Pectin Nanoporous Structures Prepared via Salt-Induced Phase Separation and Ambient Azeotropic Evaporation Processes.

Polysaccharide nanoporous structures are suitable for various applications, ranging from biomedical scaffolds to adsorption materials, owing to their biocompatibility and large surface areas. Pectin, in particular, can create 3D nanoporous structures in aqueous solutions by binding with calcium cations and creating nanopores by phase separation; this process involves forming hydrogen bonds between alcohols and pectin chains in water and alcohol mixtures and the resulting penetration of alcohols into calcium-bound pectin gels. However, owing to the dehydration and condensation of polysaccharide chains during drying, it has proven to be challenging to maintain the 3D nanoporous structure without using a freeze-drying process or supercritical fluid. Herein, we report a facile method for creating polysaccharide-based xerogels, involving the co-evaporation of water with a nonsolvent (e.g., a low-molecular-weight hydrophobic alcohol such as isopropyl or n-propyl alcohol) at ambient conditions. Experiments and coarse-grained molecular dynamics simulations confirmed that salt-induced phase separation and hydrogen bonding between hydrophobic alcohols and pectin chains were the dominant processes in mixtures of pectin, water, and hydrophobic alcohols. Furthermore, the azeotropic evaporation of water and alcohol mixed in approximately 1:1 molar ratios was maintained during the natural drying process under ambient conditions, preventing the hydration and aggregation of the hydrophilic pectin chains. These results introduce a simple and convenient process to produce 3D polysaccharide xerogels under ambient conditions.

Serratus Anterior Plane Block and Intercostal Nerve Block after Thoracoscopic Surgery.

BACKGROUND: This study aimed to compare the postoperative analgesic effect between ultrasound-guided serratus anterior plane block (Group S, SAPB) and intercostal nerve block (Group I, ICNB) after single port video-assisted thoracoscopic surgery (S-VATS) in primary spontaneous pneumothorax. METHODS: In this prospective randomized controlled study, 54 patients were randomly assigned to two groups. Patients in Group S underwent the SAPB before the surgical drape by an anesthesiologist, and in Group I, ICNBs were performed just before the wound closure after S-VATS by an attending thoracic surgeon. The primary outcome was the numeric pain rating scale (NRS) score given by the patients for pain at the surgical incision site. NRS was assessed during resting and coughing statuses at 3, 6, and 12 hours postoperatively and at the time of the chest tube removal. The secondary outcomes included the number of nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid administration until time to chest tube removal. RESULTS: There were no statistical differences between the two groups regarding age, body mass index, duration of operation, duration of anesthesia, and average NRS scores for the assigned time periods. There was no statistical significance in the number of opioid injections; however, NSAIDs were administered 2.8 times per patient in Group I, and 1.9 times per patient in Group S (p = 0.038). CONCLUSION: In the patients who underwent S-VATS with primary spontaneous pneumothorax, the SAPB provided similar postoperative pain relief with reducing the NSAIDs consumption compared with ICNB.

Encapsulation of a Nerve Agent Detoxifying Enzyme by a Mesoporous Zirconium Metal-Organic Framework Engenders Thermal and Long-Term Stability.

Immobilized enzymes typically have greater thermal and operational stability than their soluble form. Here we report that for the first time, a nerve agent detoxifying enzyme, organophosphorus acid anhydrolase (OPAA), has been successfully encapsulated into a water-stable zirconium metal-organic framework (MOF). This MOF features a hierarchical mesoporous channel structure and exhibits a 12 wt % loading capacity of OPAA. The thermal and long-term stabilities of OPAA are both significantly enhanced after immobilization.

Detoxification of Chemical Warfare Agents Using a Zr6 -Based Metal-Organic Framework/Polymer Mixture.

Owing to their high surface area, periodic distribution of metal sites, and water stability, zirconium-based metal-organic frameworks (Zr6 -MOFs) have shown promising activity for the hydrolysis of nerve agents GD and VX, as well as the simulant, dimethyl 4-nitrophenylphosphate (DMNP), in buffered solutions. A hurdle to using MOFs for this application is the current need for a buffer solution. Here the destruction of the simulant DMNP, as well as the chemical warfare agents (GD and VX) through hydrolysis using a MOF catalyst mixed with a non-volatile, water-insoluble, heterogeneous buffer is reported. The hydrolysis of the simulant and nerve agents in the presence of the heterogeneous buffer was fast and effective.

In situ Generation of Reticulate Micropores through Covalent Network/Polymer Nanocomposite Membranes for Reverse-Selective Separation of Carbon Dioxide.

We demonstrate the synthesis of a microporous covalent-network membrane derived from co-continuous blends of a porogenic urea network and a polyimide (PI). We show that the urea networks in the PI matrix may be thermally rearranged while selectively expelling small molecular fragments, thereby forming a new network bearing reticular microporous molecular pathways. The porous structures enable reverse-selective gas separation, efficiently blocking carbon dioxide to which most polymeric membranes exhibit selective permeability. The proposed method for fabricating microporous organic membranes with highly tunable porosities using a variety of chemical structures and processing parameters is facile and shows promise for the creation of new membrane-based molecular-separation techniques.

Bicontinuous Nanoporous Frameworks: Caged Longevity for Enzymes.

The preparation of bicontinuous nanoporous covalent frameworks, which are promising for caging active enzymes, is demonstrated. The frameworks have three- dimensionally continuous, hydrophilic pores with widths varying between 5 and 30 nm. Enzymes were infiltrated into the bicontinuous pore by applying a pressured enzyme solution. The new materials and methods allowed the amount of caged proteins to be controlled precisely. The resulting enzyme-loaded framework films could be recycled many times with nearly no loss of catalytic activity. Entropic trapping of proteins by a bicontinuous pore with the right size distribution is an unprecedented strategy toward facile in vitro utilization of biocatalysts.

Effective, Facile, and Selective Hydrolysis of the Chemical Warfare Agent VX Using Zr6-Based Metal-Organic Frameworks.

The nerve agent VX is among the most toxic chemicals known to mankind, and robust solutions are needed to rapidly and selectively deactivate it. Herein, we demonstrate that three Zr6-based metal-organic frameworks (MOFs), namely, UiO-67, UiO-67-NH2, and UiO-67-N(Me)2, are selective and highly active catalysts for the hydrolysis of VX. Utilizing UiO-67, UiO-67-NH2, and UiO-67-N(Me)2 in a pH 10 buffered solution of N-ethylmorpholine, selective hydrolysis of the P-S bond in VX was observed. In addition, UiO-67-N(Me)2 was found to catalyze VX hydrolysis with an initial half-life of 1.8 min. This half-life is nearly 3 orders of magnitude shorter than that of the only other MOF tested to date for hydrolysis of VX and rivals the activity of the best nonenzymatic materials. Hydrolysis utilizing Zr-based MOFs is also selective and facile in the absence of pH 10 buffer (just water) and for the destruction of the toxic byproduct EA-2192.

Tailoring the Pore Size and Functionality of UiO-Type Metal-Organic Frameworks for Optimal Nerve Agent Destruction.

Evaluation of UiO-66 and UiO-67 metal-organic framework derivatives as catalysts for the degradation of soman, a chemical warfare agent, showed the importance of both the linker size and functionality. The best catalysts yielded half-lives of less than 1 min. Further testing with a nerve agent simulant established that different rate-assessment techniques yield similar values for degradation half-lives.

Instantaneous hydrolysis of nerve-agent simulants with a six-connected zirconium-based metal-organic framework.

A nerve-agent simulant based on a phosphate ester is hydrolyzed using a MOF-based catalyst. Suspensions of MOF-808 (6-connected), a material featuring 6-connected zirconium nodes, display the highest hydrolysis rates among all MOFs that have been reported to date. A plug-flow reactor was also prepared with MOF-808 (6-connected) as the active layer. Deployed in a simple filtration scheme, the reactor displayed high hydrolysis efficiency and reusability.

Equilibrium shift, poisoning prevention, and selectivity enhancement in catalysis via dehydration of polymeric membranes.

Generation of water as a byproduct in chemical reactions is often detrimental because it lowers the yield of the target product. Although several water removal methods, using absorbents, inorganic membranes, and additional dehydration reactions, have been proposed, there is an increasing demand for a stable and simple system that can selectively remove water over a wide range of reaction temperatures. Herein we report a thermally rearranged polybenzoxazole hollow fiber membrane with good water permselectivity and stability at reaction temperatures of up to 400 °C. Common reaction engineering challenges, such as those due to equilibrium limits, catalyst deactivation, and water-based side reactions, have been addressed using this membrane in a reactor.

Ultrathin Water-Cast Polymer Membranes for Hydrogen Purification.

Among various H2 purification technologies, the use of membrane technology has been considered an ecofriendly approach for addressing the increasing hydrogen demand. Although many H2-selective membrane materials have been reported, processing them into hollow fibers or thin-film composites (TFCs) via traditional methods either affects the performance of the materials or renders their further processing into applicable membrane forms infeasible. Herein, we propose a water-casting method for fabricating TFC membranes for hydrogen purification with high permselectivity. The film integrity and thickness were manipulated by controlling the spreadability of the casting solution, and the resultant water-cast TFC membrane that comprised an ∼30 nm selective layer demonstrated high H2 permeance and H2/CH4 selectivity of approximately 190 GPU and 100, respectively, under optimized conditions. We performed a mixed-gas permeation test using a simulated off-gas of steam-methane reforming from natural gas in a single-stage system and obtained hydrogen gas of >99 mol % purity. This indicates not only the suitability of the water-cast membranes for satisfying the demand for pure hydrogen as a fuel and chemical reagent but also the great potential of the water-casting method for high-performance membranes in various industrial and environmental applications.

Physicochemical and biological properties of four calcium silicate-based endodontic cements.

Background/purpose: Several brands of calcium silicate-based cements (CSBCs) are currently marketed. Here we compared physicochemical and biological properties of new products Ortho MTA (BioMTA), Retro MTA (BioMTA), and EZ-Seal (Ezekiel) to widely used ProRoot MTA (Dentsply Tulsa). Materials and methods: CSBCs were analyzed by X-ray diffractometry and examined by scanning electron microscopy. Elemental composition was determined by energy dispersive spectroscopy. Particle size was measured by particle size analyzer. Human stem cells from apical papilla (SCAPs) were incubated with eluates from CSBCs. Survival of SCAP cells was evaluated with MTT assay. The Alizarin red S stain was used to identify calcified nodules formed in SCAP cultures. The effects of CSBC eluates on SCAP proliferation and migration were examined using an in-vitro scratch "wound-healing" assay. Results: All CSBC specimens showed similar X-ray diffraction patterns. The average particle size of EZ-Seal was smaller than ProRoot MTA, Ortho MTA, and Retro MTA (P < 0.001). The least cytotoxicity of eluates was found for EZ-Seal. In the Alizarin red S staining test, calcified nodules were observed in cultures with ProRoot MTA, Ortho MTA, and Retro MTA, however, no calcified nodules were observed in cultures with EZ-Seal. SCAP proliferation and migration capacity in presence of EZ-Seal was higher than with ProRoot MTA, Ortho MTA, and Retro MTA (P < 0.001). Conclusion: EZ-Seal has a smaller average particle size and a better cytocompatibility than all other examined CSBCs.

Selective CO2 adsorption and bathochromic shift in a phosphocholine-based lipid and conjugated polymer assembly.

We assemble a film of a phosphocholine-based lipid and a crystalline conjugated polymer using hydrophobic interactions between the alkyl tails of the lipid and alkyl side chains of the polymer, and demonstrated its selective gas adsorption properties and the polymer's improved light absorption properties. We show that a strong attractive interaction between the polar lipid heads and CO2 was responsible for 6 times more CO2 being adsorbed onto the assembly than N2, and that with repeated CO2 adsorption and vacuuming procedures, the assembly structures of the lipid-polymer assembly were irreversibly changed, as demonstrated by in situ grazing-incidence X-ray diffraction during the gas adsorption and desorption. Despite the disruption of the lipid structure caused by adsorbed polar gas molecules on polar head groups, gas adsorption could promote orderly alkyl chain packing by inducing compressive strain, resulting in enhanced electron delocalization of conjugated backbones and bathochromic light absorption. The findings suggest that merging the structures of the crystalline functional polymer and lipid bilayer is a viable option for solar energy-converting systems that use conjugated polymers as a light harvester and the polar heads as CO2-capturing sites.

Rearranged Copolyurea Networks for Selective Carbon Dioxide Adsorption at Room Temperature.

Copolyurea networks (co-UNs) were synthesized via crosslinking polymerization of a mixture of tetrakis(4-aminophenyl)methane (TAPM) and melamine with hexamethylene diisocyanate (HDI) using the organic sol-gel polymerization method. The subsequent thermal treatment of between 200 and 400 °C induced the sintering of the powdery polyurea networks to form porous frameworks via urea bond rearrangement and the removal of volatile hexamethylene moieties. Incorporating melamine into the networks resulted in a higher nitrogen content and micropore ratio, whereas the overall porosity decreased with the melamine composition. The rearranged network composed of the tetraamine/melamine units in an 80:20 ratio showed the highest carbon dioxide adsorption quantity at room temperature. The results show that optimizing the chemical structure and porosity of polyurea-based networks can lead to carbon dioxide adsorbents working at elevated temperatures.

Bilateral stellate ganglion block for migraine: A case report.

RATIONALE: Migraine is a recurrent, disabling neurovascular headache disorder. The patient's quality of life can be severely impaired by migraine attacks. Stellate ganglion block (SGB) can be used to relieve pain in the head, neck, and upper extremities. In the present cases, we performed SGB in 2 patients with migraine that responds poorly to drugs. PATIENT CONCERNS: Patients 1 and 2 suffered from chronic, bilateral pulsating headache, accompanied by nausea and vomiting. Patient 1 presented with headache of 8 on the visual analog scale (VAS), and 37 on the migraine disability assessment (MIDAS). Patient 2 reported headache of 7 on the VAS, and 32 on the MIDAS. DIAGNOSIS: The patients were diagnosed with migraine without aura based on the International Classification of Headache Disorders version 3. INTERVENTIONS: Patient 1 was treated with bilateral SGB every week for a month and then every month for 3 months. Patient 2 received bilateral SGB every 2 weeks for a month and then every month for 3 months. OUTCOMES: Four months after SGB, patient 1 reported pain intensity of 4 on VAS and 6 on MIDAS and patient 2 rated pain intensity of 3 on VAS, and 6 on MIDAS, respectively. LESSONS: The SGB can be an effective option to improve headache-related disability and relieve pain intensity in the patients with refractory migraine.

Comparison of the intraoperative analgesic efficacy between ultrasound-guided deep and superficial serratus anterior plane block during video-assisted thoracoscopic lobectomy: A prospective randomized clinical trial.

BACKGROUND: The serratus anterior plane block (SAPB) is a novel method that provides lateral chest wall analgesia. There are 2 methods of SAPB; deep and superficial SAPB. Each of these methods has been demonstrated to provide effective perioperative analgesia in thoracic surgery. The aim of this study was to compare the intraoperative hemodynamic and analgesic benefits of deep versus superficial SAPB during video-assisted thoracic surgery (VATS) lobectomy. METHODS: We performed a prospective, randomized, patient/assessor-blinded trial. We included patients who were 20 to 75 years of age and scheduled to undergo VATS lobectomy with American Society of Anesthesiologists physical status 1 or 2. Patients were randomly allocated to receive either ultrasound-guided deep SAPB (Group D) or superficial SAPB (Group S). The primary outcome was intraoperative remifentanil consumption. We also recorded intraoperative systolic blood pressure (SBP), heart rate (HR), emergence time, and doses of rescue drugs used to manage hemodynamic instability. RESULTS: Data for 50 patients undergoing 3-port VATS lobectomy were analyzed. Intraoperative remifentanil consumption did not differ significantly between Group D (n = 25, 715.62 ±â€Š320.36 µg) and group S (n = 25, 721.08 ±â€Š294.48 µg) (P = .97). Additionally, there were no significant differences between the 2 groups in SBP and HR at any time point, emergence time, or amount of rescue drugs used. CONCLUSION: Our study suggests that the intraoperative analgesic efficacy is similar for deep and superficial SAPB during VATS lobectomy.

Bending resistance and cyclic fatigue resistance of WaveOne Gold, Reciproc Blue, and HyFlex EDM instruments.

BACKGROUND/PURPOSE: Several single-file systems manufactured using different heat treatment and operated by different kinematics have been released. This study compared the bending resistance and cyclic fatigue resistance of three NiTi files, and examined their phase-transformation behavior. MATERIALS AND METHODS: WaveOne Gold Primary (WOG), Reciproc Blue R25 (RPB), and HyFlex EDM OneFile (HDM) were tested (N = 40/instrument). A vertical load was applied to a point 3 mm from the tip, and the stress was measured until a displacement of 3 mm. Tests were conducted at either room temperature (RT: 22 °C) or body temperature (BT: 37 °C) (n = 10). Cyclic fatigue resistance tests were performed in an artificial canal, which had a curvature angle of 40° and a 5-mm radius. Tests were conducted at either RT or BT (n = 10). Instruments were operated according to the manufacturers' instructions. Test results were analyzed using the Kruskal-Wallis and the Mann-Whitney tests. Additional three instruments of each brand were subjected to differential scanning calorimetry (DSC). RESULTS: At RT the bending resistance of three files were not significantly different. However, at BT the bending resistance of RPB was highest, followed by WOG, and HDM (P < 0.05). At RT, RPB demonstrated the longest fracture time, followed by HDM, and WOG (P < 0.05). At BT, HDM had the longest fracture time, followed by RPB, and WOG (P < 0.05). The WOG, RPB consisted of austenite in a considerable proportion, whereas HDM was mainly martensite state at BT. CONCLUSION: HDM presented superior flexibility and cyclic fatigue resistance at BT.

Green and rapid mechanosynthesis of high-porosity NU- and UiO-type metal-organic frameworks.

The use of a dodecanuclear zirconium acetate cluster as a precursor enables the rapid, clean mechanochemical synthesis of high-microporosity metal-organic frameworks NU-901 and UiO-67, with surface areas up to 2250 m2 g-1. Real-time X-ray diffraction monitoring reveals that mechanochemical reactions involving the conventional hexanuclear zirconium methacrylate precursor are hindered by the formation of an inert intermediate, which does not appear when using the dodecanuclear acetate cluster as a reactant.

Comparison of Analgesic Efficacy of Laparoscope-Assisted and Ultrasound-Guided Transversus Abdominis Plane Block after Laparoscopic Colorectal Operation: A Randomized, Single-Blind, Non-Inferiority Trial.

BACKGROUND: Transversus abdominis plane (TAP) block has been used as a component of multimodal analgesia after abdominal operation. We introduced a new laparoscope-assisted TAP (LTAP) block technique using intraperitoneal injection and compared its analgesic effect with that of an ultrasound-guided TAP (UTAP) block in terms of postoperative pain control. STUDY DESIGN: A prospective, randomized, single-blinded non-inferiority clinical trial was conducted with patients undergoing elective laparoscopic colectomy for colon cancer. Eighty patients were randomly assigned (1:1 ratio) to the UTAP and LTAP groups. At the end of the operation, opioid consumption and numeric rating scores (NRS; 0 [no pain] to 10 [worst pain]) of pain were recorded at 2, 6, 24, and 48 hours postoperatively and were compared between the groups. The primary end point was pain NRS during rest at 24 hours after operation. RESULTS: Thirty-eight patients in the LTAP group and 35 patients in the UTAP group completed the study protocol. We found no significant difference in mean ± SD pain NRS during rest at 24 hours between the LTAP group (3.90 ± 1.7) and the UTAP group (4.5 ± 1.9). The mean difference in pain NRS during rest at 24 hours was 0.57 (95% CI -0.26 to 1.41). Because the lower boundary of a 95% CI for the differences in pain NRS was > -1, non-inferiority was established. There was no significant difference between the groups in NRS pain during rest, NRS pain on movement, and postoperative morphine consumption during the 48 hours after operation. CONCLUSIONS: These results show our new LTAP block technique was non-inferior to the ultrasound-guided technique in providing a TAP block after laparoscopic colorectal operation.

Effect of Intravenous High Dose Vitamin C on Postoperative Pain and Morphine Use after Laparoscopic Colectomy: A Randomized Controlled Trial.

Background and Objective. Vitamin C has antioxidant, neuroprotective, and neuromodulating effects. Recently, it showed antinociceptive effect as a result of the antioxidant properties. Therefore, we designed this study to assess the effect of intravenous vitamin C on opiate consumption and pain in patients undergoing laparoscopic colectomy. Methods. A total of 100 patients were enrolled and allocated to receive 50 mg/kg vitamin C or placebo by intravenous infusion immediately after induction of anesthesia. Morphine consumption and scores of pain were assessed at 2, 6, and 24 h after completion of surgery. Results. There were 97 patients included in the analysis. Patients who received vitamin C had higher plasma concentrations of vitamin C at the end of surgery, significantly lower morphine consumption at the 2 h after end of surgery, and significantly lower pain scores at rest during first 24 h postoperatively. There was no significant difference between groups in side effects, fatigue score, or pain score during cough. Conclusion. This study shows high dose vitamin C infusion decreased postoperative pain during the first 24 h and reduced morphine consumption in the early postoperative period. Additional research needed to examine whether higher doses of vitamin C and longer infusion times can amplify these effects.