Economic development, intergenerational mobility, and health in South Korea.

A growing number of studies reported the association between social mobility and health. However, few studies investigated whether the association varies by age group. Drawing on the economic environment that facilitated social mobility in South Korea, we postulate each age group had a different extent of social mobility, which would vary with the extent of economic growth and affect the association between social mobility and health. We used data from KDI National Happiness Survey 2018 and measured perceived mobility using respondents' perceived social position and their parents' social position. We examined whether social mobility was associated with self-rated health and psychological well-being. The upwardly mobile individuals were more likely than the stable ones to report 'happy'. Such a positive association between upward mobility and happiness was consistently found when the sample was restricted to the ages 30-59 and 40-49. For self-rated health, the downwardly mobile individuals were less likely to report good health. However, no significant difference in self-rated health was found after the youngest and oldest age groups were excluded. We found that perceived social mobility was strongly associated with psychological well-being rather than self-rated health. Moreover, we found a stronger association between upward mobility and happiness among the aged 40-49, who had the largest proportion of upwardly mobile individuals and spent their adolescence during rapid economic growth. The findings underscore the importance of the economic and social context in which individuals perceive their social position and shape their well-being.

Simply structured polarization-independent high efficiency multilayer dielectric gratings.

A polarization-independent multilayer dielectric diffraction grating with a low aspect ratio and high diffraction efficiency was designed and fabricated. The diffraction grating designed with a grating density of 1200 lines/mm had an aspect ratio of 0.59, mean polarization-independent diffraction efficiency in the Littrow angle of ±2.5∘, and 1030-1080 nm wavelength range of 97.2%. The designed grating was fabricated using ion assisted deposition and reactive ion etching techniques. The mean polarization-independent diffraction efficiency of the fabricated grating was 96.1%, and its standard deviation was 0.68%. The fabricated diffraction grating was irradiated with a 1064 nm cw laser, with a power density of 30kW/cm2, for 1 min to measure the temperature change before and after the laser application. It was verified that the temperature variation of the diffraction grating without heat treatment was 8.8°C, and the temperature variation after heat treatment at 400°C decreased to 2.3°C.

A Novel Muscle Atrophy Mechanism: Myocyte Degeneration Due to Intracellular Iron Deprivation.

Muscle atrophy is defined as the progressive degeneration or shrinkage of myocytes and is triggered by factors such as aging, cancer, injury, inflammation, and immobilization. Considering the total amount of body iron stores and its crucial role in skeletal muscle, myocytes may have their own iron regulation mechanism. Although the detrimental effects of iron overload or iron deficiency on muscle function have been studied, the molecular mechanism of iron-dependent muscle atrophy has not been elucidated. Using human muscle tissues and in the mouse rotator cuff tear model, we confirmed an association between injury-induced iron depletion in myocytes and muscle atrophy. In differentiated C2C12 myotubes, the effects of iron deficiency on myocytes and the molecular mechanism of muscle atrophy by iron deficiency were evaluated. Our study revealed that the lower iron concentration in injured muscle was associated with the upregulation of ferroportin, an iron exporter that transports iron out of cells. Ferroportin expression was increased by hypoxia-inducible factor 1α (HIF1α), which is activated by muscle injury, and its expression is controlled by HIF1 inhibitor treatment. Iron deprivation caused myocyte loss and a marked depletion of mitochondrial membrane potential leading to muscle atrophy, together with increased levels of myostatin, the upstream regulator of atrogin1 and muscle RING-finger protein-1 (MuRF1). Myostatin expression under iron deficiency was mediated by an orphan nuclear receptor, dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome (DAX1).

Gravimetric analysis of stability of polymeric materials during exposure to chemical disinfectants at different temperatures.

The goal of this study was to evaluate the impact of thermal and chemical aging processes on high-density polyethylene (HDPE), low-density polyethylene (LDPE), unplasticized polyvinyl chloride (U-PVC), and high-impact polyvinyl chloride (Hi-PVC) pipes. The materials were exposed to 1-10 ppm chemical disinfectants [chlorine dioxide (ClO2) and hypochlorite (HOCl)] at 40-80 °C for 1200 h. The diffusion properties of the materials were systematically analyzed based on the change in their sorption characteristics and activation energies according to the Arrhenius model. Moreover, the structural changes were analyzed with scanning electron microscopy (SEM), Fourier transform infrared (FTIR) radiation, and thermogravimetric analysis (TGA). The results show that the materials have Fickian characteristics in the aging environment. Specifically, the water sorption rates of HDPE and LDPE increase first and then decrease after reaching saturation (Ms); those of U-PVC and Hi-PVC its increasing continuously with different rate. This behavior of materials was prominent for ClO2 at high temperature and disinfectant dose because of polymeric chains crosslinking and rearrangement, extraction of monomers, and stable compounds removal during aging under exposed conditions. The deleterious effects decreased the activation energies of the materials and increased the concentrations of carbonyl groups [CO] via the formation of ketones, aldehydes, and carboxylic acids. The decomposition temperature increased with the changes in the material morphology and elemental contents under the investigated conditions. Moreover, LDPE and Hi-PVC were more severely affected in the thermal aging process with 10 mg.L-1 ClO2 at 80 °C.

Degradation analysis of polymeric pipe materials used for water supply systems under various disinfectant conditions.

Addition of chlorine dioxide (ClO2) or sodium hypochlorite (NaOCl) as a disinfectant in municipal water distribution systems is a common practice to deactivate micropollutants, but their impact on the pipe material with long-term exposure has not been discussed in detail. In this study, accelerated aging experiments were conducted for evaluating the oxidation of high-density polyethylene (HDPE), low-density polyethylene (LDPE), unplasticized polyvinylidene chloride (UPVC), and high-impact polyvinylidene chloride (Hi-PVC) pipes. The pipes were immersed in deionized (DI) water, ClO2, and NaOCl (2 mg/L, 5 mg/L, and 10 mg/L doses) for 1200 h of aging at 40 °C. The variations in the pipes structural, thermal, and mechanical characteristics were systematically investigated by attenuated total reflectance-Fourier transform infrared radiation (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and a universal testing machine (UTM). The formation of carbonyl groups due to methylene groups (C-C/C-H) oxidation resulted in an increased carbonyl index (CI) of the material exposed to accelerated aging conditions. Moreover, the XPS and ATR-FTIR results elucidated that the oxidation patterns under the exposure conditions followed from ketone/aldehyde formation to carboxylate groups (carboxylic acid/ester). The pipes were more vulnerable to the ClO2 compared to the DI water and NaOCl solution exposure. The increase in crystallinity and the decrease in oxidation induction time (OIT) of the pipe materials confirmed that the loss of stabilizer and changes in the chain alignment resulted in chain secession, loss of ductility, and lower percent elongation at break. Furthermore, results also elucidated that oxidative stability of the HDPE/UPVC was greater than that of the LDPE/Hi-PVC under disinfectant exposure regardless of the concentration and duration.

The lymphocyte/monocyte ratio and red blood cell transfusion during radical retropubic prostatectomy.

PURPOSE: Despite improvements of strategy in radical retropubic prostatectomy, blood loss is still a major concern. The lymphocyte/monocyte (LM) ratio is a prognostic indicator for various diseases. We identified the risk factors, including the LM ratio, for red blood cell (RBC) transfusion during radical retropubic prostatectomy. METHODS: This retrospective study assessed patients who underwent radical retropubic prostatectomy between March 2009 and December 2020. To determine the risk factors for RBC transfusion, a multivariate logistic regression analysis was conducted. A receiver operating characteristic (ROC) curve analysis was also performed. Postoperative outcomes, including acute kidney injury (AKI), hospitalization duration, and intensive care unit (ICU) admission, were also evaluated. RESULTS: Among 1302 patients, 158 patients (12.1%) received an intraoperative RBC transfusion. Multivariate logistic regression analysis demonstrated that the risk factors for RBC transfusion were the LM ratio, hemoglobin, 6% hydroxyethyl starch amount, and positive surgical margin. The area under the ROC curve of LM ratio was 0.706 (cut-off = 4.3). The LM ratio at ≤ 4.3 was significantly related to transfusion in multivariate-adjusted analysis (odds ratio = 4.598, P < 0.001). AKI and ICU admission were significantly higher, and the hospitalization duration was significantly longer in patients with RBC transfusion. CONCLUSIONS: The LM ratio was a risk factor for RBC transfusion in radical retropubic prostatectomy. The optimal cut-off value of the LM ratio to predict transfusion was 4.3. RBC transfusion was associated with poor postoperative outcomes. Therefore, our results suggest that the LM ratio provide useful information on RBC transfusion in radical retropubic prostatectomy.

A High-Fat Diet Activates the BAs-FXR Axis and Triggers Cancer-Associated Fibroblast Properties in the Colon.

BACKGROUND & AIMS: Dietary signals are known to modulate stemness and tumorigenicity of intestinal progenitors; however, the impact of a high-fat diet (HFD) on the intestinal stem cell (ISC) niche and its association with colorectal cancer remains unclear. Thus, we aimed to investigate how a HFD affects the ISC niche and its regulatory factors. METHODS: Mice were fed a purified diet (PD) or HFD for 2 months. The expression levels of ISC-related markers, ISC-supportive signals, and Wnt2b were assessed with real-time quantitative polymerase chain reaction, in situ hybridization, and immunofluorescence staining. RNA sequencing and metabolic function were analyzed in mesenchymal stromal cells (MSCs) from PD- and HFD-fed mice. Fecal microbiota were analyzed by 16s rRNA sequencing. Bile salt hydrolase activity and bile acid (BA) levels were measured. RESULTS: We found that expression of CD44 and Wnt signal-related genes was higher in the colonic crypts of HFD-fed mice than in those fed a PD. Within the ISC niche, MSCs were expanded and secreted predominant levels of Wnt2b in the colon of HFD-fed mice. Of note, increased energy metabolism and cancer-associated fibroblast (CAF)-like properties were found in the colonic MSCs of HFD-fed mice. Moreover, colonic MSCs from HFD-fed mice promoted the growth of tumorigenic properties and accelerated the expression of cancer stem cell (CSC)-related markers in colon organoids. In particular, production of primary and secondary BAs was increased through the expansion of bile salt hydrolase-encoding bacteria in HFD-fed mice. Most importantly, BAs-FXR interaction stimulated Wnt2b production in colonic CAF-like MSCs. CONCLUSIONS: HFD-induced colonic CAF-like MSCs play an indispensable role in balancing the properties of CSCs through activation of the BAs-FXR axis.

Differential regulation of the water channel protein aquaporins in chondrocytes of human knee articular cartilage by aging.

Knee cartilage is in an aqueous environment filled with synovial fluid consisting of water, various nutrients, and ions to maintain chondrocyte homeostasis. Aquaporins (AQPs) are water channel proteins that play an important role in water exchange in cells, and AQP1, -3, and -4 are known to be expressed predominantly in cartilage. We evaluated the changes in AQP expression in chondrocytes from human knee articular cartilage in patients of different ages and identified the key factor(s) that mediate age-induced alteration in AQP expression. The mRNA and protein expression of AQP1, -3 and -4 were significantly decreased in fibrocartilage compared to hyaline cartilage and in articular cartilage from older osteoarthritis patients compared to that from young patients. Gene and protein expression of AQP1, -3 and -4 were altered during the chondrogenic differentiation of C3H10T1/2 cells. The causative factors for age-associated decrease in AQP included H2O2, TNFα, and HMGB1 for AQP1, -3, and -4, respectively. In particular, the protective effect of AQP4 reduction following HMGB1 neutralization was noteworthy. The identification of other potent molecules that regulate AQP expression represents a promising therapeutic approach to suppress cartilage degeneration during aging.

Microbiota-derived lactate promotes hematopoiesis and erythropoiesis by inducing stem cell factor production from leptin receptor+ niche cells.

Although functional interplay between intestinal microbiota and distant sites beyond the gut has been identified, the influence of microbiota-derived metabolites on hematopoietic stem cells (HSCs) remains unclear. This study investigated the role of microbiota-derived lactate in hematopoiesis using mice deficient in G-protein-coupled receptor (Gpr) 81 (Gpr81-/-), an established lactate receptor. We detected significant depletion of total HSCs in the bone marrow (BM) of Gpr81-/- mice compared with heterogenic (Gpr81+/-) mice in a steady state. Notably, the expression levels of stem cell factor (SCF), which is required for the proliferation of HSCs, decreased significantly in leptin receptor-expressing (LepR+) mesenchymal stromal cells (MSCs) around the sinusoidal vessels of the BM from Gpr81-/- mice compared with Gpr81+/- mice. Hematopoietic recovery and activation of BM niche cells after irradiation or busulfan treatment also required Gpr81 signals. Oral administration of lactic acid-producing bacteria (LAB) activated SCF secretion from LepR+ BM MSCs and subsequently accelerated hematopoiesis and erythropoiesis. Most importantly, LAB feeding accelerated the self-renewal of HSCs in germ-free mice. These results suggest that microbiota-derived lactate stimulates SCF secretion by LepR+ BM MSCs and subsequently activates hematopoiesis and erythropoiesis in a Gpr81-dependent manner.

Diaphragm Thickening Fraction as a Prognostic Imaging Marker for Postoperative Pulmonary Complications in Robot-Assisted Laparoscopic Prostatectomy Requiring the Trendelenburg Position and Pneumoperitoneum.

BACKGROUND: Robot-assisted laparoscopic prostatectomy (RALP) frequently entails postoperative pulmonary complications (PPCs) due to the Trendelenburg position and pneumoperitoneum. Diaphragm thickening fraction (TF) as an imaging marker can offer the advantage of predicting respiratory outcomes. Therefore, we evaluated the effect of diaphragm TF on the occurrence of PPCs in RALP. METHODS: We measured the preoperative thickness of the diaphragm at peak inspiration (T pi) and end expiration (T ee) using ultrasonography. Diaphragm TF was calculated as TF = (T pi-T ee)/T ee. A receiver operating characteristic (ROC) curve analysis of TF was performed. After dividing patients into two groups according to the optimal TF cut-off value, we compared the occurrence of PPCs between the groups. The predictivity of diaphragm TF for the occurrence of PPCs was evaluated. RESULTS: Of 145 patients, 40 patients (27.6%) developed PPCs. Patients with PPCs had a significantly lower TF than those without PPCs (0.31 ± 0.09 vs. 0.39 ± 0.11, P < 0.001). In the ROC curve analysis, the optimal TF cut-off value was 0.28. The patients were divided into TF ≥ 0.28 group (n = 114) and TF < 0.28 group (n = 31). The incidence of PPCs was significantly higher in the TF < 0.28 group than in the TF ≥ 0.28 group (51.6% vs. 21.1%, P = 0.001). Diaphragm TF < 0.28 was associated with a higher incidence of PPCs than diaphragm TF ≥ 0.28 (odds ratio = 4.534, 95% confidence interval [1.763-11.658], P = 0.002). CONCLUSION: Preoperative diaphragm TF < 0.28 was associated with an increased incidence of PPCs, suggesting that diaphragm TF as a prognostic imaging marker provides useful information on PPCs in RALP requiring the Trendelenburg position and pneumoperitoneum. Trial Registry Number. This trial is registered with KCT0005028.

Adjuvant administration of hypertonic saline in lumbar epidural intervention may be associated with successful response in patients with probable neuropathic radicular pain Screened by Douleur Neuropathique 4.

Background: Chronic lumbar radicular pain often accompanies neuropathic pain. The treatment may follow a screening for probable neuropathic pain rather than the definitive diagnosis, which is often difficult in daily practice. However, interventional management may have limited effects on symptoms in patients with neuropathic radicular pain refractory to conservative treatments. The purpose of this study is to evaluate the factors associated with successful responses after lumbar epidural intervention in patients with chronic lumbar neuropathic radicular pain determined by Douleur Neuropathique 4 (DN4). Methods: We retrospectively reviewed 221 chronic lumbar radicular pain patients using a DN4 questionnaire prior to the epidural interventional procedure. The patients were divided into two groups according to the DN4 questionnaire: <4-point DN4 and ≥4 DN4. The numerical rating scale (NRS) for pain intensity, changes in physical functional status, and the use of pain medication were obtained before and 1 month after the procedure. Successful responder was defined based on robust combination of outcome parameters. The factors associated with successful response were analyzed using univariate and multivariate regression. Results: We found 170 (76.9%) patients with DN4 <4 and 51 (23.1%) with a score ≥4. Among the total 221 patients, 129 (58.4%) were successful responders and 92 (41.6%) were non-responders regardless of DN4 score. We observed a significantly lower proportion of successful responders among patients with a DN4 score ≥4 (22, 43.1%) than patients with a score <4 (107, 62.9%) (P=0.012). After adjusting in multivariate regression analysis, the DN4 score was independently associated with response after lumbar epidural intervention (odds ratio [OR]=0.838; 95% confidence interval [CI]=0.718-0.978; P=0.025). In subgroup logistic regression analysis according to the DN4 score, adjuvant administration of hypertonic saline during epidural interventions in patients with a DN4 score ≥4 (OR=3.71; CI=1.142-12.457; P=0.029) was associated with the success of the lumbar epidural procedure at 1 month. Conclusion: The adjuvant use of hypertonic saline in lumbar epidural interventions may be effective at least 1 month after the intervention in patients with probable neuropathic lumbar radicular pain ≥4 using the DN4.

Mucin degrader Akkermansia muciniphila accelerates intestinal stem cell-mediated epithelial development.

Mucin-degrading bacteria are densely populated in the intestinal epithelium; however, their interaction with intestinal stem cells (ISCs) and their progeny have not been elucidated. To determine whether mucin-degrading bacteria play a role in gut homeostasis, mice were treated with Akkermansia muciniphila, a specialized species that degrades mucin. Administration of A. muciniphila for 4 weeks accelerated the proliferation of Lgr5+ ISCs and promoted the differentiation of Paneth cells and goblet cells in the small intestine (SI). We found similar effects of A. muciniphila in the colon. The levels of acetic and propionic acids were higher in the cecal contents of A. muciniphila-treated mice than in PBS-treated mice. SI organoids treated with cecal contents obtained from A. muciniphila-treated mice were larger and could be diminished by treatment with G protein-coupled receptor (Gpr) 41/43 antagonists. Pre-treatment of mice with A. muciniphila reduced gut damage caused by radiation and methotrexate. Further, a novel isotype of the A. muciniphila strain was isolated from heathy human feces that showed enhanced function in intestinal epithelial regeneration. These findings suggest that mucin-degrading bacteria (e.g., A. muciniphila) may play a crucial role in promoting ISC-mediated epithelial development and contribute to intestinal homeostasis maintenance.

Sugammadex versus neostigmine on postoperative pulmonary complications after robot-assisted laparoscopic prostatectomy: a propensity score-matched analysis.

PURPOSE: Robot-assisted laparoscopic prostatectomy (RALP) requires particular surgical conditions, such as carbon dioxide pneumoperitoneum and steep Trendelenburg positioning, which may have adverse effects on the respiratory system. The effect of sugammadex on postoperative pulmonary complications (PPCs) is controversial. Therefore, we evaluated the incidence of PPCs according to the type of neuromuscular blockade reversal agents in RALP. METHODS: We retrospectively analyzed RALP patients. We compared the incidence of PPCs between patients receiving neostigmine (neostigmine group) and those receiving sugammadex (sugammadex group) as a neuromuscular blockade reversal agent. Propensity score-matched analysis was performed. Other postoperative outcomes, such as duration of hospital stays, major adverse cardiac events during hospital stays, and death during hospital stays, were also compared between the two groups. RESULTS: The incidence of PPCs was 28.9% (137/474) in RALP. The incidence of PPCs was significantly lower in the sugammadex group than in the neostigmine group (18.6% [44/237] vs. 39.2% [93/237], p < 0.001). The incidence of atelectasis was significantly lower in the sugammadex group than in the neostigmine group (18.6% vs. 39.2%, p < 0.001). The incidence of pneumonia was not significantly different between the sugammadex and neostigmine groups after RALP (0.0% vs. 0.4%, p > 0.999). Besides these, other postoperative outcomes were not significantly different between the two groups. CONCLUSIONS: The incidence of PPCs after RALP was significantly lower in patients receiving sugammadex than in those receiving neostigmine. These results can provide useful information on the appropriate selection of neuromuscular blockade reversal agents in RALP.

Relationship between fatty infiltration and gene expression in patients with medium rotator cuff tear.

BACKGROUND: Fatty infiltration (FI) is a key prognostic factor that affects outcomes after rotator cuff repair and is radiologically evaluated using the Goutallier classification. The purpose of this study was to assess alterations in gene and protein expression according to the Goutallier classification in the supraspinatus muscle and any relationships among various gene expression profiles. METHODS: Twenty-four samples of the supraspinatus muscle from 12 patients with a high FI grade (grade 3 or 4) and 12 patients with a low FI grade (grade 1 or 2) with medium-sized tears were acquired during arthroscopic surgery. Alterations in the expression of genes and proteins associated with adipogenesis, fibrosis, inflammation, and muscle atrophy were compared between the high- and low-FI groups using reverse-transcription quantitative polymerase chain reaction, Western blotting, and immunohistochemistry. RESULTS: mRNA expression of not only the adipogenic genes (peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α; P < .001 and P = .020) but also the fibrosis-related gene (α-smooth muscle actin; P < .001), inflammation-related genes (interleukin [IL]-1ß and tumor necrosis factor α; P = .041 and P = .039), and muscle atrophy-related genes (atrogin 1 and myostatin; P = .006 and P < .001) was higher in the high-FI group compared with that in the low-FI group. In addition, adipogenic gene expression was significantly correlated with the expression of other categories of genes (all P < .05, except atrogin 1). A correlation of gene and protein expression was observed for IL-1ß (P = .027) and myostatin (P = .029). CONCLUSIONS: The radiologic grading of FI was associated with the expression of various genes, including adipogenic, fibrotic, inflammatory, and atrophy-related genes, and these genes were closely correlated with each other in terms of expression. This information could be helpful in patient counseling.

Risk factors and outcomes of myocardial injury after non-cardiac surgery in high-risk patients who underwent radical cystectomy.

Radical cystectomy is considered the standard treatment for patients with muscle-invasive bladder tumors and has high postoperative complication rates among urological surgeries. High-risk patients, defined as those ≥45 years of age with history of coronary artery disease, stroke, or peripheral artery disease or those ≥65 years of age, can have a higher incidence of cardiac complications. Therefore, we evaluated the incidence, risk factors, and outcomes of myocardial injury after non-cardiac surgery (MINS) in high-risk patients who underwent radical cystectomy.This retrospective observational study analyzed 248 high-risk patients who underwent radical cystectomy. MINS was defined as serum troponin I concentration ≥0.04 mg/L within postoperative 3 days. The risk factors for MINS were evaluated by multivariate logistic regression analysis. Postoperative outcomes were evaluated. The 1-year survival after radical cystectomy was also compared between patients who developed MINS (MINS group) and those who did not (non-MINS group) by Kaplan-Meier analysis.MINS occurred in 35 patients (14.1%). Multivariate logistic regression analysis showed that early diastolic transmitral filling velocity (E)/early diastolic septal mitral annular velocity (E') ratio (odds ratio = 1.102, 95% confidence interval [1.009-1.203], P = .031) and large volume blood transfusion (odds ratio = 2.745, 95% confidence interval [1.131-6.664], P = .026) were significantly associated with MINS in high-risk patients who underwent radical cystectomy. Major adverse cardiac events and 1-year mortality were significantly higher in the MINS group than in the non-MINS group (17.1% vs 6.1%, P = .035; 28.6% vs 12.7%, P = .021, respectively). Kaplan-Meier analysis showed significantly lower 1-year survival in the MINS group than in the non-MINS group (P = .010).MINS occurred in 14.1% of patients. High E/E' ratio and large volume blood transfusion were risk factors for MINS in high-risk patients who underwent radical cystectomy. Postoperative major adverse cardiac events and 1-year mortality were significantly higher in the MINS group than in the non-MINS group. Preoperative evaluation of risk factors for MINS may provide useful information to detect cardiovascular complications after radical cystectomy in high-risk patients.

Optimization of preoxidation to reduce scaling during cleaning-in-place of membrane treatment.

This study investigated the potential for reducing scaling during chemical cleaning of polyvinylidene fluoride membranes by optimizing preoxidation dose and pH. Membranes were fouled by a solution containing inorganic foulants (aluminum, iron, and manganese), humic acid, and kaolin at a Ca+2 strength of 0.5 mM and varying the preoxidation dose. Energy-dispersive spectroscopy was used to verify the presence of inorganic foulants after cleaning. Fourier-transform infrared spectroscopy revealed changes in CCl and C-F functional groups, with bond vibrations at 542 cm-1 and 1199 cm-1, respectively. Minimum irreversible fouling of 5.4% and maximum flux recovery of 88.8% of the initial value were associated with a preoxidation dose of 1.5 mg/L and pH 8.5. A decrease in amount of aluminum from 5.79 ± 0.021 mg to 3.85 ± 0.054 mg in the presence of humic acid with a removal efficiency greater than 60% was due to alteration of the feed solution, as revealed by mass-balance analysis. Membrane characterization and fouling reversibility analysis confirmed that preoxidation of the feed solution produced less scaling during chemical cleaning. The cake layer fouling contribution was determined by fitting results of Hermia's fouling model analysis, with 1.34-1.85 times lower total fouling indices and 3-5.5 times lower chemically irreversible fouling indices at pH 8.5 and a preoxidation dose of 1.5 mg/L.

Atrogin1-induced loss of aquaporin 4 in myocytes leads to skeletal muscle atrophy.

The water channel aquaporin 4 (AQP4) regulates the flux of water across the cell membrane, maintaining cellular homeostasis. Since AQP4 is enriched in the sarcolemma of skeletal muscle, a functional defect in AQP4 may cause skeletal muscle dysfunction. To investigate a novel mechanism underlying skeletal muscle atrophy, we examined AQP4 expression and its regulation in muscle using the rotator cuff tear (RCT) model. Human and mouse AQP4 expression was significantly decreased in atrophied muscle resulting from RCT. The size and the number of myotubes were reduced following AQP4 knockdown. Atrogin 1-mediated ubiquitination of AQP4 was verified with an ubiquitination assay after immunoprecipitation of AQP4 with an anti-AQP4 antibody. In this study, we identified high mobility group box 1 (HMGB1) as a potent upstream regulator of atrogin 1 expression. Atrogin 1 expression was increased by recombinant mouse HMGB1 protein, and the HMGB1-induced atrogin 1 expression was mediated via NF-κB signaling. Our study suggests that loss of AQP4 appears to be involved in myocyte shrinkage after RCT, and its degradation is mediated by atrogin 1-dependent ubiquitination. HMGB1, in its function as a signaling molecule upstream of the ubiquitin ligase atrogin 1, was found to be a novel regulator of muscle atrophy.

A comparison of variations in blocking mechanisms of membrane-fouling models for estimating flux during water treatment.

This study investigates five different fouling models and contributing factors in membrane-filtration blocking mechanisms in a constant-pressure mode. A polyvinylidene fluoride membrane was used to study the fouling effects of a complex mixture of foulants (a latex-bed suspension, soybean oil, and inorganics) on pristine and chemically cleaned membranes in the presence of humic acid. A significance ratio in linear regression results (p-value) was used to assess the contribution of fouling mechanism in each model. The results indicate that Hermia and Bowen's models correspond closely with the experiment results and confirms that complete blocking is dominant fouling model. We also verify that each developed model is dependent on its experimental conditions. Moreover, the role of complex mixtures, including inorganic foulants, in the fouling process needs to be modified as modified for ceramic membranes and natural organic matter removal in the Wiesner and Kilduff models, respectively.