Electrospun Polyvinylidene Fluoride Membranes: Waterproofing and Acoustic Performance for Air and Acoustic Vents in Electronics.

Advancements in electronic devices demand materials capable of exceptional performance in various challenging environments. This study presents polyvinylidene fluoride (PVDF) nonwoven membranes with controlled porosity, created using an air-guided electrospinning method, followed by a calendaring process. These membranes exhibit a combination of water-repellent properties and sound transmission capabilities, making them ideal candidates for use in air and acoustic vents in electronic systems. A key feature of our membrane is the three-dimensional nanostructured pores, ranging from 0.20 to 0.76 µm, with a mean pore size of 0.51 µm, achieved through the formation of randomly arranged long nanofibers. By employing both experimental and theoretical methods, we achieved impressive performance metrics: air permeability of 0.86 cm3/cm2/s, water contact angles up to 139.3°, and breakthrough pressure as low as 0.27 MPa. Our PVDF nonwoven membranes maintain an optimal balance of stiffness, density, and air permeability, leading to exceptionally low sound transmission loss values ranging between -10 and -40 dBV/Pa, all while preserving their structural integrity. These findings contribute to the development of next-generation waterproof and acoustically permeable membranes, offering enhanced performance capabilities in demanding operational scenarios. This work advances the field of nanomaterials, environmental engineering, and acoustic technologies, with the potential to influence the design of future electronic devices.

Optimal target concentration of remifentanil during cataract surgery with monitored anesthesia care.

STUDY OBJECTIVE: To determine the effect-site target concentration (C(et)) of remifentanil that provides optimal conditions for patients and operators during cataract surgery during monitored anesthesia care using a target controlled infusion (TCI) of propofol and remifentanil. DESIGN: Prospective, randomized, double-blinded study. SETTING: Operating room and postoperative recovery area of a university-affiliated hospital. PATIENTS: 66 adult, ASA physical status I, II, and III patients undergoing cataract surgery. INTERVENTIONS: Group I received C(et) of remifentanil 0.5 ng/mL; Group 2 received C(et) of remifentanil one ng/mL; and Group 3 received C(et) of remifentanil 1.5 ng/mL. After giving TCI propofol (C(et); one µg/mL)-remifentanil, an ophthalmologist administered topical anesthesia. MEASUREMENTS AND MAIN RESULTS: Intraoperative hemodynamics, pain scores, sedation scores, patient satisfaction scores, and operators' satisfaction scores regarding surgical conditions were recorded. No statistical differences in heart rate or mean blood pressure were detected among the three groups during surgery. Pain scores (Group 1: 31.9 ± 17.9 vs. Group 2: 11.8 ± 7.7 and Group 3: 11.8 ± 7.7; P < 0.05) were higher and patient satisfaction scores (Group 1: 4.7 ± 0.8 vs. Group 2: 5.4 ± 0.4 and Group 3: 5.5 ± 0.4; P < 0.05) were lower in Group 1 than Groups 2 and 3. On the other hand, surgeon satisfaction was lowest in Group 3 (Group 3: 2.9 ± 1.3 vs. Group 1: 4.7 ± 0.4 and Group 2: 4.6 ± 0.7; P < 0.05) due to ocular movement. CONCLUSION: C(et) values of remifentanil and propofol of one ng/mL and one µg/mL, respectively, appear to provide optimal conditions for patients and operators during cataract surgery using monitored anesthesia care with TCI.

Ramosetron versus ondansetron for the prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy.

BACKGROUND: Patients undergoing general anesthesia for laparoscopic cholecystectomy are at high risk for postoperative nausea and vomiting (PONV). This study compared ramosetron and ondansetron in terms of efficacy for PONV prevention after laparoscopic cholecystectomy. METHODS: For this study, 120 patients scheduled to undergo laparoscopic cholecystectomy were randomized (in double-blind fashion) to receive 4 mg of ondansetron (group O4, n = 40), 8 mg of ondansetron (group O8, n = 40), or 0.3 mg of ramosetron (group R, n = 40) intravenously after surgery. Postoperative nausea, retching, vomiting, pain, and side effects were assessed at 2 h, 24 h, and 48 h after surgery. RESULTS: No statistical differences were observed among the three groups with regard to patient characteristics and information on surgery and anesthesia. The ratio of complete response (no PONV for 2 h) was higher for groups O8 and R than for group O4 as follows: 80% (n = 32) for groups O8 and R versus 58% (n = 23) for group O4 during the first postoperative 2 h (p = 0.04), 90% (n = 36) for groups O8 and R versus 76% (n = 30) for group O4 over 24 h (2-24 h) (p = 0.09), and 98% (n = 38) for groups O4 and O8 versus 100% (n = 40) for group R over the next 24 h (24-48 h) after surgery (p = 0.36). During the first 2 h after surgery, rescue antiemetics were used for significantly fewer patients in groups O8 and R (20%) than in group O4 (42.5%) (p = 0.04). Postoperative pain and the use of rescue analgesics were comparable among the groups. There was no clinically serious adverse event due to the study drugs. CONCLUSION: Ramosetron 0.3 mg and ondansetron 8 mg are more effective than ondansetron 4 mg for the prevention of PONV (2 h). Ramosetron 0.3 mg is as effective as ondansetron 8 mg for the prophylaxis of PONV after laparoscopic cholecystectomy.

Effect of midazolam premedication on the onset of propofol and rocuronium during propofol target-controlled infusion.

BACKGROUND: This clinical study was designed to evaluate the effect of midazolam as a premedication on the onset of propofol and rocuronium during propofol target-controlled infusion (TCI). METHODS: Seventy four patients (ASA class I or II) were randomly allocated to receive either no premedication (control group) or premedication with 0.04 mg/kg intravenous midazolam (midazolam group). Anesthesia was induced and maintained with propofol TCI. Time from propofol injection to loss of consciousness (LOC) and estimated effect concentration at LOC were recorded. After LOC, rocuronium (0.6 mg/kg) was injected. We monitored the degree of neuromuscular blockade by acceleromyography. The following parameters were measured and compared between groups: Time from rocuronium injection to depression of twitch height below 25%, time to maximal depression of twitch height (defined as rocuronium onset time). RESULTS: Systolic blood pressure before induction was lower in midazolam group (125 +/- 15 vs 135 +/- 20 mmHg), however, there was no difference in blood pressure at LOC between groups (111 +/- 16 vs 106 +/- 21 mmHg). In midazolam group, time to LOC in propofol TCI was shorter (63 +/- 22 vs. 203 +/- 118 sec) and estimated effect site concentration of propofol was significantly lower than control group (0.9 +/- 0.3 vs. 2.2 +/- 0.4 microl/ml). The onset time of rocuronium was not different between groups (120 +/- 39 vs. 137 +/- 42 sec). CONCLUSIONS: Midazolam pretreatment fastens the onset time of propofol and decreases the propofol requirement for LOC. However, it does not influence the onset of rocuronium.