Laboratory Analysis Of Samples Research Articles

Assessment of groundwater potential and quality using geophysical and physicochemical methods in the basement terrain of Southwestern, Nigeria

An integrated approach involving geophysical and physicochemical methods was undertaken to assess the potential availability of groundwater and its quality was carried out at Akole, Abeokuta Southwestern Nigeria. A combination of electrical resistivity and natural electric field methods were used in delineating the sub-surface lithology, determining potential groundwater-bearing zones, and the potential availability of groundwater for a community water supply. Laboratory analyses of samples from existing wells in the area was also carried out to determine the groundwater quality index (GWQI). Four vertical electrical sounding (VES) stations and nine profiles were surveyed using the Omega Campus and PQWT 150 instruments, respectively. The VES results delineated a maximum of five geo-electric sub-surface layers. A sudden change in the stratigraphy view of the rock formation from soft to very hard formation was observed in profile map L2. Profile map L7 and VES 2 has the highest potential for future groundwater exploration. Areas under VES 3 and profile maps L2, L3, L4, L5, L6, L8 and L9 are categorized as having a “medium” groundwater potential while the low yield water potential are areas under VES 1 and 4 and, profiles maps L1 and L10. The majority of groundwater in the weathered/fractured aquifer of the study area is slightly acidic. The GWQI values were less than 100, an indication that the analysed water samples fall within the “excellent” and “good” quality categories, implying that the groundwater is fit for domestic purposes. A combination of geophysical and physicochemical techniques has been successfully used to provide useful information for the assessment of groundwater potential and quality of the community.

A Computational Study of Effect of Thickness on Mild Steel Fracture

Abstract Fracture and crack propagation in various materials have always attracted the attention of researchers. Therefore, an investigation of the fracture of construction steel as one of the most extensively used materials in the industry is of necessity. Numerical modeling has been always a complementary aid to the laboratory sample analysis. One important issue is to study the behavior of laboratory specimens based on their dimensions, which finds further significance in fracture problems. In the current research, the effect of sample thickness on the crack behavior is investigated via a compact tension specimen. Accordingly, using numerical result validation, the behavior of the numerical samples along the thickness is examined and used as a complement to the experimental results. By modeling and analyzing numerical samples with different thicknesses (0.1 < B/W < 2), an equation is proposed. The equation can be used to determine in what percentage of the thickness from the free edge the behavior is either plane stress or plane strain.

Pulse amplitude modulation as an indicative method for monitoring compliance of ballast water management – Walz Water PAM instrument test

Vessels are considered one of the primary pathways for the transfer of harmful aquatic organisms and pathogens. The D-2 Regulation of the Ballast Water Management Convention specifies the maximum number of organisms per unit volume in order to prevent their spread and transfer, and the introduction of harmful aquatic organisms and pathogens around the globe. The Convention also requires an inspection of every ship’s ballast water in order to verify compliance with the requirements. Inspectors take samples of ballast water and perform quick analyses on board using indicative instruments. We evaluated the appropriateness of the Walz Water PAM instrument for indicative analysis of ballast water. The instrument estimates the phytoplankton biomass and its photochemical efficiency. The instrument measurements were compared to the results of detailed laboratory analyses of samples for phytoplankton cells in the size range 10–50 µm and with minimum diameter, as addressed by the Regulation D-2. The instrument correctly evaluated all 19 compliant samples from the detailed analyses and 88 of 95 non-compliant samples from detailed analyses (93%). We can thus conclude that Walz Water PAM is a suitable tool for the indicative analysis of vessels’ ballast water.

ANALYSIS OF PEDOLOGICAL FACTORS AND USCS IN THE CONTACT AREA OF ĐAKOVO LOESS PLATEAU AND DILJ GORA, CROATIA

The pedological factors concerning the Unified Soil Classification System (USCS) in the contact area of Đakovo loess plateau and Dilj gora have been explored. The study was carried out to create a cross-country mobility map for vehicles. The spatial GIS analysis included soil units of Basic Soil Map (BSM) at a scale of 1:50000, which, according to the World Reference Base (WRB), contain within themselves the distribution of soil units, particle size distribution according to the United States Department of Agriculture (USDA) soil classification and organic content, as well as data from the Basic Geological Map (BGM) at a scale of 1:100000, together with the information on the original parent material from which the soils originate. Field sampling (72 samples) and laboratory sample analysis were performed according to the USCS. The samples were collected at the same locations (50 samples) as the profiles which had been extracted during the de- velopment of BSM to enable a comparison of the two classification systems. The analysis did not confirm a clear statisti- cal connection between the USDA and USCS. The compatibility of BSM pedological units and low plasticity clays (CL) is clearly visible in all units, except for the units located on the alluvium. The presence of low plasticity clay (CL) and high plasticity clay (CH) has been confirmed in the stagnosols on the alluvium. By incorporating the geological basis into the spatial analysis, low plasticity clays were found to belong to the Quaternary source material, whereas high plasticity clays were formed on the parent substrate of Neogene age. Data analysis and cartographic representation of the results accord- ing to the Waterways Experiment Station (WES) Method of the cone index were obtained using fuzzy logic. The princi- ples of fuzzy logic were used at the boundaries of pedological units due to the inability to define clear boundaries or the cessation of a particular type of soil’s presence.

Qualidade da água de poços paralisados no município de Itapipoca, Ceará

O Estado do Ceará, devido à sua localização e clima, possui características bem específicas que afetam diretamente a disponibilidade hídrica na região. A elevada radiação solar incidente no Estado ressalta a necessidade de se realizar uma gestão integrada das águas superficiais e subterrâneas na região. Contudo, cadastros realizados pela Companhia de Pesquisa de Recursos Minerais (CPRM) apontam a existência de, pelo menos, 89 poços sem uso no município de Itapipoca/CE. Porém, não são apresentados dados sobre os motivos que levaram a sua inutilização. Assim, diante da necessidade ao acesso à água que predomina no semiárido, o presente trabalho apresenta uma pesquisa sobre os principais motivos que levam os poços da região à paralisação e um estudo sobre a qualidade da água dos mesmos, visando identificar suas possibilidades de reativação e uso. Para tanto, foram analisados cadastros de poços perfurados no Estado, visitas técnicas e análises laboratoriais de amostras coletadas em 8 poços. Durante o estudo foi identificado que os principais motivos para paralisação estão apresentados pela população estão relacionados a problemas de manutenção, baixa vazão, entupimento (acidental ou proposital) e qualidade da água. Por fim, foi possível concluir que apesar das amostras analisadas não atenderem aos padrões de potabilidade estabelecido pela Portaria de Consolidação n° 05/2017, o uso de tecnologias como dessalinização e alcalinização da água poderiam reativá-los.

Stripping traditionally productive Calcisols for tandir oven manufacturing in Diyarbakır, a semi-arid region in SE Turkey.

There is a close connection between human history and different purposes for which land is used, and various purposes can lead to the loss of productive agricultural lands. The increasing population in recent decades has particularly increased the pressure on agricultural lands. Despite the large number of land/soil misuse studies conducted during this period, land/soil loss is a continuing process. We thus seek to highlight the land/soil loss caused by the use of soil materials for the construction of tandır ovens in Diyarbakır region. The use of traditional tandır ovens is particularly widespread in eastern and northeastern rural Anatolia of Turkey, for baking bread. Because the soil material used in the production of this oven does not have any production standards, tandır oven producers extract their material from the nearest available lands that are mostly productive. Consequently, this study was conducted by collecting samples from soil materials used in the production of tandır ovens to determine their agricultural productivity. Satellite imagery from different dates was also used to detect the effects of inappropriate soil extraction. A number of interviews were conducted to obtain information on the type of soils extracted for production. Laboratory analyses of samples collected from the extracted areas revealed that soils' utilized for oven production physical and chemical properties, as well as their land characteristics (flatness, depth, and stoniness), were appropriate for crop production. Consequently, these results point to accelerated future soil degradation which will threat regions food production.

Analysis of the Levels of Alteration of Aquifers Caused by the Installation of Wind Farms on Dunes on the Coast of Ceará, Brazil

This research evaluated the levels of alteration of aquifers caused by installation of wind farms on dunes on the coast of Ceará, using the GOD and POSH methods of vulnerability, underground flow, and the application of multivariate analysis to subsidize the monitoring of groundwater quality in the area. There were three stages of field study: registering the wells and pollution sources, measuring the water levels, and groundwater sampling for laboratory analysis. The results obtained with the GOD method demonstrate the predominance of moderate- to high natural vulnerability of the aquifer to pollution in the areas close to the wind park in the district of Amarelas (Xavier and Ziu beach) and revealed high pollution loads according to the POSH method. The directional vectors of the underground flow are meaningful for Xavier Beach (high vulnerability), the center of Amarelas (moderate vulnerability), Tapuiu and Montevideo (low vulnerability). This indicated that the wind farm may have a potential impact on the lowering of groundwater in the area. From the multivariate analysis, it is evident that the groundwater characteristics are strongly related to the geological formation of the wells (Dunas and Barreiras), showing all samples within the Tolerable Maximum Value for human consumption for TDS, hardness, turbidity, and pH. It is vital to carry out preliminary studies of the aquifers underlying the areas where wind farms are to be installed, considering the levels of vulnerability and the risks of pollution and alteration of the water supply.

P6222Changes in main CVD risk factors in Finland 1992–2017

Abstract Background Systematic monitoring of cardiovascular disease (CVD) risk factors started in eastern Finland already in the 1970s as part of the North Karelia Project. Later on risk factor monitoring was extended to other parts of the country. Purpose In this study we report the trends of main CVD risk factors in Finland from 1992 to 2017. Methods Study population consists of a population-based random sample of 31 402 men and women aged 25–64 years who participated in the FINRISK Studies from 1992 to 2012, and in the FinHealth Study in 2017. Data collection was done every five years. Participation rate decreased from 76% in 1992 to 56% in 2017. Study protocol included self-reported questionnaire data on smoking and other health behavior, measurements of height, weight and blood pressure, and venous blood sample for laboratory analysis. Blood pressure was measured two times, and the average of the measurements was calculated, total serum cholesterol was analyzed using enzymatic method, and LDL cholesterol was calculated using Friedewald formula. Results Smoking prevalence, mean blood pressure and total and LDL cholesterol levels declined markedly during the 25 year follow up but BMI, waist circumference and prevalence of obesity increased (table). CVD risk factor change from 1992 to 2017 Risk factor Men 1992 Men 2017 p value Women 1992 Women 2017 p value Smoking (%) 36.7 20.6 <0.001 25.9 16.5 <0.001 SBP (mmHg) 136.6 131.2 <0.001 130.3 124.5 <0.001 DBP (mmHg) 82.7 81.6 <0.001 78.6 77.8 <0.001 Chol (mmol/L) 5.66 5.17 <0.001 5.42 5.18 <0.001 LDL chol (mmol/L) 3.54 3.16 <0.001 3.26 3.03 <0.001 BMI (kg/m2) 26.2 27.2 <0.001 25.1 26.4 <0.001 WC (cm) 92.8 96.1 <0.001 79.2 86.2 <0.001 Obesity (%) 15.7 23.2 <0.001 14.8 22.7 <0.001 Conclusions The levels of main traditional CVD risk factors have markedly decreased among the Finnish population during the last 25 years but in the same time, obesity has become a major public health challenge.

Characterizing P-Wave Velocity and Elastic Properties of Sedimentary Rocks for Foundation of Building

The aim of this paper is to develop empirical models based on laboratory experimental works using a number of rock samples using seismic velocity parameters and deformation properties. Furthermore, it is very important to express the relationship between elastic properties and seismic velocity of tropical sedimentary rocks which can be used for construction of foundation building. Ultrasonic pulse velocity test (UPV) is used worldwide to measure ultrasonic wave velocity which able to penetrate through intact rock and the wave travel time is depending on the particle arrangement of rock microstructure. Elastic properties of rock such as Young modulus, shear modulus and bulk modulus can be determined by conducting uniaxial compressive strength test (UCS) with deformation measurement. The results between the P-wave velocity were correlated and regression equations were established to present the correlation between them. Regression analysis (R2) shows that the correlation values of P-wave and Young modulus, shear modulus and bulk modulus at 0.63, 0.61 and 0.60, respectively. It can be concluded that from the relationship of P-wave and elastic properties parameters, the result of allowable soil bearing pressure can be used for design foundation building and the laboratory analysis of samples is used to predict P-wave velocity.

Distribution and characteristics of microplastics in the sediments of Poyang Lake, China.

Microplastics are considered to be a widespread environmental contaminant, posing a serious threat to the aquatic environment. We addressed this issue based on field observations and laboratory analysis of samples from Poyang Lake. We collected sediment samples from 10 sites across Poyang Lake during 2017. Data were analyzed by one-way analysis of variance (ANOVA). Results showed that the abundance of microplastics ranged from 11 to 3,153 items/kg dw in the sediment samples. Except at Nanjishan, the amount of microplastics in different periods decreased in the order: December > April > July. Microplastics with a size <1 mm were the most abundant fraction in sediments, reaching over 50%. Observations under microscope revealed four types of microplastics in Poyang Lake: fragments, films, foams and fibers. Fragments were more common in sediments. Microplastics have complex surface topography, typically including rough surfaces, porous structures, cracks and extensive damage. Energy dispersive X-ray analysis indicated that most microplastics contained Si, Na, Ca, Cl and Al. Overall, the results provided strong evidence of high levels of microplastics in Poyang Lake, suggested that the microplastics pollution status in Poyang Lake should continue to be monitored.

Fabrication of a Cu(II)-Selective Electrode in the Polyvinyl Chloride Matrix Utilizing Mechanochemically Synthesized Rhodamine 6g as an Ionophore.

A Cu(II)-selective electrode has been fabricated by utilizing a mechanochemically synthesized copper-specific ionophore “L” embedded in a poly(vinyl chloride) membrane. 2-Nitrophenyloctylether and sodium tetraphenylborate have been used as a plasticizer and as a solvent mediator, respectively, and found to be enhancing the sensitivity of the fabricated ion-selective electrode (ISE). A range of membranes (S1–S7) with varying compositions were casted and investigated in ISE. Results revealed an excellent Nernstian response of 29.38 ± 0.55 mV/dec for the ISE S6. The fabricated ISE operates well in the pH window 4.0–7.5, and the limit of detection was found to be 5 μM (0.3 ppm). Quick response time (15 s), long shelf-life, and selectivity (on the order of 10–4 and 10–5) over a number of interfering cations enabled S6 promising for real off laboratory sample analysis and can be employed to detect copper ion in various industrial as well as biological and environmental samples. To demonstrate the practical application of these ISE, the Cu concentration in the digested printed circuit board has been estimated using the standard calibration plot. The fabricated ISE has been regenerated through extracting copper by chelating with ethylenediaminetetraacetic acid.

Simple and Economical Analytical Voltammetry in 15 μL Volumes: Paracetamol Voltammetry in Blood Serum as a Working Example.

Reported is a three-electrode mini-cell for voltammetry in 15 μL solutions. The key device component is a rolled platinum foil of an inverted omega-shaped cross section, which functions as both the electrolyte container and the counter-electrode. The analytical assembly was completed with properly sized working and reference electrodes in the two terminals of the quasi-tubular Pt trough. Its applicability in electrochemical assays of 15 μL solutions was verified by redox mediator voltammetry at graphite and noble metal sensors and by trace lead stripping voltammetry. Real sample analysis was adequate for drug detection in a volunteer's blood, drawn before and 1 or 4 h after ingestion of paracetamol. In line with its known pharmacokinetics, lack of drug as well as drug presence and clearance were proven correctly in the three samples. The mini-cell here is easy to assemble and operate, indefinitely reusable, and offers valuable economy in chemical usage and minimal waste. This is primarily a versatile device for electrochemical laboratory analysis of samples that are available only in small quantities, and cost-effective quantitative screens for expensive high-molecular-weight compounds, products of microsynthesis, physiological microdialysis collections, and finger-prick blood sampling are seen as feasible targets.

Research of Heavy Metals Pollution Soil Risk Evaluation by Means of Engineering in Gold Mining Area, Tongguan, China

As the core technology of soil heavy metal remediation and management in Tongguan gold mining area, only the objective and comprehensive evaluation of its governance effect can we promote this technology in Tongguan gold mining area and other similar areas Applications provide solid and reliable data support and scientific basis. In this study, samples were set up in the project area of Tongguan gold mining area. Primary data of the control area were obtained through sample collection and laboratory sample analysis. Soil samples of Tongguan gold mine project area were analyzed by single pollution index method and Nemero integrated pollution index The results showed that all kinds of metal elements in tillage soil have reached the level of cleanliness and the soil quality belongs to the first grade safety status, which provides the data support and scientific basis for the popularization and application of the project.

Continuous Infusion of Low-Dose Iohexol Measures Changing Glomerular Filtration Rate in Critically Ill Patients.

Measurement of changing glomerular filtration rate in acute kidney injury remains problematic. We have previously used a continuous infusion of low-dose Iohexol to measure glomerular filtration rate in stable subjects and postulate that changes greater than 10.3% in critically ill patients indicate acute kidney injury. Our objective is to explore the extent to which continuous infusion of low-dose Iohexol can be a measure of changing glomerular filtration rate during acute kidney injury. Clinical observational exploratory study. Adult ICU. Three patient groups were recruited: nephrectomy group: predictable onset of acute kidney injury and outcome (n = 10); surgery group: predictable onset of acute kidney injury, unpredictable outcome (n = 11); and acute kidney injury group: unpredictable onset of acute kidney injury and outcome (n = 13). Continuous infusion of low-dose Iohexol was administered for 24-80 hours. Plasma (ClP) and renal (ClR) Iohexol clearances were measured at timed intervals. Kidney Disease: Improved Global Outcomes acute kidney injury criteria were fulfilled in 22 patients (nephrectomy = 5, surgery = 4, and acute kidney injury = 13); continuous infusion of low-dose Iohexol demonstrated acute kidney injury in 29 patients (nephrectomy = 10, surgery = 8, acute kidney injury = 11). Dynamic changes in glomerular filtration rate were tracked in all patients. In the nephrectomy group, ClR decreased by an expected 50% (50.8% ± 11.0%). Agreement between ClP and ClR improved with increasing duration of infusion: bias of ClP versus ClR at 48 hours was -0.1 ± 3.6 mL/min/1.73 m (limits of agreement: -7.2 to 7.1 mL/min/1.73 m). Coefficient of variation of laboratory sample analysis was 2.4%. Continuous infusion of low-dose Iohexol is accurate and precise when measuring glomerular filtration rate and tracks changes in patients with differing risks of acute kidney injury. Continuous infusion of low-dose Iohexol may provide a useful standard against which to test novel biomarkers for the diagnosis of acute kidney injury.

The Monitoring of selected sources in the administration of the Forests of Brno

The article concerns the monitoring of selected sources (monitored a total of 10 springs, presented the results of 5 springs) administered by the Forests of the city of Brno in the northern district of Brno-county, describing their current state, including the evaluation of selected water quality parameters. The basis of the study was to measure basic water quality parameters (water temperature, pH, oxygen and measuring the rate of flow of water in springs) and sampling for laboratory analysis. The values obtained were tabulated and graphically evaluated and compared with values in accordance with Decree no. 252/2004 Coll., which lay down the hygienic requirements for drinking water. Based on the measured values charts and graphs were compiled, and the water quality of the individual strands were assessed. The overall condition of wells and their surroundings is described in detail and assessed.

Quality Indexes and Feasibility Analysis of Traditional Dried Anchovy From Buru Island

Dried anchovy is a prominent fishery product in Buru Island Maluku. It is produce traditionally in villages Batuboi and Siahoni at Kayeli bay. Drying process was done in open air under the sun directly during two days to produce dried anchovy with a prospective marketable. This preliminary research was aimed to investigated the quality indexes and business feasibility of dried anchovy produced by processor comunity. The quality index was found by laboratory analysis of sample dried anchovy referring to Indonesian National Standard. The data for feasibility analysis was found by interview and by using quesioner list. The average Quality indexes of dried anchovy as follows: Water 14.22 grams percent; Protein 55.68 grams percent; Fat 2.29 grams percent; Ash 9.02 grams percent; Total Bacteri (TPC) 3,5 × 102-; organoleptic value 7.79; E. coli, Salmonella and Mold were unidentified. Total cost of dried anchovy production is 37,050,720 Rupiahs/year with the income was 224,000,000 Rupiahs/year. Total profit is 217,824,880 Rupiahs/year and the Revenue Cost ratio was 6.05. Dried anchovy from Buru Island has a good quality and also has a good business feasibility.

Yield and sward composition responses of a native grassland to compost application

A major part of the animal products are based on the grasslands, due to the fact that the grassland ecosystems can be found all over the globe. In places where economical and successful crop production cannot be realized, the grassland based animal husbandry can be an efficient way of food production. In addition these ecosystems have an important role in carbon sequestration, and with their rich flora – and the fauna connected to it – in conservation of biodiversity. The protection of nature, and the sustainable agriculture is getting more and more attention in the European Union, but looking at the consumers’ needs, the production of healthy food cannot be neglected either. Because of these facts, the effects of two specific composts - which are officially authorized in organic farming, in Agri-environment Schemes and Natura 2000 programs – on grass yields and sward compositions were investigated in a field trial. The investigation took place in Hungary, on a natural grassland based on solonetz soil. The first type of compost was a natural one (N) without any additional material and the other one was enriched in phosphorus (E). Both was produced by the research institute, made of sheep manure. Three rates of compost (10 t ha-1, 20 t ha-1,30 t ha-1) were tested on 3 m×10 m experimental plots. Every treatments had four replications and both type of compost had four-four control plots too, this way 32 experimental plots were included in the investigations. The yield of the pasture was harvested two-times (in May and in September) and before cutting the plots measurements on botanical compositions were made. Samples for laboratory analysis were also taken. Dry matter yield and crude protein content was measured in laboratory and with the received data the yield per unit area was calculated. Based on the research results we can say that the application of compost in any dose inflicts higher dry material and crude protein yield. The changes were partly due to some positive changes in sward composition, because of the better nutrient conditions. The research results indicate, that use of organic compost can be an efficient way to increase grass yields in a sustainable way.

Biodiversity indexes in relation to soil properties in upland fir forests (Abietetum albae)

Abstract The aim of this study was to present the relationship between soil properties and biodiversity indexes in upland fir (Abies alba) forest associations (Abietetum albae). Our study was conducted in six areas representing the growth conditions of upland fir forests and the research plots were located in the Roztoczański and Świętokrzyski National Parks as well as Przedbórz, Radomsko, Piotrków and Janów lubelski Forest District. on every plot, the topography was described, soil cores were examined and samples for laboratory analysis were taken. the following characteristics were determined for the soil samples: ph, c, n, ca, Mg, na and K content, particle size, exchangeable acidity, aluminum content and hydrolytic acidity. additionally, enzyme activity in the soil samples (urease and dehydrogenase) was measured. in each test area, the stand characteristics were measured (diameter at breast height and height), floristic characteristics were described and the biodiversity indexes (Shannon, Simpson and Margalef indexes) were calculated. Different soil types (gleysols, Brunic arenosols, gleyic Podzols and hyperdistric cambisols) were recorded for the investigated forest stands and the soils were categorized according to soil texture, c content, enzyme activity and different humus types (moder-mor, moder, moder-mull). the upland mixed coniferous forest sites were characterized by lower biodiversity indexes (2.6 shannon index; 0.72 simpson index; 4.9 Margalef index) while the upland mixed broadleaf forest sites showed higher indexes (3.3 Shannon index; 0.87 Simpson index; 9.4 Margalef index). The site index obtained for the fir stands confirmed these results.

DEVELOPMENT AND VALIDATION OF UV SPECTROSCOPIC METHODS FOR SIMULTANEOUS ESTIMATION OF SALBUTAMOL SULPHATE AND DOXOPHYLLINE IN COMBINED SOLID DOSAGE FORM

Objective: Salbutamol sulphate (SBS) and doxophylline (DOX) was used for the treatment of asthma and bronchitis. In the present study, two simple, accurate, precise, reproducible and economical UV-spectroscopic methods (A and B) for simultaneous estimation of SBS and DOX in tablet dosage form have been developed.Methods: In the present study the simultaneous estimation of SBS and DOX was carried out by two methods. Method A employs solving of simultaneous equations based on the measurement of absorbance at two wavelengths, 272 nm and 276 nm which are the 𝜆max values of SBS and DOX respectively in phosphate buffer (pH 7.4). Method B is based on the principle of Q-Analysis where in, absorbance was measured at 225 nm (iso-absorptive point, 𝜆1) and 276 nm (𝜆max of DOX, 𝜆2) in phosphate buffer (pH 7.4).Results: Both SBS and DOX shows linearity at all the selected wavelengths and obeys beer’s law in the concentration range of between 0.2-1.6𝜇g/ml and 0.1-3.5μg/ml at 276 nm; 0.2-1.6 µg/ml and 0.1-4.5 µg/ml at 272 nm and 0.2-2.0µg/ml and 0.2-3.5μg/ml at iso-absorptive point 225 nm. Recovery studies for SBS and DOX were performed and the percentage recovery for both the drugs was obtained in the range of 97.45-98.63% (Method A) and 97.49–98.87 % (Method B) confirming the accuracy of the proposed method.Conclusion: Both the methods showed good reproducibility and recovery with % RSD less than 2. Statistical validation of the data shows that the proposed methods can be successfully applied for the routine analysis of drugs in commercial tablets. Hence, it could be used in the analysis of laboratory samples and marketed formulations containing these two drugs in combined dosage form without the interference of common excipients.

Changes of soil organic and inorganic carbon in relation to grassland degradation in Northern Tibet

AbstractThe effect of livestock grazing on grassland degradation and the resulting impact on soil carbon concentration is an important factor in carbon estimation. We addressed this issue using field observations and laboratory analysis of samples from Tibetan grassland. Based on the field measurements, we investigated the soil organic carbon (SOC) and soil inorganic carbon (SIC) under two contrasting degradation states: lightly or non‐degraded grasslands (LDG) and heavily degraded grasslands (HDG). We assessed their relationships with environmental factors using data collected from 99 sites across Northern Tibet during 2011–2012. Data were analyzed using a linear mixed‐effects model and one‐way ANOVA. The results showed that: (1) SOC concentration decreased and SIC concentration increased following grassland degradation, especially at soil depths in the range of 0–10 cm (P &lt; 0.05); (2) the major environmental factors affecting SOC and SIC were soil pH and plant biomass; (3) spatially, the SOC density increased with the mean annual temperature and mean annual precipitation, whereas SIC exhibited the opposite trend; (4) the SOC density increased at first and then decreased with increasing grazing intensity, with an opposite trend in SIC; and (5) soil carbon storage in this region was 0.14 Pg smaller in the HDG than in the LDG. This study suggests that grassland degradation can significantly affect the vertical distribution and storage of SOC and SIC. The carbon sequestration capacity of the top 100 cm of soil in Northern Tibet was estimated as 0.14 Pg.