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1.
Brain ; 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38739753

RESUMEN

Human brain organoids represent a remarkable platform for modeling neurological disorders and a promising brain repair approach. However, the effects of physical stimulation on their development and integration remain unclear. Here, we report that low-intensity ultrasound significantly increases neural progenitor cell proliferation and neuronal maturation in cortical organoids. Histological assays and single-cell gene expression analyses reveal that low-intensity ultrasound improves the neural development in cortical organoids. Following organoid grafts transplantation into the injured somatosensory cortices of adult mice, longitudinal electrophysiological recordings and histological assays reveal that ultrasound-treated organoid grafts undergo advanced maturation. They also exhibit enhanced pain-related gamma-band activity and more disseminated projections into the host brain than the untreated groups. Finally, low-intensity ultrasound ameliorates neuropathological deficits in a microcephaly brain organoid model. Hence, low-intensity ultrasound stimulation advances the development and integration of brain organoids, providing a strategy for treating neurodevelopmental disorders and repairing cortical damage.

2.
Cereb Cortex ; 34(2)2024 01 31.
Artículo en Inglés | MEDLINE | ID: mdl-38342690

RESUMEN

Migraine without aura is a multidimensional neurological disorder characterized by sensory, emotional, and cognitive symptoms linked to structural and functional abnormalities in the anterior cingulate cortex. Anterior cingulate cortex subregions play differential roles in the clinical symptoms of migraine without aura; however, the specific patterns and mechanisms remain unclear. In this study, voxel-based morphometry and seed-based functional connectivity were used to investigate structural and functional alterations in the anterior cingulate cortex subdivisions in 50 patients with migraine without aura and 50 matched healthy controls. Compared with healthy controls, patients exhibited (1) decreased gray matter volume in the subgenual anterior cingulate cortex, (2) increased functional connectivity between the bilateral subgenual anterior cingulate cortex and right middle frontal gyrus, and between the posterior part of anterior cingulate cortex and right middle frontal gyrus, orbital part, and (3) decreased functional connectivity between the anterior cingulate cortex and left anterior cingulate and paracingulate gyri. Notably, left subgenual anterior cingulate cortex was correlated with the duration of each attack, whereas the right subgenual anterior cingulate cortex was associated with migraine-specific quality-of-life questionnaire (emotion) and self-rating anxiety scale scores. Our findings provide new evidence supporting the hypothesis of abnormal anterior cingulate cortex subcircuitry, revealing structural and functional abnormalities in its subregions and emphasizing the potential involvement of the left subgenual anterior cingulate cortex-related pain sensation subcircuit and right subgenual anterior cingulate cortex -related pain emotion subcircuit in migraine.


Asunto(s)
Giro del Cíngulo , Migraña sin Aura , Humanos , Giro del Cíngulo/diagnóstico por imagen , Migraña sin Aura/diagnóstico por imagen , Corteza Cerebral , Dolor/diagnóstico por imagen , Emociones , Imagen por Resonancia Magnética/métodos
3.
J Am Chem Soc ; 146(5): 2919-2927, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38277794

RESUMEN

Dicarboxylic acids and derivatives are important building blocks in organic synthesis, biochemistry, and the polymer industry. Although catalytic dicarboxylation with CO2 represents a straightforward and sustainable route to dicarboxylic acids, it is still highly challenging and limited to generation of achiral or racemic dicarboxylic acids. To date, catalytic asymmetric dicarboxylation with CO2 to give chiral dicarboxylic acids has not been reported. Herein, we report the first asymmetric dicarboxylation of 1,3-dienes with CO2 via Cu catalysis. This strategy provides an efficient and environmentally benign route to chiral dicarboxylic acids with high regio-, chemo-, and enantioselectivities. The copper self-relay catalysis, that is, Cu-catalyzed boracarboxylation of 1,3-dienes to give carboxylated allyl boronic ester intermediates and subsequent carboxylation of C-B bonds to give dicarboxylates, is key to the success of this dicarboxylation. Moreover, this protocol exhibits broad substrate scope, good functional group tolerance, easy product derivatizations, and facile synthesis of chiral liquid crystalline polyester and drug-like scaffolds.

4.
J Am Chem Soc ; 146(21): 14864-14874, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38754389

RESUMEN

The exploitation of carbon dioxide (CO2) as a sustainable, plentiful, and harmless C1 source for the catalytic synthesis of enantioenriched carboxylic acids has long been acknowledged as a pivotal task in synthetic chemistry. Herein, we present a current-driven nickel-catalyzed reductive carboxylation reaction with CO2 fixation, facilitating the formation of C(sp3)-C(sp2) bonds by circumventing the handling of moisture-sensitive organometallic reagents. This electroreductive protocol serves as a practical platform, paving the way for the synthesis of enantioenriched propargylic carboxylic acids (up to 98% enantiomeric excess) from racemic propargylic carbonates and CO2. The efficacy of this transformation is exemplified by its successful utilization in the asymmetric total synthesis of (S)-arundic acid, (R)-PIA, (S)-chizhine D, (S)-cochlearin G, and (S,S)-alexidine, thereby underscoring the potential of asymmetric electrosynthesis to achieve complex molecular architectures sustainably.

5.
Chaos ; 34(3)2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38442235

RESUMEN

Detecting early warning indicators for abrupt dynamical transitions in complex systems or high-dimensional observation data are essential in many real-world applications, such as brain diseases, natural disasters, and engineering reliability. To this end, we develop a novel approach: the directed anisotropic diffusion map that captures the latent evolutionary dynamics in the low-dimensional manifold. Then three effective warning signals (Onsager-Machlup indicator, sample entropy indicator, and transition probability indicator) are derived through the latent coordinates and the latent stochastic dynamical systems. To validate our framework, we apply this methodology to authentic electroencephalogram data. We find that our early warning indicators are capable of detecting the tipping point during state transition. This framework not only bridges the latent dynamics with real-world data but also shows the potential ability for automatic labeling on complex high-dimensional time series.

6.
Angew Chem Int Ed Engl ; 63(22): e202403401, 2024 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-38527960

RESUMEN

Upgrading CO2 to value-added chiral molecules via catalytic asymmetric C-C bond formation is a highly important yet challenging task. Although great progress on the formation of centrally chiral carboxylic acids has been achieved, catalytic construction of axially chiral carboxylic acids with CO2 has never been reported to date. Herein, we report the first catalytic asymmetric synthesis of axially chiral carboxylic acids with CO2, which is enabled by nickel-catalyzed dynamic kinetic asymmetric reductive carboxylation of racemic aza-biaryl triflates. A variety of important axially chiral carboxylic acids, which are valuable but difficult to obtain via catalysis, are generated in an enantioconvergent version. This new methodology features good functional group tolerance, easy to scale-up, facile transformation and avoids cumbersome steps, handling organometallic reagents and using stoichiometric chiral materials. Mechanistic investigations indicate a dynamic kinetic asymmetric transformation process induced by chiral nickel catalysis.

7.
J Am Chem Soc ; 145(44): 24328-24337, 2023 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-37878504

RESUMEN

We report herein an organic charge transfer cocrystal complex, consisting of a stable radical TPVr and an electron acceptor TCNQF4, as a rare sort of all-organic-based magnetic bistable materials with a thermally activated magnetic hysteresis loop over the temperature range from 170 to 260 K. Detailed X-ray crystallographic studies and theoretical calculations revealed that while a π-associated radical anion dimer was formed upon an integer charge transfer process from TPVr to the TCNQF4 molecules within the cocrystal lattice, the resulting TCNQF4·- π-dimers were found to exhibit varied intradimer π-stacking distances and singly occupied molecular orbital overlaps at different temperatures, thus yielding two different singlet states with distinct singlet-triplet gaps above and below the loop, which eventually contributed to the thermally excited molecular magnetic bistability.

8.
Appl Opt ; 62(24): 6389-6400, 2023 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-37706831

RESUMEN

Light absorption and scattering exist in the underwater environment, which can lead to blurring, reduced brightness, and color distortion in underwater images. Polarized images have the advantages of eliminating underwater scattering interference, enhancing contrast, and detecting material information of the object in underwater detection. In this paper, from the perspective of polarization imaging, different concentrations (0.15 g/ml, 0.30 g/ml, and 0.50 g/ml), different wave bands (red, green, and blue), different materials (copper, wood, high-density PVC, aluminum, cloth, foam, cloth sheet, low-density PVC, rubber, and porcelain tile), and different depths (10 cm, 20 cm, 30 cm, and 40 cm) are set up in a chamber for the experimental environment. By combining the degradation mechanism of underwater images and the analysis of polarization detection results, it is proved that the degree of polarization images have greater advantages than degree of linear polarization images, degree of circular polarization images, S1, S2, and S3 images, and visible images underwater. Finally, a fusion algorithm of underwater visible images and polarization images based on compressed sensing is proposed to enhance underwater degraded images. To improve the quality of fused images, we introduce orthogonal matching pursuit (OMP) in the high-frequency part to improve image sparsity and consistency detection in the low-frequency part to improve the image mutation phenomenon. The fusion results show that the peak SNR values of the fusion result maps using OMP in this paper are improved by 32.19% and 22.14% on average over those using backpropagation and subspace pursuit methods. With different materials and concentrations, the underwater image enhancement algorithm proposed in this paper improves information entropy, average gradient, and standard deviation by 7.76%, 18.12%, and 40.8%, respectively, on average over previous algorithms. The image NIQE value shows that the image quality obtained by this paper's algorithm is improved by about 69.26% over the original S0 image.

9.
J Transl Med ; 20(1): 218, 2022 05 13.
Artículo en Inglés | MEDLINE | ID: mdl-35562743

RESUMEN

BACKGROUND: Early diagnosis and treatment of chronic pancreatitis (CP) are limited. In this study, St13, a co-chaperone protein, was investigated whether it constituted a novel regulatory target in CP. Meanwhile, we evaluated the value of micro-PET/CT in the early diagnosis of CP. METHODS: Data from healthy control individuals and patients with alcoholic CP (ACP) or non-ACP (nACP) were analysed. PRSS1 transgenic mice (PRSS1Tg) were treated with ethanol or caerulein to mimic the development of ACP or nACP, respectively. Pancreatic lipid metabolite profiling was performed in human and PRSS1Tg model mice. The potential functions of St13 were investigated by crossing PRSS1Tg mice with St13-/- mice via immunoprecipitation and lipid metabolomics. Micro-PET/CT was performed to evaluate pancreatic morphology and fibrosis in CP model. RESULTS: The arachidonic acid (AA) pathway ranked the most commonly dysregulated lipid pathway in ACP and nACP in human and mice. Knockout of St13 exacerbated fatty replacement and fibrosis in CP model. Sdf2l1 was identified as a binding partner of St13 as it stabilizes the IRE1α-XBP1s signalling pathway, which regulates COX-2, an important component in AA metabolism. Micro-PET/CT with 68Ga-FAPI-04 was useful for evaluating pancreatic morphology and fibrosis in CP model mice 2 weeks after modelling. CONCLUSION: St13 is functionally activated in acinar cells and protects against the cellular characteristics of CP by binding Sdf2l1, regulating AA pathway. 68Ga-FAPI-04 PET/CT may be a very valuable approach for the early diagnosis of CP. These findings thus provide novel insights into both diagnosis and treatment of CP.


Asunto(s)
Células Acinares , Endorribonucleasas , Animales , Humanos , Ratones , Células Acinares/metabolismo , Ácido Araquidónico/metabolismo , Proteínas Portadoras/metabolismo , Endorribonucleasas/metabolismo , Fibrosis , Radioisótopos de Galio , Ratones Noqueados , Tomografía Computarizada por Tomografía de Emisión de Positrones , Proteínas Serina-Treonina Quinasas , Tripsina/metabolismo , Proteínas Supresoras de Tumor/metabolismo
10.
Inorg Chem ; 61(7): 3058-3071, 2022 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-35130695

RESUMEN

The propensity of uranyl for hydrolysis in aqueous environments prevents precise control of uranyl species in the scenarios of on-demand separation and tailored synthesis. Herein, using cucurbit[7]uril (CB[7]) as the macrocyclic molecule and 4,4'-bipyridine-N,N'-dioxide (DPO) as the string molecule, we propose a new kind of multidentate pseudorotaxane ligand, DPO@CB[7] for capturing uranyl species at different pH's. With the aprotic nature of DPO for metal coordination, the coordination ability of the DPO@CB[7] ligand is less affected by pH and can work in a wide range of pH's. Furthermore, by adaptive uranyl coordination, this aprotic pseudorotaxane ligand achieves effective recognition for different uranyl species ranging from monomeric to tetrameric originating from hydrolysis at varying pH's, and four novel uranyl-rotaxane compounds (URC1-4) are successfully obtained. Single-crystal X-ray diffraction analysis reveals that the DPO@CB[7] ligand coordinates with uranyl centers from monomeric to tetrameric in four different modes, as a result of structural flexibility of the DPO@CB[7] pseudorotaxane ligand. A detailed discussion for conformation flexibility of the DPO@CB[7] ligand has been conducted on the position changes of the DPO ligand trapped in the CB[7], which thus reveals good adaptivity of DPO@CB[7] that is noncovalently bonded as a supramolecular motif. In addition, characterization of the physicochemical properties of URC1 and URC2 with high phase purity, including powder X-ray diffraction (PXRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), and luminescence properties, are also provided. This work provides a good case of an adaptive pseudorotaxane ligand for the recognition and capture of different uranyl species and will bring valuable hints to the design of multifunctional supramolecular ligands for actinide separation in the future.

11.
Inorg Chem ; 61(45): 17993-18001, 2022 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-36330783

RESUMEN

The involvement of the 2-phosphaethynolate anion species with ambident nucleophilic properties serves as an essential protocol for synthesizing oxygen-bound or phosphorus-bound complexes. This work mainly describes the synthesis and characterization of U, Th, and Ti phosphaethynolate complexes featuring a preferential O-coordination fashion. Among these complexes, the first examples of a Ti(IV)-OCP complex 3A, Th(IV)-OCP complex 3B, and U(IV)-OCP complex 3C were assembled by a salt metathesis reaction between M(TrapenTMS)(Cl) (M = Ti, Th, U) and NaOCP(dioxane)2.5 and were all crystallographically characterized. The structural similarity of this series of phosphaethynolate complexes allows us to compare the bonding properties of d- and f-block elements in the corresponding compounds. The well-established density functional theory (DFT) computational method was employed to explore the electronic structures and covalency in M-O bonding, and the results showed a consistent pattern. The calculation result showed that 2-phosphaethynolate complexes exhibited the covalency trend of U-O > Th-O > Ti-O due to the involvement of 5f orbitals.

12.
Andrologia ; 54(11): e14637, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36357339

RESUMEN

Transverse testicular ectopia is a rare anomaly characterized by both testes descending through a single inguinal canal. The objective of this study was to investigate the pathogenesis, diagnosis, and treatment of transverse testicular ectopia (TTE) with persistent Mullerian duct syndrome (PMDS), and to deepen the understanding of the disease in clinical. A retrospective analysis of the clinical manifestation, diagnosis, and treatment of two children suffering from TTE with PMDS was conducted. Previous studies on the characteristics, diagnosis, and treatment of this disease were reviewed. The two patients were treated with laparoscopy-assisted transseptal orchidopexy-inguinal evaluation. After the surgery, the two patients recovered well. The follow-up visits were done 3 months after the operation. An ultrasound examination confirmed that the two patients had testes in the orthotopic position and normal size. TTE with PMDS is an exceedingly rare disease. The patients manifested cryptorchidism on one side; contralateral inguinal hernia was suspected. Detailed physical and ultrasound examinations before the operation are the key to the early diagnosis of TTE. Laparoscopic evaluation is helpful for the diagnosis and finding of other abnormalities. Surgical treatment is the only method to cure the disease; long-term follow-up is needed after TTE operation.


Asunto(s)
Criptorquidismo , Trastorno del Desarrollo Sexual 46,XY , Masculino , Niño , Humanos , Estudios Retrospectivos , Trastorno del Desarrollo Sexual 46,XY/diagnóstico , Trastorno del Desarrollo Sexual 46,XY/cirugía , Orquidopexia/efectos adversos , Criptorquidismo/diagnóstico , Criptorquidismo/diagnóstico por imagen , Testículo/diagnóstico por imagen , Testículo/cirugía , Testículo/anomalías
13.
Nano Lett ; 21(1): 651-657, 2021 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-33283521

RESUMEN

The global COVID-19 pandemic has changed many aspects of daily lives. Wearing personal protective equipment, especially respirators (face masks), has become common for both the public and medical professionals, proving to be effective in preventing spread of the virus. Nevertheless, a detailed understanding of respirator filtration-layer internal structures and their physical configurations is lacking. Here, we report three-dimensional (3D) internal analysis of N95 filtration layers via X-ray tomography. Using deep learning methods, we uncover how the distribution and diameters of fibers within these layers directly affect contaminant particle filtration. The average porosity of the filter layers is found to be 89.1%. Contaminants are more efficiently captured by denser fiber regions, with fibers <1.8 µm in diameter being particularly effective, presumably because of the stronger electric field gradient on smaller diameter fibers. This study provides critical information for further development of N95-type respirators that combine high efficiency with good breathability.


Asunto(s)
COVID-19/prevención & control , Respiradores N95/virología , Pandemias , SARS-CoV-2/ultraestructura , Microbiología del Aire , COVID-19/transmisión , COVID-19/virología , Aprendizaje Profundo , Filtración/estadística & datos numéricos , Humanos , Imagenología Tridimensional , Microscopía Electrónica de Rastreo , Respiradores N95/normas , Respiradores N95/estadística & datos numéricos , Nanopartículas/ultraestructura , Pandemias/prevención & control , Tamaño de la Partícula , Polipropilenos , Porosidad , Textiles/virología , Tomografía por Rayos X
14.
J Mol Cell Cardiol ; 157: 66-76, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33932464

RESUMEN

Obesity induces inflammation and oxidative stress, and ultimately leads to vasodilatory dysfunction in which Transient receptor potential vanilloid type 4 (TRPV4) and Nicotinamide Adenine Dinucleotide Phosphate Oxidase (Nox2) have been reported to be involved. However, little attention has been paid to the role of the TRPV4-Nox2 complex in these problems. The purpose of this study was to figure out the role of the TRPV4-Nox2 complex in obesity-induced inflammation, oxidative stress, and vasodilatory dysfunction. Using fluorescence resonance energy transfer and immunoprecipitation assays, we found enhanced TRPV4 and Nox2 interactions in obese mice. Using q-PCR, fluorescent dye dihydroethidium staining, and myotonic techniques, we found that obesity caused inflammation, oxidative stress, and vasodilatory dysfunction. Using adeno-associated viruses, we found that enhancement or attenuation of TRPV4-Nox2 interaction altered the vaso-function. Based on these findings, we found a small-molecule drug, M12, that interrupted the TRPV4-Nox2 interaction, thereby reducing inflammatory factors and reactive oxygen species production and helping to restore the vasodilatory function. In summary, our results revealed a new mechanism by which obesity-induced inflammation, oxidative stress, and vasodilatory dysfunction is caused by enhanced TRPV4-Nox2 interactions. Using M12 to interrupt the TRPV4-Nox2 interaction may have anti-inflammatory and anti-oxidative stress effects and help restore vasodilatory function and thus provide a new therapeutic approach to obesity.


Asunto(s)
Endotelio Vascular/metabolismo , Inflamación/etiología , Inflamación/metabolismo , NADPH Oxidasa 2/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Canales Catiónicos TRPV/metabolismo , Animales , Biomarcadores , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Células Endoteliales/metabolismo , Inflamación/patología , Mediadores de Inflamación/metabolismo , Ratones , Ratones Noqueados , Ratones Obesos , Mutación , NADPH Oxidasa 2/genética , Obesidad/complicaciones , Obesidad/metabolismo , Estrés Oxidativo , Unión Proteica/efectos de los fármacos , Canales Catiónicos TRPV/genética , Vasodilatación/genética
15.
Nat Chem Biol ; 20(9): 1106-1107, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39152214
16.
Ann Hepatol ; 20: 100245, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32877762

RESUMEN

INTRODUCTION AND OBJECTIVES: Radical resection remains the only curative treatment for liver tumors. Although associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) can increase the resection rate, huge controversy exists for high reported mortality and morbidity. This study was to evaluate the efficacy and safety of modified ALPPS procedure. PATIENTS AND METHODS: Patients who were performed ALPPS in single-center in recent 5 years were retrospectively reviewed. The modified strategy included strict patient selection, precise future liver remnant (FLR) assessment and operation planning, and usage of minimally invasive methods. Data including clinical records, functional FLR increase, complications, and overall survival (OS) were analyzed. RESULTS: Sixty patients underwent modified ALPPS procedure and recovered well. No severe complications happened after the 1-stage operation, and the increasing FLR was 179.3 cm3(±72.4 cm3), with similar functional FLR increase. The OS was 20.0 months (±4.5month). CONCLUSIONS: ALPPS could be a feasible treatment for complex liver tumors by risk-reduced modification. It could be expected to provide long-term survival for patients without enough FLR.


Asunto(s)
Carcinoma Hepatocelular/cirugía , Colangiocarcinoma/cirugía , Hepatectomía/métodos , Neoplasias Hepáticas/cirugía , Vena Porta/cirugía , Adulto , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , China , Colangiocarcinoma/mortalidad , Colangiocarcinoma/patología , Femenino , Humanos , Ligadura/métodos , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Masculino , Persona de Mediana Edad , Selección de Paciente , Estudios Retrospectivos , Tasa de Supervivencia , Resultado del Tratamiento
17.
Nano Lett ; 20(7): 5544-5552, 2020 07 08.
Artículo en Inglés | MEDLINE | ID: mdl-32484683

RESUMEN

The COVID-19 pandemic is currently causing a severe disruption and shortage in the global supply chain of necessary personal protective equipment (e.g., N95 respirators). The U.S. CDC has recommended use of household cloth by the general public to make cloth face coverings as a method of source control. We evaluated the filtration properties of natural and synthetic materials using a modified procedure for N95 respirator approval. Common fabrics of cotton, polyester, nylon, and silk had filtration efficiency of 5-25%, polypropylene spunbond had filtration efficiency 6-10%, and paper-based products had filtration efficiency of 10-20%. An advantage of polypropylene spunbond is that it can be simply triboelectrically charged to enhance the filtration efficiency (from 6 to >10%) without any increase in pressure (stable overnight and in humid environments). Using the filtration quality factor, fabric microstructure, and charging ability, we are able to provide an assessment of suggested fabric materials for homemade facial coverings.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/prevención & control , Máscaras , Pandemias/prevención & control , Neumonía Viral/prevención & control , Textiles , Aerosoles , Microbiología del Aire , COVID-19 , Infecciones por Coronavirus/transmisión , Electricidad , Diseño de Equipo , Filtración , Humanos , Máscaras/provisión & distribución , Microscopía Electrónica de Rastreo , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología , Tamaño de la Partícula , Equipo de Protección Personal/provisión & distribución , Neumonía Viral/transmisión , SARS-CoV-2
18.
Water Sci Technol ; 84(12): 3928-3940, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34928853

RESUMEN

A hydrodynamic model is developed for rainfall-runoff on asphalt pavement using two-dimensional shallow water equations. A simple yet precise expression is presented to compute flow velocity in order to alleviate the problems associated with numerical instabilities due to small water depths of thin sheet flow. The developed model performed well against measured data and numerical results in two segments. Then, the model was applied to study the influence of highway horizontal alignment, drainage manner, rainfall pattern, surface roughness and geometric parameters on pavement runoff. The results demonstrate that: (i) the influence of highway horizontal alignment on pavement runoff is nonsignificant, while that of drainage manner and the pavement surface roughness is significant. Great differences are observed in flow depth under concentrated drainage and overflow drainage conditions, especially in the area beyond 6 m away from the highway center axis; (ii) remarkable differences in maximum flow depth and peak runoff are presented under uneven and even rainfall conditions, while no great differences are found under three uneven rainfall conditions (front type, center front type and back front type); (iii) the sensitivity of the geometric parameters to the maximum flow depth from strong to weak is cross slope, width, slope length, and longitudinal slope under overflow drainage condition; while that is width, slope length, longitudinal slope and cross slope under concentrated drainage condition.


Asunto(s)
Hidrodinámica , Hidrocarburos
19.
Chin J Traumatol ; 24(2): 88-93, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33526264

RESUMEN

PURPOSE: This research examined road traffic injury mortality and morbidity disparities across of country development status, and discussed the possibility of reducing country disparities by various actions to accelerate the pace of achieving Sustainable Development Goals target 3.6 - to halve the number of global deaths and injuries from road traffic accidents by 2020. METHODS: Data for road traffic mortality, morbidity, and socio-demographic index (SDI) were extracted by country from the estimates of the Global Burden of Disease study, and the implementation of the three types of national actions (legislation, prioritized vehicle safety standards, and trauma-related post-crash care service) were extracted from the Global Status Report on Road Safety by World Health Organization. We fitted joinpoint regression analysis to identify and quantify the significant rate changes from 2011 to 2017. RESULTS: Age-adjusted road traffic mortality decreased substantially for all the five SDI categories from 2011 to 2017 (by 7.52%-16.08%). Age-adjusted road traffic mortality decreased significantly as SDI increased in the study time period, while age-adjusted morbidity generally increased as SDI increased. Subgroup analysis by road user yielded similar results, but with two major differences during the study period of 2011 to 2017: (1) pedestrians in the high SDI countries experienced the lowest mortality (1.68-1.90 per 100,000 population) and morbidity (110.45-112.72 per 100,000 population for incidence and 487.48-491.24 per 100,000 population for prevalence), and (2) motor vehicle occupants in the high SDI countries had the lowest mortality (4.07-4.50 per 100,000 population) but the highest morbidity (428.74-467.78 per 100,000 population for incidence and 1025.70-1116.60 per 100,000 population for prevalence). Implementation of the three types of national actions remained nearly unchanged in all five SDI categories from 2011 to 2017 and was consistently stronger in the higher SDI countries than in the lower SDI countries. Lower income nations comprise the heaviest burden of global road traffic injuries and deaths. CONCLUSION: Global road traffic deaths would decrease substantially if the large mortality disparities across country development status were reduced through full implementation of proven national actions including legislation and law enforcement, prioritized vehicle safety standards and trauma-related post-crash care services.


Asunto(s)
Lesiones Accidentales/epidemiología , Lesiones Accidentales/mortalidad , Accidentes de Tránsito/estadística & datos numéricos , Países en Desarrollo/estadística & datos numéricos , Peatones/estadística & datos numéricos , Desarrollo Sostenible , Lesiones Accidentales/prevención & control , Accidentes de Tránsito/legislación & jurisprudencia , Accidentes de Tránsito/prevención & control , Humanos , Incidencia , Renta/estadística & datos numéricos , Morbilidad , Prevalencia , Factores Socioeconómicos , Desarrollo Sostenible/tendencias , Factores de Tiempo
20.
Angew Chem Int Ed Engl ; 60(25): 14068-14075, 2021 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-33793030

RESUMEN

Reductive carboxylation of organo (pseudo)halides with CO2 is a powerful method to provide carboxylic acids quickly. Notably, the catalytic reductive carbo-carboxylation of unsaturated hydrocarbons via CO2 fixation is a highly challenging but desirable approach for structurally diverse carboxylic acids. There are only a few reports and no examples of alkenes via transition metal catalysis. We report the first asymmetric reductive carbo-carboxylation of alkenes with CO2 via nickel catalysis. A variety of aryl (pseudo)halides, such as aryl bromides, aryl triflates and inert aryl chlorides of particular note, undergo the reaction smoothly to give important oxindole-3-acetic acid derivatives bearing a C3-quaternary stereocenter. This transformation features mild reaction conditions, wide substrate scope, facile scalability, good to excellent chemo-, regio- and enantioselectivities. The method highlights the formal synthesis of (-)-Esermethole, (-)-Physostigmine and (-)-Physovenine, and the total synthesis of (-)-Debromoflustramide B, (-)-Debromoflustramine B and (+)-Coixspirolactam A; thereby, opening an avenue for the total synthesis of chiral natural products with CO2 .

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