High levels of soil calcium and clay facilitate the recovery and stability of organic carbon: Insights from different land uses in the karst of China.

Soil organic carbon (SOC) is a crucial medium of the global carbon cycle and is profoundly affected by multiple factors, such as climate and management practices. However, interactions between different SOC fractions and land-use change have remained largely unexplored in karst ecosystems with widespread rock outcrops. Owing to the inherent heterogeneity and divergent response of SOC to land-use change, soil samples with close depth were collected from four typical land-use types (cropland, grassland, shrubland, and forestland) in the karst rocky desertification area of China. The aim of this study was to explore the responses of SOC dynamics to land-use types and underlying mechanism. The results showed that land-use type significantly affected SOC contents and its fractions. Compared with cropland, the other three land uses increased the total organic carbon (TOC), microbial biomass carbon (MBC), and non-labile organic carbon (NLOC) contents by 6.11-129.44%, 32.58-173.73%, and 90.98-347.00%, respectively; this demonstrated that a decrease in both labile and recalcitrant carbon resulted in SOC depletion under agricultural land use. Readily oxidized organic carbon (ROC) ranged from 42 to 69%, accounting for almost half of the TOC in the 0-40-cm soil layer. Cropland soil showed significantly higher ROC:TOC ratios than other land-use types. These results indicated that long-term vegetation restoration decreased SOC activity and improved SOC stability. Greater levels of soil exchangeable calcium (ECa) and clay contents were likely responsible for higher stabilization and then accumulation of SOC after vegetation restoration. The carbon pool index (CPI) rather than the carbon pool management index (CPMI) exhibited consistent variation trend with soil TOC contents among land-use types. Thus, further study is needed to validate the CPMI in evaluating land use effects on soil quality in karst ecosystems. Our findings suggest that land-use patterns characterized by grass or forest could be an effective approach for SOC-sequestration potential and ensure the sustainable use of soil resources in the karst area.

Physical Activity Levels and Factors Affecting Them in Hospitalized Children With Leukemia.

BACKGROUND: Physical activity promotes healthy physical and mental development in children with leukemia. However, the level of physical activity in hospitalized children with leukemia and the factors that influence it are unknown. OBJECTIVES: The aims of this study were to understand the physical activity level of hospitalized children with leukemia and to explore the factors influencing it to provide a reference for physical activity assessment and intervention in such children. METHODS: A total of 133 hospitalized children with leukemia completed a general information questionnaire, the Chinese University of Hong Kong Physical Activity Rating for Children and Youth, and the Children's Social Anxiety Scale. A cross-sectional study was used to explore the effects of different variables on the children's activity levels. RESULTS: Among the study participants, 44.4% had a low-intensity activity level, 35.3% had a moderate-intensity activity level, and 20.3% had a high-intensity activity level, with a total physical activity rating of 3 (1, 6). Chemotherapy phase (P = .007), screen time (P = .001), and social anxiety (P = .012) were identified as influential factors. CONCLUSIONS: Our results showed that children with hospitalized leukemia had lower-intensity physical activity levels, especially in the chemotherapy phase of induction remission. Furthermore, screen time and social anxiety had negative effects on the children's activity levels. IMPLICATIONS FOR PRACTICE: According to the physical activity level of the children and the influencing factors, healthcare professionals should gradually improve children's mobility and promote their physical and mental health development through guidance and encouragement, and the development of personalized activity intervention programs.

Moisture variation inferred from tree rings in north central China and its links with the remote oceans.

In this study we presented a composite standard chronology, spanning 1635-2018 to reconstruct May-July moisture variation in north central China. Our reconstruction revealed four severe dry epochs and five pronounced wet epochs. Additionally, spatial correlation analysis of our reconstruction with the actual self-calibrating Palmer drought severity index showed that our reconstruction was representative of large-scale May-July moisture changes. Both the severe dry and pronounced wet epochs showed one-to-one correspondence with other reconstructions nearby during their common periods, which demonstrated the reliability of our reconstruction backwards in time. Spectral analysis showed that significant spectral peaks were found at 2.1-3.8 years, which fell within the overall bandwidth of the El Niño-Southern Oscillations (ENSO). The spatial correlation patterns between our reconstruction and sea surface temperature (SST) in the equatorial eastern Pacific further confirmed the link between regional moisture and ENSO, with warm-phase ENSO resulting in low moisture and vice-versa. However, this link was time-dependent during the past four centuries, and was modulated by different phases of SST in the tropical Indian Ocean. Additionally, significant peaks at 24.9-46.5 years and spatial correlation patterns indicated that the Pacific Decadal Oscillation and the North Atlantic Oscillation may be the possible forcing factors of regional moisture at lower frequencies.

Valproic Acid-Like Compounds Enhance and Prolong the Radiotherapy Effect on Breast Cancer by Activating and Maintaining Anti-Tumor Immune Function.

Inadequate sustained immune activation and tumor recurrence are major limitations of radiotherapy (RT), sustained and targeted activation of the tumor microenvironment can overcome this obstacle. Here, by two models of a primary rat breast cancer and cell co-culture, we demonstrated that valproic acid (VPA) and its derivative (HPTA) are effective immune activators for RT to inhibit tumor growth by inducing myeloid-derived macrophages and polarizing them toward the M1 phenotype, thus elevate the expression of cytokines such as IL-12, IL-6, IFN-γ and TNF-α during the early stage of the combination treatment. Meanwhile, activated CD8+ T cells increased, angiogenesis of tumors is inhibited, and the vasculature becomes sparse. Furthermore, it was suggested that VPA/HPTA can enhance the effects of RT via macrophage-mediated and macrophage-CD8+ T cell-mediated anti-tumor immunity. The combination of VPA/HPTA and RT treatment slowed the growth of tumors and prolong the anti-tumor effect by continuously maintaining the activated immune response. These are promising findings for the development of new effective, low-cost concurrent cancer therapy.

Valproic acid triggers radiation-induced abscopal effect by modulating the unirradiated tumor immune microenvironment in a rat model of breast cancer.

An abscopal effect occurs when localized radiotherapy causes the regression of tumors distant from the irradiated site. However, such a clinically detectable abscopal effect from radiotherapy alone is rare. This study investigated whether valproic acid ([VPA], a histone deacetylase inhibitor [HDACi]) treatment can stimulate radiation-induced abscopal effect. We used 7,12-dimethylbenz[a]anthracene, a typical environmental carcinogen, to establish a rat model with multiple breast tumors. Only one tumor received 8 Gy fractionated doses of X-rays (2 Gy daily fractions over four days) and 200 mg/kg VPA was administered intraperitoneally. We monitored the growth of both irradiated and unirradiated tumors after treatments. The unirradiated tumor was collected for hematoxylin and eosin (HE) staining, immunohistochemistry (IHC) (CD8, Granzyme B, Cleaved Caspase-3, BrdU, Ki67, F4/80 and CD68), double immunofluorescence (F4/80 and CD86), Western blot (Cleaved Caspase-3) and qRT-PCR (CD86, CD163, IL-1ß, IL-6, IL-12, IL-23, IL-10, TGF-ß) analysis. We found ionizing radiation (IR) + VPA treatment inhibited both irradiated and unirradiated tumor growth as compared to IR alone. Such observe abscopal effect was mediated by the recruitment of activated CD8+ T cells into the unirradiated tumor sites, which released Granzyme B to cause tumor cell apoptosis. Furthermore, IR + VPA treatment led to macrophages infiltration into the unirradiated tumor sites and polarization to M1 phenotype, resulted in increased levels of pro-inflammatory cytokines such as IL-1ß and IL-12, and decreased levels of anti-inflammatory cytokines such as IL-10 and TGF-ß. Our data supports the proposition that VPA may be a potential therapeutic candidate to trigger radiation-induced abscopal effect by modulating the unirradiated tumor immune microenvironment.

Experimental Investigation on Machinability of Aluminum Alloy during Dry Micro Cutting Process Using Helical Micro End Mills with Micro Textures.

Aluminum alloy material is widely used in the electronics, weapons, aviation and aerospace industries, due to its medium strength, good corrosion resistance, good toughness and excellent oxidation properties. With the trend of product miniaturization, micro cutting has become the mainstream technique for fabricating micro parts and components, so it is very meaningful and vital to work on removing the cutting fluid from the micro cutting process and make it totally sustainable and eco-friendly. In this work, an attempt has been made to fabricate micro textures onto the rear surface of helical micro end mills with diameters of less than 1 mm. Micro textures in the form of grooves were fabricated using a noncontact low speed wire electrical discharge turning technique. Dry micro cutting experiments were carried out on an aluminum alloy material using helical micro end mills with micro textures and the dry micro cutting surface quality and tool wear have been investigated. The influence of dry micro cutting parameters on the surface roughness parameters were also investigated. Experimental results showed that the Sa and Sq can be reduced to be about 1.56 µm and 2.08 µm, respectively. Contrasting results indicate that the implantation of micro textures does not deteriorate the dry micro cutting surface but improves the machined surface consistency of an aluminum alloy workpiece. The tool wear on helical micro end mills with micro textures involved in the dry micro cutting process of Al 6061 mainly include rear frictional wear, oxidation wear and diffusion wear.

Risk of pedicle and spinous process violation during cortical bone trajectory screw placement in the lumbar spine.

BACKGROUND: Previous studies have confirmed the feasibility of the cortical bone trajectory (CBT) technique. However, there are few reports on spinous process violation and screw penetration during the screw insertion. The purpose of this study was to evaluate the incidence of spinous process violation and screw penetration through the pedicle during CBT screw insertion. METHODS: Computed tomography (CT) scans with normal lumbar structures were consecutively obtained and three-dimensional (3D) reconstructions of the lumbar spine were created. Bilateral CBT screw placement was simulated on each segment using a screw diameter of 4.5 mm, 5.0 mm, or 5.5 mm. Incidences of these complications were recorded and analyzed. RESULTS: A total of 90 patients were enrolled. Spinous process violation was observed in 68.3, 53.3, 25.5, 1.7, and 0% from L1 to L5, respectively, using 4.5 mm screws. A significant difference was found among the five segments but this was unconnected to gender or screw diameter. The incidence of screw penetration through the inner wall decreased from L1 to L4; in turn, L1 (16.7-35.5%), L2 (12.7-34.4%), L3 (2.8-23.8%) and L4 (1.1-6.7%). This trend was reversed in L5 (6.7-16.7%). Moreover, screw penetration through the outer wall was rare. The incidence of screw penetration varied with screw size as well as lumbar level, but not with gender. CONCLUSIONS: There are more difficulties of CBT screw fixation in upper lumbar spine. The low rate of screw penetration, using 4.5 mm screws, suggests the safety for CBT fixation in the lumbar spine. Larger screws (5.0 mm or 5.5 mm) are more recommended for use in the lower lumbar spine. Moreover, CBT fixation in L5 deserves greater attention because of the unique morphology of the pedicle.

Let-7 inhibits the migration and invasion of extravillous trophoblast cell via targeting MDM4.

AIMS: Extravillous trophoblast (EVT) cells migration and invasion are important causes to preeclampsia (PE). Studies have shown that let-7 was involved in inhibiting proliferation and invasion of several cancer cells, however, its effect on EVT cells migration and invasion has hardly been reported. This study aimed to explore the relation between let-7 and EVT cell migration and invasion. METHODS: MicroRNA (miRNA) and genes expression levels were measured by reverse transcription polymerase chain reaction (RT-PCR) and Western blot (WB). Cell proliferation, migration and invasion were detected by cell counting kit-8 (CCK-8) assay, wound-healing assay and transwell assay. The binding site between let-7 and murine double minute 4 (MDM4) was identified using TargetScan. The targeting relation between let-7 and MDM4 was verified using dual luciferase reporter assay. RESULTS: The results revealed that in placental tissues of PE patients, let-7, matrix metalloproteinase-2 (MMP-2) and MMP-9 were lowly expressed and tissue inhibitors of metalloproteinase-1 (TIMP-1) and TIMP-2 were highly expressed. Let-7 silencing promoted the proliferation, migration, invasion of HTR8/SVneo cells and the expression levels of MMP-2 and MMP-9, however, it inhibited TIMP-1 and TIMP-2 expression levels, while overexpression of let-7 produced the opposite results. Furthermore, MDM4 is a target gene of let-7. Rescue experiments suggested that MDM4 siRNA partially reversed the effects of let-7 silencing on cells. CONCLUSIONS: Let-7 silencing promoted proliferation, migration and invasion in EVT cells through the up-regulation of MDM4. Our study provided new insights into the molecular mechanism of PE.

East Asian summer monsoon precipitation variability since the last deglaciation.

The lack of a precisely-dated, unequivocal climate proxy from northern China, where precipitation variability is traditionally considered as an East Asian summer monsoon (EASM) indicator, impedes our understanding of the behaviour and dynamics of the EASM. Here we present a well-dated, pollen-based, ~20-yr-resolution quantitative precipitation reconstruction (derived using a transfer function) from an alpine lake in North China, which provides for the first time a direct record of EASM evolution since 14.7 ka (ka = thousands of years before present, where the "present" is defined as the year AD 1950). Our record reveals a gradually intensifying monsoon from 14.7-7.0 ka, a maximum monsoon (30% higher precipitation than present) from ~7.8-5.3 ka, and a rapid decline since ~3.3 ka. These insolation-driven EASM trends were punctuated by two millennial-scale weakening events which occurred synchronously to the cold Younger Dryas and at ~9.5-8.5 ka, and by two centennial-scale intervals of enhanced (weakened) monsoon during the Medieval Warm Period (Little Ice Age). Our precipitation reconstruction, consistent with temperature changes but quite different from the prevailing view of EASM evolution, points to strong internal feedback processes driving the EASM, and may aid our understanding of future monsoon behaviour under ongoing anthropogenic climate change.

A test of climate, sun, and culture relationships from an 1810-year Chinese cave record.

A record from Wanxiang Cave, China, characterizes Asian Monsoon (AM) history over the past 1810 years. The summer monsoon correlates with solar variability, Northern Hemisphere and Chinese temperature, Alpine glacial retreat, and Chinese cultural changes. It was generally strong during Europe's Medieval Warm Period and weak during Europe's Little Ice Age, as well as during the final decades of the Tang, Yuan, and Ming Dynasties, all times that were characterized by popular unrest. It was strong during the first several decades of the Northern Song Dynasty, a period of increased rice cultivation and dramatic population increase. The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.