Distinct Transcriptional Profiles in the Different Phenotypes of Neurofibroma from the Same Subject with Neurofibromatosis 1.

Neurofibromatosis 1 is a prevalent hereditary neurocutaneous disorder. Among the clinical phenotypes of neurofibromatosis 1, cutaneous neurofibroma (cNF) and plexiform neurofibroma (pNF) have distinct clinical manifestations, and pNF should be closely monitored owing to its malignant potential. However, the detailed distinct features of neurofibromatosis 1 phenotypes remain unknown. To determine whether the transcriptional features and microenvironment of cNF and pNF differ, single-cell RNA sequencing was performed on isolated cNF and pNF cells from the same patient. Six cNF and five pNF specimens from different subjects were also immunohistochemically analyzed. Our findings revealed that cNF and pNF had distinct transcriptional profiles even within the same subject. pNF is enriched in Schwann cells with characteristics similar to those of their malignant counterpart, fibroblasts, with a cancer-associated fibroblast-like phenotype, angiogenic endothelial cells, and M2-like macrophages, whereas cNF is enriched in CD8 T cells with tissue residency markers. The results of immunohistochemical analyses performed on different subjects agreed with those of single-cell RNA sequencing. This study found that cNF and pNF, the different neurofibromatosis phenotypes in neurofibromatosis 1, from the same subject are transcriptionally distinct in terms of the cell types involved, including T cells.

The Rehabilitative Effect of Archery Exercise Intervention in Patients with Parkinson's Disease.

Background: Archery exercise exerts a rehabilitative effect on patients with paraplegia and might potentially serve as complementary physiotherapy for patients with Parkinson's disease. Objective: This study aimed to examine the rehabilitative effects of an archery intervention. Methods: A randomized controlled trial of a 12-week intervention was performed in patients with idiopathic Parkinson's disease. Thirty-one of the 39 eligible patients recruited from a medical center in Taiwan participated in the trial, of whom 16 were in the experimental group practicing archery exercises and 15 were in the control group at the beginning; twenty-nine completed the whole process. The Purdue pegboard test (PPT), the Unified Parkinson's Disease Rating Scale I to III (UPDRS I to III), physical fitness test, and timed up and go test (TUG) were used to assess the intervention effects of archery exercise. Results: Compared to the control group, the outcome differences between the posthoc and baseline tests in PPT, UPDRS I to III, lower extremity muscular strength, and TUG in the experimental group (between-group difference in difference's mean: 2.07, 1.59, 1.36, -2.25, -3.81, -9.10, 3.57, and -1.51, respectively) did show positive changes and their effect sizes examined from Mann-Whitney U tests (η: 0.631, 0.544, 0.555, 0.372, 0.411, 0.470, 0.601, and 0.381, respectively; Ps < 0.05) were medium to large, indicating that the archery intervention exerted promising effects on improving hand flexibility and finger dexterity, activity functions in motor movement, lower extremity muscular strength, and gait and balance ability. Conclusions: Traditional archery exercise was suggested to have a rehabilitative effect for mild to moderate Parkinson's disease and could be a form of physiotherapy. Nevertheless, studies with larger sample sizes and extended intervention periods are needed to ascertain the long-term effects of archery exercise.

Accuracy and eligibility of Bonwill⁃Hawley arch form established by CBCT image for dental crowding measurement: a comparative study with the conventional brass wire and caliper methods.

OBJECTIVES: The purpose of this study was to develop a novel Bonwill⁃Hawley method (Bonwill⁃Hawley arch form based on CBCT image) for the assessment of dental crowding, and to investigate and compare the accuracy and eligibility with the conventional brass wire and caliper methods under different crowding conditions. MATERIAL AND METHODS: Sixty patients with the pair of plaster casts and CBCT data were collected. All the casts were marked and transformed into digital models using iTero scanner, and imported into OrthoCAD software to measure the required space. Using the conventional brass wire (M1) and caliper methods (M2), the available space and dental crowding were measured and calculated basing on digital models, respectively. Correspondingly, the axial planes in the level of dental arches were oriented and captured from the CBCT images to draw the Bonwill⁃Hawley arch forms (M3), which were used to measure and calculate the available space and dental crowding. For each method, intra and inter-examiner reliabilities were evaluated with intra-class correlation coefficients (ICCs). Wilcoxon test and Kruskal-Wallis test were performed for statistically analyzing the discrepancy among different groups. RESULTS: Both intra- and inter-examiner reliability were generally excellent for all parameters obtained by the three methods, except for the dental crowding measured using M1(ICC: 0.473/0.261). The dental crowding measured using M2 were significantly increased in mild, moderate and severe-crowding groups compared with M1. However, no significant difference was detected between M1 and M3 in severe-crowding group (maxilla, p = 0.108 > 0.05; mandible, p = 0.074 > 0.05). With the deterioration of crowding condition, the discrepancy of dental crowding between M1 and M2, or M1 and M3 were significantly decreased (maxilla, M2-M1, mild VS serve, p = 0.003 < 0.05; maxilla, M3-M1, mild VS serve, p = 0.003 < 0.05; mandible, M2-M1, mild VS serve, p = 0.000 < 0.001; mandible, M3-M1, mild VS serve, p = 0.043 < 0.05). CONCLUSION: Dental crowding measured using the novel Bonwill⁃Hawley method was relatively greater than the caliper method, but not exceeding the brass wire method, which wound gradually come close to the brass wire method with the deterioration of crowding condition. CLINICAL RELEVANCE: The Bonwill⁃Hawley method basing on CBCT image proved to be a reliable and acceptable choice for orthodontists to analyze the dental crowding.

Association between Respiratory Function and Motor Function in Different Stages of Parkinson's Disease.

INTRODUCTION: Respiratory dysfunction in patients with Parkinson's disease (PD) could present in the early stage and worsen in the late stages. These changes could be a factor affecting the ability of daily living and quality of life of patients with PD. The primary objective of this study was to assess the respiratory function and its association with motor function in patients with different stages of PD. METHODS: This was a cross-sectional study conducted at the Huashan Hospital of Fudan University in Shanghai, China. The study included 65 patients diagnosed with PD (the Hoehn and Yahr scale between 1 and 4) and 20 healthy individuals of similar age, gender, weight, and height. The ventilatory function was assessed using the spirometry. Motor function was evaluated using subscale III of the United Parkinson's disease rating scale (UPDRS-III). After confirming the normality of data distribution, we performed one-way ANOVA with a Tukey's post hoc test. RESULTS: Compared with the healthy individuals, there was no statistical significance in forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) in the H&Y 1 group and H&Y 2 group (p > 0.05) but reduced peak expiratory flow (PEF) in the H&Y 2 group (p = 0.002). Reduced FVC, FEV1, and PEF was seen in the H&Y 3 group (p = 0.002, p = 0.001, and p = 0.0001, respectively). Reduced FVC, FEV1, PEF, and FEF25-75% was seen in the H&Y 4 group (p = 0.001, p = 0.0001, p = 0.0001, and p = 0.025, respectively). The correlation analysis revealed that there was a significant negative correlation between FVC and UPDRS-III scores (r = -0.248, p = 0.046), disease duration (r = -0.276, p = 0.026), H&Y scale (r = -0.415, p = 0.001). FEV1 was negatively correlated with UPDRS-III scores (r = -0.277, p = 0.025), disease duration (r = -0.291, p = 0.019), H&Y scale (r = -0.434, p = 0.0001). FEF25-75% was negatively correlated with disease duration (r = -0.247, p = 0.047), H&Y scale (r = -0.278, p = 0.025). CONCLUSION: Our findings revealed that respiratory impairment is present in moderate and advanced PD patients, and directly related to the severity of the disease. It is important to conduct respiratory function test in the clinical practice.

Rapid membrane surface functionalization with Ag nanoparticles via coupling electrospray and polymeric solvent bonding for enhanced antifouling and catalytic performance: Deposition and interfacial reaction mechanisms.

Electrospray is an effective, fast, and potentially scalable approach for membrane surface functionalization using various engineered nanomaterials (ENMs). However, the lack of fundamental understandings of the deposition process hinders the controlled deposition, efficient utilization, and long-term stabilization of the ENMs, and thus the practical applications of the nanocomposite membranes. To bridge this critical knowledge gap, advanced online characterization techniques (laser diffraction size measurement and laser doppler velocimetry) coupled with mathematical aerosol modeling are utilized to understand the three key process parameters: droplet size, deposition velocity, and evaporation rate. After deposition, polymeric solvent bonding (i.e., interdiffusion and subsequent entanglement of polymers) was found to substantially stabilize the deposited Ag NPs. We further provide a comprehensive description of such interfacial reaction mechanisms. Our results show a consistency between theoretical predication and measurement of the droplet size or deposition velocity, whereas realistic droplet evaporation rate is lower than the theoretical value due to the addition of the polymer. Successful stabilization of Ag NPs via interfacial polymeric bonding occurs under the conditions of large material contact area, high material compatibility, proper temperature (e.g., 22 °C), and polymer-to-solvent ratio (e.g., 3-5%). Our coupled approach achieves superior Ag NP coverage with high stability within minutes. Despite some reduction in water permeance, the resultant membrane shows markedly improved catalytic and antimicrobial (antibiofouling) performance (>90% enhancement) and maintained rejection. Taken together, our findings provide fundamental insights into the coupled process of electrospray deposition and polymeric solvent bonding to enable additive manufacturing of novel nanocomposite membranes with diverse structures and multiple functions.

Energy Achievement Rate Is an Independent Factor Associated with Intensive Care Unit Mortality in High-Nutritional-Risk Patients with Acute Respiratory Distress Syndrome Requiring Prolonged Prone Positioning Therapy.

Early enteral nutrition (EN) and a nutrition target >60% are recommended for patients in the intensive care unit (ICU), even for those with acute respiratory distress syndrome (ARDS). Prolonged prone positioning (PP) therapy (>48 h) is the rescue therapy of ARDS, but it may worsen the feeding status because it requires the heavy sedation and total paralysis of patients. Our previous studies demonstrated that energy achievement rate (EAR) >65% was a good prognostic factor in ICU. However, its impact on the mortality of patients with ARDS requiring prolonged PP therapy remains unclear. We retrospectively analyzed 79 patients with high nutritional risk (modified nutrition risk in the critically ill; mNUTRIC score ≥5); and identified factors associated with ICU mortality by using a Cox regression model. Through univariate analysis, mNUTRIC score, comorbid with malignancy, actual energy intake, and EAR (%) were associated with ICU mortality. By multivariate analysis, EAR (%) was a strong predictive factor of ICU mortality (HR: 0.19, 95% CI: 0.07-0.56). EAR >65% was associated with lower 14-day, 28-day, and ICU mortality after adjustment for confounding factors. We suggest early EN and increase EAR >65% may benefit patients with ARDS who required prolonged PP therapy.

The Muscle Activation Differences in Post-Stroke Upper Limb Flexion Synergy Based on Spinal Cord Segments: A Preliminary Proof-of-Concept Study.

Objective: This study examined the activation difference of muscles innervated by cervical cord 5-6 (C5-C6) and cervical cord 8- thoracic cord 1 (C8-T1) in upper limb flexion synergy after stroke. Methods: Surface electromyography (sEMG) signals were collected during elbow flexion in stroke patients and healthy controls. The study compared normalized activation of two pairs of muscles that could cause similar joint movement but which dominated different spinal cord segments (clavicular part of the pectoralis major, PC vs. Sternocostal part of the pectoralis major, PS; Flexor carpi radialis, FCR vs. Flexor carpi ulnaris, FCU). In each muscle pair, one muscle was innervated by the same spinal cord segment (C5-C6), dominating the elbow flexion and the other was not. The comparison of the activation of the same muscle between patients and healthy controls was undertaken after standardization based on the activation of the biceps brachii in elbow flexion. Results: There was no difference between the PC and PS's normalized activation in healthy controls while the PC's normalized activation was higher than PS in stroke patients during elbow flexion. Similarly, there was no significant difference in normalized activation between FCR and FCU in healthy controls, and the same is true for stroke patients. However, the standardized activation of both FCR and FCU in stroke patients was significantly lower than that in healthy controls. Conclusion: After stroke, the activation of the distal muscles of the upper limb decreased significantly regardless of the difference of spinal cord segments; while the activation of the proximal muscles innervated by the same spinal cord segment (C5-C6) dominating the elbow flexion showed higher activation during flexion synergy. The difference in muscle activation based on spinal cord segments may be the reason for the stereotyped joint movement of upper limb flexion synergy.

Full Versus Trophic Feeds in Critically Ill Adults with High and Low Nutritional Risk Scores: A Randomized Controlled Trial.

Although energy intake might be associated with clinical outcomes in critically ill patients, it remains unclear whether full or trophic feeding is suitable for critically ill patients with high or low nutrition risk. We conducted a prospective study to determine which feeding energy intakes were associated with clinical outcomes in critically ill patients with high or low nutrition risk. This was an investigator-initiated, single center, single blind, randomized controlled trial. Critically ill patients were allocated to either high or low nutrition risk based on their Nutrition Risk in the Critically Ill score, and then randomized to receive either the full or the trophic feeding. The feeding procedure was administered for six days. No significant differences were observed in in-hospital, 14-day and 28-day mortalities, the length of ventilator dependency, or ICU and hospital stay among the four groups. There were no associations between energy and protein intakes and in-hospital, 14-day and 28-day mortalities in any of the four groups. However, protein intake was positively associated with the length of hospital stay and ventilator dependency in patients with low nutrition risk receiving trophic feeding. Full or trophic feeding in critically ill patients showed no associations with clinical outcomes, regardless of nutrition risk.

Comparison of Feeding Efficiency and Hospital Mortality between Small Bowel and Nasogastric Tube Feeding in Critically Ill Patients at High Nutritional Risk.

Nasogastric tube enteral nutrition (NGEN) should be initiated within 48 h for patients at high nutritional risk. However, whether small bowel enteral nutrition (SBEN) should be routinely used instead of NGEN to improve hospital mortality remains unclear. We retrospectively analyzed 113 critically ill patients with modified Nutrition Risk in Critically Ill (mNUTRIC) score ≥ 5 and feeding volume < 750 mL/day in the first week of their stay in the intensive care unit (ICU). Age, sex, mNUTRIC score, and Acute Physiology and Chronic Health Evaluation II (APACHE II) score were matched in the SBEN (n = 48) and NGEN (n = 65) groups. Through a univariate analysis, factors associated with hospital mortality were SBEN group (hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.31-1.00), Simplified Organ Failure Assessment (SOFA) score on day 7 (HR, 1.12; 95% CI, 1.03-1.22), and energy intake achievement rate < 65% (HR, 2.53; 95% CI, 1.25-5.11). A multivariate analysis indicated that energy intake achievement rate < 65% on the third follow-up day (HR, 2.29; 95% CI, 1.12-4.69) was the only factor independently associated with mortality. We suggest initiation of SBEN on the seventh ICU day before parenteral nutrition initiation for critically ill patients at high nutrition risk.

Optimal Time and Target for Evaluating Energy Delivery after Adjuvant Feeding with Small Bowel Enteral Nutrition in Critically Ill Patients at High Nutrition Risk.

Small bowel enteral nutrition (SBEN) may improve nutrient delivery to critically ill patients intolerant of gastric enteral nutrition. However, the optimal time and target for evaluating SBEN efficacy are unknown. This retrospective cohort study investigates these parameters in 55 critically ill patients at high nutrition risk (modified NUTRIC score ≥ 5). Daily actual energy intake was recorded from 3 days before SBEN initiation until 7 days thereafter. The energy achievement rate (%) was calculated as follows: (actual energy intake/estimated energy requirement) × 100. The optimal time was determined from the day on which energy achievement rate reached >60% post-SBEN. Assessment results were as follows: median APACHE II score, 27; SOFA score, 10.0; modified NUTRIC score, 7; and median time point of SBEN initiation, ICU day 8. The feeding volume, energy and protein intake, and achievement rate (%) of energy and protein intake increased significantly after SBEN (p < 0.001). An energy achievement rate less than 65% 3 days after SBEN was significantly associated with increased mortality after adjusting for confounding factors (odds ratio, 4.97; 95% confidence interval, 1.44⁻17.07). SBEN improves energy delivery in critically ill patients who are still at high nutrition risk after 1 week of stomach enteral nutrition.

Mechanistic Insight into Photocatalytic Pathways of MIL-100(Fe)/TiO2 Composites.

The integration of metal-organic frameworks (MOFs) with semiconductors has attracted mounting attention for photocatalytic applications. However, more efforts are needed to unravel the interface structure in MOF/semiconductor composites and its role in charge transfer. Herein, a MIL-100(Fe)/TiO2 composite was synthesized as a prototypical photocatalyst and studied systematically to explore the interface structure and unravel the charge transfer pathways during the photocatalytic processes. The composite was fabricated by growing MIL-100(Fe) crystals on TiO2 using surface-coated FeOOH as the precursor. The as-prepared MIL-100(Fe)/TiO2 exhibited significantly improved photocatalytic performance over pristine TiO2, which was mainly because of the enhanced charge separation as confirmed by transient absorption spectroscopy analysis. This enhancement partially arose from the special chemical structure at the interface, where the Fe-O-Ti bond was formed. As verified by the density functional theory calculation, this distinct structure would create defect energy levels adjacent to the valence band maximum of TiO2. During the photocatalytic processes, the defect energy levels serve as sinks to capture excited charge carriers and retard the recombination, which subsequently leads to the increased charge density and promoted photocatalytic efficiency. Meanwhile, the intimate interactions between MIL-100(Fe) and TiO2 would also help to improve the charge separation by transferring photo-induced holes through the ligands to Fe-O clusters. These findings would advance the fundamental understanding of the interface structure and the charge transfer pathways in MOF/semiconductor composite photocatalysts.

TRUSS inhibition protects against high fat diet (HFD)-stimulated brain injury by alleviation of inflammatory response.

High fat diet (HFD)-induced obesity is associated with insulin resistance (IR) and other chronic, diet associated illnesses, including neuroinflammation and brain injury. However, the involvement of inflammatory response in HFD-elicited central nerve injury has yet to be fully determined. Recent studies have indicated that tumor necrosis factor receptor-associated ubiquitous scaffolding and signaling protein (TRUSS), also known as TRPC4AP, plays an essential role in regulating inflammation via the meditation of NF-κB signaling. In the present study, we attempted to explore the effects of TRUSS on HFD-induced brain injury in the wild type mice (TRUSS+/+) or TRUSS-knockout mice (TRUSS-/-). The results suggested that TRUSS deletion attenuated HFD-induced cognitive impairments in mice. HFD-elicited metabolic disorders were also highly improved by the loss of TRUSS, as evidenced by the reduced serum glucose and insulin levels, as well as the lipid deposition in liver tissues. In addition, HFD-triggered brain injury was markedly alleviated by the TRUSS ablation, as proved by the reduction of GFAP and Iba1 expressions in hippocampus and hypothalamus. Moreover, TRUSS-/- mice exhibited a significant decrease in the expression of pro-inflammatory cytokines, accompanied with the inactivation of IKKα/IκBα/NF-κB pathway. At the same time, HFD-induced dyslipidemia was also alleviated by the loss of TRUSS. The in vitro study verified the protective effects of TRUSS-suppression against HFD-induced central nerve injury and hepatic steatosis by restraining the inflammatory response. In summary, our data indicated that TRUSS participated in metabolic syndrome-induced brain injury and pointed to the repression of TRUSS as a promising strategy for cognitive deficits therapy.

Pressure-regulated synthesis of Cu(TPA)·(DMF) in microdroplets for selective CO2 adsorption.

The synthesis of metal-organic frameworks (MOFs) by using traditional wet-chemistry methods generally requires very long durations and still suffers from non-uniform heat and mass transfer within the bulk precursor solutions. Towards addressing these issues, a microdroplet-based spray method has been developed. In a typical spray process, an MOF's precursor solution is first atomized into microdroplets. These droplets serve as microreactors to ensure homogeneous mixing, fast evaporation, and rapid nucleation and crystal growth to form MOF particles. However, the fundamental MOF formation mechanisms by using this strategy have not been fully understood. In this work, the role of the operating pressure in the synthesis of a representative MOF (i.e., Cu(TPA)·(DMF); TPA: terephthalic acid, DMF: dimethylformamide) was systematically investigated. Detailed characterization showed that the pressure variations significantly affected both the morphologies and crystalline structures of Cu(TPA)·(DMF). Numerical simulations revealed that the morphology changes are mainly attributed to the variations in supersaturation ratios, which are caused by different microdroplet evaporation rates due to the regulation of operating pressure, while the crystalline structure variations are closely related to the dissociation of DMF molecules at lower operating pressures. Besides, the dissociation of DMF molecules decreased the surface area of the MOF crystals, but gave rise to massive coordinatively unsaturated metal sites, which greatly enhanced the interaction of CO2 with the MOF crystal and thus led to improved CO2 adsorption capacity and selectivity. The outcome of this work would contribute to the fundamental understanding of MOF synthesis using the microdroplet-based spray method.

Simultaneous Detection and Removal of Formaldehyde at Room Temperature: Janus Au@ZnO@ZIF-8 Nanoparticles.

The detection and removal of volatile organic compounds (VOCs) are of great importance to reduce the risk of indoor air quality concerns. This study reports the rational synthesis of a dual-functional Janus nanostructure and its feasibility for simultaneous detection and removal of VOCs. The Janus nanostructure was synthesized via an anisotropic growth method, composed of plasmonic nanoparticles, semiconductors, and metal organic frameworks (e.g., Au@ZnO@ZIF-8). It exhibits excellent selective detection to formaldehyde (HCHO, as a representative VOC) at room temperature over a wide range of concentrations (from 0.25 to 100 ppm), even in the presence of water and toluene molecules as interferences. In addition, HCHO was also found to be partially oxidized into non-toxic formic acid simultaneously with detection. The mechanism underlying this technology was unraveled by both experimental measurements and theoretical calculations: ZnO maintains the conductivity, while ZIF-8 improves the selective gas adsorption; the plasmonic effect of Au nanorods enhances the visible-light-driven photocatalysis of ZnO at room temperature.

Warfarin and the Risk of Death, Stroke, and Major Bleeding in Patients With Atrial Fibrillation Receiving Hemodialysis: A Systematic Review and Meta-Analysis.

Background: Up to date, the efficacy and safety of warfarin treatment in atrial fibrillation patients receiving hemodialysis remain controversial. So we performed this meta-analysis to try to offer recommendations regarding warfarin management in this population. Methods: We searched Pubmed, Embase, and Cochrane library and reviewed relevant reference lists from 1980 to March 2018. Studies were included if they described the risks of mortality, stroke, and bleeding events with or without warfarin in atrial fibrillation patients receiving hemodialysis. Results: Overall, the use of warfarin was not associated with mortality (OR = 0.95, 95%CI = 0.89-1.02), stroke (OR = 1.06, 95% CI = 0.87-1.30) and ischemic stroke (OR = 0.85, 95% CI = 0.68-1.05), but its use could increase the risks of hemorrhagic stroke (OR = 1.34, 95% CI = 1.13-1.59) and major bleeding (OR = 1.24, 95% CI = 1.14, 1.35). In subgroup analyses, when analyses were mainly restricted to atrial fibrillation patients who were undergoing hemodialysis and taking other anticoagulation agents, warfarin therapy didn't reduce the risks for mortality (OR = 0.98, 95% CI = 0.68-1.42) and ischemic stroke (OR = 1.03, 95% CI = 0.89-1.19), but significantly increased the risks of stroke (OR:1.14, 95% CI = 1.01-1.29) and bleeding events such as hemorrhagic stroke (OR = 1.42, 95% CI = 1.14-1.77) and major bleeding (OR = 1.24, 95% CI = 1.14-1.35). While in patients who didn't take other anticoagulation agents or aspirin, warfarin use was not associated with all-cause mortality (OR = 0.90, 95% CI = 0.78-1.04), or any stroke (OR = 1.00, 95% CI = 0.71-1.40). Its use was associated with significantly decreased risk of ischemic stroke (OR = 0.71, 95% CI = 0.60-0.85), but not associated with hemorrhagic stroke (OR = 1.45, 95% CI = 0.83-2.55). Besides, another subgroup analysis showed that warfarin therapy didn't exert a protective role in patients with normal serum lipid levels (OR = 1.04, 95% CI = 0.85-1.26), but seemed to decrease the risk of ischemic stroke in patients with hyperlipidemia (OR = 0.38, 95% CI = 0.11-1.29). Conclusion: Our results suggested that it was necessary to prescribe warfarin for the prevention of ischemic events in hemodialysis patients with atrial fibrillation, but if these patients were already prescribed with other anticoagulants for the treatment of other co-existing diseases, then warfarin was not recommended.

Iron Oxide Nanowire-Based Filter for Inactivation of Airborne Bacteria.

Heating, ventilation, and air conditioning (HVAC) systems are among the most common methods to improve indoor air quality. However, after long-term operation, the HVAC filter can result in a proliferation of bacteria, which may release into the filtered air subsequently. This issue can be addressed by designing antibacterial filters. In this study, we report an iron oxide nanowires-based filter fabricated from commercially available iron mesh through a thermal treatment. At optimal conditions, the filter demonstrated a log inactivation efficiency of > 7 within 10 seconds towards S. epidermidis (Gram-positive), a common bacterial species of indoor bioaerosol. 52 % of bioaerosol cells can be captured by a single filter, which can be further improved to 98.7 % by connecting five filters in-tandem. The capture and inactivation capacity of the reported filter did not degrade over long-term use. The inactivation of bacteria is attributed to the synergic effects of the hydroxyl radicals, electroporation, and Joule heating, which disrupted the cell wall and nucleoid of S. epidermidis, as verified by the model simulations, fluorescence microscopy, electron microscopy, and infrared spectroscopy. The relative humidity plays an important role in the inactivation process. The filter also exhibited a satisfactory inactivation efficiency towards E. coli (Gram-negative). The robust synthesis, low cost, and satisfactory inactivation performance towards both Gram-positive and Gram-negative bacteria make the filter demonstrated here suitable to be assembled into HVAC filters as an antibacterial layer for efficient control of indoor bioaerosols.

Iron Mesh-Based Metal Organic Framework Filter for Efficient Arsenic Removal.

Efficient oxidation from arsenite [As(III)] to arsenate [As(V)], which is less toxic and more readily to be adsorbed by adsorbents, is important for the remediation of arsenic pollution. In this paper, we report a metal organic framework (MIL-100(Fe)) filter to efficiently remove arsenic from synthetic groundwater. With commercially available iron mesh as a substrate, MIL-100(Fe) is implanted through an in situ growth method. MIL-100(Fe) is able to capture As(III) due to its microporous structure, superior surface area, and ample active sites for As adsorption. This approach increases the localized As concentration around the filter, where Fenton-like reactions are initiated by the Fe2+/Fe3+ sites within the MIL-100(Fe) framework to oxidize As(III) to As(V). The mechanism was confirmed by colorimetric detection of H2O2, fluorescence, and electron paramagnetic resonance detection of ·OH. With the aid of oxygen bubbling and Joule heating, the removal efficiency of As(III) can be further boosted. The MIL-100(Fe)-based filter also exhibits satisfactory structural stability and recyclability. Notably, the adsorption capacity of the filter can be regenerated satisfactorily. Our results demonstrate the potential of this filter for the efficient remediation of As contamination in groundwater.

Rapid Formation of Metal-Organic Frameworks (MOFs) Based Nanocomposites in Microdroplets and Their Applications for CO2 Photoreduction.

A copper-based metal-organic framework (MOF), [Cu3(TMA)2(H2O)3]n (also known as HKUST-1, where TMA stands for trimesic acid), and its TiO2 nanocomposites were directly synthesized in micrometer-sized droplets via a rapid aerosol route for the first time. The effects of synthesis temperature and precursor component ratio on the physicochemical properties of the materials were systematically investigated. Theoretical calculations on the mass and heat transfer within the microdroplets revealed that the fast solvent evaporation and high heat transfer rates are the major driving forces. The fast droplet shrinkage because of evaporation induces the drastic increase in the supersaturation ratio of the precursor, and subsequently promotes the rapid nucleation and crystal growth of the materials. The HKUST-1-based nanomaterials synthesized via the aerosol route demonstrated good crystallinity, large surface area, and great photostability, comparable with those fabricated by wet-chemistry methods. With TiO2 embedded in the HKUST-1 matrix, the surface area of the composite is largely maintained, which enables significant improvement in the CO2 photoreduction efficiency, as compared with pristine TiO2. In situ diffuse reflectance infrared Fourier transform spectroscopy analysis suggests that the performance enhancement was due to the stable and high-capacity reactant adsorption by HKUST-1. The current work shows great promise in the aerosol route's capability to address the mass and heat transfer issues of MOFs formation at the microscale level, and ability to synthesize a series of MOFs-based nanomaterials in a rapid and scalable manner for energy and environmental applications.

Numerical Investigation of Miniature Ejector Refrigeration System Embedded with a Capillary Pump Loop.

A miniature steam ejector refrigeration system embedded with a capillary pump loop can result in a compact design which can be used for electronics cooling. In this paper, computational fluid dynamics (CFD) is employed to investigate the effects of the area ratio of the ejector constant-area mixing section to the nozzle throat, the length of the constant-area section, and the nozzle exit position (NXP), on the performance of a miniature steam ejector. Results show that the performance of the miniature steam ejector is very sensitive to the area ratio of the constant-area mixing section to the nozzle. For the needs of practical application, the area ratio of the constant-area mixing section to the nozzle should be smaller than 16 when the temperature of the primary flow is 60 °C. The NXP plays an important role in the flow phenomena inside the miniature ejector. The critical back pressure is more sensitive to length of the constant-area mixing section than the entrainment ratio. Results of this investigation provided a good solution to the miniature steam ejector embedded with a capillary pump loop for electronics cooling application.

Biocompatibility of gold nanoparticles in retinal pigment epithelial cell line.

Gold nanoparticles (Au NPs) have been tested as targeted delivery agents because of their high chemical stability and surface plasmon properties. Here, we investigated the biocompatibility of Au spheres (5-, 10-, 20-, 30-, 50-. and 100-nm), cubes (50-nm), and rods (10×90nm) on a retinal pigment epithelial (ARPE-19) cell line. The lethal dose for killing 50% of the cells (LD50) was evaluated using an MTT (3-[4, 5 dimethyl-thiazoly-2-yl] 2-5 diphenyl tetrazolium bromide) assay. At and above LD50, based on mass concentrations, the confluent cell layer began to detach, as shown by real-time measurements of electric impedance. We found that the biocompatibility of spheres improved with increasing nanoparticle size. The Au rods were less biocompatible than 10-nm spheres. Confocal microscopy showed that cubic (50-nm) and spherical NPs (50- and 100-nm) neither had cytotoxic effects nor entered cells. Lethal doses for internalized spherical NPs, which were toxic, were recalculated based on surface area (LD50,A) concentrations. Indeed, when biocompatibility was expressed as the surface area concentration of NPs, the curve was independent of size. The LD50,A of Au nanospheres was 23cm2/ml. Our findings demonstrate that the sole modulation of the surface area would make it possible to use Au NPs for therapeutic purposes.