On experimental studies of longitudinal and flexyral wawe propagations: An annotated bibliography

Experimental investigations in the field of longitudinal wave propagation in beams are plentiful; however, experimental studies of flexural wave propagation problems are scarce and are restricted mainly to uniform and infinite structures where the effects of reflected waves are not generally included. This review is mostly restricted to low velocity impact and does not cover the so-called high velocity impact such as those of bullets and explosives. In addition to a brief survey of classical work related to impact, this article covers publications related to experimental studies of longitudinal and flexural elastic waves due to impact. This includes the longitudinal, central as well as eccentric impact and transverse impact of two bars and the impact achieved by sphere impinging on a beam. Many workers used experimental findings to study the adequacy of various theoretical solutions of the wave propagation problem such as those by Pochhammer and Chree, Euler-Bernoulli, and the Timoshenko beam theory. The revival of interest in the recent years is due to, among other things, the advancement of experimental equipment and measurement techniques for data acquisition of stress waves and associated signals. An important application of transient waves is their use for the determination of material properties under various loading conditions and strain rates that can be studied by the split Hopkinson pressure bar techniques. The problem of longitudinal and flexural waves in bars with discontinuities of cross section are covered, and some publications on fracture of materials due to bending waves are also included. Experimental investigations demonstrate the effect of abrupt change of cross section and/or material properties on reflected and transmitted waves where reflections are to be taken into consideration when estimating the level of stresses and strains in finite beam with discontinuities. In the field of flexural wave propagation, comparison of theoretical predictions with experimental results verified and validated the adequacy of the Timoshenko theory for the determination of bending strain in finite structures, a one-dimensional theory that takes into account the effect of shear deformation and rotatory inertia

A study of warm-up and injury in hamstring muscles

This project is the first to investigate blood perfusion in the human hamstrings during isometric exercise with a near infrared spectroscopy (NIRS). A Kin Com dynamometer has been used to fix the knee positions and to measure torques during contractions. Both the NIRS optodes and the electromyography (EMG) electrodes were attached to the skin over the hamstrings. Previous studies used a NIRS to measure muscle blood flow in the forearm, quadriceps and calf muscles. The changes in haemoglobin concentrations were calculated using Spike 2 software. A total of 46 male volunteers participated in the four series of experiments described in this thesis. The following overall conclusions can be drawn: perfusion decreases in the hamstrings during contractions and then returns to normal levels after a period of time, changing the limb position at which the contractions are made does not affect the perfusion, warm-up exercises increase in blood perfusion for 8 minutes at 30 and 40% of MVC. The perfusion did not significantly change during an episode of DOMS or in the injured and non-injured limbs. These conclusions show the importance of warm-up before sports activities but not necessarily avoid injury. It can be concluded that there is no association between such conditions with hamstring injuries. The maintained perfusion at different conditions is a positive finding as the perfusion is not restricted indicating good delivery of oxygen despite muscle injury

Anatomical Studies of Medicinal Plant Fumaria densiflora in Iraq

The anatomical characters of the leaf, stem and fruits of Fumaria densiflora of Papaveraceae family were studied by scanning electron and light microscopy. The results showed that the wall cells of adaxial and abaxial epidermis was thick with straight- sinuate anticlinal cell walls. Both surface have stomatal types of anomocytic, anisocytic and hemiparacytic. Leaf mesophyll consists of 1- 2 layers of palisade cells under the superior epidermis thickness rang 121.44 um and 3 or 6 layers of spongy tissue under the palisade layer. Cross sections of stems are pentagonal- shaped in outline and having five prominent angles.Fumaria fruits are tetragonal in shaped (fruit ribs are four). The external area included 2-4 layers of chlorenchyma cells as well as several layers of hypodermal collenchyma cells were recognized below the epidermis. Laticifer tubes could be seen in the sclerenchymatous sheath of the vascular bundles, the fruit wall, placenta and internal parenchyma layers. Keywords: Papaveraceae, Fumaria densiflora, leaves, stem, fruits

PHYSICOCHEMICAL PROPERTIES OF ALOE VERA GEL AND ITS UTILIZATION IN PREPARING SYNBIOTIC FERMENTED MILK WITH Bifidobacterium Lactis BB-12

This study was aimed to investigate the physicochemical structure of fresh and dried Aloe Vera gel (AVG) and its adequacy as a prebiotic in the preparation of Synbiotic fermented milk with Bif. Lactis BB-12, in addition to its effect on the survival of these bacteria during 28 days of cold storage. The results indicated that the yield of the gel was % 64.56±1.157, and the moisture content, total solids (TS) and total soluble solids (TSS) in the fresh gel were % 98.23±0.0816, %1.777±0.0103 and % 1.56±0.0816 respectively. The pH of fresh and dried gel was 4.48±0.0105 and 4.63±0.01, respectively, meanwhile the acidity was 0.083±0.00121 and 0.058±0.0083, respectively (expressed as malic acid). Addition of 0.03% , 0.05% of dried and 3% ,5% of fresh AVG to treatments under study which represented as B1, B2, B3, and B4 respectively, reduced the generation time (GT) to 71.91, 68.49, 80.14 and 95.17 min, respectively as compared to that of the control treatment B0 (AVG free), which was 112.52 min. The pH value decreased in treatments B0, B1, B2, B3, and B4 to 4.45, 4.41, 4.36, 4.39 and 4.38, respectively, as the acidity increased to 1.13, 1.18, 1.26, 1.20 and 1.21%, respectively

Analysis of microstructure effects on edge crack of thin strip during cold rolling

Edge cracks in cold rolling of the thin strip affect the strip quality and productivity significantly. In this study, an experimental and mechanical investigation on microstructures has been carried out to study the edge crack formation during cold rolling of the thin strip. The effects of the feed material microstructures on the edge crack evolution were studied employing optical microscopy and scanning electron microscopy (SEM). Experimental observation indicates that fine grain occurs in hot-rolled microstructure and coarse grain is produced in ferritic rolled microstructure. Different grain sizes affect significantly the formation mechanics of the microcrack, crack initiation, and orientation of crack extension. The grain size and grain boundaries effects on crack retardation are discussed also during edge crack initiation. During the crack growth in coarse grain, most edge crack tips will blunt, which improves the crack toughness by causing less stress concentration. Overall, the fine microstructure shows a good crack initiation resistance, whereas the coarse microstructure has a better resistance to crack propagation. This research provides additional understanding of the mechanism of microstructure influence on edge crack evolution of cold strip rolling, which could be helpful for developing defect-free thin strip

A systematic review of the incidence of schizophrenia: the distribution of rates and the influence of sex, urbanicity, migrant status and methodology

BACKGROUND: Understanding variations in the incidence of schizophrenia is a crucial step in unravelling the aetiology of this group of disorders. The aims of this review are to systematically identify studies related to the incidence of schizophrenia, to describe the key features of these studies, and to explore the distribution of rates derived from these studies. METHODS: Studies with original data related to the incidence of schizophrenia (published 1965–2001) were identified via searching electronic databases, reviewing citations and writing to authors. These studies were divided into core studies, migrant studies, cohort studies and studies based on Other Special Groups. Between- and within-study filters were applied in order to identify discrete rates. Cumulative plots of these rates were made and these distributions were compared when the underlying rates were sorted according to sex, urbanicity, migrant status and various methodological features. RESULTS: We identified 100 core studies, 24 migrant studies, 23 cohort studies and 14 studies based on Other Special Groups. These studies, which were drawn from 33 countries, generated a total of 1,458 rates. Based on discrete core data for persons (55 studies and 170 rates), the distribution of rates was asymmetric and had a median value (10%–90% quantile) of 15.2 (7.7–43.0) per 100,000. The distribution of rates was significantly higher in males compared to females; the male/female rate ratio median (10%–90% quantile) was 1.40 (0.9–2.4). Those studies conducted in urban versus mixed urban-rural catchment areas generated significantly higher rate distributions. The distribution of rates in migrants was significantly higher compared to native-born; the migrant/native-born rate ratio median (10%–90% quantile) was 4.6 (1.0–12.8). Apart from the finding that older studies reported higher rates, other study features were not associated with significantly different rate distributions (e.g. overall quality, methods related to case finding, diagnostic confirmation and criteria, the use of age-standardization and age range). CONCLUSIONS: There is a wealth of data available on the incidence of schizophrenia. The width and skew of the rate distribution, and the significant impact of sex, urbanicity and migrant status on these distributions, indicate substantial variations in the incidence of schizophrenia

Neuroanatomical Pattern of Mitochondrial Complex I Pathology Varies between Schizophrenia, Bipolar Disorder and Major Depression

BACKGROUND:Mitochondrial dysfunction was reported in schizophrenia, bipolar disorderand major depression. The present study investigated whether mitochondrial complex I abnormalities show disease-specific characteristics. METHODOLOGY/PRINCIPAL FINDINGS:mRNA and protein levels of complex I subunits NDUFV1, NDUFV2 and NADUFS1, were assessed in striatal and lateral cerebellar hemisphere postmortem specimens and analyzed together with our previous data from prefrontal and parieto-occipital cortices specimens of patients with schizophrenia, bipolar disorder, major depression and healthy subjects. A disease-specific anatomical pattern in complex I subunits alterations was found. Schizophrenia-specific reductions were observed in the prefrontal cortex and in the striatum. The depressed group showed consistent reductions in all three subunits in the cerebellum. The bipolar group, however, showed increased expression in the parieto-occipital cortex, similar to those observed in schizophrenia, and reductions in the cerebellum, yet less consistent than the depressed group. CONCLUSIONS/SIGNIFICANCE:These results suggest that the neuroanatomical pattern of complex I pathology parallels the diversity and similarities in clinical symptoms of these mental disorders