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The surfactant properties of perfluorooctanesulfonic acid (PFOS) impact its environmental behavior, especially under high-ionic strength conditions. We observed an apparent PFOS concentration decre...

Dobutamine stress echocardiography is a safe diagnostic test with low incidence of serious complications. Atropine has been shown to reduce test duration without increasing the rate of complications. We present a case of a 52-year-old man with end stage renal disease who experienced syncope due to ventricular asystole after atropine administration during a dobutamine stress test. The underlying pathophysiology is discussed. J Med Cases. 2020;11(5):125-128 doi: https://doi.org/10.14740/jmc3465

Accumulation of NaCl in soil causes osmotic stress in plants, and sodium (Na+ ) and chloride (Cl- ) cause ion toxicity, but also reduce the potassium (K+ ) uptake by plant roots and stimulate the K+ efflux through the cell membrane. Thus, decreased K+ /Na+ ratio in plant tissue lead us to hypothesise that elevated levels of K+ in nutrient medium enhance this ratio in plant tissue and cytosol to improve enzyme activation, osmoregulation and charge balance. In this study, wheat was cultivated at different concentrations of K+ (2.2, 4.4 or 8.8 mm) with or without salinity (1, 60 or 120 mm NaCl) and the effects on growth, root and shoot Na+ and K+ distribution and grain yield were determined. Also, the cytosolic Na+ concentration was investigated, as well as photosynthesis rate and water potential. Salinity reduced fresh weight of both shoots and roots and dry weight of roots. The grain yield was significantly reduced under Na+ stress and improved with elevated K+ fertilisation. Elevated K+ level during cultivation prevented the accumulation of Na+ into the cytosol of both shoot and root protoplasts. Wheat growth at vegetative stage was transiently reduced at the highest K+ concentration, perhaps due to plants' efforts to overcome a high solute concentration in the plant tissue, nevertheless grain yield was increased at both K+ levels. In conclusion, a moderately elevated K+ application to wheat seedlings reduces tissue as well as cytosolic Na+ concentration and enhances wheat growth and grain yield by mitigating the deleterious effects of Na+ toxicity.

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Item does not contain fulltext OBJECTIVE: Palliative pelvic exenteration (PPE) is a technically complex operation with high morbidity and mortality rates, considered in patients with limited life expectancy. There is little evidence to guide practice. We performed a systematic review to evaluate the impact of PPE on symptom relief and quality of life (QoL). METHODS: A systematic review was conducted according to the PRISMA guidelines using Ovid MEDLINE, EMBASe, and PubMed databases for studies reporting on outcomes of PPE for symptom relief or QoL. Descriptive statistics were used on pooled patient cohorts. RESULTS: Twenty-three historical cohorts and case series were included, comprising 509 patients. No comparative studies were found. Most malignancies were of colorectal, gynaecological and urological origin. Common indications for PPE were pain, symptomatic fistula, bleeding, malodour, obstruction and pelvic sepsis. The pooled median postoperative morbidity rate was 53.6% (13-100%), the median in-hospital mortality was 6.3% (0-66.7%), and median OS was 14 months (4-40 months). Some symptom relief was reported in a median of 79% (50-100%) of the patients, although the magnitude of effect was poorly measured. Data for QoL measures were inconclusive. Five studies discouraged performing PPE in any patient, while 18 studies concluded that the procedure can be considered in highly selected patients. CONCLUSION: Available evidence on PPE is of low-quality. Morbidity and mortality rates are high with a short median OS interval. While some symptom relief may be afforded by this procedure, evidence for improvement in QoL is limited. A highly selective individualised approach is required to optimise the risk:benefit equation.

Accumulation of NaCl in soil causes osmotic stress in plants, and sodium (Na

The asymmetric synthesis of dragmacidin D (1) was completed in 10 steps. Its sole stereocenter was set by using direct asymmetric alkylation enabled by a C2-symmetric tetramine and lithium N-(trimethylsilyl)-tert-butylamide as the enolization reagent. A central Larock indole synthesis was employed in a convergent assembly of the heterocyclic subunits. The stereochemical evidence from this work strongly supports the predicted S configuration at the 6′′′ position, which is consistent with other members of the dragmacidin family of natural products.

Pelvic exenteration (PE) is the preferred treatment available for selected patients diagnosed with locally advanced or recurrent cancer confined to the pelvis. Currently, the majority of the literature reports only on short-term survival and quality-of-life (QoL) outcomes. The aim of this prospective cohort study was to describe long-term survival and QoL outcomes following PE.This was a cohort study of consecutive patients undergoing PE from 1994 to 2016 at a major teaching hospital in Sydney, Australia. From 2008, consenting patients were also included in a prospective QoL study. Main outcomes were long-term survival and QoL assessed with SF-36Some 515 patients underwent PE for locally advanced or recurrent cancer. The cumulative 5- and 10-year overall survival rates were 48·6 and 37·8 per cent respectively. The survival estimates were significantly higher for patients with advanced primary rectal cancer (P = 0·045) and those in whom a clear resection margin was achieved (P0·001). Some 287 patients were enrolled into the QoL study. Response rates at baseline, 6 months and 5 years were 92·0, 70·0 and 33 per cent respectively. Patients had recovered to their preoperative QoL status by 6 months and, among survivors, QoL remained essentially unchanged during the 5-year follow-up.Patients who underwent PE owing to advanced primary rectal cancer or achieved a clear resection margin had a greater chance of survival. Overall, QoL returned to baseline within 6 months after surgery.

Vulvodynia affects a maximum of 14 million U.S. women; however, it has not been adequately characterized. Traditional Chinese Medicine (TCM) offers pattern diagnoses that may be considered vulvodynia phenotypes and may guide the development of more targeted treatments.In women with vulvodynia, to explore relationships between the TCM patterns and pain.In an exploratory study, 36 women diagnosed with vulvodynia had a TCM assessment and completed the Short Form McGill Pain Questionnaire (SF-MPQ).All 36 women were diagnosed with one of the two TCM patterns (excess heat [n = 28] or excess cold [n = 8]). Although not statistically significant, (1) the excess heat pattern group had a higher mean sensory score (14.4 ± 6.0) and mean affective pain score (4.1 ± 2.8) (more pain) compared with the mean sensory score (13.3 ± 5.9) and mean affective score (3.3 ± 1.8) of the excess cold pattern group; (2) there was a higher mean score for neuropathic sensory descriptors in the excess heat pattern group (1.55 ± .58) compared with the excess cold pattern group (1.16 ± 0.72); and (3) there was a higher mean score for nociceptive sensory descriptors in the excess cold pattern group (1.23 ± 0.45) compared with the excess heat pattern group (1.14 ± 0.62). The difference in the hot-burning mean score between the two TCM pattern groups was statistically significant (t [34] = 6.55, p 0.0001).Intriguing trends were observed in the pain scores for the two TCM pattern groups. The possibility that TCM pattern groups have different types of pain (neuropathic vs. nociceptive) deserves further research in larger samples. If these exploratory findings are confirmed, the characterization of TCM patterns could lead to new treatments for vulvodynia.

Background The current paradigm of intracellular redox chemistry maintains that cells establish a reducing environment maintained by a pool of small molecule and protein thiol to protect against oxidative damage. This strategy is conserved in mesophilic organisms from all domains of life, but has been confounded in thermophilic organisms where evidence suggests that intracellular proteins have abundant disulfides. Methods Chemical labeling and 2-dimensional gel electrophoresis were used to capture disulfide bonding in the proteome of the model thermophile Sulfolobus solfataricus. The redox poise of the metabolome was characterized using both chemical labeling and untargeted liquid chromatography mass spectrometry. Gene annotation was undertaken using support vector machine based pattern recognition. Results Proteomic analysis indicated the intracellular protein thiol of S. solfataricus was primarily in the disulfide form. Metabolic characterization revealed a lack of reduced small molecule thiol. Glutathione was found primarily in the oxidized state (GSSG), at relatively low concentration. Combined with genetic analysis, this evidence shows that pathways for synthesis of glutathione do exist in the archaeal domain. Conclusions In observed thermophilic organisms, thiol abundance and redox poise suggest that this system is not directly utilized for protection against oxidative damage. Instead, a more oxidized intracellular environment promotes disulfide bonding, a critical adaptation for protein thermostability. General significance Based on the placement of thermophilic archaea close to the last universal common ancestor in rRNA phylogenies, we hypothesize that thiol-based redox systems are derived from metabolic pathways originally tasked with promoting protein stability.

The mechanism of the tert-butylhydroperoxide-mediated, Pd(Quinox)-catalyzed Wacker-type oxidation was investigated to evaluate the hypothesis that a selective catalyst-controlled oxidation could be achieved by rendering the palladium coordinatively saturated using a bidentate amine ligand. The unique role of the Quinox ligand framework was probed via systematic ligand modifications. The modified ligands were evaluated through quantitative Hammett analysis, which supports a "push-pull" relationship between the electronically asymmetric quinoline and oxazoline ligand modules.

Triphenylphosphinegold(I) complexes catalyze the Claisen-type rearrangement of aryl allyl ethers to the corresponding branched and linear products. The product distribution depends on the olefin geometry of the allylic ether. Stereochemical transfer experiments support an ionic mechanism.

The asymmetric synthesis of dragmacidin D (1) was completed in 10 steps. Its sole stereocenter was set by using direct asymmetric alkylation enabled by a C2-symmetric tetramine and lithium N-(trimethylsilyl)-tert-butylamide as the enolization reagent. A central Larock indole synthesis was employed in a convergent assembly of the heterocyclic subunits. The stereochemical evidence from this work strongly supports the predicted S configuration at the 6′′′ position, which is consistent with other members of the dragmacidin family of natural products.

Objective: This post-marketing surveillance study aimed to investigate the contraceptive efficacy and tolerability of a combination tablet containing chlormadinone acetate 2mg and ethinylestradiol 0.03mg (Belara®) in daily gynaecological practice. A secondary aim was investigation of the changes in clinical signs of androgenisation. Design: 21 820 female patients were surveyed during a six-cycle period by 3600 gynaecologists throughout Germany. Results: Out of 21 820 patients, a total of 19 650 women (90.1%) completed the study. Chlormadinone acetate 2mg/ethinylestradiol 0.03mg had excellent contraceptive efficacy with an adjusted Pearl index of 0.076 (unadjusted Pearl index: 0.344), calculated from 125 634 cycles of exposure. Cycle control was good, with beneficial reductions in intracyclic bleeding (22.9% in cycle 1, 1.6% in cycle 6), amenorrhoea, severe withdrawal bleeding and dysmenorrhoea. At cycle six, only 1.2, 0.4 and 0.5% of all patients complained about spotting, breakthrough bleeding and amenorrhoea, respectively. At baseline, 69.9% of the women showed androgen-related skin disorders. After six cycles of chlormadinone acetate 2mg/ ethinylestradiol 0.03mg, these disorders were improved in 86.5% of patients, including 28.5% who had complete resolution. Correspondingly, greasy or very greasy hair condition decreased from 47.0 to 13.6%. Chlormadinone acetate 2mg/ethinylestradiol 0.03mg was well tolerated; a total of two venous thromboembolic events (VTEs) occurred, and both patients recovered with appropriate treatment. Breast pain (3.6%) and migraine/headache (2.6%) were the most frequently reported adverse events. Conversely, these symptoms disappeared in most women (84.5 and 79.9%) who experienced them prior to chlormadinone acetate 2mg/ethinylestradiol 0.03mg treatment. Conclusions: These results support the reliable contraceptive efficacy, cycle stability and tolerability reported in previous clinical trials and confirm the marked antiandrogenic properties of chlormadinone acetate 2mg/ethinylestradiol 0.03mg.

Terminal alkene substrates can be converted to methyl ketone products via a palladium-catalyzed process known as the Wacker oxidation. This process has found widespread application in targeted synthesis, since alkene substrates are easily accessed and unreactive under diverse reaction conditions substrates and the resultant carbonyl products are common precursors for diverse synthetic manipulations. This chapter covers the application of the Wacker oxidation and variations of the Wacker oxidation to various types of alkene substrates. The literature covered spans the inception of the reaction in 1959 through November 2012. A discussion of the current mechanistic understanding is presented, emphasizing considerations that are relevant to synthetic application, including how the nature of the alkene substrate and nucleophiles other than water are proposed to influence the mechanistic pathways and ultimately the product distribution. The “Scope and Limitations” section is separated into discussions relating to functional group tolerance, the influence of heteroatoms proximal to the alkene substrate, and Wacker-type oxidations that do not result in carbonyl products, such as cyclization reactions and aza-Wacker reactions. Select applications of the Wacker oxidation in total synthesis are presented, as well as a comparison to other methods and examples of experimental conditions. Keywords: Wacker oxidation(s); palladium-catalyzed; nucleopalladation; oxypalladation; alkene(s); olefin(s); ketone(s); Markovnikov addition; anti-Markovnikov addition; ligand-modulation; molecular oxygen; tert-butylhydroperoxide; Benzoquinone; allylic alcohol(s); homoallylic alchol(s); allylic amine(s); homoallylic amine(s); Wacker cyclization; acetal(s); aza-Wacker

This study combines enthalpy probe measurements in a direct current (DC) plasma jet under atmospheric conditions and the characterization of sprayed coatings. Two different nozzle diameters were used as anode profiles. A detailed description of the experimental setup is given together with preliminary results. These results emphasize the usability of enthalpy probe measurements in thermal plasma jets for obtaining temperature distributions. For zirconia, the deposition efficiency, density, and structure of the coatings formed with the different anode profiles were compared.

Much research has been performed in the field of thermal barrier coatings (TBCs) deposited by atmospheric plasma spraying of ZrO2-Y2O3. The necessity of efficient thermal insulation, corrosion resistance, and sufficient lifetime under thermomechanical loads promotes the development of TBCs of several millimeters in thickness. However, some problems arise with the production of thick TBCs, such as poor adhesion and low thermal shock resistance. These problems are not observed clearly when the TBCs are, for example, 300 µm thick. This article presents strategies of thick TBC lifetime optimization by different cooling systems. Attempts have been made to improve thermal shock resistance (TSR) by applying thicker coatings with graded porosity, but they failed. Besides metallographical evaluation and scanning electron microscopy (SEM) analysis, microcracks and porosity were determined. Furthermore, the results of bond strength and burner rig tests are presented, and forthcoming experimental tasks are outlined.

Thermal spray processes such as plasma spraying and HVOF have gained markets due to a steady process of development of materials and equipment. One disadvantage of thermal spray processes is that costs must be competitive compared to techniques such as PTA and electroplating. In order to reduce costs, the more economical spray processes like conventional wire flame spraying, as well as arc spraying, are becoming more popular. There are modern arc spray gun designs on the market that meet the requirements of modern coating properties, for example aviation overhaul applications as well as the processing of cored wires. Nevertheless, the physical basis of arc spraying is well known. The aim of the present investigation is to show how the influence of spray velocity (not particle velocity) affects coating structure with respect to arc spray parameters.

A well operating corrosion protection essentially prevents corrosive attacks on components and prolongs their endurance. A review of characteristic kinds of corrosion observed on coated components is given and the mechanisms of damage are systematically discussed. Methods of testing are introduced, that allow predictions of sensitivity to the respective types of corrosion.

Tarnish layers are formed in the heat affected zone during the welding of steels and nickel based alloys. They commonly consist of oxides of the alloying elements. The corrosion behaviour of welded components is generally influenced by the thickness and composition of the oxide films. In the following the corrosion behaviour of annealed samples cut from NiMo28 and NiMo16Cr16Ti is investigated, correlating XPS, SNMS and SEM/EDX data to their pitting corrosion potentials.

New results on the carbide formation in aluminium-carbon fibre composites are reviewed, with their implications for technology, including vacuum infiltration of carbon-fibre preforms with liquid aluminium. The microstructure of infiltrated specimens was studied with the aid of transmission electron microscopy. Most lath-like carbide crystals investigated in this work are twins. Twinning is probably connected with the squeezing stresses during matrix cooling due to a high difference in thermal expansion coefficients of carbide and metal. The analytical description of experimental data in the light of the crystal-growth concept allows us to conclude that carbides grow during infiltration, predominantly at the time of fibre contact with molten aluminium, but not during matrix solidification and its subsequent cooling. The growth rate of carbide crystals is limited rather by the interface kinetics than by carbon diffusion in the melt as was assumed previously. This allows some effective methods of process control to be found, for example, growth step retardation by means of an adsorption-active impurity.

Magnetic resonance imaging (MRI) has the potential to identify pathology responsible for low back pain (LBP). However, the importance of findings on MRI remains controversial. We aimed to systematically review whether MRI findings of the lumbar spine predict future LBP in different samples with and without LBP.MEDLINE, CINAHL and EMBASE databases were searched. Included were prospective cohort studies investigating the relationship between baseline MRI abnormalities of the lumbar spine and clinically important LBP outcome at follow-up. We excluded cohorts with specific diseases as the cause of their LBP. Associations between MRI findings and LBP pain outcomes were extracted from eligible studies.A total of 12 studies met the inclusion criteria. Six studies presented data on participants with current LBP; one included a sample with no current LBP, three included a sample with no history of LBP and two included mixed samples. Due to small sample size, poor overall quality and the heterogeneity between studies in terms of participants, MRI findings and clinical outcomes investigated, it was not possible to pool findings. No consistent associations between MRI findings and outcomes were identified. Single studies reported significant associations for Modic changes type 1 with pain, disc degeneration with disability in samples with current LBP and disc herniation with pain in a mixed sample.The limited number, heterogeneity and overall quality of the studies do not permit definite conclusions on the association of MRI findings of the lumbar spine with future LBP (PROSPERO: CRD42012002342).

The reaction is a useful complement to the traditional Tsuji—Wacker oxidation of internal alkenes.

The association of stem cells (SCs) with biomaterials promises to be the protagonist for future regenerative medicine in the treatment of tissue and organ lesions. Stem cells were cultivated in scaffolds constructed by the electrospinning technique, using poly-D,L-lactic acid (PDLLA) associated or not with Spirulina biomass (PDLLA/Sp), which has bioactive components of interest for tissue engineering (TE). Physicochemical analyses were performed, such as morphology, fiber diameter, degradability, residual solvent, roughness, contact angle with water, among others. SCs adhesion, proliferation and scaffold cytotoxicity were also evaluated. Nanofibers without beads and with characteristics similar to the natural extracellular matrix (ECM) in terms of mechanical and topographical properties were obtained. In biological tests it was found that SCs adhered more and had greater viability in the PDLLA/Sp molds, when compared with the PDLLA scaffolds. The scaffolds were shown to be atoxic for the SCs. It can be concluded that the scaffolds developed in this work have the characteristics to be a new biomaterial suitable for use in TE.

The Pd-catalyzed TBHP-mediated Wacker-type oxidation of internal alkenes is reported. The reaction uses 2-(4,5-dihydro-2-oxazolyl)quinoline (Quinox) as ligand and TBHP(aq) as oxidant to deliver single ketone constitutional isomer products in a predictable fashion from electronically biased olefins. This methodology is showcased through its application on an advanced intermediate in the total synthesis of the antimalarial drug artemisinin.

Vacuum-plasma-sprayed titanium-manganese alloy electrode layers are intended to improve the economy and efficiency of the synthesis of electrolytic manganese dioxide, which is commercially used as cathodic material in primary batteries. Titanium anodes with a high content of manganese offer high electrochemical activity and corrosion resistance, but poor mechanical stability. Therefore, dense and well-bonded coatings of this brittle alloy were vacuum plasma sprayed onto ductile substrates using commercially pure titanium and manganese powder mixtures as well as mechanically alloyed powders. The mechanically alloyed powders, fabricated in a planetary ball mill, are suitable for the plasma spray process. The microstructure and electrochemical properties of the anode coatings produced by these two methods are discussed. Results are compared to commercially pure titanium anodes.

Where there is life, there are viruses. The impact of viruses on evolution, global nutrient cycling, and disease has driven research on their cellular and molecular biology. Knowledge exists for a wide range of viruses; however, a major exception are viruses with archaeal hosts. Archaeal virus-host systems are of great interest because they have similarities to both eukaryotic and bacterial systems and often live in extreme environments. Here we report the first proteomics-based experiments on archaeal host response to viral infection. Sulfolobus Turreted Icosahedral Virus (STIV) infection of Sulfolobus solfataricus P2 was studied using 1D and 2D differential gel electrophoresis (DIGE) to measure abundance and redox changes. Cysteine reactivity was measured using novel fluorescent zwitterionic chemical probes that, together with abundance changes, suggest that virus and host are both vying for control of redox status in the cells. Proteins from nearly 50% of the predicted viral open reading frames were found along with a new STIV protein with a homologue in STIV2. This study provides insight to features of viral replication novel to the archaea, makes strong connections to well-described mechanisms used by eukaryotic viruses such as ESCRT-III mediated transport, and emphasizes the complementary nature of different omics approaches.

The origin and evolutionary relationship of viruses is poorly understood. This makes archaeal virus-host systems of particular interest because the hosts generally root near the base of phylogenetic trees, while some of the viruses have clear structural similarities to those that infect prokaryotic and eukaryotic cells. Despite the advantageous position for use in evolutionary studies, little is known about archaeal viruses or how they interact with their hosts, compared to viruses of bacteria and eukaryotes. In addition, many archaeal viruses have been isolated from extreme environments and present a unique opportunity for elucidating factors that are important for existence at the extremes. In this article we focus on virus-host interactions using a proteomics approach to study Sulfolobus Turreted Icosahedral Virus (STIV) infection of Sulfolobus solfataricus P2. Using cultures grown from the ATCC cell stock, a single cycle of STIV infection was sampled six times over a 72 h period. More than 700 proteins were identified throughout the course of the experiments. Seventy one host proteins were found to change their concentration by nearly twofold (p

Electric arc spraying has been successfully used for many industrial applications for more than 30 years. High-velocity oxygen fuel (HVOF) spraying is another well-established technology. Coatings produced by the HVOF process, especially carbide-containing coatings, exhibit excellent quality in terms of density and hardness. One approach to obtaining both high deposition rates and dense coatings is to combine electric arc spraying and HVOF spraying in a technique known as the “Sonarc” process. This process al-lows many feed combinations through the simultaneous use of wire and powder. This paper presents the development of a prototype. Examples of composite materials and structures, their properties, and potential applications are given.

Reactive materials such as titanium and tantalum are not suitable for the manufacture of pure and corrosion-resistant layers by atmospheric spraying processes, and thus are normally processed by vacuum plasma spraying. However, because of the large specific area of the feedstock, large amounts of previously adsorbed oxygen and nitrogen are included in the coating, often resulting in unsatisfactory corrosion behavior. This can be avoided by vacuum arc spraying using a single wire. The spraying material is a cathodic poled wire that is led without contact through a nonconsumable, water-cooled nozzle. The wire is melted by a high-frequency arc that burns between the wire and the nozzle. The process gas (argon) at-omizes the wire and accelerates the particles onto the component being coated. The process parameters strongly influence the stability of the process and the resulting microstructure of the deposit.

This volume contains the proceedings of the proceedings of the fourth TACONET conference on Self-Regulated Learning (SRL) in Technology Enhanced Learning Environments (TELEs), that took place at the Universitat de Barcelona in Spain. The TACONET conferences aim to increase awareness of SRL in TELEs among members of industry, academia and communities of practice. They also intend to stimulate research in the field of SRL in TELEs. This conference was organized by TACONET and by the STELLAR Theme Team "Selfregulated learning in technology enhanced learning environments". There was a wide variety of contributions to this conference. They can be assigned to three slightly different perspectives. While they all dealt with the topic of self-regulated learning in technology enhanced learning environments, the first group of contributions was focussed on teachers and students, the second group focussed more on learning in class while the third group dealt with learning beyond school. The variety of the topics, results and conclusions of the contributions support the hypothesis that there still is need for more research on the topic of self-regulated and technology enhanced learning.

Eigenspannungen in Metall-Keramik-Verbunden fuhren haufig zu deren vorzeitigem Versagen. Im vorliegenden Beitrag werden Ergebnisse aus Grundlagenuntersuchungen vorgestellt, bei denen der Einflus wesentlicher Werkstoffkennwerte untersucht sowie ein Vergleich der Rechenergebnisse mit Laboruntersuchungen vorgenommen wurde. Fundamental Investigations of Residual Stresses in Metal-Ceramic-Joints by FEM The reduction of damages in metal-ceramic-joints caused by residual stresses is of essential significance. Therefore, a model was created to simulate the behaviour of metal-ceramic-joints under thermal stress. In this paper, results of fundamental investigations are presented.

This study was carried out to determine the effects of cultivation period of sugarcane on some quality parameters of a vertisols. Samples were collected from the 0-30 and 30-60 cm depths of fields (subjected to burning during harvest of cane) cultivated for 29, 25 and 10 years and also from an adjacent fallow area. The samples were analyzed for pH, electrical conductivity (ECe), saturation percentage (SP), bulk density (BD), organic carbon (OC), total N (TN), particle size distribution, dry aggregate stability (DAS), soil organic matter (SOM) associated with sand size fractions (POM) and mineral N (NH4 +-N and NO3 - -N) accumulation during decomposition of soil organic matter. Results showed that cultivation or cultivation period significantly decreased SP, OC, DAS, clay content and amount of soil organic matter size fractions, while cultivation period showed no significant effect on either amount, or content of C and N of these fractions. During early weeks of mineralization of SOM, mineral N was significantly lower due to cultivation as such or in fields subjected to extended periods of cultivation. It is quite evident that the quality of heavy clay soils (e.g. vertisols) would be recovered more easily if the crop residues during harvest of the cane are incorporated into the soil. This is possibly due to the greater physical protection (due to high clay content) of organic matter against break down, thereby, improving their chances of sequestration. It is also concluded that long-term cultivation enhanced removal of fine clay particles, which might results in the long-term creation of a hard pan. Keywords: Sugarcane, vertisols, soil quality, semi-arid tropics, Sudan

Die mechanischen und technologischen Eigenschaften der durch thermisches Spritzen hergestellten metallischen Verbundwerkstoffe mit kontinuierlichen, unidirektionalen Fasern werden vorgestellt. Mit Hilfe einfacher Modelle der Kontinuumstheorie werden die theoretisch erreichbaren Werte der mechanischen Eigenschaften, unter einachsiger Zugbelastung in Faserrichtung [1], abgeschatzt. Die experimentell erhaltenen Ergebnisse werden mit den theoretisch ermittelten verglichen. Es folgt eine Analyse der moglichen Abweichungsursachen zwischen den einzelnen Ergebnissen, wobei die herstellungs- und prufungsbezogenen Aspekte im Mittelpunkt des Interesses stehen. Die Relation Theorie-Experiment dient weiterhin als Basis fur die Untersuchung der Optimierungsmoglichkeiten der mechanischen Eigenschaften betrachteter Faserverbundwerkstoffe. Es ergeben sich Richtungen fur weitere Forschungsarbeiten, die eine bessere Spezifizierung der vorhandenen Modelle sowie auch der Verbesserung der mechanischen Eigenschaften der durch thermisches Spritzen hergestellten Faserverbundwerkstoffe ermoglichen sollen. Die Untersuchungen beziehen sich auf thermisch gespritzte, stahlfaserverstarkte NiCr-Legierungen; die hier als Beispiel durchgefuhrte Analyse betrifft das Verbundwerkstoffsystem NiCr19Al6Si/25%-X12CrNi177-Faser (1.4310). Mechanical properties of unidirectional fibre-reinforced composites made by thermal spraying Basic mechanical and technological properties of continuous fibre-reinforced metal-matrix composites made by thermal spraying are presented. The simple model of continuum theory has been used for the calculation of composite properties parallel to the fibre direction [1]. Taking into account the results obtained the theoretical analysis of composite failure modes and difference between praxis and theory is carried out. Problems concerning the properties measurements of thermally sprayed composites are discussed and their influence on the results is analysed as well. The comparison between the theoretically estimated composite strength and the experimental results is presented. The directions of future research work to improve the composite mechanical properties are also given.