Effects of temperature cycles on human thermal comfort in built environment under summer conditions.

Dynamic temperature control strategies are feasible for enhancing energy flexibility and reducing energy consumption in buildings. However, guidelines for designing such dynamic thermal environments are lacking. In this study, 30 participants were recruited to undergo four experimental cycles formed by combining two temperature ranges (25-28 °C and 26-29 °C) and two temperature change rates (3 °C/h and 6 °C/h). Variations in the subjective perception and physiological responses with time were recorded throughout the experiments. The participants reported cooler thermal sensation and better thermal comfort for the same temperature during the ramp-down phase than during the ramp-up phase, which was more pronounced at faster temperature changes. The limits on temperature variations in the current standards underestimate the thermal acceptability of people. Although the temperature cycles exceeded the limits in the standards, sustained thermal comfort and high thermal acceptability were achieved when the temperature changed within 25-28 °C. At a rapid 6 °C/h change rate, the thermal sensation briefly deviated from the comfort zone when Top changed within 26-29 °C, suggesting that the limits should be set relative to the temperature change span. The comfortable temperature ranges for change rates of 3 °C/h and 6 °C/h in summer conditions were 22.8-28.7 °C and 22.8-28.4 °C, respectively, which are broader than the recommended indoor temperature range for summer in the Chinese standard. These findings indicate the potential of temperature variations to extend the thermal comfort zones while consuming less energy without requiring additional cooling devices.

Improvement of thermal perceptions and physiological responses using torso heating under short-term cold exposure.

Short-term cold exposure (<1 h) may adversely affect human thermal comfort and health. Few studies have investigated the effectiveness of body heating in providing thermal protection to the torso against sharp temperature decreases, as well as the optimal operation modes of torso heating equipment. In this study, 12 male subjects were acclimatised in a room at 20 °C, then exposed to a cold environment at -2.2 °C, and finally returned to the room for recovery; each phase lasted 30 min. During cold exposure, they wore uniform clothing with an electrically heated vest (EHV) operated under these modes: no heating (NH), stage-regulated heating (SH), and intermittent alternating heating (IAH). Variations in subjective perceptions, physiological responses, and temperatures set for heating were recorded during the experiments. Torso heating mitigated the adverse effects of the large temperature down-step and continuous cold exposure on thermal perception and decreased the occurrence of three symptoms: cold hands or feet, running or stuffy noses, and shivering during cold exposure. After torso heating, the same skin temperature of the non-directly heated parts corresponded to a higher local thermal sensation, which was attributed to an indirect effect of the improved overall thermal state. The IAH mode could achieve thermal comfort at a reduced energy level, and it outperformed SH in subjective perception enhancement and self-reported symptom relief at lower heating temperatures. Additionally, under the same heating setting temperatures and power capacity, it could achieve an approximately 50 % longer usage time than SH could. The results suggest that intermittent heating protocol can be an efficient way to achieve thermal comfort and energy savings for personal heating devices.

Incidence of lung cancer among healthcare workers in Hunan Province and analysis of related risk factors.

Background: The prevalence of lung cancer, a major type of malignant tumor, has been increasing over the years greatly impacting the health of Chinese residents. This study investigates the epidemiological characteristics of lung cancer among healthcare workers in the Hunan Province, as well as the occupational risk factors. Methods: The data analyzed in this study was collected from the largest tumor hospital in the province: the Hunan Provincial Tumor Hospital affiliated with Central South University, School of Medicine. The data collected encompasses input collected between the years of 2004 to 2013 of the population of healthcare workers who were hospitalized for lung cancer treatments. Information was obtained through statistical analysis and telephonic interviews. Results: The prevalence of lung cancer among healthcare workers was much higher than that of the general population, as revealed by the difference between number of healthcare worker cases per 1,000 cases and number of healthcare workers per 1,000 population in the decade from 2004 to 2013. Analysis of the data further demonstrates that lung cancer prevalence among healthcare workers increases exponentially with age. Although smoking has been shown to increase the incidence of lung cancer to some extent, it is most likely not the main cause of lung cancer. In addition, it appears that the highest rates of lung cancer incidence occurs in mainly in primary general practitioners, medical radiologists, and nurses. The lack of awareness of personal safety measures may place healthcare workers at a greater risk of lung cancer.

Neuroprotective Effects of Quercetin on Ischemic Stroke: A Literature Review.

Ischemic stroke (IS) is characterized by high recurrence and disability; however, its therapies are very limited. As one of the effective methods of treating acute attacks of IS, intravenous thrombolysis has a clear time window. Quercetin, a flavonoid widely found in vegetables and fruits, inhibits immune cells from secreting inflammatory cytokines, thereby reducing platelet aggregation and limiting inflammatory thrombosis. In pre-clinical studies, it has been shown to exhibit neuroprotective effects in patients with ischemic brain injury. However, its specific mechanism of action remains unknown. Therefore, this review aims to use published data to elucidate the potential value of quercetin in patients with ischemic brain injury. This article also reviews the plant sources, pharmacological effects, and metabolic processes of quercetin in vivo, thus focusing on its mechanism in inhibiting immune cell activation and inflammatory thrombosis as well as promoting neuroprotection against ischemic brain injury.

A Special Ancient Bronze Sword and Its Possible Manufacturing Technique from Materials Science Analysis.

In this study, it was found that an ancient bronze sword had special microstructures, i.e., a tin (Sn)-rich layer (Sn: 38.51 wt.%), that was around 0.1-0.3 mm in thickness in the bronze substrate (Sn: 18.57 wt.%). This sword was unearthed from the same Chu tombs of the "Sword of Gou Jian", and dated back to the late Spring and Autumn Period (496 BC-464 BC). The experimental and theoretical analyses revealed that (1) the Sn-rich layer exhibited higher microhardness (around 650 HV) than the sword body (around 300 HV); (2) the Sn-rich layer showed a brittle fracture due to the formation of a large amount of α + δ eutectoid, while the sword body was of good toughness due to a large amount of α-Cu solid solution phase; and (3) theoretical calculations of Sn diffusion in the Cu substrate indicated that this Sn-rich layer could have been formed within several hours or several days if the temperature was above 600 °C. Therefore, this sword was proposed to be a novel kind of composite bronze sword, and the possible manufacturing technique was a surface treatment called "dip or wipe tinning" or tin amalgam, which was widely used in the Bronze Age. Technically, this process possesses more advantages than the well-known two-times casting for making the "double-colour" or bi-metallic composite bronze sword. This research showed that the materials processing level was beyond our expectations for ancient China 2500 years ago.

Ultra-stretchable, super-hydrophobic and high-conductive composite for wearable strain sensors with high sensitivity.

With continuous development of artificial intelligence technology, strain sensors have attracted widespread attention. In this work, a novel high-performance wearable strain sensor is prepared by using a kind of ultra-stretchable, super-hydrophobic and high-conductive composite. The preparation process is as follows, i.e., using common elastic band (EB) as the polymer matrix, nano carbon black (CB) and carbon nanotubes (CNTs) as mixed conductive filler, and then modified by polydimethylsiloxane (PDMS) to obtain the PDMS/(CB + CNTs)/EB composite for assembling assemble flexible wearable strain sensors. Experimental results reveal the following excellent properties: 1) The composite exhibits excellent mechanical properties and super-hydrophobicity, i.e., the tensile strength is up to 996.5%, and the elastic modulus and tensile strength increase 49.2% and 59.2%, compared with pristine EB; 2) The composite strain sensor exhibits high sensitivity (the gauge factor reaches up to 648.83 under strain range of 979.9-996.5%), and it still shows stable performance after 3000 cycles tests (100% strain); 3) It is a well candidate to be used for monitoring human body motions including large and subtle body movements; 4) The composite sensor also has advantages of easy access of raw materials, simple preparation, easy mass production and relatively low production cost, showing a broad application prospect in wearable electronic products.

Graphene-Reinforced Zn-Ni Alloy Composite Coating on Iron Substrates by Pulsed Reverse Electrodeposition and Its High Corrosion Resistance.

In this paper, a novel kind of graphene (Gr)-reinforced Zn-Ni alloy composite coating is successfully prepared on an iron substrate by pulsed reverse electrodeposition. Hydrophilic graphene oxide (GO) is directly added to the electrolyte and reduced to Gr during coating. The experimental results reveal that (1) there is an optimal adding amount (about 0.4 g/L) of GO in the electrolyte for achieving the highest mechanical properties and corrosion resistance; (2) the composite coating shows grain refinement and a dense microstructure due to heterogeneous nucleation sites provided from the Gr sheets during electrodeposition; and (3) compared to the regular Zn-Ni coating, the composite coating exhibits many enhancements, including hardness increase by 2.3 times, elastic modulus increase by 39%, and corrosion rate decrease from 37.66 to 1.30 mils/annum. This process has advantages such as being simple, effective, well repeatable, economical, and supporting large-scale production and is expected to be widely applied in electronics, automobiles, marine engineering, and military industries.

"One-Step" Carbonization Activation of Garlic Seeds for Honeycomb-like Hierarchical Porous Carbon and Its High Supercapacitor Properties.

In this paper, a simple "one-step" route is introduced to prepare a kind of novel honeycomb-like hierarchical porous carbon (h-HPC) by carbonizing and activating garlic seeds. Due to its special microstructure, h-HPC shows excellent electrochemical properties and high supercapacitor performances. The experimental results reveal the following: (1) There exists an optimal condition for synthesizing h-HPC, i.e., 700 °C carbonization temperature and 1:1 mass ratio of KOH and garlic seeds. (2) h-HPC has a three-dimensional interconnected porous structure and exhibits a specific surface area as high as 1417 m2/g with a narrow pore size distribution. (3) When h-HPC is employed as an electrode material in supercapacitors, its specific capacitance reaches a value up to 268 F/g at a current density of 0.5 A/g and excellent rate capability. (4) The h-HPC-based symmetric supercapacitor shows a high energy density of 31.7 Wh/kg at a power density of 500 W/kg and retains 99.2% of the initial capacitance after 10,000 charge/discharge cycles at 200 mV/s. When compared with similar works, these data are competitive, which demonstrates that the garlic-derived h-HPC is a kind of promising electrode material for the next-generation high-energy-density supercapacitors.