Revisiting the Interaction of Melittin with Phospholipid Bilayers: The Effects of Concentration and Ionic Strength.

Melittin is an anti-microbial peptide (AMP) and one of the most studied membrane-disrupting peptides. There is, however, a lack of accurate measurements of the concentration-dependent kinetics and affinity of binding of melittin to phospholipid membranes. In this study, we used surface plasmon resonance spectroscopy to determine the concentration-dependent effect on the binding of melittin to 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) bilayers in vesicles. Three concentration ranges were considered, and when combined, covered two orders of magnitudes (0.04 µM to 8 µM), corresponding to concentrations relevant to the membrane-disrupting and anti-microbial activities of melittin. Binding kinetics data were analysed using a 1:1 Langmuir-binding model and a two-state reaction model. Using in-depth quantitative analysis, we characterised the effect of peptide concentration, the addition of NaCl at physiological ionic strength and the choice of kinetic binding model on the reliability of the calculated kinetics and affinity of binding parameters. The apparent binding affinity of melittin for POPC bilayers was observed to decrease with increasing peptide/lipid (P/L) ratio, primarily due to the marked decrease in the association rate. At all concentration ranges, the two-state reaction model provided a better fit to the data and, thus, a more reliable estimate of binding affinity. Addition of NaCl significantly reduced the signal response during the association phase; however, no substantial effect on the binding affinity of melittin to the POPC bilayers was observed. These findings based on POPC bilayers could have important implications for our understanding of the mechanism of action of melittin on more complex model cell membranes of higher physiological relevance

3-Methyl-5-(3-phenoxy­phen­yl)cyclo­hex-2-enone

In the title mol­ecule, C19H18O2, the cyclo­hexene ring adopts an envelope conformation, with all substituents equatorial. The dihedral angle between the benzene and phenyl rings is 83.75 (16)°. No classical hydrogen bonds are found in the crystal structure

Evaluating the Feasibility and Impact of a Well-being Retreat for Physicians and Advanced Practice Providers

Introduction: Work stress experienced by physicians and advanced practice providers (APPs) can have a detrimental psychological and physical impact. Targeted interventions that focus on self-awareness, peer connection, and intentional self-care may reduce stress and improve well-being and professional fulfillment. Methods: This is a summative program evaluation of a two-day well-being retreat for physicians and APPs employed at a healthcare system headquartered in Florida. Led by mental health professionals in May 2022, this retreat combined facilitator-led workshops and experiential practice activities with opportunities for peer connection and designated time with family members. The retreat objectives were to facilitate social support, improve knowledge in areas of self-care, and build reflection skills that lead to intentional changes in well-being. Data collection occurred immediately before and after the intervention in May 2022. Wilcoxon Signed Ranks Tests were conducted to examine pre-post differences in the outcomes of self-reflection and insight, mindful self-care, anxiety, perceived stress, and professional fulfillment. Post-program feedback was collected, synthesized, and described. Results: Twenty-one clinicians attended the retreat, and a self-selected sample of twelve attendees participated in the evaluation portion of the project. Perceived stress significantly decreased (19.00 vs. 15.92; p = 0.01), and professional fulfillment significantly improved (15.50 vs. 17.50; p = 0.04) following the retreat. Participants reported the following benefits of the retreat: a reminder to focus on self-care, motivation for healthy behavior change, and an opportunity to self-reflect. Conclusion: Findings suggest that the retreat intervention met its objectives, and there is preliminary evidence that it may be a feasible approach to improve well-being and reduce stress in physicians and APPs. While significant changes in the practice environment are necessary to address the causes and consequences of work stress, individual-level programs remain important and relevant to the protection of well-being. This project builds upon the literature about interventions with diverse modalities

3-Methyl-5-(4-methyl­phen­yl)cyclo­hex-2-enone

In the title mol­ecule, C14H16O, the cyclo­hexene ring adopts an envelope conformation, with all substituents equatorial. Mol­ecules are linked by C—H⋯O hydrogen bonds. A C—H⋯π inter­action involving the benzene ring is also found in the crystal structure. The H atoms of both methyl groups are disordered equally over two positions

A high gain pifa at 2.45 GHz and 5.8 GHz using wireless power transfer techniques for pacemaker application

The design of a high gain Planar Inverted F Antenna (PIFA) with two different frequencies for medical pacemaker is presented. Two PIFA designs have been optimized to be operated at ISM band of 2.45 GHz and 5.8 GHz respectively, under tolerable reflection coefficient of less than -10dB. Both of the proposed antennas are developed from copper plate with a simple structure of rectangular patch. All design and simulation has been carried out using Computer Simulation Technology (CST) Microwave Studio Suite. The simulated and measured results of the fabricated antenna on reflection coefficient, bandwidth radiation pattern, and gain are presented to validate the usefulness of the presented design. The 2D Anechoic Chamber and Agilent Technologies Network Analyzer have been used for the measurement. Both 2.45 GHz and 5.8 GHz antennas have successfully manage to achieve high gain of 6dB and 8.2dB respectively with a directional beam pattern. The presented ISM PIFAs could be potential for point-to-point communication using wireless power transfer technique for medical pacemaker application

5-(4-Chloro­phen­yl)-1-methyl-3-oxocyclo­hexa­necarbonitrile

In the title mol­ecule, C14H14ClNO, the cyclo­hexane ring adopts a chair conformation. The cyano group and the methyl group have axial and equatorial orientations, respectively. The benzene ring has an equatorial orientation. A C—H⋯π inter­action involving the benzene ring is found in the crystal structure

A Reconfigurable WiMAX Antenna for Directional and Broadside Application

A novel reconfigurable compact patch array antenna for directional and broadside application is proposed. The presented antenna has successfully been able to function for directional beam at 320° or 35° and divisive broadside beam at 43° and 330°. This is realized in the unique form of aperture coupled spiral feeding technique and positioning of the radiating elements at 0°, 90,° and 180°. The switchable feature is effectively performed by the configuration of three PIN diodes. All PIN diodes are positioned at the specific location of the aperture coupled structure. It is discovered in simulation that the switches can be represented with a copper strip line or touchstone (TS) block . The proposed antenna design operates at 2.37 GHz to 2.41 GHz and has a maximum gain of 6.4 dB and efficiency of 85.97%. Such antenna produces a broadside HPBW with a wider bandwidth covering from −90° to 90° compared to the normal microstrip antenna which could only provide HPBW of −50° to 50°. Moreover, the proposed antenna has small physical dimension of 100 mm by 100 mm. The simulation and measurement results have successfully exhibited the idea of the presented antenna performance. Therefore, the antenna is sufficiently competent in the smart WiMAX antenna application

A Patternless Piezoelectric Energy Harvester for Ultra Low Frequency Applications

This paper presents a pattern less piezoelectric harvester for ultra low power energy applications. Usually patterned cantilevers are used as vibration energy harvester which results additional fabrication process. Hence, to reduce the process, a four layer cantilever configuration is used to design the harvester with Aluminum, Silicon and Zinc Oxide. The device dimension is settled to 12×10×≈0.5009 mm3 with ≈300 nm deposition thickness for each layer. The modeling and fabrication processes are demonstrated in detail. The induced voltage by the cantilever is obtained through the analytical and practical measurements. From the measurements, it is found that, the maximum induced voltage is 91.2 mV from practical measurement with voltage density of 1.517 mV/mm3. It is evident from the results that, this pattern less model can be useful for next generation vibration energy harvester with simpler technology

Statins do not directly inhibit the activity of major epigenetic modifying enzymes

The potential anticancer effects of statins—a widely used class of cholesterol loweringdrugs—has generated significant interest, as has the use of epigenetic modifying drugs such asHDAC and DNMT inhibitors. We set out to investigate the effect of statin drugs on epigeneticmodifications in multiple cell lines, including hepatocellular carcinoma, breast carcinoma, leukemicmacrophages, cervical adenocarcinoma, and insulin-secreting cells, as well as liver extracts fromstatin-treated C57B1/6J mice. Cells or cell extracts were treated with statins and with establishedepigenetic modulators, and HDAC, HAT, and DNMT activities were quantified. We also examinedhistone acetylation by immunoblotting. Statins altered neither HDAC nor HAT activity. Accordingly,acetylation of histones H3 and H4 was unchanged with statin treatment. However, statins tended toincrease DNMT activity. These results indicate that direct inhibition of the major classes of epigeneticmodifying enzymes, as previously reported elsewhere, is unlikely to contribute to any anticancereffects of statins. This study concerned global effects on epigenetic enzyme activities and histoneacetylation; whether statins influence epigenetic modifications in certain genomic regions, cannot beruled out and remains to be investigated