Background: Passive or therapist-assisted stretching, followed by scapular stabilization exercises, has been shown to be effective. However, most previous studies have focused on stretching individual muscles or specific movement directions, often neglecting the role of active scapular stretching. Objects: This study aimed to compare changes in the muscle activity of the lower trapezius (LT), serratus anterior (SA), and upper trapezius (UT), as well as the scapular posterior tilt (SPT) angle before and after scapular circle (SC) stretching during SPT exercise. Methods: Twenty participants were recruited for this study. Electromyography electrodes were attached to the LT, SA, and UT. Muscle activity and the posterior scapular tilt angle were measured while performing the SPT exercises. After the SC stretch, the measurements were repeated in the same manner. The LT, SA, and UT electromyography activities and SPT angles were analyzed using paired t-tests. Results: LT activity was significantly higher in the SC stretch plus SPT exercise compared with in the SPT exercise alone (p = 0.018). There were no significant differences in SA activity between the SPT and SC stretch plus SPT exercise conditions (p = 0.812). UT activity significantly increased in the SC stretch plus SPT exercise compared with that in the SPT exercise (p = 0.001). The SPT angle was significantly enhanced during SPT exercise after the SC stretching compared to that without SC stretching (p = 0.009). The RSP improved by 2.32% compared to the initial posture when only the SPT was performed, and improved by 9.95% when the SPT was performed after the SC stretching. Conclusion: These results suggest that performing SC stretching prior to SPT exercise may effectively improve scapular alignment and posture, even when UT activation increases more than of the LT. Elevated UT activity highlights the need to address muscular balance in corrective exercise design.
Background: The purpose of this study was to compare gluteus medius (Gmed) and quadratus lumborum (QL) muscle activities and the Gmed/QL activity ratio, during five hip abduction exercises in individuals with Gmed weakness. Objects: Nineteen participants with clinically identified Gmed weakness performed five hip abduction exercises: side-lying hip abduction (SHA), side-bridge (SB), SB using sling (SB-sling), SB with hip abduction (SB-HA), and SB-HA using sling (SB-HA-sling). Surface electromyography recorded Gmed and QL, normalized to %maximum voluntary isometric contraction (%MVIC). A repeated-measures ANOVA was used to assess differences across conditions. Results: Significant differences were found in Gmed (F = 68.980, p = 0.001) and QL (F = 10.676, p = 0.001) activation across exercises. Gmed activity was highest in SB-HA (61.77 ± 14.46 %MVIC), while SHA produced the highest Gmed/QL activity ratio (1.70 ± 0.26), indicating more selective Gmed activation. SB and SB-sling showed lower Gmed activity and higher QL activation. SB-HA-sling resulted in moderate Gmed activation without significantly increasing QL activation. Conclusion: The SB-HA exercise is effective for co-activating Gmed and QL, while SHA and SB-HA-sling are better suited for selectively targeting Gmed with minimal QL compensation. These findings support exercise selection based on specific rehabilitation goals.
In the area of carbon-based thin films, graphene/polyimide conductive films display remarkable heat resistance and mechanical properties, making them a valuable resource for utilisation in a multitude of manufacturing and living contexts. Nevertheless, modulating the interfacial structure between graphene and polyimide represents a significant challenge in the pursuit of enhancing the conductivity of the composite films, due to the elevated initial temperature of polyimide pyrolysis (exceeding 600 °C). To develop it, this study found that polyimide could undergo chemical bond breaking and atomic rearrangement at around 500 °C, when subjected to an applied electric field in graphene/polyimide films. A series of characterisations showed that the graphene/polyimide film formed a new interfacial structure under electrothermal treatment, which enhanced the electron transport capacity and increased its conductivity from about 1497.01 s m− 1 to about 2688.17 s m− 1, with an increase of about 79.57%. This study would provide the possibility of modulating the structure of polyimide below the pyrolysis temperature, as well as a feasible idea for transferring the properties of graphene into the polyimide matrix.
Food contamination with heavy-metal ions and nitrites poses a serious threat to human health. Consequently, the development of fast and sensitive platforms for detecting these contaminants is urgently needed. In this study, a novel sensing platform was developed by integrating carbon nanotubes generated by the pyrolysis of waste masks (WMCNTs) with ZIF-8 for the simultaneous detection of Cd2+, Pb2+, and nitrite. Specifically, the electronic structure of the WMCNT backbone was modulated by doping with B and N atoms. Nanoporous ZIF-8 was then grown in-situ on its surface to produce composites with enhanced electrical conductivities and large specific surface areas. This modification provided more active sites for the attachment of heavy-metal ions and nitrites. Under optimized conditions, the sensing platform exhibited a wide linear range with the Pb2+, Cd2+, and NO2 − limits of detection of 2.68, 12.12, and 5.94 μM, respectively. Notably, the sensing platform demonstrated excellent anti-interference capabilities and effectively detected nitrites and heavy-metal ions in pickled foods.
본 연구는 중국상업은행을 대상으로 COVID-19로 인한 위기를 극복하는 과정에 긍정적인 영향 을 미친 변수가 무엇인지를 분석하였다. 이를 위해 분석표본을 대상으로 맘퀴스트지수 (Malmquist index) 생산성 분석을 실시하여 COVID-19 전후 생산성이 모두 양호했던과 모두 불량했던 그룹 으로 구분한 후, 각 그룹별로 패널 (panel) 분석을 수행하여 수익성 결정요인을 비교하였다. 주요 분석결과는 다음과 같다. COVID-19 전후 지속적으로 높은 생산성을 유지한 중국상업은행 은 자산건전성이 높을수록, 수지비율이 낮을수록, 규모가 작을수록 그리고 이자수익이 높을수록 수 익성에 긍정적인 영향을 발휘하여 COVID-19를 극복한 것으로 확인되었다. 이는 두 그룹 간 생산 성변화 차이가 은행의 경영자원 배분과 경영특성에 의한 것임을 시사한다. 향후 중국상업은행은 수 익구조 개선, 비즈니스 모델의 혁신, 디지털전환에 대한 적극 대응을 해나가야만 지속가능한 성장 을 도모할 수 있을 것이다.
Silicon carbide (β-SiC) was synthesized through an improved sol–gel method, then Ni/SiC catalysts were prepared using a hydrothermal method. The catalysts were characterized using TEM, H2- TPR, CO2- TPD and N2- TPD, etc. The results showed that the synthesized β-SiC had a large specific surface area, promoting the dispersion of Ni species and thus exposing more active sites. The interaction between Ni species and β-SiC contributed significantly to catalytic performance. Furthermore, the strong alkalinity of catalyst could adjust the bond energy of the active metal and N (M–N), which were conducive to desorption of the recombinant N2 from the metal surface, promoting to ammonia decomposition. Among the Ni/SiC catalysts, 30Ni/SiC-700 synthesized with the Ni loading of 30 wt% and calcination temperature of 700 °C, exhibited the optimal ammonia conversion rate of 93.4% at 600 °C under the space speed of 30,000 mL∙gcat −1∙h−1, and demonstrated a long-term stability, suggesting a very promising catalyst in ammonia decomposition.
Moso bamboo, as a kind of renewable functional material, exhibits outstanding development potential. It is promising to prepare activated carbon with good mechanical strength and high specific surface area using moso bamboo as raw material. In this work, we employed a hydraulic extruder to extrude the bamboo charcoal and the adhesive to obtain the moso bamboo activated carbon, and improved the specific surface area of the columnar activated carbon through high-temperature water vapor activation. Through the catalytic role of the water vapor activation process, the formation and expansion of the pores were promoted and the internal pores were greatly increased. The obtained columnar activated carbon shows excellent mechanical strength (93%) and high specific surface area (791.54 m2/ g). Polyacrylamide@asphalt is one of the most effective adhesives in the high-temperature water vapor activation. The average pore size (22.99 nm) and pore volume (0.36 cm3/ g) of the prepared columnar activated carbon showed a high mesoporous ratio (83%). Based on the excellent pore structure brought by the activation process, the adsorption capacity of iodine (1135.75 mg/g), methylene blue (230 mg/g) and carbon tetrachloride (64.03 mg/g) were greatly improved. The resultant moso bamboo columnar activated carbon with high specific surface area, excellent mechanical properties, and outstanding adsorption capacity possesses a wide range of industrial applications and environmental protection potential.
In this paper, iron ore tailings (IOT) were separated from the tailings field and used to prepare cement stabilized macadam (CSM) with porous basalt aggregate. First, the basic properties of the raw materials were studied. Porous basalt was replaced by IOT at ratios of 0, 20 %, 40 %, 60 %, 80 %, and 100 % as fine aggregate to prepare CSM, and the effects of different cement dosage (4 %, 5 %, 6 %) on CSM performance were also investigated. CSM’s durability and mechanical performance with ages of 7 d, 28 d, and 90 d were studied with the unconfined compression strength test, splitting tensile strength test, compressive modulus test and freeze-thaw test, respectively. The changes in Ca2+ content in CSM of different ages and different IOT ratios were analyzed by the ethylene diamine tetraacetic acid (EDTA) titration method, and the micro-morphology of CSM with different ages and different IOT replaced ratio were observed by scanning electron microscopy (SEM). It was found that with the same cement dosage, the strengths of the IOT-replaced CSM were weaker than that of the porous basalt aggregate at early stage, and the strength was highest at the replaced ratio of 60 %. With a cement dosage of 4 %, the unconfined compressive strength of CSM without IOT was increased by 6.78 % at ages from 28 d to 90 d, while the splitting tensile strength increased by 7.89 %. However, once the IOT replaced ratio reached 100 %, the values increased by about 76.24 % and 17.78 %, which was better than 0 % IOT. The CSM-IOT performed better than the porous basalt CSM at 90 d age. This means IOT can replace porous basalt fine aggregate as a pavement base.
Cu2+/polyacrylonitrile composite fibers were prepared by electrospinning, and then Cu/carbon nanofibers (denoted as Cu/ CNF-X; X = Cu content, 0, 3, or 5 wt%) were formed by calcining them. The effects of Cu2+ content and carbonization temperature on the conductivity and electrothermal conversion of Cu/CNF-X were investigated. The results revealed that the conductivity and electrothermal properties of Cu/CNF-X improve with the increase in the Cu2+ content and carbonization temperature. When the carbonization temperature was 800, 900, or 1000 °C, the conductivity of Cu/CNF-5 (0.08, 0.68, or 2.48 S/cm, respectively) increased to 1.6, 1.5, or 1.6 times that of Cu/CNF-0, respectively. The highest instantaneous surface temperatures of Cu/CNF-5 calcined at 800, 900, and 1000 °C (36, 145, and 270.2 °C, respectively) increased by 4, 25.5, and 44.6 °C, respectively, compared with those of the corresponding Cu/CNF-0 samples (32, 120.3, and 225.6 °C, respectively). Thus, the addition of a small amount of Cu2+ effectively improved the conductivity and electrothermal conversion performance of Cu/CNF-X, which has potential application value in industrial products in the future.