Morphologische Entwicklung von mäandrierenden Flüssen bei unterschiedlichen Abflussregimes

This PhD thesis investigates the effects of changing discharge regimes on the morphological development of meandering rivers. The reduction of discharge causes bed morphology and planform changes in alluvial rivers with erodible banks, and restoring the discharge may alter the existing morphology, leading to a new (so far unpredictable) river course. The present thesis explores the capability of the open-source software Delft3D to simulate the adaption of both planform dynamics and bed topography to changed discharge regimes. A specific reach in the Dhaleshwari River (Bangladesh) is taken as a case study as it provides relevant data for model validation. Both two-dimensional (2D) and three-dimensional (3D) modelling approaches were applied. The 3D model, which was calibrated against measured 3D flow data, was used for predicting bed level changes over a one-year period. The simulated morphological changes showed a certain degree of resemblance with the available field data, but the required computational time prevented further analyses. Therefore, a 2D model, in which the parameterization of the 3D flow effect was validated against curved flume data, was used to simulate the morphological development for different discharge scenarios over a 10-year period. The results of the simulations revealed that the 2D model could predict scour depth, bank erosion, and riffle-pool sequences under both constant and varying discharge scenarios. However, the prediction of channel bankfull width showed some deficiencies. The simulations with varying discharge demonstrated a more realistic prediction of the meander planform than the simulations with constant discharge. The conclusion from this research is that a 2D modelling approach, in combination with a time-varying discharge, can be used to simulate the natural dynamics of meandering rivers, both in terms of the development of bed topography and channel planform. The results further revealed that a discharge magnitude of about 90% of the bankfull discharge represents the dominant discharge, and that the meander wavelength increases with the discharge magnitude. The results of the simulation for time-varying discharge records revealed that larger floods favor enlargement of meander wavelength and smaller floods favor shortening of meander wavelength during the first 50% of the simulation period. However, after the first 5-year period, the meander wavelength becomes nearly unresponsive to altered high- and low- floods.Diese Doktorarbeit untersucht die Auswirkungen eines sich ändernden Abflussregimes auf die morphologische Entwicklung mäandrierender Flüsse. Eine Verringerung des Abflusses führt zu Veränderungen der Flussschlauchmorphologie und der Laufform alluvialer Flüsse mit erodierbaren Bänken und die Wiederherstellung des Abflusses kann zu einem neuen (bisher unvorhersehbaren) Flussverlauf führen. Die vorliegende Arbeit beschäftigt sich mit der Frage, in wie weit die Open-Source-Software Delft3D in der Lage ist, die Anpassung sowohl der Laufformdynamik als auch der Sohlentopographie bei sich ändernden Abflussregimes zu simulieren. Als Fallstudie diente ein Flussabschnitt des Dhaleshwari Flusses in Bangladesch, für den relevante Daten für die Modellvalidierung vorlagen. Zur Modellierung wurden sowohl zweidimensionale (2D) als auch dreidimensionale (3D) Ansätze herangezogen. Das mittels gemessener 3D-Strömungsdaten kalibrierte 3D-Modell wurde zur Vorhersage der Änderungen des Sohlniveaus über einen Zeitraum von 1 Jahr herangezogen. Die Ergebnisse der Simulationen zeigten eine gewisse Ähnlichkeit der morphologischen Veränderungen mit den Felddaten, aber die erforderliche Rechenzeit verhinderte weitere Analysen. Daher wurde das 2D-Modell verwendet, für das die Parametrisierung des 3D-Strömungseffekts anhand von Laboruntersuchungen validiert wurde. Mit diesem Modell wurden verschiedene Abflussszenarien über einen Zeitraum von 10 Jahren simuliert. Kolktiefe, Ufererosion und Riffle-Pool-Sequenzen konnten mit dem 2D-Modell modelliert werden, wobei sich jedoch Abweichungen bei der bordvollen Breite ergaben. Die Simulationen mit variierendem Abfluss zeigten eine realistischere Vorhersage der Laufform als die Simulationen mit konstantem Abfluss. Diese Ergebnisse verdeutlichen, dass ein 2D-Modellierungsansatz in Kombination mit einer Ganglinie verwendet werden kann, um die natürliche Dynamik der Sohlentopographie und Laufform von mäandrierenden Flüssen zu simulieren. Die Ergebnisse zeigten ferner, dass ein Abfluss von etwa 90% des bordvollen Abflusses den bettformenden Abfluss darstellt und dass die Mäanderwellenlänge mit dem Abfluss zunimmt. Die Ergebnisse der Simulation mit Ganglinien zeigten, dass größere Hochwasserereignisse eine Vergrößerung und kleinere eine Verkürzung der Mäanderwellenlänge während der ersten 50% der Simulationsperiode begünstigen. Nach den ersten 5 Jahren reagiert die Mäanderwellenlänge jedoch kaum mehr auf veränderte Hoch- und Niedrigwasser

Effect of size and location of solid on conjugate heat transfer in porous cavity

The highlight of this article is the influence of a solid over heat transfer characteristics in a square porous cavity. The solid placed inside the porous medium is fraction of the whole domain whose size is varied at 5 different locations of the cavity such as left ( = 0 ), center ( = 0.5), right ( = 1), mid of left and center ( = 0.25), mid of center and right ( = 0.75) wall of cavity. The equations that govern the physical phenomenon have been simplified using popular numerical technique such as finite element method. These simultaneous equations are solved for the solution variables such as temperature and the stream function. The physical domain is divided into smaller segments with the help of triangular elements. The left and right vertical surfaces of cavity are maintained at hot and cold temperature Th and Tc such that Th>Tc

Alteration of metabolic biomarkers and oxidative stress indices in pashmina (Changthangi) goats under climate change

The main aim of this study was to evaluate climate change induced variation of metabolic biomarkers and oxidative stress indices in different age groups of pashmina goats. Adult animals in comparison to young and old animals had significantly higher levels of glucose, glycated haemoglobin (GHb), fructosamine and total protein during summer and significantly higher levels of glucose, fructosamine and haemoglobin (Hb) during winter. Significantly reduced levels of these biochemicals were noted in winter than summer in all age groups except for glucose in young and old, GHb in young and Hb in adult animals. Urea and acetoacetate levels were significantly higher in young animals than adults during winter. Higher betahydroxybutyrate and lower propionate levels were noted during winter than summer in all age groups. Significantly higher levels of insulin, T3, T4 and lower levels of TSH and cortisol in adult animals were noted in both seasons. Significant rise of insulin in adult, T3 and T4 in young and old, cortisol in young and TSH in all animals occurred during winter. Level of GSH in summer, CAT and SOD in winter were significantly higher in adult animals whereas, that of LPO were in young animals. Decrease in levels of antioxidants and increase of oxidants during winter was significant in all age groups. Hence, young and old age groups of pashmina goats are more vulnerable to metabolic alterations under climatic stress than the adult group

Enhanced drug delivery and wound healing potential of berberine-loaded chitosan–alginate nanocomposite gel: characterization and in vivo assessment

Berberine–encapsulated polyelectrolyte nanocomposite (BR–PolyET–NC) gel was developed as a long-acting improved wound healing therapy. BR–PolyET–NC was developed using an ionic gelation/complexation method and thereafter loaded into Carbopol gel. Formulation was optimized using Design-Expert® software implementing a three-level, three-factor Box Behnken design (BBD). The concentrations of polymers, namely, chitosan and alginate, and calcium chloride were investigated based on particle size and %EE. Moreover, formulation characterized in vitro for biopharmaceutical performances and their wound healing potency was evaluated in vivo in adult BALB/c mice. The particle distribution analysis showed a nanocomposite size of 71 ± 3.5 nm, polydispersity index (PDI) of 0.45, ζ–potential of +22 mV, BR entrapment of 91 ± 1.6%, and loading efficiency of 12.5 ± 0.91%. Percentage drug release was recorded as 89.50 ± 6.9% with pH 6.8, thereby simulating the wound microenvironment. The in vitro investigation of the nanocomposite gel revealed uniform consistency, well spreadability, and extrudability, which are ideal for topical wound use. The analytical estimation executed using FT-IR, DSC, and X-ray diffraction (XRD) indicated successful formulation with no drug excipients and without the amorphous state. The colony count of microbes was greatly reduced in the BR–PolyET–NC treated group on the 15th day from up to 6 CFU compared to 20 CFU observed in the BR gel treated group. The numbers of monocytes and lymphocytes counts were significantly reduced following healing progression, which reached to a peak level and vanished on the 15th day. The observed experimental characterization and in vivo study indicated the effectiveness of the developed BR–PolyET–NC gel toward wound closure and healing process, and it was found that >99% of the wound closed by 15th day, stimulated via various anti-inflammatory and angiogenic factors

Crosstalk between Chemokine Receptor CXCR4 and Cannabinoid Receptor CB2 in Modulating Breast Cancer Growth and Invasion

Cannabinoids bind to cannabinoid receptors CB(1) and CB(2) and have been reported to possess anti-tumorigenic activity in various cancers. However, the mechanisms through which cannabinoids modulate tumor growth are not well known. In this study, we report that a synthetic non-psychoactive cannabinoid that specifically binds to cannabinoid receptor CB(2) may modulate breast tumor growth and metastasis by inhibiting signaling of the chemokine receptor CXCR4 and its ligand CXCL12. This signaling pathway has been shown to play an important role in regulating breast cancer progression and metastasis.We observed high expression of both CB(2) and CXCR4 receptors in breast cancer patient tissues by immunohistochemical analysis. We further found that CB(2)-specific agonist JWH-015 inhibits the CXCL12-induced chemotaxis and wound healing of MCF7 overexpressing CXCR4 (MCF7/CXCR4), highly metastatic clone of MDA-MB-231 (SCP2) and NT 2.5 cells (derived from MMTV-neu) by using chemotactic and wound healing assays. Elucidation of the molecular mechanisms using various biochemical techniques and confocal microscopy revealed that JWH-015 treatment inhibited CXCL12-induced P44/P42 ERK activation, cytoskeletal focal adhesion and stress fiber formation, which play a critical role in breast cancer invasion and metastasis. In addition, we have shown that JWH-015 significantly inhibits orthotopic tumor growth in syngenic mice in vivo using NT 2.5 cells. Furthermore, our studies have revealed that JWH-015 significantly inhibits phosphorylation of CXCR4 and its downstream signaling in vivo in orthotopic and spontaneous breast cancer MMTV-PyMT mouse model systems.This study provides novel insights into the crosstalk between CB(2) and CXCR4/CXCL12-signaling pathways in the modulation of breast tumor growth and metastasis. Furthermore, these studies indicate that CB(2) receptors could be used for developing innovative therapeutic strategies against breast cancer

Approximation solution for system of generalized ordered variational inclusions with ⊕ operator in ordered Banach space

Abstract The resolvent operator approach is applied to address a system of generalized ordered variational inclusions with ⊕ operator in real ordered Banach space. With the help of the resolvent operator technique, Li et al. (J. Inequal. Appl. 2013:514, 2013; Fixed Point Theory Appl. 2014:122, 2014; Fixed Point Theory Appl. 2014:146, 2014; Appl. Math. Lett. 25:1384-1388, 2012; Fixed Point Theory Appl. 2013:241, 2013; Eur. J. Oper. Res. 16(1):1-8, 2011; Fixed Point Theory Appl. 2014:79, 2014; Nonlinear Anal. Forum 13(2):205-214, 2008; Nonlinear Anal. Forum 14: 89-97, 2009) derived an iterative algorithm for approximating a solution of the considered system. Here, we prove an existence result for the solution of the system of generalized ordered variational inclusions and deal with a convergence scheme for the algorithms under some appropriate conditions. Some special cases are also discussed

2D numerical simulation of meander morphology

This paper describes the application of the two-dimensional (2D) modelling approach implemented in the open-source code Delft3D for the simulation of morphological development of a natural meandering river. A specific reach of the Dhaleshwari River (Bangladesh) for which field data has been available served as case study. The bed morphology and meander planform adjustment in the study area were simulated over a 10-year period considering a time-varying discharge scenario. The results showed that the 2D model was able to reproduce morphological characteristics such as scour depth, bank erosion and pool-riffle morphology, even though the model showed some deficiencies to reproduce bankfull channel width and transverse bed slopes. Regarding the planimetric evolution, the planform parameters (i.e., meander belt width, meander wavelength and radius of curvature) confirmed that the model results are realistic and are in agreement with results reported in the literature

New generalized systems of nonlinear ordered variational inclusions involving ⊕ operator in real ordered Hilbert spaces

Abstract This manuscript deals with two general systems of nonlinear ordered variational inclusion problems. We also construct some new iterative algorithms for finding approximation solutions to the general systems of nonlinear ordered variational inclusions and prove the convergence of the sequences obtained by the schemes. The results presented in the manuscript are new and improve some well-known results in the literature

A Comprehensive Scientific Claims on Ethnobotany, Phytochemical Pharmacological and Toxicology of Withania somnifera (L.) Dunal

For more than 3,000 years, Withania somnifera, commonly known as Ashwagandha, has been utilised in traditional and Ayurvedic medicine. It belongs to the ginger family. Dry powder, crude extract, and refined metabolites of the plant have all demonstrated potential therapeutic advantages in animal trials because it is a medicinal plant. Withanolides are the primary metabolites of the plant, and they are responsible for the therapeutic effects of the herb. Despite the fact that other review papers on this plant have previously been published, this review article is being provided in order to gather all of based on the most recent data on its pharmacological and phytochemical effects, which have been investigated using a variety of approaches. According to research, Ashwagandha has anti-inflammatory, adaptogen, anti-parkinsonian, anti-oxidant, and memory-boosting properties, and anticancer effects in addition to other benefits. Other effects, such as immunomodulation, hypolipidemia, antimicrobial activity, Investigations have also been done on cardiovascular defence, sexual behaviour, tolerance, and reliance. These outcomes are extremely encouraging, and they recommend more research into this herb to confirm these results and find further potential medicinal characteristics. Clinical studies including the use of ashwagandha for a number of illnesses should be carried out as well. The new evidence on its pharmacological and phytochemical activities is described in the current publication. In order to give thorough information on the ethnobotany, traditional applications, phytochemistry, and pharmacological efficacy of the medicinal plant, W. somnifera, from reliable sources, the present review has primary objectives. Keywords:  Withania somnifera, Solanaceae, traditional claim, ethnobotany, phytochemistry, phytopharmacolog