Change in glomalin-related soil protein along latitudinal gradient encompassing subtropical and temperate blue carbon zones.

Glomalin-related soil protein (GRSP), an abundant and eco-friendly bioproduct associated with arbuscular mycorrhizal fungi (AMF), contributes significantly to the soil particle aggregation and carbon sequestration. Although much research has been conducted on the storage of GRSP at different spatio-temporal scales in terrestrial ecosystems. However, the deposition of GRSP in large-scale coastal environments has not been revealed, which hinders an in-depth understanding of GRSP storage patterns and environmental controls, and this knowledge gap has become one of the key uncertainties in understanding the ecological functions of GRSP as blue carbon components in coastal environments. Therefore, we conducted large-scale experiments (spanning subtropical and warm temperate climate zones, coastlines over 2500 km) to test the relative contributions of environmental drivers that shape unique GRSP storage. In salt marshes of China, we found that the abundance of GRSP ranges from 0.29 mg g-1 to 1.10 mg g-1, and its concentration decreases with increasing latitude (R2 = 0.30, p < 0.01). The GRSP-C/SOC of salt marshes ranged from 4 % to 43 % and increased with the increase in latitude (R2 = 0.13, p < 0.05). The carbon contribution of GRSP does not follow the trend of increasing abundance, but is limited by the total amount of background organic carbon. In salt marsh wetlands, precipitation, clay content and pH are the main factors influencing GRSP storage. GRSP is positively correlated with precipitation (R2 = 0.42, p < 0.01) and clay content (R2 = 0.59, p < 0.01), but negatively correlated with pH (R2 = 0.48, p < 0.01). The relative contributions of the main factors to the GRSP differed across climatic zones. Soil properties, such as clay content and pH, explained 19.8 % of the GRSP in subtropical salt marshes (20°N < 34°N), however, in warm temperate salt marshes (34°N < 40°N), precipitation explained 18.9 % of the GRSP variation. Our study provides insight into the distribution and function of GRSP in coastal environments.

Mid- and long-wave infrared point spectrometer (MLPS): a miniature space-borne science instrument.

The mid- and long-wave infrared point spectrometer (MLPS) is an infrared point spectrometer that utilizes unique technologies to meet the spectral coverage, spectral sampling, and field-of-view (FOV) requirements of many future space-borne missions in a small volume with modest power consumption. MLPS simultaneously acquires high resolution mid-wave infrared (∼2-4 µm) and long-wave infrared (∼5.5-11 µm) measurements from a single, integrated instrument. The broadband response of MLPS can measure spectroscopically resolved reflected and thermally emitted radiation from a wide range of targets and return compositional, mineralogic, and thermophysical science from a single data set. We have built a prototype MLPS and performed end-to-end testing under vacuum showing that the measured spectral response and the signal-to-noise ratio (SNR) for both the mid-wave infrared (MIR) and long-wave infrared (LIR) channels of MLPS agree with established instrument models.

Up-regulation of circARF3 reduces blood-brain barrier damage in rat subarachnoid hemorrhage model via miR-31-5p/MyD88/NF-κB axis.

Inflammation events have been found to aggravate brain injury and blood-brain barrier (BBB) damage following subarachnoid hemorrhage (SAH). This study probed the role and mechanism of a novel circRNA, circARF3, in regulating the BBB injury in SAH rats and hypoxia-induced vascular endothelial cell (VEC) injury in vitro. Levels of circARF3 and miR-31-5p were monitored by RT-PCR. The expression of inflammatory factors IL-1ß and TNF-α was verified by ELISA. In vivo SAH model was constructed in Sprague Dawley (SD) rats. The BBB integrity and cerebral edema, as well as the neurological functions of the rats were evaluated. The apoptotic neurons and microglia in brain lesions were examined by immunohistochemistry (IHC). The MyD88/NF-κB pathway was tested by Western blot. Furthermore, gain-of functional assay were constructed to explore the effects of circARF3 and miR-31-5p in primary cultured brain microvascular endothelial cell (BMEC) injury and microglial inflammation induced by oxygen and glucose deprivation (OGD). circARF3 was significantly down-regulated in plasma and CSF in SAH patients with higher Fisher stages. In the SAH rat model, overexpressing circARF3 improved BBB integrity and neurological score, decreased neuronal apoptosis and microglial activation in ipsilateral basal cortex, with declined miR-31-5p expression and MyD88-NF-κB activation. In vitro, overexpressing circARF3 attenuated OGD-mediated integrity destruction of BMECs and microglial induced neuroinflammation, while overexpressing miR-31-5p had opposite effects. Mechanistically, circARF3 sponged miR-31-5p as an endogenous competitive RNA and dampens its expression, thus inactivating MyD88-NF-κB pathway. CircARF3 attenuates BBB destruction in SAH rats by regulating the miR-31-5p-activated MyD88-NF-κB pathway.

Temperature-Dependent Mean Free Path Spectra of Thermal Phonons Along the c-Axis of Graphite.

Heat conduction in graphite has been studied for decades because of its exceptionally large thermal anisotropy. While the bulk thermal conductivities along the in-plane and cross-plane directions are well-known, less understood are the microscopic properties of the thermal phonons responsible for heat conduction. In particular, recent experimental and computational works indicate that the average phonon mean free path (MFP) along the c-axis is considerably larger than that estimated by kinetic theory, but the distribution of MFPs remains unknown. Here, we report the first quantitative measurements of c-axis phonon MFP spectra in graphite at a variety of temperatures using time-domain thermoreflectance measurements of graphite flakes with variable thickness. Our results indicate that c-axis phonon MFPs have values of a few hundred nanometers at room temperature and a much narrower distribution than in isotropic crystals. At low temperatures, phonon scattering is dominated by grain boundaries separating crystalline regions of different rotational orientation. Our study provides important new insights into heat transport and phonon scattering mechanisms in graphite and other anisotropic van der Waals solids.

Sub-wavelength temperature probing in near-field laser heating by particles.

This work reports on the first time experimental investigation of temperature field inside silicon substrates under particle-induced near-field focusing at a sub-wavelength resolution. The noncontact Raman thermometry technique employing both Raman shift and full width at half maximum (FWHM) methods is employed to investigate the temperature rise in silicon beneath silica particles. Silica particles of three diameters (400, 800 and 1210 nm), each under four laser energy fluxes of 2.5 × 10(8), 3.8 ×10(8), 6.9 ×10(8) and 8.6 ×10(8) W/m(2), are used to investigate the effects of particle size and laser energy flux. The experimental results indicate that as the particle size or the laser energy flux increases, the temperature rise inside the substrate goes higher. Maximum temperature rises of 55.8 K (based on Raman FWHM method) and 29.3K (based on Raman shift method) are observed inside the silicon under particles of 1210 nm diameter with an incident laser of 8.6 × 10(8) W/m(2). The difference is largely due to the stress inside the silicon caused by the laser heating. To explore the mechanism of heating at the sub-wavelength scale, high-fidelity simulations are conducted on the enhanced electric and temperature fields. Modeling results agree with experiment qualitatively, and discussions are provided about the reasons for their discrepancy.

Noncontact sub-10 nm temperature measurement in near-field laser heating.

An extremely focused optical field down to sub-10 nm in an apertureless near-field scanning optical microscope has been used widely in surface nanostructuring and structure characterization. The involved sub-10 nm near-field heating has not been characterized quantitatively due to the extremely small heating region. In this work, we present the first noncontact thermal probing of silicon under nanotip focused laser heating at a sub-10 nm scale. A more than 200 °C temperature rise is observed under an incident laser of 1.2 × 10(7) W/m(2), while the laser polarization is well aligned with the tip axis. To explore the mechanism of heating and thermal transport at sub-10 nm scale, a simulation is conducted on the enhanced optical field by the AFM tip. The high intensity of the optical field generated in this region results in nonlinear photon absorption. The optical field intensity under low polarization angles (∼10(14) W/m(2) within 1 nm region for 15° and 30°) exceeds the threshold for avalanche breakdown in silicon. The measured high-temperature rise is a combined effect of the low thermal conductivity due to ballistic thermal transport and the nonlinear photon absorption in the enhanced optical field. Quantitative analysis reveals that under the experimental conditions the temperature rise can be about 235 and 105 °C for 15° and 30° laser polarization angles, agreeing well with the measurement result. Evaluation of the thermal resistances of the tip-substrate system concludes that little heat in the substrate can be transferred to the tip because of the very large thermal contact resistance between them.

Near-field thermal transport in a nanotip under laser irradiation.

We report on a systematic study of highly enhanced optical field and its induced thermal transport in nanotips under laser irradiation. The effects on electric field distribution caused by curvature radius, tip aspect ratio, and polarization angle of the incident laser are studied. Our Poynting vectors' study clearly shows that when a laser interacts with a metal tip, it is bent around the tip and concentrated under the apex, where extremely high field enhancement appears. This phenomenon is more like a liquid flow being forced/squeezed to go through a narrow channel. As the tip-substrate distance increases, the peak field enhancement decreases exponentially. A shift of field peak position away from the tip axis is observed. For the incident light, only its component along the tip axis direction has a contribution to the electric field enhancement under the tip apex. The optimum tip apex radius for field enhancement is about 9 nm when the half taper angle is 10°. For a tip with a fixed radius of 30 nm, field enhancement increases with the half taper angle when it is less than 25°. The thermal transport inside the nanoscale tungsten tips due to absorption of incident laser light is explored using the finite element method. A small fraction of light penetrates into the tip. As the polarization angle or apex radius increases, the peak apex temperature decreases. The peak apex temperature goes down as the half taper angle increases, even though the mean laser intensity inside the tip increases, revealing a very strong effect of the taper angle on thermal transport.

Thermophysical properties of hydrogenated vanadium-doped magnesium porous nanostructures.

Vanadium-doped magnesium nanostructures are fabricated by an oblique angle co-deposition method and hydrogenated/dehydrogenated for 21 cycles. The effective thermal conductivity and density of the MgH2 nanostructures is measured by using a photothermal system. A multilayer physical model is used to fit the experimental data. Our results show that the effective thermal conductivity of the hydrogenated V-doped Mg nanostructures is in the range of 1.16-2.40 W m(-1) K(-1) and the density falls in the range of 878-1320 kg m(-3). The measured density agrees well with the estimation from electron micrograph observation. Variation in the measurements indicates strong nonuniformity of the sample structure and thickness. Based on the measured density and effective thermal conductivity, the thermal conductivity of bulk V-doped Mg hydrides is also evaluated using Maxwell's correlation.

Effects of interleukin 18 on injury and activation of human proximal tubular epithelial cells.

BACKGROUND/AIMS: Injury and activation of tubular proximal epithelial cells (TEC) play central roles in renal tubulointerstitial fibrosis (TIF), but its mechanisms remain obscure. Interleukin 18 (IL-18) is overproduced during chronic kidney diseases (CKD), but how IL-18 affects the biological behaviour of TEC is not clear. The aim of the present study is to reveal the role of IL-18 in renal TIF. METHODS: The expressions of IL-18 and IL-18 receptor in TEC were detected by immunohistochemical staining in vivo and by reverse transcriptase polymerase chain reaction (RT-PCR) in vitro. TEC line (HK-2 cells) were incubated without or with IL-18. Cell proliferation and cell cycle were evaluated by methyl thiazolyl tetrazolium assay and flow cytometric analysis, respectively. Cell apoptosis was assessed by Hoechst 33258 staining. Expression of alpha-smooth muscle actin was evaluated by RT-PCR, immunocytochemical staining and flow cytometric analysis, respectively. Type I collagen, fibronectin, MCP-1 and RANTES in cultured supernatants were measured by enzyme-linked immunosorbent assay. RESULTS: IL-18 expression in TEC increased significantly in CKD state. IL-18 receptor was constitutively expressed in normal proximal TEC, and its expression increased strongly in CKD state. Proliferation and cell cycle of HK-2 cells were not affected by IL-18. Cell apoptosis, alpha-smooth muscle actin expression, type I collagen and fibronectin production as well as MCP-1 secretion were promoted by IL-18 in dosage- and/or time-dependent manners, but RANTES secretion was not affected. CONCLUSION: IL-18 may play a crucial role in the process of TIF by promoting TEC injury and activation, and could be a target of the therapeutic approaches against TIF.

[Transfection of dominant negative MyD88 decreases IL-8 production in bacteria-infected airway epithelial cells].

Interleukin-8 (IL-8) is an important activator and chemoattratant of neutrophils and has been implicated in airway inflammatory diseases. To explore the new gene therapeutic strategies for airway inflammation, plasmid expressing dominant negative myeloid differentiation protein (MyD88 DN) was constructed and transfected into human airway epithelial cell lines A549 and SPC-A-I. The cells were challenged with M. tuberculosis, P. aeruginosa or K. pneumoniae and the release of IL-8 was measured using ELISA. The results showed that the supernatants of M. tuberculosis and R. aeruginosa enhanced IL-8 release from the epithelial cells; and transfection of MyD88 DN diminished this effect. MyD88 DN also reduced IL-8 release from cells induced by live bacteria of P. aeruginosa or K. pneumoniae. These data suggest that MyD88 could be used as a target gene in the gene therapy of airway inflammation.