Proton NMR relaxometry as a useful tool to evaluate swelling processes in peat soils

Dramatic physical and physico-chemical changes in soil properties may arise due to temperature and moisture variations as well as swelling of soil organic matter (SOM) under constant conditions. Soil property variations may influence sorption/desorption and transport processes of environmental contaminants and nutrients in natural-organic-matterrich soils. Notwithstanding the studies reported in literature, a mechanistic model for SOM swelling is unavailable yet. The objective of the present study was the evaluation of the swelling of peat soils, considered as SOM models, by 1H NMR relaxometry and differential scanning calorimetry (DSC). Namely, information on the processes governing physical and physicochemical changes of peat during re-hydration were collected. The basic hypothesis of the present study was that the changes are slow and may affect water state as well as amounts of different water types into the peats. For this reason, such changes can be evidenced through the variations of mobility and thermal behaviour of the involved H2O molecules by using 1H NMR relaxometry and DSC. According to the experimental results, a mechanistic model, describing the fundamental processes of peat swelling, was obtained. Two different peats re-wetted at three temperatures were used. The swelling process was monitored by measuring spin-spin relaxation time (T2) over a hydration time of several months. Moreover, DSC, T1 – T2 and T2 – D correlation measurements were done at the beginning and at the end of the hydration. Supplementary investigations were also done in order to discriminate between the swelling effects and the contributions from soil solution, internal magnetic field gradients and/or soil microorganisms to proton relaxation. All the results revealed peat swelling. It was evidenced by pore size distribution changes, volumetric expansion and redistribution of water, increasing amounts of nonfreezable and loosely bound water, as well as formation of gel phases and reduction of the translational and rotational mobility of H2O molecules. All the findings implied that changes of the physical and physicochemical properties of peats were obtained. In particular, three different processes having activation energies comprised in the interval 5 – 50 kJ mol-1 were revealed. The mechanistic model which was, then, developed included water reorientation in bound water phases, water diffusion into the peat matrix and reorientation of SOM chains as fundamental processes governing SOM swelling. This study is of environmental significance in terms of re-naturation and re-watering of commercially applied peatlands and of sorption/desorption and transport processes of pollutants and nutrients in natural organic matter rich soil

A fast 2D image reconstruction algorithm from 1D data for the Gaia mission

A fast 2-dimensional image reconstruction method is presented, which takes as input 1-dimensional data acquired from scans across a central source in different orientations. The resultant reconstructed images do not show artefacts due to non-uniform coverage in the orientations of the scans across the central source, and are successful in avoiding a high background due to contamination of the flux from the central source across the reconstructed image. Due to the weighting scheme employed this method is also naturally robust to hot pixels. This method was developed specifically with Gaia data in mind, but should be useful in combining data with mismatched resolutions in different directions.Comment: accepted (18 pages, 13 figures) will appear in Experimental Astronom

A reduced-order model of three-dimensional unsteady flow in a cavity based on the resolvent operator

A novel reduced-order model for nonlinear flows is presented. The model arises from a resolvent decomposition in which the nonlinear advection terms of the Navier-Stokes equation are considered as the input to a linear system in Fourier space. Results show that Taylor-G\"ortler-like vortices can be represented from a low-order resolvent decomposition of a nonlinear lid-driven cavity flow. The present approach provides an approximation of the fluctuating velocity given the time-mean and the time history of a single velocity probe

Steady streamwise transpiration control in turbulent pipe flow

A study of the the main features of low- and high amplitude steady streamwise wall transpiration applied to pipe flow is presented. The effect of the two transpiration parameters, amplitude and wavenumber, on the flow have been investigated by means of direct numerical simulation at a moderate turbulent Reynolds number. The behaviour of the three identified mechanisms that act in the flow: modification of Reynolds shear stress, steady streaming and generation of non-zero mean streamwise gradients, have been linked to the transpiration parameters. The observed trends have permitted the identification of wall transpiration configurations able to reduce or increase the overall flow rate in -36.1% and 19.3% respectively. A resolvent analysis has been carried out to obtain a description of the reorganization of the flow structures induced by the transpiration

Effect of dithiocarbamate thiram on Wistar rat growth plate and articular cartilage

Avaliou-se o efeito do tirame, ditiocarbamato largamente utilizado na agricultura como antifúngico e repelente de roedores, na ossificação endocondral de mamíferos, usando, como modelo, ratos Wistar. Não foram observadas lesões na cartilagem articular, nem nas placas de crescimento, o que pode ser atribuído à dose utilizada e à duração do ensaio. A diminuição da altura da placa de crescimento nos animais aos quais foi administrado o tirame parece traduzir o atraso verificado no crescimento em geral, e não um efeito específico na cartilagem, uma vez que as diferentes zonas da placa epifisária mantiveram as proporções dos animais do grupo-controle. Embora não tenham sido verificados, no presente trabalho, os efeitos registrados para outras espécies nos tecidos cartilaginosos, sugere-se a avaliação dos efeitos crónicos do tirame no crescimento e no desenvolvimento dos ossos longos em mamíferos

Identifikasi Patahan Manado dengan Menggunakan Metode Geolistrik Resistivitas Konfigurasi Wenner-schlumberger di Desa Watutumou II Kecamatan Kalawat Kabupaten Minahasa Utara

IDENTIFIKASI PATAHAN MANADO DENGAN MENGGUNAKAN METODE GEOLISTRIK RESISTIVITAS KONFIGURASI WENNER-SCHLUMBERGER DI DESA WATUTUMOU II KECAMATAN KALAWAT KABUPATEN MINAHASA UTARAABSTRAK Telah dilakukan penelitian tentang Identifikasi Patahan Manado yang melewati Desa Watutumou II Kecamatan Kalawat Kabupaten Minahasa Utara. Penelitian dilakukan dengan menggunakan alat Geolistrik Resistivitas multichannel and multielectrode resistivity and IP meter 46 simultaneous channel merek MAE X612-EM Konfigurasi Wenner-Schlumberger. Pengambilan data dilakukan pada 4 lintasan, 3 lintasan panjang bentangannya sebesar 480 meter, dan 1 lintasan panjang bentangannya sebesar 240 meter. Posisi lintasan disusun parallel satu dengan yang lain. Pengolahan data dilakukan dengan mengunakan perangkat lunak RES2DINV, menghasilkan gambar tampang lintang 2 dimensi citra bawah permukaan tanah pada lokasi penelitian. Analisis menunjukan bahwa pada semua lintasan rekahan teridentifikasi pada jarak 20 meter dari jalur Patahan Manado, dengan kedalaman 0 - 30 meter dari permukaan tanah, dan harga resistivitas sebesar 0 – 80 Ωm. Kata Kunci : Geolistrik, Wenner-Schlumberger, Patahan Manado. IDENTIFICATION OF MANADO FAULT BY USING GEOELECTRICAL METHOD OF WENNER-SCHLUMBERGER RESISTIVITY CONFIGURATION IN THE VILLAGE OF WATUTUMOU II, DISTRICT OF KALAWAT, NORTH MINAHASA REGANCY ABSTRACT Has done research on the identification of Manado Fault which passes through the village of Watutumou II Kalawat district of North Minahasa Regency. Research is done by using the tool of Geoelectrical Resistivity multichannel and multielectrode and IP meter 46 simultaneous channel Wenner-Schlumberger configuration with brand of MAE X612-EM. The data collection was carried out on 4 lanes, where 3 of them have a range of length of 480 meter and 1 lane with length of 240 meter. Each of these lanes was assembled paralelly one another. The data processing was held with assistance of RES2DINV software. Its result gave an overview about the 2-dimensional transection of beneath-surface imaging in the research zone. According to the analysis outcome, a fracture identified at 20 meter from the Manado fault, with a depth of 0-30 meter above the ground\u27s surface, and with an approximated value of resistivity of 0 - 80 Ωm

Strain amplitude response and the microstructure of PA/clay nanocomposites

Polyamide 6/clay nanocomposites (PAn, where n is the mass fraction of clay) with various clay loading were prepared by melt compounding in a twin screw extruder. Exfoliation of clay in a PA matrix was confirmed by X-ray diffraction. Strain amplitude response of PAn in both melt and solution states has been investigated. In the melt state, critical strain amplitude of PAn is sensitive to strain amplitude response and decrease logarithmically with increasing clay loading. The elastic moduli (G′) of PAn are reversible under frequency loop sweeps. Comparisons of strain amplitude response in both melt and solution states have been conducted. Two different responses have been observed: strain thinning in the melt state and weak strain overshoot in the solution state. FTIR studies show that amide II band of PAn shifts toward high wavenumbers, but amide I band and N–H stretching vibration are independent of clay loading. We suggest that two types of strain amplitude response of PAn can be explained: strain thinning which is dominant in PAn caused by physical adsorption and entanglement of PA chains on nanoclays and weak strain overshoot caused by weak bonds between PA chains and nanoclays

Pengaruh Angin Dan Kelembapan Atmosfer Lapisan Atas Terhadap Lapisan Permukaan Di Manado

Penelitian ini mengkaji lebih dalam kondisi angin dan kelembapan udara pada saat musim hujan dan musim kemarau di Manado dengan menggunakan data di lapisan permukaan dan data udara atas dari Stasiun Meteorologi Sam Ratulangi Manado. Tujuan utama dari penelitian ini adalah mendapatkan hubungan antara kondisi angin dan kelembapan lapisan atas terhadap lapisan permukaan, sehingga dapat memprakirakan kondisi angin dan kelembapan lapisan permukaan dengan berdasarkan keadaan lapisan atas. Metode yang digunakan adalah mengkomponenkan angin dalam arah utara-selatan dan timur-barat, selanjutnya mencari keterkaitan dengan menggunakan teknik korelasi. Hasil penelitian ini menunjukkan pada saat musim hujan angin pada lapisan 1500 m dan angin di lapisan permukaan memiliki arah yang sama dan saling menguatkan untuk komponen timur-barat (zonal) dengan koefisien korelasi r=0,56, sedangkan pada saat musim kemarau angin pada lapisan 1500 m dan angin di lapisan permukaan memiliki arah yang sama dan saling menguatkan untuk komponen utara-selatan (meridional) dengan koefisien korelasi r=0,45. Keterkaitan yang cukup kuat antara angin dengan kelembapan terjadi pada komponen V (meridional) yaitu, pada saat musim hujan, semakin besar kecepatan angin komponen negatif (utara) semakin besar pula kelembapan udara di lapisan permukaan, dengan koefisien korelasi benilai positif r=0.40. Pada saat musim kemarau, semakin besar kecepatan angin komponen positif (selatan) semakin kecil kelembapan udara di lapisan permukaan, dengan koefisien korelasi bernilai negatif r=— 0,48.This study examined the wind and humidity condition in the rainy season and dry season in Manado by using the data in surface layer and upper air data from the Sam Ratulangi Meteorological Station. The primary objective of this study was to find the relationship between wind condition and upper layer humidity to surface layer, using correlation technique, in order to predict wind condition and humidity of the surface layer based on the condition of the upper layer. The results showed that, during the rainy season, the wind at layer 1500 m and surface layer had the same direction and mutually reinforced for the east-west component (zonal) with correlation coefficient r=0.56, whereas during the dry season, wind at layer 1500 m and at surface layer had the same direction and mutually reinforced for the north-south component (meridional) with correlation coefficient r=0.45. A relationship between wind and humidity was found at V component (meridional), which was, at rainy season, the higher the wind speed of negative component (north) the higher the humidity at surface layer with positive correlation coefficient r=0.40. At dry season, the higher the wind speed of positive component (south), the lower the humidity at the surface layer, with negative correlation coefficient r=—0.48

Apical endosomes isolated from kidney collecting duct principal cells lack subunits of the proton pumping ATPase.

Endocytic vesicles that are involved in the vasopressin-stimulated recycling of water channels to and from the apical membrane of kidney collecting duct principal cells were isolated from rat renal papilla by differential and Percoll density gradient centrifugation. Fluorescence quenching measurements showed that the isolated vesicles maintained a high, HgCl2-sensitive water permeability, consistent with the presence of vasopressin-sensitive water channels. They did not, however, exhibit ATP-dependent luminal acidification, nor any N-ethylmaleimide-sensitive ATPase activity, properties that are characteristic of most acidic endosomal compartments. Western blotting with specific antibodies showed that the 31- and 70-kD cytoplasmically oriented subunits of the vacuolar proton pump were not detectable in these apical endosomes from the papilla, whereas they were present in endosomes prepared in parallel from the cortex. In contrast, the 56-kD subunit of the proton pump was abundant in papillary endosomes, and was localized at the apical pole of principal cells by immunocytochemistry. Finally, an antibody that recognizes the 16-kD transmembrane subunit of oat tonoplast ATPase cross-reacted with a distinct 16-kD band in cortical endosomes, but no 16-kD band was detectable in endosomes from the papilla. This antibody also recognized a 16-kD band in affinity-purified H+ ATPase preparations from bovine kidney medulla. Therefore, early endosomes derived from the apical plasma membrane of collecting duct principal cells fail to acidify because they lack functionally important subunits of a vacuolar-type proton pumping ATPase, including the 16-kD transmembrane domain that serves as the proton-conducting channel, and the 70-kD cytoplasmic subunit that contains the ATPase catalytic site. This specialized, non-acidic early endosomal compartment appears to be involved primarily in the hormonally induced recycling of water channels to and from the apical plasma membrane of vasopressin-sensitive cells in the kidney collecting duct

The relationship between HIV seroconversion illness, HIV test interval and time to AIDS in a seroconverter cohort.

Seroconversion illness is known to be associated with more rapid HIV disease progression. However, symptoms are often subjective and prone to recall bias. We describe symptoms reported as seroconversion illness and examine the relationship between illness, HIV test interval (time between antibody-negative and anibody-positive test dates) and the effect of both on time to AIDS from seroconversion. We used a Cox model, adjusting for age, sex, exposure group and year of estimated seroconversion. Of 1820 individuals, information on seroconversion illness was available for 1244 of whom 423 (34%) reported symptomatic seroconversion. Persons with a short test interval (< or = 2 months) were significantly more likely to report an illness than people with a longer interval (OR 6.76, 95% CI 4.75-9.62). Time to AIDS was significantly faster (P = 0.01) in those with a short test interval. The HIV test interval is a useful replacement for information on seroconversion illness in studies of HIV disease progression