Significant Increase In Density Research Articles

Near seafloor bioluminescence, macrozooplankton and macroparticles at the Mid-Atlantic Ridge

The benthic boundary layer is a region often perceived to be high in faunal abundance and biomass. In this study, we investigated the distribution of near seafloor bioluminescent zooplankton (BL), macrozooplankton (>1cm) and macroparticles (>430μm) at the Northern Mid-Atlantic Ridge at ca. 2500m depth.At sites south of 52°N, the Charlie Gibbs Fracture Zone, BL density increased weakly towards the seafloor. This trend was driven by small bioluminescent crustaceans, comprising ca. 90% of the total BL density. Macroparticle density was coherent with BL density, exhibiting a small increase towards the seafloor. Appendicularians (animals as well as occupied and discarded houses) were the most abundant macrozooplankton, and the only group to show a significant increase in density towards the seafloor. The absence of pronounced increases in BL and macroparticle density, and no increase in macrozooplankton (except appendicularians), towards the seafloor do not support the conventional view of high concentrations of particulate organic matter and zooplankton biomass in the benthic boundary layer relative to overlying waters.

Radial and longitudinal variation of Pinus taeda L. wood basic density in different ages

The wood density is one of the parameters that most affect its properties, which makes it knowledge essential for any use indication. However, due to the high variability of this aspect within the tree, its determination shall consider a sampling throughout the stem. Thus, this study aimed to evaluate the longitudinal and radial variations of Pinus taeda L. wood density for individuals with different ages. To that end, trees with 8, 14, 18 and 26 years old were cut, and discs with 10, 35, 55 and 75% were removed from the tree total height and another in the height corresponding to the chest height diameter– DBH, taken at a 1.30m. From these, samples were collected in three different positions in the pith-bark direction (next to pith, intermediate and next to bark) to determine the density. A significant density increase was observed for older trees samples. A density reduction from the basis to the top and an increase from the pith to the bark was observed.

Development of a ReaxFF reactive force field for tetrabutylphosphonium glycinate/CO2 mixtures.

Carbon dioxide interacts with the ionic liquid tetrabutylphosphonium glycinate, [P(C4)4][Gly], through both physical and chemical absorption. We present a parametrization of the ReaxFF force field for this system that accounts for both chemical and physical interactions. The parametrization was developed from an extensive training set including periodic density functional theory (DFT) calculations of reaction pathways between CO2 and the anion [Gly](-) in the condensed phase, condensed-phase molecular dynamics (MD) configurations, gas-phase CO2-anion and CO2-cation interactions, and gas-phase cluster calculations for intra-ion interactions. The optimized ReaxFF parameters capture the essential features of both physical and chemical interactions between CO2 and [P(C4)4][Gly] as compared with experiments, van der Waals-corrected DFT calculations, or, in the case of physical interactions, classical force field calculations. The probability distributions of the distance between C (from CO2) and N (from the anion) and the CO2 bend angles calculated from MD simulations with the optimized ReaxFF force field are in good general agreement with those from DFT-based MD simulations. We predict that the density of CO2/[P(C4)4][Gly] mixtures increases with increasing CO2 concentration up to at least 50 mol % CO2. We attribute the significant increase in density to the small effective volume occupied by chemically bound CO2 in the mixture. The predicted increase in density may be tested experimentally.

Responses to canopy loss and debris deposition in a tropical forest ecosystem: Synthesis from an experimental manipulation simulating effects of hurricane disturbance

Hurricanes, cyclones, or typhoons are intense and broad-scale disturbances that affect many island and coastal ecosystems throughout the world. We summarize the findings of the articles that compose this special issue of Forest Ecology and Management, which focuses on a manipulative experiment (the Canopy Trimming Experiment, CTE) that simulates two key aspects of hurricane effects in a wet tropical forest. Although previous studies of tropical and subtropical forests have documented changes resulting from hurricanes, it is not clear which of the two simultaneously occurring direct effects of hurricanes—canopy openness or debris deposition—most influence responses. In the Luquillo Experimental Forest (LEF) of Puerto Rico, a multi-disciplinary team of scientists used replicated factorial manipulations to determine the independent and interactive effects of canopy openness and debris deposition on structural and functional characteristics of the forest. The majority of responses were primarily driven by canopy openness rather than by debris deposition. Canopy openness resulted in significant increases in densities of and compositional changes in woody plants, ferns, and some litter arthropods, and significant decreases in coqui frog abundances, leaf decomposition, and litterfall. Debris deposition significantly increased tree basal area and microbial diversity on leaf litter, but these increases were relatively small and ephemeral. Several interactive effects of canopy openness and debris addition emerged, including those involving understory herbivory, canopy arthropod structure, terrestrial gastropod abundances and composition, and soil solution chemistry. Arguably, hurricanes are the most important natural disturbance that affect the LEF, and most characteristics that were measured in the CTE showed evidence of resistance or resilience. By identifying the causal factors affecting secondary successional trajectories of diverse taxa ranging from microbes to vertebrates, biogeochemical attributes, microclimatic characteristics, and measures of ecosystem processes following hurricane disturbance, we better understand tropical forest dynamics resulting from past hurricanes and are better able to predict mechanisms of change related to future hurricanes.

The effect of non-magnetic Al3+ ions on the structure and electromagnetic properties of MgCuZn ferrite

A series of Al substituted MgCuZn ferrite powders with composition Mg0.3Cu0.2Zn0.52AlxFe1.98−xO3.99 (0.00≤x≤0.06) have been synthesized with nano-sized precursor powders through the nitrate–citrate auto-combustion route. These powders were calcined, compacted and sintered at 900°C for 4h. X-ray diffraction patterns show the formation of cubic spinel structure. Infrared spectra indicate two fundamental absorption bands corresponding to the tetrahedral and octahedral complexes, respectively. A significant increase in density and grain size is observed with increasing Al content. The room temperature saturation magnetization increases for x=0.015 and then decreases for further increase in Al substitution. The initial permeability increases with the Al content attributed to the increase in the grain size and density. Curie temperature is found to be dependent on the Al concentration and it decreases due to decrease in the number of super-exchange interactions between Fe3+ ions in the tetrahedral and octahedral sites.

From paper to nanopaper: evolution of mechanical and physical properties

In the present work the evolution of physical and mechanical properties of papers and nanopapers is studied. Handsheets made of eucalyptus fibres reinforced with 0, 25, 50, 75 and 100 wt% of nanofibrillated cellulose (NFC) content were fabricated using a Rapid Kothen-like equipment. The obtained papers and nanopapers were physical- and mechanically-characterized. The results showed a significant increase in density and a reduction of porosity in the samples during their transition from paper to nanopaper; besides, nanopapers were more transparent and smoother than normal papers. These physical changes where more evident with increasing amounts of NFC. Regarding mechanical properties, nanopapers with a 100 wt% content of NFC improved their strength and rigidity in 228 and 317 %, respectively, in comparison with normal papers. The evolution of strength and rigidity from paper to nanopaper was linear in relation to the amount of NFC, which means that the ultimate tensile strength was mainly dependant on nanofibril failure.

Effect of Plastic Deformation on a Dispersion of Omega-Phase and Mechanical Properties of an Al-Cu-Mg-Ag Alloy

Effect of cold rolling prior to ageing on a dispersion of secondary phases and mechanical properties at room temperature for an Al-5.6Cu-0.72Mg-0.5Ag-0.32Mn-0.17Sc-0.12Zr (wt. %) alloy, which was solution treated and water quenched initially, was examined. It was shown that cold working leads to significant increase in density of lattice dislocations that induces the formation discrete agglomerates of the θ′-phase on the {100} planes. Strain of 7% provided increased aspect ratio (length to thickness) of plates that leads to moderate increase of strength. Imposing of higher strains leads to increased lattice dislocation density and the formation of deformation-induced boundaries. Precipitation of the coarse particles of secondary phases on these boundaries takes place. The high yield stress (YS) of 535 MPa and ultimate tensile strength (UTS) of 570 MPa, were attained after cold rolling with a reduction of 80% followed by ageing at 190°C for 2 h. The effect of plastic deformation prior to ageing on the precipitation behavior and strengthening of Al-Cu-Mg-Ag alloy is discussed.

1.10. Postmortem interval estimation: Value of postmortem cerebral CT

Objective After death a series of changes naturally occurs in the human body. Understanding these changes and the contributing factors will lead to a better understanding of the normal process of hypostasis and decomposition, a better estimation of the postmortem interval (PMI) and thus to a better diagnosis of cause and time of death. The aim of this study was to investigate the correlation between the PMI and postmortal intracranial density measurements. Materials and method We retrospectively investigated 61 postmortal cerebral CT scans. We measured the density in Hounsfield units (HU) of the dorsal part of the superior sagittal sinus, vitreous humor left and right and the anterior and posterior horn of lateral ventricles left and right. Correlation between density and PMI was determined using linear regression and is reported using the Pearson׳s correlation coefficient. Results The PMI range was 3.0–45.1h. All densities showed increase over time. This was not significant for the dorsal part of the superior sagittal sinus and vitreous humor (resp. 0.19h per HU; p =0.18; HU 56.1–112.0; Pearson׳s r =0.20 and 0.51h per HU; p=0.12; HU 7.5–29.8; Pearson׳s r =0.23). However, the lateral ventricles showed significant increase of density over time (1.7h per HU; p r =0.65; HU 4.7–18.8). Conclusion The normal postmortal changes are detectable in density of the intracranial structures. This goes especially for the HU increase of liquor during the postmortem interval. This could be of great value for forensic methods to estimate the PMI and needs further prospectively investigation, which we are currently performing.

Mechanical Properties of Structural Lightweight Aggregate Concrete Containing Low Volume Steel Fiber

The use of steel fibers is a good solution for compensating lower mechanical properties of lightweight concrete. However, due to the high specific gravity, the addition of steel fiber increases the density of lightweight concrete. Therefore, there is some reluctance regarding the use of this fiber in lightweight concrete. In this study, to prevent a significant increase in density, low volume fractions of steel fiber (\({\leq}\) 1 %) were used to produce grade 20 structural lightweight aggregate concrete with a dry density of 1,650 kg/m3. Effect of low volume steel fiber on the compressive strength in different curing environments, splitting tensile strength and flexural strength was studied. The test results show that the addition of steel fiber in volume fractions of 0, 0.25, 0.5, 0.75 and 1 % increased its 28-day compressive strength between 14 and 32 %, splitting tensile strength between 21 and 77 % and flexural strength between 6 and 69 %. The effectiveness of steel fiber to increase the compressive strength was more pronounced at later ages than at early age. It was observed that 3 days moist curing is sufficient to gain equivalent compressive strength under standard curing. Adding even a small amount of steel fiber (i.e. 1 % volume fraction) increased the density; however, it was still within the ACI structural lightweight concrete specification. The flexural crack patternsin steel fiber-reinforced concrete beams showed excellent performance of low volume steel fibers in arresting the propagation of cracks.

오디와 누에 섭취가 rats의 저항성 운동에 따른 근육 증가에 미치는 영향

The purpose of this study is to investigate the effects of supplementation of mulberry powder, mulberry extract and silkworm powder during the 8 weeks of resistance exercise on muscle increase of rats. Fifty males, Sprague-Dawley rat, were randomly divided into 5 groups: CON(control group, n = 10), REG(resistance exercise group, n = 10), MP REG(mulberry powder intake and resistance exercise group, n = 10), ME REG(mulberry extract intake and resistance exercise group, n = 10) and SP REG(silkworm powder intake and resistance exercise group, n = 10). After climbing the ladder without weights during the 1 week of adaptation period, the rats in the resistance exercise group were trained to climb a 0.98-m vertical(80 degree incline) ladder with weights in their tail during 7 weeks(10 times each day, 2 days per week). After exercise, the skeletal muscle was extracted from the flexor hallucis longus. The absolute weight of skeletal muscle was measured by the electronic balance and the relative weight of skeletal muscle about the weight was calculated. The strength and density of legs muscle were analyzed by the computed tomography scan. After 8 weeks of resistance exercise, the absolute weight of skeletal muscle wasn't significant, but it increased in MP REG 8%, ME REG 8% and SP REG 10% compared to REG. The relative weight of skeletal muscle increased significantly in SP REG compared to REG (p < 0.05). Additionally, there was a significant increase of density and strength of the forelegs in SP REG compared to CON (p < 0.05). However, there was no significant increase of density and strength of the hind legs. In conclusion, regular resistance exercise made rats muscle increase and there was more muscle increase effected by providing silkworm.

Atributos físicos de um Gleissolo mantido sob dois sistemas de criação: Bovino e Ovinocaprino, localizado no sul do estado do Tocantins.

The excessive animal trampling, together with the lack of conservation practices and adequate soil becomes compacted this, having a significant increase in density, caused by loads or pressures applied in this soil. The Tocantins state is characterized by livestock, particularly cattle, however, there are producers who create small animals such as ovinocaprinos. In literature there are few reports on the effect of trampling on the physical characteristics of an gleysol. This study aimed to evaluate the effect of two systems for livestock, Cattle and ovinocaprino on the physical attributes of an gleysol, located in the southern state of Tocantins. For it was rated the macro and micro-porosity, density and penetration resistance of both systems, separated by compartments. As a result there was a significant difference for the variable density, macro-and micro-porosity and mechanical strength, and it varied depending on the depth of the soil profile.

Tolerance of Sponge Assemblages to Temperature Anomalies: Resilience and Proliferation of Sponges following the 1997–8 El-Niño Southern Oscillation

Coral reefs across the world are under threat from a range of stressors, and while there has been considerable focus on the impacts of these stressors on corals, far less is known about their effect on other reef organisms. The 1997–8 El-Niño Southern Oscillation (ENSO) had notable and severe impacts on coral reefs worldwide, but not all reef organisms were negatively impacted by this large-scale event. Here we describe how the sponge fauna at Bahia, Brazil was influenced by the 1997–8 ENSO event. Sponge assemblages from three contrasting reef habitats (reef tops, walls and shallow banks) at four sites were assessed annually from 1995 to 2011. The within-habitat sponge diversity did not vary significantly across the study period; however, there was a significant increase in density in all habitats. Multivariate analyses revealed no significant difference in sponge assemblage composition (ANOSIM) between pre- and post-ENSO years for any of the habitats, suggesting that neither the 1997–8 nor any subsequent smaller ENSO events have had any measurable impact on the reef sponge assemblage. Importantly, this is in marked contrast to the results previously reported for a suite of other taxa (including corals, echinoderms, bryozoans, and ascidians), which all suffered mass mortalities as a result of the ENSO event. Our results suggest that of all reef taxa, sponges have the potential to be resilient to large-scale thermal stress events and we hypothesize that sponges might be less affected by projected increases in sea surface temperature compared to other major groups of reef organisms.

Intrauterine undernutrition programs the hypothalamic proteome of female rats

Undernutrition in early life may cause adulthood obesity with disruption of energy homeostasis control. We analyzed the hypothalamic proteome of adult female rats born from dams fed ad libitum or restricted to 50% of ad libitum intake during gestation. Control and restricted progeny were studied at age 4 months. Hypothalamic proteins were analyzed by two‐dimensional gel electrophoresis and MALDI‐TOF/TOF–MS. MASCOT server was used to search Swiss‐Prot protein database. Only proteins with false discovery rate of 0% were considered in the results analysis. The restricted rats had normal body weight and insulin levels with increased fat pads weight and glycemia. Significant density increase of 10 spots and decrease of 9 spots was found. Six overexpressed and 4 under‐expressed proteins were identified. They are enzymes of energy metabolism pathways, and proteins of redox regulation, inflammatory, and cell communication processes. Female rats undernourished intra uterus developed into obese adults and presented alterations of hypothalamic protein profile that may be involved in the disturbances leading to obesity

Dehydration-Induced Amorphous Phases of Calcium Carbonate

Amorphous calcium carbonate (ACC) is a critical transient phase in the inorganic precipitation of CaCO3 and in biomineralization. The calcium carbonate crystallization pathway is thought to involve dehydration of more hydrated ACC to less hydrated ACC followed by the formation of anhydrous ACC. We present here computational studies of the transition of a hydrated ACC with a H2O/CaCO3 ratio of 1.0 to anhydrous ACC. During dehydration, ACC undergoes reorganization to a more ordered structure with a significant increase in density. The computed density of anhydrous ACC is similar to that of calcite, the stable crystalline phase. Compared to the crystalline CaCO3 phases, calcite, vaterite, and aragonite, the computed local structure of anhydrous ACC is most-similar to those of calcite and vaterite, but the overall structure is not well described by either. The strong hydrogen bond interaction between the carbonate ions and water molecules plays a crucial role in stabilizing the less hydrated ACC compositions compared to the more hydrated ones, leading to a progressively increasing hydration energy with decreasing water content.

Changes in soil quality after subsequent establishment of Chromolaena odorata fallows in humid savannahs, Ivory Coast

Abstract In the buffer zone of the Lamto Reserve, a protected area located in the forest-savannah transitional zone in central Ivory Coast, the exotic shrub Chromolaena odorata has invaded abandoned fields and degraded forests. As a result, they have turned into thickets that are used by local farmers as natural fallows to enhance soil fertility for food production. However, information about their impact on soil is scanty and investigations focusing exclusively on baseline data on C. odorata fallows in humid savannahs are still lacking. This study was designed to assess changes in soil physical, chemical and biological properties after the establishment of C. odorata fallows in humid savannahs of Ivory Coast. Sampling sites were selected such that a portion of C. odorata fallow was located next to the shrub savannah, the most common natural ecosystem in the area. Results revealed a rise of soil organic carbon (+ 27.9%), total nitrogen (+ 36.7%), total phosphorus (+ 56.8%), extractable calcium (+ 68.3) and magnesium (+ 140.3%) in the first 10 cm of soil beneath the C. odorata fallow relative to the savannah. Furthermore, the fallow was associated with high N-mineral pool as N-NO3− and N-NH4+ content increased at + 72.5% and + 71.5%, respectively. The infiltration capacity of water under C. odorata-based fallow was markedly high and soil macroinvertebrates, mainly earthworms, showed significant increases in density and biomass. The large quantity of good quality standing biomass produced by C. odorata is likely the main factor controlling the improvement of soil quality. The results suggest that there are merits for the integration of C. odorata fallow in a cropping system for sustainable food production in the buffer zone of Lamto Reserve. This can also help to reduce pressure on forest islands.

Extract of white button mushroom affects skin healing and angiogenesis

White button mushroom extract was examined in this study on (1) its potential effect on angiogenesis in chorioallantoic culture and (2) its recovering effect on the skin after injury in the ICR mice. Methods used included TUNEL assay on apoptosis, immunohistochemistry for vascular endothelial growth factor (VEGF), proliferative cell nuclear antigen (PCNA), epidermal growth factor (EGF), transforming growth factor β (TGF-β), and immune factor CD4 and western blotting. The results of chorioallantoic culture showed that the mushroom treatment led to significant increase in densities of VEGF sites. In the skin injury, ICR mice model increased EGF, PCNA, and collagen fibers, along with decrease of TUNEL positive apoptotic cells and limited reaction of TGF-β and CD4 indicated that white button mushroom extract appeared to have beneficial effects on skin in regeneration and after injury.

Influence of corticostriatal δ-opioid receptors on abnormal involuntary movements induced by L-DOPA in hemiparkinsonian rats

Chronic l-3,4-dihydroxyphenylalanine (l-DOPA) treatment of Parkinson's disease induces in time numerous side effects, such as abnormal involuntary movements called l-DOPA-induced dyskinesias (LIDs). An involvement of glutamate transmission, dopamine transmission and opioid transmission in striatal output pathways has been hypothesized for the induction of LIDs. Interestingly, our previous experiments indicated that some striatal δ-opioid receptors are located on terminals of glutamatergic corticostriatal neurons and that stimulation of these receptors modulates the release of glutamate and dopamine. The present study was performed to test the involvement of δ-opioid receptors, and more precisely of those located on corticostriatal neurons, in abnormal involuntary movements induced by l-DOPA in hemiparkinsonian rats. The effects of a selective agonist, [d-Pen2, d-Pen5]-enkephalin (DPDPE) and a selective antagonist (naltrindole) of δ-opioid receptors on LIDs were investigated in animals submitted or not to a corticostriatal deafferentation. Our results indicate that DPDPE and naltrindole respectively enhanced and reduced LIDs in animals in which the ipsilateral cortex was preserved intact. However, the lesion of the ipsilateral cortex prevented the stimulant effect of DPDPE on LIDs. The [3H]-DPDPE binding to striatal membranes prepared from the whole striatum was also studied. A significant increase in density of δ-opioid receptors was found in the striatum of dyskinetic animals as compared to non-dyskinetic animals but this difference was abolished by the corticostriatal deafferentation. These results indicate that δ-opioid transmission modulates the expression of LIDs in rodents and suggest that the δ-opioid receptors involved in this effect are located on terminals of corticostriatal neurons.

Differential effect of zoledronic acid on normal trabecular and cortical bone density in oncologic patients with bone metastases

PurposeTo evaluate bone density changes at the level of normal bone and bone metastases after zoledronic acid (ZA) treatment in oncologic patients. Materials and methodsWe retrospectively evaluated 72 consecutive adult patients with histologically confirmed solid tumors with at least 1 newly diagnosed bone metastatic lesion. Bone metastases were diagnosed by bone scans and confirmed with computed tomography (CT). Patients received intravenous ZA, 4mg, by 15-min infusion every 28 day through a peripheral or a central venous access and were monitored for at least 3 months and a maximum of 24 months. Bone density was determined at the level of bone metastases and at the level of normal trabecular and cortical bone using a ROI-based approach. ResultsA significant increase was demonstrated at the level of normal trabecular bone of the calvarium and the femoral neck. No significant increase of density was observed at the level of the normal cortical bone. Bone metastases showed a significant increase in CT density as compared to baseline up to 24 months after zoledronic acid. ConclusionWe have found that long term treatment with ZA increases trabecular bone density in oncologic patients whereas normal cortical bone changes are not detectable.

Efficacy of retinol palmitate eye drops for dry eye in rabbits with lacrimal gland resection

PurposeWe examined the efficacy of retinol palmitate (VApal) for dry eyes using dry eye model rabbits whose lacrimal glands were resected.Materials and methodsAfter alkaline injury on keratoconjunctival epithelium, VApal eye drops were administered 6 times a day for 7 days. The efficacy of VApal was also compared with that of 0.1% hyaluronic acid eye drops.ResultsThe fluorescein staining and rose bengal scores showed a significant decrease compared with the score in the vehicle group at 7 days (P < 0.05) in the 1000 IU/mL VApal group and at both 3 days (P < 0.05) and 7 days (P < 0.01) in the 1500 IU/mL VApal group. Histological examination revealed recovery of the corneal epithelium, and PAS staining disclosed the recovery of mucin-producing lower palpebral conjunctival goblet cells after 7 days in the 1500 IU/mL VApal group compared with the vehicle group. Results from impression cytology showed a significant increase in density of conjunctival goblet cells compared with that in the vehicle group after 7 days in the 1000 IU/mL VApal group and after 3 and 7 days in the 1500 IU/mL VApal group. There were no significant changes in tear flow in either group. Topical application of VApal at 1500 IU/mL showed greater improvement than 0.1% hyaluronic acid in both fluorescein and rose bengal score and in the density of conjunctival goblet cells.ConclusionIt is suggested that VApal is effective for the improvement of keratoconjunctival epithelial damage associated with tear abnormalities, such as dry eyes.

Anatomy of corpus callosum in prenatally malnourished rats

The effect of prenatal malnutrition on the anatomy of the corpus callosum was assessed in adult rats (45-52 days old). In the prenatally malnourished animals we observed a significant reduction of the corpus callosum total area, partial areas, and perimeter, as compared with normal animals. In addition, the splenium of corpus callosum (posterior fifth) showed a significant decrease of fiber diameters in the myelinated fibers without changing density. There was also a significant decrease in diameter and a significant increase in density of unmyelinated fibers. Measurements of perimeter's fractal dimensions from sagittal sections of the brain and corpus callosum did not show significant differences between malnourished and control animals. These findings indicate that cortico-cortical connections are vulnerable to the prenatal malnutrition, and suggest this may affect interhemispheric conduction velocity, particularly in visual connections (splenium).