scores among nurses and their associated factors. RESULTS: Average scores for knowledge, attitudes, and practices were 18.6, 5.4, and 15.5 (out of 26, 7, and 24), respectively. The study revealed that the majority (85.2%) of the nurses had a good to moderate level of knowledge, half (51%) of them showed positive attitudes, and only one fifth (17.1%) of the nurses displayed good practices in IPC. The respondents' age, education, monthly income and years of experience were found to have statistical associations with having moderate to adequate level of KAP scores. Aged and experienced nurses were found more likely to have poor knowledge and unfavorable attitude toward IPC practices. CONCLUSION: The majority of nurses had good IPC knowledge, but their practices did not reflect that knowledge. In particular, nurses needed to improve the proper IPC practice for better patient care and to protect themselves. Regular IPC training and practice monitoring can enhance the IPC practice among nurses.

Effects of osmotic pressure on the irreversible electroporation in giant lipid vesicles.

Irreversible electroporation (IRE) is a nonthermal tumor/cell ablation technique in which a series of high-voltage short pulses are used. As a new approach, we aimed to investigate the rupture of giant unilamellar vesicles (GUVs) using the IRE technique under different osmotic pressures (Π), and estimated the membrane tension due to Π. Two categories of GUVs were used in this study. One was prepared with a mixture of dioleoylphosphatidylglycerol (DOPG), dioleoylphosphatidylcholine (DOPC) and cholesterol (chol) for obtaining more biological relevance while other with a mixture of DOPG and DOPC, with specific molar ratios. We determined the rate constant (kp) of rupture of DOPG/DOPC/chol (46/39/15)-GUVs and DOPG/DOPC (40/60)-GUVs induced by constant electric tension (σc) under different Π. The σc dependent kp values were fitted with a theoretical equation, and the corresponding membrane tension (σoseq) at swelling equilibrium under Π was estimated. The estimated membrane tension agreed well with the theoretical calculation within the experimental error. Interestingly, the values of σoseq were almost same for both types of synthesized GUVs under same osmotic pressure. We also examined the sucrose leakage, due to large osmotic pressure-induced pore formation, from the inside of DOPG/DOPC/chol(46/39/15)-GUVs. The estimated membrane tension due to large Π at which sucrose leaked out was very similar to the electric tension at which GUVs were ruptured without Π. We explained the σc and Π induced pore formation in the lipid membranes of GUVs.

Electrostatic effects on the electrical tension-induced irreversible pore formation in giant unilamellar vesicles.

Irreversible electroporation (IRE) is a new technique in which a series of short pulses with high frequency electrical energy is applied on the targeted regions of cells or vesicles for their destruction or rupture formation. IRE induces lateral tension in the membranes of vesicles. We have investigated the electrostatic interaction effects on the constant electrical tension-induced rate constant of irreversible pore formation in the membranes of giant unilamellar vesicles (GUVs). The electrostatic interaction has been varied by changing the salt concentration in buffer and the surface charge density of membranes. The membranes of GUVs are synthesized by a mixture of negatively charged lipid dioleoylphosphatidylglycerol (DOPG) and neutral lipid dioleoylphosphatidylcholine (DOPC) using the natural swelling method. The rate constant of pore formation increases with the decrease of salt concentration in buffer along with the increase of surface charge density of membranes. The tension dependent probability of pore formation and the rate constant of pore formation are fitted to the theoretical equation, and obtained the line tension of membranes. The decrease in energy barrier of a prepore due to electrostatic interaction is the key factor causing an increase of rate constant of pore formation.

Knowledge and attitudes associated with menopause among women aged 45 to 60 years: a pilot study among rural and urban women in Bangladesh.

OBJECTIVE: To assess knowledge and attitudes associated with the menopause transition among women in Bangladesh. METHODS: A cross-sectional survey was conducted among women (age range 45-60 y), 160 participants were selected from both urban and rural settings using a systematic sampling procedure. We used face-to-face interview techniques employing a semistructured questionnaire. Bivariate and multivariate regression analyses were done to assess the associated factors. RESULTS: Around one-fourth (23%) of the participants did not have a basic understanding about symptoms of menopause. Knowledge about menopause increased proportionately with higher education levels (primary education, risk ratio [RR] = 3.91, 95% confidence interval [CI] = 0.66-22.92; secondary education, RR = 6.10, 95% CI = 1.26-29.41; higher education, RR = 6.74, 95% CI = 1.33-34) and was more common among urban than rural women (P = 0.001). In addition, women who were service holders had greater knowledge about menopause compared with women who worked in the home (RR = 8.67, 95% CI = 1.94-38.58). Most of the women (96%) suffered from different kinds of depression during the menopause transition. Key barriers to gaining knowledge about menopause included access to information (63%), social stigma (57%), and shame (52%). CONCLUSIONS: Menopause is a neglected issue in Bangladesh. Accurate and appropriate information regarding premenopause and menopause can help women cope with this life transition. Social and familial support may also play a role in minimizing isolation and depression. Public health messaging to increase awareness and knowledge about menopause should be undertaken to overcome the stigma and shame associated with menopause in Bangladesh. : Video Summary:http://links.lww.com/MENO/A556.

Video Summary:http://links.lww.com/MENO/A556.

Use of Target-Specific Liposome and Magnetic Nanoparticle Conjugation for the Amplified Detection of Norovirus.

Viral diseases are one of the most life-threatening diseases as they can erupt unpredictably and spread rapidly in any medium with a very small number of particles. Therefore, the key for lethal virus detection should be highly sensitive in the early-stage detection, which can help increase the chance of survival. Amplification of the detecting signal is one of the most promising mechanisms for the detection of low-concentration analytes. A proper amplification can develop such a kind of system where a small number of particles can produce intense signals for a prominent detection. Keeping this in mind, in this report, we have presented a fluorometric method to detect norovirus (NoV) by a newly developed fluorophore-labeled liposome and a magnetically modified Fe3O4 combined system. Homogeneously distributed amine-functionalized liposomes have been constructed filled with a strong fluorophore of calcein. Simultaneously, (3-aminopropyl)-triethoxysilane (APTES)-functionalized Fe3O4 nanoparticles are also synthesized by the standard silanization process, and these two separately synthesized nanoparticles were functionalized with an antibody to achieve specificity. The Fe3O4 and calcein-liposome system has been applied for NoV detection, which was magnetically separated from the analyte medium and then externally burst to release the fluorophores from the core of the liposome. The easiness, rapidity, and sensitivity in a wide linear range can offer a huge potential of this method in point-of-care diagnostics.

Elementary processes for the entry of cell-penetrating peptides into lipid bilayer vesicles and bacterial cells.

Cell-penetrating peptides (CPPs) can translocate across the plasma membrane of living eukaryotic cells and enter the cytosol without significantly affecting cell viability. Consequently, CPPs have been used for the intracellular delivery of biological cargo such as proteins and oligonucleotides. However, the mechanisms underlying the translocation of CPPs across the plasma membrane remain unclear. In this mini-review, we summarize the experimental results regarding the entry of CPPs into lipid bilayer vesicles obtained using three methods: the large unilamellar vesicle (LUV) suspension method, the giant unilamellar vesicle (GUV) suspension method, and the single GUV method. The advantages and disadvantages of these methods are also discussed. Experimental results to date clearly indicate that CPPs can translocate across lipid bilayers and enter the vesicle lumen. Three models for the mechanisms and pathways by which CPPs translocate across lipid bilayers are described: (A) through pores induced by CPPs, (B) through transient prepores, and (C) via formation of inverted micelles. Both the pathway of translocation and the efficiency of entry of CPPs depend on the lipid composition of the bilayer and the type of CPP. We also describe the interaction of CPPs with bacterial cells. Some CPPs have strong antimicrobial activities. There are two modes of action of CPPs on bacterial cells: CPPs can induce damage to the plasma membrane and thus increase permeability, or CPPs enter the cytosol of bacterial cells without damaging the plasma membrane. The information currently available on the elementary processes by which CPPs enter lipid bilayer vesicles and bacterial cells is valuable for elucidating the mechanisms of entry of CPPs into the cytosol of various eukaryotic cells.

Continuous detection of entry of cell-penetrating peptide transportan 10 into single vesicles.

Entry of cell-penetrating peptides (CPPs) into living cells by translocating across plasma membranes is an important physiological phenomenon. To elucidate the mechanism of the translocation of CPPs across lipid bilayers, it is essential to reveal its elementary processes. For this purpose, here, we have developed a new method for the continuous, quantitative detection of the entry of CPPs into giant unilamellar vesicles (GUVs), where we investigate the interaction of fluorescent probe-labeled CPPs with single GUVs containing large unilamellar vesicles (LUVs) and fluorescent probes in their lumens using confocal microscopy. Using this method, we investigated the interaction of carboxyfluorescein (CF)-labeled transportan 10 (CF-TP10) with single GUVs comprised of dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylcholine (DOPC) containing LUVs of the same membrane and Alexa Fluor 647 hydrazide (AF647) in their lumens. At low concentrations of CF-TP10, first the fluorescence intensity (FI) of the GUV membrane increased with time, and then after some lag time the FI of the GUV lumen due to CF-TP10 increased continuously with time without leakage of AF647. At higher concentrations of CF-TP10, after the FI of the GUV lumen due to CF-TP10 increased significantly, leakage of AF647 started. These results indicate that CF-TP10 entered the GUV lumen by translocating across the GUV membrane and then bound to the LUVs there without pore formation and that CF-TP10 concentration in the lumen increased with time. The rate of entry of CF-TP10 into GUV lumen increased with CF-TP10 concentration. We discussed the kinetics of entry of CF-TP10 into single GUVs.

Entry of a Six-Residue Antimicrobial Peptide Derived from Lactoferricin B into Single Vesicles and Escherichia coli Cells without Damaging their Membranes.

Lactoferricin B (LfcinB) and shorter versions of this peptide have antimicrobial activity. However, the elementary processes of interactions of these peptides with lipid membranes and bacteria are still not well understood. To elucidate the mechanism of their antimicrobial activity, we investigated the interactions of LfcinB (4-9) (its sequence of RRWQWR) with Escherichia coli cells and giant unilamellar vesicles (GUVs). LfcinB (4-9) and lissamine rhodamine B red-labeled LfcinB (4-9) (Rh-LfcinB (4-9)) did not induce an influx of a membrane-impermeant fluorescent probe, SYTOX green, from the outside of E. coli cells into their cytoplasm, indicating that no damage occurred in their plasma membrane. To examine the activity of LfcinB (4-9) to enter E. coli cytoplasm, we investigated the interaction of Rh-LfcinB (4-9) with single cells of E. coli containing calcein using confocal microscopy. We found that Rh-LfcinB (4-9) entered the cytoplasm without leakage of calcein. Next, we investigated the interactions of Rh-LfcinB (4-9) with single GUVs of dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylcholine (DOPC) mixtures containing a fluorescent probe, Alexa Fluor 647 hydrazide (AF647), using the single GUV method. The results indicate that Rh-LfcinB (4-9) outside the GUV translocated through the GUV membrane and entered its lumen without leakage of AF647. Interaction of Rh-LfcinB (4-9) with DNA increased its fluorescence intensity greatly. Therefore, we can conclude that Rh-LfcinB (4-9) can translocate across lipid membrane regions of the plasma membrane of E. coli cells to enter their cytoplasm without leakage of calcein and its antimicrobial activity is not due to damage of their plasma membranes.

Effects of Mechanical Properties of Lipid Bilayers on the Entry of Cell-Penetrating Peptides into Single Vesicles.

The translocation of cell-penetrating peptides (CPPs) through plasma membranes of living cells is an important physiological phenomenon in biomembranes. To reveal the mechanism underlying the translocation of a CPP, transportan 10 (TP10), through lipid bilayers, we examined the effects of the mechanical properties of lipid bilayers on the entry of carboxyfluorescein (CF)-labeled TP10 (CF-TP10) into a giant unilamellar vesicle (GUV) using the single GUV method. First, we examined the effect of lateral tension in membranes on the entry of CF-TP10 into single GUVs comprising a mixture of dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylcholine (DOPC) (2/8). CF-TP10 entered the GUV lumen before the membrane permeation of Alexa Fluor 647 hydrazide (AF647) from the GUV and thus before pore formation in the membrane. The fraction of entry of CF-TP10 before pore formation and the rate of membrane rupture increased with tension. The CF-TP10-induced fractional change in the membrane area increased continuously with time until membrane rupture, but it increased more slowly than did the CF-TP10 concentration in the GUV membrane. A high mole fraction of cholesterol inhibited the entry of CF-TP10 into single GUVs by suppressing the translocation of CF-TP10 from the external to the internal monolayer, although higher concentrations of CF-TP10 induced the formation of pores through which CF-TP10 rapidly translocated. Suppression of the translocation of CF-TP10 by cholesterol can be reasonably explained by the large line tension of a prepore. We discussed the role of mechanical properties in membranes on the entry of CF-TP10 into single GUVs and proposed a hypothesis of the mechanism that CF-TP10 translocates across a bilayer through transient hydrophilic prepores in the membrane.

Effects of Lipid Composition on the Entry of Cell-Penetrating Peptide Oligoarginine into Single Vesicles.

The cell-penetrating peptide R9, an oligoarginine comprising nine arginines, has been used to transport biological cargos into cells. However, the mechanisms underlying its translocation across membranes remain unclear. In this report, we investigated the entry of carboxyfluorescein (CF)-labeled R9 (CF-R9) into single giant unilamellar vesicles (GUVs) of various lipid compositions and the CF-R9-induced leakage of a fluorescent probe, Alexa Fluor 647 hydrazide (AF647), using a method developed recently by us. First, we investigated the interaction of CF-R9 with dioleoylphosphatidylglycerol (DOPG)/dioleoylphosphatidylcholine (DOPC) GUVs containing AF647 and small DOPG/DOPC vesicles. The fluorescence intensity of the GUV membrane due to CF-R9 (i.e., the rim intensity) increased with time to a steady-state value, and then the fluorescence intensity of the membranes of the small vesicles in the GUV lumen increased without leakage of AF647. This result indicates that CF-R9 entered the GUV lumen from the outside by translocating across the lipid membrane without forming pores through which AF647 could leak. The fraction of entry of CF-R9 at 6 min in the absence of pore formation, Pentry (6 min), increased with an increase in CF-R9 concentration, but the CF-R9 concentration in the lumen was low. We obtained similar results for dilauroyl-PG (DLPG)/ditridecanoyl-PC (DTPC) (2/8) GUVs. The values of Pentry (6 min) of CF-R9 for DLPG/DTPC (2/8) GUVs were larger than those obtained with DOPG/DOPC (2/8) GUVs at the same CF-R9 concentrations. In contrast, a high concentration of CF-R9 induced pores in DLPG/DTPC (4/6) GUVs through which CF-R9 entered the GUV lumen, so the CF-R9 concentration in the lumen was higher. However, CF-R9 could not enter DOPG/DOPC/cholesterol (2/6/4) GUVs. Analysis of the rim intensity showed that CF-R9 was located only in the outer monolayer of the DOPG/DOPC/cholesterol (2/6/4) GUVs. On the basis of analyses of these results, we discuss the elementary processes by which CF-R9 enters GUVs of various lipid compositions.

Prevalence and determinants of malnutrition among reproductive aged women of rural Bangladesh.

Malnutrition among the rural Bangladeshi women of reproductive age is still very high. This high prevalence attributes to a range of adverse health consequences on the women and their offspring. A total of 2341 women aged between 20 and 45 years residing in the study area were interviewed in this cross-sectional study. Information on socioeconomic variables, nutritional status, and pregnancy-related history was obtained using interviewer administered questionnaire. A total of 34% of the reproductive aged rural women suffer from malnutrition. A multivariate analysis shows association between malnutrition and monthly household income, history of taking oral contraceptive, current pregnancy status, and history of breastfeeding. The final regression model shows a statistically significant decreasing trend in malnutrition status with increasing income (P for trend <.001). The economic and health consequences of malnutrition in this group of women are enormous. National nutritional program should target this women group for any intervention with a special priority.

Rapid detection of early typhoid fever in endemic community children by the TUBEX O9-antibody test.

Typhoid remains a global public health problem, and quick accurate immunodiagnosis is needed. Here, we examined the performance of the 5-min TUBEX O9-antibody detection kit in 243 outpatients (mostly children and infants) in their first week of fever and 57 healthy subjects in the Bangladesh community. Based on culture results, TUBEX was 91.2% (31/34) sensitive and 82.3% (172/209) specific in febrile subjects. However, specificity was better in nonfebrile healthy subjects (89.5%, 51/57) or in febrile individuals who serologically had dengue fever (90.5%, 57/63), suggesting that some culture-negative febrile individuals could be truly typhoidal. These individuals were also positive in an anti-crude O9 enzyme-linked immunosorbent assay (ELISA) and the Widal test. Regression analysis of the TUBEX and ELISA results showed good concordance between them, better with the combined IgM-IgG ELISA than with IgM alone, suggesting that TUBEX detects IgM antibodies not necessarily by themselves, as previously reported, but with the help of IgG antibodies.