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We demonstrate that a convex combination of the Nagumo and Perron growth conditions guarantees the existence of a unique solution to an ordinary differential equation, which can be obtained as the uniform limit of a sequence of successive approximations. Furthermore, we give a sufficient condition for the pathwise uniqueness of solutions to stochastic differential equations driven by Brownian motions. [ABSTRACT FROM AUTHOR]

In this paper, a non‐standard finite difference scheme is developed to solve the space fractional advection–diffusion equation. By using Fourier–Von Neumann method, we prove that non‐standard finite difference scheme is unconditionally stable. We further discuss the convergence of numerical method and give the order of convergence. The numerical examples show that the non‐standard finite difference method can effectively reduce the maximum error and improve the accuracy of numerical solution in contrast to classical numerical methods. Moreover, we find that our numerical scheme is very flexible, when we optimize the denominator function of time and space simultaneously, the performance is the best. These studies show that the non‐standard finite difference scheme is feasible and efficient for solving fractional partial differential equations. [ABSTRACT FROM AUTHOR]

N-ethylcarbazole (NEC) is one of the most promising liquid organic hydrogen carriers (LOHCs) due to its low dehydrogenation enthalpy. The development of an efficient catalyst for the dehydrogenation of dodecahydro-N-ethylcarbazole (H 12 -NEC) is the key to the large-scale application of LOHCs. In this paper, Ni/MCM-41 was prepared by chemical reduction method using MCM-41 as the carrier, and then MCM-41 loaded Ni n @Pd 1 core-shell nanocatalysts (Ni n @Pd 1 /M41) were prepared by ultrasound-assisted galvanic replacement method using Ni as the templating agent and reducing agent. It was shown that there was electron transfer between Ni and Pd, and SMSI effect of Ni n @Pd 1 with MCM-41 by the characterization results of Ni n @Pd 1 /M41, which promoted the catalytic performance. H 12 -NEC dehydrogenation efficiency over Ni 6 @Pd 1 /M41 reached 100% at 180 °C for 4 h and at 170 °C for 6 h, and 97.58% for 6 h at 160 ℃, and TOF was 5080.6 h−1, which was better than that reported in the literature. The excellent catalytic dehydrogenation performance of Ni 6 @Pd 1 /M41 can mainly be attributed to the synergistic effect of coordination and strain effects between the bimetals. [Display omitted] • Ni n @Pd 1 /M41 core-shell catalysts for H 12 -NEC dehydrogenation were prepared by ultrasound-assisted galvanic replacement. • Coordination and strain effect between Ni and Pd, SMSI effect of Ni n @Pd 1 with MCM-41 improved the catalytic performance. • H 12 -NEC dehydrogenation efficiency over Ni 6 @Pd 1 /M41 reached 100% at 180 ℃ for 4 h and at 170 ℃ for 6 h. • TOF of H 12 -NEC dehydrogenation over Ni 6 @Pd 1 /M41 was 5080.6 h−1. [ABSTRACT FROM AUTHOR]

The prediction of carbon price is exceedingly essential for the regulators, investors, and participants of the carbon trading market. It is the basis for formulating market policies and improving risk management capabilities. China's carbon price series are nonlinear and nonstationary, so it is difficult to predict accurately with traditional models. This paper proposes a multiscale ensemble prediction model based on ensemble empirical mode decomposition (EEMD‐ADD) to improve the prediction accuracy of carbon price. Firstly, EEMD is used to decompose the carbon price sequence into several intrinsic mode functions (IMFs), and these IMFs are divided into high‐frequency component, low‐frequency component and the trend component. Then, LSSVM, PSO‐LSSVM, and BA‐LSSVM are used to predict the three components respectively after comparative analysis. Finally, the results are combined to obtain the final prediction value. In the empirical analysis of the Hubei Emissions Exchange, the proposed model outperforms other comparative models. The RMSE, MAE, and MAPE values of the EEMD‐ADD model are 0.6180, 0.4726, and 1.6342, and the DS, CP, and CD values are 94.36, 92.16, and 96.48. In addition, the model performed best in other time periods. The results suggest that the proposed model is effective and could predict carbon prices more accurately. [ABSTRACT FROM AUTHOR]

Interactive display is an important part of electronic devices. It is widely used in smartphones, laptops, and industrial equipment. To achieve 3-dimensional detection, the piezoelectric touch panel gains great popularity for its advantages of high sensitivity, low cost, and simple structure. In order to help readers understand the basic principles and the current technical status, this article introduces the work principles of the piezoelectric touch panel, widely-used piezoelectric materials and their characteristics, as well as the applications of the piezoelectric touch panel. The challenges and future trends are also discussed. [ABSTRACT FROM AUTHOR]

Owing to the limited natural distributions and special medicine-industrial values of Viola philippica , it's urgently needed to explore its population-level differences for promoting the resource utilization efficiencies of this plant. The hypothesis of this study was that different populations of V. philippica plants would have broad-scale differences and interactions of leaf-accumulated metabolites and leaf-colonized bacteria. Hence, two populations (vi-p and vi-j) of this plant were typically collected in China for analyzing multiomics. At first, vi-p and vi-j leaf metabolomes (LMs) were presented with 1,003 metabolites; in contrast of vi-p-LMs, 445 differently accumulated metabolites (DAMs) were identified in vi-j-LMs, with the only up-regulated lipids, vitamin and ketone compounds, the only down-regulated aldehyde compounds, the most up-regulated flavonoids, and the most down-regulated phenylpropanoid compounds. In comparative of vi-p leaf transcriptomes (LTs), 4,645 differently expressed genes (DEGs) were identified in vi-j-LTs, which were typically involved in a series of extracellular defenses and secondary metabolic pathways; the DEGs were frequently co-enriched with DAMs in three biosynthesis pathways of phenylpropanoid, flavonoid, and α-linolenic acid. Furthermore, these DAMs were also found to have the significant correlations with some different types or/and abundances of leaf-assembled bacteria (DTAB) between vi-p and vi-j leaf-assembled bacterial communities (LABCs). Taken together, this study reveals the broad-scale patterns of regulating vi-p and vi-j leaf DAMs with DEGs and DTAB, suggesting that it's essential of keeping plant-population and -habitat diversities for harvesting population-level DAMs in V. philippica. • The plant-level functional metabolites were integrally uncovered in V. philippica. • Two plant populations were identified with differently accumulated metabolites (DAMs). • The typical DAMs were co-enriched with differently expressed genes (DEGs). • These DAMs were also correlated with different types or/and abundances bacteria (DTAB). [ABSTRACT FROM AUTHOR]

• A bactericidal shape memory polyurethanes (SMPU) composite film was prepared. • Biofilm can be detached from the surface of the film upon a thermal stimulation. • The SMPU composite film shows low cell cytotoxicity, without leaching of bactericidal species. Biofilms that are responsible for a variety of chronic infections and antibiotic resistance have drawn much attention worldwide. A new strategy for mechanically disrupting and removing biofilms by thermal-triggered shape memory polyurethanes (SMPU) film composited with zinc oxide nanoparticles (ZnO NPs) is reported here. Upon thermal triggered shape recovery, most of the adhered biofilm can be detached from the surface of the SMPU, while the incorporated ZnO NPs could efficiently eliminate the adhered initially and residual bacteria after detaching activity, without leaching of bactericidal species. Furthermore, the composite films exhibited low cytotoxicity to mammalian cells as revealed by cell viability tests. We envision that this antibacterial strategy may find unique applications in biomedical devices, especially for those biofilm-associated infections. [ABSTRACT FROM AUTHOR]

• A new nanoprobe (DTAAT) has been designed based on DNA tetrahedral supported hybridization chain reaction (HCR) for in situ analysis of bacteria. • DTAAT can recognize bacteria by dual binding of antibody and aptamer, which improves specificity and sensitivity for in situ analysis of bacteria. • DTAAT as a nanoprobe can be used for in situ imaging and quantitative analysis of bacteria. A new nanoprobe (DTAAT) has been well designed based on DNA tetrahedron supported hybridization chain reaction (HCR) and further applied for in situ analysis of bacteria. Antibody-aptamer conjugate (AA) has been coupled with DNA tetrahedron (DT) followed by the linkage of trigger strand (A). Bacteria can be preciously recognized by dual binding of both antibody and aptamer in DTAAT, to release trigger strand which is complementary with aptamer. By virtue of proximity effect, the released trigger strand can further efficiently induce the simultaneous occurrence of arrays of HCR at three vertices of DT, with rapid reaction rate of 359.29 min−1 in comparison with that of 212.60 min−1 for free HCR. DTAAT can be served for in situ imaging of bacteria by confocal laser scanning microscopy and single-cell characterization by flow cytometry. Moreover, using DTAAT as probe, the quantitative analysis of bacteria can be realized with high specificity and anti-interference capability. In a word, the developed DTAAT nanoprobe has a great potential for accurate and sensitive in situ analysis of bacteria. [ABSTRACT FROM AUTHOR]

Constructing safe and effective antibacterial surfaces has continuously received great attention, especially in healthcare-related fields. Bioinspired mechano-bactericidal nanostructure surfaces could serve as a promising strategy to reduce surface bacterial contamination while avoiding the development of antibiotic resistance. Although effective, these nanostructure surfaces are prone to be contaminated by the accumulation of dead bacteria, inevitably compromising their long-term antibacterial activity. Herein, a bioinspired nanopillar surface with both mechano-bactericidal and releasing actions is developed, via grafting zwitterionic polymer (poly(sulfobetaine methacrylate) (PSBMA)) on ZnO nanopillars. Under dry conditions, this nanopillar surface displays remarkable mechano-bactericidal activity, because the collapsed zwitterionic polymer layer makes no essential influence on nanopillar structure. Once being incubated with aqueous solution, the surface could readily detach the killed bacteria and debris, owing to the swelling of the zwitterionic layer. Consequentially, the surface antibacterial performances can be rapidly and controllably switched between mechano-bactericidal action and bacteria-releasing activity, guaranteeing a long-lasting antibacterial performance. Notably, these collaborative antibacterial behaviors are solely based on physical actions, avoiding the risk of triggering bacteria resistance. The resultant nanopillar surface also enjoys the advantages of substrate-independency and good biocompatibility, offering potential antibacterial applications for biomedical devices and hospital surfaces. [Display omitted] • A bioinspired nanopillar surface (ZnO-PSBMA) was designed. • ZnO-PSBMA played switchable mechano-bactericidal and releasing actions. • These antibacterial behaviors were solely based on physical actions, avoiding the risk of triggering bacteria resistance. • ZnO-PSBMA nanopillar showed substrate-independency and good biocompatibility. [ABSTRACT FROM AUTHOR]

Abstract: Sedimentary sequences occurring in desert dunes reflect changes in desert systems, and as such may contain signals useful for recognizing spatial and temporal changes of deserts and their response to regional or even global climate fluctuations. Geomorphological and palaeoenvironmental studies within the dune fields of the Asian middle-latitudes have provided some solid evidence for interpreting the history of these sand seas. Using the Hunshandake (Otindag) Sandy Land, a sandy area covered primarily by stabilized dunes and located in the semi-arid zone of eastern Inner Mongolia, China (Fig. 1), as an example, we studied the initiation and variation in the dune landscape in the eastern portion of the desert belt in northern China. On the basis of physical and biochemical indicators in the sediments and OSL chronology, we herein argue that this dune system in the middle latitudes of eastern Asia is much younger than previously assumed and that it has responded sensitively to climate change during the late Quaternary. Geological evidence from the Sandy Land suggests that most of the current dunes are of late Pleistocene or even Holocene age. Palaeosols intercalated in the aeolian sequences and their OSL chronology show that the climate of the Hunshandake was much wetter than today between 9.6 ka and 3 ka. This resulted in stabilization of the dunes in the eastern and central portions of the Sandy Land. Epochs of reworking or stabilization of the dunes are broadly consistent with the fluctuations in northern hemisphere solar radiation although with an obvious time lag. Because the increase rate of annual precipitation was not sufficient to fully stabilize the dunes in more arid part of the region, some active dunes persisted even during this long-lasting wetter epoch. We conclude that periods of Holocene dune stabilization due to palaeosol formation varied along the climate gradients across the various sandy lands of northern China, and in general it began earlier and lasted longer in the east than in the west. The general nature of the sandy lands and their counterparts in the western portion of the desert belt during the LGM and mid-Holocene climate optimum is discussed in comparison with their current states. [Copyright &y& Elsevier]

Sema4D, a member of the immune semaphorin family, plays crucial roles in the immune regulation, bone resorption and nervous system. It is also involved in angiogenesis and tumour progression. However, systemic studies on the correlation between Sema4D expression and the immune infiltration or clinical outcomes in tumours are still limited. Here, we analysed the landscape of Sema4D expression and its prognostic value in the cancer genome atlas pan-cancer as well as the correlation between Sema4D and immune cell infiltration by Tumour Immune Estimation Resource and Gene Expression Profiling interactive analysis online tools. Results showed that a higher Sema4D expression was significantly correlated with a favourable overall survival in diverse solid tumours including bladder cancer (Hazards Ratio (HR)=0.68, p =.0095), kidney renal clear cell carcinoma (HR = 0.61, p =.0016), melanoma (HR = 0.58, p = 6.6e-05) and thymoma (HR = 0.1, p =.011). Interestingly, Sema4D expression has positive correlation with various tumour infiltrating immune cells and immune cell biomarkers in these tumours. These results suggest that Sema4D could be a prospective biomarker for calculating hazard ratio of tumour patients and their tumour immune infiltration levels. [ABSTRACT FROM AUTHOR]

Developing highly active nonprecious electrocatalysts with superior durability for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial to improve the efficiency of overall water splitting but remains challenging. Here, a novel superhydrophilic Co4N‐CeO2 hybrid nanosheet array is synthesized on a graphite plate (Co4N‐CeO2/GP) by an anion intercalation enhanced electrodeposition method, followed by high‐temperature nitridation. Doping CeO2 into Co4N can favor dissociation of H2O and adsorption of hydrogen, reduce the energy barrier of intermediate reactions of OER, and improve the compositional stability, thereby dramatically boosting the HER performance while simultaneously inducing enhanced OER activity. Furthermore, the superhydrophilic self‐supported electrode with Co4N‐CeO2 in situ grown on the conductive substrate expedites electron conduction between substrate and catalyst, promotes the bubble release from electrode timely and impedes catalyst shedding, ensuring a high efficiency and stable working state. Consequently, the Co4N‐CeO2/GP electrode shows exceptionally low overpotentials of 24 and 239 mV at 10 mA cm−2 for HER and OER, respectively. An alkaline electrolyzer by using Co4N‐CeO2/GP as both the cathode and anode requires a cell voltage of 1.507 V to drive 10 mA cm−2, outperforming the Pt/C||RuO2 electrolyzer (1.540 V@10 mA cm−2). More significantly, the electrolyzer has extraordinary long‐term durability at a large current density of 500 mA cm−2 for 50 h, revealing its potential in large‐scale applications. [ABSTRACT FROM AUTHOR]

The Kubuqi Desert is the only active sand sea in the semiarid regions of northern China and occurs along the southern margin of the Yellow River. Little is known about the age and origin of this large (17,000 km 2 ) sand sea with a present annual precipitation of 200‐480 mm. Sand drift potentials indicated net capable winds for aeolian transport are from the northwest, though winds are stronger to north beyond the dune field than within the sand sea. Geomorphic and stratigraphic observations indicate that Holocene aeolian sand often drapes over bedrock and river terraces as a palimpsest landscape. Field investigations identified four stratigraphic sections with multiple aeolian sand units and palaeosols, with age control by optically stimulated luminescence (OSL) dating of quartz grains. Palaeosols are weakly developed, mostly accumulative A horizon with organic carbon content < 1% and reflect sand sheet deposition possibly in a steppe environment. Although sediments near river channels or former lakes might give old ages, the initial formation and age of the Kubuqi sand sea should be judged from the occurrence of the sandy palimpsest of the landscape that is OSL dated to the Holocene in general. The latest period of aeolian reactivation may be related to human activity associated with grazing and farming from lost cities in the Kubuqi Desert during the Han (206 B.C. – A.D. 220) and the Tang (A.D. 608 – 907) Dynasties. Also, variable discharge of the Yellow River with local diversions for irrigation and throughout the catchment resulted in possibly an increased supply of aeolian particles for dune field expansion in the past 2 ka. [ABSTRACT FROM AUTHOR]

Summary: Rivers draining the sedimentary platform of northern Xinjiang (the center of Asian continent) are characterized by low discharge under a temperate and arid climate. The influence of rock mineralogy, climate, relief and human activity on natural water composition and export as a result of weathering is a major scientific concern both at the local and the global scale. While comprehensive work on the controlling mechanism of chemical weathering has been less carried out in the sedimentary platform of northern Xinjiang. Thus, the effects of climate and rock weathering on the inorganic hydrogeochemical processes are not well quantified at this climatic extreme. To remedy this lack a comprehensive survey has been carried out of the geochemistry of the large, pristine rivers in northern Xinjiang, the Erlqis, Yili, Wulungu, Jingou and numerous lesser streams which has not experienced the pervasive effects of glaciation and subsequent anthropogenic impacts. The scale of the terrain sampled, in terms of area, is comparable to that of the Huanghe and includes a diverse range of geologic and climatic environments. In this paper the chemical fluxes from the stable sedimentary basin of the northern Xinjiang platform will be presented and compared to published results from analogous terrains in the monsoon basins of China and world. Overall, the fluvial geochemistry of northern Xinjiang in westerly climate is similar to that of the Chinese rivers (Huanghe and Yangtze) in the East-Asian monsoon Climate, both in property–property relationships and concentration magnitudes. The range in the chemical signatures of the various tributaries is large; this reflects that lithology exerts the dominant influence in determining the weathering yield from the sedimentary terrains rather than the weathering environment. The effect of different rock weathering ranges from rivers dominated by aluminosilicate weathering, mainly of granites, sandstones and shales, to those bearing the signatures of dissolution of carbonates and evaporites and of continental playa deposits. Carbonates are the general predominant lithology undergoing dissolution particularly within the lesser arid areas. The pCO2 in the study rivers is out of equilibrium with respect to atmospheric pCO2, about up to ∼20 times supersaturated relative to the atmosphere but not to such an extent as the Amazon in the floodplain. A roughly positive relationship is observed between solute concentrations and the drought index (DI) for natural waters in the region, indicating a coupled mountain-basin climate has a direct effect. The relative contributions of end-member solute sources to the total dissolved cations from each watershed have been quantitatively estimated using dissolved load balance models, showing the results as evaporite dissolution>carbonate weathering>silicate weathering>atmospheric input for the whole catchment. The areal total dissolved fluxes range from 0.05 to 2.53×106 mol/km2/yr, 0.02–2.09×106 mol/km2/yr and 0.01–1.04×106 mol/km2/yr in the Yili, Zhungarer and Erlqis, respectively, comparable to those of Chinese and Siberia rivers draining sedimentary platforms, even though they are in drastically different climatic regimes. In general, the fluxes from rivers in sedimentary basins are comparable to those from orogenic zones, but are much higher than in the shield regions. The CO2 consumption by aluminosilicate weathering (0.2–284×103 mol/km2/yr) is much smaller than in active orogenic belts (19–1750×103 mol/km2/yr in similar latitudes and 143–1000×103 mol/km2/yr in the tropical basins), but comparable to those of the Chinese (7–106×103 mol/km2/yr) and Siberia (16–112×103 mol/km2/yr) rivers. [Copyright &y& Elsevier]

Abstract: Chemical weathering is an integral part of the earth surface processes, whose spatial patterns and controlling factors on continental scale are still not fully understood. Highlands of the Asian continent have been shown having some of the highest observed rates of chemical weathering yet reported. However, the paucity of river gauge data in many of these terrains has limited determination of chemical weathering budget in a continental scale. A dataset of three large watersheds throughout northern Xinjiang in Central Asia is used to empirically identify chemical weathering regimes and interpret the underlying controlling factors. Detailed analysis of major ion ratios and a forward model of mass budget procedure are presented to distinguish the relative significances and contributions of silicate, carbonate weathering and evaporite dissolution. The analytical results show that carbonic acid is the most important weathering agent to the studied watersheds. Silicate weathering contributes, on average, ∼17.8% (molar basis) of total cations on a basin wide scale with an order of Zhungarer>Erlqis>Yili, indicating that silicate weathering, however, does not seem to be intense in the study basins. Evaporite dissolution, carbonate weathering and precipitation input contribute 43.6%, 29.7% and 8.9% of the total dissolved cations on average for the whole catchment, respectively. The three main morphological and hydrological units are reflected in water chemistry. Rivers from the montane areas (recharge area) of the three watersheds are very dilute, dominated by carbonate and silicate weathering, whereas the rivers of piedmont areas as well as the rivers of the sedimentary platform (runoff area) are dominated by carbonate weathering, and rivers of desert plain in the central Zhungarer basin (discharge area) are dominated by evaporite dissolution and are SO4 rich. This spatial pattern indicates that, beside lithology, runoff conditions have significant role on the regional chemical weathering regimes. Chemical weathering processes in the areas appear to be significantly climate controlled, displaying a tight correlation with runoff and aridity. Carbonate weathering are mostly influenced by runoff, which is higher in the mountainous part of the studied basins. The identification of chemical weathering regimes from our study confirmed the weathering potential and complexity of temperate watersheds in arid environment and that additional studies of these terrains are warranted. However, because the dominant weathering reactions in the sedimentary platform of northern Xinjiang are of carbonates and evaporites rather than silicate minerals, and the climatic factors have important role on the rock weathering regimes, we think that weathering at the arid temperate drainage system (Central Asia) is maybe not an important long-term sink for atmospheric CO2, if the future climate has no great change. [Copyright &y& Elsevier]

We report a rare case of right retrocaval ureter and left nutcracker syndrome in a young man who was accurately diagnosis preoperatively with the help of intravenous urogram and gray-scale and color flow Doppler ultrasonography, and confirmed by computed tomography. Surgery that involves resection of the retrocaval segment and relocation of the anastomosis anterior to the inferior vena cave was performed for the right retrocaval ureter, whereas surveillance was adopted for the left nutcracker syndrome. [Copyright &y& Elsevier]

Abstract: This paper reviews our current understanding of Quaternary climate and landscape changes in the desert areas of northern China, a key portion of the middle-latitude drylands on Earth. Combining earlier studies with our recent research and experience, we offer a comprehensive picture of the state of Chinese deserts during the Quaternary and, in the interest of enhancing future research, identify knowledge gaps and areas of uncertainty. Lacustrine deposits found over an area ranging from China’s western Taklamakan Desert to the eastern Hunshandake Sandy Lands suggest that extensive lakes occurred in China’s deserts during the Pleistocene. Analysis of digital elevation models from SRTM (Shuttle Radar Topography Mission) data supports this interpretation and shows the significant extent of these former lakes. New estimates of mean annual evaporation of ca. 1000 mm from lake surfaces and ca. 100 mm from land surfaces, confirms that local and regional rainfall is critical for maintenance of desert lakes in this temperate zone, especially during intervals when the mean annual rainfall is more than 100 mm. Rapid shifts between sand seas and lakes in geologically and environmentally diverse settings suggest that the drylands of China are very sensitive ephemeral systems, and not long-lasting as previously thought. Available chronologies suggest that there were large lakes in the western Taklamakan Desert and the Chadamu Basin during MIS (Marine Isotope Stage) 3, at ∼30 ka, probably related to a period of strong influence of northern hemispheric westerly winds. Channels and elevation models revealed by SRTM data and remains of lacustrine sediments also indicate that there was a large lake in the Hunshandake Sandy Lands in the eastern portion of the desert belt during the Quaternary. There is significant evidence that during the middle Holocene strong summer monsoons led to a relatively large increase in moisture availability in the entire desert belt of northern China. Lacustrine records from the Badain Jaran Desert in western Inner Mongolia suggest that it was generally dry before 10 cal ka, becoming wetter from 10 to 4 cal ka, and dry again afterwards. Study of palaeosols widely occurring in dune stratigraphy in the eastern portion of the desert belt, suggests that there was a period of wet and warm climate in this region during the mid-Holocene Optimum, at a minimum between 6 ka and 4 ka, but possibly lasting longer. Recent observations dealing with the generation and transport of dust from Central Asia indicate that the causal relationship between sand seas and loess sequences is not as close as previously assumed. These results suggest that there is an urgent need to examine whether the frequency and amplitude of climatic variation in Chinese deserts are somehow similar to that having occurred in the Sahara Desert of North Africa. Deserts in northern China were also important focal regions for Neolithic cultures during intervals when environmental conditions supported a denser vegetative cover. There is evidence that some areas of woody vegetation to the west of Badain Jaran Desert were deforested by humans by ca. 4000 yr B P, although it is still debatable whether humans have had a significant impact in other areas at that time. Opinions on the severity of desertification vary and are sometimes contradictory due to the lack of long-term, field-based, investigations. [Copyright &y& Elsevier]

Abstract: In the arid region of northern Xinjiang, one of the least-studied areas in China, three watersheds, namely those of the Yili, Zhungarer and Erlqis, have become the focus of attention due to rapidly increasing human population and water demands. The hydrogeochemistry of natural water from the three watersheds was investigated. The ionic chemistry of natural waters from these watersheds changes considerably on a regional scale. The waters are neutral to alkaline in nature and most of them are soft-fresh waters. The total dissolved solid (TDS) varies over two orders of magnitude with a mean value of 580mg/L, about 1.2 times and 4.6 times those of the Huanghe (Yellow River) and the world spatial median, respectively, but only 40% and 0.8% of those of the Tarim and the western Alashan watersheds, respectively. Much of the solutes and physicochemical parameters in these waters are under the highest desirable limits of the World Health Organization (WHO) for drinking purpose and a plot of sodium adsorption ratio versus EC shows that most waters are of good water quality for irrigation. Water–rock interaction and saturation index (SI) for selected minerals are evaluated. The SI of these natural waters is out of equilibrium (undersaturated) with respect to major carbonates (calcite and dolomite) and evaporites (gypsum and halite). The high concentrations of alkali earth metals, alkalinity and the high (Ca+Mg)/(Na+K) and Na/Cl ratios indicate that the release of major solutes in these waters is controlled largely by dissolution processes of carbonate and partly by silicate weathering, while, cation exchange reactions, soil–salt leaching and evaporation processes also play an important role. The effects of local pollution are minimal in the montane and piedmont areas of these watersheds but are significant in the oases and central areas of the drainage basins. [Copyright &y& Elsevier]

Objectives: To report our experience in the diagnosis and surgical treatment of the nutcracker syndrome, which is uncommon, with few larger series published. Methods: We retrospectively analyzed 23 patients with the nutcracker syndrome who presented to our institution from July 1998 to July 2007. A diagnosis of the nutcracker syndrome was suspected from the clinical examination, ultrasound, computed tomography, and magnetic resonance imaging findings. The diagnosis was confirmed by determination of the renocaval gradient using phlebography of the left renal vein (LRV). Because of recurrent gross hematuria and persistent orthostatic proteinuria, 7 patients (4 females and 3 males) underwent LRV transposition. Other patients with mild and tolerable symptoms were treated conservatively. The follow-up range was 14-122 months (mean 42.6). Results: All 23 patients met the criteria for establishing the diagnosis of the nutcracker syndrome. Ultrasonography, computed tomography, and magnetic resonance imaging revealed entrapment of the LRV between the superior mesenteric artery and aorta. The renocaval pressure gradient was ≥4 mm Hg (normal <1 mm Hg) in all patients. The hematuria and proteinuria disappeared in the 7 patients who underwent LRV transposition, and only 1 patient continued to have pelvic pain. No complications occurred during surgery. The postoperative complications included paralytic ileus in 2 and retroperitoneal hematoma in 1 patient. No improvement or only partial improvement was observed in most patients receiving conservative treatment. Conclusions: The diagnosis of the nutcracker syndrome is determined from the clinical examination and radiographic findings. In patients who require surgical treatment, LRV transposition is an efficient surgical approach with an acceptable risk of complications. However, in some cases, pelvic pain may persist despite removal of the obstruction of the renal venous backflow. [Copyright &y& Elsevier]