Identification and Analysis of Small Interfering RNAs Associated With Heat Stress in Flowering Chinese Cabbage Using High-Throughput Sequencing

Endogenous small interfering RNAs (siRNAs) are substantial gene regulators in eukaryotes and play key functions in plant development and stress tolerance. Among environmental factors, heat is serious abiotic stress that severely influences the productivity and quality of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee). However, how siRNAs are involved in regulating gene expression during heat stress is not fully understood in flowering Chinese cabbage. Combining bioinformatical and next-generation sequencing approaches, we identified heat-responsive siRNAs in four small RNA libraries of flowering Chinese cabbage using leaves collected at 0, 1, 6, and 12 h after a 38°C heat-stress treatment; 536, 816, and 829 siRNAs exhibited substantial differential expression at 1, 6, and 12 h, respectively. Seventy-five upregulated and 69 downregulated differentially expressed siRNAs (DE-siRNAs) were common for the three time points of heat stress. We identified 795 target genes of DE-siRNAs, including serine/threonine-protein kinase SRK2I, CTR1-like, disease resistance protein RML1A-like, and RPP1, which may play a role in regulating heat tolerance. Gene ontology showed that predictive targets of DE-siRNAs may have key roles in the positive regulation of biological processes, organismal processes, responses to temperature stimulus, signaling, and growth and development. These novel results contribute to further understanding how siRNAs modulate the expression of their target genes to control heat tolerance in flowering Chinese cabbage.

Analysis of Hot-Cold Confusion on Fingers

The thermosensory system may misidentify a temperature stimulus with different thermal properties. The mechanism of this hot-cold confusion has not been clarified; hence, it has not yet been applied. In this study, we created a wearable temperature presentation device that is closer to the application and analyzed the tendency and mechanism of temperature confusion by analyzing the hot-cold confusion of temperature sensation in the fingers, which are most frequently in contact with objects. Two experiments were performed. In the first experiment, we presented stimuli on the tips of three fingers (first, second, and third fingers). In the second experiment, we presented stimuli at the center of the distal phalanx, middle phalanx, and proximal phalanx of the first finger. The experimental results indicated the occurrence of hot-cold confusion. Domination, in which the center is dominated by both ends, and a mutual effect, in which the center interacts with both ends, were observed.

Perception of Thermal Comfort during Skin Cooling and Heating

Due to the static and dynamic activity of the skin temperature sensors, the cutaneous thermal afferent information is dependent on the rate and direction of the temperature change, which would suggest different perceptions of temperature and of thermal comfort during skin heating and cooling. This hypothesis was tested in the present study. Subjects (N = 12; 6 females and 6 males) donned a water-perfused suit (WPS) in which the temperature was varied in a saw-tooth manner in the range from 27 to 42 °C. The rate of change of temperature of the water perfusing the suit (TWPS) was 1.2 °C min−1 during both the heating and cooling phases. The trial was repeated thrice, with subjects reporting their perception of the temperature and thermal comfort at each 3 °C change in TWPS. In addition, subjects were instructed to report when they perceived TWPS uncomfortably cool and warm during cooling and heating, respectively. Subjects reproducibly identified the boundaries of their Thermal Comfort Zone (TCZ), defined as the lower (Tlow) and upper (Thigh) temperatures at which subjects reported slight thermal discomfort. During the heating phase, Tlow and Thigh were 30.0 ± 1.5 °C and 35.1 ± 2.9 °C, respectively. During the cooling phase, the boundary temperatures of Tlow and Thigh were 35.4 ± 1.9 °C and 38.7 ± 2.3 °C, respectively. The direction of the change in the cutaneous temperature stimulus affects the boundaries of the TCZ, such that they are higher during cooling and lower during heating. These findings are explained on the basis of the neurophysiology of thermal perception. From an applied perspective, the most important observation of the present study was the strong correlation between the perception of thermal comfort and the behavioral regulation of thermal comfort. Although it is not surprising that the action of regulating thermal comfort is aligned with its perception, this link has not been proven for humans in previous studies. The results therefore provide a sound basis to consider ratings of thermal comfort as reflecting behavioral actions to achieve the sensation of thermal neutrality.

Covalent organic framework nanofluidic membrane as a platform for highly sensitive bionic thermosensation

Thermal sensation, which is the conversion of a temperature stimulus into a biological response, is the basis of the fundamental physiological processes that occur ubiquitously in all organisms from bacteria to mammals. Significant efforts have been devoted to fabricating artificial membranes that can mimic the delicate functions of nature; however, the design of a bionic thermometer remains in its infancy. Herein, we report a nanofluidic membrane based on an ionic covalent organic framework (COF) that is capable of intelligently monitoring temperature variations and expressing it in the form of continuous potential differences. The high density of the charged sites present in the sub-nanochannels renders superior permselectivity to the resulting nanofluidic system, leading to a high thermosensation sensitivity of 1.27 mV K−1, thereby outperforming any known natural system. The potential applicability of the developed system is illustrated by its excellent tolerance toward a broad range of salt concentrations, wide working temperatures, synchronous response to temperature stimulation, and long-term ultrastability. Therefore, our study pioneers a way to explore COFs for mimicking the sophisticated signaling system observed in the nature.

ICG/5-Fu coencapsulated temperature stimulus response nanogel drug delivery platform for chemo-photothermal/photodynamic synergetic therapy

The multiple diagnosis and treatment mechanisms of chemotherapy combined with photothermal/photodynamic therapy have very large application prospects in the field of cancer treatment. Therefore, in order to achieve effective and safe antitumour treatment, it is necessary to design an intelligent responsive polymer nanoplatform as a drug delivery system. Herein, the thermosensitive poly-N-isopropylacrylamide (PNIPAM) nanogel particles were prepared by soap-free emulsion polymerization and loaded with a large amount of photosensitizer indocyanine green (ICG) and anticarcinogen 5-fluorouracil (5-Fu), which effectively to realize the cooperative chemotherapy and photothermal/photodynamic therapy for tumours. The 5-Fu@ICG-PNIPAM nanogels significantly improved the bioavailability of the drug and achieved controlled release. In addition, under near-infrared laser (NIR) irradiation at 808 nm, 5-Fu@ICG-PNIPAM nanogels generated lots of heat and reactive oxygen, which significantly enhanced cellular uptake and in vitro antitumour treatment effects. The results showed that 5-Fu@ICG-PNIPAM nanogels were effectively endocytosed by HeLa cells, which also enhanced the drug’s entrance into the nucleus. Moreover, compared with alone chemotherapy or photothermal/photodynamic therapy, 5-Fu@ICG-PNIPAM nanogels significantly increased cytotoxicity under NIR irradiation, suggesting that chemotherapy and photothermal/photodynamic synergistic therapy had excellent antitumour properties. Therefore, this temperature-responsive nanogel platform probably has great application prospects in clinical antitumour treatment.

Hierarchically patterned self-powered sensors for multifunctional tactile sensing

Flexible sensors are highly desirable for tactile sensing and wearable devices. Previous researches of smart elements have focused on flexible pressure or temperature sensors. However, realizing material identification remains a challenge. Here, we report a multifunctional sensor composed of hydrophobic films and graphene/polydimethylsiloxane sponges. By engineering and optimizing sponges, the fabricated sensor exhibits a high-pressure sensitivity of >15.22 per kilopascal, a fast response time of <74 millisecond, and a high stability over >3000 cycles. In the case of temperature stimulus, the sensor exhibits a temperature-sensing resolution of 1 kelvin via the thermoelectric effect. The sensor can generate output voltage signals after physical contact with different flat materials based on contact-induced electrification. The corresponding signals can be, in turn, used to infer material properties. This multifunctional sensor is excellent in its low cost and material identification, which provides a design concept for meeting the challenges in functional electronics.

Temperature-triggered attachment and detachment of general human bio-foulants on zwitterionic polydimethylsiloxane

Biofouling control via attachment and detachment of the different biofoulants through a temperature stimulus. This was achieved by coating polydimethylsiloxane with a copolymer having both bioinert and temperature responsive segments.