A seasonal drought forecasting approach using a high‐resolution meteorological forcing and hydrologic model was developed in the Mekong River Basin (MRB), where ground‐based observations are sparse. ...The Soil and Water Assessment Tool (SWAT) model was used to simulate soil moisture, runoff and evapotranspiration, which were then used to compute three drought indices for historical drought assessment (1953–2016) and seasonal forecasting of drought. In the absence of observed soil moisture data, SWAT was first calibrated with streamflow data to derive reliable soil moisture estimates, and historical drought events were validated with the available reference drought index. Based on the calibrated results, the Modified Palmer Drought Severity Index (MPDSI), Standardized Soil Moisture Index (SSI) and Multivariate Standardized Drought Index (MSDI) were estimated to evaluate the meteorological, agricultural and multivariate aspects, respectively, of drought. The total drought durations were 105–220 months, according to the reference drought index, and the estimated drought index captured 60–76% of these drought events. The three drought indices perform somewhat differently, but the 1991–1994 and 2015–2016 droughts were the worst drought events in the last 64 years based on analysis of the severity, duration and area of the meteorological and multivariate aspects of drought. The extreme droughts occurred in the Upper and Mid sections of the Lower Mekong sub‐basins and the 3S region when there were consecutive precipitation and temperature anomalies that continued for more than 2 years. Spatial variability in precipitation deficits and temperature increases were random because these variables affect soil moisture differentially. In addition, 68.4–76.1% of the areas with increased drought were explained by the areas' precipitation decrease or temperature increase. Validation of the multiple drought indices at high resolution can inform sub‐regional variability in drought conditions and hence food and water security in this important transboundary basin.
A seasonal drought forecasting approach was developed in the Mekong River Basin (MRB). The Soil and Water Assessment Tool (SWAT) model was used to generate three drought indices. The results demonstrated the 1991–1994 and 2015–2016 droughts were the worst in the last 64 years. The extreme droughts occurred in the Upper and Mid sections of the Lower Mekong sub‐basins and the 3S region. Also, 68.4–76.1% of the areas experienced increased drought.
The Lower Mekong River basin (LMB) has experienced droughts in recent decades, causing detrimental economic losses and food security conundrums. This study quantified the impact of climate change on ...drought, and rainfed rice production in the LMB. The Soil and Water Assessment Tool (SWAT) and AquaCrop models were used to evaluate long-term drought indices and rainfed rice yields under historical and future climate conditions (1954-2099) with four climate models and two emission scenarios (RCP 4.5 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We found that rice yield might increase (24-43%) due to the elevated levels of atmospheric CO
concentration (+ 34.3 to + 121.9%) and increases in precipitation. Contrastingly, considerable decreases in rice yield up to 1.5 ton/ha in the Vietnam Central High Plain (VCHP) region could be expected resulting from reduced precipitation by about 34% during drought years. To avert any major food crisis, an expansion of irrigation areas could be required to compensate for the expected reduction in rice yields. We conclude that a framework combining hydrology and crop models to assess climate change impacts on food production is key to develop adaptation strategies in the future.
•The drought conditions and their occurrences were determined at river basin scales.•The ensemble mean of SSI indicated an overall increase in agricultural drought occurrences.•MSDI and MPDSI ...exhibited a decrease in the future, despite increases in precipitation.•Hybrid-modeling approaches that consider both precipitation and temperature is desirable.
Virginia, United States.
Climate change is expected to impact the intensity and severity of droughts; therefore, it is necessary to simulate future drought conditions using temperature and precipitation projections and hydrological models to derive reliable hydrological variables and drought indices. The objective of this study was to evaluate climate change influences on future drought potential and water resources in five major river basins in Virginia. In this study, the Soil and Water Assessment Tool (SWAT) and Coupled Model Intercomparison Project Phase 5 (CMIP5) climate models were used to compute a Standardized Soil Moisture Index (SSI), a Multivariate Standardized Drought Index (MSDI), and a Modified Palmer Drought Severity Index (MPDSI) for both historic and future periods. The drought conditions were evaluated, and their occurrences were determined at river basin scales.
The results of the ensemble mean of SSI indicated that there was an overall increase in agricultural drought occurrences projected in the New (>1.3 times) and Rappahannock (>1.13 times) river basins due to increases in evapotranspiration and surface and groundwater flow. However, MSDI and MPDSI exhibited a decrease in projected future drought, despite increases in precipitation, which suggests that it is essential to use hybrid-modeling approaches and to interpret application-specific drought indices that consider both precipitation and temperature changes.
The ongoing and proposed construction of large-scale hydropower dams in the Mekong river basin is a subject of intense debate and growing international concern due to the unprecedented and ...potentially irreversible impacts these dams are likely to have on the hydrological, agricultural, and ecological systems across the basin. Studies have shown that some of the dams built in the tributaries and the main stem of the upper Mekong have already caused basin-wide impacts by altering the magnitude and seasonality of flows, blocking sediment transport, affecting fisheries and livelihoods of downstream inhabitants, and changing the flood pulse to the Tonle Sap Lake. There are hundreds of additional dams planned for the near future that would result in further changes, potentially causing permanent damage to the highly productive agricultural systems and fisheries, as well as the riverine and floodplain ecosystems. Several studies have examined the potential impacts of existing and planned dams but the integrated effects of the dams when combined with the adverse hydrologic consequences of climate change remain largely unknown. Here, we provide a detailed review of the existing literature on the changes in climate, land use, and dam construction and the resulting impacts on hydrological, agricultural, and ecological systems across the Mekong. The review provides a basis to better understand the effects of climate change and accelerating human water management activities on the coupled hydrological-agricultural-ecological systems, and identifies existing challenges to study the region’s Water, Energy, and Food (WEF) nexus with emphasis on the influence of future dams and projected climate change. In the last section, we synthesize the results and highlight the urgent need to develop integrated models to holistically study the coupled natural-human systems across the basin that account for the impacts of climate change and water infrastructure development. This review provides a framework for future research in the Mekong, including studies that integrate hydrological, agricultural, and ecological modeling systems.
Postoperative spinopelvic changes are associated with increased dislocation risk following total hip arthroplasty (THA). The aim of this study was to identify preoperative patient and radiographic ...factors associated with high‐risk postoperative spinopelvic parameters. A retrospective review of consecutive THA patients who received preoperative and postoperative sitting and standing lateral lumbar spine‐hip radiographs with minimum radiographic and clinical follow‐up of 10 months was performed. Patient demographics were recorded and preoperative standing and sitting sacral slope (SS), anteinclination, pelvic femoral angle (PFA), and combined sagittal index (CSI) were measured. High‐risk patients were defined by decreased spinopelvic motion (∆SS from sitting to standing of >10°), increased hip motion (∆PFA from sitting to standing of >10°), or decreased CSI of >10° at final follow‐up compared with preoperative measurements. Univariate and multivariate regression analyses were used to identify preoperative demographic and radiographic factors associated with these high‐risk categories. One hundred and fifty‐three patients were included with an average age of 62 years, average body mass index of 27.8 kg/m2, and average follow‐up of 16.2 months. At 1‐year follow‐up, 43 (28.1%) patients demonstrated a decreased ∆SS > 10° and 67 (43.7%) patients demonstrated an increased ∆PFA > 10° compared with preoperative values. Sitting CSI decreased by >10° in 17 (11.1%) patients. Preoperative increased sitting PFA (adjusted odds ratio aOR 1.057, p < 0.001) and decreased preoperative hip motion (∆PFA) were associated with decreased sitting CSI of >10° at 10‐month follow‐up. Increased spinopelvic motion (∆SS) and decreased hip motion (∆PFA) preoperatively are associated with postoperative radiographic changes that be associated with increased dislocation risk.
Selenoprotein P (SELENOP), secreted from the liver, functions as a selenium (Se) supplier to other tissues. In the brain, Se homeostasis is critical for physiological function. Previous studies have ...reported that SELENOP co-localizes with the apolipoprotein E receptor 2 (ApoER2) along the blood–brain barrier (BBB). However, the mechanism underlying SELENOP transportation from hepatocytes to neuronal cells remains unclear. Here, we found that SELENOP was secreted from hepatocytes as an exosomal component protected from plasma kallikrein-mediated cleavage. SELENOP was interacted with apolipoprotein E (ApoE) through heparin-binding sites of SELENOP, and the interaction regulated the secretion of exosomal SELENOP. Using in vitro BBB model of transwell cell culture, exosomal SELENOP was found to supply Se to brain endothelial cells and neuronal cells, which synthesized selenoproteins by a process regulated by ApoE and ApoER2. The regulatory role of ApoE in SELENOP transport was also observed in vivo using ApoE
−/−
mice. Exosomal SELENOP transport protected neuronal cells from amyloid β (Aβ)-induced cell death. Taken together, our results suggest a new delivery mechanism for Se to neuronal cells by exosomal SELENOP.
The Mekong River Basin (MRB) is one of the significant river basins in the world. For political and economic reasons, it has remained mostly in its natural condition. However, with population ...increases and rapid industrial growth in the Mekong region, the river has recently become a hotbed of hydropower development projects. This study evaluated these changing hydrological conditions, primarily driven by climate as well as land use and land cover change between 1992 and 2015 and into the future. A 3% increase in croplands and a 1–2% decrease in grasslands, shrublands, and forests was evident in the basin. Similarly, an increase in temperature of 1–6 °C and in precipitation of 15% was projected for 2015–2099. These natural and climate-induced changes were incorporated into two hydrological models to evaluate impacts on water budget components, particularly streamflow. Wet season flows increased by up to 10%; no significant change in dry season flows under natural conditions was evident. Anomaly in streamflows due to climate change was present in the Chiang Saen and Luang Prabang, and the remaining flow stations showed up to a 5% increase. A coefficient of variation <1 suggested no major difference in flows between the pre- and post-development of hydropower projects. The results suggested an increasing trend in streamflow without the effect of dams, while the inclusion of a few major dams resulted in decreased river streamflow of 6% to 15% possibly due to irrigation diversions and climate change. However, these estimates fall within the range of uncertainties in natural climate variability and hydrological parameter estimations. This study offers insights into the relationship between biophysical and anthropogenic factors and highlights that management of the Mekong River is critical to optimally manage increased wet season flows and decreased dry season flows and handle irrigation diversions to meet the demand for food and energy production.
The primary objective of this study was to compare incidence, demographic trends, and rates of subsequent fusion between proximal row carpectomy (PRC) and 4-corner fusion (4CF) among patients in the ...United States.
A total of 3,636 patients who underwent PRC and 5,047 who underwent 4CF were identified from the years 2005 through 2014 among enrollees in the PearlDiver database. Regional distribution, demographic characteristics, annual incidence, comorbidities, and subsequent wrist fusion were compared between the 2 groups. Of the patients identified, 3,512 from each group were age- and sex-matched and subsequently compared for rates of converted fusion, 30- and 90-day readmission rates, and average direct cost.
Patients undergoing 4CF and PRC did not have statistically significant differences in comorbidities. The incidence of the procedures among all subscribers increased for both PRC (1.8 per 10,000 to 2.6 per 10,000) and 4CF (1.2 per 10,000 to 2.0 per 10,000) from 2005 to 2014. Comparing the matched cohorts, patients who underwent 4CF had a higher rate of subsequent fusion than those who underwent PRC (2.67% vs 1.79%). Readmission rates were not significantly different at 30 or 90 days. Average direct cost was significantly greater for 4CF than for PRC.
Both PRC and 4CF have been utilized at increasing rates in the past decade. Wrist fusion rates and average costs are higher in the 4CF group without a significant difference in readmission rates.
Therapeutic III.
Background:
No previous systematic review has focused on the athletes who fail to return to sport after hip arthroscopy for femoroacetabular impingement syndrome (FAIS).
Purpose:
To review the ...literature on the athletes who fail to return to sport after hip arthroscopy for FAIS to determine the rate of nonreturning athletes and explore the reasons for their inability to return to sport after arthroscopic FAI surgery.
Study Design:
Systematic review and meta-analysis.
Methods:
Three electronic databases were searched for eligible articles. Two reviewers independently screened the titles, abstracts, and full-text articles using prespecified criteria. Eligible articles were those that clearly stated the rate of athletes who did not return to sport after hip arthroscopy for FAIS. Data collected were the rate of patients who did not return to sport, the level of competition (high level, recreational, or mixed), the type of sport, comments on patients who did not return to sport, the rate of subsequent hip surgeries (total hip replacement or revision hip arthroscopy) in nonreturning athletes, and the reported reason for not returning to sport. A random-effects model was used for meta-analysis.
Results:
Twenty studies were eligible for inclusion, and 1093 athletes were analyzed. The weighted rate of athletes who did not return to sport after hip arthroscopy for FAIS was 12.1% (95% CI, 7.7-17.4). Only 2 studies (2/20;10%) reported the age of the athletes who did not return, while sex was reported in 3 studies (3/20;15%). The estimated proportion of athletes who did not return to sport because of hip-related issues was significantly greater than the percentage of athletes who did not return for reasons unrelated to their hip (74.3% vs 22.3%; P < .0001). Persistent hip pain was the most commonly reported factor (52/110 patients; 47.2%) associated with failure to return to sport. Whether the nonreturning athletes underwent any subsequent hip procedure after hip arthroscopy for FAIS was reported in only 4 out of 20 studies (20%). There was evidence of publication bias and study heterogeneity.
Conclusion:
The estimated rate of athletes who did not return to sport after hip arthroscopy for FAIS was 12%, with the majority of athletes being unable to return because of persistent hip pain. There is a severe lack of evidence on the athlete characteristics and clinical course of the nonreturning athletes, and the rate of subsequent hip procedures is unknown. The outcomes and reasons for athletes not returning to sport should be reported in detail to improve patient care.
The treatment of complex bone loss scenarios remains challenging. This study evaluates the efficacy of ex vivo regional gene therapy using transduced human adipose-derived stem cells (ASCs) ...overexpressing bone morphogenetic protein-2 (BMP-2) to treat critical-sized bone defects.
Critical-sized femoral defects created surgically in immunocompromised rats were treated with ASCs transduced with a lentivirus encoding BMP-2 (Group 1, n = 14), or green fluorescent protein (Group 2, n = 5), nontransduced ASCs (Group 3, n = 5), or rhBMP-2 (Group 4, n = 14). At 12 weeks, femurs were evaluated for quantity and quality of bone formation with plain radiographs, micro-computed tomography, histology/histomorphometry, and biomechanical strength testing.
Thirteen of 14 samples in Group 1 and all 14 samples in Group 4 showed radiographic healing, while no samples in either Groups 2 or 3 healed. Groups 1 and 4 had significantly higher radiographic scores (p < 0.001), bone volume fraction (BV/TV) (p < 0.001), and bone area fraction (BA/TA) than Groups 2 and 3 (p < 0.001). Radiographic scores, BV/TV, and BA/TA were not significantly different between Groups 1 and 4. No difference with regards to mean torque, rotation at failure, torsional stiffness, and energy to failure was seen between Groups 1 and 4.
Human ASCs modified to overexpress BMP-2 resulted in abundant bone formation, with the quality of bone comparable to that of rhBMP-2. This strategy represents a promising approach in the treatment of large bone defects in the clinical setting.
Large bone defects may require sustained protein production to induce an appropriate osteoinductive response. Ex vivo regional gene therapy using a lentiviral vector has the potential to be part of a comprehensive tissue engineering strategy for treating osseous defects.
•Human adipose-derived stem cells can successfully be transduced to overexpress BMP2.•These transduced cells can regenerate bone in a critical-sized rat femoral defect.•The quality of regenerated bone is nearly equivalent to native bone.
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