Screening biosurfactant-producing actinomycetes: Identification of Streptomyces sp. RP1 as a potent species for bioremediation.

This study aimed to isolate biosurfactant-producing and hydrocarbon-degrading actinomycetes from different soils using glycerol-asparagine and starch-casein media with an antifungal agent. The glycerol-asparagine agar exhibited the highest number of actinomycetes, with a white, low-opacity medium supporting pigment production and high growth. Biosurfactant analyses, such as drop collapse, oil displacement, emulsification, tributyrin agar test, and surface tension measurement, were conducted. Out of 25 positive isolates, seven could utilize both olive oil and black oil for biosurfactant production, and only isolate RP1 could produce biosurfactant when grown in constrained conditions with black oil as the sole carbon source and inducer, demonstrating in situ bioremediation potential. Isolate RP1 from oil-spilled garden soil is Gram-staining-positive with a distinct earthy odor, melanin formation, and white filamentous colonies. It has a molecular size of ~621 bp and 100% sequence similarity to many Streptomyces spp. Morphological, biochemical, and 16 S rRNA analysis confirmed it as Streptomyces sp. RP1, showing positive results in all screenings, including high emulsification activity against kerosene (27.2%) and engine oil (95.8%), oil displacement efficiency against crude oil (7.45 cm), and a significant reduction in surface tension (56.7 dynes/cm). Streptomyces sp. RP1 can utilize citrate as a carbon source, tolerate sodium chloride, resist lysozyme, degrade petroleum hydrocarbons, and produce biosurfactant at 37°C in a 15 mL medium culture, indicating great potential for bioremediation and various downstream industrial applications with optimization.

Robust memory humoral immune response to SARS-CoV-2 in the tonsils of adults and children.

Background: Adaptive humoral immunity against SARS-CoV-2 has mainly been evaluated in peripheral blood. Human secondary lymphoid tissues (such as tonsils) contain large numbers of plasma cells that secrete immunoglobulins at mucosal sites. Yet, the role of mucosal memory immunity induced by vaccines or natural infection against SARS-CoV-2 and its variants is not fully understood. Methods: Tonsillar mononuclear cells (TMNCs) from adults (n=10) and children (n=11) were isolated and stimulated using positive SARS-CoV-2 nasal swabs. We used endpoint enzyme-linked immunosorbent assays (ELISAs) for the measurement of anti-S1, -RBD, and -N IgG antibody levels and a pseudovirus microneutralization assay to assess neutralizing antibodies (nAbs) in paired serum and supernatants from stimulated TMNCs. Results: Strong systemic humoral response in previously SARS-CoV-2 infected and vaccinated adults and children was observed in accordance with the reported history of the participants. Interestingly, we found a significant increase in anti-RBD IgG (305 and 834 folds) and anti-S1 IgG (475 and 443 folds) in the stimulated TMNCs from adults and children, respectively, compared to unstimulated cells. Consistently, the stimulated TMNCs secreted higher levels of nAbs against the ancestral Wuhan strain and the Omicron BA.1 variant compared to unstimulated cells by several folds. This increase was seen in all participants including children with no known history of infection, suggesting that these participants might have been previously exposed to SARS-CoV-2 and that not all asymptomatic cases necessarily could be detected by serum antibodies. Furthermore, nAb levels against both strains were significantly correlated in adults (r=0.8788; p = 0.0008) and children (r = 0.7521; p = 0.0076), and they strongly correlated with S1 and RBD-specific IgG antibodies. Conclusion: Our results provide evidence for persistent mucosal humoral memory in tonsils from previously infected and/or vaccinated adults and children against recent and old variants upon re-exposure. They also highlight the importance of targeting mucosal sites with vaccines to help control infection at the primary sites and prevent potential breakthrough infections.

The Molecular Size of Bioengineered Oxygen Carriers Determines Tissue Oxygenation in a Hypercholesterolemia Guinea Pig Model of Hemorrhagic Shock and Resuscitation.

Polymerized human hemoglobin (PolyhHb) has shown promise in preclinical hemorrhagic shock settings. Different synthetic and purification schemes can control the size of PolyhHbs, yet research is lacking on the impact of polymerized hemoglobin size on tissue oxygenation following hemorrhage and resuscitation in specialized animal models that challenge their resuscitative capabilities. Pre-existing conditions that compromise the vasculature and end organs, such as the liver, may limit the effectiveness of resuscitation and exacerbate the toxicity of these molecules, which is an important but minimally explored therapeutic dimension. In this study, we compared the effective oxygen delivery of intermediate molecular weight PolyhHb (PolyhHb-B3; 500-750 kDa) to high molecular weight PolyhHb (PolyhHb-B4; 750 kDa-0.2 µm) for resuscitative effectiveness in guinea pig models subjected to hemorrhagic shock. We evaluated how the size of PolyhHb impacts hemodynamics and tissue oxygenation in normal guinea pigs and guinea pigs on an atherogenic diet. We observed that while PolyhHb-B3 and -B4 equivalently restore hemodynamic parameters of normal-dieted guinea pigs, high-fat-dieted guinea pigs resuscitated with PolyhHb-B4 have lower mean arterial pressures, impaired tissue oxygenation, and higher plasma lactate levels than those receiving PolyhHb-B3. We characterized the plasma of these animals following resuscitation and found that despite similar oxygen delivery kinetics, circulating PolyhHb-B3 and -B4 demonstrated a size-dependent increase in the plasma viscosity, consistent with impaired perfusion in the PolyhHb-B4 transfusion group. We conclude that intermediate-sized PolyhHbs (such as -B3) are ideal for further research given the effective resuscitation of hemorrhagic shock based on tissue oxygenation in hypercholesterolemic guinea pigs.

Extended Biosynthesis of Rhamnolipid by Immobilized Pseudomonas aeruginosa USM-AR2 Cells in a Fluidized Bed Bioreactor.

This study aims to evaluate rhamnolipid production by immobilized Pseudomonas aeruginosa USM-AR2 cells using waste cooking oil (WCO) as the carbon source. P. aeruginosa USM-AR2 cells were entrapped in polyvinyl alcohol (PVA)-alginate hydrogel beads. The performance of entrapped cells was compared with free cells in shake flasks before cultivation in a custom-designed fluidized bed reactor (FBR). A mass of 1 g wet cells entrapped in PVA-alginate hydrogel beads were successfully recycled 3 times in shake flasks at 200 rpm, producing between 0.66-1.34 g L-1 rhamnolipid after 120 h. Meanwhile, cultivation of entrapped cells in FBR with broth recirculation showed that the suitable hydrogel beads to medium ratio was 1:20 ratio at an aeration rate of 0.5 vvm, producing between 0.77 to 1.58 g L-1 rhamnolipid, degrading 8.67 to 20.93 g L-1 of waste cooking oil in 15 cycles of repeated batch cultivation. Entrapped P. aeruginosa USM-AR2 cells achieved a higher rhamnolipid production, by 1.03-fold during cycle 3 in shake flasks and 1.19-fold during cycle 11 in an FBR, compared to free cells. These results show that entrapment enables reusability of viable cells and maintains stability of rhamnolipid production throughout the extended cultivation, increasing cell tolerance to perturbations in fermentation conditions.

Biophysical Analysis and Preclinical Pharmacokinetics-Pharmacodynamics of Tangential Flow Filtration Fractionated Polymerized Human Hemoglobin as a Red Blood Cell Substitute.

Red blood cell (RBC) substitutes tested in late-phase clinical trials contained low-molecular-weight hemoglobin species (<500 kDa), resulting in vasoconstriction, hypertension, and oxidative tissue injury; therefore, contributing to poor clinical outcomes. This work aims to improve the safety profile of the RBC substitute, polymerized human hemoglobin (PolyhHb), via in vitro and in vivo screening of PolyhHb fractionated into four molecular weight brackets (50-300 kDa [PolyhHb-B1]; 100-500 kDa [PolyhHb-B2]; 500-750 kDa [PolyhHb-B3]; and 750 kDa to 0.2 µm [PolyhHb-B4]) using a two-stage tangential flow filtration purification process. Analysis showed that PolyhHb's oxygen affinity, and haptoglobin binding kinetics decreased with increasing bracket size. A 25% blood-for-PolyhHb exchange transfusion guinea pig model suggests that hypertension and tissue extravasation decreased with increasing bracket size. PolyhHb-B3 demonstrated extended circulatory pharmacokinetics, no renal tissue distribution, no aberrant blood pressure, or cardiac conduction effects, and may therefore be appropriate material for further evaluation.

Changes in Perception of Illness during Cardiac Rehabilitation Programme among Patients with Acute Coronary Syndrome: A Longitudinal Study.

Little is known about the changes in perception of illness among patients with the acute coronary syndrome (ACS) during cardiac rehabilitation programme (CRP). The purpose of this study is to determine changes in perception of illness with ACS patients during CRP to evaluate the association of patients' characteristics with the perception of illness at the end of Phase II of CRP. A descriptive longitudinal study was conducted among 450 patients who attended 8-weeks of Phase II CRP at 2 public hospitals in Malaysia and perception of illness was assessed using Brief Illness Perception Questionnaire (BIPQ). The assessment was conducted before Phase II (T0), during the 4th session (T1), and at the end of right after the 8th session (T2). One-way repeated measures of ANOVA analysed the changes of perception at T1 and T2 while logistic regression analysis evaluated the association of patients' characteristics with the perception of illness at T2. Perception of illness changed during and after CRP from T0 to T1, and T1 to T2 (p < 0.001). The patient viewed ACS as an illness that changed from being more acute to a chronic condition as the sessions progressed. Previous history of acute myocardial infarction (OR = 2.380, 95% CI 1.46, 5.49) and angioplasty intervention were both found to be associated with the perception of illness (OR = 3.857, 95% CI 1.55, 9.61). Perception of illness changed during CRP and these changes are associated with patients' previous history of cardiac events. Phase II can be viewed as the second window of opportunity for healthcare professionals to intervene early in modifying the perception of illness.

Contraceptive Use and the Associated Factors among Women of Reproductive Age in Jazan City, Saudi Arabia: A Cross-Sectional Survey.

The contraceptive use profile is poorly understood in some Gulf Arabian countries, including Saudi Arabia. The present study aimed to assess the knowledge, attitude, and practices related to contraceptive use among women of childbearing age in Jazan city, Saudi Arabia. An observational, analytical cross-sectional study was conducted among a random sample of 450 women in Jazan city. The data were obtained through personal interviews using a questionnaire that included questions on women's level of knowledge about contraception methods, their attitudes towards contraception methods, and their practices. Data were analyzed using descriptive and inferential statistics techniques using the SPSS program. The prevalence of ever having used contraceptives was significantly different according to age group, job status, children ever born, and the number of pregnancies (p < 0.05 for all). On the other hand, the prevalence of desire to use the contraceptives in the future was high, at 70.9%, with a 95% CI [66.5-74.9]. It differed significantly according to age group and job status (p < 0.05 for both). The most familiar and usable types of contraceptives were pills (36.3%) and intrauterine devices (24.4%). When asked their reasons for using contraceptives, 53.8% of participants cited child spacing and 21.8% improving child health. Logistic regression revealed that the use of contraception among women was more associated with the 20-34 age group [COR = 7.7, 95% CI = 4.4-13.5, p < 0.001] than the 15-24 age group. Having more than one pregnancy and having more than one child were also associated with increased use of contraceptive methods (p < 0.001 for both). These results indicate there is a high level of awareness about contraceptives, a positive attitude toward them, and good practices for the use of them among Saudi women in Jazan. More efforts are needed to improve women's awareness for better utilization of the available services.

Improved chemical and isotopic labeling of biomembranes in Bacillus subtilis by leveraging CRISPRi inhibition of beta-ketoacyl-ACP synthase (fabF).

Assessing the structure of living microbial cell membranes is a challenging analytical goal. The cell membrane is defined by its transverse structure, an approximately 5 nm-thick selectively permeable bilayer that serves many important cellular functions. Compositionally complex, dynamic, and organized in both the transverse and lateral dimensions, understanding the cell membrane structure-and the role that structure plays in cellular function, communication, and environmental sensing is an active scientific effort. Previously, we have devised a novel isotopic labeling approach for membrane lipids to enable direct in vivo structural studies of the cell membrane in the Gram-positive bacterium, Bacillus subtilis, using small-angle neutron scattering. This was accomplished through a genetic inhibition of fatty acid (FA) degradation (ΔfadN) and a chemical inhibition of FA biosynthesis using cerulenin, an irreversible inhibitor of type II fatty acid synthases. Here, we improve upon the previous system by introducing a dCas9/sgRNA-fabF complex that blocks transcription of the essential fabF gene when under xylose induction. This leads to greater sensitivity to cerulenin in the mutant strain (JEBS102) and more robust cell growth when supplementary FAs are introduced to the culture medium. A subtle change in FA uptake is noted when compared to the prior labeling strategy. This is seen in the gas chromatography/mass spectrometry (GC/MS) data as a higher ratio of n16:0 to a15:0, and manifests in an apparent increase in the membrane thickness determined via neutron scattering. This represents an improved method of isotopic labeling for the cell membrane of Bacillus subtilis; enabling improved investigations of cellular uptake and utilization of FAs, cell membrane structure and organization as a phenotypic response to metabolic and environmental changes.

A Pituitary Abscess Caused by Morganella morganii: A Case Report.

BACKGROUND Pituitary abscess (PA) is a rare pituitary lesion accounting for less than 1% of all pituitary diseases and is associated with high mortality rates. The non-specific clinical symptoms and radiological features preclude accurate diagnosis of the disease. Hence, surgical intervention is still considered the criterion standard method for PA diagnosis. Most PAs occur as a primary disease or due to complications such as surgery, sepsis, and adjacent inflamed lesions. CASE REPORT A 53-year-old man presented to the Emergency Department with a headache associated with nausea, vomiting, and constipation. The patient had no visual disturbances, polyuria, polydipsia, nocturia, or abnormal discharges. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large suprasellar mass. The patient underwent left-side trans-nasal transsphenoidal microscopic surgery for mass removal. An abscess with discharge was noticed and sent for microbiological evaluation, revealing an infection with a commensal enteric bacterium that rarely causes nosocomial infection, known as Morganella morganii. The patient was discharged after completing the intravenous antibiotic course and was given oral antibiotics. CONCLUSIONS Pituitary abscess is a rare pituitary lesion. However, taking the history of recent meningitis, sinusitis, and/or surgery may help to reach an early diagnosis, prompt surgical intervention, and vital therapeutic steps to reduce mortality rates and improve patient's outcomes. PA should always be considered when patients demonstrate signs of pituitary dysfunction associated with signs of infection. Furthermore, antibiotics should be administered immediately once the PA case is confirmed and should last for at least 6 weeks postoperatively.

Mechanistic Insight into the Enzymatic Inhibition of ß-Amyrin against Mycobacterial Rv1636: In Silico and In Vitro Approaches.

Mycobacterium tuberculosis has seen tremendous success as it has developed defenses to reside in host alveoli despite various host-related stress circumstances. Rv1636 is a universal stress protein contributing to mycobacterial survival in different host-derived stress conditions. Both ATP and cAMP can be bound with the Rv1636, and their binding actions are independent of one another. ß-Amyrin, a triterpenoid compound, is abundant in medicinal plants and has many pharmacological properties and broad therapeutic potential. The current study uses biochemical, biophysical, and computational methods to define the binding of Rv1636 with ß-Amyrin. A substantial interaction between ß-Amyrin and Rv1636 was discovered by molecular docking studies, which helped decipher the critical residues involved in the binding process. VAL60 is a crucial residue found in the complexes of both Rv1636_ß-Amyrin and Rv1636-ATP. Additionally, the Rv1636_ß-Amyrin complex was shown to be stable by molecular dynamics simulation studies (MD), with minimal changes observed during the simulation. In silico observations were further complemented by in vitro assays. Successful cloning, expression, and purification of Rv1636 were accomplished using Ni-NTA affinity chromatography. The results of the ATPase activity assay indicated that Rv1636's ATPase activity was inhibited in the presence of various ß-Amyrin concentrations. Additionally, circular dichroism spectroscopy (CD) was used to examine modifications to Rv1636 secondary structure upon binding of ß-Amyrin. Finally, isothermal titration calorimetry (ITC) advocated spontaneous binding of ß-Amyrin with Rv1636 elucidating the thermodynamics of the Rv1636_ß-Amyrin complex. Thus, the study establishes that ß-Amyrin binds to Rv1636 with a significant affinity forming a stable complex and inhibiting its ATPase activity. The present study suggests that ß-Amyrin might affect the functioning of Rv1636, which makes the bacterium vulnerable to different stress conditions.

Exploring Social Support for Women Coping with a Cardiac Rehabilitation Programme after Acute Coronary Syndrome: A Systematic Review of Qualitative Studies.

OBJECTIVE: Female sex is a major barrier to completing a programme of cardiac rehabilitation (CR) after acute coronary syndrome (ACS). Women require significant social support to promote compliance and the ability to cope with CR programme attendance. The aim of this systematic review of qualitative studies was to explore social support among women coping with CR programme attendance at phase II CRP is 3 months after their cardiac event. METHODS: Articles were searched through CINAHL (Cumulative Index and Allied Health Literature), Science Direct and PubMed databases using the following terms: "women", "acute coronary syndrome", "coping", "social support" and "cardiac rehabilitation". RESULTS: A total of 6 articles were selected based on eligibility criteria. Thematic analysis was used to analyse the data using line to line coding into descriptive themes, interpreting further to generate new insights. The 3 most common themes regarding social support for women attending the CR programme were: family support, female as the primary caregiver in the family, and peer support. For most women who perceived themselves as the primary caregiver in the family there was a negative impact on their ability to cope fully with CR programme attendance. On the other hand, encouraging support from family and peers positively improved their coping mechanism for attending the CR programme, leading to improved compliance. CONCLUSION: Women with ACS consider that support from their family plays a vital role as a coping mechanism in their attendance at a CR programme. Healthcare providers should teach the importance of social support among women after discharge to help them cope with CR programme attendance.

Influence of vanillic acid immobilization in Nafion membranes on intramembrane diffusion and structural properties.

Pulsed field gradient (PFG) NMR in combination with quasielastic neutron scattering (QENS) was used to investigate self-diffusion of water and acetone in Nafion membranes with and without immobilized vanillic acid (VA). Complementary characterization of these membranes was performed by small angle X-ray scattering (SAXS) and NMR relaxometry. This study was motivated by the recent data showing that an organic acid, such as VA, in Nafion can preserve its catalytic activity in the presence of water even at high intra-polymer water concentrations corresponding up to 100% ambient relative humidity. However, there is currently no clear understanding of how immobilized organic acid molecules influence the microscopic transport properties and related structural properties of Nafion. Microscopic diffusion data measured by PFG NMR and QENS are compared for Nafion with and without VA. For displacements smaller than the micrometer-sized domains previously reported for Nafion, the VA addition was not observed to lead to any significant changes in the water and/or acetone self-diffusivity measured by each technique inside Nafion. However, the reported PFG NMR data present evidence of a different influence of acetone concentration in the membranes with and without VA on the water permeance of the interfaces between neighboring micrometer-sized domains. The reported diffusion data are correlated with the results of SAXS structural characterization and NMR relaxation data for water and acetone.

Motion characteristics of subclinical tremors in Parkinson's disease and normal subjects.

The characteristics of the Parkinson's disease tremor reported previously are not applicable to the full spectrum of severity. The characteristics of high- and low-amplitude tremors differ in signal regularity and frequency dispersion, a phenomenon that indicates characterisation should be studied separately based on the severity. The subclinical tremor of Parkinson's disease is close to physiological tremor in terms of amplitude and frequency, and their distinctive features are still undetermined. We aimed to determine joint motion characteristics that are unique to subclinical Parkinson's disease tremors. The tremors were characterised by four hand-arm motions based on displacement and peak frequencies. The rest and postural tremors of 63 patients with Parkinson's disease and 62 normal subjects were measured with inertial sensors. The baseline was established from normal tremors, and the joint motions were compared within and between the two subject groups. Displacement analysis showed that pronation-supination and wrist abduction-adduction are the most and least predominant tremor motions for both Parkinson's disease and normal tremors, respectively. However, the subclinical Parkinson's disease tremor has significant greater amplitude and peak frequency in specific predominant motions compared with the normal tremor. The flexion-extension of normal postural tremor increases in frequency from the proximal to distal segment, a phenomenon that is explainable by mechanical oscillation. This characteristic is also observed in patients with Parkinson's disease but with amplification in wrist and elbow joints. The contributed distinctive characteristics of subclinical tremors provide clues on the physiological manifestation that is a result of the neuromuscular mechanism of Parkinson's disease.

Study of Antibacterial and Anticancer Properties of bioAgNPs Synthesized Using Streptomyces sp. PBD-311B and the Application of bioAgNP-CNC/Alg as an Antibacterial Hydrogel Film against P. aeruginosa USM-AR2 and MRSA.

Here, we report the extracellular biosynthesis of silver nanoparticles (AgNPs) and determination of their antibacterial and anticancer properties. We also explore the efficacy of bioAgNPs incorporated in cellulose nanocrystals (CNCs) and alginate (Alg) for the formation of an antibacterial hydrogel film. Streptomyces sp. PBD-311B was used for the biosynthesis of AgNPs. The synthesized bioAgNPs were characterized using UV-Vis spectroscopy, TEM, XRD, and FTIR analysis. Then, the bioAgNPs' antibacterial and anticancer properties were determined using TEMA and cytotoxicity analysis. To form the antibacterial hydrogel film, bioAgNPs were mixed with a CNC and Alg solution and further characterized using FTIR analysis and a disc diffusion test. The average size of the synthesized bioAgNPs is around 69 ± 2 nm with a spherical shape. XRD analysis confirmed the formation of silver nanocrystals. FTIR analysis showed the presence of protein capping at the bioAgNP surface and could be attributed to the extracellular protein binding to bioAgNPs. The MIC value of bioAgNPs against P. aeruginosa USM-AR2 and MRSA was 6.25 mg/mL and 3.13 mg/mL, respectively. In addition, the bioAgNPs displayed cytotoxicity effects against cancer cells (DBTRG-0.5MG and MCF-7) and showed minimal effects against normal cells (SVG-p12 and MCF-10A), conferring selective toxicity. Interestingly, the bioAgNPs still exhibited inhibition activity when incorporated into CNC/Alg, which implies that the hydrogel film has antibacterial properties. It was also found that bioAgNP-CNC/Alg displayed a minimal or slow release of bioAgNPs owing to the intermolecular interaction and the hydrogel's properties. Overall, bioAgNP-CNC/Alg is a promising antibacterial hydrogel film that showed inhibition against the pathogenic bacteria P. aeruginosa and MRSA and its application can be further evaluated for the inhibition of cancer cells. It showed benefits for surgical resection of a tumor to avoid post-operative wound infection and tumor recurrence at the surgical site.

A life-threatening condition - ruptured ectopic pregnancy with negative urine pregnancy test: A case report.

Ectopic pregnancy is an extra-uterine pregnancy and is a potentially life-threatening condition that can lead to death from intra-peritoneal hemorrhage. This case reports a rare occurrence of ruptured tubal pregnancy in which the patient presented early with abdominal pain and a negative urine pregnancy test but subsequently presented again with evidence of intra-peritoneal hemorrhage. A negative urine pregnancy test is often used to rule out pregnancy, but it is not 100% sensitive. Complete assessment is critical in this important diagnosis in order to plan for the appropriate emergency management.

Production of lipopeptide biosurfactant in batch and fed-batch Streptomyces sp. PBD-410L cultures growing on palm oil.

The present study focused on lipopeptide biosurfactant production by Streptomyces sp. PBD-410L in batch and fed-batch fermentation in a 3-L stirred-tank reactor (STR) using palm oil as a sole carbon source. In batch cultivation, the impact of bioprocessing parameters, namely aeration rate and agitation speed, was studied to improve biomass growth and lipopeptide biosurfactant production. The maximum oil spreading technique (OST) result (45 mm) which corresponds to 3.74 g/L of biosurfactant produced, was attained when the culture was agitated at 200 rpm and aeration rate of 0.5 vvm. The best aeration rate and agitation speed obtained from the batch cultivation was adopted in the fed-batch cultivation using DO-stat feeding strategy to further improve the lipopeptide biosurfactant production. The lipopeptide biosurfactant production was enhanced from 3.74 to 5.32 g/L via fed-batch fermentation mode at an initial feed rate of 0.6 mL/h compared to that in batch cultivation. This is the first report on the employment of fed-batch cultivation on the production of biosurfactant by genus Streptomyces.

Transition between Different Diffusion Regimes and Its Relationship with Structural Properties in Nafion by High Field Diffusion NMR in Combination with Small-Angle X-ray and Neutron Scattering.

Pulsed field gradient (PFG) NMR at high field was utilized to directly observe a transition between two different diffusion regimes in a Nafion 117 membrane loaded with water and acetone. Although water self-diffusivity at small water loadings was observed to be diffusion time-independent in the limit of small and large diffusion times, it showed a significant decrease with increasing diffusion time at intermediate times corresponding to root mean square displacements on the order of several microns. Under our experimental conditions, no self-diffusivity dependence on diffusion time was found for water at large water loadings and for acetone at all studied acetone loadings. The diffusion time-dependent self-diffusivity at small water concentration is explained by the existence of finite domains of interconnected water channels with sizes in the range of several microns that form in Nafion in the presence of acetone. The domain sizes and permeance of transport barriers separating adjacent domains are estimated based on the measured PFG NMR data. At large water concentrations, the water channels form a fully interconnected network, resulting in time-independent self-diffusivity. The absence of such a percolation-like transition with increasing molecular concentration for acetone is attributed to a difference in the regions available for water and acetone diffusion in Nafion. The diffusion data are correlated with and supported by structural data obtained using small-angle X-ray and neutron scattering techniques. These techniques reveal distinct water channels with radial dimensions in the nanometer range increasing upon water addition, while acetone appears to be in an interfacial perfluoroether region, reducing the size of the radial channel dimension.

Molecular origins of bulk viscosity in liquid water.

The rapid equilibrium fluctuations of water molecules are intimately connected to the rheological response; molecular motions resetting the local structure and stresses seen as flow and volume changes. In the case of water or hydrogen bonding liquids generally, the relationship is a non-trivial consideration due to strong directional interactions complicating theoretical models and necessitating clear observation of the timescale and nautre of the associated equilibrium motions. Recent work has illustrated a coincidence of timescales for short range sub-picosecond motions and the implied timescale for the shear viscosity response in liquid water. Here, neutron and light scattering methods are used to experimentally illustrate the timescale of bulk viscosity and provide a description of the associated molecular relaxation. Brillouin scattering has been used to establish the timescale of bulk viscosity; and borrowing the Maxwell approach, the ratio of the bulk viscosity, ζ, to the bulk modulus, K, yields a relaxation time, τB, which emerges on the order of 1-2 ps in the 280 K to 303 K temperature range. Inelastic neutron scattering is subsequently used to describe the motions of water and heavy water at the molecular scale, providing both coherent and incoherent scattering data. A rotational (alternatively described as localized) motion of water protons on the 1-2 ps timescale is apparent in the incoherent scattering spectra of water, while the coherent spectra from D2O on the length scale of the first sharp diffraction peak, describing the microscopic density fluctuations of water, confirms the relaxation of water structure at a comparable timescale of 1-2 ps. The coincidence of these three timescales provides a mechanistic description of the bulk viscous response, with the local structure resetting due to rotational/localized motions on the order of 1-2 ps, approximately three times slower than the relaxations associated with shear viscosity. In this way we show that the shear viscous response is most closely associated with changes in water network connectivity, while the bulk viscous response is associated with local density fluctuations.

Review: Contemporary biological therapies for cardiovascular diseases.

Cardiovascular diseases are top cause of mortality in the world. Current interventional therapy and pharmacotherapy may alleviate symptoms or slow disease progression but are unable to cure or treat them. Molecular and pathophysiological advances have paved the way for contemporary biological therapies to be tested and standardized for the treatment of these diseases. Stem cells therapy and gene therapy has shown promise in the treatment of CVDs. Various types of stem cells used in cardiac conditions like myocardial infarction with the aim of regenerating the damaged myocardium have had variable success rates in clinical and preclinical trials. Improvements in methods and routes of cell delivery have improved clinical outcomes. Gene therapy employs therapeutic genes to treat diseases. Advances in vectors have improved transfection efficiencies and transgene expression and enhanced role in Heart failure, ischemic disease as well as arrhythmias. Clinical trials have shown improved cardiac function upon treatment with genes which promote angiogenesis. The current review looks at the role of these biological therapies in cardiovascular diseases.

Colorimetric Analysis of Glucose Oxidase-Magnetic Cellulose Nanocrystals (CNCs) for Glucose Detection.

Glucose oxidase (EC 1.1.3.4) sensors that have been developed and widely used for glucose monitoring have generally relied on electrochemical principle. In this study, the potential use of colorimetric method for glucose detection utilizing glucose oxidase-magnetic cellulose nanocrystals (CNCs) is explored. Magnetic cellulose nanocrystals (magnetic CNCs) were fabricated using iron oxide nanoparticles (IONPs) and cellulose nanocrystals (CNCs) via electrostatic self-assembly technique. Glucose oxidase was successfully immobilized on magnetic CNCs using carbodiimide-coupling reaction. About 33% of GOx was successfully attached on magnetic CNCs, and the affinity of GOx-magnetic CNCs to glucose molecules was slightly higher than free enzymes. Furthermore, immobilization does not affect the specificity of GOx-magnetic CNCs towards glucose and can detect glucose from 0.25 mM to 2.5 mM. Apart from that, GOx-magnetic CNCs stored at 4 °C for 4 weeks retained 70% of its initial activity and can be recycled for at least ten consecutive cycles.