Tests In Conditions Research Articles

Balance performance maintained during dual-task condition with a cognitive task across menstrual cycle

BackgroundDual-task, performing a balance task and a cognitive task simultaneously, has been used as sport-related concussion assessment tool. However, the effect of dual task on balance performance remains controversial. Also, the fluctuation of hormone across menstrual cycle on balance and dual-task performance has not been fully examined.ObjectiveTo examine (1) the effect of dual task on balance performance, (2) the interaction of female sex hormonal level, balance, and dual-task performance.DesignA cohort study.SettingA laboratory of concussion research and services.ParticipantsA group of 49 healthy female college-aged students (age = 21.6 ± 2.0 years).Main outcome measuresThe Stability Evaluation Test (SET) protocol, Balance error scoring system (BESS) test and postural sway velocity (deg/sec) by using VSR SPORT force plate. Three auditory mathematics questions were given for each condition of the SET test. Two single-task conditions were provided, including balance only and math only. Balance test and math questions were given simultaneously during the dual-task condition.ResultsThere was no significantly statistically difference in BESS or sway velocity between single and dual task. However, the performance of math calculation is better in dual-task comparing to the single task (math only), with an 8%–12% higher rate of accuracy, but it didn't reach a statistical significance. The rate of accuracy during the dual task didn't vary among menstrual phases.ConclusionsBalance performance was maintained under dual-task conditions and fluctuation of female sex hormones across the menstrual cycle may not affect working memory and executive function. These findings are potentially clinically applicable to detecting balance deficits and cognitive alterations in female concussed individuals. Future studies are needed to investigate the underlying mechanism of balance maintenance and attention dividend under dual-task conditions.

Trajectories of cognitive decline differ in hippocampal sclerosis and Alzheimer's disease

Hippocampal sclerosis (HS) is a prevalent cause of dementia in the oldest old but is generally misdiagnosed as Alzheimer's disease (AD) due to similarities in clinical presentation. To determine if clinical and cognitive features diverge over time, we compared results from longitudinal evaluations of participants in the University of California, San Diego, Alzheimer's Disease Research Center with autopsy-confirmed AD (n = 195), HS (n = 21), or both HS + AD (n = 18). Each group exhibited decline in all cognitive measures, with HS declining at a slower rate than AD on the Mini-Mental State Examination, immediate recall condition of a word-list learning test, and Dementia Rating Scale total and subtest scores (except memory). Five years before the final evaluation, more prominent semantic and visuospatial deficits were apparent in AD participants than in HS participants despite comparable global cognitive impairment. Groups did not differ on any measure of executive function. HS + AD differed from AD only on the Boston Naming Test. Overall, results suggest that HS dementia is associated with cognitive deficits that progress more slowly than, but generally mimic, those observed in AD.

ВИВЧЕННЯ ГІПОГЛІКЕМІЧНОЇ ДІЇ ФІТОЗАСОБУ, ЩО МІСТИТЬ СУХІ ЕКСТРАКТИ З ЛИСТЯ ШОВКОВИЦІ БІЛОЇ, СТУЛОК КВАСОЛІ ЗВИЧАЙНОЇ І ПАГОНІВ ЧОРНИЦІ ЗВИЧАЙНОЇ

Вступ. Цукровий діабет – це соціальна катастрофа, яка позбавляє життів мільйони людей, і найгіршою тенденцією є те, що дві третини з них мають працездатний вік. Незважаючи на те, що сучасний фармацевтичний ринок представлений широким арсеналом лікарських засобів, які застосовують для профілактики та лікування хворих на цукровий діабет, пошук нових гіпоглікемічних засобів є актуальним завданням сучасної фармації. Завдяки комплексу біологічно активних речовин у рослинах, фітозасоби проявляють багатогранну дію на людський організм, забезпечуючи вплив на різні ланки розвитку діабету та його специфічних і неспецифічних ускладнень при мінімальному ризику токсичних чи алергічних проявів, та можуть слугувати альтернативою для синтетичних цукрознижувальних препаратів.
 Мета дослідження – вивчити гіпоглікемічну дію фітозасобу (комбінація сухих екстрактів з листя шовковиці білої Morus alba L., стулок квасолі звичайної Phaseolus vulgaris L., пагонів чорниці звичайної Vaccinium myrtillus L.).
 Методи дослідження. Дослідження проводили на щурах-самцях лінії Вістар, яким внутрішньошлунково профілактично вводили фітозасіб упродовж 7 днів у різному дозуванні. Як референс-препарати було використано: настій з лікарського збору “Арфазетин”, суспензію таблеток “Метформін”. Визначали концентрацію глюкози у крові тварин натще (до та після введення відповідних засобів), а також за умов проведення орального тесту толерантності до глюкози.
 Результати й обговорення. В усіх дослідних групах, тварини яких отримували фітозасіб, спостерігали зниження базальної глікемії після семиденного профілактичного введення, а також зменшення розвитку глікемії за умов проведення орального тесту толерантності до глюкози. Гіпоглікемічна дія фітозасобу в дозуванні з розрахунку 100 мг/кг сухого екстракту з листя шовковиці білої є порівнюваною з дією препарату “Метформін” та достовірно перевищує дію настою з лікарського збору “Арфазетин”.
 Висновки. Отримані результати дослідження вказують на виражену гіпоглікемічну дію фітозасобу, що містить сухі екстракти з листя шовковиці білої, стулок квасолі звичайної і пагонів чорниці звичайної. Подальше вивчення гіпоглікемічної дії досліджуваного фітозасобу буде здійснено в обраному дозуванні – з розрахунку 100 мг/кг сухого екстракту з листя шовковиці білої.

The Fatigue Strength and Failure Mode of Coal Sample Subjected to Cyclic Loading

In order to study the fatigue strength and failure characteristics of coal samples, a series of multilevel cyclic loading tests were carried out. The test results show that: (1) When the confining pressure corresponds to 0, 5 and 10 MPa, the fatigue strength of coal samples at a frequency of 0.5 Hz is slightly larger than that with a frequency of 0.25 Hz. (2) For fatigue failure, the circumferential strain is more sensitive than that of axial strain. (3) In the condition of conventional compression test, it is favorable for larger scale cracks to growth and rapid development when the broken degree of coal samples is low. In the long-term cyclic loading test, it is beneficial to produce small cracks. The coal sample is more broken in this case.

Simulation of in situ oil reservoir conditions in a laboratory bioreactor testing for methanogenic conversion of crude oil and analysis of the microbial community

A bioreactor was designed and established to simulate in situ oil reservoir conditions for investigating methanogenic conversion of crude oil by microbial community derived from production water of a high-temperature oilfield. The continuous incubation and culturing were divided into two phases (Phase I, day 0–341; and Phase II, day 341–520) to allow sampling and supplement of fresh culture medium on day 341 and 520, respectively. The average methane production rate was 4.9 and 20.8 mmol CH4·day−1 m−3 pore volume during the Phase I and Phase II, respectively. Degradation intermediates of fatty acids were detected in the culture fluids indicating the transformation of crude oil. The 16S rRNA gene sequence analysis revealed that the major bacterial community shifted from Deferribacteres to Aminicenantes and unclassified Bacteria, as well as Thermotogae and Synergistetes. The predominant methanogenic community shifted from methylotrophic methanogen (Methanolobus) to hydrogenotrophic methanogens (Methanothermobacter and Methanocalculus) and acetoclastic methanogen (Methanothrix) after 341 days of incubation, and was subsequently dominated by hydrogenotrophic methanogen (Methanothermobacter) after 520 days of incubation. This study expanded our understandings of methanogenic oil-degrading processes and the key microorganisms involved in laboratory simulation bioreactor over time of incubation. In addition, it further provides valuable insights on the microbial conversion of hydrocarbons to methane for enhancing the energy recovery from residual oil in petroleum reservoirs.

Vestibulo-Hippocampal Function Is Enhanced and Brain Structure Altered in Professional Ballet Dancers.

Background and Objective: Life-long balance training has been shown to affect brain structure, including the hippocampus. Data are missing in this respect on professional ballet dancers of both genders. It is also unknown whether transfer effects exist on general balancing as well as spatial orientation abilities, a function mainly supported by the hippocampus. We aimed to assess differences in gray matter (GM) structure, general balancing skills, and spatial orientation skills between professional ballet dancers and non-dancers.Methods: Nineteen professional ballet dancers aged 18–35 (27.5 ± 4.1 years; 10 females) and nineteen age-matched non-dancers (26.5 ± 2.1 years; 10 females) were investigated. Main outcomes assessed were the score of a 30-item clinical balance test (CBT), the average error distance (in centimeters) on triangle completion task, and difference in GM density as seen by voxel-based morphometric analysis (VBM, SPM).Results: Ballet group performed significantly better on all conditions of the CBT and in the wheelchair (vestibular-dependent) condition of the spatial orientation test. Larger GM volumes for ballet dancers were observed in the right hippocampus, parahippocampal gyrus, insula, and cingulate motor cortex, whereas both larger and smaller volumes were detected within cerebellum bilaterally in comparison to non-dancers.Conclusion: Our results indicate that life-long ballet training could lead to better clinically relevant balancing abilities as well as vestibular-dependent spatial orientation capabilities; both of the benefits might be caused by positive influence of ballet training on the vestibular system function, and—possibly—its connectivity with temporal lobe regions responsible for vestibular-dependent orienting in space.

Effect of static hydrogen charging on corrosion and hydrogen embrittlement of High strength steel

The corrosion and hydrogen embrittlement properties of 1000MPa grade high strength steel in sea water are studied by weightlessness test under the condition of cathode polarization and slow strain tensile test (SSRT) after static hydrogen filling . The fracture characteristics of the specimen are observed with SEM. The results show that the most positive cathodic protection potential of high strength steel in sea water is -780 mV. The tensile test shows that with the negative shift of the polarization potential and the increase of hydrogen charging time, the elongation and the shrinkage of the high strength steel decrease gradually. The fracture mode transforms from ductile to cleavage and intergranular fracture. It can be seen that the toughness of the material decreases and the hydrogen embrittlement sensitivity increases gradually. Especially, the effect of polarization potential on hydrogen embrittlement of materials is more obvious.

A7206 Morning Blood Pressure Surge predicts lower performances in task-switching and processing speed in the elderly

Objectives: While higher morning systolic blood pressure surges (MBPS) have been associated to increased stroke risk, the association with cognitive performances remains unknown. Our aim is to determine which method for calculating MBPS is the best predictor of performances in task-switching and processing speed in both elderly normotensives (NT) and hypertensives (HT). Methods: We divided 103 participants, aged 60 to 75 years old, into three groups: NT not receiving anti-hypertensive treatment (n = 49), HT receiving treatment and controlled for blood pressure (BP) (n = 28) and refractory HT (n = 26). They were evaluated for ambulatory BP and cognitive functions using a battery of neuropsychological tests. Four methods for calculating MBPS (pre-waking surge, morning-evening surge, rising-BP surge and sleep-through surge) were selected and used individually as independent determinants in multiple linear regression models with group, age, sex, years of schooling while using preselected cognitive variables as outcomes. Results: Models using pre-waking surge (morning BP minus pre-awake BP) were significant predictors of “number of errors in the Trial Making Test Part B (TMTB)” (p = 0.018), “the number of switching errors in TMTB” (p = 0.005), and “the reading condition of the Color-Word Interference Test” (p = 0.031), while models using morning-evening surge (morning BP minus evening BP) were significant predictors of “the number of errors in TMTB (p = 0.036), “the number of switching errors in TMTB” (p = 0.02). Conclusion: Pre-waking surge and morning-evening surge models were the most successful in predicting task-switching performance and processing speed. These suggests that they could be used as predictors of performance in cognitive flexibility tasks and of processing speed in the elderly, independently of their BP-related category.

Correction to: Computational Verification of the Optimum Boundary Condition of the Brazilian Tensile Test

An erratum has been detected in the units of the Young’s modulus of Tables 5 and 6. The units should be in GPa and not in MPa.

Preparation and Ablation Performance of BN Fiber Fabrics Reinforced Nitrides Composites

High-performance three-dimensional boron nitride fiber reinforced silicon nitride (BNf/Si3N4) composites were prepared by the infiltration and pyrolysis (PIP) process using BN fiber fabrics as the reinforcing body and excellent nitride organic precursor (Perhydropolysilazane, PHPS) as the Impregnated liquid. The ablation resistance of the composite was evaluated by plasma jet ablation test in air. The results show that a uniform and dense interface layer is formed on the fiber surface, with thickness is about 100 nm, and the XRD test shows that it is hexagonal BN (h-BN). The density of the composite reaches more than 1.72 g·cm-3 and the bending strength is more than 80 MPa. Under the condition of plasma jet ablation test at 2000 °C / 200 s, the mass ablation rate is 3.32 × 10-4 g/s, the linear ablation rate is 4.78 × 10-3 mm/s. The prepared materials have excellent resistance to high temperature ablation, and are expected to be used in the field of high temperature microwave transparent such as high mach missile radome, antenna window and so on.

Numerical simulation and experimental study of electrocoagulation grid flocculation tank.

In recent years, electrocoagulation has been extensively studied on the removal of refractory pollutants. However, the application of electrocoagulation in actual flocculation tank is limited because of its high energy consumption, especially under the condition of large electrode plate spacing. In this study, the computational fluid dynamics (CFD) software - ANSYS Fluent had been used to simulate the flow state of grid flocculation tank, for the purposes of optimizing the design parameters. The simulation results showed that vortex velocity gradient was stronger, the grid plate spacing was smaller when the velocity was 0.13 m s-1, perforation size was 25 × 25 mm, porosity was 31.25%. And the optimal grid plate spacing was 250 mm. Moreover, in order to prove the reasonableness of simulation results, the humic acid wastewater was treated by electrocoagulation process in the specific device which was built based on simulation results. The results showed that the optimal condition of orthogonal test were as follows: the initial pH was 8, the concentration of sodium chloride was 5 mmol L-1, the voltage was 15 V; and the power time was 60 min. This study greatly narrowed the grid plate spacing, optimized design parameters under the circumstances of strong turbulent intensity and provided a theoretical basis for the combination of electrocoagulation and hydraulic flocculation.

Computational Verification of the Optimum Boundary Condition of the Brazilian Tensile Test

The present research analyses the configuration of jaws to avoid the premature failure of the disc in the Brazilian test. The objective is to depict the loading device configuration that most likely produces results comparable to the Hondros’ analytical stress solution. To this end, several numerical analyses have been carried out for different contact angles with the finite element method. It was deduced that the final contact angle plays an important part in the success of the Brazilian test and that the Griffith criterion can be fulfilled if the equivalent stress is calculated. Additionally, the orientation of the forces in the contact between the loading device and the disc has been studied for different friction conditions. According to the numerical results, it was found that a loading arc configuration of 20° shows the best agreement with the probable values given by the analytical stress model when the uncertainty of its magnitudes is taken into account. The study also demonstrates that the friction in the contact between the optimal loading configuration and the disc does not seem to significantly affect the theoretical predictions in the centre of the disc.

Safety Helmet Implementation with Centralized Information System on Remote Monitoring Applications

Personal Protective Equipment (PPE) is standard equipment that required to ensure safety of workers. PPE equipment that used during work such as: Safety helmet, safety glass, and ear plug. PPE that being used by workers doesn’t informative yet, only serve as personal protective so evacuation prevention still looks difficult to do prior accident happened. In this research, Safety Helmet Project has been implemented with pulse sensor, temperature sensor, carbon monoxide gas sensor, and transmission media which able transmitting data to control and monitoring center. The system also supports multiuser monitoring applications that can be accessed simultaneously through the internet network. Based on test results, the comparison of measurement gap with standard tool has been obtained as temperature sensor is 0,07%, heart sensor is ± 4%. Accuracy level for temperature sensor and heart rate are 99,67% and 95,45% by various condition of test. Another test is delay of the transmitting sensor data to the website around ± 10 seconds and controlling around ± 5 seconds.

Sexual abuse but not posttraumatic stress disorder is associated with neurocognitive deficits in South African traumatized adolescents

ObjectivesNeurocognitive impairments are commonly observed in adults suffering from posttraumatic stress disorder (PTSD). The picture is less clear in adolescents. Childhood sexual abuse (CSA) may have an independent influence on neuropsychological test performance and provide partial explanatory power of the inconsistent findings. We hypothesized that adolescents with PTSD who have also suffered sexual abuse would have most pronounced deficits on neurocognitive testing. MethodsIn a cross-sectional design, 105 traumatized South African adolescents, of whom 52 fulfilled criteria of PTSD and 34 reported CSA, were studied. A comprehensive neurocognitive battery including tests of memory, executive functioning, and language was used to analyze the associations of neurocognitive impairments with PTSD and CSA. ResultsAdolescents reporting CSA manifested impairments in proactive and retroactive interference tasks on the Rey Auditory Verbal Learning test and in the copy condition of the Rey Osterrieth figure test, indicating deficits in attention and working memory. Against our hypothesis, no independent effects of PTSD were found on neurocognitive performance. Results were independent of comorbid psychiatric diagnoses. ConclusionsSexual abuse seems to have an independent influence on attention and working memory. This could be an early sign of hippocampal impairment.

Whole blood n-3 fatty acids are associated with executive function in 2–6-year-old Northern Ghanaian children

Several studies demonstrate the importance of essential fatty acids (EFAs), and the long chain polyunsaturated FA docosahexaenoic acid (DHA), on cognition and brain development. The objective of this study was to investigate the relationship between whole-blood FAs and executive function in children from Northern Ghana. A total of 307, 2-to-6-year-old children attempted the dimensional change card sort (DCCS) task to assess executive function, and dried blood spot samples were collected and analyzed for FA content. Significant differences in mean % total whole-blood fatty acids were observed between children who could not follow directions on the DCCS test (49.8% of the sample) and those who could (50.2% of the sample). Positive associations with DCCS performance were observed for DHA (β=0.25, P=.06), total n-3 (β=0.17, P=.06) and dihomo-gamma-linolenic acid (DGLA; β=0.60, P=.06). Children with the highest levels of total n-3 and DHA were three and four times, respectively, more likely to pass at least one condition of the DCCS test of executive function than those with the lowest DHA levels. The results of this study indicate an association between n-3 FAs and high-level cognitive processes in children two to six years of age, providing impetus for further studies into possible interventions to improve EFA status of children in developing countries.

РЕАКЦИЯ СОРТОВ ГОРОХА ПОСЕВНОГО НА АБИОТИЧЕСКИЕ УСЛОВИЯ

The problem of reaction of varieties or hybrids of field crops to abiotic factors has always been key in crop production. Further research is needed in this direction because of the advent of new varieties of pea seed. The purpose of the research is to determine the reaction of pea varieties on abiotic conditions in the competitive varietal testing by the formation of productivity on government consignments of the Udmurt Republic. Research tasks: analysis of yields of seven varieties of peas in four state stations; identify the most productive varieties in different abiotic conditions. The object of research: pea varieties Aksayskiy usatyy, Krasnous, Marafon, In memory of Khangildin, Stabil, Tomas, Yamal 2.

Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate fracture fixation devices.

ObjectivesSecondary fracture healing is strongly influenced by the stiffness of the bone-fixator system. Biomechanical tests are extensively used to investigate stiffness and strength of fixation devices. The stiffness values reported in the literature for locked plating, however, vary by three orders of magnitude. The aim of this study was to examine the influence that the method of restraint and load application has on the stiffness produced, the strain distribution within the bone, and the stresses in the implant for locking plate constructs.MethodsSynthetic composite bones were used to evaluate experimentally the influence of four different methods of loading and restraining specimens, all used in recent previous studies. Two plate types and three screw arrangements were also evaluated for each loading scenario. Computational models were also developed and validated using the experimental tests.ResultsThe method of loading was found to affect the gap stiffness strongly (by up to six times) but also the magnitude of the plate stress and the location and magnitude of strains at the bone-screw interface.ConclusionsThis study demonstrates that the method of loading is responsible for much of the difference in reported stiffness values in the literature. It also shows that previous contradictory findings, such as the influence of working length and very large differences in failure loads, can be readily explained by the choice of loading condition.Cite this article: A. MacLeod, A. H. R. W. Simpson, P. Pankaj. Experimental and numerical investigation into the influence of loading conditions in biomechanical testing of locking plate fracture fixation devices. Bone Joint Res 2018;7:111–120. DOI: 10.1302/2046-3758.71.BJR-2017-0074.R2.

On the generalization of the Salem test

The assertion that the Salem test [5] for the uniform convergence of a trigonometric Fourier series is improvable, is proved. In particular, an example of a continuous function, which does not fulfill the condition of the Salem test but satisfies the condition of the generalized Salem test [10], is constructed. Besides, the theorem which improves Golubov’s [3,4] result for continuous functions of two variables, is given.

Effects of temperature and temperature gradient on concrete performance at elevated temperatures

To assure adequate fire performance of concrete structures, appropriate knowledge of and models for performance of concrete at elevated temperatures are crucial yet currently lacking, prompting further research. This article first highlights the limitations of inconsistent thermal boundary conditions in conventional fire testing and of using constitutive models developed based on empirical data obtained through testing concrete under minimised temperature gradients in modelling of concrete structures with significant temperature gradients. On that basis, this article outlines key features of a new test setup using radiant panels to ensure well-defined and reproducible thermal and mechanical loadings on concrete specimens. The good repeatability, consistency and uniformity of the thermal boundary conditions are demonstrated using measurements of heat flux and in-depth temperature of test specimens. The initial collected data appear to indicate that the compressive strength and failure mode of test specimens are influenced by both temperature and temperature gradient. More research is thus required to further quantify such effect and also to effectively account for it in rational performance-based fire design and analysis of concrete structures. The new test setup reported in this article, which enables reliable thermal/mechanical loadings and deformation capturing of concrete surface at elevated temperatures using digital image correlation, would be highly beneficial for such further research.

Test Conditions in Macular Visual Field Testing in Glaucoma.

The purpose of this study is to evaluate the suitable visual field (VF) test conditions (target size, test type, and eccentricity) for the macular region, we investigated the correlations between the ganglion cell layer (GCL) thickness and 6 VF test results. We tested 32 eyes of patients (61.1±9.2 y) with preperimetric (6), early-stage (16), and moderate-stage (10) glaucoma. The VF tests included 3 SAP (the 10-2 HFA using SITA with target size III [HFA SITA (III)], full threshold with size III [HFA FULL (III)] and size I [HFA FULL (I)]) and 3 visual function-specific perimetry tests (the 10-2 SWAP, 10-2 flicker, and 10-2 Humphrey Matrix). The GCL and inner plexiform layer (GCL+IPL) thickness was measured by Spectral Domain Optical Coherence Tomography (SD-OCT) with a macular 7×7 mm cube scan (3D OCT-2000, Topcon). The coefficient of determination (r) for the correlation between visual sensitivity and the GCL+IPL thickness was calculated for each test at eccentricities 0 to 5 degrees, 5 to 7 degrees, and 7 to 10 degrees using linear and quadratic regressions. All 6 tests showed the strongest correlation with the GCL+IPL thickness at 5 to 7 degrees. The respective r (linear) and R (quadratic) for HFA SITA (III), HFA FULL (III), HFA FULL (I), SWAP, Flicker, and Matrix were (0.40, 0.50), (0.43, 0.53), (0.44, 0.46), (0.51, 0.51), (0.33, 0.34), and (0.52, 0.52). As compared with the frequently-used SAP with a size III, SAP with size I and the function-specific perimetry tests (especially the Matrix) could be more suitable for testing the macular region.