Impact of surface tension on the barrier performance of gowns and coveralls.

Background: Health care workers and laboratory workers who are routinely exposed to potentially life-threatening infectious diseases should wear protective clothing when anticipating contact with infectious materials. The most critical property of protective clothing is its ability to prevent liquids and viruses from passing through the garment. There are a number of potentially infectious liquids that workers may be exposed to during routine tasks.

Photomechanical response under physiological conditions of azobenzene-containing 4D-printed liquid crystal elastomer actuators.

Soft and mechanically responsive actuators hold the promise to revolutionize the design and manufacturing of devices in the areas of microfluidics, soft robotics and biomedical engineering. In many of these applications, the actuators need to operate in a wet environment that can strongly affect their performance. In this paper, we report on the photomechanical response in a biological buffer of azobenzene-containing liquid crystal elastomer (LCE)-based actuators, prepared by four-dimensional (4D) printing.

Systematic comparison of unilamellar vesicles reveals that archaeal core lipid membranes are more permeable than bacterial membranes.

One of the deepest branches in the tree of life separates the Archaea from the Bacteria. These prokaryotic groups have distinct cellular systems including fundamentally different phospholipid membrane bilayers. This dichotomy has been termed the lipid divide and possibly bestows different biophysical and biochemical characteristics on each cell type.

Evaluation of fluid leakage at the coverall and glove interface in single and double glove conditions.

Background: Fluid leakage through the glove-protective clothing interface is an area of concern for many health care personnel, including emergency medical service providers, who may wear coveralls to protect themselves from multiple types of hazards. There is currently no established standard test method to specifically evaluate the barrier performance of the glove-protective clothing interface region for any personal protective equipment ensemble.

Objective: This study quantifies the fluid leakage at the coverall and glove interface using single and double gloving.

A simulation study to assess fluid leakage through the glove-gown interface in isolation settings.

Background: Isolation gowns are recommended to protect healthcare personnel, patients, and visitors from transfer of microorganisms and body fluids in patient isolation situations. Standards provide limited information about barrier performance of isolation gowns for possible exposure scenarios. One of the most vulnerable areas of the personal protective equipment ensemble is considered the glove-gown interface.

Heterologous Protein Expression Favors the Formation of Protein Aggregates in Persister and Viable but Nonculturable Bacteria.

Environmental and intracellular stresses can perturb protein homeostasis and trigger the formation and accumulation of protein aggregates. It has been recently suggested that the level of protein aggregates accumulated in bacteria correlates with the frequency of persister and viable but nonculturable cells that transiently survive treatment with multiple antibiotics. However, these findings have often been obtained employing fluorescent reporter strains.

Barrier resistance of double layer isolation gowns.

Background: Isolation gowns are one of the crucial pieces of personal protective equipment (PPE) to prevent the migration of microorganisms and body fluids from patients to health care personnel and vice versa. Underperforming isolation gowns in terms of fluid resistance, could potentially put lives in danger. Wearing multiple layers of isolation gowns could theoretically increase the fluid penetration resistance.

Four-Dimensional Printed Liquid Crystalline Elastomer Actuators with Fast Photoinduced Mechanical Response toward Light-Driven Robotic Functions.

Remote light exposure of photoresponsive liquid crystalline polymers has drawn great attention over the last years as an attractive strategy to generate mechanical work with high spatial resolution. To tailor these materials into practical engineering devices, it is of key importance to gain control over their morphology and thus precisely program their mechanical response, which must also be fast and relevant in magnitude. In this communication, we report the four-dimensional (4D) printing of azobenzene-containing liquid crystalline elastomers (LCEs) that respond to light.

Effect of DMSO on the Mechanical and Structural Properties of Model and Biological Membranes.

Dimethyl sulfoxide (DMSO) is widely used in a number of biological and biotechnological applications, mainly because of its effects on the cell plasma membrane, but the molecular origins of this action are yet to be fully clarified. In this work, we used two- and three-component synthetic membranes (liposomes) and the plasma membrane of human erythrocytes to investigate the effect of DMSO when added to the membrane-solvating environment. Fourier transform infrared spectroscopy and thermal fluctuation spectroscopy revealed significant differences in the response of the two types of liposome systems to DMSO in terms of the bilayer thermotropic behavior, available free volume of the bilayer, its excess surface area, and bending elasticity.

Critical investigation of glove-gown interface barrier performance in simulated surgical settings.

The barrier properties of personal protective equipment are vital to healthcare personnel to protect themselves from possible infectious body fluids. Intraoperative exposure of healthcare personnel to body fluids can be substantial in both inpatient and outpatient settings. The glove-gown interface is known as one of the weakest points of the whole personal protective equipment system.

Synthesis and Characterization of a Novel Green Cationic Polyfluorene and Its Potential Use as a Fluorescent Membrane Probe.

In the present work, we have synthesized a novel green-emitter conjugated polyelectrolyte Copoly-{[9,9-bis(6'-,,-trimethylammonium)hexyl]-2,7-(fluorene)--4,7-(2-(phenyl) benzo[d] [1,2,3] triazole)} bromide (HTMA-PFBT) by microwave-assisted Suzuki coupling reaction. Its fluorescent properties have been studied in aqueous media and in presence of model membranes of different composition, in order to explore its ability to be used as a green fluorescent membrane probe. The polyelectrolyte was bound with high affinity to the membrane surface, where it exhibited high fluorescence efficiency and stability.

Novel Test Method for the Evaluation of Fluid Leakage at the Glove-Gown Interface and Investigation of Test Parameters.

Background: Exposure to patients' blood/body fluids could be life-affecting, when providing care to patients with infectious diseases. Although the glove-gown interface is considered one of the weakest points of the protective ensemble system, there is a lack of research, and existing standards do not provide much guidance on strategies to minimize gaps between the gowns and gloves. Currently, there is no known standard test method to evaluate fluid leakage or assess performance improvements with new gowns/gloves.

Fluorescent Biosensor for Phosphate Determination Based on Immobilized Polyfluorene-Liposomal Nanoparticles Coupled with Alkaline Phosphatase.

This work describes the development of a novel fluorescent biosensor based on the inhibition of alkaline phosphatase (ALP). The biosensor is composed of the enzyme ALP and the conjugated cationic polyfluorene HTMA-PFP. The working principle of the biosensor is based on the fluorescence quenching of this polyelectrolyte by p-nitrophenol (PNP), a product of the hydrolysis reaction of p-nitrophenyl phosphate (PNPP) catalyzed by ALP.

Selective recognition and imaging of bacterial model membranes over mammalian ones by using cationic conjugated polyelectrolytes.

The development of new tools for the detection and fluorescence imaging of bacteria is of great interest in clinical diagnosis and food and environmental safety. In this work, we have explored the ability of two cationic fluorene-based conjugated polyelectrolytes, HTMA-PFP and HTMA-PFNT, emitting in the blue and red spectral regions respectively, to selectively label bacterial over mammalian cells. With this end in view, vesicles with lipid compositions mimicking those of bacterial or mammalian membranes were used as model membranes to explore the interaction of the polyelectrolytes with both systems in samples containing either a single type of vesicle or a mixture of both.

Enhanced Carbon Dioxide Capture from Landfill Gas Using Bifunctionalized Benzimidazole-Linked Polymers.

Tuning the binding affinity of small gases and their selective uptake by porous adsorbents are vital for effective CO2 removal from gas mixtures for environmental protection and fuel upgrading. In this study, an amine-functionalized benzimidazole-linked polymer (BILP-6-NH2) was synthesized by a combination of pre- and postsynthetic modification techniques in two steps. Presynthetic incorporation of nitro groups resulted in stoichiometric functionalization (1 nitro/phenyl) in addition to noninvasive functionalization, where more than 80% of the surface area maintained compared to BILP-6.

New Red-Emitting Conjugated Polyelectrolyte: Stabilization by Interaction with Biomolecules and Potential Use as Drug Carriers and Bioimaging Probes.

The design and development of fluorescent conjugated polyelectrolytes (CPEs) emitting in the red region of the visible spectrum is at present of great interest for bioimaging studies. However, despite the wide variety of CPEs available, stable bright red-emitters remain scarce due to their low solubility and instability in aqueous media, consequently limiting their applications. In this work, we have synthesized and characterized a new red-emitting cationic conjugated polyelectrolyte copoly-{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]-2,7-(fluorene)-alt-1,4-(naphtho[2,3c]-1,2,5-thiadiazole)} bromide (HTMA-PFNT), based on the incorporation of naphtha[2,3c][1,2,5] thiadiazole on fluorene backbone to increase the bathochromic emission, extending the conjugation length in the polymer backbone.

Selective Interaction of a Cationic Polyfluorene with Model Lipid Membranes: Anionic Zwitterionic Lipids.

This paper explores the interaction mechanism between the conjugated polyelectrolyte {[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene}bromide (HTMA-PFP) and model lipid membranes. The study was carried out using different biophysical techniques, mainly fluorescence spectroscopy and microscopy. Results show that despite the preferential interaction of HTMA-PFP with anionic lipids, HTMA-PFP shows affinity for zwitterionic lipids; although the interaction mechanism is different as well as HTMA-PFP's final membrane location.

Use of the conjugated polyelectrolyte poly{[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene} bromide (HTMA-PFP) as a fluorescent membrane marker.

The present work explores the potential use of the conjugated cationic polyfluorene {[9,9-bis(6'-N,N,N-trimethylammonium)hexyl]fluorene-phenylene} bromide (HTMA-PFP) as a fluorescent membrane marker. To this end, the interaction of the polyelectrolyte with anionic model membranes has been investigated using different biophysical approaches. High affinity interaction was confirmed through alterations in the fluorescence spectrum of HTMA-PFP and by Förster resonance energy transfer (FRET) analysis.

Stabilization of neutral polyfluorene in aqueous solution through their interaction with phospholipids and sol-gel encapsulation.

Interaction between poly[9,9-bis(6'-bromohexyl)-2,7-fluorene-co-alt-1,4-phenylene] (PFPBr2), a neutral conjugated polyfluorene which is completely insoluble in water, and zwitterionic phospholipids has been investigated in order to generate new fluorescent structures which are stable in aqueous media as a means of extending the biological applications of these kinds of polymers. Two types of differently shaped and composed fluorescent structures were identified and then isolated and characterized separately using different biophysical techniques. The first structure type, corresponding to liposomal complexes, showed a fluorescence band centered around 405 nm and maximum absorption at 345 nm, while the second, corresponding to polymer-phospholipid aggregates of variable sizes with lower lipid content, absorbed at longer wavelengths and displayed a well resolved fluorescence spectrum with a maximum centered at 424 nm.

A 2D mesoporous imine-linked covalent organic framework for high pressure gas storage applications.

Hole-some mixture: A 2D mesoporous covalent organic framework (see figure) featuring expanded pyrene cores and linked by imine linkages has a high surface area (SA(BET) = 2723 m(2)  g(-1)) and exhibits significant gas storage capacities under high pressure, which make this class of material very promising for gas storage applications.

Cyclooxygenase-2 expression in astrocytes and microglia in human oligodendroglioma and astrocytoma.

Cyclooxygenases (cox) are potent mediators of inflammation and two cox-isoenzymes, cox-1, cox-2, are described to date. Cox-2 is cytokine-inducible in inflammatory cells and enhanced cox-2 expression has been attributed a key role in the development of edema and immunomodulation in pathologically altered brain tissues. In normal cerebral cortex cox-2 is present only in neurons, but not in the glial or vascular endothelial cells.

Immunohistochemical detection of p53 protein in basal cell skin cancer after microwave-assisted antigen retrieval.

p53 is the most frequently altered tumor-suppressor gene in skin cancer. In normal tissues the p53 protein (wild type) has a very short half-life and it is not detectable immunohistochemically. In contrast, the mutant p53 protein has an extended half-life in tumor cells and can be detected by immunohistochemical methods.

Using microwave irradiation in Marchi's method for demonstrating degenerated myelin.

Conventional methods for histological preparation of degenerated myelin are time-consuming and difficult. The purpose of our study was to shorten the time required for the procedure and to obtain better quality results for light microscopic demonstration of degenerated myelin in the central and peripheral nervous systems by using microwave irradiation. Rat brain and sciatic nerve were used for the study.

Microwave-assisted antigen retrieval and incubation with cox-2 antibody of archival paraffin-embedded human oligodendroglioma and astrocytomas.

Immunohistochemistry is an important tool that is often used for the diagnosis of pathologies; however, the length of time required to process the tissue is relatively long. Furthermore, the quality and sensitivity of immunohistochemical staining is affected by formalin fixation which results in variable loss of antigenicity, known as masking effect. Here we assess the effect of microwave irradiation on the incubation time required to obtain high quality immunohistochemical staining for cox-2 using archival formalin-fixed, paraffin-embedded human oligodendrogliomas and astrocytomas.

A simple and rapid microwave-assisted hematoxylin and eosin staining method using 1,1,1 trichloroethane as a dewaxing and a clearing agent.

The use and practicability of microwave-assisted staining procedures in routine histopathology has been well established for more than 17 years. In the study reported here, we aimed to examine an alternative approach that would shorten the duration of dewaxing and clearing steps of hematoxylin and eosin (H & E) staining of paraffin sections by using a microwave oven. Although xylene is one of the most popular dewaxing and clearing agents, its flammability restricts its use in a microwave oven; thus we preferred 1,1,1 trichloroethane, which is not flammable, as the dewaxing and clearing agent in the present study.