Effects of methane to oxygen ratio on cell growth and polyhydroxybutyrate synthesis in high cell density cultivation of Methylocystis sp. MJC1.

Polyhydroxybutyrate (PHB) production through CH4 conversion by methanotrophs offers a solution for greenhouse gas emissions and plastic waste concerns. In this study, we aimed to achieve high cell density cultivation of Methylocystis sp. MJC1 for efficient PHB production. Cultivating MJC1 using CH4 and air (3:7, v/v) yielded a final cell density of 52.9 g/L with a 53.7% (28.4 g/L) PHB content after 210 h, showcasing PHB mass production potential. However, long-term cultivation led to a low volumetric productivity of 0.200 g/L/h. To address this, we conducted cultivation at various O2/CH4 ratios using O2 instead of air, which significantly improved the PHB productivity. Under high O2 conditions (O2/CH4 ratio of 1.5), biomass productivity increased 1.51-fold compared to that under low O2 conditions in the same time frame; however, PHB accumulation was delayed. Using an equal ratio of CH4 and O2 induced active cell growth and selective PHB production, achieving the highest PHB productivity (0.365 g/L/h) with a final cell density of 55.9 g/L and PHB content of 61.7% (34.5 g/L) in 162 h. This study highlighted the significance of the O2/CH4 ratio in CH4 conversion and PHB production by M. sp. MJC1.

High production of ectoine from methane in genetically engineered Methylomicrobium alcaliphilum 20Z by preventing ectoine degradation.

BACKGROUND: Methane is a greenhouse gas with a significant potential to contribute to global warming. The biological conversion of methane to ectoine using methanotrophs represents an environmentally and economically beneficial technology, combining the reduction of methane that would otherwise be combusted and released into the atmosphere with the production of value-added products. RESULTS: In this study, high ectoine production was achieved using genetically engineered Methylomicrobium alcaliphilum 20Z, a methanotrophic ectoine-producing bacterium, by knocking out doeA, which encodes a putative ectoine hydrolase, resulting in complete inhibition of ectoine degradation. Ectoine was confirmed to be degraded by doeA to N-α-acetyl-L-2,4-diaminobutyrate under nitrogen depletion conditions. Optimal copper and nitrogen concentrations enhanced biomass and ectoine production, respectively. Under optimal fed-batch fermentation conditions, ectoine production proportionate with biomass production was achieved, resulting in 1.0 g/L of ectoine with 16 g/L of biomass. Upon applying a hyperosmotic shock after high-cell-density culture, 1.5 g/L of ectoine was obtained without further cell growth from methane. CONCLUSIONS: This study suggests the optimization of a method for the high production of ectoine from methane by preventing ectoine degradation. To our knowledge, the final titer of ectoine obtained by M. alcaliphilum 20ZDP3 was the highest in the ectoine production from methane to date. This is the first study to propose ectoine production from methane applying high cell density culture by preventing ectoine degradation.

Predictors of Burden for First-Ever Stroke Survivor's Long-Term Caregivers: A Study of KOSCO.

Long-term changes in caregiver burden should be clarified considering that extended post-stroke disability can increase caregiver stress. We assessed long-term changes in caregiver burden severity and its predictors. This study was a retrospective analysis of the Korean Stroke Cohort for Functioning and Rehabilitation. Patients with an acute first-ever stroke were enrolled from August 2012 to May 2015. Data were collected at 6 months and 6 years after stroke onset. The caregiver burden was measured with a subjective caregiver burden questionnaire based on the Korean version of the Caregiver Burden Inventory. The caregivers' characteristics and patients' clinical and functional status were also examined at each follow-up. A high caregiver burden, which suggests a risk of burnout, was reported by 37.9% and 51.7% of caregivers at 6 months and 6 years post-stroke, respectively. Both the caregiver burden total score and proportion of caregivers at risk of burnout did not decrease between 6 months and 6 years. The patients' disability (OR = 11.60; 95% CI 1.58-85.08; p = 0.016), caregivers' self-rated stress (OR = 0.03; 95% CI 0.00-0.47; p = 0.013), and caregivers' quality of life (OR = 0.76; 95% CI 0.59-0.99; p = 0.042) were burden predictors at 6 months. At 6 years, only the patients' disability (OR = 5.88; 95% CI 2.19-15.82; p < 0.001) and caregivers' psychosocial stress (OR = 1.26; 95% CI 1.10-1.44; p = 0.001) showed significance. Nearly half of the caregivers were at risk of burnout, which lasted for 6 years after stroke onset. The patients' disability and caregivers' stress were burden predictors in both subacute and chronic phases of stroke. The findings suggest that consistent interventions, such as emotional support or counseling on stress relief strategies for caregivers of stroke survivors, may reduce caregiver burden. Further research is needed to establish specific strategies appropriate for Korean caregivers to alleviate their burden in caring for stroke patients.

Dissecting Alzheimer's Disease Risk in Asian American Elders: A Classification and Regression Tree Approach.

Background: Alzheimer's disease (AD) poses a growing public health challenge, particularly with an aging population. While extensive research has explored the relationships between AD, socio-demographic factors, and cardiovascular risk factors, a notable gap exists in understanding these connections within the Asian American elderly population. Objective: This study aims to address this gap by employing the Classification and Regression Tree (CART) approach to investigate the intricate interplay of socio-demographic variables, cardiovascular risk factors, sleep patterns, prior antidepressant use, and AD among Asian American elders. Methods: Data from the 2017 Uniform Data Set, provided by the National Alzheimer's Coordinating Center, were analyzed, focusing on a sample of Asian American elders (n = 4,343). The analysis utilized the Classification and Regression Tree (CART) approach. Results: CART analysis identified critical factors, including levels of independence, specific age thresholds (73.5 and 84.5 years), apnea, antidepressant use, and body mass index, as significantly associated with AD risk. Conclusions: These findings have far-reaching implications for future research, particularly in examining the roles of gender, cultural nuances, socio-demographic factors, and cardiovascular risk elements in AD within the Asian American elderly population. Such insights can inform tailored interventions, improved healthcare access, and culturally sensitive policies to address the complex challenges posed by AD in this community.

Research trends in ergonomics, industrial safety and health: semantic network and topic analyses.

We evaluated the research trends in ergonomics, industrial safety and health from the 1980s to the present. In the ergonomics area, keywords and abstracts from five journals were analyzed. For industrial safety and health, six journal databases were evaluated. A frequency analysis, a semantic network of keywords and a topic network of abstracts were conducted. The results of ergonomics showed that 'macro-ergonomics' and 'manual material handling' were the most popular topics, and 'ergonomic' and 'electromyography' were the most cited keywords. 'Posture' and 'biomechanics' were the most frequently used with high centrality. The results of industrial safety and health showed that 'job stress' and 'organizational safety' were the most popular topics, and 'occupational exposure' and 'occupational health' were the most cited keywords. 'Dust' and 'exposure' were frequently used with high centrality. The results would be helpful in understanding the trends of research efforts and foreseeing trends of future research.

Evaluation of ergonomic risks for work-related musculoskeletal disorders of nursing tasks in Korea.

Among all industrial accident-induced diseases, musculoskeletal disorders (MSDs) are most prominently observed among nurses. The physical load of everyday tasks involved in nursing work was assessed in this study using a developed risk index, whereby the physical burden was evaluated using the exposure duration and work intensity levels. This survey targeted nine small, medium and large-sized hospitals in South Korea and categorized representative nursing tasks into six groups. The subtasks within these six categories (evaluated as high risk) included changing a patient's posture and assisting with walkers or wheelchairs, transporting/handling drug carts, bathing patients, replacing bedding, traction therapy, cardiopulmonary resuscitation and artificial manual breathing unit, and computer work. The risk index ratio was significantly different by task type for each task. We demonstrated that the risk index developed in this study can be used to evaluate MSDs in hospitals.

Avian obligate brood parasitic lineages evolved variable complex polycrystalline structures to build tougher eggshells.

Avian brood parasites and their hosts display varied egg-puncture behaviors, exerting asymmetric co-evolutionary selection pressures on eggshells' breaking strength. We investigated eggshell structural and textural characteristics that may improve its mechanical performance. Parasitic eggshell calcified layers showed complex ultra- and microstructural patterns. However, stronger parasitic eggshells are not due to lower textural severity (characterized by lower preferred crystallographic orientation, larger local grain misorientation and smaller Kearns factor), but rather to grain boundary (GB) microstructure characteristics within the eggshell outermost layer (palisade layer, PL). Accordingly, the thicker the PL and the more complex the GB pathways are, the tougher the parasitic eggshells will be. These characteristics, which we can identify as a "GB Engineering" driven co-evolutionary process, further improve eggshell breaking strength in those parasitic species that suffer relatively high frequencies of egg-puncturing by congeneric or hosts. Overall, plain textural patterns are not suitable predictors for comparing mechanical performance of bioceramic materials.

A Cell-Penetrant Peptide Disrupting the Transcription Factor CP2c Complexes Induces Cancer-Specific Synthetic Lethality.

Despite advances in precision oncology, cancer remains a global public health issue. In this report, proof-of-principle evidence is presented that a cell-penetrable peptide (ACP52C) dissociates transcription factor CP2c complexes and induces apoptosis in most CP2c oncogene-addicted cancer cells through transcription activity-independent mechanisms. CP2cs dissociated from complexes directly interact with and degrade YY1, leading to apoptosis via the MDM2-p53 pathway. The liberated CP2cs also inhibit TDP2, causing intrinsic genome-wide DNA strand breaks and subsequent catastrophic DNA damage responses. These two mechanisms are independent of cancer driver mutations but are hindered by high MDM2 p60 expression. However, resistance to ACP52C mediated by MDM2 p60 can be sensitized by CASP2 inhibition. Additionally, derivatives of ACP52C conjugated with fatty acid alone or with a CASP2 inhibiting peptide show improved pharmacokinetics and reduced cancer burden, even in ACP52C-resistant cancers. This study enhances the understanding of ACP52C-induced cancer-specific apoptosis induction and supports the use of ACP52C in anticancer drug development.

Multi-class semantic segmentation of breast tissues from MRI images using U-Net based on Haar wavelet pooling.

MRI images used in breast cancer diagnosis are taken in a lying position and therefore are inappropriate for reconstructing the natural breast shape in a standing position. Some studies have proposed methods to present the breast shape in a standing position using an ordinary differential equation of the finite element method. However, it is difficult to obtain meaningful results because breast tissues have different elastic moduli. This study proposed a multi-class semantic segmentation method for breast tissues to reconstruct breast shapes using U-Net based on Haar wavelet pooling. First, a dataset was constructed by labeling the skin, fat, and fibro-glandular tissues and the background from MRI images taken in a lying position. Next, multi-class semantic segmentation was performed using U-Net based on Haar wavelet pooling to improve the segmentation accuracy for breast tissues. The U-Net effectively extracted breast tissue features while reducing image information loss in a subsampling stage using multiple sub-bands. In addition, the proposed network is robust to overfitting. The proposed network showed a mIOU of 87.48 for segmenting breast tissues. The proposed networks demonstrated high-accuracy segmentation for breast tissue with different elastic moduli to reconstruct the natural breast shape.

Polyhydroxybutyrate Production from Methane and Carbon Dioxide by a Syntrophic Consortium of Methanotrophs with Oxygenic Photogranules without an External Oxygen Supply.

Here, a syntrophic process was developed to produce polyhydroxy-ß-butyrate (PHB) from a gas stream containing CH4 and CO2 without an external oxygen supply using a combination of methanotrophs with the community of oxygenic photogranules (OPGs). The co-culture features of Methylomonas sp. DH-1 and Methylosinus trichosporium OB3b were evaluated under carbon-rich and carbon-lean conditions. The critical role of O2 in the syntrophy was confirmed through the sequencing of 16S rRNA gene fragments. Based on their carbon consumption rates and the adaptation to a poor environment, M. trichosporium OB3b with OPGs was selected for methane conversion and PHB production. Nitrogen limitation stimulated PHB accumulation in the methanotroph but hindered the growth of the syntrophic consortium. At 2.9 mM of the nitrogen source, 1.13 g/L of biomass and 83.0 mg/L of PHB could be obtained from simulated biogas. These results demonstrate that syntrophy has the potential to convert greenhouse gases into valuable products efficiently.

Mobile Kink Solitons in a Van der Waals Charge-Density-Wave Layer.

Kinks, point-like geometrical defects along dislocations, domain walls, and DNA, are stable and mobile, as solutions of a sine-Gordon wave equation. While they are widely investigated for crystal deformations and domain wall motions, electronic properties of individual kinks have received little attention. In this work, electronically and topologically distinct kinks are discovered along electronic domain walls in a correlated van der Waals insulator of 1T-TaS2 . Mobile kinks and antikinks are identified as trapped by pinning defects and imaged in scanning tunneling microscopy. Their atomic structures and in-gap electronic states are unveiled, which are mapped approximately into Su-Schrieffer-Heeger solitons. The twelvefold degeneracy of the domain walls in the present system guarantees an extraordinarily large number of distinct kinks and antikinks to emerge. Such large degeneracy together with the robust geometrical nature may be useful for handling multilevel information in van der Waals materials architectures.

Platelet to lymphocyte ratio is a risk factor for failure of non-operative treatment of colonic diverticulitis.

Non-operative treatment is the mainstay of colonic diverticulitis, but some patients require surgery due to non-operative treatment failure. This study aims to identify risk factors for the failure of non-operative treatment of colonic diverticulitis. From January 2011 to December 2020, we retrospectively reviewed 2362 patients with non-operative treatment for first-attack acute diverticulitis. Patients were categorized into non-operative treatment success or failure groups. Clinical characteristics and serum inflammatory markers were analyzed by multivariable logistic regression to determine risk factors for non-operative treatment failure of colonic diverticulitis. Overall, 2.2% (n = 50) of patients underwent delayed surgery within 30 days (median 4.0 [3.0; 8.0]) due to non-operative treatment failure. Multivariable logistic regression identified that platelet to lymphocyte ratio (odds ratio [OR], 4.2; 95% confidence interval [CI], 0.05-0.13; p < 0.001), diabetes mellitus (OR, 2.2; 95% CI, 0.01-0.09; p = 0.025), left-sided colonic diverticulitis (OR, 4.1; 95% CI, 0.04-0.13; p < 0.001), and modified Hinchey classification (OR, 6.2; 95% CI, 0.09-0.17; p < 0.001) were risk factors for non-operative treatment failure. Platelet to lymphocyte ratio (PLR) is a potential risk factor for the non-operative treatment failure of acute first-attack colonic diverticulitis. Therefore, patients with higher PLR during non-operative treatment should be monitored with special caution.

Activating transcription factor-2 supports the antioxidant capacity and ability of human mesenchymal stem cells to prevent asthmatic airway inflammation.

Glutathione (GSH), an abundant nonprotein thiol antioxidant, participates in several biological processes and determines the functionality of stem cells. A detailed understanding of the molecular network mediating GSH dynamics is still lacking. Here, we show that activating transcription factor-2 (ATF2), a cAMP-response element binding protein (CREB), plays a crucial role in maintaining the level and activity of GSH in human mesenchymal stem cells (MSCs) by crosstalking with nuclear factor erythroid-2 like-2 (NRF2), a well-known master regulator of cellular redox homeostasis. Priming with ascorbic acid 2-glucoside (AA2G), a stable vitamin C derivative, increased the expression and activity of ATF2 in MSCs derived from human embryonic stem cells and umbilical cord. Subsequently, activated ATF2 crosstalked with the CREB1-NRF2 pathway to preserve the GSH dynamics of MSCs through the induction of genes involved in GSH synthesis (GCLC and GCLM) and redox cycling (GSR and PRDX1). Accordingly, shRNA-mediated silencing of ATF2 significantly impaired the self-renewal, migratory, proangiogenic, and anti-inflammatory capacities of MSCs, and these defects were rescued by supplementation of the cells with GSH. In addition, silencing ATF2 attenuated the ability of MSCs to alleviate airway inflammatory responses in an ovalbumin-induced mouse model of allergic asthma. Consistently, activation of ATF2 by overexpression or the AA2G-based priming procedure enhanced the core functions of MSCs, improving the in vivo therapeutic efficacy of MSCs for treating asthma. Collectively, our findings suggest that ATF2 is a novel modulator of GSH dynamics that determines the core functionality and therapeutic potency of MSCs used to treat allergic asthma.

Use of Nucleating Agent NA11 in the Preparation of Polyvinylidene Fluoride Dual-Layer Hollow Fiber Membranes.

Polyvinylidene fluoride (PVDF) dual-layer hollow fiber membranes were simultaneously fabricated by thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) methods using a triple orifice spinneret (TOS) for water treatment application. The support layer was prepared from a TIPS dope solution, which was composed of PVDF, gamma-butyrolactone (GBL), and N-methyl-2-pyrrolidone (NMP). The coating layer was prepared from a NIPS dope solution, which was composed of PVDF, N,N-dimethylacetamide (DMAc), and polyvinylpyrrolidone (PVP). In order to improve the mechanical strength of the dual-layer hollow fiber, a nucleating agent, sodium 2,2'-methylene bis-(4,6-di-tert-butylphenyl) phosphate (NA11), was added to the TIPS dope solution. The performance of the membrane was evaluated by surface and cross-sectional morphology, water flux, mechanical strength, and thermal property. Our results demonstrate that NA11 improved the mechanical strength of the PVDF dual-layer hollow fiber membranes by up to 42%. In addition, the thickness of the coating layer affected the porosity of the membrane and mechanical performance to have high durability in enduring harsh processing conditions.

Bioupgrading of the aqueous phase of pyrolysis oil from lignocellulosic biomass: a platform for renewable chemicals and fuels from the whole fraction of biomass.

Pyrolysis, a thermal decomposition without oxygen, is a promising technology for transportable liquids from whole fractions of lignocellulosic biomass. However, due to the hydrophilic products of pyrolysis, the liquid oils have undesirable physicochemical characteristics, thus requiring an additional upgrading process. Biological upgrading methods could address the drawbacks of pyrolysis by utilizing various hydrophilic compounds as carbon sources under mild conditions with low carbon footprints. Versatile chemicals, such as lipids, ethanol, and organic acids, could be produced through microbial assimilation of anhydrous sugars, organic acids, aldehydes, and phenolics in the hydrophilic fractions. The presence of various toxic compounds and the complex composition of the aqueous phase are the main challenges. In this review, the potential of bioconversion routes for upgrading the aqueous phase of pyrolysis oil is investigated with critical challenges and perspectives.

Regulation of Genes Related to Cognition after tDCS in an Intermittent Hypoxic Brain Injury Rat Model.

Background: Hypoxic brain injury is a condition caused by restricted oxygen supply to the brain. Several studies have reported cognitive decline, particularly in spatial memory, after exposure to intermittent hypoxia (IH). However, the effect and mechanism of action of IH exposure on cognition have not been evaluated by analyzing gene expression after transcranial direct current stimulation (tDCS). Hence, the purpose of this study was to investigate the effects of tDCS on gene regulation and cognition in a rat model of IH-induced brain injury. Methods: Twenty-four 10-week-old male Sprague−Dawley rats were divided into two groups: IH exposed rats with no stimulation and IH-exposed rats that received tDCS. All rats were exposed to a hypoxic chamber containing 10% oxygen for twelve hours a day for five days. The stimulation group received tDCS at an intensity of 200 µA over the frontal bregma areas for 30 min each day for a week. As a behavior test, the escape latency on the Morris water maze (MWM) test was measured to assess spatial memory before and after stimulation. After seven days of stimulation, gene microarray analysis was conducted with a KEGG mapper tool. Results: Although there were no significant differences between the groups before and after stimulation, there was a significant effect of time and a significant time × group interaction on escape latency. In the microarray analysis, significant fold changes in 12 genes related to neurogenesis were found in the stimulation group after tDCS (p < 0.05, fold change > 2 times, the average of the normalized read count (RC) > 6 times). The highly upregulated genes in the stimulation group after tDCS were SOS, Raf, PI3K, Rac1, IRAK, and Bax. The highly downregulated genes in the stimulation group after tDCS were CHK, Crk, Rap1, p38, Ras, and NF-kB. Conclusion: In this study, we confirmed that SOS, Raf, PI3K, Rac1, IRAK, and Bax were upregulated and that CHK, Crk, Rap1, p38, Ras, and NF-kB were downregulated in a rat model of IH-induced brain injury after application of tDCS.

3D convolutional neural network for machining feature recognition with gradient-based visual explanations from 3D CAD models.

In the manufacturing industry, all things related to a product manufactured are generated and managed with a three-dimensional (3D) computer-aided design (CAD) system. CAD models created in a 3D CAD system are represented as geometric and topological information for exchange between different CAD systems. Although 3D CAD models are easy to use for product design, it is not suitable for direct use in manufacturing since information on machining features is absent. This study proposes a novel deep learning model to recognize machining features from a 3D CAD model and detect feature areas using gradient-weighted class activation mapping (Grad-CAM). To train the deep learning networks, we construct a dataset consisting of single and multi-feature. Our networks comprised of 12 layers classified the machining features with high accuracy of 98.81% on generated datasets. In addition, we estimated the area of the machining feature by applying Grad-CAM to the trained model. The deep learning model for machining feature recognition can be utilized in various fields such as 3D model simplification, computer-aided engineering, mechanical part retrieval, and assembly component identification.

Vitamin C Lowers Blood Pressure in Spontaneously Hypertensive Rats by Targeting Angiotensin-Converting Enzyme I Production in a Frequency-Dependent Manner.

The lowering blood pressure effect of vitamin C (VC) has been evaluated in various models. As VC has a fast degradation rate in the body after consumption, a study of the frequency-dependent manner of VC is essential for the sustained antihypertension effect of VC. In this study, we investigated the frequency and dose dependency of vitamin C (VC) on blood pressure reduction in spontaneously hypertensive rats (SHRs). Wistar-Kyoto rats (WKYs) and SHRs were orally administered tap water or VC (250, 500, 1000, and 2000 mg/60 kg/day). Blood pressures were measured using the tail-cuff method, and thoracic aortas, liver, and blood were harvested from sacrificed rats after 8 weeks to measure angiotensinogen, angiotensin-converting enzyme (ACE) I, endothelial nitric oxide synthase (eNOS), and total nitric oxide (NOx) concentration. VC decreased blood pressure from the fourth week with no significant differences between doses. The twice-a-day administration of VC decreased blood pressure from the second week, and the blood pressure in these groups was close to that of the WKY group in the eighth week. Treatment with once a day VC decreased ACE I production which was further significantly reduced in twice a day groups. Angiotensinogen and eNOS production were increased upon VC treatment but were not significant among groups. The NOx content was decreased by VC treatment. These results suggest that VC lowers blood pressure in SHRs by directly targeting ACE I production in a frequency-dependent manner and may improve endothelial function depending on the frequency of administration.

The CDK1/TFCP2L1/ID2 cascade offers a novel combination therapy strategy in a preclinical model of bladder cancer.

Aberrant activation of embryogenesis-related molecular programs in urothelial bladder cancer (BC) is associated with stemness features related to oncogenic dedifferentiation and tumor metastasis. Recently, we reported that overexpression of transcription factor CP2-like protein-1 (TFCP2L1) and its phosphorylation at Thr177 by cyclin-dependent kinase-1 (CDK1) play key roles in regulating bladder carcinogenesis. However, the clinical relevance and therapeutic potential of this novel CDK1-TFCP2L1 molecular network remain elusive. Here, we demonstrated that inhibitor of DNA binding-2 (ID2) functions as a crucial mediator by acting as a direct repressive target of TFCP2L1 to modulate the stemness features and survival of BC cells. Low ID2 and high CDK1 expression were significantly associated with unfavorable clinical characteristics. TFCP2L1 downregulated ID2 by directly binding to its promoter region. Consistent with these findings, ectopic expression of ID2 or treatment with apigenin, a chemical activator of ID2, triggered apoptosis and impaired the proliferation, suppressed the stemness features, and reduced the invasive capacity of BC cells. Combination treatment with the specific CDK1 inhibitor RO-3306 and apigenin significantly suppressed tumor growth in an orthotopic BC xenograft animal model. This study demonstrates the biological role and clinical utility of ID2 as a direct target of the CDK1-TFCP2L1 pathway for modulating the stemness features of BC cells.