Regional homogeneity alterations in patients with functional constipation and their associations with gene expression profiles.

Functional constipation, a highly prevalent functional gastrointestinal disorder, often accompanies by mental and psychological disorders. Previous neuroimaging studies have demonstrated brain functional and structural alterations in patients with functional constipation. However, little is known about whether and how regional homogeneity is altered in these patients. Moreover, the potential genetic mechanisms associated with these alterations remain largely unknown. The study included 73 patients with functional constipation and 68 healthy controls, and regional homogeneity comparison was conducted to identify the abnormal spontaneous brain activities in patients with functional constipation. Using Allen Human Brain Atlas, we further investigated gene expression profiles associated with regional homogeneity alterations in functional constipation patients with partial least squares regression analysis applied. Compared with healthy controls, functional constipation patients demonstrated significantly decreased regional homogeneity in both bilateral caudate nucleus, putamen, anterior insula, thalamus and right middle cingulate cortex, supplementary motor area, and increased regional homogeneity in the bilateral orbitofrontal cortex. Genes related to synaptic signaling, central nervous system development, fatty acid metabolism, and immunity were spatially correlated with abnormal regional homogeneity patterns. Our findings showed significant regional homogeneity alterations in functional constipation patients, and the changes may be caused by complex polygenetic and poly-pathway mechanisms, which provides a new perspective on functional constipation's pathophysiology.

The Effectiveness and Safety of Intrapartum or Postpartum Catheterization in the Prevention of Postpartum Urinary Retention: A Scoping Review.

INTRODUCTION AND HYPOTHESIS: Catheterization is a common treatment for postpartum urinary retention (PUR); however, its application before diagnosis of PUR remains unclear. The aim was to give an overview of the existing literature on the effectiveness and safety of intrapartum or postpartum catheterization in the prevention of PUR. METHODS: This scoping review followed a methodological framework. PubMed, the Cochrane Library, Embase, Web of Science, the China National Knowledge Infrastructure, WanFang, the China Science and Technology Journal Database, and the China Biomedical Literature Database were searched from the inception of each database to 21 May 2023. RESULTS: The search revealed 16 studies examining three different catheterization methodologies, including 12 intrapartum studies. Ten studies concluded that intrapartum or postpartum catheterization prevented PUR, two of which were only for overt or covert PUR. In 4 out of 13 experimental studies, no significant difference was found: one for intrapartum catheterization versus routine nursing, the other for intrapartum or postpartum intermittent versus indwelling catheterization. However, one found that postpartum disposable catheterization after ineffective targeted care reduced the incidence of PUR compared with indwelling catheterization. One out of the 3 case-control studies concluded that prenatal catheterization ≥2 times was a risk factor for PUR. CONCLUSIONS: Based on the findings in this scoping review, catheterization prior to the diagnosis of PUR appears to play a role in preventing PUR and is safe. Preliminary evidence is accumulating on the effectiveness of three types of catheterization methods in preventing PUR, but more comprehensive studies are needed to establish these findings.

Evaluation of left ventricular blood flow kinetic energy in patients with hypertension by four-dimensional flow cardiovascular magnetic resonance imaging: a preliminary study.

OBJECTIVES: To evaluate the intra-cavity left ventricular (LV) blood flow kinetic energy (KE) parameters using four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) in patients with hypertension (HTN). METHODS: Forty-two HTN patients and twenty age-/gender-matched healthy controls who underwent CMR including cines, pre-/post-T1 mapping, and whole-heart 4D flow imaging were retrospectively evaluated. HTN patients were further divided into two subgroups: with preserved ejection fraction (HTN-pEF) and with reduced ejection fraction (HTN-rEF). KE parameters were indexed to LV end-diastolic volume (EDV) to obtain averaged LV, minimal, systolic, diastolic, peak E-wave, peak A-wave, E-wave, and A-wave KEiEDV, as well as the proportion of in-plane LV KE (%), the time difference (TD). These parameters were compared between the HTN group and healthy controls, also between two subgroups. The correlation of LV blood flow KE parameters with LV function and extracellular volume fraction (ECV) were analyzed in the HTN group using multivariate regression analysis. RESULTS: Peak E-wave KEiEDV in the HTN group was significantly lower (p = 0.01), while in-plane KE and TD were significantly higher (all p < 0.01) than those in healthy controls. Compared to the HTN-pEF subgroup, the proportion of in-plane KE and TD was significantly increased in the HTN-rEF subgroup (all p < 0.01). Only the proportion of in-plane KE demonstrated an independent correlation with ECV (ß* = 0.59, p < 0.01). CONCLUSIONS: The decreased peak E-wave KEiEDV and the increased proportion of in-plane KE, TD reflected the alterations of LV blood flow in HTN patients, and the proportion of in-plane KE was independently associated with ECV. KEY POINTS: • 4D flow CMR demonstrated that the peak E-wave KEiEDV was decreased, while the in-plane KE and time difference (TD) were increased in hypertensive (HTN) patients. • The proportion of in-plane KE and TD was further increased in HTN patients with reduced ejection fraction than in HTN patients with preserved ejection fraction, and the proportion of in-plane KE was independently associated with extracellular volume fraction in HTN patients. • 4D flow CMR intra-cavity blood flow KE parameters might reveal the LV hemodynamic status in preclinical HTN patients.

Computationally guided discovery of novel non-steroidal AR-GR dual antagonists demonstrating potency against antiandrogen resistance.

As a major class of medicine for treating the lethal type of castration-resistant prostate cancer (PCa), long-term use of androgen receptor (AR) antagonists commonly leads to antiandrogen resistance. When AR signaling pathway is blocked by AR-targeted therapy, glucocorticoid receptor (GR) could compensate for AR function especially at the late stage of PCa. AR-GR dual antagonist is expected to be a good solution for this situation. Nevertheless, no effective non-steroidal AR-GR dual antagonist has been reported so far. In this study, an AR-GR dual binder H18 was first discovered by combining structure-based virtual screening and biological evaluation. Then with the aid of computationally guided design, the AR-GR dual antagonist HD57 was finally identified with antagonistic activity towards both AR (IC50 = 0.394 µM) and GR (IC50 = 17.81 µM). Moreover, HD57 could effectively antagonize various clinically relevant AR mutants. Further molecular dynamics simulation provided more atomic insights into the mode of action of HD57. Our research presents an efficient and rational strategy for discovering novel AR-GR dual antagonists, and the new scaffold provides important clues for the development of novel therapeutics for castration-resistant PCa.

mDIXON-Quant technique diagnostic accuracy for assessing bone mineral density in male adult population.

BACKGROUND: To investigate the diagnostic efficacy of mDIXON-Quant technique for prediction of bone loss in male adults. METHODS: One hundred thirty-eight male adults were divided into normal, osteopenia, and osteoporosis groups based on DXA and QCT for the lumbar spine. Differences in mDIXON-Quant parameters [fat fraction (FF) and T2* value] among three groups, as well as the correlation of mDIXON-Quant parameters and bone mineral density (BMD) were analyzed. The areas under the curves (AUCs) for mDIXON-Quant parameters for prediction of low bone mass were calculated. RESULTS: According to DXA standard, FF and T2* value were significantly increased in osteoporosis group compared with normal group (P = 0.012 and P < 0.001). According to QCT standard, FF was significantly increased in osteopenia and osteoporosis groups compared with normal group (both P < 0.001). T2* values were significantly different among three groups (all P < 0.05). After correction for age and body mass index, FF was negatively correlated with areal BMD and volumetric BMD (r = -0.205 and -0.604, respectively; both P < 0.05), and so was T2* value (r = -0.324 and -0.444, respectively; both P < 0.05). The AUCs for predicting low bone mass according to DXA and QCT standards were 0.642 and 0.898 for FF, 0.648 and 0.740 for T2* value, and 0.677 and 0.920 for both combined, respectively. CONCLUSIONS: FF combined with T2* value has a better diagnostic efficacy than FF or T2* value alone in prediction of low bone mass in male adults, which is expected to be a promising MRI method for the screening of bone quality. TRIAL REGISTRATION: ChiCTR1900024511 (Registered 13-07-2019).

The role of nature reserves in conservation effectiveness of ecosystem services in China.

Establishing nature reserves (NRs) is a common method to avoid biodiversity loss and degradation of ecosystem services (ESs). The evaluation of ESs in NRs and the exploration of associated influencing factors are the basis for improving ESs and management. However, the ES effectiveness of NRs over time remains questionable, namely due to the heterogeneity of landscape characteristics inside and outside of NRs. This study (i) quantifies the role of 75 NRs in China in maintaining ESs (i.e., net primary production (NPP), soil conservation, sandstorm prevention and water yield) from 2000 to 2020, (ii) reveals the trade-offs/synergies, and (iii) identifies the main influencing factors of the ES effectiveness of NRs. The results show that more than 80% of NRs had positive ES effectiveness, which was greater in older NRs. For different ESs, effectiveness over time increases for NPP (E_NPP), soil conservation (E_SC) and sandstorm prevention (E_SP) but declines for water yield (E_WY). There is a clear synergistic relationship between E_NPP and E_SC. Moreover, the effectiveness of ESs is closely correlated with elevation, precipitation, and perimeter area ratio. Our findings can provide important information to support site selection and management of reserves to improve the delivery of critical ecosystem services.

[Arsenic speciation and valence].

As arsenic widely exists in nature and has been used in the pharmaceutical preparations, the traditional Chinese medicine(TCM) with arsenic include realgar(As_2S_2 or As_4S_4), orpiment(As_2S_3), and white arsenic(As_2O_3). Among the above representative medicine, the TCM compound formulas with realgar are utilized extensively. Just in Chinese Pharmacopoeia(2020 edition), there are 37 Chinese patent medicines including realgar. The traditional element analysis focuses on the detection of the total amount of elements, which neglects the study on the speciation and valence of elements. The activity, toxicity, bioavailability, and metabolic pathways of arsenic in vivo are closely related to the existence of its form, and different forms of arsenic have different effects on organisms. Therefore, the study on the speciation and valence of arsenic is of great importance for arsenic-containing TCMs and their compound formulas. This paper reviewed four aspects of the speciation and valence of arsenic, including property, absorption and metabolism, toxicity, and analytical assay.

[Varieties systematization and standards status analysis of fermented Chinese medicine].

Fermented Chinese medicine has long been used. Amid the advance for preservation of experience, the connotation of fermented Chinese medicine has been enriched and improved. However, fermented Chinese medicine prescriptions generally contain a lot of medicinals. The fermentation process is complicated and the conventional fermentation conditions fail to be strictly controlled. In addition, the judgment of the fermentation end point is highly subjective. As a result, quality of fermented Chinese medicine is of great difference among regions and unstable. At the moment, the quality standards of fermented Chinese medicine are generally outdated and different among regions, with simple quality control methods and lacking objective safe fermentation-specific evaluation indictors. It is difficult to comprehensively evaluate and control the quality of fermented medicine. These problems have aroused concern in the industry and also affected the clinical application of fermented Chinese medicine. This article summarized and analyzed the application, quality standards, and the modernization of fermentation technology and quality control methods of fermented Chinese medicine and proposed suggestions for improving the quality standards of the medicine, with a view to improving the overall quality of it.

9-Bromo-2,3-diethylbenzo[de]chromene-7,8-dione (MSN54): A novel non-intercalative topoisomerase II catalytic inhibitor.

Novel mansonone F derivative MSN54 (9-bromo-2,3-diethylbenzo[de]chromene-7,8-dione) exhibited significant cytotoxicity against twelve human tumor cell lines in vitro, with particularly strong potency against HL-60/MX2 cell line resistant to Topo II poisons. MSN54 was found to have IC50 of 0.69 and 1.43 µM against HL-60 and HL-60/MX2 cells, respectively. The resistance index is 10 times lower than that of the positive control VP-16 (etoposide). Various biological assays confirmed that MSN54 acted as a Topo IIα specific non-intercalative catalytic inhibitor. Furthermore, MSN54 exhibited good antitumor efficacy and low toxicity at a dose of 5 mg/kg in A549 tumor xenograft models. Thus, compound MSN54 is a promising candidate for the development of novel antitumor agents.

Serum biomarkers combined with ultrasonography for early diagnosis of non-alcoholic fatty liver disease confirmed by magnetic resonance spectroscopy.

Magnetic resonance spectroscopy (MRS) is notably accurate for even minimal degree of hepatic steatosis in non-alcoholic fatty liver disease (NAFLD). But routine use of MRS is limited by its cost and availability. In this study, we developed a diagnostic model combining ultrasonography with biomarkers to identify mild NAFLD, with MRS as the reference standard. A total of 422 eligible subjects were enrolled. The serum levels of fibroblast growth factor 21 (FGF21), cytokeratin 18 M65ED, proteinase 3, neutrophil elastase, alpha-1 antitrypsin, and neutrophil elastase/alpha-1 antitrypsin were measured using ELISA assays. We found that among the six biomarkers, only serum FGF21 was independently associated with intrahepatic triglyceride content (IHTC, standardized ß = 0.185, P < 0.001) and was an independent risk factor for mild NAFLD. Thus, we established a Mild NAFLD Model based on FGF21, alanine transaminase, triglycerides, and body mass index. The area under the receiver-operating characteristic curve of the Mild NAFLD Model was 0.853 (95% confidence interval: 0.816-0.886). Furthermore, a two-step approach combining ultrasonography with the Mild NAFLD Model displayed a better sensitivity for diagnosing mild NAFLD compared with each method alone, with a sensitivity of 97.32% and a negative predictive value of 85.48%. This two-step approach combining ultrasonography and the Mild NAFLD Model derived from serum FGF21 improves the diagnosis of mild NAFLD and can be applied to the early diagnosis of NAFLD in clinical practice.

[Development of preparation process of icaritin-coix seed oil microemulsion based on quality by design concept].

To optimize the formulation and preparation process of icaritin-coix seed oil microemulsion(IC-MEs) based on quality by design(QbD) concept. IC-MEs were prepared by water titration. Firstly, the risk factors that may affect the quality of IC-MEs were evaluated. Then Plackett-Burman design was used to screen out prescription factors and process parameters that had a significant effect on the indicators. Finally, Box-Behnken design was used to optimize the prescription ratio of IC-MEs. Through the risk assessment and Plackett-Burman design, three formulation factors [drug loading efficiency, the ratio of mixed-oil(coix seed oil-Glycerol tributyrate) to mixed-surfactant(HS15-RH40) and water addition] were determined as the key factors affecting IC-MEs. The regression model established by Box-Behnken design had a good predictability. The optimal formula was as following: the drug loading efficiency of 0.92%, the ratio of mixed-oil(coix seed oil-glycerol tributyrate) to mixed-surfactant(HS15-RH40) of 4∶6, and the water addition of 5.7 mL. According to this prescription, IC-MEs were prepared, and its encapsulation efficiency after 1 week was 92.45%±1.00%. Therefore, the stability of IC-MEs could be improved by optimizing prescription and process parameters of IC-MEs based on the QbD concept, which can provide certain reference value for the future development of IC-MEs.

Copper-Catalyzed Double Thiolation To Access Sulfur-Bridged Imidazopyridines with Isothiocyanate.

A copper(I)-catalyzed sulfur-bridged dimerization of imidazopyridines has been developed using isothiocyanate as the sulfur source. This method enables a switchable synthesis of bis(imidazo[1,2- a]pyridin-3-yl)sulfanes or bis(2-(imidazo[1,2- a]pyridin-2-yl)phenyl)sulfanes in the presence of 4-dimethylaminopyridine (DMAP) or K2CO3 when different imidazopyridines were employed. Under optimized conditions, a variety of sulfur-bridged imidazopyridines were obtained in good yields. Moreover, thiourea was proved to be the key intermediate under catalytic system A.

Recent Advances in Enantioselective Photochemical Reactions of Stabilized Diazo Compounds.

Diazo compounds have proven to be a useful class of carbenes or metal carbenoids sources under thermal, photochemical, or metal-catalyzed conditions, which can subsequently undergo a wide range of synthetically important transformations. Recently, asymmetric photocatalysis has provoked increasing research interests, and great advances have been made in this discipline towards the synthesis of optically enriched compounds. In this context, the past two decades have been the most productive period in the developments of enantioselective photochemical reactions of diazo compounds due to a better understanding of the reactivities of diazo compounds and the emergence of new catalytic modes, as well as easier access to and treatment of stabilized diazo compounds. This review highlights these impressive achievements according to the reaction type, and the general mechanisms and stereochemical inductions are briefly discussed as well.

Attenuation of the hypoxia-induced miR-34a protects cardiomyocytes through maintenance of glucose metabolism.

Ischemic injury in the heart is associated with death of cardiomyocytes and even after decades of research there is no appropriate therapeutic intervention to treat ischemic injury. The microRNA miR-34a is known to be induced in cardiomyocytes following ischemic injury. Another hallmark of ischemic injury is impaired glycolysis. The objective of the current study was to investigate the effects of short- and long-term exposure to hypoxia on miR-34a expression on apoptosis and regulation of key glycolysis metabolic enzymes. Both repeated short-term (30 min) burst of hypoxia with intermittent reoxygenation (30 min) as well as long-term (4 h) exposure to hypoxia followed by 6 h of reoxygenation robustly induced miR-34a levels. Hypoxia induced changes in cardiac permeability and localization of the channel protein connexin 34 as well as induced apoptosis as evident by levels of cleaved-caspase 3/7 and impaired cell proliferation. Hypoxia was also associated with decreased expression of key glycolytic enzymes hexokinase-1, hexokinase-2, glucose-6-phosphate-isomerase, and pyruvate dehydrogenase kinase 1. Attenuation of hypoxia-induced miR-34a by anti-miR-34a antagomir, but not a control antagomir, decreased miR-34a levels to those observed under normoxia and also inhibited apoptosis, potentially by rescuing expression of the key glycolytic enzymes. Cumulatively, our results establish that therapeutic targeting of miR-34a via antagomir might be a potent therapeutic mechanism to treat ischemic injury in the heart.

Quantitative susceptibility mapping (QSM) minimizes interference from cellular pathology in R2* estimation of liver iron concentration.

BACKGROUND: A challenge for R2 and R2* methods in measuring liver iron concentration (LIC) is that fibrosis, fat, and other hepatic cellular pathology contribute to R2 and R2* and interfere with LIC estimation. PURPOSE: To examine the interfering effects of fibrosis, fat, and other lesions on R2* LIC estimation and to use quantitative susceptibility mapping (QSM) to reduce these distortions. STUDY TYPE: Prospective. PHANTOMS, SUBJECTS: Water phantoms with various concentrations of gadolinium (Gd), collagen (Cl, modeling fibrosis), and fat; nine healthy controls with no known hepatic disease, nine patients with known or suspected hepatic iron overload, and nine patients with focal liver lesions. FIELD STRENGTH/SEQUENCE: The phantoms and human subjects were imaged using a 3D multiecho gradient-echo on clinical 1.5T and 3T MRI systems. ASSESSMENT: QSM and R2* images were postprocessed from the same gradient-echo data. Fat contributions to susceptibility and R2* were corrected in signal models for LIC estimation. STATISTICAL TESTS: Polynomial regression analyses were performed to examine relations among susceptibility, R2* and true [Gd] and [Cl] in phantoms, and among susceptibility and R2* in patient livers. RESULTS: In phantoms, R2* had a strong nonlinear dependency on [Cl], [fat], and [Gd], while susceptibility was linearly dependent (R2 > 0.98). In patients, R2* was highly sensitive to liver pathological changes, including fat, fibrosis, and tumors, while QSM was relatively insensitive to these abnormalities (P = 0.015). With moderate iron overload, liver susceptibility and R2* were not linearly correlated over a common R2* range [0, 100] sec-1 (P = 0.35). DATA CONCLUSION: R2* estimation of LIC is prone to substantial nonlinear interference from fat, fibrosis, and other lesions. QSM processing of the same gradient echo MRI data can effectively minimize the effects of cellular pathology. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;48:1069-1079.

Reduction of Longitudinal Vertebral Blood Perfusion and Its Likely Causes: A Quantitative Dynamic Contrast-enhanced MR Imaging Study of a Rat Osteoporosis Model.

Purpose To determine the longitudinal relationships among lumbar vertebral blood perfusion, bone mass, and marrow adipose tissue in a rat osteoporosis model after ovariectomy by using quantitative dynamic contrast agent-enhanced (DCE) magnetic resonance (MR) imaging, microcomputed tomography (micro-CT), and proton MR spectroscopy. Materials and Methods In this animal review committee-approved study, lumbar vertebrae were evaluated through MR spectroscopy, quantitative DCE MR imaging, micro-CT, and histopathologic analysis, and blood was examined at 0, 2, 6, 10, 14, 18, and 24 weeks after ovariectomy consisting of exposure of the ovaries but no excision (n = 35) or sham operation, defined as exposure of the ovaries but no excision (n = 35). Differences in the parameters of these examinations between two groups at the same time point were analyzed by an independent-sample t test. Results Significantly reduced volume transfer constant (Ktrans) and volume of extravascular extracellular space per unit volume of tissue (week 2 and 10, respectively; P = .036 and P = .014, respectively), decreased bone mineral density (week 2; P = .014), and increased fat fraction (week 6; P = .036) in the ovariectomy group were observed, compared with those in the sham group. Vascular endothelial growth factor and microvessel density values of the ovariectomy group decreased significantly compared with those of the sham group from weeks 18 (P = .005) and 14 (P = .018), respectively. Transmission electron microscopy revealed tighter gaps among vascular endothelial cells and more marrow fibrosis in the ovariectomy group. Conclusion Quantitative DCE MR imaging can directly reflect marrow perfusion. Ktrans is a promising parameter to demonstrate early reduced marrow perfusion. Enhanced vasoconstriction and tightened gaps among vascular endothelial cells may be the likely causes in the initial stage of osteoporosis. Increased marrow adipose tissue, decreased microvessel density, and increased marrow fibrosis may aggravate marrow ischemia in the late stage of osteoporosis. © RSNA, 2016 Online supplemental material is available for this article.

Cleanable Air Filter Transferring Moisture and Effectively Capturing PM2.5.

The lethal danger of particulate matter (PM) pollution on health leads to the development of challenging individual protection materials that should ideally exhibit a high PM2.5 purification efficiency, low air resistance, an important moisture-vapor transmission rate (MVTR), and an easy-to-clean property. Herein, a cleanable air filter able to rapidly transfer moisture and efficiently capture PM2.5 is designed by electrospinning superhydrophilic polyacrylonitrile/silicon-dioxide fibers as the adsorption-desorption vector for moisture-vapor, and hydrophobic polyvinylidene fluoride fibers as the repellent components to avoid the formation of capillary water under high humidity. The desorption rate of water molecules increases from 10 to 18 mg min-1 , while the diameters of polyacrylonitrile fibers reduce from 1.02 to 0.14 µm. Significantly, by introducing the hydroxyl on the surface of polyacrylonitrile nanofibers, rapid adsorption-desorption of the water molecules is observed. Moreover, by constructing a hydrophobic to super-hydrophilic gradient structure, the MVTR increases from 10 346 to 14 066 g m-2 d-1 . Interestingly, the prepared fibrous membranes is easy to clean. More importantly, benefiting from enhanced slip effect, the resultant fibrous membranes presented a low air resistance of 86 Pa. A field test in Shanghai shows that the air filter maintains stable PM2.5 purification efficiency of 99.99% at high MVTR during haze event.

Comparison of semi-quantitative and quantitative dynamic contrast-enhanced MRI evaluations of vertebral marrow perfusion in a rat osteoporosis model.

BACKGROUND: This study aims to investigate the technical feasibility of semi-quantitative and quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the assessment of longitudinal changes of marrow perfusion in a rat osteoporosis model, using bone mineral density (BMD) measured by micro-computed tomography (micro-CT) and histopathology as the gold standards. METHODS: Fifty rats were randomly assigned to the control group (n=25) and ovariectomy (OVX) group whose bilateral ovaries were excised (n=25). Semi-quantitative and quantitative DCE-MRI, micro-CT, and histopathological examinations were performed on lumbar vertebrae at baseline and 3, 6, 9, and 12 weeks after operation. The differences between the two groups in terms of semi-quantitative DCE-MRI parameter (maximum enhancement, Emax), quantitative DCE-MRI parameters (volume transfer constant, Ktrans; interstitial volume, Ve; and efflux rate constant, Kep), micro-CT parameter (BMD), and histopathological parameter (microvessel density, MVD) were compared at each of the time points using an independent-sample t test. The differences in these parameters between baseline and other time points in each group were assessed via Bonferroni's multiple comparison test. A Pearson correlation analysis was applied to assess the relationships between DCE-MRI, micro-CT, and histopathological parameters. RESULTS: In the OVX group, the Emax values decreased significantly compared with those of the control group at weeks 6 and 9 (p=0.003 and 0.004, respectively). The Ktrans values decreased significantly compared with those of the control group from week 3 (p<0.05). However, the Ve values decreased significantly only at week 9 (p=0.032), and no difference in the Kep was found between two groups. The BMD values of the OVX group decreased significantly compared with those of the control group from week 3 (p<0.05). Transmission electron microscopy showed tighter gaps between vascular endothelial cells with swollen mitochondria in the OVX group from week 3. The MVD values of the OVX group decreased significantly compared with those of the control group only at week 12 (p=0.023). A weak positive correlation of Emax and a strong positive correlation of Ktrans with MVD were found. CONCLUSIONS: Compared with semi-quantitative DCE-MRI, the quantitative DCE-MRI parameter Ktrans is a more sensitive and accurate index for detecting early reduced perfusion in osteoporotic bone.

Aeolian process of the dried-up riverbeds of the Hexi Corridor, China: a wind tunnel experiment.

Wind tunnel studies, which remain limited, are an important tool to understand the aeolian processes of dried-up riverbeds. The particle size, chemical composition, and the mineral contents of sediments arising from the dried river beds are poorly understood. Dried-up riverbeds cover a wide area in the Hexi Corridor, China, and comprise a complex synthesis of different land surfaces, including aeolian deposits, pavement surfaces, and Takyr crust. The results of the present wind tunnel experiment suggest that aeolian transport from the dried-up riverbeds of the Hexi Corridor ranges from 0 to 177.04 g/m2/min and that dry riverbeds could be one of the main sources of dust emissions in this region. As soon as the wind velocity reaches 16 m/s and assuming that there are abundant source materials available, aeolian transport intensity increases rapidly. The dried-up riverbed sediment and the associated aeolian transported material were composed mainly of fine and medium sands. However, the transported samples were coarser than the bed samples, because of the sorting effect of the aeolian processes on the sediment. The aeolian processes also led to regional elemental migration and mineral composition variations.