662 research outputs found
A General Procedure for the Construction of 2‑Alkyl-Substituted Vinyl Sulfonyl Fluoride
A series of compact and multifunctional 2-alkyl-substituted
vinyl
sulfonyl fluorides were efficiently prepared from the corresponding
alkyl iodides and 2-chloroprop-2-ene-1-sulfonyl fluoride (CESF). This
Giese-type radical approach provided new and general access to alkenyl
sulfonyl fluorides, including structures that would otherwise be challenging
to synthesize with previously established methods. A correspondingly
large collection of derivatization reactions was also demonstrated
on the alkenyl sulfonyl fluorides
Connecting the ‘Workshop of the World’: Intra- and Extra-Service Networks of the Pearl River Delta City-Region
<p>Zhang X. and Kloosterman R. C. Connecting the ‘workshop of the world’: intra- and extra-service networks of the Pearl River Delta city-region, <i>Regional Studies</i>. Most research on globalization and city-regions in developing countries has focused on manufacturing activities, disregarding the considerable growth of producer services. Drawing on the Interlocking Network Model, this article presents a first analysis of the intra- and extra-service networks of the Pearl River Delta city-region in China. The central question is how cities in the Pearl River Delta are (re)positioned in the regional urban networks and which national and global cities are their major external connections in the service economy. The result reveals a new pattern of producer-services-led development that differs from the former industrialization experience in the region.</p
Predicting Dermal Exposure to Gas-Phase Semivolatile Organic Compounds (SVOCs): A Further Study of SVOC Mass Transfer between Clothing and Skin Surface Lipids
Dermal exposure to indoor gas-phase
semivolatile organic compounds
(SVOCs) has recently received a great deal of attention, and this
has included evaluating the role of clothing in this process. Several
models have been developed to assess dermal exposure to SVOCs, based
on the transient mass transfer of SVOCs from air to dermal capillaries.
Assumptions of these models are either that clothing completely retards
SVOC transport, or that there is an air gap of constant thickness
between the clothing and the surface of the skin, which may lead to
errors in the model calculations. To solve this problem, we tried
to describe SVOC transport between clothing and epidermis by considering
two parallel processes: partitioning of SVOCs by direct contact (ignored
in existing models), and Fickian diffusion through the air gap. Predictions
from the present model agree well with the experimental data found
in the literature (dermal uptake of diethyl phthalate (DEP) and di-<i>n</i>-butyl phthalate (DnBP) of a clothed participant). This
study provides a useful tool to accurately assess dermal exposure
to indoor SVOCs, especially for evaluating the effects of clothing
on dermal exposure
Charge Stripe Formation in Molecular Ferroelectric Organohalide Perovskites for Efficient Charge Separation
Despite
rapid progress in the efficiency of organohalide perovskite
based solar cells, physical mechanisms underlying their efficient
charge separation and slow charge recombination still elude us. Here
we provide direct evidence of spontaneous charge separation via first-principles
simulations. The excitons are predicted to self-organize into stripes
of photoexcited electrons and holes, spatially separated as effective
channels for charge transport. The rotation of organic cations deforms
the inorganic framework, and as the deformation reaches a critical
value, a direct band gap transforms to an indirect one, and the photoexcited
electrons rotate in alignment with the deformation-induced electric
fields. The latter triggers a Stark effect which in turn leads to
the formation of charge stripes. The interplay between dynamic disorder,
ionic bonding, and polarization is responsible for the formation of
the charge stripes and the indirect band gap, both of which could
lead to efficient charge separation and reduced charge recombination
in the organohalide perovskites
MOESM1 of Regioselective semi-synthesis of 6-isomers of 5,8-O-dimethyl ether of shikonin derivatives via an ‘intramolecular ring-closing/ring-opening’ strategy as potent anticancer agents
Additional file 1. Additional figures
Amphiphilic Interlayer Regulated Interfacial Polymerization for Constructing Polyamide Nanofiltration Membranes with High Perm-Selectivity of Mono-/Divalent Salts
High-quality thin-film composite
(TFC) membranes with high selectivity
and permeability have great significance owing to their practical
applications, specifically for the accurate differentiation of monovalent
and divalent ions. However, the trade-off effect between selectivity
and permeability is still a big challenge due to the difficult structure
adjustment of the selective layer. Herein, polydopamine (PDA) functionalized
with a hydrophobic long alkane chain was first explored as a functional
amphiphilic interlayer to synthesize high-quality TFC membranes via
a confined interfacial polymerization (IP) reaction. The amphiphilic
interlayer not only restricted the formation of the polyamide (PA)
matrix in the pores of the substrate but also accelerated spatially
more homogeneous polymerization and formed a PA active layer with
a more uniform pore size distribution. The method may provide an effective
principle for the construction of versatile polyamide-based membranes
with high perm-selectivity on various supports. The NaCl/Na2SO4 separation factor of the D-8/PA membrane reached as
high as 204.07, while the flux increased up to 25.71 L m–2 h–1 bar–1. This progress provides
a more feasible way for the construction of high-quality TFC membranes
with a devisable and creative amphiphilic interlayer for industrial
application
Table1_Causal effects of various types of physical activities on psychiatric disorders: a Mendelian randomization study.xls
BackgroundPsychiatric disorders (PD) pose a significant burden, with vast prevalence and mortality, inflicting substantial costs on individuals and society. Despite its widespread prevalence, the complex pathogenesis of PD remains elusive, leading to limited and challenging therapeutic development. An emerging risk factor for chronic diseases, prolonged sedentary behavior, contrasts with the therapeutic potential of exercise, regardless of its intensity, for various ailments, including PD. Yet, the diversity in exercise modalities and intensities may offer varied impacts on health. This study, leveraging Mendelian Randomization (MR), seeks to investigate the causal relationship between exercise and PD, aiming to elucidate the optimal exercise modality and intensity for PD mitigation while addressing potential confounders.MethodsThis study employed a Mendelian randomization analysis using the genome-wide association study (GWAS) database to investigate the causal relationship between types of physical activity and psychiatric disorders. Sensitivity analysis was conducted to demonstrate the reliability and robustness of the results.ResultsIn the past 4 weeks, engaging in a substantial amount of DIY physical activity was found to have a causal relationship with psychiatric disorders (IVW: OR = 0.228, 95% CI: 0.113–0.461, P = 0.000038). As for the types of exercises, there may be a potential causal association between aerobic training (including swimming, cycling, fitness, and bowling) and psychiatric disorders (IVW: OR = 0.322, 95% CI = 0.148–0.704, P = 0.004). However, there was no causal relationship found between mild DIY physical activity and psychiatric disorders (IVW: OR = 0.918, 95% CI = 0.417–2.021, P = 0.831). Furthermore, it seems that there is no causal relationship between vigorous exercise and psychiatric disorders (IVW: OR = 2.705, 95% CI = 0.081–3.419, P = 0.578).ConclusionOur study confirms that only a certain level of training activity can have a protective effect on psychiatric disorders, while mild physical activity or vigorous training does not have an impact on psychiatric disorders.</p
Microfluidics Fabrication of Monodisperse Biocompatible Phospholipid Vesicles for Encapsulation and Delivery of Hydrophilic Drug or Active Compound
We
encapsulate the hydrophilic anti-cancer drug doxurubicin hydrochloride
(DOX) with about 94% drug encapsulation efficiency, either alone or
with nanomagnetite, in monodisperse biocompatible phospholipid vesicles.
Glass capillary microfluidics is used to generate monodisperse water
in oil in water (w/o/w) double-emulsion templates with a core–shell
structure by using a mixture of liquid unsaturated phospholipids and
powdered saturated phospholipid. This combination would overcome the
low transition temperature of unsaturated powdered phospholipid and
the solubility limitation of saturated phospholipid, as well as improving
the fabrication of stable monodisperse phospholipid vesicles. The
double-emulsion droplet is controlled from 50 to 200 μm according
to different flow rates, and the final phospholipid vesicles are retained
after a solvent removal step by dewetting. DOX-loaded phospholipid
vesicles show sustained release compared with free DOX water solution.
The in vitro cell viability of 100 μg/mL phospholipid vesicles
on HeLa or MCF-7 cells after 24 h incubation at 310 K is above 90%,
confirming the excellent biocompatibility of the phospholipid vesicles.
These biocompatible phospholipid vesicles are promising oral drug
delivery vehicles for biomedical applications and magnetic resonance
imaging contrast agents for biomedical diagnosis
Effects of Engineered Nanoparticles on the Enantioselective Transformation of Metalaxyl Agent and Commercial Metalaxyl in Agricultural Soils
The adsorption coefficient
of racemic metalaxyl onto an agriculture
soil was small and nonenantioselective. Biotransformation was the
predominant pathway for the elimination of <i>R</i>-metalaxyl,
while abiotic and biotransformation made a comparable contribution
to the degradation of <i>S</i>-metalaxyl. Metalaxyl acid
was the main transformation intermediate. The enantiomer fraction
of metalaxyl decreased with an increase in its initial spike concentration
or the presence of the co-constituents in metalaxyl commercial products.
Under simulated solar irradiation, the presence of TiO<sub>2</sub> promoted the overall transformation kinetics through enhanced biotransformation
and extra photoinduced chemical reactions. The promotion was enantioselective
and thereafter changed the enantiomer fraction. The results obtained
in this study showed that some achiral parameters, although they have
no direct impact on enantioselective reactions with enantiomers, can
significantly affect the enantioselective transformation of racemic
metalaxyl. Thus, our results indicate that the contribution of chemical
interactions on the enantioselective transformation of chiral pesticides
may be underestimated
Preparation of a Water-Based Lubricant from Lignocellulosic Biomass and Its Tribological Properties
Lignocellulosic biomass is considered
as a major feedstock to produce value-added renewable chemicals. In
this study, a new water-based lubricant was prepared using biomass-derived
levulinic acid (LA) and polyols such as ethylene glycol and glycerol.
The products were separated by rotary film molecular distillation
and characterized by <sup>1</sup>H NMR and mass spectrometry. Lubricant
properties such as kinematic viscosity, pour, cloud, and flash points,
copper strip corrosion, and volatility at 120 °C were evaluated
according to standard ASTM methods. Furthermore, the hydrolytic stability
and tribological properties of the products were tested for water-based
lubricants. The results indicated that glycerol ester of levulinic
acid (LAGLE) exhibited superior lubricant properties, strong resistance
to hydrolytic degradation, and excellent antiwear performance, implying
that the biomass-derived LAGLE was a potential water-based lubricant
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