A Study of Metal@Graphene Core–Shell Spherical Nano-Geometry to Enhance the SPR Tunability: Influence of Graphene Monolayer Shell Thickness

Graphene, new generation advance material of two dimensional hexagonal lattice having extraordinary optical signatures, is used as coating material to enhance the surface plasmon resonance (SPR) effect of core@shell metal nanospheres. In a core@shell nanosphere, we have chosen metal as a core and graphene monolayer (GML) as a shell. We have analysed optical signature of coated and non-coated nanospheres in terms of extinction efficiency (Q _ext) and tunabilty of surface plasmon resonances using electrostatic model, where particle size is much smaller than the wavelength of incident light. We analysed this model over different metals (silver, gold and aluminium) core, coated with different thickness of GML (d?=?0.1 to 0.5 nm). These core@shell nanospheres are embedded in refractive index media of air (n _em?=?1), SiO₂ (n _em?=?1.47) and TiO₂ (n _em?=?2.79). The Q _ext has been calculated by varying both the core radii as well as the GML shell thickness. Graphene-coated metal nanosphere exhibits SPRs that have wide range tunability from 300 to 1500 nm. In the presenting work, we also analysed that extinction efficiency for metal@GML is higher in TiO₂ than others. The optimum value of GML shell thickness is 0.4 nm for TiO₂, the magnitude of extinction efficiency is maximum for the optimum thickness. The tunability of these plasmonic resonances is highly dependent on the core@shell material, thickness of Graphene shell and surrounding environment while non-coated metal nano-spheres do not show appropriate SPR tunability.     

A possible role of poly-3-hydroxybuiyric acid in antibiotic production in<Emphasis Type="Italic">Streptomyces</Emphasis>

The occurrence of poly-3-hydroxybutyric acid (PHB) in 12 different strains of the genus Streptomyces was investigated. Gas chromatographic estimation indicated that all the strains produced PHB and the range of maximum PHB accumulation was between 1.5 and 11.8% dry cell weight. PHB was isolated from Streptomyces coelicolor A3(2) M145 and characterized using Fourier transform-infrared (FT-IR) spectroscopy. The correlation between PHB utilization and antibiotic production in S. coelicolor A3(2) M145, was studied; results indicated a possible role of PHB as a carbon reserve material used for antibiotic production.     

Calculations of intracapillary oxygen tension distributions in muscle

Characterizing the resistances to O(2) transport from the erythrocyte to the mitochondrion is important to understanding potential transport limitations. A mathematical model is developed to accurately determine the effects of erythrocyte spacing (hematocrit), velocity, and capillary radius on the mass transfer coefficient. Parameters of the hamster cheek pouch retractor muscle are used in the calculations, since significant amounts of experimental physiological data and mathematical modeling are available for this muscle. Capillary hematocrit was found to have a large effect on the PO(2) distribution and the intracapillary mass transfer coefficient per unit capillary area, k(cap), increased by a factor of 3.7 from the lowest (H=0.25) to the highest (H=0.55) capillary hematocrits considered. Erythrocyte velocity had a relatively minor effect, with only a 2.7% increase in the mass transfer coefficient as the velocity was increased from 5 to 25 times the observed velocity in resting muscle. The capillary radius is varied by up to two standard deviations of the experimental measurements, resulting in variations in k(cap) that are <15% at the reference case. The magnitude of these changes increases with hematocrit. An equation to approximate the dependence of the mass transfer coefficient on hematocrit is developed for use in simulations of O(2) transport from a capillary network.     

The Streptococcus pyogenes orphan protein tyrosine phosphatase,SP‐PTP,possesses dual specificity and essential virulence regulatory functions

Group A Streptococcus (GAS) is a human pathogen that causes high morbidity and mortality. GAS lacks a gene encoding tyrosine kinase but contains one encoding tyrosine phosphatase (SP‐PTP). Thus, GAS is thought to lack tyrosine phosphorylation, and the physiological significance of SP‐PTP is, therefore, questionable. Here, we demonstrate that SP‐PTP possesses dual phosphatase specificity for Tyr‐ and Ser/Thr‐phosphorylated GAS proteins, such as Ser/Thr kinase (SP‐STK) and the SP‐STK‐phosphorylated CovR and WalR proteins. Phenotypic analysis of GAS mutants lacking SP‐PTP revealed that the phosphatase activity per se positively regulates growth, cell division and the ability to adhere to and invade host cells. Furthermore, A549 human lung cells infected with GAS mutants lacking SP‐PTP displayed increased Ser‐/Thr‐/Tyr‐phosphorylation. SP‐PTP also differentially regulates the expression of ～50% of the total GAS genes, including several virulence genes potentially through the two‐component regulators, CovR, WalR and PTS/HPr regulation of Mga. Although these mutants exhibit attenuated virulence, a GAS mutant overexpressing SP‐PTP is hypervirulent. Our study provides the first definitive evidence for the presence and importance of Tyr‐phosphorylation in GAS and the relevance of SP‐PTP as an important therapeutic target.     

Differential Metabolic Reprogramming by Zika Virus Promotes Cell Death in Human versus Mosquito Cells

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The Effects of Face Masks on the Doctor-Patient Relationship in Orthopaedics

BackgroundSince the onset of the COVID-19 pandemic, the widespread use of face masks has grown exponentially. There is limited data highlighting the patient perception of face mask use during this pandemic, specifically in orthopaedic clinics. The purpose of this study was to determine the patient’s perception of the implementation of face masks in the orthopaedic clinic during a period of mask mandates and if this change impacted the success of their interactions with physicians. The secondary aim includes measures of patient satisfaction such as the ability to understand conversation and communicate effectively with the physician.MethodsParticipants were recruited on the day of their appointment at our institution’s orthopaedic clinic and provided with instructions via email. The online, anonymous survey included the CARE questionnaire - a tool to examine patient satisfaction by assessing perception of empathy and was conducted using Qualtrics.ResultsDoes patient preference to have their physician wear a face mask impact the success of their interactions with physicians? Overall, the use of face masks by physicians did not negatively impact patient encounters. CARE scores for patients who preferred masks (37.2) were similar to those who preferred their physician did not wear a mask (37.5). Is patient satisfaction affected by the use of face masks in the orthopaedic clinic? Patients who preferred that their doctor wear a face mask stated that it had no negative impact on the effect of communication or conversation with the physician. Other factors such as how well the patients knew the physician and patient gender had a greater impact on the CARE score than masks did.ConclusionOur study determined that the preference of face masks by patients does not impact the success of their interactions with physicians using the CARE score. The findings of this study are valuable in informing orthopaedic physicians about patient attitudes towards mask use and could influence decision making for not only the COVID-19 pandemic, but also future infectious outbreaks that may arise. Level of Evidence: III     

Purification of a -hydantoinase using a laboratory-scale Streamline phenyl column as the initial step

A -hydantoinase from Thermus sp. was overexpressed in Escherichia coli and purified to homogeneity for subsequent crystallization. The purification was performed with hydrophobic interaction chromatography as the capture step followed by anion-exchange chromatography and gel permeation chromatography as intermediate purification and polishing steps, respectively. The hydrophobic interaction step was done in fluidized bed mode in a laboratory-scale Streamline column made from conventional laboratory equipment. The whole purification protocol could be finished within one day. The purified enzyme crystallizes. The crystals are suitable for X-ray protein structure analysis and diffract to at least 2.3 Å resolution. Complete data sets have been measured up to 2.6 Å resolution. The X-ray structure is currently being solved.