Size, distribution, and vulnerability of the global soil inorganic carbon.

Global estimates of the size, distribution, and vulnerability of soil inorganic carbon (SIC) remain largely unquantified. By compiling 223,593 field-based measurements and developing machine-learning models, we report that global soils store 2305 ± 636 (±1 SD) billion tonnes of carbon as SIC over the top 2-meter depth. Under future scenarios, soil acidification associated with nitrogen additions to terrestrial ecosystems will reduce global SIC (0.3 meters) up to 23 billion tonnes of carbon over the next 30 years, with India and China being the most affected. Our synthesis of present-day land-water carbon inventories and inland-water carbonate chemistry reveals that at least 1.13 ± 0.33 billion tonnes of inorganic carbon is lost to inland-waters through soils annually, resulting in large but overlooked impacts on atmospheric and hydrospheric carbon dynamics.

Pervasive soil phosphorus losses in terrestrial ecosystems in China.

Future phosphorus (P) shortages could seriously affect terrestrial productivity and food security. We investigated the changes in topsoil available P (AP) and total P (TP) in China's forests, grasslands, paddy fields, and upland croplands during the 1980s-2010s based on substantial repeated soil P measurements (63,220 samples in the 1980s, 2000s, and 2010s) and machine learning techniques. Between the 1980s and 2010s, total soil AP stock increased with a small but significant rate of 0.13 kg P ha-1 year-1 , but total soil TP stock declined substantially (4.5 kg P ha-1 year-1 ) in the four ecosystems. We quantified the P budgets of soil-plant systems by harmonizing P fluxes from various sources for this period. Matching trends of soil contents over the decades with P budgets and fluxes, we found that the P-surplus in cultivated soils (especially in upland croplands) might be overestimated due to the great soil TP pool compared to fertilization and the substantial soil P losses through plant uptake and water erosion that offset the P additions. Our findings of P-deficit in China raise the alarm on the sustainability of future biomass production (especially in forests), highlight the urgency of P recycling in croplands, and emphasize the critical role of country-level basic data in guiding sound policies to tackle the global P crises.

[Horizontal Variation Characteristics of Alpine Grassland Soil Function and Vertical Changes Along Soil Genetic Horizons in the Three-River Headwaters Region].

The Three-River Headwaters region is a hotspot for studying the response of soil function to climate change. To study the horizontal variation characteristics of alpine grassland soil function and vertical changes along soil genetic horizons, soil functional indicators (including respiration, nitrogen conversion rate, and enzymatic activity) of different genetic horizons in alpine grassland soil profiles and their correlations with environmental factors were analyzed. The results showed that there were no significant differences in soil functional characteristics between alpine meadows and steppes, and topsoil had higher respiration rates, nitrogen conversion rates, and enzymatic activities than those of subsoil. Total nitrogen was a key driver of soil functional characteristics in different genetic horizons, explaining 18.3%, 21.4%, and 27.5% of the horizontal variation in functional characteristics, respectively. Climate and vegetation factors mainly affected soil function indirectly by changing soil physicochemical properties in topsoil, but atmospheric nitrogen deposition still affected soil function in subsoil. These results indicate the significant nitrogen limitation of alpine grassland soil in the Three-River Headwaters region, and the findings provide a new insight into the maintenance of soil functional diversity and the response to climate change in the context of global climate change.

Deep accumulation of soluble organic nitrogen after land-use conversion from woodlands to orchards in a subtropical hilly region.

Accumulation of soluble organic nitrogen (SON) in soil poses a significant threat to groundwater quality and plays an important role in regulating the global nitrogen cycle; however, most related studies have focused only on the upper 100-cm soil layers. Surface land-use management and soil properties may affect the vertical distribution of SON; however, their influence is poorly understood in deep soil layers. Therefore, this study assessed the response of SON concentration, pattern, and storage in deep regoliths to land-use conversion from woodlands to orchards in a subtropical hilly region. Our results showed that the SON stocks of the entire soil profile (up to 19.5 m) ranged from 254.5 kg N ha-1 to 664.1 kg N ha-1. Land-use conversion not only reshaped the distribution pattern of SON, but also resulted in substantial accumulation of SON at the 0-200 cm soil profile in the orchards compared to that in the woodlands (124.1 vs 190.5 kg N ha-1). Land-use conversion also altered the SON/total dissolved nitrogen ratio throughout the regolith profile, resulting in a relatively low (<50 %) ratio in orchard soils below 200 cm. Overall, 76.8 % of SON (338.4 ± 162.0 kg N ha-1) was stored in the layers from 100 cm below the surface to the bedrock. Regolith depth (r = -0.52 and p < 0.05) was found to be significantly correlated with SON concentration, explaining 17.8 % of the variation in SON, followed by total nitrogen (14.4 %), total organic carbon/total nitrogen ratio (10.1 %), and bulk density (9.3 %). This study provides insights into the estimation of terrestrial nitrogen and guidance for mitigation of groundwater contamination risk due to deep accumulation of SON.

Effect of Decompressive Craniectomy with Stepwise Decompression of the Intracranial Compartment on Postoperative Neurologic Function, Hemodynamics, and Glasgow Outcome Scale Score of Patients with Severe Traumatic Brain Injury.

BACKGROUND: We assess the effects of standard decompressive craniectomy with stepwise decompression of the intracranial compartment on the postoperative neurologic function, hemodynamics, and Glasgow Outcome Scale (GOS) score of patients with severe traumatic brain injury (sTBI). METHODS: One hundred sTBI patients admitted from July 2017 to February 2019 were enrolled and randomly divided into step and standard groups (n = 50) using a random number table. The standard group received traditional standard decompression during surgery, while the step group underwent multistep decompression during surgery. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were measured immediately after surgery (T0), 3 hours after surgery (T1), 6 hours after surgery (T2), and 12 hours after surgery (T3). The postoperative Glasgow Coma Scale (GCS) score, neurologic function deficit score, and GOS score were evaluated. RESULTS: After treatment, the excellent/good rate of neurologic function improvement and GCS and GOS scores of the step group significantly exceeded those of the standard group (p < 0.05). Compared with the standard group, the HR, SBP, DBP, and MAP decreased significantly in the step group at T1, T2, and T3 (p < 0.05). CONCLUSION: Standard decompressive craniectomy under multistep decompression can markedly improve the neurologic function, hemodynamics, and prognosis of patients.

Mapping high resolution National Soil Information Grids of China.

Soil spatial information has traditionally been presented as polygon maps at coarse scales. Solving global and local issues, including food security, water regulation, land degradation, and climate change requires higher quality, more consistent and detailed soil information. Accurate prediction of soil variation over large and complex areas with limited samples remains a challenge, which is especially significant for China due to its vast land area which contains the most diverse soil landscapes in the world. Here, we integrated predictive soil mapping paradigm with adaptive depth function fitting, state-of-the-art ensemble machine learning and high-resolution soil-forming environment characterization in a high-performance parallel computing environment to generate 90-m resolution national gridded maps of nine soil properties (pH, organic carbon, nitrogen, phosphorus, potassium, cation exchange capacity, bulk density, coarse fragments, and thickness) at multiple depths across China. This was based on approximately 5000 representative soil profiles collected in a recent national soil survey and a suite of detailed covariates to characterize soil-forming environments. The predictive accuracy ranged from very good to moderate (Model Efficiency Coefficients from 0.71 to 0.36) at 0-5 cm. The predictive accuracy for most soil properties declined with depth. Compared with previous soil maps, we achieved significantly more detailed and accurate predictions which could well represent soil variations across the territory and are a significant contribution to the GlobalSoilMap.net project. The relative importance of soil-forming factors in the predictions varied by specific soil property and depth, suggesting the complexity and non-stationarity of comprehensive multi-factor interactions in the process of soil development.

Environmental selection dominates over dispersal limitation in shaping bacterial biogeographical patterns across different soil horizons of the Qinghai-Tibet Plateau.

Soil microbial biogeographical patterns have been widely explored from horizontal to vertical scales. However, studies of microbial vertical distributions were still limited (e.g., how soil genetic horizons influence microbial distributions). To shed light on this question, we investigated soil bacterial communities across three soil horizons (topsoil: horizon A; midsoil: horizon B; subsoil: horizon C) of 60 soil profiles along a 3500 km transect in the Qinghai-Tibet Plateau. We found that bacterial diversity was highest in the topsoil and lowest in the subsoil, and community composition significantly differed across soil horizons. The network complexity decreased from topsoil to subsoil. There were significant geographical/environmental distance-decay relationships (DDR) in three soil horizons, with a lower slope from topsoil to subsoil due to the decreased environmental heterogeneity. Variation partitioning analysis (VPA) showed that bacterial community variations were explained more by environmental than spatial factors. Although environmental selection processes played a dominant role, null model analysis revealed that deterministic processes (mainly variable selection) decreased with deeper soil horizons, while stochastic processes (mainly dispersal limitation) increased from topsoil to subsoil. These results suggested that microbial biogeographical patterns and community assembly processes were soil horizon dependent. Our study provides new insights into the microbial vertical distributions in large-scale alpine regions and highlights the vital role of soil genetic horizons in affecting microbial community assembly, which has implications for understanding the pedogenetic process and microbial responses to extreme environment under climate change.

Distribution Characteristics of Soil Viruses Under Different Precipitation Gradients on the Qinghai-Tibet Plateau.

Viruses are extremely abundant in the soil environment and have potential roles in impacting on microbial population, evolution, and nutrient biogeochemical cycles. However, how environment and climate changes affect soil viruses is still poorly understood. Here, a metagenomic approach was used to investigate the distribution, diversity, and potential biogeochemical impacts of DNA viruses in 12 grassland soils under three precipitation gradients on the Qinghai-Tibet Plateau, which is one of the most sensitive areas to climate change. A total of 557 viral operational taxonomic units were obtained, spanning 152 viral families from the 30 metagenomes. Both virus-like particles (VLPs) and microbial abundance increased with average annual precipitation. A significant positive correlation of VLP counts was observed with soil water content, total carbon, total nitrogen, soil organic matter, and total phosphorus. Among these biological and abiotic factors, SWC mainly contributed to the variability in VLP abundance. The order Caudovirales (70.1% of the identified viral order) was the predominant viral type in soils from the Qinghai-Tibet Plateau, with the Siphoviridae family being the most abundant. Remarkably, abundant auxiliary carbohydrate-active enzyme (CAZyme) genes represented by glycoside hydrolases were identified, indicating that soil viruses may play a potential role in the carbon cycle on the Qinghai-Tibet Plateau. There were more diverse hosts and abundant CAZyme genes in soil with moderate precipitation. Our study provides a strong evidence that changes in precipitation impact not only viral abundance and virus-host interactions in soil but also the viral functional potential, especially carbon cycling.

Significant loss of soil inorganic carbon at the continental scale.

Widespread soil acidification due to atmospheric acid deposition and agricultural fertilization may greatly accelerate soil carbonate dissolution and CO2 release. However, to date, few studies have addressed these processes. Here, we use meta-analysis and nationwide-survey datasets to investigate changes in soil inorganic carbon (SIC) stocks in China. We observe an overall decrease in SIC stocks in topsoil (0-30 cm) (11.33 g C m-2 yr-1) from the 1980s to the 2010s. Total SIC stocks have decreased by ∼8.99 ± 2.24% (1.37 ± 0.37 Pg C). The average SIC losses across China (0.046 Pg C yr-1) and in cropland (0.016 Pg C yr-1) account for ∼17.6%-24.0% of the terrestrial C sink and 57.1% of the soil organic carbon sink in cropland, respectively. Nitrogen deposition and climate change have profound influences on SIC cycling. We estimate that ∼19.12%-19.47% of SIC stocks will be further lost by 2100. The consumption of SIC may offset a large portion of global efforts aimed at ecosystem carbon sequestration, which emphasizes the importance of achieving a better understanding of the indirect coupling mechanisms of nitrogen and carbon cycling and of effective countermeasures to minimize SIC loss.

Elevated Serum Complement C1q Levels After Traumatic Brain Injury and Its Association with Poor Prognosis.

OBJECTIVE: Complement C1q is implicated in neuroinflammation. We intended to discern the relationship between serum C1q levels and severity in addition to prognosis following traumatic brain injury (TBI). METHODS: In this prospective, observational study, serum C1q levels were quantified in 188 TBI patients and 188 healthy controls. Glasgow coma scale (GCS) and Rotterdam computed tomography (CT) classification were used as clinical and radiological indicators of severity. Patients with extended Glasgow outcome scale (GOSE) score of 1-4 at 6 months after trauma were considered to have a poor outcome. Multiple logistic regression model was built to ascertain the independent association of serum C1q levels with 6-month poor outcome. Receiver operating characteristic (ROC) curve was configured for analysis of prognostic capability with respect to serum C1q levels. RESULTS: TBI patients exhibited substantially higher serum C1q levels than controls (median, 223.9 mg/l versus 75.4 mg/l). Serum C1q levels of patients were tightly correlated with GCS score (r = -0.671), Rotterdam CT classification (r = 0.604) and GOSE score (r = -0.581). An area under the ROC curve was yielded of 0.793 (95% confidence interval = 0.728-0.849), and serum C1q levels above 345.5 mg/l discriminated the risk of 6-month poor outcome with 59.6% sensitivity and 92.6% specificity. Serum C1q levels above 345.5 mg/l retained as an independent predictor for 6-month poor outcome with odds ratio of 4.922 (95% confidence interval = 1.552-15.606; P = 0.017). CONCLUSION: Elevated serum C1q levels are closely correlated with traumatic severity and independently predicted the risk of long-term poor prognosis after TBI.

Hydrogen-rich saline alleviates early brain injury through regulating of ER stress and autophagy after experimental subarachnoid hemorrhage.

PURPOSE: Subarachnoid hemorrhage (SAH) is a common complication of cerebral vascular disease. Hydrogen has been reported to alleviate early brain injury (EBI) through oxidative stress injury, reactive oxygen species (ROS), and autophagy. Autophagy is a programmed cell death mechanism that plays a vital role in neuronal cell death after SAH. However, the precise role of autophagy in hydrogen-mediated neuroprotection following SAH has not been confirmed. METHODS: In the present study, the objective was to investigate the neuroprotective effects and potential molecular mechanisms of hydrogen-rich saline in SAH-induced EBI by regulating neural autophagy in the C57BL/6 mice model. Mortality, neurological score, brain water content, ROS, malondialdehyde (MDA), and neuronal death were evaluated. RESULTS: The results show that hydrogen-rich saline treatment markedly increased the survival rate and neurological score, increased neuron survival, downregulated the autophagy protein expression of Beclin-1 and LC3, and endoplasmic reticulum (ER) stress. That indicates that hydrogen-rich saline-mediated inhibition of autophagy and ER stress ameliorate neuronal death after SAH. The neuroprotective capacity of hydrogen-rich saline is partly dependent on the ROS/Nrf2/heme oxygenase-1 (HO-1) signaling pathway. CONCLUSIONS: The results of this study demonstrate that hydrogen-rich saline improves neurological outcomes in mice and reduces neuronal death by protecting against neural autophagy and ER stress.

Hydrogen-rich saline alleviates early brain injury through regulating of ER stress and autophagy after experimental subarachnoid hemorrhage

ABSTRACT Purpose: Subarachnoid hemorrhage (SAH) is a common complication of cerebral vascular disease. Hydrogen has been reported to alleviate early brain injury (EBI) through oxidative stress injury, reactive oxygen species (ROS), and autophagy. Autophagy is a programmed cell death mechanism that plays a vital role in neuronal cell death after SAH. However, the precise role of autophagy in hydrogen-mediated neuroprotection following SAH has not been confirmed. Methods: In the present study, the objective was to investigate the neuroprotective effects and potential molecular mechanisms of hydrogen-rich saline in SAH-induced EBI by regulating neural autophagy in the C57BL/6 mice model. Mortality, neurological score, brain water content, ROS, malondialdehyde (MDA), and neuronal death were evaluated. Results: The results show that hydrogen-rich saline treatment markedly increased the survival rate and neurological score, increased neuron survival, downregulated the autophagy protein expression of Beclin-1 and LC3, and endoplasmic reticulum (ER) stress. That indicates that hydrogen-rich saline-mediated inhibition of autophagy and ER stress ameliorate neuronal death after SAH. The neuroprotective capacity of hydrogen-rich saline is partly dependent on the ROS/Nrf2/heme oxygenase-1 (HO-1) signaling pathway. Conclusions: The results of this study demonstrate that hydrogen-rich saline improves neurological outcomes in mice and reduces neuronal death by protecting against neural autophagy and ER stress.

Deep Nitrate Accumulation in a Highly Weathered Subtropical Critical Zone Depends on the Regolith Structure and Planting Year.

Nitrate accumulated deep (>100 cm) in the regolith (soil and saprolite) threatens groundwater quality, but most studies focus only on nitrate nearer the surface (<100 cm). Surface soil management versus regolith interactions affect deep nitrate leaching, but their combined impact remains unclear. This study measured how deep nitrate accumulation was affected by crop practices including orchard/cropland planting years, regolith structure, and soil properties in highly weathered subtropical red soils. Deep nitrate storage varied from 43.6 to 1116.3 kg ha-1. Regolith thickness was positively correlated with nitrate storage (R2 = 0.43, p < 0.05). Reticulated red clay (110-838 cm) had 81% of the accumulated nitrate and overlapped with 79% of the nitrate accumulation layer. All of the nitrate accumulation parameters (except for peak depth (PD)) generally increased with the planting years. The difference in peak nitrate concentration (9.0-20.0 mg kg-1) with planting year gradient (3-58 years) varied by 2.2 times, and the difference in nitrate storage (43.6-425.7 kg ha-1) varied by 9.8 times. Texture and pH explain 41.6% of the variation in nitrate concentration. As soil management practices interact with deeper regolith to control the spatial pattern of nitrate accumulation, vulnerable regions could be identified to avoid high accumulation.

Global Trends of Researches on Sacral Fracture Surgery: A Bibliometric Study Based on VOSviewer.

STUDY DESIGN: Bibliometric analysis. OBJECTIVE: This study aims to identify and summarize the articles related to sacral fracture surgery, to compare the papers from different countries and journals, to show the trends of researches on sacral fracture surgery. SUMMARY OF BACKGROUND DATA: In recent years, studies on sacral fracture are growing rapidly, but there were no bibliometric studies regarding sacral fracture surgery. METHODS: Excel 2016 and VOSviewer were used to identify and summarize the articles from Web of Science between 1900 and 2018. Publication number, publication year, publication country, publication organization, publication source, author, sum of times cited, H-index, and journal's impact factors were recorded and analyzed. Bibliometric maps of co-citations and maps of co-occurrence of keywords are drawn. RESULTS: A total of 611 publications were extracted. United States published most articles (227, 37.2%), both total citations (3536) and H-index (32) of United States ranked first of all the countries. The most productive organization on sacral fracture surgery is Johns Hopkins University (14). Spine (43) published the most articles on sacral fracture surgery. The latest keyword "patterns" appeared in 2017 in 5 articles. Other relatively new keywords include "proximal junctional kyphosis," "spondylopelvic dissociation," "fragility fracture," "lumbopelvic fixation" that appeared in 2017 in eight, six, six, and 25 articles, respectively. CONCLUSION: This bibliometric study showed that there is a growing trend both in published articles related to sacral fracture surgery and relative research interest in the last 30 years. United States dominates the research regarding sacral fracture surgery. Johns Hopkins University, Johannes Gutenberg University of Mainz, and Harborview Medical Center are the best institutions related to sacral fracture surgery research. Spine, J Orthop Trauma, and Injury are the top three productive journals on sacral fracture surgery. Sacral fracture patterns, proximal junctional kyphosis, spondylopelvic dissociation, fragility fracture, and lumbopelvic fixation may be the new research hotspot in this field. LEVEL OF EVIDENCE: 5.

Intra-horizon differentiation of the bacterial community and its co-occurrence network in a typical Plinthic horizon.

Subsurface soil bacterial community composition and the controlling factors remain largely unknown, especially the micro-zone differentiation of community composition within a horizon. We studied a plinthic horizon to determine how different micro-zones in a horizon affect the bacterial community. The plinthic horizon is a net-like horizon characterized by the segregation of iron forms as shown by contrasting red matrix and white veins, which share common macro-environmental conditions such as climate and land use but differ only in physical and chemical compositions. The studied horizon is typical of the red soils of southeastern China and is an important layer in the red soil Critical Zone. The plinthite is considered to have been formed in the Quaternary and thus is a record of the paleo-environment. We evaluated the difference in the bacterial community composition between the red matrix and white veins and explored the possible assembly mechanisms of their co-occurrence patterns. Compared to the eutrophic environments of a red matrix, higher relative abundances of Acidobacteria and Nitrospirae were observed in the white veins. Similarly, more niches led to a higher density of bacterial co-occurrence patterns in the red matrix. The differences in the bacterial community composition and association networks are due to environmental selection, including the legacy of the paleoclimate that is represented by major element contents and contemporary hydrological properties that are mainly controlled by the soil texture. Our study shows that micro-zones even within a same plinthic horizon can provide different habitats and thus select for specific bacterial communities. Furthermore, this study could improve our understanding of the differentiation of bacterial communities among microenvironments caused by both historical and contemporary processes and help to predict how these communities may respond to future environmental changes.

Atomic force microscopy measurements of bacterial adhesion and biofilm formation onto clay-sized particles.

Bacterial adhesion onto mineral surfaces and subsequent biofilm formation play key roles in aggregate stability, mineral weathering, and the fate of contaminants in soils. However, the mechanisms of bacteria-mineral interactions are not fully understood. Atomic force microscopy (AFM) was used to determine the adhesion forces between bacteria and goethite in water and to gain insight into the nanoscale surface morphology of the bacteria-mineral aggregates and biofilms formed on clay-sized minerals. This study yields direct evidence of a range of different association mechanisms between bacteria and minerals. All strains studied adhered predominantly to the edge surfaces of kaolinite rather than to the basal surfaces. Bacteria rarely formed aggregates with montmorillonite, but were more tightly adsorbed onto goethite surfaces. This study reports the first measured interaction force between bacteria and a clay surface, and the approach curves exhibited jump-in events with attractive forces of 97 ± 34 pN between E. coli and goethite. Bond strengthening between them occurred within 4 s to the maximum adhesion forces and energies of -3.0 ± 0.4 nN and -330 ± 43 aJ (10(-18) J), respectively. Under the conditions studied, bacteria tended to form more extensive biofilms on minerals under low rather than high nutrient conditions.

Enhanced photodegradation of pentachlorophenol by single and mixed cationic and nonionic surfactants.

The photocatalytic degradation of pentachlorophenol (PCP) using a TiO(2) catalyst in a surfactant-containing system was investigated. PCP abatement by photocatalysis was significantly enhanced by the addition of cationic and nonionic surfactants, both single and mixed, at appropriate concentrations. The enhanced photodegradation can be mainly attributed to the formation of admicelles on the TiO(2) surface. This phenomenon can lead to the incorporation of more PCP, thereby providing TiO(2) with remarkably higher capture rates for target pollutants. Hence, PCP was rendered easily available to photo-yielded oxidative radicals on the catalyst surface. Notably, mixed cationic-nonionic surfactants yielded much higher photodegradation efficiencies than the corresponding single surfactants, indicating the existence of a synergistic effect in the complex system. The adsorption behavior of PCP on TiO(2) in the surfactant solutions was investigated to elucidate this synergism. Fourier-transform infrared (FTIR) spectroscopy was adopted to gain insight into the structural changes induced by the surfactants and a better understanding of the surfactant-assisted photocatalytic degradation mechanism was obtained.

Emodin potentiates the antitumor effects of gemcitabine in PANC-1 pancreatic cancer xenograft model in vivo via inhibition of inhibitors of apoptosis.

Pancreatic cancer is a highly aggressive malignant disease. Gemcitabine is currently the standard first-line chemotherapeutic agent for pancreatic cancer. As members of apoptosis inhibitors, Survivin and XIAP play an important role in chemotherapy resistance in pancreatic cancer. Emodin has therapeutic potential against cancers. This study was designed to investigate whether combination therapy with gemcitabine and emodin enhanced antitumor efficacy in pancreatic cancer. The application of the combination therapy triggered significantly higher frequency of pancreatic cancer cell apoptosis. Our research demonstrated that the combination of emodin and gemcitabine resulted in significantly reduced tumor volumes compared to gemcitabine or emodin treatment alone. Immunohistochemistry and western immunoblot analyses showed that Survivin and XIAP expression were downregulated in emodin and the combination groups compared to the other two groups. Reverse transcriptase polymerase chain reaction analyses showed that Survivin and XIAP mRNA expression in emodin and the combination groups were downregulated significantly compared to the other two groups. Furthermore, the expression of the nuclear transcription factor κB (NF-κB) protein and NF-κB mRNA were downregulated in the emodin and the combination groups. DNA-binding activity of NF-κB was inhibited in emodin and combination groups compared to the other groups. This study suggests that emodin potentiates the antitumor effects of gemcitabine in PANC-1 cell xenografts via promotion of apoptosis and IAP suppression.

Optimization of supercritical phase and combined supercritical/subcritical conversion of lignocellulose for hexose production by using a flow reaction system.

A flow reaction system was utilized to investigate lignocellulose conversion using combined supercritical/subcritical conditions for hexose production. Initially, investigation of cellulose hydrolysis in supercritical water and optimization of reaction parameters were done. Oligosaccharide yields reached over 30% at cellulose concentrations of 3-5 gL(-1) and reaction times of 6-10s at 375 °C, and 2.5-4 gL(-1) and 8-10s at 380 °C. Temperatures above 380 °C were not appropriate for the supercritical phase in the combined process. Subsequently, conversion of lignocellulosic materials under combined supercritical/subcritical conditions was studied. Around 30% hexose was produced from corn stalks under the optimal parameters for supercritical (380 °C, 23-24 MPa, 9-10s) and subcritical (240 °C, 8-9 MPa, 45-50s) phases. Flow systems utilizing the combined supercritical/subcritical technology present a promising method for lignocellulosic conversion. The results of this study provide an important guide for the operational optimization and practical application of the proposed system.

Evolution of unsaturated hydraulic properties of municipal solid waste with landfill depth and age.

Successful modeling of liquid and air flow and hence designing of liquid and air addition systems in the landfills are constrained by the lack of key parameters of unsaturated hydraulic properties of municipal solid waste (MSW), which are strongly dependent on the depth of burial and the degree of decomposition. In this study, water retention curves (WRC) of MSW are measured using pressure plate method on samples repacked according to the in situ unit weight measured during borehole sampling, representing the MSW in shallow, middle, and deep layers. The measured WRC of MSW is well-reproduced by the van Genuchten-Mualem model, and is used to predict the unsaturated hydraulic properties of MSW, including water retention characteristics and unsaturated hydraulic conductivity. The estimated model parameters are consistent with other studies, suggesting that the pressure plate method yields reproducible results. As the landfill depth and age increase, the overburden pressure, the highly decomposed organic matter and finer pore space increase, hence the capillary pressure increases, causing increases in air-entry values, field capacity and residual water content, and decreases in steepness of WRC and saturated water content. The unsaturated hydraulic properties of MSW undergo changes with landfill depth and age, showing more silt loam-like properties as the landfill age increases.