Recognizing the better autograft and the factors influencing outcomes of revision anterior cruciate ligament reconstruction

Objectives: The outcome of revision anterior cruciate ligament reconstruction (ACLR) is inferior to that of the primary reconstruction and is influenced by multiple factors. The purpose of this study was to identify the better autograft suited for revision ACLR and to assess the factors influencing the outcome of revision. Methods: A total of 102 patients who underwent revision ACLR were enrolled in this study. The patients were grouped based on the type of autograft used for revision. The mechanism of injury and the cause of the primary ACLR failure, meniscal, and chondral status were noted. All patients’ Tegner Lysholm functional scores were assessed at 2 years of follow-up. Results: Almost 37.3% of the patients underwent revision ACLR with bone-patellar tendon bone, 41.3% with semitendinosus-gracilis, and 21.3% with quadriceps tendon autografts. The mean Tegner-Lysholm score was 85.4 ± 15.8, with the majority achieving good to excellent scores. Chondral defect of Grade 3/4 was associated with an inferior poorer functional outcome (P = 0.03). At a 2-year follow-up, the non-contact mechanism of primary ACLR failure was associated with worse scores compared to the contact mechanism of failure (P = 0.03). On comparison of Lysholm functional score between different autografts using the Kruskal-Wallis test, the p-value was insignificant (P = 0.9). Conclusion: Non-contact mechanism of primary ACLR failure and Grade 3/4 chondral defects was associated with a poorer functional outcome at 2 years post-revision ACLR. The overall functional outcome of revision ACLR was good to excellent in our Middle East Asian population, with no one autograft found to be superior to the other.

Interrelation of global changes in the planet's biosphere with the expansion of viruses and the COVID-19 pandemic

Epidemics of new, previously unknown human viral diseases have been occurring with increasing frequency in recent decades. The COVID-19 pandemic caused by the SARS-CoV-2 coronavirus has demonstrated humanity's unpreparedness for new challenges and a complete lack of understanding of the causes of viral aggression. An attempt to explain the catastrophic development of the pandemic by accidental transmission of the virus from an animal to a person does not seem convincing. The explosive development of the epidemic process in large ecosystems negates the existing ideas about the contact mechanism of pathogenic virus transmission from person to person. Probably, the causes of the pandemic are related to global changes in the biosphere of the planet. According to V. I. Vernadsky's theory, the biosphere consists of three main parts: plants, animals and microorganisms, the total mass of which is a constant value. In recent decades, the rate of destruction of forests as the main resource of the plant world has considerably increased. The number of wild animals has decreased and at the same time the human population has increased. The growing disproportions led to the expansion of viruses with a new vector from animals to humans. Global insight into the role of viruses in the biosphere of the planet leads to understanding of the COVID-19 pandemic causes. There is every reason to believe that viruses have wave properties, and are able to produce a magnetic field, stable coherent resonance systems and interact without the participation of biochemical transformations. The energy of the electromagnetic field can be high enough for non-contact infection and assembly of an active biological virus inside the human body. The physical theory of viruses significantly expands the existing understanding of the role of viruses in the biosphere of the planet and the causes of new viral infections.

Suppression of B-Cell Activation by Human Cord Blood-Derived Stem Cells (CB-SC) through the Galectin-9-Dependent Cell Contact Mechanism

Background: We developed the Stem Cell Educator therapy among multiple clinical trials based on the immune modulations of multipotent cord blood-derived stem cells (CB-SC) on different compartments of immune cells such as T cells and monocytes/macrophages in diabetes and other autoimmune diseases. However, the effects of CB-SC on the B cells remained unclear. To better understand the molecular mechanisms underlying the immune education of CB-SC, we explored the modulations of CB-SC on human B cells. Methods: CB-SC were isolated from human cord blood units and confirmed by flow cytometry with different markers for their purity. B cells were purified by using anti-CD19 immunomagnetic beads from human peripheral blood mononuclear cells (PBMC). Next, the activated B cells were treated in the presence or absence of coculture with CB-SC for 7 days before undergoing flow cytometry analysis of phenotypic change with different markers. RT-PCR was utilized to evaluate the levels of galectin expressions with or without treatment of activated B cells in order to find the key galectin contributing to the B-cell modulation. Results: Flow cytometry demonstrated that the proliferation of activated B cells was markedly suppressed in the presence of CB-SC, leading to the down-regulation of immunoglobulin productions from the activated B cells. Phenotypic analysis revealed that treatment with CB-SC increased the percentage of IgD+CD27- naive B cells, but decreased the percentage of IgD-CD27+ switched B cells. Transwell assay showed that the immune suppression of CB-SC on B cells was dependent on the manner of cell-cell contact via Gal-9 molecule, as confirmed by the blocking experiment with the anti-Gal-9 monoclonal antibody. Mechanistic studies demonstrated that both calcium levels of cytoplasm and mitochondria were down-regulated after the treatment with CB-SC, causing the decline of mitochondrial membrane potential in the activated B cells. Western blot exhibited that the levels of phosphorylated Akt and Erk1/2 signaling proteins in the activated B cells were also markedly reduced in the presence of CB-SC. Conclusions: CB-SC displayed multiple immune modulations on B cells through the Gal-9-mediated cell-cell contact mechanism and calcium flux/Akt/Erk1/2 signaling pathways. The data advances current understanding about the molecular mechanisms underlying the Stem Cell Educator therapy to treat autoimmune diseases in clinics.

Modeling and validation of preload force effect on characteristics of a V-shaped linear ultrasonic motor

The traditional dynamic models of linear ultrasonic motor (LUSM) do not consider the influences of the preload force and the roughness of the contact surface of stator/slider on the performance of the motor, which unable to effectively describe the dynamic behavior of the motor. In this paper, a dynamic model is established for a V-shaped LUSM considering the influence of the preload force and the roughness of the contact surface of stator/slider on the dynamic behavior of the motor. The contact mechanism of the stator/slider and the influence of preload force on the stator parameters are studied and analyzed. The effectiveness of the developed model is verified by comparing with the analytical model that ignored the effect of the preload force on the stator parameters. The experimental results shown that the developed model can accurately reflect the dynamic characteristics of the motor, and the model will be helpful for the function prediction and precise control of the motor.

Apical contacts stemming from incomplete delamination guide progenitor cell allocation through a dragging mechanism

The developmental strategies used by progenitor cells to allow a safe journey from their induction place towards the site of terminal differentiation are still poorly understood. Here, we uncovered a mechanism of progenitor cell allocation that stems from an incomplete process of epithelial delamination that allows progenitors to coordinate their movement with adjacent extra-embryonic tissues. Progenitors of the zebrafish laterality organ originate from the superficial epithelial enveloping layer by an apical constriction process of cell delamination. During this process, progenitors retain long-lasting apical contacts that enable the epithelial layer to pull a subset of progenitors on their way to the vegetal pole. The remaining delaminated cells follow the movement of apically attached progenitors by a protrusion-dependent cell-cell contact mechanism, avoiding sequestration by the adjacent endoderm, ensuring their collective fate and allocation at the site of differentiation. Thus, we reveal that incomplete delamination serves as a cellular platform for coordinated tissue movements during development.

Design of a novel tendon-driven manipulator structure based on monolithic compliant rolling-contact joint for minimally invasive surgery

Purpose Compliant mechanisms are commonly used in the design of manipulator and surgical robotic tools for minimally invasive surgery (MIS) thanks to their compactness, ability of miniaturization and lower part count. However, conventional compliant joint has higher internal stiffness, which limits the bending radius. To overcome this problem, a novel tendon-driven manipulator structure based on monolithic compliant rolling-contact joint (CRCJ) is proposed. Methods The proposed rolling-contact mechanism is used to prevent cable slack during actuation, which occurs in conventional compliant joint design. By means of selective laser sintering (SLS) technique, the CRCJ can be fabricated in a monolithic structure, thus granting the CRCJ both the advantages of compliant joints and rolling-contact mechanism. Simulations with nonlinear finite element analysis (FEA) and experiments were conducted to evaluate and compare the mechanical properties of the proposed CRCJ with conventional leaf-type compliant joint including the bending and compliant motion. Results Experimental results showed that the CRCJ has lower bending stiffness, higher maximum bending angle (over $$180^{\circ }$$ 180 ∘ ) and a higher compliance compared to conventional compliant hinges, which allows a larger workspace and reduces the possibility of tissue injury. Agreement was also found between the nonlinear FEA and experiments regarding the relation between actuation force and bending angle. A primary prototype of a 3-DOF handheld laparoscopic manipulator with a diameter of 7 mm was further developed. Conclusion A dexterous tendon-driven monolithic manipulator structure based on CRCJ for MIS is proposed. A preliminary prototype of a handheld laparoscopic manipulator demonstrates the capability of the CRCJ for steerable medical devices. However, design improvements based on FEA and application-orientated prototypes considering anatomical requirements still show room for improvements.

Effect Of Marketing Communication In Promoting Organizational Sales. A Case Study Of Lada Uzbekistan Company

The value of interaction cannot be overstated when analyzing variables that project a good relationship between companies and their future clients. A company's marketing contact mechanism must be regulated for both successful effectiveness and product promotion in order for it to survive in this fierce rivalry. In this paper, secondary data were used. The correlation coefficient was used to interpret the results, and the hypothesis was evaluated using the normal distribution. The review shows that the use of promotions as part of a blend has helped Lada Uzbekistan Company not only increase exposure but also sales; therefore, it is a worthy endeavor that should be made a central feature of the company's marketing policy. The recommendation for the Lada Uzbekistan Company is to review the various advertising mix components and choose those that can effectively produce product demand while still increasing sales in order to achieve corporate goals.

Epidemiology of Shoulder Instability in the National Football League

Background: Shoulder instability is a common and potentially debilitating injury among collision sport athletes that can lead to long-term damage of the glenohumeral joint. Limited data exist regarding instability among elite athletes in the National Football League (NFL). Purpose: To describe the epidemiology of shoulder instability in the NFL from 2012 through 2017. Study Design: Descriptive epidemiology study. Methods: The NFL’s injury database was reviewed for shoulder instability injuries resulting in missed time during the study inclusion dates. Injuries were classified by type and direction, as well as timing, setting, and mechanism. Median missed time was determined for the different types and directions of instability. Incidence rates for game-related injuries were calculated based on timing during the season and player position. Finally, the relationship between player position and instability direction was assessed. Results: During the 6-year study period, 355 players sustained 403 missed-time shoulder instability injuries. Most injuries occurred during games (65%) via a contact mechanism (85%). The overall incidence rate of game-related instability was 3.6 injuries per 100,000 player-plays and was highest during the preseason (4.9 per 100,000 player-plays). The defensive secondary position accounted for the most injuries, but quarterbacks had the highest incidence rate in games (5.5 per 100,000 player-plays). Excluding unspecified events (n = 128; 32%), 70% (n = 192) of injuries were subluxations and 30% (n = 83) were dislocations; 75% of dislocations were anterior, while subluxations were more evenly distributed between the anterior and posterior directions (45% vs 52%, respectively). Players missed substantially more time after dislocation compared with subluxation (median, 47 days vs 13 days, respectively). When instability direction was known, the majority of instability events among quarterbacks and offensive linemen were posterior (73% and 53%, respectively), while anterior instability was most common for all other positions. Conclusion: Shoulder instability is a common injury in the NFL and can result in considerable missed time. Dislocations occur less frequently than subluxations but lead to greater time lost. While most dislocations are anterior, more than half of subluxations are posterior, which is likely the result of repetitive microtrauma to the posterior capsulolabral complex sustained during sport-specific motions such as blocking. The risk of instability varies by player position, and position may also influence instability direction.