Percent Standard Error Research Articles

Integration of artificial neural network, multi-objective genetic algorithm and phenomenological combustion modelling for effective operation of biodiesel blends in an automotive engine

Biodiesel usage is practically restricted as a blended supplement with fossil diesel. In the current study, the authors have attempted to arrive at the optimal biodiesel blend concentrations for an automotive engine. Here, the artificial neural network and genetic algorithm are coupled with phenomenological combustion modelling for the efficient operation of biodiesel blends. The engine experiments are conducted with diesel and diesel-biodiesel blends namely jatropha, and karanja consisting of 120 data points each. This set of data are used for the ANN development and validation. A multi-layer perceptron network is trained by the experimental data for predicting the engine parameters. The Nash Sutcliffe coefficient of efficiency values for the ANN predicted parameters are close to 1, indicating a close prediction. The ANN model predicted the engine output parameters with low values of mean square error, mean square relative error, mean absolute percentage error and standard error of prediction. Optimum values of biodiesel blend fraction, engine speed, brake mean effective pressure, injection pressure and timing are obtained using a multi-objective genetic algorithm. The optimised blend concentration is found to be ∼20% and ∼40% for satisfying the different objectives concerning the overall engine characteristics. Finally, the outputs for the optimised parameters are compared to the validated multi-zone model predictions within the maximum error of ∼3% and 7.9% for performance and emission parameters respectively.

Extended field-of-view ultrasound imaging is reliable for measuring Transversus Abdominis muscle size at rest and during contraction

BackgroundThe strength and size of core muscles, including the abdominal muscles, are crucial to proper function in most activities. Therefore, it is important to reliably assess these characteristics. Our primary objective was to determine if the length, thickness and cross-sectional area of the transversus abdominis (TrA) can be visualized independently from the internal and external abdominal oblique muscles using extended field of view ultrasound imaging at rest and with contraction and to establish its intra- and inter-tester reliability.MethodsTwenty-six individuals were recruited to participate in the study (20 F, 6 M), average age 24.0 years (SD 9.4), height 170.7 cm (SD 8.6) and weight 63.9 kg (SD 9.0). From this total number of participants, two groups of 16 randomly selected participants were assessed to determine intra- and inter-tester reliability respectively. Extended field of view ultrasound images were obtained at three vertebral levels during rest and contraction in the side lying position for both the right and left sides of the trunk.ResultsExcellent intra-tester and inter-tester reliability was seen (ICC range of 0.972 to 0.984). The overall average percent standard error of the measurement for all measurements and locations was approximately 4%. The overall average minimal difference for the thickness measurement for the resting and contraction conditions combined were as follows: intratester 0.056 (0.014) cm and intertester 0.054 (0.017) cm, for area intratester 0.287 (0.086) cm2 and intertester 0.289 (0.101) cm2 and for length intratester 0.519 (0.097) cm and intertester 0.507 (0.085) cm.ConclusionsExtended field of view ultrasound imaging is an effective method of reliably capturing clear images of the TrA during rest and contraction. It provides an efficient mechanism for the analysis of muscle morphology by being able to measure the cross-sectional area, thickness, and length on one image. This methodology is recommended for studies investigating TrA function and training.

Modeling of Lake Malombe Annual Fish Landings and Catch per Unit Effort (CPUE)

Forecasting, using time series data, has become the most relevant and effective tool for fisheries stock assessment. Autoregressive integrated moving average (ARIMA) modeling has been commonly used to predict the general trend for fish landings with increased reliability and precision. In this paper, ARIMA models were applied to predict Lake Malombe annual fish landings and catch per unit effort (CPUE). The annual fish landings and CPUE trends were first observed and both were non-stationary. The first-order differencing was applied to transform the non-stationary data into stationary. Autocorrelation functions (AC), partial autocorrelation function (PAC), Akaike information criterion (AIC), Bayesian information criterion (BIC), square root of the mean square error (RMSE), the mean absolute error (MAE), percentage standard error of prediction (SEP), average relative variance (ARV), Gaussian maximum likelihood estimation (GMLE) algorithm, efficiency coefficient (E2), coefficient of determination (R2), and persistent index (PI) were estimated, which led to the identification and construction of ARIMA models, suitable in explaining the time series and forecasting. According to the measures of forecasting accuracy, the best forecasting models for fish landings and CPUE were ARIMA (0,1,1) and ARIMA (0,1,0). These models had the lowest values AIC, BIC, RMSE, MAE, SEP, ARV. The models further displayed the highest values of GMLE, PI, R2, and E2. The “auto. arima ()” command in R version 3.6.3 further displayed ARIMA (0,1,1) and ARIMA (0,1,0) as the best. The selected models satisfactorily forecasted the fish landings of 2725.243 metric tons and CPUE of 0.097 kg/h by 2024.

I-Bin: Weight Based IoT Smart Recycling Scheduler for Guarded Neighbourhood

Overpopulation and lack of awareness are the main causes of poor waste management. While existing research in waste management employs current technology such as the Internet of Things, it lacks emphasis on residential centric type of waste management system. This project designs a weight based scheduling system for a guarded neighbourhood using Arduino Uno, load cells and plastic bins which are then incorporated with WiFi to send waste weight information in real time to cloud for monitoring.Design verification tests such as the linearity test and non-repeatability test showed less than 1 percent standard deviation error. A Proof of Concept test was conducted to test the system's performance at a guarded residential area.Analysis of test showed that an average of 0.0966kg of recyclable waste was collected per house. Based on theresults also, it is predicted that approximately 483kg of waste can be effectively collected from 10 residential areas using the I-Bin system. Residents tend to dispose waste after office hours and scheduling more waste collection frequency after office hours will lead to increased revenue for the recycling company.

Moisture Sorption Studies of Kamsa:

The study was aimed at establishing storage stability indices of a traditional smoke dried product kamsa, produced from beef. The sample was produced using a standardized method and stored over a period of six months. Data for sorption studies was generated between the temperature ranges of 33.8oC to 50oC for adsorption and desorption using the gravimetric method. The data was analyzed using the Guggeinheim Anderson de Boer (GAB) and the Brunaeur Emmett Teller (BET) model equations. A nonlinear regression analysis method was used to evaluate the constants of the sorption equations. From the results using the GAB model, the monolayer moisture content (Mo) decreased from 0.021 to 0.008gH2O/g solids; the value of the constant K, increased from 0.587 to 1.052; and the value of CG decreased from 2.481 to 2.154. For desorption, the value of Mo decreased from 0.021 to 0.004g H2O/g solids; K increased from 0.587 to 1.035; CG increased from 2.173 to 2.646. The model gave low percent standard error values. The correlation coefficient (R) values obtained for both adsorption and desorption ranged from 0.998 to 0.999, and 0.991 to 1.000, respectively. The Mo values using the BET model at 33.8oC for both adsorption and desorption were 0.055, 0.055, 0.052, 0.049, 0.058, 0.055g H2O/g solid; and 0.057, 0.057, 0.052, 0049, 0.052, 0.057g H2O/g solid, respectively. At 50oC, the adsorption and desorption monolayer moisture values were 0.039, 0.047, 0.049, 0.049, 0.052, 0.058 gH2O/g solids; and 0.054, 0.047, 0.052, 0.052, 0.039, 0.052 gH2O/g solids, respectively. The study concluded that, the GAB model was more suitable in describing the sorption characteristics of Kamsa within the prescribed water activity and temperature ranges.

Moisture Sorption Studies of Kamsa:

The study was aimed at establishing storage stability indices of a traditional smoke dried product kamsa, produced from beef. The sample was produced using a standardized method and stored over a period of six months. Data for sorption studies was generated between the temperature ranges of 33.8oC to 50oC for adsorption and desorption using the gravimetric method. The data was analyzed using the Guggeinheim Anderson de Boer (GAB) and the Brunaeur Emmett Teller (BET) model equations. A nonlinear regression analysis method was used to evaluate the constants of the sorption equations. From the results using the GAB model, the monolayer moisture content (Mo) decreased from 0.021 to 0.008gH2O/g solids; the value of the constant K, increased from 0.587 to 1.052; and the value of CG decreased from 2.481 to 2.154. For desorption, the value of Mo decreased from 0.021 to 0.004g H2O/g solids; K increased from 0.587 to 1.035; CG increased from 2.173 to 2.646. The model gave low percent standard error values. The correlation coefficient (R) values obtained for both adsorption and desorption ranged from 0.998 to 0.999, and 0.991 to 1.000, respectively. The Mo values using the BET model at 33.8oC for both adsorption and desorption were 0.055, 0.055, 0.052, 0.049, 0.058, 0.055g H2O/g solid; and 0.057, 0.057, 0.052, 0049, 0.052, 0.057g H2O/g solid, respectively. At 50oC, the adsorption and desorption monolayer moisture values were 0.039, 0.047, 0.049, 0.049, 0.052, 0.058 gH2O/g solids; and 0.054, 0.047, 0.052, 0.052, 0.039, 0.052 gH2O/g solids, respectively. The study concluded that, the GAB model was more suitable in describing the sorption characteristics of Kamsa within the prescribed water activity and temperature ranges.

Esparto paper industry wastewater treatment by adsorption onto powdered activated carbon

ABSTRACT The discharge of Esparto paper industrial wastewater (EPIW) of SNCPA Company of Kasserine – Tunisia in nature without any treatment can cause harmful effects to the environment. To reduce this danger, several treatment processes have been implemented, in particular, the adsorption technique. The present original study consists of using powdered activated carbon (PAC) to treat EPIW. The tests were carried out on different chemical oxygen demand (COD) concentration of EPIW ranging from 2 to 20 g/L. The influence of initial COD concentration, adsorbent dose, pH and contact time were investigated at temperature of 25 ± 2°C. The equilibrium results were modelled and assessed via Freundlich, Langmuir, Temkin and Dubunin–Radushkevich isotherms models. The error analysis was evaluated by three error functions: the average relative error deviation, the Marquardt’s percent standard error deviation and the Sum of the squares of the errors. The results showed that COD removal efficiency, maximum adsorption capacity and colour removal rate were 94%, 190 mg/g and 90%, respectively, for pH = 6, an adsorbent dose of 75 g/L, initial COD concentration of 9.3 g/L and contact time of 60 min. Besides, the main characteristics values of treated EPIW (BOD, TCOD, pH and Salinity) at natural conditions were 200 ± 30 mg O2/L, 1300 ± 50 mg O2/L, 7.2 ± 0.1 and 1.7 g/L ± 0.1, respectively, which were below the ISO-14,000 standards conditions for release in public sewerage system. Furthermore, both the higher value of correlation coefficients (R2) and the lower value of SSE have shown that Freundlich model provided the best fits to adsorption experimental results.

Surface electromyography of the foot: A protocol for sensor placement

BackgroundThe use of surface EMG (sEMG) to record muscle activity is common place yet due to restrictions in technology studies on the intrinsic foot muscles have been limited or only fine wire instruments have been used. AimThis paper looks at the potential reliability of a sEMG protocol for assessing the intrinsic foot muscles. MethodsSix intrinsic muscles were defined using ultrasound and muscle function testing. A protocol for sensor placement was created with repeatability and reliability testing of the protocol conducted by three separate testers on three subjects over two different time frames. Inter tester and Inter session repeatability and reliability was measured with ICC and percentage standard error of measurement. ResultsAlthough there was good correlation between Extensor Digitorum Brevis, Dorsal Interossei, Abductor Digiti Minimi and Flexor Digitorum Brevis there was increased variability and poor correlation for Flexor hallucis Brevis and Abductor Hallucis. The percentage standard error of measurement did not support the high ICC values indicating a lower precision of measurement. SignificanceVariability between testers and sessions shows an inconsistent reliability of sEMG and further work is required with protocols focussing on grouping muscles to improve the understanding of the intrinsic foot muscles.

Spectrophotometric analysis of tablets of nalidixic acid using melted niacinamide as solvent

In the current attempt of research, novel method for spectrophotometric estimation of nalidixic acid in tablets using melted niacinamide as solvent was developed. The main objective behind research is to show “SOLIDS ALSO POSSESS SOLUBILIZING POWER”. The current study deals with novel spectrophotometric analytical technique for quantitative estimation of nalidixic acid in tablets using melted niacinamide as solvent. According to the theory proposed by Maheshwari, each & every substance possesses solubilising power; substance may be a gas, solid or liquid. Niacinamide imbibes large solubilizing power to nalidixic acid and having approximate solubility more than 80 mg per gm of melted niacinamide (135°C) whereas aqueous solubility of nalidixic acid is 0.21mg/ml at room temperature. Calibration curve of nalidixic acid was plotted by recording the absorbances of standard solutions of drug. The absorbances were observed at 330 nm against respective reagent blanks. The percentage label claims were found very close to 100 (100.93± 1.303 and 99.08±1.764) indicating accuracy of the proposed method. Percentage recoveries estimated by the proposed method are close to 100 (99.91±1.303 and 101.74±1.663) with significant low values of percentage deviation and standard error. Thus, it may be concluded that proposed method is simple, safe and precise and excludes use of toxic organic solvents.
 Keywords: Mixed Solvency, Solubilizing Power, Spectrophotometric Analysis, Niacinamide, Nalidixic Acid.

Large Academic Hospital Laboratory Investigates a Major Pre-Analytical Challenge in Africa and Developing Countries

Background: Delay in serum separation from red blood cells in samples collected from most primary healthcare facilities and transported to a laboratory for analysis is of great concern. Standard guidelines state that serum or plasma should be separated from cells within 2 hours of collection. The aim was to determine effects of delayed sample separation on measured biochemical analytes. The objective was to store blood samples in primary collection tubes at 20-25°C post venesection, then separate, and analyse samples of selected analytes. Methods: Multiple sample tubes of whole blood were collected from one of the authors volunteer, and subjected to time delays in centrifugation. The baseline serum was separated from red blood cells within 30 minutes of post venesection to allow adequate coagulation. Twenty analytes were studied using 2 analytical platforms. Percentage variation and standard error method were used to evaluate time-dependent variability in analytes. Total change limit was used to measure significant changes within-run variability for both platforms. Results: Most analytes were stable up to day 3 to 4 on both platforms. Serum CO2, CL, Ca, ALT and ALB were stable up to 8 days when they were measured on Cobas 8000®. BUN, TRIG, TB, CHOL, AST, ALT and ALB were stable up to 10 days on Dimension® CCS. K showed significant changes at 2h on both platforms at initial measurements. It was out-of-range at day 10 on Dimension® CCS. Serum creatinine levels showed substantial changes at day 2 on Dimension® analyzer and on Cobas 8000® at day 3. Conclusions: The study showed stability of wide range of serum analytes at 20-25°C for several days. The acceptable results can be achieved if samples are centrifuged the same day and analyzed later for most of biochemical analytes.

The Five Times Sit-to-Stand Test: safety and reliability with older intensive care unit patients at discharge.

ObjectiveAssess the Five Times Sit-to-Stand Test safety and clinimetric properties in older patients hospitalized in an intensive care unit.MethodsTest safety was assessed according to the incidence of adverse events and through hemodynamic and respiratory data. Additionally, reliability properties were investigated using the intraclass correlation coefficients, standard error of measurement, standard error percentage change, Altman-Bland plot and a survival agreement plot.ResultsThe overall suitability of the Five Times Sit-to-Stand Test was found to be low, with 29.8% meeting the inclusion criteria. Only 44% of the hospitalized patients who met the inclusion criteria performed the test, with no need for discontinuation in any patient. Heart rate (79.7 ± 10.2bpm/86.6 ± 9.7bpm; p = 0.001) and systolic blood pressure (118 ± 21.4mmHg/129 ± 21.5mmHg; p = 0.031) were the only variables that presented a significant statistical increase, with no evidence of exacerbated response to the test. Additionally, no adverse events were reported from participating and both test-retest and interrater reliability were high (intraclass correlation coefficient ≥ 0.99).ConclusionThe Five Times Sit-to-Stand Test was proven to be safe and to have excellent reliability. Its clinical use, however, may be restricted to high-functioning older adults in hospital settings.

Pharmacokinetics and pharmacodynamics of dapagliflozin in combination with insulin in Japanese patients with type 1 diabetes.

AimsTo assess the pharmacokinetics/pharmacodynamics (PK/PD) of dapagliflozin, a sodium‐glucose co‐transporter 2 inhibitor that increases urinary glucose excretion (UGE) and its major metabolite, dapagliflozin‐3‐O‐glucuronide (D3OG), in Japanese patients with type 1 diabetes (T1D) and inadequate glycaemic control (HbA1c 7%‐10%).Materials and methodsJapanese patients (18‐65 years) with inadequately controlled T1D were randomized 1:1:1 to dapagliflozin 5 mg, 10 mg or placebo (n = 14 each) once daily for 7 days, with adjustable insulin. The PK/PD characteristics of dapagliflozin and D3OG were assessed on Day 7. Patients underwent follow‐up evaluation on Days 8 and 14. Adverse events (AEs), hypoglycaemic episodes and events of diabetic ketoacidosis (DKA) were recorded over the treatment and follow‐up periods.ResultsA total of 42 randomized patients received dapagliflozin or placebo. PK variables increased in a dose‐dependent manner. D3OG was generated rapidly, with a median time to maximum plasma concentration of 2.0 hours (1.0‐3.0). The dapagliflozin dose‐UGE relationship was attenuated, with larger insulin dose reductions than anticipated. Mean percent (standard error) changes in total daily insulin dose from baseline to Day 7 were − 36.86% (3.32), −39.13% (2.68) and − 4.97% (5.28) for dapagliflozin 5 mg and 10 mg and for placebo, respectively. No DKA was reported. AEs were consistent with the established dapagliflozin safety profile. There was no increase in hypoglycaemia.ConclusionsThe PK and safety profiles of dapagliflozin in Japanese patients with T1D were consistent with previous studies, but with an unanticipated attenuation of the PD dose‐response measured as UGE.

Alternative fast analysis method for cellulose sponge surface sampling wipes with low concentrations of Bacillus Spores

Environmental sampling is a critical component of the post decontamination verification process following a bioterrorism event. The current work was performed to produce a less labor-intensive method for processing cellulose sponge-wipes used for sampling areas potentially contaminated with low concentrations (i.e., post-decontamination) of Bacillus anthracis spores. An alternative fast-analysis processing method was compared to the processing protocol validated by the Centers for Disease Control and Prevention (CDC) for the Laboratory Response Network (LRN). Glazed tile coupons (1102 cm2) were inoculated with 50, 500, or 5000 spores of Bacillus thuringiensis subsp. kurstaki (Btk), then sampled with cellulose sponges. Sampling was limited to a 25- by 25-cm area and performed in the same manner as the CDC sampling method. Samples were then processed using either the alternative “Fast Analysis” method or the “CDC method”. Three different analysts repeated the tests at each concentration utilizing each method. Mean recoveries, labor time, and potentially hazardous waste produced were compared for the two methods. The mean percent recoveries and standard errors for the samples processed using the “CDC method” were 39.9 ± 6.7, 43 ± 7.6, and 36.8 ± 10.1 for the 5000, 500, and 50 spore loading levels, respectively; compared to 54.2 ± 12.9, 64.2 ± 21.7, and 45.2 ± 8.6 for the “Fast Analysis” method. At each titer tested the “Fast Analysis” method resulted in a statistically significant higher percent recovery. Furthermore, analysts processed samples utilizing the “Fast Analysis” method in less than half the time and generated half as much potentially hazardous waste compared to the “CDC method”.

Additive aboveground biomass equations based on different predictors for natural Tilia Linn

Biomass is a basic quantitative character of forest ecosystem. Biomass data are foundation of researching many forestry and ecology problems. Accurate quantification of tree biomass is critical and essential for calculating carbon storage, as well as for studying climate change, forest health, forest productivity, nutrient cycling, etc. Constructing biomass models is considered a good approach to estimate forest biomass. Based on biomass data of 97 sampling trees of natural Tilia Linn. in Xiaoxing'an Mountains and Zhangguangcai ranges, three additive systems of individual tree biomass equations were developed: based on tree diameter at breast height (D) only, based on tree diameter at breast height and height (H), and based on the best models. The nonlinear seemly unrelated regression was used to estimate the parameters in the additive system of biomass equations. The heteroscedasticity in model residuals was addressed by applying a unique weight function to each equation. The individual tree biomass model validation was accomplished by Jackknifing technique. The results showed that three additive systems of individual tree biomass equations could fit and predict the biomass of Tilia Linn. well (adjusted coefficient of determination Ra2>0.84, mean predicted error percentage MPE<8.5%, mean absolute error MAE<16.3 kg,mean standard error percentage MPSE<28.5%). The biomass equations of stem and aboveground were better than biomass equations of branch, foliage and crown. Adding total tree height and crown factor in the additive systems of biomass equations could significantly improve model fitting performance and predicting precision (Ra2 improved from 0.01 to 0.04, MAE decreased from 0.01 to 4.55 kg), narrow the confidence interval of the predicted value and the biomass of stem, foliage and aboveground were increased more than the biomass of branch and crown. In general, the equations of the additive system based on the best models produced the best model fitting, followed by that of the additive system based on D and H, and that based on D. It was essential to develop biomass model by adding total tree height and crown factor.

English

Bamboo is one of the world’s most important non-timber forest products (NTFPs) which have been advocated for poverty alleviation in many regions. However, in Ethiopia it is utilized below its potential due to lack of scientific knowledge and awareness on its management and utilization. Therefore, the main objective of this study was to investigate the indigenous knowledge of highland bamboo management and utilization practices of local communities in Kokosa woreda. Five kebeles were purposively selected and 196 sample households (HHs) were selected randomly. Primary data was collected through face-to-face interview, direct observation, key informant interview and focus group discussion. The collected qualitative data was analyzed using simple descriptive statistics, mean and percentage values and standard error. The result of the study indicated that, local people have experience of developing bamboo stands using their indigenous knowledge on propagation techniques. Among the propagation techniques, bamboo offsetting (82%) was preferred most, where 89% of the source of bamboo offset was obtained from individual farmers. The local communities have experienced bamboo stand management practices of which fencing the bamboo stands (44%) was most applied followed by compost application (33%). Mean bamboo area coverage is 0.32 ha per household. The average number of bamboo landraces was 4. Bamboo landrace identification criteria used in the area are bamboo diameter (21.31%), length of internodes between nodes (21.20%), bamboo stem color (21.20%) and splitting nature (18.68%). Bamboo is used for a variety of traditional applications including house construction (100%), fencing (100%), fodder (99.48%), household furniture and utensils (92.34%), fuel wood (98.97%) and as cash source (100%). Traditionally, farmers somehow know how to take care for bamboo roots and rhizomes, which is a good habit to sustain bamboo resource utilization. Such habit has to be integrated with modern knowledge as skilled capability of the harvesters for scientific management is required. Key words: Bamboo, harvesting, landrace, management, offset, propagation, utilization.

Investigating the Sediment Yield Predictability in Some Italian Rivers by Means of Hydro-Geomorphometric Variables

In the present work, preliminary results are reported from an ongoing research study aimed at developing an improved prediction model to estimate the sediment yield in Italian ungauged river basins. The statistical correlations between a set of hydro-geomorphometric parameters and suspended sediment yield (SSY) data from 30 Italian rivers were investigated. The main question is whether such variables are helpful to explain the behavior of fluvial systems in the sediment delivery process. To this aim, a broad set of variables, simply derived from digital cartographic sources and available data records, was utilized in order to take into account all the possible features and processes having some influence on sediment production and conveyance. A stepwise regression analysis pointed out that, among all possibilities, the catchment elevation range (Hr), the density of stream hierarchical anomaly (Da), and the stream channel slope ratio (ΔSs) are significantly linked to the SSY. The derived linear regression model equation was proven to be satisfactory (r2-adjusted = 0.72; F-significance = 5.7 × 10−8; ME = 0.61), however, the percentage standard error (40%) implies that the model is still affected by some uncertainties. These can be justified, on one hand, by the wide variance and, on the other hand, by the quality of the observed SSY data. Reducing these uncertainties will be the effort in the follow-up of the research.

Between-day reliability of MyotonPRO for the non-invasive measurement of muscle material properties in the lower extremities of patients with a chronic spinal cord injury

Measuring the muscle properties of patients with spinal cord injuries (SCIs) is important to better understand their biomechanical features. In this study, we sought to evaluate the between-day reliability of MyotonPRO, a handheld device that can measure muscle mechanical properties, and assess whether it is reliable to measure muscle properties over time in patients with SCI. Thirteen men with complete SCIs (age 53.9 ± 6.3 years, height 171.0 ± 5.2 cm, weight 66.1 ± 5.8 kg), and injury levels ranging from L1 to T12, were enrolled. Oscillation frequency; logarithmic decrement; dynamic stiffness; mechanical stress relaxation time; and creep of the biceps femoris, medial and lateral gastrocnemius, rectus femoris, tibialis anterior, and Achilles tendon were measured on consecutive days using MyotonPRO. The intraclass coefficient for most muscles and the Achilles tendon ranged from 0.53 to 0.99 for all parameters. The percentage standard error of the measurement for many parameters in most muscles and the Achilles tendon was less than 10%. Bland-Altman analysis showed a high agreement for all mechanical properties. No significant differences were observed in any muscle or Achilles tendon properties between days (all p > 0.05). These results indicate that the MyotonPRO is reliable for between-day measurements of the mechanical properties of lower limb muscles and Achilles tendon in patients with SCI.

Body mass prediction from femoral volume and sixteen other femoral variables in the elderly: BMI and adipose tissue effects.

The frequently used prediction equations of body mass do not seem appropriate for elderly individuals. Here, we establish the relationship between femoral dimensions and known body mass in elderly individuals in order to develop prediction formulas and identify the factors affecting their accuracy. The body mass linear least-squares regression is based on 17 femoral dimensions, including femoral volume, and 66 individuals. Body proportion and composition effects on accuracy are analyzed by means of the body mass index (BMI) and on a subset sample (n = 25), by means of the masses of adipose, bone and muscle tissues. Most variables significantly reflect body mass. Among them, six dimensions (e.g., biepicondylar breadth, femoral volume, and head femoral diameter) present percent standard errors of estimate ranging from 9.5 to 11% (r = 0.72-0.81) in normal BMI samples. Correlations are clearly lower in samples with normal and abnormal BMI [r = 0.38-0.58; % of standard error of estimate (SEE) = 17.3-19.6%] and not significantly correlated in females (femoral volume) who present high proportions of abnormal BMI and adipose tissue. In the subset, femoral volume is well correlated with bone mass (r = 0.88; %SEE = 7.9%) and lean body mass (r = 0.67; %SEE = 17.2%). Our body mass estimation equations for elderly individuals are relevant since relatively low correlations are recurrent in studies using younger individuals of known body mass. However, age, sex, lifestyle, and skeleton considerations of studied populations can provide information about the relevance of the body mass estimation, which is dependent on the BMI classification and the proportion of adipose tissue. Our general considerations can be used for studies of younger individuals.

Traumatic leaflet injury: comparison of porcine leaflet self-expandable and bovine leaflet balloon-expandable prostheses.

The main goal of this study was to compare the occurrence of post-deployment leaflet injury between prostheses made of porcine and bovine pericardium. Two types of prostheses, self-expandable prostheses with porcine pericardial leaflet on one side and balloon-expandable prostheses with bovine pericardial leaflet on the other side, were used. In each group, crimped prostheses were compared with control non-crimped prostheses. Following a 15-min period of crimping, prostheses were deployed, and their leaflets were removed and subjected to analyses. The analyses included determination of global and local hydraulic conductance of the leaflets, leaflet plasma insudation and microscopic analysis. The results were expressed as percentage (standard error of the mean) or median (interquartile range). A significant increase in the global hydraulic conductance was only observed in the crimped balloon-expandable prostheses: 20.1 (15.5-41.2) ml/h/m2/mmHg vs 12.3 (9.0-15.6) ml/h/m2/mmHg (P = 0.021). Similarly, areas of marked staining (a marker of local hydraulic conductance) were only seen in the bovine pericardium balloon-expandable prostheses. The incidence of leaflet plasmatic insudation was increased in the crimped prostheses compared with the control prostheses. The microscopic study revealed a higher occurrence of traumatic lesions in the crimped prostheses in comparison with the control prostheses: 33.3 ± 21.1% vs 5.5 ± 5.5% (P = 0.039) and 44.4 ± 20.5% vs 5.5 ± 5.5% (P = 0.017) in the bovine and the porcine leaflets, respectively. Post-deployment leaflet injury occurred in both types of prostheses. However, alteration of the global and local hydraulic conductance was important in the bovine pericardium balloon-expandable prostheses.

Aboveground biomass estimation at different scales for subtropical forests in China

BackgroundThe accurate estimation of forest biomass at different scales is the critical step in the assessment of forest carbon stocks. We used three models at increasing scales: allometric model at ecoregional scale (model 1), dummy variable allometric model at both ecoregion and regional scales (model 2), and allometric model at regional scale (model 3) to estimate the aboveground biomass of six subtropical forests in China. Furthermore, we also tested whether wood density can improve the accuracy of the allometric model at regional scale.ResultsAboveground biomass estimates for six subtropical forests were significantly affected by the ecoregions (p < 0.05). Model 1 and model 2 had good fitness with higher values of R2, lower RSE (residual standard error) and MPSE (mean percent standard error) than model 3. The values of MPSE for model 1, model 2, and model 3 ranged from 2.79 to 30.40%, 5.15 to 40.94%, and 13.25 to 80.81% at ecoregion scale, respectively. At regional scale, MPSE of model 2 was very similar to that of model 1, and was less than model 3. New allometric models with wood density had greater R2, lower RSE and MPSE than the traditional allometric models without wood density variable for six subtropical forests at regional scale.ConclusionThe dummy variable allometric models have better performances to estimate aboveground biomass for six subtropical forests in China, which provided an effective approach to improve the compatibility of forest biomass estimations from different scales. New allometric models with wood density substantially improved accuracies of aboveground biomass estimation for subtropical forests at regional scale.