Defective Valve Research Articles

Varicose Veins: A Review and Management

Abstract: Twisted, swollen veins that are commonly found on the lower limbs can be deformative and incapacitating. Varicose vein prevalence varies. At least one-third of people are thought to have lower leg varicose veins. Family history, obesity, advanced age, pregnancy, and prolonged standing are risk factors. The pathogenesis includes weakening vascular walls, defective valves, and genetic factors. Treatment options for varicose veins include surgery, interventional therapy, and conservative measures like diet, lifestyle modifications, and hydrotherapy—all of which depend heavily on patient compliance to be effective. The symptoms, patient preferences, cost, and possible risks all influence the therapeutic selection. This review looks at varicose vein risk factors, symptoms, management (surgery and conservative measures), and complication avoidance

IMPLICATION OF LEECH THERAPY AND ASBAB-E-SITTA ZAROORIYAH IN THE PREVENTION AND TREATMENT OF VARICOSE VEINS: A COMPREHENSIVE REVIEW

Varicose veins are characterized by abnormally twisted, dilated superficial vessels that are caused by the inefficient or defective valves within the vein. It is currently a prevalent disease with the incidence varying globally between 10% and 60%. The Unani Medicine (also called Greco-Arab medicine) is the ancient system of medicine practiced all around the world. According to the Unani classical text, Leech therapy (Irsal-e-Alaq) is one of the most important regimenal therapy for the successful treatment and management of varicose vein and a unique combination of Asbab-e-Sitta Zarooriyah (Six essential factors) is involved in the prevention of this disease. The research studies have proved that medicinal leech therapy displays anticoagulant, antimicrobial, anti-inflammatory and analgesic effects. Leech saliva contains medicinally useful bioactive molecules like hirudin, histamine, etc. that shows anti-coagulant effect and hence improve microcirculation in diseases like varicose vein. Leech therapy is reliable, well tolerated, cost effective treatment that has the potential of preventing varicose vein complications. This review seeks to describe medicinal leech therapy, present therapeutic leech species, and highlight the processes by which leech saliva affects wound healing. Additionally, the review paper highlights the role of Asbab-e-Sitta Zarooriyah in prevention and control of varicose veins. Irregularity in diet and lifestyle may cause disturbance in normal body functioning, which may lead to lifestyle disorder that is a major risk factor thought to influence the susceptibility of varicose vein. The Unani System exerts a major influence on preventing the development of varicose vein by making modification in Asbab-e-Sitta Zarooriyah.

Anesthetic-Cardiological Complications in Aortic Valve Replacement

Aortic valve replacement (AVR) is a surgical procedure in which the defective valve is surgically removed and a new valve is implanted. The surgical technique is used when the aortic valve becomes stenotic or regurgitant, leading to decreased cardiac output and other life-threatening complications. AVR is performed under general anesthesia.

Application of PDCA Method in Improving the Quality of Valve Production

Plastic is one of the most widely used raw materials for a product. Human life cannot be separated from products or equipment made from plastic. Company X often has problems with the quality of the products produced, especially valve products as products that are produced every day. The corrective step used to assist Company X in improving the quality of valve products is the application of the PDCA method. PDCA method consists of the plan, do, check, and act stages. The proposed improvement design was carried out based on the results of data processing and obtained as many as 9 proposed improvements. In the do stage, implementation of the proposed improvements that have been designed is carried out, five proposed improvements can be implemented and the other four in the form of recommendations. Next is the check stage, which is the process of collecting data again on the results of the implementation of the proposed improvement. Based on the results of the check stage, a standardization process was carried out at the act stage to improve the performance of the proposed improvement and the quality of the valve product. Standardization is done by changing or improving the proposed improvements that have been implemented. Research has succeeded in reducing the number of defective valve products with the proportion of defects that were previously 1.16% to 0.57%.

Application of PDCA Method in Improving the Quality of Valve Production

Plastic is one of the most widely used raw materials for a product. Human life cannot be separated from products or equipment made from plastic. Company X often has problems with the quality of the products produced, especially valve products as products that are produced every day. The corrective step used to assist Company X in improving the quality of valve products is the application of the PDCA method. PDCA method consists of the plan, do, check, and act stages. The proposed improvement design was carried out based on the results of data processing and obtained as many as 9 proposed improvements. In the do stage, implementation of the proposed improvements that have been designed is carried out, five proposed improvements can be implemented and the other four in the form of recommendations. Next is the check stage, which is the process of collecting data again on the results of the implementation of the proposed improvement. Based on the results of the check stage, a standardization process was carried out at the act stage to improve the performance of the proposed improvement and the quality of the valve product. Standardization is done by changing or improving the proposed improvements that have been implemented. Research has succeeded in reducing the number of defective valve products with the proportion of defects that were previously 1.16% to 0.57%.

Hemolysis following a mitral valve prosthesis surgery: etiology, diagnosis and treatment

Domas Grigoravičius1 1 Vilnius University, Faculty of Medicine, Vilnius, Lithuania Abstract Introduction: anemia caused by heart valve prostheses is not a common but significant type of hemolytic anemia, despite the lack of information on this complication in the literature. There is no clear pathogenesis of the etiology of this condition. The primary mechanism of hemolytic anemia after valve replacement surgery is regurgitation due to valve leakage. Aim: this work aims to review the literature on the etiology, diagnosis, and treatment of valve-induced hemolytic anemia. Literature search strategy: the literature search was conducted using the PubMed and Google Scholar databases. The following keywords and their combinations were used: “hemolysis,” “valve replacement,” “treatment,” “diagnosis,” “surgery”. Conclusions: the diagnosis of hemolytic anemia caused by valve prostheses is problematic because it can be an early and late postoperative complication, and the condition must be differentiated from other possible causes of hemolysis even after the detection of hemolytic markers. Medication is sufficient to treat mild hemolytic anemia caused by valve prostheses, but surgical treatment and replacement of a defective valve are the most common. Keywords: valve replacement; hemolytic anemia; postoperative complication.

Foxo1 deletion promotes the growth of new lymphatic valves.

Patients with congenital lymphedema suffer from tissue swelling in part due to mutations in genes regulating lymphatic valve development. Lymphatic valve leaflets grow and are maintained throughout life in response to oscillatory shear stress (OSS), which regulates gene transcription in lymphatic endothelial cells (LECs). Here, we identified the first transcription factor, Foxo1, that repressed lymphatic valve formation by inhibiting the expression of valve-forming genes. We showed that both embryonic and postnatal ablation of Foxo1 in LECs induced additional valve formation in postnatal and adult mice in multiple tissues. Our quantitative analyses revealed that after deletion, the total number of valves in the mesentery was significantly (P < 0.01) increased in the Foxo1LEC-KO mice compared with Foxo1fl/fl controls. In addition, our quantitative real-time PCR (RT-PCR) data from cultured LECs showed that many valve-forming genes were significantly (P < 0.01) upregulated upon knockdown of FOXO1. To confirm our findings in vivo, rescue experiments showed that Foxc2+/- mice, a model of lymphedema-distichiasis, had 50% fewer lymphatic valves and that the remaining valves exhibited backleak. Both valve number and function were completely restored to control levels upon Foxo1 deletion. These findings established FOXO1 as a clinically relevant target to stimulate de novo lymphatic valve formation and rescue defective valves in congenital lymphedema.

Transcription factor FOXP2 is a flow‐induced regulator of collecting lymphatic vessels

The lymphatic system is composed of a hierarchical network of fluid absorbing lymphatic capillaries and transporting collecting vessels. Despite distinct functions and morphologies, molecular mechanisms that regulate the identity of the different vessel types are poorly understood. Through transcriptional analysis of murine dermal lymphatic endothelial cells (LECs), we identified Foxp2, a member of the FOXP family of transcription factors implicated in speech development, as a collecting vessel signature gene. FOXP2 expression was induced after initiation of lymph flow in vivo and upon shear stress on primary LECs in vitro. Loss of FOXC2, the major flow‐responsive transcriptional regulator of lymphatic valve formation, abolished FOXP2 induction in vitro and in vivo. Genetic deletion of Foxp2 in mice using the endothelial‐specific Tie2‐Cre or the tamoxifen‐inducible LEC‐specific Prox1‐CreERT2 line resulted in enlarged collecting vessels and defective valves characterized by loss of NFATc1 activity. Our results identify FOXP2 as a new flow‐induced transcriptional regulator of collecting lymphatic vessel morphogenesis and highlight the existence of unique transcription factor codes in the establishment of vessel‐type‐specific endothelial cell identities.

A Prospective Study on Clinical Presentation and Surgical Management of Varicose Veins at a Tertiary Care Hospital in Bangalore, India

Introduction: Varicose veins are abnormally dilated veins of lower limbs with defective valves. Incidence involves one out of five in the world and the problem is ever growing due to increasing population, increased life span and change in life style. Hence, there is a need to delineate the epidemiology of the varicose veins in the local population which visited the hospital. Aim: To study the various clinical presentations, management and complications of varicose veins. Materials and Methods: It was a prospective observational study; conducted by the Department of General surgery at Sri Siddhartha Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India from September 2018-February 2020. All 75 patients enrolled were evaluated by detailed history, clinical examination and investigations- venous doppler study of the lower limbs, to locate the site of incompetence. All the cases that underwent surgical procedure were followed postoperatively for any complications every one month for development of surgical site infections, after three months for healing of ulcer and at six months for any signs of recurrence. The collected data was entered in Microsoft Excel spread sheet and analysed using descriptive statistics. Results: The study included 75 cases with primary varicose veins. The age of these patients ranged from 21-69 years. Male to female ratio was 1.5:1. Most of them were farmers (48%) by occupation requiring prolonged hours of standing. All cases presented with dilated veins. The common associated symptoms were pain (50.7%) followed by itching (28%) with slight increased incidence in the left lower limb (50.7%). Majority of the patients have involvement of long sephenous system (81.3%). Majority of them (48%) had combined valvular incompetence. Sapheno-femoral flush ligation with stripping appeared to be the best method of surgical management for incompetence in the long saphenous vein territory. Ten (13.3%) cases had postoperative complications. Conclusion: Varicose veins are a common disease, middle age group, males and occupation with prolonged hours of standing are affected the most. Surgical procedures have beneficial effects in minimising morbidity due to varicose vein.

Identification by mass spectrometry and immunoblotting of xenogeneic antigens in the N- and O-glycomes of porcine, bovine and equine heart tissues

Animal bioprosthetic heart valves (BHV) are used to replace defective valves in patients with valvular heart disease. Especially young BHV recipients may experience a structural valve deterioration caused by an immune reaction in which α-Gal and Neu5Gc are potential target antigens. The expression of these and other carbohydrate antigens in animal tissues used for production of BHV was explored. Protein lysates of porcine aortic and pulmonary valves, and porcine, bovine and equine pericardia were analyzed by Western blotting using anti-carbohydrate antibodies and lectins. N-glycans were released by PNGase F digestion and O-glycans by β-elimination. Released oligosaccharides were analyzed by liquid chromatography – tandem mass spectrometry. In total, 102 N-glycans and 40 O-glycans were identified in animal heart tissue lysates. The N- and O-glycan patterns were different between species. α-Gal and Neu5Gc were identified on both N- and O-linked glycans, N,N´-diacetyllactosamine (LacdiNAc) on N-glycans only and sulfated O-glycans. The relative amounts of α-Gal-containing N-glycans were higher in bovine compared to equine and porcine pericardia. In contrast to the restricted number of proteins carrying α-Gal and LacdiNAc, the distribution of proteins carrying Neu5Gc-determinants varied between species and between different tissues of the same species. Porcine pericardium carried the highest level of Neu5Gc-sialylated O-glycans, and bovine pericardium the highest level of Neu5Gc-sialylated N-glycans. The identified N- and O-linked glycans, some of which may be immunogenic and remain in BHVs manufactured for clinical use, could direct future genetic engineering to prevent glycan expression rendering the donor tissues less immunogenic in humans.

Performance Analysis of Stiction Detection Methods

Industrial studies stated that, nearly 30% of badly performing process control loops are produced by nonlinearities in the pneumatic control valves, one among the main cause is stiction. The influence of this stiction nonlinearity is commonly detected as the process variable oscillations. As industrial plants contain several loops that are interacting, these oscillations will be spread to the whole system. Overhauling the defective valves will be the one among the top solution to this problem, which is probable only during the period of shut down process. But, this solution of process shut down to separate the defective valve is not cost-effective solution and hence it is taken into account as the prime one. So, there is a necessity for a technique to identify the effect of the control valve stiction. Detection algorithms available in literature are numerous and these techniques create either a quantitative or a qualitative statement about the occurrence of stiction in the control valve. While using available data, a detection method is considered to be effective only when its concluding result is relatively reliable. The main drawback while detecting stiction is that the stem position (MV) of the valve is not available in most of the situations. Quantifying the actual position of the control valve stem is always not probable. Commonly, process output and controller output are taken as the available data from most of the processes. The methods which use these data sets (PV and OP) are more appreciable by the control engineers. In this work, modified bispectral analysis technique is used as control valve stiction detection method and to prove its efficiency four different existing detection techniques available in literature are considered in this study and the performance of each method is reported. Here, eleven different data sets, seven from different laboratory processes and four from process industries are used to make the comparative analysis of performance.

Observations of changes in acoustic emission parameters for varying corrosion defect in reciprocating compressor valves

Abstract Acoustic Emission (AE) technology is probably one of the most recent entries in the field of machinery condition monitoring. This paper investigates the application of AE parameters for valve faults detection in reciprocating compressor. The defective valves were designed by emulating the actual valve corrosion with varying sizes such that defects could be applied onto the reciprocating compressor. A set of experiments was performed to acquire the AE signal. The primary source of AE signal was verified using waveform analysis. The AE parameters versus different operational and valve condition were illustrated individually. In addition, the significance of the change and sensitivity of AE parameters versus different experimental conditions was verified using MANOVA and coefficient of variance analysis. It is concluded that the AE signal parameters can be used to detect the valve faults in the reciprocating compressor with the consideration of the variation in the AE parameters sensitivity.

Cervical compressive myelopathy caused by malfunction of a programmable cerebrospinal fluid shunt valve

Abstract The primary treatment for hydrocephalus is ventricular shunt placement, and a programmable valve is widely used for ventriculoperitoneal (VP) shunt surgery to reduce over/under drainage of cerebrospinal fluid (CSF). Here, we report a rare case of a patient who developed successive VP shunt malfunction causing spastic muscle weakness in extremities associated cervical epidural venous distension and compressive myelopathy due to over-drainage of CSF through a defective VP shunt valve a decade after the initial shunt was placed. One should be aware and cognizant of this complication and carefully follow the symptoms and potentially utilize brain MRI with and without contrast to look at over drainage stigmata to avoid the development of neurological complications.

High Resolution M-mode Evaluation of Jugular Vein Valves in Patients with Neurological and Neurosensory Disorders.

High prevalence of valve absence was found in the internal jugular vein (IJV) of healthy volunteers by means of M-mode high-resolution Echo Colour Doppler (ECD). However, the prevalence of valve in neurovascular disorders linked to Chronic Cerebrospinal Venous Insufficiency (CCSVI) is still unknown. A cohort of 83 Healthy Controls (HC), 71 Multiple Sclerosis (MS), 99 Inner Ear Disorders (IED) underwent ECD investigation of the IJV valve, including M-mode evaluation and related hemodynamics. The primary outcome measure was characterization of valve presence, morphology and motility, whereas the secondary outcome was the rate of flow alteration. Bilateral valve presence was found in 38% of HC, 58% of MS and 25% of IED, whereas, bilateral valve absence was recorded in 16% of HC, 10% of MS and 31% of IED (p<0.003). Bicuspid morphology was more prevalent in HC 56%, while monocusp was more prevalent in patients: 75% MS and 57% IED (p<0.0001). The main finding was the presence of mobile valve leaflets in 98% of HC, contrarily fixed valve leaflets were recorded in 82% of MS and in 41% of IED, p< 0.0001. Finally, by stratifying the entire cohort according to the presence of mobile and not mobile valve leaflets, normal monodirectional and phasic flow were commonly found in the mobile leaflets subgroup, p<0.0001. In patients with miscellaneous neurological disorders, a significant higher rate of defective valves was found with respect to HC. The latter condition is strongly associated to brain outflow abnormalities described in CCSVI condition.

Hemodynamic Forces Sculpt Developing Heart Valves through a KLF2-WNT9B Paracrine Signaling Axis

Hemodynamic forces play an essential epigenetic role in heart valve development, but how they do so is not known. Here, we show that the shear-responsive transcription factor KLF2 is required in endocardial cells to regulate the mesenchymal cell responses that remodel cardiac cushions to mature valves. Endocardial Klf2 deficiency results in defective valve formation associated with loss of Wnt9b expression and reduced canonical WNT signaling in neighboring mesenchymal cells, a phenotype reproduced by endocardial-specific loss of Wnt9b. Studies in zebrafish embryos reveal that wnt9b expression is similarly restricted to the endocardial cells overlying the developing heart valves and is dependent upon both hemodynamic shear forces and klf2a expression. These studies identify KLF2-WNT9B signaling as a conserved molecular mechanism by which fluid forces sensed by endothelial cells direct the complex cellular process of heart valve development and suggest that congenital valve defects may arise due to subtle defects in this mechanotransduction pathway.

Applicability of handmade expanded polytetrafluoroethylene trileaflet-valved conduits for pulmonary valve reconstruction: An ex vivo and in vivo study

ObjectiveThe handmade expanded polytetrafluoroethylene (ePTFE) trileaflet-valved conduit could potentially be used as a substitute pulmonary valve replacement material, especially in children. The current study investigated (1) the function of the ePTFE trileaflet-valved conduits in an ex vivo experimental system and (2) the short-term performance of the conduit in a porcine model to verify its clinical applicability. MethodsThe competency of the ePTFE trileaflet-valved conduits was estimated through ex vivo (using a pulmonary mock circulation loop) and in vivo (in a porcine model with a damaged pulmonary valve) experiments. Explants were examined by gross morphology and histopathologic examination. ResultsIn the ex vivo experiment, the ePTFE trileaflet-valved conduits were determined to effectively increase mean pulmonary pressure from 10.2 to 14.4 mm Hg compared with defective silicon-valved conduits. In addition, the regurgitation fraction value of ePTFE trileaflet-valved conduits was 15.9% to 18.1%, which was significantly better than the defective valve conduits (regurgitation fraction = 73.5%-85.7%). In the in vivo experiment, the valved conduits were confirmed to be with good valve position maintenance, and the valve and leaflets showed no signs of thickening or peeling after a short-term implantation period. There were also no significant signs of inflammation reaction on histopathologic examination. ConclusionsThe ePTFE trileaflet-valved conduits for pulmonary valve reconstruction showed acceptable performance and outcomes in the ex vivo and in vivo experiments. The ePTFE trileaflet-valved conduit may be clinically useful, although additional studies in animals should be conducted to determine its long-term outcomes.

Retrograde Lymph Flow Leads to Chylothorax in Transgenic Mice with Lymphatic Malformations

Chylous pleural effusion (chylothorax) frequently accompanies lymphatic vessel malformations and other conditions with lymphatic defects. Although retrograde flow of chyle from the thoracic duct is considered a potential mechanism underlying chylothorax in patients and mouse models, the path chyle takes to reach the thoracic cavity is unclear. Herein, we use a novel transgenic mouse model, where doxycycline-induced overexpression of vascular endothelial growth factor (VEGF)-C was driven by the adipocyte-specific promoter adiponectin (ADN), to determine how chylothorax forms. Surprisingly, 100% of adult ADN-VEGF-C mice developed chylothorax within 7 days. Rapid, consistent appearance of chylothorax enabled us to examine the step-by-step development in otherwise normal adult mice. Dynamic imaging with a fluorescent tracer revealed that lymph in the thoracic duct of these mice could enter the thoracic cavity by retrograde flow into enlarged paravertebral lymphatics and subpleural lymphatic plexuses that had incompetent lymphatic valves. Pleural mesothelium overlying the lymphatic plexuses underwent exfoliation that increased during doxycycline exposure. Together, thefindings indicate that chylothorax in ADN-VEGF-C mice results from retrograde flow of chyle from the thoracic duct into lymphatic tributaries with defective valves. Chyle extravasates from these plexuses and enters the thoracic cavity through exfoliated regions of the pleural mesothelium.

ANALISIS PENGENDALIAN KUALITAS PRODUK KANTONG SEMEN PADA LINE IV PABRIK KANTONG PT SEMEN PADANG

PT Semen Padang is the oldest cement factory in Indonesia was established on March 18, 1910. Semen Padang is located in the Village District of Lubuk Kilangan Indarung Madya city of Padang, approximately 15 km from the center of Padang West Sumatra at an altitude of 350 above sea level. PT Semen Padang not only produce high quality cement, but also manufacture cement bags which will facilitate the distribution of cement. Bags of cement were produced under the Ministry of Transportation Distribution and PT Semen Padang or Bureau bag factory located at Km 2 By Pass street, Padang. Bureau bag factory produces 40 Kg bag with size and the size of 50 kg. Based on the results of the overall discussion on the control of product quality cement bags known that quality control is implemented is still not optimal. Paretto diagram of the processing, there are six causes of disability among other cement bags 1. Defects in the logo, 2. Glue the tube body portion is not flat, 3. Tube not cut / no separate, 4. Installation of the valve / valve is not appropriate, 5. Glue at the top and bottom of the bag uneven, and 6. Fold the top and bottom are not perfect. The most dominant defect occurs during the production process on line IV, namely, fold the top and bottom of the bag is not perfect for 26 280 of the 77 295 total defective products, defective bags or 34% of the total number of defective products and improper valve installation for 23 575 of the 77 295 total products disability, which has a defect rate of 30.5% of the existing number of defective products. Selanjutya based on analysis of a causal diagram is known that factors that cause many machining equipment occurred a defective product, so it needs to be evaluated again on machinery and equipment so as to reduce or eliminate defects that may occur. Then on analysis using p control map for the entire product defects that occur in the production process shows that not all the data are within the control limits. Keywords: Cause and Effect Diagram, Cement Bags, Control Charts P, Defective Products, Pareto Diagram, Quality Control.

On-demand generation and removal of alginate biocompatible microvalves for flow control in microfluidics

This paper describes, for the first time, the use of alginate hydrogels as miniaturised microvalves within microfluidic devices. These biocompatible and biodegradable microvalves are generated in situ and on demand, allowing for microfluidic flow control. The microfluidic devices were fabricated using an origami inspired technique of folding several layers of cyclic olefin polymer followed by thermocompression bonding. The hydrogels can be dehydrated at mild temperatures, 37°C, to slightly open the microvalve and chemically erased using an ethylenediaminetetraacetic acid disodium salt (EDTA) solution, to completely open the channel, ensuring the reusability of the whole device and removal of damaged or defective valves for subsequent regeneration.

Approaches for Monitoring the Energy Consumption with Machine Learning Methods

In times of rising energy costs and increasing customer awareness of sustainable production methods, many manufacturers take measures to reduce their energy consumption. However, after the realization of such activities the energy demand often tends to increase again due to e.g. leaks, clogged filters, defect valves or suboptimal parameter settings. In order to prevent this, it is necessary to quickly identify such increases by continuously monitoring the energy consumption and counteracting accordingly. Currently, the monitoring is either performed manually or by setting static threshold values. The manual control can be time consuming for large amounts of sensor data. By setting static threshold values only a fraction of the inefficiencies are disclosed. Another option is to use anomaly detection methods from the area of machine learning, which compare the actual sensor values with the expected ones. In this paper an overview about existing anomaly detection methods, which can be applied for this purpose, is presented.