Limit Of Deviation Research Articles

Torsional strabismus and vertical rectus muscle surgery in thyroid eye disease

To assess the torsional component in patients with vertical strabismus due to thyroid eye disease (TED) and its course after vertical rectus muscle surgery. Retrospective chart review of patients undergoing vertical strabismus surgery for TED between 1998 and 2017, having undergone pre- and postoperative Harms tangent screen examination. Forty patients (27 women) were identified. A torsional component was present in all patients. Thirty-three patients had a mean excyclotorsion of 4.5° in primary position, increasing to 8.2° in upgaze, associated with restricted elevation. Inferior rectus muscle recession (n=29) reduced the excyclotorsion in all cases. A 4.4° mean incyclotorsion was present in primary position in 7 cases, increasing to 7.1° in downgaze. Superior rectus muscle recession reduced the incyclotorsion in 5/6 cases. The torsional surgical dose-effect relationship was correlated with the amount of preoperative torsion. The field of binocular single vision improved from 6.5% preoperatively to 71.1% after surgery. Ocular torsion is common in vertical strabismus secondary to TED and is significantly improved by vertical rectus muscle surgery alone. Surgery should be planned according to vertical deviation and motility limitation, and vertical rectus muscles surgery should be considered the first line of treatment, with selective oblique muscle surgery as a second-line option, which was unnecessary in our series.

Determination of Trace Ziram in Food by Magnesium Hydroxide Coprecipitation with Indirect Detection by Flame Atomic Absorption Spectrometry (FAAS)

The co-precipitation technique is frequently employed for the separation and enrichment of trace elements. The aim of this technique is to separate the analytes from the matrix with the help of the precipitating ion and the carrier ion without the need for a solid phase and/or liquid phase solvent. A separation-preconcentration method based on the co-precipitation of ziram (zinc bis (dimethyldithiocarbamate) in vegetable samples using magnesium hydroxide was developed prior to its indirect determination by flame atomic absorption spectrometry (FAAS). Zinc levels in ziram were determined by FAAS. The ziram concentration was calculated using the stoichiometric relationship between zinc and ziram. The analytical parameters including hydroxide ion concentration, Mg (II) as the carrier element, and model solution volumes were optimized. In addition, possible interferences were investigated. The preconcentration factor was calculated to be 60. The limit of detection (LOD) and relative standard deviation were 35 μg L−1 and 3.9%. The presented method was successfully applied to the analysis of water and vegetable samples.

A Simple, Efficient, Eco-Friendly Sample Preparation Procedure for the Simultaneous Determination of Hormones in Meat and Fish Products by Gas Chromatography-Mass Spectrometry.

Food safety can be severely compromised by the presence of chemical contaminants. This has raised a pressing need to develop efficient analytical methods for their determination at very low levels in complex food matrices. In this manuscript, we developed a simple, sensitive, fast, green analytical method for the determination of thirteen natural and synthetic hormones from different families including progestogens, estrogens and androgens in meat and fish products. The method involves direct extraction with a (9:1) acetonitrile–water mixture and subsequent purification of the extract by semi-automated solid-phase extraction on a sorbent column (hydrophilic–lipophilic copolymer of N-vinylpyrrolidone and divinylbenzene). This treatment enriches samples with the target compounds while removing proteins, lipids and other potential interferences from their matrix for the accurate determination of the analytes by gas chromatography–mass spectrometry, all within 15 min. The proposed method exhibits good linearity (r ≥ 0.996), low limits of detection (0.4–15 ng/kg), acceptable recoveries (90–105%) and relative standard deviations (≤7%); in addition, it is scarcely subject to matrix effects (1–20%). The method was successfully used to determine natural and synthetic hormones in meat and fish products from Spain, Portugal, Italy, Germany, Greece, Norway, Morocco and the USA. The analytes were found at especially high levels (30–1900 ng/kg) in mussels, beef and pork.

The influence of the Yumeiho therapy procedure on central hemodynamics and its assessment

The purpose of the study was to determine changes in central hemodynamics under the influence of the Yumeiho therapy procedure and to develop criteria for their evaluation Material & Methods: 55 people who received Yumeiho therapy procedures at the "Yumeiho" center in Lviv were under supervision. Of them, 29 women aged 38.7 (32.0; 52.4) years and 26 men aged 35.8 (29.0; 46.6) years. The average age of the examinees was 37.5 (31.5; 47.2) years. All individuals had non-specific signs of manifestations of osteochondrosis of the spine. The methodology for the study of the indicators of the cardiovascular system involved the recording of blood pressure (BP) and heart rate (HR) in the supine position after 5 minutes of rest before the procedure, as well as after 5 minutes of rest in the supine position after the completion of the Yumeiho therapy Results: stroke volume (SV, cm3), cardiac output (CO, dm3), general peripheral vascular resistance (GPVR, dyn/s/cm−5), cardiac index (CI, dm3/m2) and stroke index (SI, cm3/m2) were calculated according to known formulas. The analysis of changes in hemodynamic parameters during 1014 procedures was carried out. It is shown that in the Yumeiho-therapy procedure, there is a significant decrease in SV, CO, CI, SI and an increase in GPRV, both in men and in women. There is a decrease in the kinetics of blood circulation to the hypokinetic level. Conclusions: the conducted study made it possible to establish that under the influence of Yumeiho therapy in patients there is a significant decrease in SV (cm3), CO (dm3), CI (dm3/m2), SI (cm3/m2), and a significant increase in GPRV (dyn/s/cm–5). According to the apriori data of the percentile analysis of changes in hemodynamic parameters, the limits of pronounced deviations, which may indicate an inadequate reaction of the body to the procedure, are established. That is, the obtained results can be useful during operational control of the effect of the Yumeiho therapy procedure on the patient's body. In the future, it is possible to consider the use of Yumeiho therapy in cardiac patients.

A label-free strategy for H2O2 assay by chemical vapor generation-atomic fluorescence spectrometry

Hydrogen peroxide (H2O2) plays an essential role as a signal molecule in regulating diverse biological processes. It is of practical significance for accurately detecting the concentration of H2O2. In this work, a simple and label-free method was developed for H2O2 assay by chemical vapor generation-atomic fluorescence spectrometry (CVG-AFS). The assay was based on the phenomenon that l-Cysteine (l-Cys) can inhibit the AFS signal of As(III), while l-Cys can be oxidized to cystine by H2O2 and I-. Therefore, the concentration of H2O2 was proportion to the AFS signal. Under the optimal experimental conditions, a good linear range from 50 μM-4 mM was obtained, and the limit of detection (LODs) and relative standard deviation (RSD, n = 7) were calculated to be 9.9 μM and 0.4%, respectively. The proposed method has been successfully applied for H2O2 assay in medical disinfectants with good recoveries. It has the advantages of simple and cost-effective.

Performance analysis of capacitor voltage balancing in modular multilevel converter by sorting algorithm

<span lang="EN-US">Due to the modularity of modular multilevel converter (MMC), therefore it has been considered as a substitute for the diode-clamp multilevel inverter in applications of high-voltage high-power. Where it can obtain any level of voltage without imposing complexity on the control system. This study analyses in detail the operation principle and balances the capacitor voltage of sub-module (SM) in modular multilevel converter by sorting algorithm. The output voltage control and capacitor voltage balancing technique are confirmed by MATLAB/Simulink and the obtained result has been discussed, where the capacitor voltage of the sub-module has controlled within the acceptable deviation limit, which is 5-10%. In addition, the circulating current has been controlled and reduced.</span>

Modeling of heat transfer in a narrow rectangular channel with partial swelling blockage

In plate-fuel-assembly reactor cores, owing to the cladding swelling caused by irradiation damage under high burnup conditions, narrow rectangular channels may be partially blocked. The partial blockage will alter the flow channel shape and affect the heat transfer characteristics. Thus, it is important to focus on the flow and heat transfer characteristics under partial blockage conditions. Accordingly, in this study, the heat transfer at the entrance region of a narrow rectangular channel with protrusions is numerically investigated. Further, variations in the local Nusselt number and fluid field distribution are studied. Results reveal that the protrusions lead to a wake effect that influences the local heat transfer in the blockage region and wake zones. At the upwind face of the protrusions, the local heat transfer increases to a crest value over the hydraulic diameter. A low-speed recirculation region is also formed over a short distance at the intermediate leeward face of the protrusion, resulting in local deterioration of the heat transfer. Moreover, in the wake zone, heat transfer is enhanced owing to the disturbance of the flow streams with different velocities. The effects of the blockage ratio, number, and interval of protrusions on the local heat transfer are also analyzed. This augmentation of the heat transfer decreases with an increase in the Reynolds number, whereas it increases with the height ratio of the protrusions. Additionally, a multiple regression analysis method is employed to analyze the numerical simulation data. Based on these numerical investigations, dimensionless correlations are proposed to estimate the local Nusselt number for rectangular channels with and without partial swelling blockages. The predicted results are in good agreement with the experimental data and reference correlations. For Eqs. (20) and (22), the major points are located within the relative deviation limit of ± 15%, while for Eq. (21), all the data points fall within the relative deviation limit of ± 20%. Comparison results indicate that the correlations can be used to understand the heat transfer upstream and downstream of partial blockages. Furthermore, numerical investigations and qualitative analyses of the effect of spare protrusions on the local heat transfer in the wake area are performed. These spare protrusions lead to local heat transfer deterioration in the wake zone; notably, the spacing between these protrusions does not have a significant influence on the augmentation of the heat transfer downstream.

Microfluidic biochip platform sensitized by AgNPs for SERS based rapid detection of uric acid

Herein, a novel microfluidic-biochip enabled with surface enhanced Raman spectroscopy (SERS) as a readout has been demonstrated for uric acid (UA) detection as point-of care (POC) device. Three different biochip designs (D1, D2 and D3) containing pillars in a microchannel with different bending ratios were conceived and optimized for various mixing parameters using a multiphysics simulation tool. The microchannel, integrated with pillars, provide pressure perturbation, sharp corners, and variation in bending ratio improves phase shift and mixing index. Subsequently the microfluidic-biochips were fabricated by a combination of photo-and soft-lithography, and bonding strength between two Polydimethylsiloxane substrates were found stable up to a flow rate of 1.8 ml min−1. Further to realize SERS activity in the microfluidic-biochip, cubic shape silver nanoparticles (AgNPs), with an average size ∼68 nm, were synthesized using poly-ol method. The SERS activity was optimized by simultaneously flowing AgNPs and crystal violet (CV) dye of 10−6M, with double inlet in the reservoir and highest sensitivity was achieved in the D3 biochip. Further, D3 biochip was employed for detection of extended concentrations of CV and UA. The enhancement factor limit of detection and relative standard deviation was found to be 2 × 107, 8.9 × 10−11 and 2.7% respectively for CV and 3.1 × 103, 3.2 × 10−7 and 2.9% respectively for UA. Interference of UA with lactic acid has been tested and device was able to detect signature peaks of both biomarkers up to 50 × 10−9 M concentration. Thus, the developed microfluidic-biochip device has potential to be used in a POC setting for onsite detection of biomarkers.

Dispersive solid phase extraction of several pesticides from fruit juices using a hydrophobic metal organic framework prior to HPLC-MS/MS determination

A metal organic framework (MOF)-based dispersive solid phase extraction procedure was introduced using a hydrophobic sorbent for the extraction of multi class pesticides from fruit juice samples prior to their determination by high performance liquid chromatography-tandem mass spectrometry. For this purpose, NH2-UiO-66(Zr) MOF was synthesized by a hydrothermal approach. Then the sorbent was silylated and used in the extraction procedure. The extraction procedure was done by using 7 mg of the sorbent from 5 mL of a sample solution containing the analytes. After that, the extracted analytes were eluted and preconcentrated by vaporizing the elution solvent. The method was linear within the range of 0.29–500 ng mL−1. The limits of detection, intra- and inter-day relative standard deviations, and extraction recoveries were in the ranges of 0.02–0.1 ng mL−1, 2.9–8.8%, 6.8–14.4%, and 74–89%, respectively. Performing the method on the selected samples showed that they were free of the analytes. This method can help to monitor the studied pesticides in juice samples as well as improving the safety of foods.

Evaluation of the repeatability of optical coherence tomography in patients with age-related cataract associated with dry eye.

To assess the repeatability of a new optical biometer (OA-2000, Tomey, Japan) based on swept-source optical coherence tomography (SS-OCT) and Placido-disk topography in dry eyes with cataracts. A cross-sectional study was performed. Two hundred sixteen eyes of 216 cataract patients were enrolled in our hospital from March 2020 to December 2020. According to the subjective symptoms and objective examination of dry eye, the patients were assigned to dry eye group and non-dry eye group. Axial length (AL), keratometry readings (K), lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT) and white-to-white (WTW) distance were measured by one skilled operator. The repeatability of each parameter based on within-subject standard deviation (Sw), repeatability limit of standard deviation (2.77Sw), coefficient of variation (CoV) and intra-class correlation coefficient (ICC) was evaluated. There was no significant difference in age and gender between the two groups. NiaBUT and NifBUT in the dry eye group were significantly lower than those in the non-dry eye group (p < 0.05). The ICC mean values of AL, K1, K2, Km, ACD, LT and CCT were all greater than 0.960, except WTW. In the dry eye group, except CCT and WTW, the Sw scores for other biometric parameters were lower than 0.201, 2.77Sw scores were lower than 0.557, CoV(%) was less than 1%, and ICC mean values were greater than 0.964. Among them, the Sw scores for AL, LT and ACD were lower than 0.035, the 2.77Sw scores were lower than 0.097, and the ICC mean values are greater than 0.990. The ocular biological parameters measured by SS-OCT have good repeatability for age-related cataract patients with dry eyes, in which the AL, LT and ACD are the highest repeatable. However, more attention should be paid for WTW in clinical application since repeatability influence.

Supramolecular solvent-based liquid phase extraction of antimony prior to spectrophotometric quantification.

Antimony (Sb) is highly hazardous to human health even in minute concentration. Therefore, its accurate and precise determination in the real environmental samples is of immense importance. In this work for the first time, UV-Vis spectrophotometric method was developed for the quantification of Sb(III) from water samples using supramolecular solvent (undecanol-tetrahydrofuran)-based extraction. The maximum absorption wavelength for antomony-diathizone complex was found to be 590nm having molar absorptivity of 3.1 × 104 L.mol.cm-1. Factors affecting extraction efficiency like solution sample volume, amount of chelating agent, pH, matrix effect, and type and volume of supramolecular solvent were determined and optimized. Analytical parameters like limit of detection (0.19µg L-1), limit of quantification (0.62µg L-1), pre-concentration factor (15), enhancement factor (15), and relative standard deviation for 8 successive analysis (0.8%) were calculated under optimized experimental conditions. The method was applied to real water samples like tap water of laboratory, waste water from Kohat hospitals, and dam water (Tanda dam Kohat) with quantitative addition recovery (94-100%).

Influence of distance from lens to sample surface on spectral sensitivity of femtosecond laser-induced breakdown spectroscopy with NaCl water film

Increasing the emission intensity of laser-induced breakdown spectroscopy (LIBS) is an effective way to improve the sensitivity of LIBS technology to elements analysis in liquid samples. In this work, the influence of the distance from lens to sample surface (DFLS) on the spectral emission of femtosecond laser-induced plasma of NaCl water film was studied by measuring Na atomic line. The results showed that the emission intensity of the spectral line presented the phenomenon of double peaks with an increase in the DFLS. The position for the highest spectral intensity was not geometric focal point of focusing lens, but was located in front of the geometric focal point. In addition, we carried out quantitative analysis on Na element with different concentrations, showing a calibration curve of Na element, and calculating limit of detection (LOD) and relative standard deviation (RSD) for different DFLSs. Subsequently, the changes in the LOD and RSD with the DFLS are discussed. With the increase of the DFLS, the LOD and RSD were greatly reduced. At the DFLS of 99.0 mm, the line intensity was highest, and the LOD and RSD were better. Therefore, it can be confirmed that femtosecond LIBS of water film can be optimized by changing the DFLS, the experiment shows great potential in real-time water quality monitoring.

Global and local aspects of world energy consumption: forecast and risks

The purpose of this study is to form a forecast of energy consumption at the global level in the long term, taking into account sectoral changes and the identification of possible deviation limits. Projections of total energy consumption at the global level, as well as by sector, were based on correlation analysis, autoregressive modelling and cluster analysis. The scientific contribution of this study is the formed forecast of energy consumption by regions and sectors until 2050, which is supplemented by clustering. Based on the developed forecasts of global energy consumption with a geographical distribution, the simulated results show that there is a slight increase in energy consumption in Europe compared to the other regions under study. The most significant increase in energy consumption is predicted in the Middle East. The study indicates the risk of exceeding the volume of energy consumption compared to the forecasts of international organisations, which were formed in previous years. The clustering showed the possible stratification of the world community in the context of energy consumption, which signals the migration of values of countries in the context of energy supply and increasing sustainability of the external environment.

Highly fluorinated magnetic covalent organic framework for efficient adsorption and sensitive detection of microcystin toxin in aqueous samples

The effective adsorption and sensitive determination of microcystin-LR (MC-LR) are crucial for the environment and human health. In this work, a highly fluorinated magnetic covalent organic framework (denoted as Fe3O4@TabTfa-F4) was synthesized through a simple strategy. The morphology and structure of the as-prepared Fe3O4@TabTfa-F4 were investigated and Fe3O4@TabTfa-F4 showed that it had a high specific surface area (442.3 m² g−1), high fluorine content (6.0%), large pore volume (0.255 cm³ g−1), and strong magnetic responses (31.0 emu g−1). The new sorbent Fe3O4@TabTfa-F4 was applied for MC-LR adsorption. The adsorption behavior was investigated, and the results followed pseudo-second-order kinetics and the Langmuir adsorption model. The excellent adsorption capacities for MC-LR (Qmax = 495.1 mg g−1) may be due to the formation of numerous hydrogen bonds, hydrophobic interaction, and π-π stacking interaction between MC-LR and Fe3O4@TabTfa-F4. Afterward, Fe3O4@TabTfa-F4 was used to extract MC-LR from aqueous samples, followed by high-performance liquid chromatography incorporated with UV spectroscopy. The major parameters that influenced the extraction performance were investigated. The developed method exhibited good linearity in the range of 0.25–20 ng L−1. Under the optimum conditions, limits of detection (S/N=3), limits of quantitation (S/N=10), enrichment factor and relative standard deviation were calculated to be 0.041 ng mL−1, 0.13 ng mL−1, 425, and 9.6%, respectively. The spiked recoveries ranged within 75.3%–108.6%. These findings indicate that Fe3O4@TabTfa-F4 has potential application to the adsorption and sensitive detection of MC-LR from aqueous samples.

Three-muscle surgery for large-angle esotropia in chronic sixth nerve palsy: comparison of two approaches

AimsTo report the effect of two three-muscle surgeries, inferior rectus belly transposition plus augmented superior rectus transposition plus medial rectus recession (ISM) and modified vertical rectus belly transposition plus medial...

Experimental Investigation of Sensorless Tension Control System for Textile Processes

Sensorless tension control system is investigated for textile processes and machines in this paper. A prototype unit unit was designed and manufactured for this aim. Prototype unit consisted of winding and unwinding warp beams driven by a servomotor and an induction motor. Warp tension was measured by load cells for evaluating the sensorless tension control system performance. Diameters of winding and unwinding warp beams were measured by laser sensors. Wound warp length was measured by an incremental encoder fitted to the shaft of a cylinder rotated by warp yarns. Number of beam rotations of warp beams were measured by separate inductive switches. A software program was developed in LabVIEW to implemet sensorless tension control algorithms and record the performance data. Results showed that the desired tension can be kept constant within 5% deviation limits by the servomotor torque control.

Investigation of IDEAL-CT Device Equivalence: Are All Devices Equal?

The IDEAL-CT (InDirect tEnsile AsphaLt Cracking Test) has rapidly become a popular cracking test for asphalt mixture acceptance. There have been several studies conducted to ensure this test is sufficient and acceptable for mixture acceptance purposes with respect to testing variability and the test’s ability to detect mixture quality improvements. A potential source of testing variability yet to be comprehensively studied is the variability introduced between testing devices. This paper provides a case study for the potential CTIndex variability, which can be attributed to the test device and the impact this has on determining whether devices are equivalent. The two one-sided tests (TOST) equivalence test, applied to this study, is a more appropriate statistical test to determine device equivalence when compared with typical hypothesis tests like analysis of variance. The TOST requires the user to have an understanding of an acceptable limit of deviation between two devices to determine both the statistical and practical equivalence between devices. This paper details the equivalence testing of 100 unique device-to-device comparisons and provides an example of the importance of using an appropriate number of samples to set achievable limits for accepting device equivalency. A relatively simple approach to assessing equivalence is recommended to IDEAL-CT users in situations in which device-to-device comparisons have real-world consequences. Finally, guidance is provided for selecting a minimum number of samples required to adequately test for device-to-device equivalence.

Modified method for the determination of cobalt (II) and copper (II) ions by adopting schiff base complexes in water of Shatt Al-Arab river

A new method of complex formation between cobalt or copper ions and Schiff Base (derived from Schiff Base of salicyldehyde and amino acids) was adopted for the determination of cobalt and copper ions in water samples of Shatt Al-Arab River. For water sampling three stations along Shatt Al-Arab River were selected as follows: 1) discharging point in Shatt Al-Arab from Basrah paper and mill industries, 2) Karmatt Ali Bridge, and 3) Siba downstream to the southern region of Shatt Al-Arab river. After the formation of a complex with Schiff Base, Cobalt and Copper in the water of Shatt Al-Arab were determined spectrophotometricaly at wave length of 270 nm and 295 nm respectively. It is found that cobalt concentrations were (0.152, 0.174, 0.165) mg.l-1 and copper concentrations were (0.014, 0.021, 0.023) mg.l-1 in stations 1, 2 and 3, respectively. The method is reliable with sensitivity, accuracy, standard deviation and detection limit of (0.0235 gm.cm.l-1, 3.05×10-6, 0.00184, 0.52×10-7) for cobalt complex and (0.0135 gm.cm.l-1, 3.31×10-6, 0.00215, 0.6×10-8) for copper complex, respectively.&#x0D;

Методика подготовки экспериментальных данных для информационно-интеллектуальной системы проектирования сетей лесовозных дорог

The article describes a technique for obtaining experimental data for the purpose of optimal distribution of the forest transport network on a specific terrain model. Particular attention was paid to the issue of the operability of primary forest transport routes, in particular, the requirements for the strength of trunk lines, which is of fundamental importance when establishing the optimal distance between long-term roads. The operability of the trunk lines was experimentally investigated, while the scheme of the movement of tractors along the ring was used. Based on experimental data, certain values of track depth, relative humidity, density and the number of impacts depending on the number of passes were obtained. In the course of the experimental study, functional dependences of the increase in the depth of the track on the number of passages were established and calculated, taking into account the physical and mechanical properties of forest soils. During the tests, some fundamental differences were recorded in the process of track formation during the movement of wheeled and tracked tractors. It is important for the development of measures to reduce the seasonality of forest transport, especially during the autumn-spring thaw. Comparative tests of tracked and wheeled tractors when they move along a reinforced track have shown that a reinforced track when moving a wheeled tractor is able to withstand a significantly greater number of passes than when moving a tracked tractor. For the statistical evaluation of the experiments carried out, it was determined what errors could be caused by replacing the parameter with its point estimate. Analysis of statistical processing of the observation results showed that all the series, as a rule, correspond to the law of normal definition, which is determined by the ratio of the symmetry and kurtosis indicators to their average errors. These relations are determined within the limits of permissible deviations, therefore, asymmetry and kurtosis in this case do not matter significantly.

Event‐triggered H∞$\mathcal {H}_\infty$ synchronization of directed and switched coupled stochastic delayed neural networks with multi‐weights

This essay is devoted to studying H ∞ $\mathcal {H}_\infty$ synchronization problem of directed and switched coupled stochastic delayed neural networks with multi-weights (SCSDNNMWs) via designing a novel event-triggered protocol. The proposed model is based on stochastic delayed neural network with directed coupling, and multiple coupling matrices with switching express intricate and changing communication channels. Since the external disturbances are likely to cause network topologies change, fixed and accurate values of coupling matrices are difficult to obtain, while the above model has more advantages of characterizing this real network. Besides, zero eigenvalue of different coupling matrices are represented by the corresponding normalized left eigenvectors (NLEVec), which is hard to establish yet especially when designing necessary Lyapunov functions. The authors' essay deduces that if the Chebyshev distance among NLEVec of multiple coupling matrices is less than a permissible deviation limit based on a weighted set of these NLEVec, then several event-triggered H ∞ $\mathcal {H}_\infty$ synchronization and synchronization criteria are established. The effectiveness of these results are verified by several given examples.