Hasil untuk "Chemistry"

J. Loudon

W. Woolcock

K. Moller, T. Bein

U. Zielke, K. J. Hüttinger, W. Hoffman

T. Mason

A. Horowitz

M. Rees

Satoru Hayami

We theoretically investigate the influence of uniaxial distortion on the stability of square skyrmion crystals, which are described as double-<i>Q</i> spin textures composed of two orthogonal spiral modulations, in noncentrosymmetric magnets. An effective spin model incorporating momentum-resolved frustrated exchange interactions and Dzyaloshinskii–Moriya (DM) interactions is analyzed using simulated-annealing calculations at low temperatures. The results reveal that uniaxial distortion drives a transformation from the double-<i>Q</i> square skyrmion crystal to a single-<i>Q</i> tilted conical spiral or vertical spiral state. The low-temperature phase diagrams further show that the stability region of the skyrmion crystal expands with increasing the magnitude of the DM interaction, making the phase more robust against the uniaxial anisotropy between exchange interactions parallel and perpendicular to the distortion axis. This study provides insight into how uniaxial strain and DM interactions cooperatively influence the formation and stability of skyrmion crystal phases in noncentrosymmetric magnetic systems.

P. Luppa, L. Sokoll, Daniel W. Chan

J. Sessler, D. Seidel

L. Sayre, M. Smith, George Perry

Xiu-An Ye, Shu-Hong Lin, Liang-Yu Chen et al.

Pulmonary tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), necessitates early diagnosis for effective patient care. Despite advancements in TB diagnostics, there remains an urgent need to discover innovative non-sputum-based methods to detect Mtb-specific antigens for TB patient identification. We have developed a polymer-based electrochemical biosensor for detecting an Mtb-specific antigen, the 6-kDa early secreted antigenic target (ESAT-6), in blood. Using a gold electrode (Au), the biosensor is created by electropolymerizing poly(3,4-ethylene dioxythiophene) with carboxyl groups (PEDOT-COOH), which is activated with 3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide (EDC-NHS), conjugated with an ESAT-6 polyclonal antibody (Ab), treated with bovine serum albumin (BSA) to block non-specific binding, forming BSA/Ab-EDC-NHS/PEDOT-COOH/Au. Using differential pulse voltammetry measurements, the electrode demonstrated an excellent linear response (R2 = 0.99) for ESAT-6 detection across a concentration range of 24.2 pM (0.81 ng/mL) to 50 nM (1.69 μg/mL), with a low detection limit of 1.39 pM (0.047 ng/mL) and a rapid detection time of under 4 min. This biosensor for ESAT-6 detection effectively distinguished pulmonary TB patients from healthy individuals, achieving 95.0 % sensitivity and 100 % specificity at a cut-off value of 97.0 ng/mL. It demonstrated a diagnostic accuracy of 97.1 %, outperforming the 82.9 % achieved by a commercial ELISA kit. Moreover, biosensor-detected ESAT-6 levels were significantly higher in smear-positive TB patients compared to the smear-negative group (p = 0.014), whereas ELISA-based detection showed no significant difference (p = 0.197). In conclusion, the PEDOT-COOH biosensor enables rapid and effective detection of plasma ESAT-6, facilitates TB diagnosis, and correlates with Mtb bacterial burden, highlighting its potential for disease monitoring.

Daisuke Shimoyama, Shunsuke Sato, Shunta Ohsawa et al.

Ncamisile Nondumiso Maseko, Dirk Enke, Pius Adewale Owolawi et al.

Qijia Mao, Fuan Hua, Zhuohuang Wu et al.

This study introduces a novel vertical bending continuous casting technology for producing thin slabs of pure aluminum and aluminum alloys, offering significant advancements over traditional vertical casting methods. The newly designed equipment and optimized process parameters enable the continuous casting of pure aluminum 1070 at a speed of 1.2 m/min, surpassing the casting speed of conventional direct-chill casting. Comprehensive investigations of the macrostructure and microstructure of the cast pure aluminum 1070 reveal a refined equiaxed crystal structure with an average grain size of 98 μm, significantly smaller than that obtained through conventional casting processes. This refinement in grain size is expected to enhance the material’s mechanical properties and processing capabilities. Additionally, simulations of the temperature distribution and solidification structure provide insights into the formation of a “U”-shaped sump and liquidus isotherms, which are crucial for understanding the solidification dynamics of the material. The refined grain structure and increased casting speed demonstrate substantial potential for advancing aluminum alloy production, especially in applications requiring superior performance and more efficient manufacturing processes.

Nguyen Bui Tam Nhu, Ho Phuong, Nguyen Ngoc Que Anh et al.

J. Gladysz, D. Curran, I. Horváth

R. Green, S. Flamm

James H. Clark

Zhongxue Tang, Kang Luan, Bojie Xu et al.

Unidirectional liquid transport (UDLT) has been widely used in various fields as an important process for transferring both mass and energy. However, UDLT driven by a structural gradient has been witnessed for a long time only in wettable liquids. For nonwettable liquids, UDLT can hardly proceed merely by a structural gradient. Herein, we propose an asymmetrically concave structured surface (AMC-surface), featuring tip-to-base periodically arranged pyramid-shaped concave structures with a certain degree of overlap, which enables the UDLT of both wettable and nonwettable liquids. For wettable liquids, the capillary force along each corner leads to the UDLT pointing toward the base side of the concave pyramid, while for nonwettable liquids, the UDLT is attributable to the static liquid pressure overwhelming the repulsive Laplace pressure induced by the asymmetric grooves and overlapping part. As a result, both wettable and nonwettable liquids transport spontaneously and unidirectionally on the AMC-surface with no energy input. Moreover, the concave structure endows good mechanical stability and can be easily prepared using a facile nail-punching approach over a large area. We also demonstrated its application in a continuous chemical reaction in a confined area. We envision that the unique UDLT behavior on the as-developed AMC-surface will shed new light on the programmable manipulation of various liquids.