Ni-Rich Layered Oxide Cathodes/Sulfide Electrolyte Interface in Solid-State Lithium Battery

Because of the high specific capacity and low cost, Ni-rich layered oxide (NRLO) cathodes are one of the most promising cathode candidates for the next high-energy-density lithium-ion batteries. However, they face structure and interface instability challenges, especially the battery safety risk caused by using an intrinsic flammable organic liquid electrolyte. In this regard, a solid electrolyte with high safety is of great significance to promote the development of energy storage. Among them, sulfide electrolytes are considered to be the most potential substitutes for liquid electrolytes because of their high ionic conductivity and good processing properties. Nevertheless, the interfacial incompatibility between the sulfide electrolyte and NRLO cathode is the critical challenge for high-performance sulfide all-solid-state lithium batteries (ASSLBs). In this review, we summarize the problems of the Ni-rich cathode/sulfide solid electrolyte interface and the strategies to improve the interface stability. On the basis of these insights, we highlight the scientific problems and technological challenges that need to be resolved urgently and propose several potential directions to further improve the interface stability. The objective of this study is to provide a comprehensive understanding and insightful recommendations for the enhancement of the sulfide ASSLBs with NRLO cathode.

A kinetic model reveals the critical gating motifs for donor-substrate loading into Actinobacillus pleuropneumoniae N-glycosyltransferase

Soluble N-glycosyltransferase from Actinobacillus pleuropneumoniae (ApNGT) catalyzes the glycosylation of asparagine residues, and represents one of the most encouraging biocatalysts for N-glycoprotein production. Since the sugar tolerance of ApNGT is restricted to limited monosaccharides (e.g., Glc, GlcN, Gal, Xyl, and Man), tremendous efforts are devoted to expanding the substrate scope of ApNGT via enzyme engineering. However, rational design of novel NGT variants suffers from an elusive understanding of the substrate-binding process from a dynamic point of view. Here, by employing extensive all-atom molecular dynamics (MD) simulations integrated with a kinetic model, we reveal, at the atomic level, the complete donor-substrate binding process from the bulk solvent to the ApNGT active-site, and the key intermediate states of UDP-Glc during its loading dynamics. We are able to determine the critical transition event that limits the overall binding rate, which guides us to pinpoint the key ApNGT residues dictating the donor-substrate entry. The functional roles of several identified gating residues were evaluated through site-directed mutagenesis and enzymatic assays. Two single-point mutations, N471A and S496A, could profoundly enhance the catalytic activity of ApNGT. Our work provides deep mechanistic insights into the structural dynamics of the donor-substrate loading process for ApNGT, which sets a rational basis for design of novel NGT variants with desired substrate specificity.

Breaking the Solubility Limit of LiNO3 in Carbonate Electrolyte Assisted by BF3 to Construct a Stable SEI Film for Dendrite-Free Lithium Metal Batteries

Lithium (Li) metal is regarded as a potential candidate for the next generation of lithium secondary batteries, but it has poor cycling stability with the broadly used carbonate-based electrolytes due to the uncontrollable dendritic growth and low Coulombic efficiency (CE). LiNO3 is an effective additive and its limited solubility (<800 ppm) in carbonate-based electrolytes is still a challenge, as reported. Herein, using BF3 (Lewis acid) is proposed to enhance the solubility of LiNO3 in carbonate-based electrolytes. The dissolved NO3 - can be involved in the first solvation shell of Li+, reducing the coordination number of PF6 - and EC (ethylene carbonate). In addition, the NO3 - is proved to be preferentially reduced on Li metal by differential electrochemical mass spectrometry so that the decomposition of PF6 - and EC is suppressed. Therefore, a SEI layer containing Li3N can be obtained, which exhibits high lithium-ion conductivity, achieving even and dense Li deposits. Consequently, the CE of Li||Cu cell with BF3/LiNO3 can be increased to 98.07%. Moreover, the capacity retention of Li||LiFePO4 with a low N/P ratio (3:1) is as high as 90% after 300 cycles (≈1500 h). This work paved a new way for incorporating LiNO3 into carbonate-based electrolytes and high-performance lithium metal batteries.

Healing grief - an online self-help intervention programme for bereaved Chinese with prolonged grief: study protocol for a randomised controlled trial

Background: In China, mental health services do not currently meet the needs of bereaved people with symptoms of prolonged grief disorder (PGD). Internet-based grief interventions may help fill this gap, but such programmes have not yet been developed or evaluated in China. The proposed study aims to investigate the effectiveness, acceptability, and feasibility of an online self-help intervention programme named Healing Grief for bereaved Chinese with prolonged grief, and to explore the psychological mechanisms of potential improvements.Methods: We designed a two-arm randomised controlled trial. At least 128 participants will be randomly assigned to either an Internet-based intervention group or a waitlist-control group. The Internet-based intervention will be developed based on the dual process model, integrating techniques of psychoeducation, behavioural activation, cognitive reappraisal, and meaning reconstruction, and will be delivered via expressive writing. The intervention comprises six modules, with two sessions in each module, and requires participants to complete two sessions per week and complete the intervention in 6 weeks. The primary outcomes include effectiveness, acceptability, and feasibility. The effectiveness will be assessed by measures of prolonged grief, posttraumatic stress, anxiety, and depressive symptoms. Acceptability and feasibility will be evaluated using survey and interview on user experience characteristics. Secondary outcomes include moderators and mediators, such as dual process coping, grief rumination, mindfulness, and continuing bond, to explore the psychological mechanisms of potential improvement. Assessments will take place at pre-intervention, post-intervention, and 3-month follow-up.Conclusion: The proposed study will determine the effectiveness, acceptability, and feasibility of the newly developed online self-help intervention for bereaved Chinese with prolonged grief and clarify how the intervention helps with symptom improvements. Such an intervention may play an important role in easing the imbalance between the delivery and receipt of bereavement psychological services in China.

Evolution of human H3N2 influenza virus receptor specificity has substantially expanded the receptor-binding domain site

Hemagglutinins (HAs) from human influenza viruses descend from avian progenitors that bind α2-3-linked sialosides and must adapt to glycans with α2-6-linked sialic acids on human airway cells to transmit within the human population. Since their introduction during the 1968 pandemic, H3N2 viruses have evolved over the past five decades to preferentially recognize human α2-6-sialoside receptors that are elongated through addition of poly-LacNAc. We show that more recent H3N2 viruses now make increasingly complex interactions with elongated receptors while continuously selecting for strains maintaining this phenotype. This change in receptor engagement is accompanied by an extension of the traditional receptor-binding site to include residues in key antigenic sites on the surface of HA trimers. These results help explain the propensity for selection of antigenic variants, leading to vaccine mismatching, when H3N2 viruses are propagated in chicken eggs or cells that do not contain such receptors.

By Carrot or by Stick: The Influence of Encouraging and Discouraging Facial Feedback on Implicit Rule Learning

Implicit learning refers to the process of unconsciously learning complex knowledge through feedback. Previous studies investigated the influences of different types of feedback (e.g., social and non-social feedback) on implicit learning. This study focused on the social information presented in the learning situation and tried to explore the effects of different social feedback on implicit rule learning. We assigned participants randomly into an encouraging facial feedback group (happy expression for correct answer, neutral but not negative expression for incorrect answer) and a discouraging facial feedback group (neutral but not happy expression for correct answer, negative expression for incorrect answer). The implicit learning task included four difficulty levels, and social feedback was presented in the learning phase but not the testing phase in two experiments. The only difference between the two experiments was that the sad face used as negative feedback in Experiment 1 was replaced with an angry face in Experiment 2 to enhance the ecological validity of the discouraging facial feedback group. These two experiments yielded consistent results: the performances in the encouraging facial feedback group were more accurate in both the learning and the testing phases at all difficulty levels. These findings indicated that the influence of encouraging social feedback for a better implicit learning achievement was stable and established a new groundwork for future research on incentive-based education, making it critical to investigate the impact of various forms of encouraging-based education on learning.

Uncovering the Redox Shuttle Degradation Mechanism of Ether Electrolytes in Sodium-Ion Batteries and its Inhibition Strategy

Ether-based electrolytes exhibit excellent performance when applied in different anode materials of sodium ion batteries (SIBs), but their exploration on cathode material is deficient and the degradation mechanism is still undiscovered. Herein, various battery systems with different operation voltage ranges are designed to explore the electrochemical performance of ether electrolyte. It is found for the first time that the deterioration mechanism of ether electrolyte is closely related to the "redox shuttle" between cathode and low-potential anode. The "shuttle" is discovered to occur when the potential of anodes is below 0.57 V, and the gas products coming from "shuttle" intermediates are revealed by differential electrochemical mass spectrometry (DEMS). Moreover, effective inhibition strategies by protecting low-potential anodes are proposed and verified; ethylene carbonate (EC) is found to be very effective as an additive by forming an inorganics-rich solid electrolyte interphase (SEI) on low-potential anodes, thereby suppressing the deterioration of ether electrolytes. This work reveals the failure mechanism of ether-based electrolytes applied in SIBs and proposes effective strategies to suppress the "shuttle," which provides a valuable guidance for advancing the application of ether-based electrolytes in SIBs.

The Role of In-Group and Out-Group Facial Feedback in Implicit Rule Learning

Implicit learning refers to the fact that people acquire new knowledge (structures or rules) without conscious awareness. Previous studies have shown that implicit learning is affected by feedback. However, few studies have investigated the role of social feedback in implicit learning concretely. Here, we conducted two experiments to explore how in-group and out-group facial feedback impact different difficulty levels of implicit rule learning. In Experiment 1, the Chinese participants in each group could only see one type of facial feedback, i.e., either in-group (East Asian) or out-group (Western) faces, and learned the implicit rule through happy and sad facial expressions. The only difference between Experiment 2 and Experiment 1 was that the participants saw both the in-group and out-group faces before group assignment to strengthen the contrast between the two group identities. The results showed that only in Experiment 2 but not Experiment 1 was there a significant interaction effect in the accuracy of tasks between the difficulty levels and groups. For the lowest difficulty level, the learning accuracy of the in-group facial feedback group was significantly higher than that of the out-group facial feedback group, whereas this did not happen at the two highest levels of difficulty. In conclusion, when the contrast of group identities was highlighted, out-group feedback reduced the accuracy of the least difficult task; on the contrary, there was no accuracy difference between out-group and in-group feedback conditions. These findings have extensively important implications for our understanding of implicit learning and improving teaching achievement in the context of educational internationalization.

Recombinant Slit2 suppresses neuroinflammation and Cdc42-mediated brain infiltration of peripheral immune cells via Robo1-srGAP1 pathway in a rat model of germinal matrix hemorrhage

BACKGROUND

Germinal matrix hemorrhage (GMH) is a devastating neonatal stroke, in which neuroinflammation is a critical pathological contributor. Slit2, a secreted extracellular matrix protein, plays a repulsive role in axon guidance and leukocyte chemotaxis via the roundabout1 (Robo1) receptor. This study aimed to explore effects of recombinant Slit2 on neuroinflammation and the underlying mechanism in a rat model of GMH.

METHODS

GMH was induced by stereotactically infusing 0.3 U of bacterial collagenase into the germinal matrix of 7-day-old Sprague Dawley rats. Recombinant Slit2 or its vehicle was administered intranasally at 1 h after GMH and daily for 3 consecutive days. A decoy receptor recombinant Robo1 was co-administered with recombinant Slit2 after GMH. Slit2 siRNA, srGAP1 siRNA or the scrambled sequences were administered intracerebroventricularly 24 h before GMH. Neurobehavior, brain water content, Western blotting, immunofluorescence staining and Cdc42 activity assays were performed.

RESULTS

The endogenous brain Slit2 and Robo1 expressions were increased after GMH. Robo1 was expressed on neuron, astrocytes and infiltrated peripheral immune cells in the brain. Endogenous Slit2 knockdown by Slit2 siRNA exacerbated brain edema and neurological deficits following GMH. Recombinant Slit2 (rSlit2) reduced neurological deficits, proinflammatory cytokines, intercellular adhesion molecules, peripheral immune cell markers, neuronal apoptosis and Cdc42 activity in the brain tissue after GMH. The anti-neuroinflammation effects were reversed by recombinant Robo1 co-administration or srGAP1 siRNA.

CONCLUSIONS

Recombinant Slit2 reduced neuroinflammation and neuron apoptosis after GMH. Its anti-neuroinflammation effects by suppressing onCdc42-mediated brain peripheral immune cells infiltration was at least in part via Robo1-srGAP1 pathway. These results imply that recombinant Slit2 may have potentials as a therapeutic option for neonatal brain injuries.

[Malignant peripheral nerve sheath tumor: a clinicopathological analysis]

Objective: To investigate the clinicopathological, immunophenotypic, and genetic features of malignant peripheral nerve sheath tumor (MPNST). Methods: Twenty-three cases of MPNST were diagnosed at the Jiangsu Province Hospital (the First Affiliated Hospital of Nanjing Medical University), China, between January 2012 and December 2022 and thus included in the study. EnVision immunostaining and next-generation sequencing (NGS) were used to examine their immunophenotypical characteristics and genomic aberrations, respectively. Results: There were 10 males and 13 females, with an age range of 11 to 79 years (median 36 years), including 14 cases of neurofibromatosis type I-associated MPNST and 9 cases of sporadic MPNST. The tumors were located in extremities (7 cases), trunk (4 cases), neck and shoulder (3 cases), chest cavity (3 cases), paraspinal area (2 cases), abdominal cavity (2 cases), retroperitoneum (1 case), and pelvic cavity (1 case). Morphologically, the tumors were composed of dense spindle cells arranged in fascicles. Periphery neurofibroma-like pattern was found in 73.9% (17/23) of the cases. Under low magnification, alternating hypercellular and hypocellular areas resembled marbled appearance. Under high power, the tumor cell nuclei were irregular, presenting with oval, conical, comma-like, bullet-like or wavy contour. In 7 cases, the tumor cells demonstrated marked cytological pleomorphism and rare giant tumor cells. The mitotic figures were commonly not less than 3/10 HPF, and geographic necrosis was often noted. Immunohistochemically, tumor cells were positive for S-100 (14/23, 60.9%) and SOX10 (11/23, 47.8%). The loss of the CD34-positive fibroblastic network encountered in neurofibromas was observed in 14/17 of the MPNST cases. The loss of H3K27me3 expression was observed in 82.6% (19/23) of the cases. Moreover, SDHA and SDHB losses were presented in one case. NGS revealed that NF1 gene loss of function (germline or somatic) were found in all 5 cases tested. Furthermore, four cases accompanied with somatic mutations of SUZ12 gene and half of them had somatic mutations of TP53 gene, while one case with germline mutation in SDHA gene and somatic mutations in FAT1, BRAF, and KRAS genes. Available clinical follow-up was obtained in 19 cases and ranged from 1 to 67 months. Four patients died of the disease, all of whom had the clinical history of neurofibromatosis type Ⅰ. Conclusions: MPNST is difficult to be differentiated from a variety of spindle cell tumors due to its wide spectrum of histological morphology and complex genetic changes. H3K27me3 is a useful diagnostic marker, while the loss of CD34 positive fibroblastic network can also be a diagnostic feature of MPNST. NF1 gene inactivation mutations and complete loss of PRC2 activity are the common molecular diagnostic features, but other less commonly recurred genomic aberrations might also contribute to the MPNST pathogenesis.

Uniform Densification of Garnet Electrolyte for Solid-State Lithium Batteries

Highly uniformly dense garnet type solid-state electrolyte plays a significant role in determining the performance of solid-state lithium batteries. Herein, a rational powder-covering sintering strategy is proposed and demonstrated, in which narrow-particle-size-distribution fine powder and uniform sintering temperature distribution are considered as very significant factors. It is suggested that powder materials with wider particle size distribution dramatically decrease the densified level of electrolytes. Slow temperature elevating rate and the overhead structure of bearing table are found to be beneficial to uniform densification. Moreover, the uniform densification process of sintering solid-state electrolyte is studied both microscopically and macroscopically, which can be divided into three phases according to the grain growing evolution and linear shrinkage patterns. The ionic conductivity of the as-prepared Li6.4 La3 Zr1.4 Ta0.6 O12 (LLZTO) garnet electrolyte is determined to be 0.73 mS cm-1 at 303 K with an activation energy of 0.37 eV. The Li/LLZTO/Li symmetric cell exhibits a small interfacial impedance of 8.49 Ω cm2 and a high apparent critical current density of 2.15 mA cm-2 and also can be cycled for 1000 h continuously without short-circuit. Such results indicate the good feasibility of as-proposed sintering strategy to prepare uniformly dense garnet type solid-state electrolytes for solid-state lithium batteries.

Investigation of the Catalytic Mechanism of a Soluble N-glycosyltransferase Allows Synthesis of N-glycans at Noncanonical Sequons

The soluble N-glycosyltransferase from Actinobacillus pleuropneumoniae (ApNGT) can establish an N-glycosidic bond at the asparagine residue in the Asn-Xaa-Ser/Thr consensus sequon and is one of the most promising tools for N-glycoprotein production. Here, by integrating computational and experimental strategies, we revealed the molecular mechanism of the substrate recognition and following catalysis of ApNGT. These findings allowed us to pinpoint a key structural motif (215DVYM218) in ApNGT responsible for the peptide substrate recognition. Moreover, Y222 and H371 of ApNGT were found to participate in activating the acceptor Asn. The constructed models were supported by further crystallographic studies and the functional roles of the identified residues were validated by measuring the glycosylation activity of various mutants against a library of synthetic peptides. Intriguingly, with particular mutants, site-selective N-glycosylation of canonical or noncanonical sequons within natural polypeptides from the SARS-CoV-2 spike protein could be achieved, which were used to investigate the biological roles of the N-glycosylation in membrane fusion during virus entry. Our study thus provides in-depth molecular mechanisms underlying the substrate recognition and catalysis for ApNGT, leading to the synthesis of previously unknown chemically defined N-glycoproteins for exploring the biological importance of the N-glycosylation at a specific site.

[Prevalence of obesity and its association with dietary patterns: a cohort study among Tibetan pastoralists in Qinghai Province]

Objectives: To explore obesity prevalence and its association with dietary patterns among Tibetan pastoralists during the urbanization transition in Qinghai Province. Methods: Using an open cohort study design, 1 003 subjects were enrolled at baseline in 2018, 599 were followed up, and 1 012 were newly recruited in 2022. A total of 1 913 adults over 18 years were included in the study, and a questionnaire survey and health examination were conducted. Factor analysis was used to identify dietary patterns, and a mixed-effects model was used to analyze the association between dietary patterns and obesity. Results: From 2018 to 2022, the prevalence rates of overweight, obesity, and central obesity were 27.6%, 33.8%, and 54.6%, respectively. Age-sex-standardized prevalence of obesity and central obesity increased. Three dietary patterns were identified: the modern pattern was characterized by frequent consumption of pork, poultry, processed meat, fresh fruits, sugary drinks, salty snacks, etcetera; the urban pattern was characterized by frequent consumption of refined carbohydrates, beef and mutton, vegetables and eggs, etcetera; and pastoral pattern featured frequent consumption of tsamba, Tibetan cheese, buttered/milk tea, and whole-fat dairy products. After adjusting for demographic characteristics, socioeconomic status, and lifestyle factors, compared with the T1, subjects in the T3 of urban pattern scores were more likely to be overweight (OR=2.09, 95%CI: 1.10-3.95) and overweight/obese (OR=1.23, 95%CI: 1.00-1.51), whereas those in the T3 of pastoral pattern scores had a lower risk of overweight (OR=0.45, 95%CI: 0.24-0.84), obesity (OR=0.81, 95%CI: 0.69-0.95), overweight/obesity (OR=0.75, 95%CI: 0.61-0.91) and central obesity (OR=0.58, 95%CI: 0.38-0.89). Conclusions: Prevalence of obesity and central obesity was high among Tibetan pastoralists during the urbanization transition. Urban dietary pattern was a risk factor for overweight and overweight/obesity, whereas pastoral dietary pattern was a protective factor for overweight, obesity, overweight/obesity, and central obesity. Tailored interventions are needed to improve local people's health.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510  GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510  GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02<x<0.08, with direct sensitivity to the sign of the gluon contribution.

[The rise and fall of the leprosy clinic in Ru Gao in the North of Jiangsu in the period of the Republic of China]

The North of Jiangsu was a traditional area for leprosy in Chinese history. In the period of the Republic of China, one of the largest leprosy clinics in China was established in Ru Gao (Jugao) with the help of Chinese and foreign charitable organizations, the Chinese central government and some squires. It was the only large clinic for leprosy in the North of Jiangsu. It was officially opened in 1924, attached to the Presbyterian Church hospital, and was closed in 1927 after the breakout of the civil war. It reopened in May 1933, hosted by a leprologist, Lee S. Huizenga. Ru Gao (Jugao) leprosy clinic treated around 1,000 lepers in the North of Jiangsu with medicines and language communication. The establishment of the leprosy clinic made a historical contribution in terms of preventing leprosy from spreading to Shanghai. It closed in the spring of 1938 because of the invasion of the Japanese military.

Recent progress in targeting the sialylated glycan-SIGLEC axis in cancer immunotherapy

Malignant tumors are complex structures composed of cancer cells and tumor microenvironmental cells. In this complex structure, cells cross-talk and interact, thus jointly promoting cancer development and metastasis. Recently, immunoregulatory molecule-based cancer immunotherapy has greatly improved treatment efficacy for solid cancers, thus enabling some patients to achieve persistent responses or cure. However, owing to the development of drug-resistance and the low response rate, immunotherapy against the available targets PD-1/PD-L1 or CTLA-4 has limited benefits. Although combination therapies have been proposed to enhance the response rate, severe adverse effects are observed. Thus, alternative immune checkpoints must be identified. The SIGLECs are a family of immunoregulatory receptors (known as glyco-immune checkpoints) discovered in recent years. This review systematically describes the molecular characteristics of the SIGLECs, and discusses recent progress in areas including synthetic ligands, monoclonal antibody inhibitors, and Chimeric antigen receptor T (CAR-T) cells, with a focus on available strategies for blocking the sialylated glycan-SIGLEC axis. Targeting glyco-immune checkpoints can expand the scope of immune checkpoints and provide multiple options for new drug development.

GBC: a parallel toolkit based on highly addressable byte-encoding blocks for extremely large-scale genotypes of species

Whole -genome sequencing projects of millions of subjects contain enormous genotypes, entailing a huge memory burden and time for computation. Here, we present GBC, a toolkit for rapidly compressing large-scale genotypes into highly addressable byte-encoding blocks under an optimized parallel framework. We demonstrate that GBC is up to 1000 times faster than state-of-the-art methods to access and manage compressed large-scale genotypes while maintaining a competitive compression ratio. We also showed that conventional analysis would be substantially sped up if built on GBC to access genotypes of a large population. GBC's data structure and algorithms are valuable for accelerating large-scale genomic research.

The effect of polyphenols in post stroke adults: A systematic review of randomised controlled trials

BACKGROUND

After a stroke, survivors are often left with significant disabilities and are at a greater risk of recurrent strokes. It is vital stroke survivors receive effective treatments to assist with rehabilitation and reduce risk factors for secondary stroke. Observational and preclinical studies have highlighted the promising role of polyphenols in these regards.

METHODS

A systematic review of original research which assessed the role of polyphenols on health outcomes in post stroke adults was conducted. PROQUEST, SCOPUS (Elsevier), MEDLINE (EBSCO), Embase and Cochrane Library databases were searched up to the 29th of October 2021.

RESULTS

A total of 9 studies met the full inclusion criteria and were included in this review. Several classes of polyphenols were assessed including hydroxybenzoic acids, stilbenes and flavonoids. Numerous health outcomes were assessed including vascular function, stroke disability, blood pressure, blood glucose and c-reactive protein. The majority of the studies included in this review (n = 8) note improvements in the polyphenol groups for at least one outcome measure. However, small sample sizes, short trial length and reporting bias prevent firm conclusions from being drawn.

CONCLUSION

This review provides promising preliminary evidence that polyphenols may be beneficial for post stroke adults, however, more research is required. To ensure reliable methodology and replication of results, future studies should include outcome statistics and effect sizes. Trials with a longer duration and large sample size should also be considered.

Analysis of Inner Flow in a Multi-Stage Double-Suction Centrifugal Pump Using the Detached Eddy Simulation Method

In order to analyze the inner flow in a multi-stage double-suction centrifugal pump, which is regarded as a common way of knowing the current characteristics of the pump and as the basis of optimization for better performance, a numerical simulation considering the velocity field distribution characteristics and pressure fluctuation propagation law using the detached eddy simulation method was conducted. Additionally, the principle of entropy generation was put to use to quantify and compare the energy loss of different components. The results reveal that the existence of unstable flow structures in the first-stage impeller and a large number of vortical structures in the back-channel result in reduced operational efficiency of the pump. Furthermore, the pressure fluctuation intensity reaches its maximum with 0.15 at the blade trailing edge, which propagates to the tongue region of the forward flow channel and the double-volute under the low rates condition. Additionally, the main frequency of the monitoring points in the inter-stage flow channel and volute is basically located at a frequency of 198.667 Hz, which is twice the blade frequency. Consequently, the wall entropy production accounting for nearly 25% cannot be ignored and that the loss mainly occurs in the double-volute and the inter-stage flow channel due to the occurrence of irregular flow in the above components with more than 50%. The outcomes of this research present a valuable point of reference for the optimization of structural design in multistage turbomachines with various applications.

A Fresh One-Step Spray Pyrolysis Approach to Prepare Nickel-Rich Cathode Material for Lithium-Ion Batteries

The Ni-rich layered cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) with high specific capacity and acceptable rate performance is one of the key cathode materials for high-energy-density lithium-ion batteries. Coprecipitation, the widely utilized method in the precursor synthesis of NCM811 materials, however, suffers long synthetic processes and challenges in uniform element distribution. The spray pyrolysis method is able to prepare oxide precursors in seconds where all transition-metal elements are well distributed, but the difficulty of lithium distribution will also arise when the lithium salts are added in the subsequent sintering process. Herein, a fresh one-step spray pyrolysis approach is proposed for preparing high-performance NCM811 cathode materials by synthesizing lithium-contained precursors in which all elements are well distributed at a molecular level. The precursors with folded morphology and exceptional uniformity are successfully obtained at a low pyrolysis temperature of 300 °C by an acetate system. Furthermore, the final products commendably inherit the folded morphology of the precursors and exhibit excellent cyclic retentions of 94.6% and 88.8% after 100 and 200 cycles at 1 C (1 C = 200 mA g-1), respectively.

Longitudinal Relationship between Mobility Device Use, Falls and Fear of Falling (FOF) Differed by Frailty Status among Community-Dwelling Older Adults

OBJECTIVES

This study examined the longitudinal relationship between mobility device use, falls and fear of falling (FOF) among community-dwelling older adults by frailty status over a one-year follow-up.

DESIGN

A longitudinal cohort study.

SETTING

Communities in the United States.

PARTICIPANTS

Community-dwelling older adults from the National Health and Aging Trends Study, a nationally representative survey of Medicare Beneficiaries in the United States (N=5,896).

MEASUREMENTS

Based on yes or no response to the corresponding items for the variables, fall-related outcomes were determined separately including falls and FOF. Falls were assessed by asking participants whether they had a fall and if they had fallen down more than one time. FOF was measured by asking participants whether they worried about falling and if this worry ever limited activities. Mobility device use was determined by asking whether participants used any type of mobility devices and the number of devices used, including cane, walker, wheelchair and scooter. Frailty was assessed using the frailty phenotype. Multinomial logistic regression models were conducted to examine the association between mobility device use and fall-related outcomes among older adults by frailty status.

RESULTS

At Year 1, 28.6% of participants reported using mobility devices. Among robust participants, using one mobility device had 3.58 times higher risks of FOF with fear-related activity restriction (FAR) than non-device users (95% CI: 1.10-11.65). Cane-only robust users had 5.94 and 2.18 times higher risks of FOF with and without FAR (95% CI: 1.80-19.57; 95% CI: 1.12-4.22) than non-device users. Among pre-frail participants, using one mobility device was associated with recurrent falls and FOF with FAR (RRR=2.02, 95% CI: 1.30-3.14; RRR=2.13, 95% CI: 1.25-3.63). Using ≥2 devices was associated with one fall (RRR=2.08, 95% CI: 1.30-3.33), recurrent falls (RRR=2.92, 95% CI: 1.62-5.25) and FOF with FAR (RRR=2.84, 95% CI: 1.34-6.02). Pre-frail cane-only users were more likely to have one fall (RRR=1.57, 95% CI: 1.06-2.32), recurrent falls (RRR=2.36, 95% CI: 1.48-3.77) and FOF with FAR (RRR=2.08, 95% CI: 1.12-3.87) than non-device users. The number of mobility device used and the use of canes failed to be significantly associated with fall-related outcomes among frail participants.

CONCLUSION

The number of mobility devices used and the only use of canes were associated with fall-related outcomes among robust and pre-frail individuals. Further research is needed to develop targeted strategies for preventing falls and FOF among older adults with mobility device use, particularly for those in the early stages of frailty.

Long-term exposure to low concentrations of polycyclic aromatic hydrocarbons and alterations in platelet indices: A longitudinal study in China

Long-term exposure to low polycyclic aromatic hydrocarbon (PAH) concentration may ave detrimental effects, including changing platelet indices. Effects of chronic exposure to low PAH concentrations have been evaluated in cross-sectional, but not in longitudinal studies, to date. We aimed to assess the effects of long-term exposure to the low-concentration PAHs on alterations in platelet indices in the Chinese population. During 2014–2017, we enrolled 222 participants who had lived in a village in northern China, 1–2 km downwind from a coal plant, for more than 25 years, but who were not employed by the plant or related businesses. During three follow-ups, annually in June, demographic information and urine and blood samples were collected. Eight PAHs were tested: namely 2-hydroxynaphthalene, 1-hydroxynaphthalene, 2-hydroxyfluorene, 9-hydroxyfluorene (9-OHFlu), 2-hydroxyphenanthrene (2-OHPh), 1-hydroxyphenanthrene (1-OHPh), 1-hydroxypyrene (1-OHP), and 3-hydroxybenzo [a] pyrene. Five platelet indices were measured: platelet count (PLT), platelet distribution width (PDW), mean platelet volume (MPV), platelet crit, and the platelet-large cell ratio. Generalized mixed and generalized linear mixed models were used to estimate correlations between eight urinary PAH metabolites and platelet indices. Model 1 assessed whether these correlations varied over time. Models 2 and 3 adjusted for additional personal information and personal habits. We found the following significant correlations: 2-OHPh (Model1 β₁ = 18.06, Model2 β₂ = 18.54, Model β₃ = 18.54), 1-OHPh (β₁ = 16.43, β₂ = 17.42, β₃ = 17.42), 1-OHP(β₁ = 13.93, β₂ = 14.03, β₃ = 14.03) with PLT, as well as 9-OHFlu with PDW and MPV (odds ratio or Model3 OR_PDW[95%CI] = 1.64[1.3–2.06], OR_MPV[95%CI] = 1.33[1.19–1.48]). Long-term exposure to low concentrations of PAHs, indicated by2-OHPh, 1-OHPh, 1-OHP, and 9-OHFlu, as urinary biomarkers, affects PLT, PDW, and MPV. 9-OHFlu increased both PDW and MPV after elimination of the effects of other PAH exposure modes.