23 research outputs found
Unconventional ferromagnetism and spin-triplet superconductivity in the imbalanced Kagome-lattice Hubbard model
Unconventional ferromagnetism and superconductivity in the imbalanced
kagome-lattice Hubbard model are investigated by the mean-field theory and
determinant quantum Monte Carlo method. Due to the asymmetric band structure of
kagome lattice, the spin- ferromagnetic order intrinsically exists in the
system, which is first enhanced by the interaction, and then continuously
destructed after reaching a maximum at a moderate interaction strength. In
contrast, the -plane ferromagnetism develops only above a critical
interaction, which is estimated to be by finite-size
scaling. We further verify the nature of the above transverse magnetic
transition, and demonstrate it belongs to the three-dimensional
universality class. Finally, we study the superconducting property, and reveal
the possible superconducting state has a triplet -wave pairing symmetry. Our
results uncover the exotic quantum states induced by the interactions on kagome
lattice, and provide important insights regarding the interplay between
electronic correlations and geometry frustrations
Diabetic Osteoporosis: A Review of Its Traditional Chinese Medicinal Use and Clinical and Preclinical Research
Aim. The incidence of diabetic osteoporosis (DOP) is increasing due to lack of effective management over the past few decades. This review aims to summarize traditional Chinese medicine (TCM) suitability in the pathogenesis and clinical and preclinical management of DOP. Methods. Literature sources used were from Medline (Pubmed), CNKI (China Knowledge Resource Integrated Database), and CSTJ (China Science and Technology Journal Database) online databases. For the consultation, keywords such as diabetic osteoporosis (DOP), TCM, clinical study, animal experiment, toxicity, and research progress were used in various combinations. Around 100 research papers and reviews were visited. Results. Liver-spleen-kidney insufficiency may result in development of DOP. 18 clinical trials are identified to use TCM compound prescriptions for management of patients with DOP. TCM herbs and their active ingredients are effective in preventing the development of DOP in streptozotocin (STZ) and alloxan as well as STZ combined with ovariectomy insulted rats. Among them, most frequently used TCM herbs in clinical trials are Radix Astragali, Radix et Rhizoma Salviae Miltiorrhizae, Radix Rehmanniae Preparata, and Herba Epimedii. Some of TCM herbs also exhibit toxicities in clinical and preclinical research. Conclusions. TCM herbs may act as the novel sources of anti-DOP drugs by improving bone and glucolipid metabolisms. However, the pathogenesis of DOP and the material base of TCM herbs still merit further study
Health impacts of parental migration on left-behind children and adolescents: a systematic review and meta-analysis.
BACKGROUND: Globally, a growing number of children and adolescents are left behind when parents migrate. We investigated the effect of parental migration on the health of left behind-children and adolescents in low-income and middle-income countries (LMICs). METHODS: For this systematic review and meta-analysis we searched MEDLINE, Embase, CINAHL, the Cochrane Library, Web of Science, PsychINFO, Global Index Medicus, Scopus, and Popline from inception to April 27, 2017, without language restrictions, for observational studies investigating the effects of parental migration on nutrition, mental health, unintentional injuries, infectious disease, substance use, unprotected sex, early pregnancy, and abuse in left-behind children (aged 0-19 years) in LMICs. We excluded studies in which less than 50% of participants were aged 0-19 years, the mean or median age of participants was more than 19 years, fewer than 50% of parents had migrated for more than 6 months, or the mean or median duration of migration was less than 6 months. We screened studies using systematic review software and extracted summary estimates from published reports independently. The main outcomes were risk and prevalence of health outcomes, including nutrition (stunting, wasting, underweight, overweight and obesity, low birthweight, and anaemia), mental health (depressive disorder, anxiety disorder, conduct disorders, self-harm, and suicide), unintentional injuries, substance use, abuse, and infectious disease. We calculated pooled risk ratios (RRs) and standardised mean differences (SMDs) using random-effects models. This study is registered with PROSPERO, number CRD42017064871. FINDINGS: Our search identified 10â284 records, of which 111 studies were included for analysis, including a total of 264â967 children (n=106â167 left-behind children and adolescents; n=158â800 children and adolescents of non-migrant parents). 91 studies were done in China and focused on effects of internal labour migration. Compared with children of non-migrants, left-behind children had increased risk of depression and higher depression scores (RR 1·52 [95% CI 1·27-1·82]; SMD 0·16 [0·10-0·21]), anxiety (RR 1·85 [1·36-2·53]; SMD 0·18 [0·11-0·26]), suicidal ideation (RR 1·70 [1·28-2·26]), conduct disorder (SMD 0·16 [0·04-0·28]), substance use (RR 1·24 [1·00-1·52]), wasting (RR 1·13 [1·02-1·24]) and stunting (RR 1·12 [1·00-1·26]). No differences were identified between left-behind children and children of non-migrants for other nutrition outcomes, unintentional injury, abuse, or diarrhoea. No studies reported outcomes for other infectious diseases, self-harm, unprotected sex, or early pregnancy. Study quality varied across the included studies, with 43% of studies at high or unclear risk of bias across five or more domains. INTERPRETATION: Parental migration is detrimental to the health of left-behind children and adolescents, with no evidence of any benefit. Policy makers and health-care professionals need to take action to improve the health of these young people. FUNDING: Wellcome Trust
Localization of matter waves in lattice systems with moving disorder
We study the localization phenomena in a one-dimensional lattice system with
a uniformly moving disordered potential. At a low moving velocity, we find a
sliding localized phase in which the initially localized matter wave
adiabatically follows the moving potential without diffusion, thus resulting in
an initial state memory in the many-body dynamics. Such an intriguing localized
phase distinguishes itself from the standard Anderson localization in two
aspects: it is not robust against interaction, but persists in the presence of
slowly varying perturbations. Such a sliding localized phase can be understood
as a consequence of interference between the wavepacket paths under moving
quasi-periodic potentials with various periods that are incommensurate with the
lattice constant. The experimental realization and detection were also
discussed..Comment: 11 page
Boosting Evaporative Cooling Performance with Microporous Aerogel
Hydrogel-based evaporative cooling with a low carbon footprint is regarded as a promising technology for thermal regulation. Yet, the efficiency of hydrogel regeneration at night generally mismatches with vapor evaporation during the day, resulting in a limited cooling time span, especially in arid regions. In this work, we propose an efficient approach to improve hydrogel cooling performance, especially the cooling time span, with a bilayer structure, which comprises a bottom hydrogel layer and an upper aerogel layer. The microporous aerogel layer can reduce the saturation vapor density at the hydrogel surface by employing daytime radiative cooling, together with increased convective heat transfer resistance by thermal insulation, thus boosting the duration of evaporative cooling. Specifically, the microstructure of porous aerogel for efficient radiative cooling and vapor transfer is synergistically optimized with a cooling performance model. Results reveal that the proposed structure with a 2-mm-thick SiO2 aerogel can reduce the temperature by 1.4 °C, meanwhile extending the evaporative cooling time span by 11 times compared to a single hydrogel layer
Order Effects in Online Product Recommendation: A Scenario-based Analysis
Existing research on recommender systems has mostly focused on developing algorithms to predict the degrees to which a consumer may like a product. Recommended products are usually presented based on their predicted ratings in descending order. Considering the cognitive process of online consumers, when users evaluate the recommended products in sequence, the descending order may not necessarily be a good solution to increase consumers\u27 willingness to purchase. Drawing upon the evaluability perspective and the order effects theory, we formulate a scenario where each product has two attributes, one of which can be evaluated independently while the other is difficult to evaluate without comparison. Analysis shows that in two out of the three cases of the scenario, presenting the most recommended product in the second place will result in higher consumer willingness to pay. The findings provide a new angle for understanding the behavioral implications of using recommender systems in ecommerce
Association of PD-1 and PD-L1 Genetic Polymorphyisms with Type 1 Diabetes Susceptibility
Aims. The programmed death- (PD-) 1/PD-1 ligand (PD-L) pathway plays an important role in regulating T cell activation and maintaining peripheral tolerance. Accumulated studies showed that PD-1/PD-L1 pathway was involved in the development of type 1 diabetes (T1DM). Since the genetic background of type 1 diabetes differs greatly among the different population, we aim to investigate the association of genetic polymorphisms in PD-1 and PD-L1 with T1DM susceptibility in Chinese population. Methods. In total, 166 T1DM patients and 100 healthy controls were enrolled into the study. Genomic DNA was extracted from 4âmL peripheral blood samples collected from each subject. Genotyping of 8 selected SNPs of PD-1 and PD-L1 was carried out by the pyrosequencing PSQ 24 System using PyroMark Gold reagents (QIAGEN). Results. SNP rs4143815 in PD-L1 was significantly associated with T1DM. People carrying the C allele of rs4143815 suffering less risk of T1DM and T1DM patients with G/G genotype showed higher levels of autoantibody (AAB) positive incidence compared with C allele carriers. No significant associations were found in other SNPs. Conclusions. Our results indicate that rs4143815 of PD-L1 is significantly associated with T1DM and may serve as a new biomarker to predict the T1DM susceptibility
Does Surface Roughness Necessarily Increase the Fouling Propensity of Polyamide Reverse Osmosis Membranes by Humic Acid?
Surface roughness has crucial influence on the fouling
propensity
of thin film composite (TFC) polyamide reverse osmosis (RO) membranes.
A common wisdom is that rougher membranes tend to experience more
severe fouling. In this study, we compared the fouling behaviors of
a smooth polyamide membrane (RO-s) and a nanovoid-containing rough
polyamide membrane (RO-r). Contrary to the traditional belief, we
observed more severe fouling for RO-s, which can be ascribed to its
uneven flux distribution caused by the âfunnel effectâ.
Additional tracer filtration tests using gold nanoparticles revealed
a more patchlike particle deposition pattern, confirming the adverse
impact of âfunnel effectâ on membrane water transport.
In contrast, the experimentally observed lower fouling propensity
of the nanovoid-containing rough membrane can be explained by: (1)
the weakened âfunnel effectâ thanks to the presence
of nanovoids, which can regulate the water transport pathway through
the membrane and (2) the decreased average localized flux over the
membrane surface due to the increased effective filtration area for
the nanovoid-induced roughness features. The current study provides
fundamental insights into the critical role of surface roughness in
membrane fouling, which may have important implications for the future
development of high-performance antifouling membranes
Controllable Preparation of CoreâShell AuâAg Nanoshuttles with Improved Refractive Index Sensitivity and SERS Activity
Recent
studies have conclusively shown that the plasmonic performance
of Au nanostructures can be enhanced by incorporating Ag. Here, we
developed a simple and robust approach for preparing coreâshell
AuâAg nanoshuttles (NSs) using single-crystal Au nanorods (NRs)
as cores. Upon tailoring the temperature of the reaction system containing
alkaline glycine buffer (pH 8.5), exceptionally monodisperse AuâAg
NSs with sharp tips and tunable shell thickness could be routinely
achieved in high yield through an epitaxial growth process. In particular,
high-resolution transmission electron microscopy and nitric acid corrosive
experiments revealed that the shells of these NSs consisted of a homogeneous
AuâAg alloy, rather than pure Ag or Au as previously reported.
It was found that glycine played an important role in determining
the final metal contents of the shell by regulating the reduction
kinetics. In addition, the obatined AuâAg NSs with sharp tips
were shown to have significantly improved refractive index sensitivity
and surface-enhanced Raman scattering activity relative to the original
Au NRs, making these materials promising for biomedical applications,
such as biosensing and biolabeling
Phase transformation barrier modulation of CsPbI3 films via PbI3â complex for efficient all-inorganic perovskite photovoltaics
Cesium lead iodide (CsPbI3) has gained great attention due to its thermal stability and appropriate bandgap (â1.73 eV) at black (Îł) phase potentially suitable for tandem solar cells. However, it is challenging to obtain CsPbI3 film with desired black phase. Herein, we fabricate kinetically favorable Îł-CsPbI3 thin films by stoichiometry modulation, where in-situ 2D GIWAXS measurement was innovatively performed to illustrate the phase transition process of the precursor films, to aid a full picture study on the entire film evolution process. Conceptually different from introducing other extrinsic species, the cogenetic doping by excessive cesium iodide is found to tailor energy barriers for phase transformations during both the film formation and ageing process simultaneously. During film growth, excessive CsI affects the formation of PbâI complex in the precursor solution, which facilitates the ÎŽ to Îł phase transformation. Also, the Cs-rich resultant film could suppress Îł to ÎŽ phase transformation. The corresponding CsPbI3 solar cells deliver a PCE of 16.68% without performance loss at continuous maximum power point output (MPP) for ~175 h under continuous illumination in a N2 glovebox. This work highlights the importance of precursors chemistry and provides guidelines to adjust the phase transformation barrier in CsPbI3 films without any foreign additives