Classical Procedures Research Articles

Primary bone graft stability after Latarjet surgery: biomechanical evaluation of a fixation technique with metal-free all-suture cerclage vs. cortical screws

To reduce hardware-related complications in coracoid graft fixation to the anterior aspect of the glenoid, a metal-free Latarjet technique was recently introduced. The aim of this study was to compare the primary stability of a classic Latarjet procedure with two metal screws to a novel metal-free, all-suture cerclage method. It is hypothesized that fixation of the coracoid graft with two malleolar screws provides higher primary stability compared to an all-suture cerclage technique. This biomechanical in-vitro study was conducted on 12 fresh-frozen cadaveric shoulders (six matched pairs) with a mean donor age of 80 years (range, 67-89). Coracoid graft fixation was performed using a new all-suture cerclage technique (group A) or a classic Latarjet technique with two 4.5 mm malleolar screws (group B). The conjoint tendon was loaded with a static force of 10 N to simulate the sling effect. Graft loading with a probe head consisted of six ascending load levels (1. 10-50N, 2. 10-100N, 3. 10-150N, 4. 10-200N, 5. 10-250N, 6. 10-300N) with 100 cycles each at one Hertz. Relative motion of the bone graft to the glenoid was measured using an optic three-dimensional system. While loading the conjoint tendon with 10 N no difference in mean displacement of the bone-graft was found between both groups (p=0.144). During cyclic loading a significant difference in relative displacement for both groups was already detected in load level one (Group A: 2398,8 μm vs. Group B: 125,7 μm; p=0.024) and this trend continued with the following load levels (p<0.05). The study demonstrated that the innovative metal-free, all-suture cerclage fixation technique results in higher micromotion than the classic coracoid graft fixation with two malleolar screws. According to the present biomechanical investigation, shoulders treated with a metal-free all-suture cerclage technique might need adapted rehabilitation protocols to protect the construct and allow for graft healing.

Stochastic virtual element methods for uncertainty propagation of stochastic linear elasticity

This paper presents stochastic virtual element methods for propagating uncertainty in linear elastic stochastic problems. We first derive stochastic virtual element equations for 2D and 3D linear elastic problems that may involve uncertainties in material properties, external forces, boundary conditions, etc. A stochastic virtual element space that couples the deterministic virtual element space and the stochastic space is constructed for this purpose and used to approximate the unknown stochastic solution. Two numerical frameworks are then developed to solve the derived stochastic virtual element equations, including a Polynomial Chaos approximation based approach and a weakly intrusive approximation based approach. In the Polynomial Chaos based framework, the stochastic solution is approximated using the Polynomial Chaos basis and solved via an augmented deterministic virtual element equation that is generated by applying the stochastic Galerkin procedure to the original stochastic virtual element equation. In the weakly intrusive approximation based framework, the stochastic solution is approximated by a summation of a set of products of random variables and deterministic vectors, where the deterministic vectors are solved via converting the original stochastic problem to deterministic virtual element equations by the stochastic Galerkin approach, and the random variables are solved via converting the original stochastic problem to one-dimensional stochastic algebraic equations by the classical Galerkin procedure. This method avoids the curse of dimensionality in high-dimensional stochastic problems successfully since all random inputs are embedded into one-dimensional stochastic algebraic equations whose computational effort weakly depends on the stochastic dimension. Numerical results on 2D and 3D problems with low- and high-dimensional random inputs demonstrate the good performance of the proposed methods.

Development and validation of analytical procedure for analysis of Amoxiciline, Metronidazole and Omeprazole, used as anti- Helicobacter pylori agents alone and in mixture

Background: The contemporary treatment of ulcerogenic diseases and gastroesophageal reflux disease is related usually to application of a combination of imidazole-based antibacterial, antibiotic and proton pump inhibitor. In the current study, the three most common representatives Amoxicilline (AMO), Metronidazole (MET) and Omeprazole (OME), respectively, are subjected to analysis through classical analytical procedure, providing high level accuracy, sensitivity and good separation abilities. As such a UV/VIS method was applied as a well known identification and quantitation technique for analyses in various samples. Furthermore, this technique is known to be a good detection method in combination with chromatographic systems. Purpose: A simple, specific, accurate and precise reverse phase-high performance liquid chromatographic method has been developed for the simultaneous determination of Amoxicillin Trihydrate (AMO), Metronidazole (MET) and Omeprazole (OME) in synthetic mixture. Materials and methods: Some important parameters like pH of the mobile phase, concentration of the acid or buffer solution, percentage and type of the organic modifier, etc. were tested for a good chromatographic separation. The sample was analyzed using a mobile phase of Acetonitrile: Phosphate buffer (pH=7.6±0.1) (40:60 v/v). The flow rate was 1.0 mL/ min with detection at 280 nm. Results: The retention time for AMO, MET and OME was found to be 1.67, 2.86 and 5.99 min respectively, and the recoveries in the synthetic mixture were between 98 and 102%. The validated method was linear over the concentration range of 25 to 200 μg/mL for AMO, 12.5 to 100 μg/mL for MET and 5–40 µg/mL for OME, with a correlation coefficient &amp;gt; 0.999. Conclusion: The developed method has been validated in accordance with the International Conference on Harmonization (ICH) guidelines and showed excellent linearity, accuracy, precision, specificity, robustness, as well as system suitability results within the acceptance criteria.

Inferior displacement of the lateral rectus muscle insertion in exotropia with mild V-pattern or vertical deviation.

To describe clinical features and intraoperative findings of the patients with exotropia who presented mild V-pattern or vertical deviation, and to investigate the surgical outcomes of anatomical relocation of inferiorly displaced lateral rectus (LR) muscle insertion. Detailed ophthalmological evaluations were obtained in 42 consecutive patients, and the horizontal rectus muscle insertions were detected intraoperatively. The displaced insertion of LR muscle was corrected accompanied with classic recession-resection procedure. The inferiorly displaced LR muscle insertions were detected in 19 patients (Group A), while the remaining 23 patients (Group B) had normal insertions. The mean distance of displaced insertion from the normal position was 2.92 ± 1.05 mm (range: 1.0-4.0). Mild V-pattern was more common in Group A (78.9%, 15/19) than Group B (47.8%, 11/23), and the magnitude of V-pattern in Group A (6.16 ± 3.91 PD) was also greater than Group B (3.43 ± 3.92 PD). The fundus extorsions of the affected eyes (9.68 ± 4.77 °) were greater than the contralateral eyes (5.91 ± 5.82 °) in Group A. At the 2 months follow-up, mild V-pattern and mild vertical deviation were corrected by upward transposition. The significant correlations were identified between the pre-operative misalignments and the amounts of misalignments correction. Nearly half of the cases with mild V-pattern or vertical deviation resulted from the inferiorly displaced LR muscle insertion, so the intraoperative exploration of the LR muscle insertion is strongly suggested. Upward transposition may effectively correct both the mild V-pattern and vertical deviation.

Diagnosis and Treatment of Double Thyroglossal Duct Cyst.

This retrospective study aimed to investigate clinical diagnostic and management characteristics of double thyroglossal duct cyst (TDC) cases. Seventy-eight patients diagnosed with TDCs who were admitted to the inpatient ward of the Department of Otolaryngology, Dalian Central Municipal Hospital from June 2008 to October 2021 were included in the study. Ultimately, 67 of these patients were diagnosed with single TDCs and 11 patients with double TDCs. Each patient underwent computed tomography and color doppler ultrasound imaging of their neck masses, thyroid color doppler ultrasound imaging, and surgical cyst removal through the classic Sistrunk procedure. All surgically excised specimens were sent to the pathology lab for examination and were confirmed to contain TDCs. Two of the 67 patients with single TDCs experienced postoperative complications related to infections within the operative area, whereas no patients with double TDCs experienced postoperative infection, excessive bleeding, or other surgical complications. All cases were followed up for 1 to 3 years after surgery with no cyst recurrence observed. Double TDCs may present on physical examination as unilateral neck masses that interfere with tongue extension and movement and swallowing that can be identified using imaging methods. Correct clinical diagnosis and complete surgical removal of cysts are key measures for ensuring successful treatment outcomes for patients with TDCs.

Tube-first Technique as a Conduit for Easy and Fast Nasal Fiberoptic Intubation

Background: Classical nasal fiberoptic bronchoscope intubation may be a challenging and lengthy procedure with a 1-10% failure rate. Objectives: This study aimed to compare among patients with difficult airway intubation undergoing general anesthesia, the safety, and efficacy of Tube-First (TF) nasal fiberoptic bronchoscope intubation against the Classic (CL) procedure. Methods: This single-blinded, parallel-group, randomized trial enrolled 40 adult patients with known difficult airways and scheduled for surgery under general anesthesia. The patients were randomly allocated into two (n=20 each) patient groups. In the CL group, the endotracheal tube and fiberoptic bronchoscope were inserted together through the nostril; in the TF group, the endotracheal tube insertion preceded the fiberoptic bronchoscope. In both groups, the bronchoscope was used to visualize the vocal cords and removed after ensuring the endotracheal tube position. The primary (efficacy) outcomes were the time elapsing from the bronchoscope insertion and visualizing the vocal cords (T1) and the time elapsing from the bronchoscope advancing initiation to its removal (T2). The secondary (safety) outcomes included oxygen saturation and hemodynamic parameters during the procedure. Results: The TF group showed a significant T1 and T2 mean reduction compared to those of the CL group (37.15 ± 3.87 and 64.25 ± 8.28 vs. 55.05±4.52 and 88.25±5.49 seconds, respectively; p &lt; 0.0001). The oxygen saturation was comparable in both groups with no desaturation (SpO2 &lt; 90%) cases. The heart rate and mean arterial blood pressure changes were significantly lower in the TF group compared to the CL group. Conclusion: Among patients with difficult airway intubation undergoing general anesthesia, we found the Tube-First intubation approach was quicker and safer compared to the classical intubation technique.

Nonlinear Aerodynamic Global Model Identification using Gram-schmidt Orthogonalization

This paper discusses a simple technique to identify global models for nonlinear aerodynamic force and moment coefficients of aircraft using multivariate orthogonal functions. Classical Gram-Schmidt procedure and Predicted Squared Error metric are used to generate the orthogonal functions. Global models for the F-16 aircraft are identified from a simplified subsonic (Mach &lt; 0.6) wind tunnel database available in open literature. The identified models are compared with those found in literature for the same wind tunnel database and conclusions are drawn.

Optimal Control of a Viscous Two-Field Damage Model with Fatigue

Motivated by fatigue damage models, this paper addresses optimal control problems governed by a non-smooth system featuring two non-differentiable mappings. This consists of a coupling between a doubly non-smooth history-dependent evolution and an elliptic PDE. After proving the directional differentiability of the associated solution mapping, an optimality system which is stronger than the one obtained by classical smoothening procedures is derived. If one of the non-differentiable mappings becomes smooth, the optimality conditions are of strong stationary type, i.e., equivalent to the primal necessary optimality condition.

A Relative Field Antenna Calibration Method Designed for Low-Cost GNSS Antennas by Exploiting Triple-Differenced Measurements

Performing the high-precision Global Navigation Satellite System (GNSS) applications with low-cost antennas is an up-and-coming research field. However, the antenna-induced phase biases, i.e., phase center corrections (PCCs), of the low-cost antennas can be up to centimeters and need to be calibrated in advance. The relative field antenna calibration method is easy to conduct, but the classical procedure entails integer ambiguity resolution, which may face the problem of low success rate under the centimeter-level PCCs. In this contribution, we designed a relative field calibration method suitable for the low-cost GNSS antennas. The triple-differencing operations were utilized to eliminate the carrier-phase ambiguities and then construct PCC measurements; the time-differencing interval was set to a relatively long time span, such as one hour, and the reference satellite was selected according to the angular distance it passed over during a time-differencing interval. To reduce the effect of significant triple-differencing noise, a weight setting method based on the area of a spherical quadrilateral was proposed for the spherical harmonics fitting process. The duration of the data collection with respect to GPS and BDS was discussed. The performance of the proposed method was assessed with real GPS and BDS observations and a variety of simulated phase patterns, showing that calibration results could be obtained with millimeter-level accuracy. The impact of cycle slip and elevation mask angle on the calibration results was also analyzed.

Surgical management of burn injury patients : Comments on the guidelines on treatment of thermal injuries in adults

The treatment of burn injury patients is aunique challenge for clinicians. The extent of thermal injuries ranges from very small burns to life-threatening burn injuries. Insufficient treatment can result in a substantial impairment in the quality of life. In order to avoid such sequelae a targeted treatment must be carried out. A precise diagnosis determines the necessary treatment. Superficial second-degree burns (2a) not involving the face, hand or joints with atotal body surface area smaller than 10% can usually be treated with modern wound dressings in an outpatient setting. Deep second-degree burns (2b) are an indication for debridement. In addition to the classical surgical procedures with tangential excision, enzymatic debridement can also be employed. Similarly, indeterminate burns (2a/2b) are also considered to be an indication for enzymatic debridement. Third-degree burns are treated with early debridement and skin grafting. These patients can also benefit from special dermal replacement procedures for an improvement of the functional and esthetic results. Due to the long-term visible sequelae of burns, aftercare of these patients is indicated.

Innovative Equivalent Elastic Modulus Based Stress Calculation Methodology for Reinforced Concrete Columns

The combination of linearity and elasticity assumptions provides classical calculation procedures for the reinforced concrete (RC) columns and beams against internal and external seismic loads. In these calculation procedures, the elasticity modulus of the concrete is taken into account by ignoring the steel reinforcement due to its small area percentage in the total cross-section area. This paper presents an innovative column stress calculation procedure considering the concrete–steel composition as the equivalent elastic modulus based on the classical Hooke’s Law. This methodology takes into consideration also the elastic modulus of the steel, providing a reduction in the factor of safety. The application of the proposed method is presented for a series of RC column cross-section areas. It is observed that the proposed methodology leads to elastic modulus improvement of 6% to 27% compared to conventional calculations. The necessary flow chart for the execution of the proposed process steps and accordingly developed MATLAB program are provided for the application.

Continuous finite-time fuzzy control of mechanical systems via non-Lipschitz membership functions

This document presents a method to construct continuous fuzzy controllers that yield finite-time stability of the closed-loop system. The proposed approach allows the user to follow classical design procedures for fuzzy systems without using other finite-time techniques such as sliding modes. The finite-time stability property is a consequence of a special kind of input membership function of the fuzzy inference system.The continuity properties of the fuzzy inference system are studied. Sufficient conditions for the output of the fuzzy inference system to be Lipschitz continuous are stated.A comparison with the asymptotic counterpart of the controller is also presented. The results support the hypothesis that finite-time controllers provide improved robustness to the steady state response.

A classical first-order normalization procedure with $$\forall $$ and $$\exists $$ based on the Milne–Kürbis approach

A classical first-order normalization procedure with $$\forall $$ and $$\exists $$ based on the Milne–Kürbis approach

Current level of development and improvement of the design process for tool calibrations of CRP mills

The article presents the results of review analysis of publications of Russian and foreign authors (representatives of both new and established research teams), considering the directions of improvement of existing processes of cold rolling of pipes (CRP). It is shown that for the last decades a major part of studies is devoted to solving different design problems, including the improvement of power elements of electric drive and drive mechanisms, improving of electromechanical system of feeding and turning mechanisms, development of delivery tables structural design, tooth rack, etc. Less attention is paid to finite-element modeling of cold rolling process at tube mills. Separately, the issue of designing of technological tool calibrations of CRP mills has been analyzed. Currently main scientific and technical activities aimed at improving the software and methodological apparatus for designing gauges are focused on specifying individual parameters of already developed earlier classic design procedures and their implementation in various proprietary software products. Examples of modern calculation algorithms, design schemes and main characteristics (advantages and disadvantages, influence on quality indexes of pipes) of current stage of rolling mills technological tools calibrating are given. The functional and technical features of the software products used for this purpose are analyses and the current requirements for modern software are given. Based on the analysis, it is shown that maximum concentration of previously achieved results and their synergy with modern world research trends in calculation methods development of tool profiling in CRP mill is a timely and strategically important task for the domestic pipe industry.

Product of Spacing Estimation of Stress–Strength Reliability for Alpha Power Exponential Progressively Type-II Censored Data

The present study focuses on estimating the stress–strength parameter when the parent distribution is the alpha power exponential model and the available data are progressively Type-II censored. As a starting point, the usual maximum likelihood approach is applied to obtain point and interval estimates of the model parameters, as well as the stress–strength parameter. Another competing strategy employed in this paper is the maximum product of spacing method, which may be thought of as a rival to the maximum likelihood method. The product of spacing approach is used to obtain point and interval estimates for the various parameters. The asymptotic properties of both methods are used to obtain interval estimates of the model parameter and the stress–strength parameter, and the variance of the stress–strength parameter is approximated using the well-known delta method. Two parametric bootstrap confidence intervals are provided based on the suggested classical estimation procedures. A simulation study is also used to assess the performance of various point and interval estimations. For illustrative purposes, the proposed methods are applied to two real data sets, one for the kidney patients’ recurrence times to infection and the other for breaking the strength of jute fibers.

Null controllability of a retarded population dynamics model with interior degeneracy

In this work, we establish a null controllability property of a dispersive age‐structured population dynamics model with finite‐time delay on the mortality rate term. We assume that the dispersion term includes an interior degeneracy satisfying some suitable assumptions. To achieve our main results, we act according to the classical procedure, which is the Carleman estimates of a suitable adjoint system, and then its associated observability inequality. It is well known that the basis of Carleman's estimates is an adjusted weight function and one of the originalities of our article is the expression of the function as a function of age and time variables.

An Improved Inferential Procedure to Evaluate Item Discriminations in a Conditional Maximum Likelihood Framework

A modified and improved inductive inferential approach to evaluate item discriminations in a conditional maximum likelihood and Rasch modeling framework is suggested. The new approach involves the derivation of four hypothesis tests. It implies a linear restriction of the assumed set of probability distributions in the classical approach that represents scenarios of different item discriminations in a straightforward and efficient manner. Its improvement is discussed, compared to classical procedures (tests and information criteria), and illustrated in Monte Carlo experiments as well as real data examples from educational research. The results show an improvement of power of the modified tests of up to 0.3.

Synthetic Data Generation for Morphological Analyses of Histopathology Images with Deep Learning Models

In this study, we introduce a new synthetic data generation procedure for augmentation of histopathology image data. This is an extension to our previous research in which we proved the possibility to apply deep learning models for morphological analysis of tumor cells, trained on synthetic data only. The medical problem considered is related to the Ki-67 protein proliferation index calculation. We focused on the problem of cell counting in cell conglomerates, which are considered as structures composed of overlapping tumor cells. The lack of large and standardized data sets is a critical problem in medical image classification. Classical augmentation procedures are not sufficient. Therefore, in this research, we expanded our previous augmentation approach for histopathology images and we proved the possibility to apply it for a cell-counting problem.

Modified Endoscopic Distal Soft Tissue Procedure With Medial Metatarsosesamoid Ligament and Intermetatarsal Ligament Augmentation

Hallux valgus is one of the most common foot and ankle conditions faced by orthopaedic surgeons. Surgical correction of hallux valgus is frequently indicated for symptomatic deformity. Recently, the endoscopic technique of hallux valgus correction has been reported, which is basically an endoscopic approach to the classic distal soft tissue procedure. In this technical note, the technical details of the modified endoscopic distal soft tissue procedure with medial metatarsosesamoid ligament and intermetatarsal ligament augmentation is described. In this modified technique, the intact intermetatarsal ligament, plantar capsule of the first metatarsophalangeal joint (including the sesamoid apparatus), and medial metatarsosesamoid ligament form a soft tissue envelop that can wrap around the first metatarsal head to stabilize the first metatarsal in the reduced position.

Synchrotron-based FTIR microspectroscopy reveals DNA methylation profile in DNA-HALO structure

Fourier transform infrared (FTIR) spectroscopy is a rapid, non-destructive and label-free technique for identifying subtle changes in all bio-macromolecules, and has been used as a method of choice for studying DNA conformation, secondary DNA structure transition and DNA damage. In addition, the specific level of chromatin complexity is introduced via epigenetic modifications forcing the technological upgrade in the analysis of such an intricacy. As the most studied epigenetic mechanism, DNA methylation is a major regulator of transcriptional activity, involved in the suppression of a broad spectrum of genes and its deregulation is involved in all non-communicable diseases. The present study was designed to explore the use of synchrotron-based FTIR analysis to monitor the subtle changes in molecule bases regarding the DNA methylation status of cytosine in the whole genome. In order to reveal the conformation-related best sample for FTIR-based DNA methylation analysis in situ, we used methodology for nuclear HALO preparations and slightly modified it to isolated DNA in HALO formations. Nuclear DNA-HALOs represent samples with preserved higher-order chromatin structure liberated of any protein residues that are closer to native DNA conformation than genomic DNA (gDNA) isolated by the standard batch procedure. Using FTIR spectroscopy we analyzed the DNA methylation profile of isolated gDNA and compared it with the DNA-HALOs. This study demonstrated the potential of FTIR microspectroscopy to detect DNA methylation marks in analyzed DNA-HALO specimens more precisely in comparison with classical DNA extraction procedures that yield unstructured whole genomic DNA. In addition, we used different cell types to assess their global DNA methylation profile, as well as defined specific infrared peaks that can be used for screening DNA methylation.