Time-resolved spectroscopic investigation for the practical application of a photocatalytic air purifier.

The photocatalytic efficiency for removing volatile organic compounds (VOCs) is significantly influenced by operational parameters like humidity and flow velocity, exhibiting notable and inconsistent fluctuations in both lab-scale and large-scale demonstrations. In this study, operando spectroscopy and isotope analysis were employed to investigate the correlation between humidity levels and degradation of gaseous acetaldehyde using TiO2 photocatalysts, aiming to demonstrate the scaling-up of photocatalytic air purifier. It was observed that rate constants for the mineralization of acetaldehyde rapidly decreased by 30% as relative humidity increased from 25% to 80% in the flow system (with an air velocity, v = 0.78 m/s). However, batch system showed smaller change with only a 10% reduction of the rate constant. Humidity fluctuations were more pronounced under high-speed conditions and were amplified in air purifier (v = 3.8 m/s). Time-resolved operando spectroscopy using an 13C isotope of acetaldehyde revealed that humidity's distinct role in dark adsorption and photocatalytic reactions. Water was found to inhibit the formation of crotonaldehyde during aldol condensation reaction in dark condition. Moreover, water suppressed photocatalytic mineralization by inhibiting acetate oxidation to formate. These findings provide valuable insights for improving realistic air purification processes, underscoring the importance of identifying key intermediates and controlling humidity to enhance the selectivity of gaseous pollutant oxidation reactions.

Long-lifetime water-washable ceramic catalyst filter for air purification.

Particulate matter (PM) and volatile organic compounds (VOCs) are recognised as hazardous air pollutants threatening human health. Disposable filters are generally used for air purification despite frequent replacement and waste generation problems. However, the development of a novel regenerable and robust filter for long-term use is a huge challenge. Here, we report on a new class of facile water-washing regenerable ceramic catalyst filters (CCFs), developed to simultaneously remove PM (>95%) and VOCs (>82%) in single-pass and maximized space efficiency by coating the inner and outer filter channels with an inorganic membrane and a Cu2O/TiO2 photocatalyst, respectively. The CCFs reveal four-fold increase in the maximum dust loading capacity (approximately 20 g/L) in relation to conventional filters (5 g/L), and can be reused after ten regeneration capability with simple water washing retaining initial PM and VOC removal performances. Thus, the CCFs can be well-suited for indoor and outdoor air purification for 20 years, which shows a huge increase in lifetime compared to the 6-month lifespan of conventional filters. Finally, we believe that the development and implementation of CCFs for air purification can open new avenues for sustainable technology through renewability and zero-waste generation.

Analgesic effect of ropivacaine with fentanyl in comparison with ropivacaine alone for continuous femoral nerve block after knee replacement arthroplasty: a prospective, randomized, double-blinded study.

BACKGROUND: The analgesic effect of perineural opioid in clinical practice are still controversial. This randomized controlled trial compared analgesic effect of ropivacaine with fentanyl or ropivacaine alone for continuous femoral nerve block following unilateral total knee arthroplasty. METHODS: Fourty patients of ASA PS Ⅰ or Ⅱ receiving total knee arthroplasty with spinal anesthesia were enlisted and randomly allocated into two groups. Group R; bolus injection of 0.375% ropivacaine, 30 ml and an infusion of 0.2% ropivacaine at 8 ml/h (n = 20). Group RF; 0.375% ropivacaine, 29 ml added with 50 µg of fentanyl as a bolus and an infusion of 0.2% ropivacaine mixed with 1 µg/ml of fentanyl at 8 ml/h (n = 20). Local anesthetic infusion via a femoral nerve catheter was started at the end of operation and continued for 48 h. Intravenous patient-controlled analgesia with hydromorphone (0.15 mg/ml, 0-1-10) were used for adjuvant analgesics. Position of catheter tip and contrast distribution, visual analogue scale of pain, hydromorphone consumption, side effects were recorded for 48 h after operation. Patient satisfaction for the pain control received were noted. RESULTS: The pain visual analogue scale, incidences of side effects and satisfaction were not different between the two groups (P > 0.05), but the hydromorphone usage at 48 h after operation were lower in the Group RF than in the Group R (P = 0.047). CONCLUSIONS: The analgesic effect of ropivacaine with fentanyl for continuous femoral nerve block after knee replacement arthroplasty was not superior to that of the ropivacaine alone.

Uniform-thickness electrospun nanofiber mat production system based on real-time thickness measurement.

Electrospinning is a simple versatile process used to produce nanofibers and collect them as a nanofiber mat. However, due to bending instability, electrospinning often produces a nanofiber mat with non-uniform mat thickness. In this study, we developed a uniform-thickness electrospun nanofiber mat (UTEN) production system with a movable collector based on real-time thickness measurement and thickness feedback control. This system is compatible with a collector with void regions such as a mesh-type collector, two-parallel-metal-plate collector, and ring-type collector, which facilitates the measurement of light transmittance across the produced nanofiber mat during electrospinning. A real-time measurement system was developed to measure light transmittance and convert it to the thickness of the nanofiber mat in real time using the Beer-Lambert law. Thickness feedback control was achieved by repeating the following sequences: (1) finding an optimal position of the movable collector based on the measured thickness of the nanofiber mat, (2) shifting the collector to an optimal position, and (3) performing electrospinning for a given time step. We found that the suggested thickness feedback control algorithm could significantly decrease the non-uniformity of the nanofiber mat by reducing the standard deviation by more than 8 and 3 times for the numerical simulation and experiments, respectively, when compared with the conventional electrospinning. As a pioneering research, this study will contribute to the development of an electrospinning system to produce robust and reliable nanofiber mats in many research and industrial fields such as biomedicine, environment, and energy.

In Situ Photoelectrochemical Chloride Activation Using a WO3 Electrode for Oxidative Treatment with Simultaneous H2 Evolution under Visible Light.

Reactive chlorine species (RCS) such as HOCl and chlorine radical species is a strong oxidant and has been widely used for water disinfection. This study investigated a photoelectrochemical (PEC) method of RCS production from ubiquitous chloride ions using a WO3 film electrode and visible light. The degradation of organic substrates coupled with H2 evolution using a WO3 electrode was compared among electrochemical (EC), photocatalytic (PC), and PEC conditions (potential bias: +0.5 V vs Ag/AgCl; λ > 420 nm). The degradation of 4-chlorophenol, bisphenol A, acetaminophen, carbamazepine, humic acid, and fulvic acid and the inactivation of E. coli were remarkably enhanced by in situ RCS generated in PEC conditions, whereas the activities of the PC and EC processes were negligible. The activities of the WO3 film were limited by rapid charge recombination in the PC condition, and the potential bias of +0.5 V did not induce any significant reactions in the EC condition. The PEC activities of WO3 were limited in the absence of Cl- but significantly enhanced in the presence of Cl-, which confirmed the essential role of RCS in this PEC system. The PEC mineralization of organic compounds was also markedly enhanced in the presence of Cl- where dark chemical chlorination by NaOCl addition induced a negligible mineralization. The H2 generation was observed only at the PEC condition and was negligible at PC and EC conditions. On the other hand, the oxidation of chloride on a WO3 photoanode produced chlorate (ClO3-) as a toxic byproduct under UV irradiation, but the visible light-irradiated PEC system generated no chlorate.

Anaphylactic shock after sugammadex administration, induced by formation of a sugammadex-rocuronium complex -a case report.

BACKGROUND: Sugammadex is a reversal agent for non-depolarizing neuromuscular blockers and widely used worldwide on account of its rapid and effective reversal from neuromuscular blockade, despite its advantages, multiple cases of sugammadex-induced anaphylactic shock have been reported. CASE: A 42-year-old man developed anaphylactic shock in the postanesthesia care unit. Initially, sugammadex was suspected as the causative agent, but an intradermal skin test revealed negative results. A further skin test was performed with sugammadex-rocuronium complex that yielded positive results. CONCLUSIONS: Anesthesiologists and healthcare providers should be aware of the possibility of anaphylaxis from the sugammadex-rocuronium complex, as well as from sugammadex or rocuronium alone.

Photoelectrochemical Degradation of Organic Compounds Coupled with Molecular Hydrogen Generation Using Electrochromic TiO2 Nanotube Arrays.

Vertically aligned TiO2 nanotube arrays (TNTs) were prepared by electrochemical anodization, and then cathodically polarized with dark blue coloration for the dual-functional photoelectrochemical water treatment of organic substrates degradation and accompanying H2 generation. The resulting Blue-TNTs (inner diameter: ∼40 nm; length: ∼9 µm) showed negligible shift in X-ray diffraction pattern compared with the intact TNTs, but the X-ray photoelectron spectra indicated a partial reduction of Ti4+ to Ti3+ on the surface. The electrochemical analyses of Blue-TNTs revealed a marked enhancement in donor density and electrical conductivity by orders of magnitude. Degradations of test organic substrates on Blue-TNTs were compared with the intact TNTs in electrochemical (EC), photocatalytic (PC), and photoelectrochemical (PEC) conditions (potential bias: 1.64 VNHE; λ > 320 nm). The degradation of 4-chlorophenol was greatly enhanced on Blue-TNTs particularly in PEC condition, whereas the PC activities of the Blue- and intact TNTs were similar. The potential bias of 1.64 VNHE did not induce any noticeable activity in EC condition. Similar trends were observed for the degradation of humic acid and fulvic acid, where main working oxidants were found to be the surface hydroxyl radical as confirmed by hydroxyl radical probe and scavenger tests. H2 generation coupled with the organic degradation was observed only in PEC condition, where the H2 generation rate with Blue-TNTs was more than doubled from that of intact TNTs. Such superior PEC activity was not observed when a common TiO2 nanoparticle film was used as a photoanode. The enhanced electric conductivity of Blue-TNTs coupled with a proper band bending in PEC configuration seemed to induce a highly synergic enhancement.

Sequential Process Combination of Photocatalytic Oxidation and Dark Reduction for the Removal of Organic Pollutants and Cr(VI) using Ag/TiO2.

We investigated a sequential photocatalysis-dark reaction, wherein organic pollutants were degraded on Ag/TiO2 under UV irradiation and the dark reduction of hexavalent chromium (Cr(VI)) was subsequently followed. The photocatalytic oxidation of 4-chlorophenol (4-CP), a test organic substrate, induced the generation of degradation intermediates and the storage of electrons in Ag/TiO2 which were then utilized for reducing Cr(VI) in the postirradiation period. The dark reduction efficiency of Cr(VI) was much higher with Ag/TiO2 (87%), compared with bare TiO2 (27%) and Pt/TiO2 (22%). The Cr(VI) removal by Ag/TiO2 (87%) was contributed by adsorption (31%), chemical reduction by intermediates of 4-CP degradation (26%), and reduction by electrons stored in Ag (30%). When formic acid, humic acid or ethanol was used as an alternative organic substrate, the electron storage effect was also observed. The postirradiation removal of Cr(VI) on Ag/TiO2 continued for hours, which is consistent with the observation that a residual potential persisted on the Ag/TiO2 electrode in the dark whereas little residual potential was observed on bare TiO2 and Pt/TiO2 electrodes. The stored electrons in Ag/TiO2 and their transfer to Cr(VI) were also indicated by the UV-visible absorption spectral change. Moreover, the electrons stored in the preirradiated Ag/TiO2 reacted with O2 with showing a sign of low-level OH radical generation in the dark period.

Comparison of intubation times using a manikin with an immobilized cervical spine: Macintosh laryngoscope vs. GlideScope vs. fiberoptic bronchoscope.

OBJECTIVE: Airway management in patients with suspected cervical spine injury is classified as a "difficult airway." The best device for managing difficult airways is not known. Therefore, we conducted an intubation study simulating patients with cervical spine injury using three devices: a conventional Macintosh laryngoscope, a video laryngoscope (GlideScope), and a fiberoptic bronchoscope (MAF-TM). Success rates, intubation time, and complication rates were compared. METHODS: Nine physician experts in airway management participated in this study. Cervical immobilization was used to simulate a difficult airway. Each participant performed intubation using airway devices in a randomly chosen order. We measured the time to vocal cord visualization, time to endotracheal tube insertion, and total tracheal intubation time. Success rates and dental injury rates were compared between devices. RESULTS: Total tracheal intubation time using the Macintosh laryngoscope, GlideScope, and fiberoptic bronchoscope was 13.3 (range, 11.1 to 20.1), 14.9 (range, 12.7 to 22.3), and 19.4 seconds (range, 14.1 to 32.5), respectively. Total tracheal intubation time differed significantly among the devices (P=0.009). Success rates for the Macintosh laryngoscope, GlideScope, and fiberoptic bronchoscope were 98%, 96%, and 100%, respectively, and dental injury rates were 5%, 19%, and 0%, respectively. CONCLUSION: The fiberoptic bronchoscope required longer intubation times than the other devices. However, this device had the best success rate with the least incidence of dental injury.

The effects of the Trendelenburg position and intrathoracic pressure on the subclavian cross-sectional area and distance from the subclavian vein to pleura in anesthetized patients.

BACKGROUND: The effects of maneuvers to increase intrathoracic pressure and of Trendelenburg position on the cross-sectional area (CSA) of the subclavian vein (SCV) and the relationship between the SCV and adjacent structures have not been investigated. METHODS: In ultrasonography-guided SCV catheterization (N = 30), the CSA of the SCV and the distance between the SCV and pleura (DSCV-pleura) were determined during 10-second airway opening, and 10-second positive inspiratory hold with 20 cm H2O in the supine position (S-0, and S-20) and the 10° Trendelenburg position (T-0, and T-20). In addition to a statistical significance of P < 0.05, CSA and DSCV-pleura differences of ≥15% were defined as clinically relevant changes. RESULTS: CSA (mean [95% confidence interval]) in S-20, T-0, and T-20 (1.02 [0.95-1.14] cm(2), 1.04 [0.95-1.15] cm(2), and 1.14 [1.04-1.24] cm(2), respectively) was significantly larger than a CSA in S-0 (0.93 [0.86-1.00] cm(2), all P < 0.001). However, only the increase of CSA in T-20 vs S-0 (0.21 cm(2), 23.2%) was clinically meaningful (≥15%). The number of patients who showed CSA increase ≥15% was more in S-0 to T-20 (57%) compared with those in S-0 to S-20 (23%) and S-0 to T-0 (27%). DSCV-pleura measurements (mean) in S-20 and T-20 (0.61 and 0.60 cm) were significantly shorter than those in S-0 (0.70 cm, all P < 0.001), but the reductions of DSCV-pleura were not clinically meaningful (≥15%). CONCLUSIONS: The combined application of inspiratory hold and Trendelenburg position provided a greater and more relevant degree of CSA increase without compromising DSCV-pleura, which may facilitate SCV catheterization. Further investigations are needed to determine whether these results affect the success rate of catheterization and the risk of procedural injury.

Antiemetic efficacy of capsicum plaster on acupuncture points in patients undergoing thyroid operation.

BACKGROUND: Postoperative nausea and vomiting (PONV) occurs in up to 63-84% of patients after thyroid surgery. This study aims to assess the effects of using a capsicum plaster to reduce PONV after thyroid surgery at either the Chinese acupuncture point (acupoint) Pericardium 6 (P6) or Korean hand acupuncture point K-D2. METHODS: One-hundred eighty-four patients who underwent thyroid surgery were randomized in four groups (n = 46 each): control group = inactive tape at P6 acupoints and on both shoulders as a nonacupoint; P6 group = capsicum plaster at P6 points and inactive tape on both shoulders; K-D2 group = capsicum plaster at K-D2 acupoints and inactive tape on both shoulders; Sham group = capsicum plaster on both shoulders and inactive tape at P6 acupoints. The capsicum plaster was applied before the induction of anesthesia and removed at 8 hr after surgery. RESULTS: The incidence and severity of nausea and vomiting and the need for rescue antiemetics were decreased in the patients in the P6 and K-D2 groups compared to the patients in the control and sham groups (P < 0.001). The patients in the P6 and K-D2 groups also reported that they were more satisfied (P < 0.05). CONCLUSIONS: We conclude that the capsicum plaster at the P6 and K-D2 acupoint was a promising antiemetic method for the patients undergoing thyroid surgery.

Rocuronium-induced neuromuscular block after long pretreatment of clonidine in rabbits.

BACKGROUND: Clonidine, an α-2 adrenergic agonist, is used in the perioperative period and in intensive care for the management of hypertension. The in vivo and in vitro effects of clonidine on the actions of nondepolarizing neuromuscular blocking drugs are conflicting. We evaluated the potency and time course of rocuronium-induced neuromuscular block after prolonged pretreatment with clonidine in rabbits. METHODS: Sixty rabbits were randomly assigned to three groups; control (C) group: normal saline 0.1 ml/kg daily subcutaneous for 6 weeks; S3 group: clonidine 4 µg/kg daily subcutaneous for 3 weeks; S6 group: clonidine 4 µg/kg daily subcutaneous for 6 weeks. The dose-response relations of rocuronium were tested in 30 rabbits (10 from each of the three groups) during ketamine-thiopental anesthesia, while the time course of rocuronium 0.6 mg/kg was examined in 10 rabbits each from the three groups. RESULTS: There was no difference in mean arterial pressure and pulse rate among the experimental groups. The calculated ED(50) for rocuronium decreased significantly from 64.1 µg/kg (C group) to 50.3 µg/kg (S3 group) and 47.8µg/kg (S6 group) (P < 0.001). There was no difference in the onset and the recovery times after rocuronium. CONCLUSIONS: Rocuronium after pretreatment with clonidine for three or six weeks may have an increased effect, but no difference in the duration of action compared with control group.

Clinical factors affecting the pain on injection of propofol.

BACKGROUND: Pain on propofol injection is a well-known adverse effect. We evaluated the clinical factors that affect the pain on injection of propofol to develop a strategy to prevent or reduce pain. METHODS: We conducted a prospective, observational study of 207 adult patients (ASA I-II), and the patients were classified according to gender, age, the body mass index (BMI), the IV site and the side of the IV site. During the 10 seconds after propofol injection, pain intensity was measured on an 11-point numerical rating scale (0 = no pain and 10 = worst possible pain). Pain in excess of 3 on the numerical scale was regarded as moderate to severe pain. RESULTS: THE SUBGROUPS OF GENDER (FEMALE: 55.6% vs. male: 25.0%; P < 0.01) and the IV site (dorsum of hand: 61.2% vs. wrist: 40.0% vs. antecubital fossa: 22.5%; P < 0.01) had significantly different frequencies for the incidence of pain on injection on the univariate and multivariate analyses. For the subgroup of females, the incidence of pain was statistically different according to the age group (20-40 yr: 71.0% vs. 41-60: 54.8% vs. 61-80: 38.5%; P = 0.014). CONCLUSIONS: Our results showed that the younger age patients, the patients with a peripheral IV site and female patients are more sensitive to pain on the injection of propofol.

Meningitis after a combined spinal epidural anesthesia: A case report.

The incidence of post-dural puncture meningitis is very low. A 44-year-old patient developed a fever (38degrees C, headache, neck stiffness, nausea, and vomiting after combined spinal epidural (CSE) anesthesia and surgery for closed reduction and internal fixation (CRIF) with intramedullary (IM) nailing, tibia, Rt. With a preliminary diagnosis of bacterial meningitis, empiric broad spectrum antimicrobial treatment was immediately started after cerebrospinal fluid (CSF) sampling. The CSF was clear and revealed a white blood cell count, protein, glucose, and pressure of 146/micrometer, 225 mg/dl, 48 mg/dl (serum 151 mg/dl), and 26 cmH2O, respectively. The CSF stain and culture were negative. Considering the injection of preventive antibiotics before CSE anesthesia, partially treated bacterial meningitis was suspected. Four weeks later, clinical symptoms had improved before the patient was discharged.

The hemodynamic effects of a reversed Trendelenburg in elderly patients with increased cardiac risk during laparoscopic cholecystectomy.

BACKGROUND: We studied the hemodynamic changes induced by pneumoperitoneum and a reversed Trendelenburg in elderly patients with increased cardiac risk (ASA class III; n = 30; age 70.8 +/- 4.9 years, mean +/- SD) and compared the results with elderly patients at normal risk (ASA class II; n = 30; age 69.2 +/- 4.1 years) during laparoscopic cholecystectomy. METHODS: The transesophageal Doppler monitor was performed after induction of general anesthesia (pre-incision), after onset of pneumoperitoneum (insufflation), after head-up (20degrees) and a left lateral tilt (15degrees) (reversed Trendelenburg) and after deflation and horizontal position (desufflation). Mean arterial pressure (MAP), heart rate, cardiac index (CI) and systemic vascular resistance (SVR) were measured, respectively. RESULTS: Induction of pneumoperitoneum and head-up tilt in patients with cardiac risk resulted significantly in a decrease in CI and an increase in SVR compared with patients with normal risk (P < 0.05), and that remained until deflation, but no interval changes in MAP and heart rate. The CI, MAP and heart rate decreased and SVR increased significantly in patients with cardiac risk compared with patients with normal risk before incision (P < 0.05). No complications occurred. The results indicate that pneumoperitoneum and a reversed Trendelenburg are associated with significant but relatively benign hemodynamic changes. CONCLUSIONS: Anesthesia for laparoscopic cholecystectomy in elderly patients with increased cardiac risk should be performed with an adequate hemodynamic monitoring.