Results in Chemistry
·
2023
·
IF 2.3
Le Wang
Objective To establish a headspace gas chromatography method to determine the residual solvents of methanol, acetone, dichloromethane, and toluene in cefepime. Methods Headspace gas chromatography using a DB-624 capillary column and temperature program was performed to detect four residual solvents in cefepime. The temperature program consisted of an initial temperature of 60 ℃maintained for 4 min, a temperature increased to 120 ℃ at 20 ℃·min −1 maintained for 3 min, and then a temperature increased to 200 ℃ at 40 ℃·min −1 maintained for 3 min. Results Linear relationships were found between the peak areas and mass concentrations of the four solvents mentioned above within the defined ranges. The limits of detection for methanol, acetone, dichloromethane and toluene were 0.50, 0.15, 0.10 and 0.08 mg·L -1 , respectively. The recoveries obtained using the standard addition method ranged from 98.41 % to 100.94 %. Conclusion This method demonstrated high sensitivity and good reproducibility, and it can be used to effectively control the residual amounts of methanol, acetone, dichloromethane, and toluene, to further improve the quality of cefepime.
研究领域:
分析化学
·
药物分析
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Space: Science & Technology
·
2026
·
IF 6.4
Chuanyang Jiang,Zhaopeng Chen,Bin Luo,Sheng Yang,Zhengwei You,Wenchang Tan,Hao Huang,Jiao Yu,Lu Cao
As an emerging soft functional material, poly(glycerol sebacate) (PGS) has found substantial applications across a broad spectrum of engineering practices. This study reports the preparation of porous PGS materials with negative Poisson’s ratios through polycondensation and the salt-leaching method. The microscopic pore structures and dynamic mechanical properties of these PGS materials with negative Poisson’s ratios are quantitatively characterized by using scanning electron microscopy and a dynamic mechanical analyzer. These quantitative characterizations will provide technical support and innovative perspectives for the design of novel materials in aerospace engineering, as well as for the development of eco-friendly and flexible applications.
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Space: Science & Technology
·
2026
·
IF 6.4
Chenmin Liu,Mingke Wu,Wenkai Shao,Chenlong Duan,Honglun Yang,Zongxu Yao,Tianqi Xu,Ruilin Li,Liang Dong
C-type asteroids are key targets for In-Situ Resource Utilization (ISRU) in thebackground of space mining. As a component of ISRU, space mineral processing playsa crucial role by cutting transportation costs while facilitating subsequent resourceextraction. However, relevant studies are hindered by limited asteroid samples andpoorly constrained physical parameters of asteroid regolith. To address this gap, thisstudy presents a novel methodology for preparing a high-fidelity asteroid regolithsimulant (ARS) using a synthetic process which mimics the formation history of C-typeasteroids. A C-type Asteroid Regolith Simulant (namely CARS-1) has been developedbased on compositional data from Ryugu samples returned by the Hayabusa2 mission.Characterization results reveal the proposed simulant displays a close agreement inelemental composition, bulk density, porosity, particle size distribution, and spectralreflectance. Based on testing results of the CARS-1, we further estimate the compressivestrength of Ryugu rocks to be around 40 MPa and the angle of repose of Ryugu regolithparticles to be 30-36°. The Ryugu regolith may exhibit moderately weak magnetizationscaling inversely with temperature. Finally, the feasibility of applying in-situ mineralprocessing technology on the surface of C-type asteroids is assessed, and severalrecommended processing strategies are proposed. This study has shed new light on thepreparation of high-fidelity ARSs and provided reliable testing materials for thedevelopment of space mineral processing
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2024
·
IF 5.3
Yue Cai,Xinrui Zhang,Wentao Hu,Fuhang Song,Hong Wang,Huawei Zhang,Xuanrong Sun
Transdermal drug delivery represents a promising avenue for the treatment of dermatologic diseases, such as cutaneous melanoma and skin infections. This study involves the development of a novel therapeutic strategy that employs a skin-penetrating peptide SPACE-modified flexible liposomal chrysomycin A (CA@SPACE-LP) with a particle size of 111.5 nm. In vitro transdermal experiments demonstrated that CA@SPACE-LP was effective in enhancing the ability of the drug to penetrate the stratum corneum and enter deep into the skin tissue, increasing the intradermal drug concentration up to threefold compared to free CA. Furthermore, CA@SPACE-LP was observed to maintain the biological activity of CA against planktonic Methicillin-resistant Staphylococcus aureus (MRSA) and melanoma cells. In vivo studies demonstrated that the topical administration of CA@SPACE-LP was efficacious in controlling the progression of cutaneous melanoma, with a tumor suppression rate of approximately 60 %, which was more pronounced than that observed with intravenous Taxol. Furthermore, CA@SPACE-LP demonstrated efficacy in the management of intradermal MRSA infections, with a significantly reduced area of ulceration in the treated mice (0.25 cm 2 ) compared to the positive control drug (Mupirocin Ointment). These results suggest that the topical delivery system developed in this study has the potential to be used for the simultaneous treatment of skin cancer and invasive MRSA infection.
研究领域:
药剂学
·
皮肤病学
·
肿瘤学
·
微生物学
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DOI
PubMed
高影响因子
ENERGY AND BUILDINGS
·
2001
·Vol. 34
·期 4
·311-319
·
IF 0.368
Jamal O Jaber
This paper presents some insight to the problem of heating of housing in Jordan. Residential space and water heating are dependent particularly upon the combustion of fossil fuels, which thereby contribute significantly to air pollution and the build-up of carbon dioxide in the atmosphere. The results of a recent survey were used to evaluate the energy demand and conservation in Jordanian residential buildings. Space heating accounts for 61% of the total residential energy consumption with kerosene being the most popular fuel used, followed by liquefied petroleum gas (LPG), for heating purposes. Unvented combustion appliances employed to provide space heating produce high levels of combustion by-products that often exceed acceptable concentrations, degraded indoor air quality and cause unnecessary exposure to toxic gases such as carbon monoxide. During 1999, the number of accidents in households due to the use of different energy forms accounted for about 40% of all accidents, except road accidents, in Jordan. In light of the fact that only 5% of dwellings in Jordan have been provided with wall insulation and none employ roof insulation, the overall heat transfer coefficients, and consequently heating loads, were estimated for a typical single house using different constructions for external walls. It is concluded that space heating load can be reduced by about 50%, when economically-viable insulating measures are applied to the building envelopes, i.e. to ceilings and walls. These lead to corresponding reductions in fossil fuels consumption and in emissions of air pollutants.
研究领域:
能源效率
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建筑科学
·
室内空气质量
·
环境工程
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DOI
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Nature Photonics
·
2024
·Vol. 18
·期 11
·1185-1194
·
IF 32.3
Xu Qingyang,Zhang Jianyu,Sun Jing Zhi,Zhang Haoke,Tang Ben Zhong
Manipulating the electronic structure of organic functional materials by through-space conjugation (TSC) to achieve desirable photophysical properties has been a long-standing research focus. Although the working mechanisms of TSC have been demonstrated, the roles that the intrinsic molecular skeleton and extrinsic aggregates play remain unclear. Here four trinaphthylmethanol isomers and four trinaphthylmethane (TNM) isomers with varying connecting sites of naphthalene were synthesized, and their photophysical properties were systematically investigated. The strength of TSC was found to rise from 222-TNM to 111-TNM with the increased number of 1-naphthalene units. In particular, 111-TNM was found to support efficient long-wavelength clusteroluminescence with an absolute quantum yield of 55%. Experimental and theoretical results revealed that the inherent attribute of robust intramolecular interactions within individual molecules is fundamental for ultrastrong TSC, and intermolecular interactions play an auxiliary role in fortifying and stabilizing intramolecular interactions. This work reveals the intrinsic and extrinsic factors for manipulating TSC and provides a reliable strategy for constructing non-conjugated luminogens with efficient clusteroluminescence.
研究领域:
有机化学
·
材料科学
·
光化学
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DOI
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INHALATION TOXICOLOGY
·
2008
·
IF 1.831
Mansoor Keyanpour-Rad
The aim of this study was to investigate qualitatively the emission of toxic organic pollutants
from an unventilated conventional kerosene space heater commonly used in Iran. A brand new
common convective kerosene space heater, the "Aladdin," was used for this study. The welltuned
convective heater was operated in a 2.6-m3 test chamber and then the emission was tested
for organic pollutants. The emission was collected on Teflon-impregnated glass-fiber filters and
XAD-2 resin and then analyzed by gas chromatographymass spectroscopy. It was found that
in addition to the ordinary pollutant gases, the heater emits aliphatic hydrocarbons, alcohols,
polyaromatic hydrocarbons and the related nitrated compounds, phthalates, naphthalenes,
and some other toxic organic compounds. However, it was found that the heater did not emit
fluoranthene, cyclohexane, benzoic acid, and higher-molecular-weight alkylbenzenes, which
could have resulted from the combustion of some other types of kerosene.
研究领域:
环境科学
·
室内空气质量
·
污染化学
·
燃烧排放
·
毒理学
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高影响因子
Nature Communications
·
2022
·Vol. 13
·期 1
·1-8
·
IF 17.694
Liu Xiao,Wu Jingping,Qiao Keke,Liu Guohan,Wang Zhengjin,Lu Tongqing,Suo Zhigang,Hu Jian
Many living tissues achieve functions through architected constituents with strong adhesion. An Achilles tendon, for example, transmits force, elastically and repeatedly, from a muscle to a bone through staggered alignment of stiff collagen fibrils in a soft proteoglycan matrix. The collagen fibrils align orderly and adhere to the proteoglycan strongly. However, synthesizing architected materials with strong adhesion has been challenging. Here we fabricate architected polymer networks by sequential polymerization and photolithography, and attain adherent interface by topological entanglement. We fabricate tendon-inspired hydrogels by embedding hard blocks in topological entanglement with a soft matrix. The staggered architecture and strong adhesion enable high elastic limit strain and high toughness simultaneously. This combination of attributes is commonly desired in applications, but rarely achieved in synthetic materials. We further demonstrate architected polymer networks of various geometric patterns and material combinations to show the potential for expanding the space of material properties.
研究领域:
材料科学
·
生物医学工程
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Changzhen Wang,Xiangyu Jie,Yuan Qiu,Yongxiang Zhao,Hamid A. Al-Megren,Saeed Alshihri,Peter P. Edwards,Tiancun Xiao
Metal sintering and carbon deposition are acknowledged to be the foremost critical issues in the important energy storage process of high temperature Dry Reforming of Methane (DRM). For that process, so-called “core-shell catalysts” have exhibited outstanding catalytic performance. However, the intrinsic confined geometric space of the host core-shell structure not only inevitably limits the ability of the catalyst system to facilitate the critical rapid infusion and diffusion of reacting gases, but also enhances the accompanying conversion of carbon intermediates to inert, catalyst-deactivating carbonaceous deposits under high-space-velocity conditions. Herein, we present a study highlighting the importance of the inner cavity space, now of a quasi-zero-dimensional, tubular, yolk-shell structured Ni@SiO 2 nanocapsule catalyst, in the DRM process. The tubular yolk-shell structured Ni@SiO 2 nanocapsule catalysts having controlled inner cavities (5.0–13.0 nm × 5.0–50.0 nm dimensions) were synthesised via a water-in-oil micro-emulsion method by employing different aging times (i.e. 3 h, 6 h and 12 h). Compared with corresponding Ni@SiO 2 nanosphere catalysts, the tubular nanocapsule catalysts displayed both excellent catalyst activity, stability, and (metal) anti-sintering ability with, equally important, negligible carbon deposition during the operating DRM process under high space velocity conditions (60 L g −1 h −1 ), most relevant for application in real industrial processes.
研究领域:
催化化学
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材料科学
·
能源化学
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高影响因子
NEURON
·
2024
·
IF 14.7
Shijie Chen,Ning Cheng,Xiaojing Chen,Cheng Wang
Episodic memory is organized in both spatial and temporal contexts. The hippocampus is crucial for episodic memory and has been demonstrated to encode spatial and temporal information. However, how the representations of space and time interact in the hippocampal memory system is still unclear. Here, we recorded the activity of hippocampal CA1 neurons in mice in a variety of one-dimensional navigation tasks while systematically varying the speed of the animals. For all tasks, we found neurons simultaneously represented space and elapsed time. There was a negative correlation between the preferred space and lap duration, e.g., the preferred spatial position shifted more toward the origin when the lap duration became longer. A similar relationship between the preferred time and traveled distance was also observed. The results strongly suggest a competitive and integrated representation of space-time by single hippocampal neurons, which may provide the neural basis for spatiotemporal contexts.
研究领域:
神经科学
·
认知科学
·
行为神经科学
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhipeng Ni,Haiying Zhou,Haojie Yu,Li Wang,Chenguang Ouyang,Jian Yang,Yanzhao Dong,Ahmad Alhaskawi,Tian Tu,Hui Lu
The bidirectional regulations of antiadhesion and regeneration are crucial for Achilles tendon injuries. However, the precise prevention and treatments of peritendinous adhesions both in time and space are still great challenges. Here, a series of time–space regulating prodrug (tannic acid (TA), epigallocatechin (EGC) and epigallocatechin gallate (EGCG)) hydrogels are designed for the prevention of peritendinous adhesion in Achilles tendon contusion and rupture injuries. In the term of space, the self-healing and deformable hydrogels prepared by crosslinking phenylboric acid (PBA) functionalized polyphosphazene (PZBA) with guar gum (GG) through ROS-responsive phenylborate ester (PBAE) can specifically aggregate to the high ROS sites via the ROS-responsive degradation and recombination of PBAE. Thus, providing support and acting as barriers to inhibit fibroblast proliferation. In the term of time, the prodrug strategy using ROS-responsive PBAE as bridging linker can achieve long-term anti-inflammatory effect over 2 weeks. Furthermore, the degradation time of hydrogels matched the course of peritendinous adhesion, thus achieved bidirectional regulations (decrease the gene expression of TGF-β1, COL-1 and COL-3 to antiadhesion in the early stage but increase them to promote regeneration in the late stage). This study presents a promising approach employing smart prodrug hydrogels with time–space regulating properties for prevention of peritendinous adhesion.
研究领域:
生物医学工程
·
药剂学
·
材料科学
·
组织工程
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DOI
高影响因子
Nature Communications
·
2026
·
IF 15.7
Xu Qingyang,Luo Kangwei,Wang Yipu,Wu Jiajie,Lu Hongwei,Chen Manyu,Xiong Zuping,Sun Jing Zhi,Zhang Jianyu,Huang Feihe,Tang Ben Zhong,Zhang Haoke
Multi-axis atropisomers are ubiquitous in nature, and their intricate stereoconformations not only deepen stereochemical understanding but also elucidate fundamental principles of molecular atropisomeric dynamics. Nevertheless, insights into multi-axis atropisomerism remain limited. This work presents a systematic investigation of three classes of LaPlente-type biaxial atropisomers based on naphthalene rotors and phenyl linkers. Thermodynamically and kinetically controlled interconversion of molecular conformations is achieved in 22-NB, 11-NB, and 11-NB-8DMe. Concurrently, a direct correlation between molecular dynamics and electronic through-space conjugation (TSC) is elucidated. Furthermore, absolute separation of syn and anti conformers is accomplished in 11-NB-2DMe, whose distinct TSC-induced fluorescence enables direct visualization of dynamic conformer populations and kinetics during temporally sequential crystallization. This work provides fundamental mechanistic insights into multi-axis atropisomer stereochemistry and establishes a fluorescence-based approach as an in-situ platform for real-time analysis of molecular dynamics across life and materials sciences.
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