High Standard Deviation Research Articles

Investigating Rainfall Patterns in the Hubei Province, China and Northern Italy During the Covid-19 Lockdowns

In the spring of 2020, many countries enacted strict lockdowns to contain the spread of the 2019 coronavirus disease (COVID-19), resulting in a sharp observed decrease in regional atmospheric pollutant concentrations, such as NOx and aerosols in early 2020. Atmospheric composition can influence cloud properties and might have a significant effect on the initiation of precipitation. This study investigated changes in precipitation patterns during COVID-19 lockdowns and compared them to patterns observed during the previous 19 years (2001 through 2019) across two regions of interest, the Hubei province in China and Northern Italy using a satellite-based precipitation dataset. Results indicated that overall rainfall averages were higher in the spring of 2020 with respect to their corresponding climatological means, with higher standard deviations especially in the more urbanized regions like Wuhan, China and Milan, Italy. Precipitation rates observed during the Spring of 2020 tend to fall outside of the climatological 25–75th percentile bounds. Similarly, the number of rainy pixels was in several cases in Spring 2020 higher than the climatological 75th percentile and sometimes even higher than the 95th one. These anomalies may be due to natural variations and may not be caused directly by the reduction in atmospheric pollutant concentrations. Nevertheless, our analysis proved that precipitation patterns during the lockdowns were on the extreme tails of the precipitation climatological distributions for both regions of interest. Lastly, decorrelation lags and distances in Northern Italy remained similar to their corresponding climatological values, whereas in the Hubei province some differences were observed, with the Spring 2020 spatial correlation variogram almost overlapping the climatological 5th percentile and with a decorrelation distance shorter than the climatological value.

Clinical parameters influencing the results of anterior rhinomanometry in children.

Nasal obstruction is a frequent symptom in both adults and children and it is a common reason to see an otorhinolaryngologist. Endoscopy of the nasal cavity and the epipharyngeal space along with anterior rhinomanometry is regarded the gold standard since many years to estimate the severity of nasal obstruction in the particular patient. Endoscopy shows anatomical reasons for an obstruction, whereas the nasal flow volume and nasal resistance can be determined using anterior rhinomanometry. Currently, there are only few data available for rhinomanometry results in children. The purpose of the present study was to evaluate the application of this technique in the pediatric population for objective evaluation of nasal flow. Whether it achieves reproducible results and which clinical parameters have some influence on the results were studied. 427 children (average age of 8.5years, range 7months through 17years) who were admitted to evaluate nasal patency or for allergy testing were examined. After clinical examination and endoscopy of the nasal cavity and epipharyngeal space, anterior rhinomanometry was performed before and after application of decongestant nose drops separately for each nose side in 334 children. The nasal flow with a pressure of 150 Pasc was measured and served for statistical evaluation. Flow values were correlated to clinical and endoscopic parameters along with results of allergy tests (prick tests). Reproducible rhinomanometric measurements were possible in children age 3years and older. However, the standard deviation and variation of measurements were significant in this cohort of patients. Statistically highest significant correlations were found between flow measurements and body height along with the age of the children (p < 0.01) and status following adenoidectomy (p < 0.05). No statistically significant correlations were found between rhinomanometry and results of prick tests. The study demonstrates that rhinomanometry can be applied in the pediatric population for objective evaluation of nasal obstruction and for determining the effects of decongestant nose drops. The highest correlation was found between nasal flow and children's body height, children's age and status following adenoidectomy. The correlation between nasal flow and clinically/endoscopically determined degree of nasal obstruction was lower. However, definition of normal flow values for particular age groups is challenging since the results showed high variation and standard deviation. Yet with regard to individual patient, the technique achieves reliable results in nasal provocation tests, which are widely used for allergy testing in children. When performed in children it should always be considered that there are age-specific requirements for the examination and interpretation of results in this patient cohort.

Evaluating strategies for monetizing natural gas liquids from processing plants – Liquid fuels versus petrochemicals

The processing of natural gas resources is a critical step for monetizing them. Its evaluation should deal with the volatility of prices of raw gas and natural gas liquids, the processing technology and the composition of the raw gas. This study combines different approaches – process engineering, probabilistic discounted cash flow (DCF), and market failure analysis – to evaluate the technical aspects, financial results and market barriers of natural gas processing. Two productive strategies are compared: fuels or petrochemicals. Brazil is used as a case study, since the country experienced a ramping production of associated rich gas from pre-salt basins and lacks the required gas processing capacity. Findings indicate that the processing plant designed with turboexpander was able to produce the required scale for the fuel and the petrochemical markets. The Petrochemical Strategy reached a higher average net present value (US$ 2448 millions) compared to the Fuel Strategy (US$ 2006 millions) in a 30-years DCF analysis, at a higher standard deviation, however. This highlights the importance of performing the stochastic NPV to deal with price volatilities. The Petrochemical Strategy is also challenged by market failures found in Brazil, while the Fuel Strategy has social and infrastructure advantages in a stablished domestic market.

Neighborhood Disadvantage Is Associated with Lower Quality Sleep and More Variability in Sleep Duration among Urban Adolescents.

Differential social and contextual environments may contribute to adolescent sleep disparities, yet most prior studies are limited to self-reported sleep data and have not been conducted at a national level, limiting the variation in neighborhood contexts. This study examined the association between neighborhood disadvantage and objective measures of adolescent sleep. A racially and geographically diverse sample of American adolescents (N = 682) wore wrist-worn accelerometers, "actigraphs," for ≥ 5 nights. Neighborhood disadvantage was calculated using a standardized index of neighborhood characteristics (proportion of female-headed households, public assistance recipients, households in poverty, adults without high school degrees, and unemployed). Adolescents in more disadvantaged neighborhoods spent more time awake after falling asleep (4.0min/night, p < .05), a greater percentage of nighttime sleep intervals awake (1%, p < .01), and had less consistent sleep duration (11.6% higher standard deviation, p < .05). Sleep duration and timing did not differ across neighborhood groups. These findings demonstrate that adolescents who live in more disadvantaged neighborhoods have lower quality, less consistent sleep.

Characterization of volcanoclastic succession in South West Sardinia: In situ vs. laboratory assessment of compressional wave velocity

Non-destructive ultrasonic analyses for the measure of compressional wave velocity (VP) can represent a non-invasive technique to characterize different lithologies and to set data from geophysical logs. This study shows a comparison between in situ and laboratory measurement of VP and its correlation with density, porosity and water content with reference to three geologic formations (i.e. the Monte Crobu, Nuraxi and Paringianu rhyolites), with the final aim to obtain essential data to support the experimental campaigns on the Sotacarbo Fault Lab, a research facility to study CO2 leakage in southwest Sardinia. The considered formations are characterized by a significant heterogeneity, highlighted by the relative wide dispersion of the experimental data (characterized by a high relative standard deviation). In any case, as expected, a direct and slightly positive correlation between VP and bulk density has been found, whereas an opposite trend has been found for the correlations between VP and both porosity and water content. A significant impact on VP value can be ascribed to the pore structure of the considered lithotypes: if pores are non-interconnected, sample saturation in water bath does not involve any significant increasing of VP. And water content can even involve a reduction of P-wave velocity in specific conditions that can reduce the capacity to absorb water. The whole study indicates a mild correlation between in situ and laboratory measures of compressional wave velocity.

Adoption Rates of NERICA Innovation among Rice Farmers in Northern Ghana

Adoption rates of the New Rice for Africa (NERICA) have been generally low across Africa, indicating that the innovation has not been well accepted on the African continent, including Ghana. The adoption rates of the innovation were determined in Northern Ghana to ascertain the extent to which farmers have accepted to grow the ‘magic’ crop in curbing food insecurity, poverty, unemployment, and rice importation. However, the adoption rates so determined were too low, due to incomplete diffusion. The current paper aimed at determining the rates of adoption of NERICA in Northern Ghana from 2015 to 2018, to verify the findings and predictions of previous researchers. Simple random sampling technique was accordingly used to obtain quantitative and qualitative data from 346 rice farmers. The data were analyzed qualitatively and quantitatively using logistic regression as well as descriptive statistics. The study revealed a low average adoption rate of 25% with a high standard deviation of 44.03%, indicating an uneven spread out of the adoption rates over the period under study. However, the specific adoption rates of the innovation were 91.04%, 3.18%, 2.89% and 2.89% for 2015, 2016, 2017 and 2018 farming seasons respectively, confirming that the rates rose to 91% but fell drastically in subsequent years as predicted by previous researchers. Farmers' educational level, perception of NERICA, family size and rice farming significantly affected adoption of NERICA. The persistent low adoption rates showed that the innovation was unsuccessful in the study area. The Ministry of Food and Agriculture should therefore intensify her innovation dissemination/diffusion campaigns in the study area to revamp its adoption; by providing ready jobs to the youth and market for the commodity through the flagship programs, Planting for Food and Jobs, and the National Food Buffer Stock Company.

Modelling and experimental validation of polarization behavior of airbreathing microfluidic fuel cell using some common fuels: Methanol, ethanol and sodium borohydride

• MFC was fabricated with the prepared anode and airbreathing cathode. • A mathematical model is developed by considering various losses at anode and cathode. • The performance of the cell was assessed by evaluating polarization characteristics. • The predictions of the model-equations are validated to the experimental observations. Airbreathing microfluidic fuel cell (MFC) is emerging as the potential energy source for prospective use in glucose sensors, pacemakers, healthcare diagnostics, mobile phones, and DNA analysis devices, etc. A mathematical model of airbreathing MFC can aid in the explanation of a system as well as the prediction of behavior. In this line of work, the mathematical model for an airbreathing MFC was developed. Moreover, various losses such as activation, ohmic, and concentration overpotentials at anode and cathode were taking into account in the development of mathematical model. This developed model was validated with experimental data on current density vs. cell voltage characteristics at different fuel concentrations of 0.25 M to 1 M (CH 3 OH, C 2 H 5 OH) and 0.05 M to 0.3 M (NaBH 4 ) along with cell temperatures (33 °C, 50 °C and 65 °C). For these experiments, the electrocatalysts used to prepare the anodes were Platinum-Ruthenium (Pt-Ru) (30%:15% by wt.)/high surface area carbon (C HSA ) (fuel: CH 3 OH, C 2 H 5 OH), and Platinum (40% by wt.)/C HSA (fuel: NaBH 4 ). The cathodes were prepared using Pt (40% by wt.)/C HSA . The model's findings are in agreement with the experimental results well. Model prediction equation fairly reflected the influence of process variables such as fuel/electrolyte concentration and cell temperature on the prediction. The standard deviation values are found very low (0.02 to 0.082), indicating that developed mathematical model can be utilized in development of devices for industrial along with lab based applications. A high standard deviation, on the other hand, implies that the values are spread out across a higher range.

Mechanical characterization of 3D-printed silicone/epoxy hybrids

A new family of materials made of chemically compatible silicone/epoxy hybrids was recently reported. By tuning the silicone/epoxy ratios, the elasticity of the hybrid could be finely tuned over five orders of magnitude. Processable by direct ink writing (DIW), an extrusion-based additive manufacturing technology, these materials displayed high interfacial toughness between different phases. In this study, the impact of two key parameters on the mechanical characterization of these hybrids was studied. First, the impact of reducing the tensile test specimen by a factor 3 from established ASTM standards was analyzed. It was found that reducing the sample dimensions does not significantly alter the mechanical properties, even though higher standard deviations were observed in the range of 5 to 15%, in particular for stiffer samples. Second, the impact of printing orientation was studied by comparing samples printed longitudinally and transversally to the tensile direction. Longitudinally printed samples exhibited higher stiffness properties of about 15% to 35% than transversally printed specimens (higher elastic modulus, lower elongation at break), while values between longitudinally printed and cast samples with same dimensions were comparable. These results show the possibility to reduce the sample dimensions when savings in processing time, costs, or materials are required, while processing materials by DIW impacts the mechanical properties.

Grain size variation in the swash zone of Lhoong Beach, Aceh Besar

The spatio-temporal texture characteristics are key parameters for understanding the dynamics of the sedimentary environment. This study was conducted to determine the sediment characteristics in swash zone of Lhoong Beach, Aceh Besar Regency. The analysis emphasizes the seasonal variation of sediment mean grain size (MGS) based on vertical stratification. Sediment samples were taken during November 2018, January 2019 and March 2019, from 3 stations. Samples from station 3 had the coarsest grain characteristics, where the highest MGS value at station 3 was recorded in the mid-layer (5-10 cm) in November. The grain size was found to vary with changing seasons and the depth of the sediment layer. Based on depth stratification, the highest standard deviation was obtained by the mid-layer (5-10 cm); while by period, the highest standard deviation of the MGS value was generated during November.

INTERDISCIPLINARY EDUCATION THROUGH THE DEVELOPMENT OF A COST-EFFECTIVE PHOTOMETRIC pH METER SENSOR USING NATURAL PIGMENTS

There is a trend of development of analytical methodologies and technologies that allow in situ analysis, producing accurate information in real time, at low cost, using homemade experiments and devices to increase interest in scientific knowledge with a constructive approach in an interdisciplinary perspective in Chemistry Education. In this context, a photometric-chemometric method of analysis was developed to measure the pH of solutions using easily accessible and low-cost material based on the use of natural pigments found in red cabbage (Brassica oleracea L.). Calibrations and determinations were performed by RGB measurements of pigment coloration in solution at different pH values using the free app Photometrix, converted to HSV, YCbCr and YUV color spaces and processed by Partial Least Squares regression (PLS). The best PLS model found was HSV with mean central scale obtained pH measurements with RMSEP 0.98, R2 0.97 and bias close to zero. In addition, experimental data were statistically validated. Analyzes of predicted pH from three independents experiments revealed high recoveries (95-103%) and low relative standard deviations. Thus, the PhotoMetrix app was viable for colorimetric pH determinations using the low-cost photometric pH meter sensor and a smartphone, improving accessibility and applicability in Chemistry Education.

Prematür Overyan Yetmezlikli Ratlarda Yaş Kupa Terapisinin Anksiyete ve Tiyol/Disülfit Homeostazı Üzerine Etkileri: Deneysel Bir Çalışma

Objective: The effect of wet cupping therapy on anxiety and thiol/disulfide homeostasis was evaluated in rats with premature ovarian failure (POF) induced by cyclophosphamide (CYC). Material and Methods: Twenty four Wistar Albino female rats were divided into control (n=6), POF (n=6), wet cupping (n=6), POF+wet cupping (n=6) groups. CYC at a dose of 200 mg/kg was injected intraperitoneally to POF and POF+wet cupping groups. One week later, wet cupping therapy was applied to wet cupping and POF+wet cupping groups for 5 minutes. The next day, Open Field Test and Elevated Plus Maze Test were applied to all experimental groups to evaluate anxiety. After sacrification, to assess pattern formation, endometrial thickness and ovarian reserve were measured with hematoxylin-eosin staining. Thiol/disulfide homeostasis and erythrocyte oxidized-reduced glutathione levels were measured in serum to measure oxidative stress. Results: Although there was no statistical significance, it was observed that anxiety decreased in POF+wet cupping compared to POF group. There was no change in thiol-disulfide values in POF+wet cupping compared to POF group (p>0.05). Conclusion: Wet cupping therapy did not reduce anxiety in the experimental POF model and did not shift the balance to positive in thiol/disulfide homeostasis in favor of thiols. However, the obtained graphics, numerical data and high standard deviation suggest that meaningful data could be obtained with more subjects.

The effect of ore heterogeneity on the net value of a grinding/flotation product

Ore heterogeneity (e.g., head grade, hardness, density and lithology) represents an important preoccupation for any given mine. The actual consequence of this variability is not always clear on the bottom line, especially when the average value remains constant over time. This paper examines the effect of random variations of two feed particle characteristics, namely the size index and grindability, on the net value of a grinding/flotation plant product. The simulated plant consists of rougher flotation cells processing the ore ground by a 2-stage semi-autogenous/ball mill circuit. Normal Gaussian distributions model the centered heterogeneity over time for three level of standard deviations (low, moderate and high) generating 32 possible scenarios. The high variability case reduces the product net value compared to the low variability one, equivalent to 1.5 M$/year loss. The additional revenues come from the ability to process more ore on average, while achieving the desired product size index in narrow variability situations. Conversely, high standard deviations lead to a slightly coarser ground product. The proposed simulation setting provides a quantitative basis to assess the financial benefits of regulatory control, and ore blending systems.

Analytical Method Development and Validation for Estimation of Bedaquiline (BDQ) Using RP-HPLC

The United States Food and Drug Administration (USFDA) approved bedaquiline (BDQ) in 2012 for the treatment of drug-resistant tuberculosis, which has become a serious global issue. For the measurement of bedaquiline in bulk medication, a reversed-phase high performance liquid chromatography (RP-HPLC) approach was devised and validated. The separation was obtained using a 10mM Ammonium acetate: methanol in the ratio 15:85 v/v (pH adjusted to 4.5 with OPA) as mobile phase at a flow rate of 1.0 ml/min on a Thermo C18 analytical column (250mm4.6 mm i.d.,5.0µ). A UV detector with a 232mm focal length was used for detection. The entire chromatographic analysis time per sample was around 5.0 minutes, with emtricitabine eluting at roughly 3.225minutes retention time. The accuracy, precision, specificity, linearity, and sensitivity of the approach were all tested. Validation studies have shown that this HPLC approach is simple, specific, quick, dependable, and repeatable. The standard curve was linear over the concentration range of 5-25μg/ml with r2 close to one (0.999). Bedaquiline had a limit of detection (LOD) of 0.3525μg/ml and a limit of quantitation (LOQ) of 0.95 25μg/ml, respectively. The suggested method's high recovery and low relative standard deviation show its usefulness for determining bedaquiline in pharmaceutical formulations.

Maternal early-pregnancy ferritin and offspring neurodevelopment: A prospective cohort study from gestation to school age.

BackgroundIron plays a role in many key processes in the developing brain. During pregnancy, iron supplementation is widely recommended to prevent and treat iron deficiency; however, the prevalence of iron deficiency and the risk of iron overload vary greatly between populations. Evidence on the role of high levels of maternal ferritin, a storage iron marker during pregnancy in relation to offspring neurodevelopment is lacking.ObjectiveOur main objective was to examine if maternal ferritin levels during pregnancy are associated with child cognitive and motor abilities.MethodsWe included Dutch mother‐child dyads from the prospective population‐based Generation R Study, born in 2002–2006. We compared children whose mothers had high (standard deviation score >+1) or low (standard deviation score <−1) early‐pregnancy ferritin to children whose mothers had intermediate ferritin (reference group) using linear regression. Children underwent non‐verbal intelligence and language tests at 4–9 years (cognitive abilities), finger‐tapping and balancing tests at 8–12 years (motor abilities), and structural magnetic resonance imaging at 8–12 years (brain morphology). Covariates were child age, sex, maternal intelligence quotient estimate, age, body‐mass‐index, education, parity, smoking and alcohol use.ResultsOf the 2479 mother‐child dyads with data on maternal ferritin and at least one child neurodevelopmental outcome, 387 mothers had low (mean = 20.6 µg/L), 1700 intermediate (mean = 64.6 µg/L) and 392 high (mean = 170.3 µg/L) early‐pregnancy ferritin. High maternal ferritin was associated with 2.54 points (95% confidence interval ‐4.16, ‐0.92) lower child intelligence quotient and 16.02 cm3 (95% confidence interval ‐30.57, ‐1.48) smaller brain volume. Results remained similar after excluding mothers with high C‐reactive protein. Low maternal ferritin was not associated with child cognitive abilities. Maternal ferritin was unrelated to child motor outcomes.ConclusionHigh maternal ferritin during pregnancy was associated with poorer child cognitive abilities and smaller brain volume. Maternal iron status during pregnancy may be associated with offspring neurodevelopment.

Penentuan Titik IGS sebagai Titik Ikat dalam Pengolahan Data GNSS untuk Studi Geodinamika di Pulau Sumatra

Geodynamic studies on the Sumatra island generally use GNSS data. GNSS data processing using the differential method by using the IGS point as a tie point. This study aims to determine good IGS point in processing GNSS data for geodynamic studies on the Sumatra island. The data used are GNSS data from 3 SuGAr points and 20 IGS points in 2019 with DOY 061, 062, and 063. 211 GNSS data processing is carried out using different IGS points. The number of tie points used are 18, 19, and 20 IGS points. Determination of a good IGS point is based on the results of the standard deviation. The factors that cause the standard deviation value are the quality of the IGS point, distance, and temperature value. The processing results with 18 IGS points are better than 20 IGS points when using poor IGS points. The processing quality at the SuGAr point on the southern part of Sumatra Island (TJKG point) is the best compared to the other two SuGAr points. IGS points that are bad for geodynamic studies are XMIS and PBRI points because of the high standard deviation values for close distances. Good IGS points with low standard deviation values are COCO, DGAR, and LHAZ points. The low temperature value at the LHAZ point is thought to be the cause of the low standard deviation value. Â Keywords : GNSS, Standard Deviation, Precision, IGS, Differential

Revisiting the volatility of bitcoin with approximate entropy

Two distinct and non-redundant understandings of volatility, as deviation from consistency, exist for a time-series: (1) exhibiting high standard deviation and, closer to the dictionary definition of the term, (2) appearing highly irregular and unpredictable. We find that Bitcoin is a prime example of an asset for which the two concepts of volatility diverge. We show that, historically, Bitcoin combines high Standard Deviation and low Approximate Entropy, relative to Gold and S&P 500. Moreover, subsample analysis for different time-scales (daily, weekly, monthly) shows that lower sampling frequencies drastically reduce the Kurtosis of the distribution of log-returns of Bitcoin. The opposite effect is observed for Gold and S&P 500. These properties suggest that, contrary to the volatility of the two traditional assets, Bitcoin’s high volatility is essentially an intra-day phenomenon that is strongly attenuated for a weekly or monthly time-preference.

Profiling of Peak Intensity and Standard Deviation of Metabolites in Industrially Important Red Seaweed Gracilaria dura (Rhodophyta) by 1H NMR Spectra for Benchmarking

Mapping of regulatory components of cellular functioning by 1H NMR metabolomics has recently paved the way to study biochemical pathways in plants. Despite the enormous complexity and heterogeneity of the metabolites, the estimation of molar concentration allows for their direct quantification without calibration for individual compounds. 1H NMR spectra of near-native extracts were recorded for a large number (55 each) of wild and cultured samples of the industrially important red seaweed Gracilaria dura to obtain quantitative data of all the metabolites. Average and standard deviation of the respective classes were calculated from 1H NMR spectra wherein significant differences between wild and cultured groups were observed in the 1.56–3.50 ppm region. A significant region in the wild samples having a low average (0–0.98) and standard deviation (0.2–0.81) was 1.56–2.96 ppm representing nitrogen-containing compounds. The same region was found to have a much higher standard deviation (0.13–1.73) with average (0–2.03) in cultured samples. In comparison, sugar metabolites (triethanolamine, galactose, lactate, threonine) have a high average peak intensity and similar standard deviation across both groups of samples. This observation reveals that sugar compounds are critical in central metabolic pathways while nitrogen compounds change due to the environment. PCA analysis revealed an interpretable overview of main information enclosed in a multidimensional data set; the differences were correlated to environmental determinants, developmental, and growth states. A signature metabolite profile is presented with minor standard deviation differences between significant parts of the 1H NMR spectra, confirming its use as a rapid chemo-taxonomic tool supplementary to the conventional approach.

Development &amp; Validation of RP-HPLC Method for the Estimation of Doravirine in Bulk and Pharmaceutical Dosage Form

A simple, accurate, rapid and precise isocratic reversed phase high-performance liquid chromatographic method has been developed and validated for determination of Doravirine in tablets. The chromatographic separation was carried out on Dionex C18 (250 x 4.6mm, 5µ) with a mixture of methanol: 0.05M potassium dihydrogen phosphate (40:60%v/v) as a mobile phase at a flow rate of 1.5 mL/min. UV detection was performed at 306 nm. The retention time was 5.24 min for Doravirine. Calibration plot was linear (r2=0.999) over the concentration range of 200-600 µg/mL. The method was validated for accuracy, precision, specificity, linearity, robustness, LOD and LOQ. The proposed method was successfully used for quantitative analysis of tablets. No interference from any component of pharmaceutical dosage form was observed. Validation studies revealed that method is specific, rapid, reliable, and reproducible. The high recovery and low relative standard deviation confirm the suitability of the method for routine determination of Doravirine in bulk and tablet dosage form.

RP-HPLC Method Development and Validation for the Estimation of Lumefantrine in Bulk Drug

Lumefantrine is an antimalarial agent used to treat acute uncomplicated malaria. It is administered in combination with artemether for improved efficacy. This combination therapy exerts its effects against the erythrocytic stages of Plasmodium spp. and may be used to treat infections caused by P. falciparum and unidentified Plasmodium species, including infections acquired in chloroquine-resistant areas. A reversed-phase high performance liquid chromatography (RP-HPLC) method was developed and validated for the estimation of lumefantrine in bulk drug. The separation was achieved on Thermo C18 analytical column (250 mm × 4.6 mm i.d., 5.0 μm) using 10mM KH2PO4: acetonitrile (pH adjust 3.0 with OPA) in the ratio 20:80 v/v as mobile phase and at a flow rate of 1.0 ml/min. Detection was carried out using a UV detector at 240nm. The total chromatographic analysis time per sample was about 6.0 min with lumefantrine eluting at retention time of about 3.225 ± 0.001min. The method was validated for accuracy, precision, specificity, linearity and sensitivity. Validation studies demonstrated that this HPLC method is simple, specific, rapid, reliable and reproducible. The standard curve was linear over the concentration range of 5-25 μg/ml with r2 close to one (0.999). The limit of detection (LOD) and limit of quantitation (LOQ) obtained for lumefantrine were 0.25 μg/ml and 0.75μg/ml respectively. The high recovery and low relative standard deviation confirm the suitability of the proposed method for the determination of lumefantrine in bulk drugs.

Improvement of Nitrogen-Fertilizer Recommendation by Consideration of Long-Term Site and Cultivation Effected Mineralization

Organic matter (OM) and nutrient nitrogen (N) play vital roles in the fertility and production of soil in accordance with goals of efficient environmental protection. This study aimed to show the extent to which N delivery can contribute to improving nitrogen fertilizer requirements (NFR) through comparative analysis of OM and N. Systems determining the NFR in agricultural practices have thus far been challenged to estimate the annual rate of mineralization of the soil. OM and N turnover was investigated through an available evaluation consisting of 546 representatively distributed permanent test and observation plots (TP) of the German Federal State of Saxony farms. A solid database of at least 10-year field plot card records from 2001 to 2010 was selected for the analysis. A program (BEFU) widely used in agricultural practice, along with the simplified process model CCB, were applied. For the calculation of the amount of mineral N fertilizers used, the results of three different methods for determining the NFR were compared with each other. The determination of the farmers’ demand (=actual condition of the TP) with a mean value of 132 kg N ha−1 did not show a large difference between the calculated values with 137 kg N ha−1 by the BEFU program. Based on the available results for the most important crop species cultivated in Saxony, there were clear differences in the considerations of the N delivery from the soil. The BEFU program was able to calculate an average N delivery of 17 kg N ha−1 from tabulated data, whereas with the CCB process model, 66 kg N ha−1 of mineralization was determined with a distinct higher deviation by taking into account the 10-year field histories. Using the N delivery of the TP by the CCB model, a clear reduction of the mean N fertilization level, to about 80 kg N ha−1, was therefore achieved. These differences were particularly large for TP with organic fertilization (livestock), at a relatively low N fertilization level, and for certain crop species. With a high standard deviation, the average savings potential of mineral N fertilizers was 52–57 kg N ha−1. After including the corrected values for the N mineral fertilization, a decrease in the N balances by an average of 20–25 kg N ha−1 was ultimately achieved. In particular, the heavily oversupplied plots with D and E classification decreased by approximately 50%. The results of our study demonstrate clear improvements; therefore, increased efforts should be made in the future to optimize the determination of NFR using applicable methods that consider N mineralization in agricultural practice and consultation.