Experimental and Analytical Investigation of the Response of a Triboelectric Generator Under Different Operating Conditions

This article provides experimental and theoretical studies on the effect of operating conditions on the output response of triboelectric generators. The influence of specific parameters is examined in detail, including vibration frequency, impact separation distance, and the type of adhesive between the dielectric and the electrode for a single dielectric layer device operating in contact-separation mode, with Teflon and copper being the dielectric and electrode materials, respectively. A scotch-yoke mechanism is designed and fabricated in an effort to understand the effect of varying the operating conditions on the output voltage behavior. The voltage output is compared with an analytical capacitor model at drive frequencies ranging from 1 to 5 Hz and separation distances from 5 to 40 mm to evaluate the model's effectiveness in predicting generator output. The experimental results provide new insights into the behavior of triboelectric generators and how the type of adhesive between the dielectric material and the electrode affects the output signal.</p

Efficacy and safety of the new generation Watchman FLX device compared to the Watchman 2.5: a systematic review and meta-analysis.

The first-generation Watchman 2.5 (W 2.5) presented several limitations, such as challenges in implantation within complex left atrial appendage (LAA) anatomies, higher incidence of peri-device leak, device recapture, and device-related thrombus (DRT). The newer generation Watchman FLX (W-FLX) was introduced with a modified design aiming to overcome these limitations. The purpose of this meta-analysis is to conduct a comparative assessment of the safety and efficacy of the W-FLX and 2.5 devices in clinical practice. The meta-analysis was conducted according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA). Studies were located through a search strategy utilizing PubMed, Cochrane, Google scholar and MEDLINE from inception to March 2023, with a primary objective to compare the safety and efficacy of the W-FLX and W 2.5 devices. After applying the selection criteria, five studies were included in this analysis. The analysis included five studies comprising 54,727 patients. The W-FLX is associated with an increase in procedural success (OR 7.49 [95% CI 1.98-28.26, P = 0.02; = 0%]), and a significant reduction in mortality (OR 0.52 [95% CI 0.51-0.54, P<0.01; = 0%], major bleeding 0.57 [95% CI 0.51-0.64, P<0.01; = 0%]), device embolism (OR 0.35 [95% CI 0.18-0.70, P = 0.02; = 0%]), and pericardial effusion (OR 0.33 [95% CI 0.26-0.41, P<0.01; = 0%]). The rates of DRT and stroke were similar between the two groups. Compared to the W 2.5, the W-FLX was associated with a higher procedural success rate and significantly reduced adverse outcomes including mortality, major bleeding, device embolization, and pericardial effusion. [Abstract copyright: AJCD Copyright © 2023.

Tuning triboelectric and energy harvesting properties of dielectric elastomers <i>via</i> dynamic ionic crosslinks

The bromination of poly(isobutylene-co-isoprene) rubber introduces a small amount of bromide groups (1–2 mol%) to the elastomer backbone and creates new opportunities for functionalisation, as compared to other saturated and diene elastomers. In this work, three types of nucleophile reagents: namely pyridine, triphenylphosphine and imidazoles bearing four types of side groups of methyl, ethyl, hydroxyl or vinyl group were introduced to brominated poly(isobutylene-co-isoprene) rubber (BIIR) through nucleophile substitution with the bromine via solid-state rubber compounding and curing processes. The resulted ionic aggregates act as physical crosslinks and their size and density directly affected the mechanical reinforcement, self-healing and dynamic mechanical properties of the elastomers. The smaller and polar imidazolyl/bromine pairs led to the highest reinforcement beyond even the sulfur-cured BIIR counterparts. The 1-ethyl imidazole (EIm) modified BIIR showed the highest tensile strength of 17.01 ± 1.89 MPa and elongation at break of 1402 ± 69% with self-healing efficiency of 63.7%, after being treated at 140 °C for 30 min. In addition, the inclusion of the ionic clusters enhanced the relative permittivity of the elastomer, thereby enhancing the energy conversion efficiencies. The nucleophile substitution reaction via conventional solid-state rubber compounding processes provides a facile crosslinking and reinforcement strategy for halogen-containing polymers. In addition, the dynamic ionic crosslinking networks spontaneously benefit electromechanical and self-healing properties of the dielectric elastomers

Tuning triboelectric and energy harvesting properties of dielectric elastomers via dynamic ionic crosslinks

The bromination of poly(isobutylene-co-isoprene) rubber introduces a small amount of bromide groups (1–2 mol%) to the elastomer backbone and creates new opportunities for functionalisation, as compared to other saturated and diene elastomers. In this work, three types of nucleophile reagents: namely pyridine, triphenylphosphine and imidazoles bearing four types of side groups of methyl, ethyl, hydroxyl or vinyl group were introduced to brominated poly(isobutylene-co-isoprene) rubber (BIIR) through nucleophile substitution with the bromine via solid-state rubber compounding and curing processes. The resulted ionic aggregates act as physical crosslinks and their size and density directly affected the mechanical reinforcement, self-healing and dynamic mechanical properties of the elastomers. The smaller and polar imidazolyl/bromine pairs led to the highest reinforcement beyond even the sulfur-cured BIIR counterparts. The 1-ethyl imidazole (EIm) modified BIIR showed the highest tensile strength of 17.01 ± 1.89 MPa and elongation at break of 1402 ± 69% with self-healing efficiency of 63.7%, after being treated at 140 °C for 30 min. In addition, the inclusion of the ionic clusters enhanced the relative permittivity of the elastomer, thereby enhancing the energy conversion efficiencies. The nucleophile substitution reaction via conventional solid-state rubber compounding processes provides a facile crosslinking and reinforcement strategy for halogen-containing polymers. In addition, the dynamic ionic crosslinking networks spontaneously benefit electromechanical and self-healing properties of the dielectric elastomers

Performance Investigation of a Proposed Flipped npn Microstructure Silicon Solar Cell Using TCAD Simulation

This work aims at inspecting the device operation and performance of a novel flipped npn microstructure solar cell based on low-cost heavily doped silicon wafers. The flipped structure was designed to eliminate the shadowing effect as applied in the conventional silicon-based interdigitated back-contact cell (IBC). Due to the disappearance of the shadowing impact, the optical performance and short-circuit current density of the structure have been improved. Accordingly, the cell power conversion efficiency (PCE) has been improved in comparison to the conventional npn solar cell microstructure. A detailed analysis of the flipped npn structure was carried out in which we performed TCAD simulations for the electrical and optical performance of the flipped cell. Additionally, a comparison between the presented flipped microstructure and the conventional npn solar cell was accomplished. The PCE of the conventional npn structure was found to be 14.5%, while it was about 15% for the flipped structure when using the same cell physical parameters. Furthermore, the surface recombination velocity and base bulk lifetime, which are the most important recombination parameters, were studied to investigate their influence on the flipped microstructure performance. An efficiency of up to 16% could be reached when some design parameters were properly fine-tuned. Moreover, the impact of the different physical models on the performance of the proposed cell was studied, and it was revealed that band gap narrowing effect was the most significant factor limiting the open-circuit voltage. All the simulations accomplished in this analysis were carried out using the SILVACO TCAD process and device simulators

Chrysosporazines F–M: P-glycoprotein inhibitory phenylpropanoid piperazines from an Australian marine fish derived fungus, Chrysosporium sp. CMB-F294

Chemical analysis of the fungus sp. CMB-F294 isolated from the gastrointestinal tract of a market-purchased specimen of mullet yielded eight new alkaloids, belonging to a rare class of phenylpropanoid piperazines. Chrysosporazines F-M (-) occur as an equilibrium mixture of acetamide rotamers and feature unprecedented carbocyclic and heterocyclic scaffolds. Structures inclusive of absolute configuration were assigned by detailed spectroscopic analysis, supported by biosynthetic considerations. Structure-activity relationship studies determined that selected chrysosporazines were promising noncytotoxic inhibitors of the multidrug resistance efflux pump P-glycoprotein (P-gp), capable of reversing doxorubicin resistance in P-gp-overexpressing human colon carcinoma cells (SW620 Ad300). Chrysosporazine F () was particularly noteworthy, with a 2.5 μM cotreatment inducing a doxorubicin gain in sensitivity (GS 14) > 2-fold that of the positive control verapamil (GS 6.1)

Impact of core stability exercises vs. interferential therapy on pelvic floor muscle strength in women with pelvic organ prolapse

OBJECTIVE: Pelvic organ prolapse (POP) is the descent of the pelvic organs into or through the vaginal walls. Females who have prolapse have symptoms that interfere with their daily lives, sexual function, and exercise. POP can have a negative effect on one’s sexuality and body image. This study attempted to assess the significance of core stability exercises vs. interferential therapy on the power of the pelvic floor muscles in females with prolapsed pelvic organs. PATIENTS AND METHODS: A randomized control trial was conducted on forty participants (aged between 40-60 years, diagnosed with mild degree pelvic organ prolapse participated in the research. Participants were randomly divided into two groups: (group A; n = 20) and (group B; n = 20). The participants were tested twice, before and after 12 weeks, during which group (A) performed core stability exercises while group (B) received interferential therapy. A modified Oxford grading scale and the perineometer were used to assess how the vaginal squeeze pressure changed. RESULTS: The study’s findings demonstrated that the modified Oxford grading scale values and vaginal squeeze pressure had a non-statistically significant difference (p-value ≥ 0.05) between both groups pre-treatment while had a statistically significant difference (p-value ≤ 0.05) between both groups post-treatment in favor of group A. CONCLUSIONS: It was concluded that both training programs are efficient at strengthening the pelvic floor muscles, but the core stability exercises were more effective

Impact of foot reflexology combined with dietary modification on premenstrual syndrome: A randomized controlled trial

Article accepted.The article will be published here soon.Pending final quality checks

Ternary Ti-Mo-Fe Nanotubes as Efficient Photoanodes for Solar-Assisted Water Splitting

Designing efficient and stable water splitting photocatalysts is an intriguing challenge for energy conversion systems. We report on the optimal fabrication of perfectly aligned nanotubes on trimetallic Ti-Mo-Fe alloy with different compositions prepared via the combination of metallurgical control and facile electrochemical anodization in organic media. The X-ray diffraction (XRD) patterns revealed the presence of composite oxides of anatase TiO2and magnetite Fe3O4with better stability and crystallinity. With the optimal alloy composition Ti-(5.0 atom %) Mo-(5.0 atom %) Fe anodized for 16 h, enhanced conductivity, improved photocatalytic performance, and remarkable stability were achieved in comparison with Ti-(3.0 atom %) Mo-(1.0 atom %) Fe samples. Such optimized nanotube films attained an enhanced photocatalytic activity of ∼0.272 mA/cm2at 0.9 VSCE, which is approximately 4 times compared to the bare TiO2nanotubes fabricated under the same conditions (∼0.041 mA/cm2at 0.9 VSCE). That was mainly correlated with the emergence of Mo and Fe impurities within the lattice, providing excess charge carriers. Meanwhile, the nanotubes showed outstanding stability with a longer electron lifetime. Moreover, carrier density variations, lower charge transfer resistance, and charge carriers dynamics features were demonstrated via the Mott-Schottky and electrochemical impedance analyses

Efficacy and safety of the new generation Watchman FLX device compared to the Watchman 2.5: a systematic review and meta-analysis

Introduction: The first-generation Watchman 2.5 (W 2.5)TM presented several limitations, such as challenges in implantation within complex left atrial appendage (LAA) anatomies, higher incidence of peri-device leak, device recapture, and device-related thrombus (DRT). The newer generation Watchman FLX (W-FLX)TM was introduced with a modified design aiming to overcome these limitations. The purpose of this meta-analysis is to conduct a comparative assessment of the safety and efficacy of the W-FLX and 2.5 devices in clinical practice. Method: The meta-analysis was conducted according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA). Studies were located through a search strategy utilizing PubMed, Cochrane, Google scholar and MEDLINE from inception to March 2023, with a primary objective to compare the safety and efficacy of the W-FLX and W 2.5 devices. After applying the selection criteria, five studies were included in this analysis. Results: The analysis included five studies comprising 54,727 patients. The W-FLX is associated with an increase in procedural success (OR 7.49 [95% CI 1.98-28.26, P = 0.02; I2 = 0%]), and a significant reduction in mortality (OR 0.52 [95% CI 0.51-0.54, P\u3c 0.01; I2 = 0%], major bleeding 0.57 [95% CI 0.51-0.64, P\u3c 0.01; I2 = 0%]), device embolism (OR 0.35 [95% CI 0.18-0.70, P = 0.02; I2 = 0%]), and pericardial effusion (OR 0.33 [95% CI 0.26-0.41, P\u3c 0.01; I2 = 0%]). The rates of DRT and stroke were similar between the two groups. Conclusion: Compared to the W 2.5, the W-FLX was associated with a higher procedural success rate and significantly reduced adverse outcomes including mortality, major bleeding, device embolization, and pericardial effusion