Tube Loop Research Articles

Solar energy utilization for underfloor heating system in residential buildings

In this paper, the thermal performance of a solar energy system for heating a residential building is experimentally investigated. In this system, the solar thermal energy is supplied via a flat plate solar collector that provides the heated water into a small-scale chamber, that represents the residential building. The experimental setup is installed in Jouf University campus (Latitude: 29° 47′ 1.9” N, Longitude: 40° 2′ 42.2” E) located at Al-Jouf Province, Saudi Arabia. In this experiment, the hot water supplied from solar collector is mixed with water in the storage tank, then extracted from bottom of the tank to be circulated in a copper tube loop located underneath the floor tiles of the chamber and hence increases the chamber’s air temperature. Two circulation pumps are installed in the system, one to circulate the water between solar collector and storage tank and the other to circulate the water between storage tank and chamber. Measurements of several parameters were conducted to evaluate the overall thermal efficiency of the system. The experimental results showed an average efficiency of 51 %, when operating the system for eight-hours duration in the winter season. Additionally, an economic assessment was carried out to confirm the system’s feasibility. This assessment demonstrated that the constructed system is economically feasible, with an estimated benefit-cost ratio of 1.42.

Experimental study of a low-cost reversible thermal diode for advanced heat manipulation

A low-cost reversible thermal diode was fabricated by a copper tube loop incorporating a valve in the top channel for advanced thermal management. The inner surface of one vertical tube was treated to superhydrophobic, while that of the other vertical tube was modified to superhydrophilic and further loaded with a superhydrophilic copper mesh for water wicking. Furthermore, the valve in the top channel can behave as a switch to control the hot vapor flow between the two vertical tubes. Then, different heat powers from 5 W to 15 W were applied to investigate the rectification effect of the thermal diode under low (30 %), medium (50 %), and high (70 %) filling ratios (FR) of the working fluid. The results showed that its rectification ratio could exceed 2.8 with the help of the control valve at FR = 30 %. Furthermore, the rectification effect could be reversed by the valve without flipping the thermal diode. In reversible working mode, the reversed heat transport could reach twice of the forward heat transport at FR = 50 %. Therefore, owning to the reversible heat transfer capacity, this study can guide the advanced thermal diode design for unstable waste heat recovery, solar energy harvesting, building energy management, etc.

Case study: reducing heating energy consumption in a high tunnel greenhouse with renewable energy and microclimate control by bench-top root-zone heating, bench covers, and under-bench insulation

Appalachian State University's Nexus project designed an efficient greenhouse heating system that integrated renewable energy and root zone heating technology to reduce the greenhouse heating energy burden on local farmers and installed it at local cooperative farms. This study analyzed 5 years of data from 2018 to 2022 to investigate the energy savings and microclimate control effectiveness of the Nexus heating system installed at Springhouse Farm in North Carolina, USA. By varying bench cover materials, bottom insulation, and the number of loops of root zone tubing, the different soil temperatures required for plant types and growth stages were achieved with a single temperature controller. A root zone heating fluid of 32.2 ℃ satisfactorily maintained the germination soil between 20 and 25 ℃ in March 2019 with an average outside temperature of 4.8 ℃ and an average low temperature of − 0.4 ℃. Growing soil maintained an average temperature of 15 ℃ with bottom insulation and an average of 11–12 ℃ without bottom insulation. Compared to the conventional heating system (a forced-air propane unit heater alone), weather-adjusted propane consumption (propane usage divided by heating degree days) was reduced by 65% with the Nexus system alone and 45% with the Nexus system and unit heater together. It shows that the Nexus system has significantly reduced greenhouse heating energy consumption and maintained productive conditions. The renewable energy fraction ranged only 9–13% of the total thermal energy used due to the high inlet temperature entering the solar thermal collector. This can be improved by separating the heat storage and backup heat source.

Focal Adhesion's Role in Cardiomyocytes Function: From Cardiomyogenesis to Mechanotransduction.

Mechanotransduction refers to the ability of cells to sense mechanical stimuli and convert them into biochemical signals. In this context, the key players are focal adhesions (FAs): multiprotein complexes that link intracellular actin bundles and the extracellular matrix (ECM). FAs are involved in cellular adhesion, growth, differentiation, gene expression, migration, communication, force transmission, and contractility. Focal adhesion signaling molecules, including Focal Adhesion Kinase (FAK), integrins, vinculin, and paxillin, also play pivotal roles in cardiomyogenesis, impacting cell proliferation and heart tube looping. In fact, cardiomyocytes sense ECM stiffness through integrins, modulating signaling pathways like PI3K/AKT and Wnt/β-catenin. Moreover, FAK/Src complex activation mediates cardiac hypertrophic growth and survival signaling in response to mechanical loads. This review provides an overview of the molecular and mechanical mechanisms underlying the crosstalk between FAs and cardiac differentiation, as well as the role of FA-mediated mechanotransduction in guiding cardiac muscle responses to mechanical stimuli.

Reports of Gastric Banding and Bowel Obstruction: A Narrative Review of the Literature.

The utilization rates of laparoscopic gastric banding (LAGB) declined worldwide from 42.3% in 2008 to 1.8% in 2018. Rates of complications requiring removal may reach 40-50% in the medium to long term. Bowel obstruction is a rare but severe complication that occurs after LAGB. A comprehensive literature search in PubMed was carried out to identify all available case reports of intestinal obstruction after gastric banding. The search terms were as follows: "intestinal obstruction", "small bowel obstruction", "gastric band", "gastric banding", "gastric band complications", and "laparoscopic gastric band obstruction". The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) flowchart was used. Forty-three case reports were included in our review. Laparotomy was necessary in 18/43 (41%) of patients. Vomit was not always reported, while abdominal pain was constantly present. A CT scan was the preferred diagnostic tool. The main causes of occlusion were found to be the erosion of the gastrointestinal tract or internal hernia due to a loose tube loop. Forty-six percent of cases occurred within 5 years from insertion. Even if rare, small bowel obstruction after LAGB requires surgical intervention often with an open approach. The absence of vomit masks symptoms, but an obstruction must be always suspected in the case of severe colicky abdominal pain. A CT scan is recommended for making diagnoses.

Real-Time Detection of Circulating Thrombi in an Extracorporeal Circuit Using Doppler Ultrasound: In-Vitro Proof of Concept Study.

Thromboembolic stroke continues to be by far the most common severe adverse event in patients supported with mechanical circulatory assist devices. Feasibility of using Doppler ultrasound to detect circulating thrombi in an extracorporeal circuit was investigated. A mock extracorporeal circulatory loop of uncoated cardiopulmonary bypass tubing and a roller pump was setup. A Doppler bubble counter was used to monitor the mean ultrasound backscatter signal (MUBS). The study involved two sets of experiments. In Scenario 1, the circuit was sequentially primed with human blood components, and the MUBS was measured. In Scenario 2, the circuit was primed with heparinized fresh porcine blood, and the MUBS was measured. Fresh blood clots (diameter <1,000 microns, 1,000-5,000 microns, >5,000 microns) were injected into the circuit followed by protamine administration. In Scenario 1 (n = 3), human platelets produced a baseline MUBS of 1.5 to 3.5 volts/s. Addition of packed human red blood cells increased the baseline backscatter to 17 to 21 volts/s. Addition of fresh frozen plasma did not change the baseline backscatter. In Scenario 2 (n = 5), the blood-primed circuit produced a steady baseline MUBS. Injection of the clots resulted in abrupt and transient increase (range: 3-30 volts/s) of the baseline MUBS. Protamine administration resulted in a sustained increase of MUBS followed by circuit thrombosis. Doppler ultrasound may be used for real-time detection of circulating solid microemboli in the extracorporeal circuit. This technology could potentially be used to design safety systems that can reduce the risk of thromboembolic stroke associated with mechanical circulatory support therapy.

In Vitro Thrombogenicity Testing of Biomaterials in a Dynamic Flow Loop: Effects of Length and Quantity of Test Samples.

The results of in vitro dynamic thrombogenicity testing of biomaterials and medical devices can be significantly impacted by test conditions. To develop and standardize a robust dynamic in vitro thrombogenicity tool, the key test parameters need to be appropriately evaluated and optimized. We used a flow loop test system previously developed in our laboratory to investigate the effects of sample length and the number of samples per test loop on the thrombogenicity results. Porcine blood heparinized to a donor-specific target concentration was recirculated at room temperature through polyvinyl chloride (PVC) tubing loops containing test materials for 1 h at 200 mL/min. Four test materials (polytetrafluoroethylene (PTFE), latex, PVC, and silicone) with various thrombotic potentials in two sample lengths (12 and 18 cm) were examined. For the 12-cm long materials, two different test configurations (one and two samples per loop) were compared. Thrombogenicity was assessed through percent thrombus surface coverage, thrombus weight, and platelet count reduction in the blood. The test system was able to effectively differentiate the thrombogenicity profile of the materials (latex > silicone > PVC ≥ PTFE) at all test configurations. Increasing test sample length by 50% did not significantly impact the test results as both 12 and 18 cm sample lengths were shown to equally differentiate thrombotic potentials between the materials. The addition of a second test sample to each loop did not increase the test sensitivity and may produce confounding results, and thus a single test sample per loop is recommended.

Embryonic development of Indonesian native fish yellow rasbora (Rasbora lateristriata)

ObjectivesYellow rasbora (Rasbora lateristriata) exhibits potential as a novel animal model for research purposes. Nevertheless, the process of embryonic development of this fish species remains inadequately comprehended. This study aimed to characterize the embryonic development stages of yellow rasbora. MethodsThe embryonic development was documented using time-lapse technique to observe the following parameters: the embryonic cleavage, the blastomere, the epiboly area, and the somites. Heart development and morphological changes were also observed, including the number of heartbeats at 24, 30, 48 h post-fertilization. The cartilage structure in the cranium of larvae aged 1 to 3 days post-fertilization were observed as well. Alizarin red and Alcian blue staining were used to stain bone and cartilage structures. ResultsThe results of this study describe the important stages of embryogenesis in yellow rasbora, including the zygote, cleavage, blastula, gastrula, segmentation, pharyngula, and hatching stages. The first contraction of the heart muscle was observed at 20 h post-fertilization, with cardiac tube looping occurred at 24–30 h post-fertilization. The cranium cartilage was formed 2 days post-fertilization and completed at 3 days post-fertilization. ConclusionIn conclusion, this study provided a comprehensive overview of the developmental stages of yellow rasbora embryos.

P37: Development of a Large Diameter In Vitro Flow Loop Thrombogenicity Test System

Purpose: To accommodate a wide range of medical device sizes for in vitro thrombogenicity testing, a larger flow loop system using 9.5 mm inner diameter (ID) tubing was developed and evaluated based on the 6.4 mm ID system that we previously used. Methods: Four cardiopulmonary bypass roller pumps were used concurrently to drive four different flow loops constructed with 9.5 mm ID polyvinyl chloride (PVC) tubing. To ensure that the four pumps produced a consistent blood flow rate (around 530 mL/min), a simplified dynamic roller-occlusion method was developed and applied. ACDA-anticoagulated bovine blood from live donors was obtained commercially, shipped overnight, and used within 24-36 hours of the blood draw. Immediately before starting each flow loop test, the blood was recalcified and heparinized to a donor-specific concentration (0.5 – 0.8 U/mL). The donor-specific heparin level was selected based on an established static pre-test and verified by an initial flow loop test with the following acceptance criteria: thrombus surface coverages of ≤10% on the negative control (PTFE) and ≥50% on the positive control (latex) materials, and platelet (PLT) reduction of ≤30% for the negative control and ≥90% for the positive control. For the dynamic testing, the heparinized blood was recirculated at 20 rpm for 1 hour at room temperature through each PVC tubing loop containing a test material. Six materials (3.2 mm OD, 12 cm long) with different thrombogenic potentials were assessed: negative control polytetrafluoroethylene (PTFE), positive control latex, BUNA rubber, silicone, abraded PTFE, and 3D printed nylon. Thrombogenicity potentials of the test materials were evaluated after the recirculation by measuring the thrombus surface coverage on test materials and platelet count reduction in the blood samples. Results: The in vitro flow loop test system effectively differentiated the known thrombogenic materials (latex, BUNA) from the historically thromboresistant PTFE (p<0.05 for PLT count reduction and thrombus surface coverage, Figure 1). Additionally, the 3D printed nylon and silicone test samples were shown to have an intermediate thrombogenicity level with significantly less thrombus surface coverage and PLT count reduction than latex and BUNA, but significantly more thrombus surface coverage than the PTFE (p<0.05). While the average PLT count reductions for the 3D printed nylon and silicone were also greater than that of PTFE, the differences were not statistically significant. Conclusion: The preliminary data suggest that the 9.5 mm ID test system is capable of differentiating materials of varying thrombogenicity potentials, and the different pumps can produce consistent results when appropriate occlusion settings are used. This system will be further investigated in an ASTM interlaboratory study to develop standardized best practices for performing in vitro dynamic thrombogenicity testing of medical devices and materials.Figure 1. A) Platelet count reduction, and B) Thrombus surface coverage on test material after 1 hour blood recirculation at room temperature. Data are shown as a mean ± standard error. n=4 for all materials, except BUNA and silicone (n=3). *p<0.05.

Effect of Temperature on Thrombogenicity Testing of Biomaterials in an In Vitro Dynamic Flow Loop System.

To develop and standardize a reliable in vitro dynamic thrombogenicity test protocol, the key test parameters that could impact thrombus formation need to be investigated and understood. In this study, we evaluated the effect of temperature on the thrombogenic responses (thrombus surface coverage, thrombus weight, and platelet count reduction) of various materials using an in vitro blood flow loop test system. Whole blood from live sheep and cow donors was used to assess four materials with varying thrombogenic potentials: negative-control polytetrafluoroethylene (PTFE), positive-control latex, silicone, and high-density polyethylene (HDPE). Blood, heparinized to a donor-specific concentration, was recirculated through a polyvinyl chloride tubing loop containing the test material at room temperature (22-24°C) for 1 hour, or at 37°C for 1 or 2 hours. The flow loop system could effectively differentiate a thrombogenic material (latex) from the other materials for both test temperatures and blood species ( p < 0.05). However, compared with 37°C, testing at room temperature appeared to have slightly better sensitivity in differentiating silicone (intermediate thrombogenic potential) from the relatively thromboresistant materials (PTFE and HDPE, p < 0.05). These data suggest that testing at room temperature may be a viable option for dynamic thrombogenicity assessment of biomaterials and medical devices.

An improved visual closed tube Loop mediated isothermal amplification (LAMP) assay for rapid identification of orf virus in sheep and goats.

The orf virus (ORFV) is an epitheliotropic virus causing a highly contagious skin disease mainly in sheep and goats. Several diagnostics including molecular tools like Loop mediated isothermal amplification (LAMP) assay are available to detect ORFV in affected species. However, the carry-over contamination associated with LAMP as open tube format prevents the assay applicability as point of care test in field diagnostic settings. In this study, the B2L gene based LAMP assay was optimized in a closed tube format using hydroxynaphthol blue (HNB) and calcein as pre-addition dyes and it has shown a clear positive and negative signal at 60 °C using 4 and 5 mM concentrations of MgSO4 respectively for these dyes. Optimitimzed assay that could reveal the result within one hour is highly specific and senstive with a limit of detection at 12.5 femtogram of viral genomic DNA or ~85 virus genome equivalent. This improved method prevented the cross-contamination of future LAMP reactions in the laboratory without compromising diagnostic sensitivity (100%) and specificity (100%) when compared to open tube system. This closed tube LAMP method has potential to act as a simple visual detection assay for the rapid and specific diagnosis of ORFV in sheep and goats.

Genetics of congenitally corrected transposition of the great arteries: Whole-exome sequencing shows a mutation load effect in 156 genes involved in cardiac patterning

Congenital Heart Disease (CHD) is a major public health issue. About 20% of CHD correspond to a misalignment between cardiac segments. We focused on a rare CHD, the congenitally corrected transposition of the great arteries (CCTGA). The aim of this study was to understand the mechanisms and genes that control the alignment of cardiac chambers, and thus lead to the CCTGA. We analyzed a cohort of 44 CCTGA cases (42 sporadic cases and 2 familial cases) of non-syndromic CCTGA by next generation sequencing analysis (whole-genome and whole-exome sequencing). Under the hypothesis of Mendelian model with de novo genomic alterations, no major gene involved in the disease could be identified. Under the hypothesis of a complex model of inheritance with incomplete penetrance, a total gene set of 156 genes matched each of our selection criteria. The highly heterogeneous combinations of susceptibility rare variants, mostly inherited from the healthy mother and father respectively, functionally converge to give rise to the CCTGA phenotype. To prove that a given allele combination is associated with the CCTGA phenotype, we showed a significant enrichment of rare variants in cases, any given deleterious variant combination within the CCTGA gene set being specific to the affected individual. Taken together, the cases could be explained by a mutation load of segregated alleles at loci mostly involved in heart tube looping, outflow tract morphogenesis and establishment of left-right asymmetry. Our data contradict a monogenic mode of inheritance, favouring a multigenic origin of CCTGA, where both parents harbour genetic predisposition variants for the disease (susceptibility alleles) and both transmit this load of variants to the affected offspring, explaining the low recurrence risk.

A COMPARISON BETWEEN TWO METHODS OF FALLOPIAN TUBAL LIGATION FOR STERILIZATION OF WOMEN IN A LOW RESOURCE SETTING

Objective: To compare two methods of tubal sterilization; modied Pomeroy and a modication added to modied Pomeroy's method, in a low resource setting. In this prospective study conducted fromMethods: 2019 to 2021 in one thousand women, we compared Pomeroy's method with an other method in which a slight modication in the original modied Pomeroy's technique was introduced, in a very low resource rural community hospital with only basic operation theater facility. In modied Pomeroy's method, a loop of fallopian tube is resected and transxed with 2-0 chromic catgut surgical suture material. In our study we added another modication to the modied Pomeroy's method, wherein the proximal end of the fallopian tube was additionally ligated with a 2-0 silk suture. The patients were followed up from 6months-2 years. A failure rate of 0.4% was observed in women who underwent Modied Pomeroy's method in contrast to noResults: failure in women in whom the proximal end of the tube was additionally ligated. Additional modication to theConclusion: original modied Pomeroy's method of sterilization can be potentially promising in reduction of sterilization failure rate in parts of world where salpingectomy is less readily accepted.

Pathogenesis of peritoneal drain complications; a case report of evolving adnexal evisceration following difficult retrieval of a retained peritoneal drain

Background: Intra-peritoneal drainage dates back to the time of Hippocrates when long bone tissue, metal, and glass tubes were employed. The benefit of routine intra-peritoneal drainage however remains debatable in contemporary times. Retained drains may be outward manifestations of more sinister or latent complications and how an entrapped surgical drain is removed, may determine the occurrence of further complications. Case Presentation: We report here the case of a 32-year-old primipara who had a retained improvised peritoneal drain, which was inserted during the cesarean section for continued oozing of serosanguineous fluid. Omental tissue found at laparoscopy, to have plugged a fenestration in the drain, was promptly relieved. A loop of the Fallopian tube was however later observed trapped in another fenestration and herniating into the stab incision of the drain tube towards the exterior, this was freed with an atraumatic laparoscopic grasper and drain tube retrieval completed under laparoscopic visualization. Conclusion: Insertion of the peritoneal drain during cesarean section should be carefully considered, when necessary; it should be done with the most appropriate drainage systems. Retrieval of the peritoneal drain is a risk factor for visceral herniation. Entrapped drains should be retrieved, under direct visualization, to prevent iatrogenic injuries.

Heat-pipe-based tunable multimode horizontal thermal rectifier

A heat-pipe-based multimode thermal rectifier, easily scalable for advanced thermal energy management in industrial applications (e.g., waste heat recovery, solar energy application and building energy management), is proposed for horizontal heat transport. The thermal rectifier is composed of a copper tube loop having a superhydrophilic section and a superhydrophobic section. The thermal rectification effect is achieved by the differences of the superhydrophilic and superhydrophobic sections in surface evaporation/condensation and wicking characteristics, when they are exposed to heating or cooling. Meanwhile, a valve is incorporated in the vapor channel to control the switch status of the hot vapor flow. Experiments with such a thermal rectifier showed that a maximum thermal rectification ratio of 4.18 could be reached at the heat flux of 3222 W/m2, whereas a higher rectification ratio (up to 5.78) could even be achieved when forward and reversed heat transfer are at different heating temperatures in real applications. Besides, the forward thermal conductivity could reach 623 W/(m⋅K) for efficient waste heat harvest. In addition, the thermal rectification ratio, as well as the heating mode, can be tuned by the status of the valve in the tube loop to satisfy the complex requirement in practical applications.

Differences in human and sheep platelet adherence, aggregation and activation induced by glass beads in a modified chandler loop-system.

In human cardiovascular research, sheep in particular are used as a large animal model in addition to pigs. In these animals, medical products, developed and tested for human medical purposes, are almost exclusively used in interventional studies. Therefore, the extent to which platelets from human and ovine blood differ in terms of adherence, aggregation and activation after a 4- or 8-minutes exposure to glass was investigated. Testing was performed with platelet-rich plasma (PRP) and a modified chandler loop-system, with 4- and 8-minute blood-material exposure times corresponding to 20 and 40 test cycles, respectively, through the entire silicone tube loop of the test system.In sheep and human PRP, contact with the silicone tubing resulted in a decrease in platelet count after 4 minutes and 20 test cycles, respectively. Four more minutes (20 additional test cycles) caused a further decrease of the platelet count only in sheep PRP. When the silicon tube was partly filled with glass beads, these effects were more pronounced and stronger in sheep then in human PRP.The mean platelet volume, which was used as parameter for platelet aggregation, did not change over time in human PRP without glass exposure. With glass exposure in human and sheep PRP the mean platelet volume increased within 40 test cycles, but this increase was stronger in sheep than in human PRP.Regarding activation behavior, the activation markers CD62P and CD63 were detectable only in < 30% (sheep) and < 45% (human) of platelets, whereas after 8 min of glass exposure, the proportion of CD62P+ and CD63+ cells was more increased than before only in sheep. These results indicate that ovine platelets adhere more strongly to glass and show stronger aggregation behavior after glass contact than human platelets, but that ovine and human platelets differ only slightly in activability by glass.

Performance Tests on a Novel Un-Finned Thermosyphon Heat Exchanger Requiring a Single Charge

A novel design of an unfinned thermosyphon HPHX having a continuous closed tube loop which requires only a single charge is proposed for industrial waste heat recovery. The HPHX consists of 9×17 straight copper tubes in a staggered arrangement connected by 144 U bends. Without fins, not only are the pressure drops of the cooling air flow limited, but the cost, weight and maintenance effort can be greatly reduced. The thermal performance of this novel thermosyphon HPHX was tested with water at a filling ratio of 40%. The evaporator section is immersed in hot silicone oil, while the condenser section is cooled by air flow. The heat transfer rate (Q) reaches 6.65 kW at a heating pool temperature of 150 °C and a cooling air flow rate (F) of 1600 CMH, when the HPHX attains maximum effective thermal conductivity of 12,798 W/m-K. An ε-NTU theoretical model for single-tube thermosyphons was formulated with the boiling and film condensation modelled by empirical correlations. This model predicts the total resistance Rtot of the HPHX, which decreases with Q and F, with a total error of less than ±10%.

Technique of Ghost (Khatith) Ileostomy-How I Do It?

The concept of ghost/Khatith ileostomy is a bridge between covering ileostomy and no-ileostomy (‘Khatith’ meaning ‘hidden’ in Kashmiri language). We performed the pre-stage ghost ileostomy (GI) without parietal wall split. The technique of GI is that after the completion of resection-anastomosis of rectal cancer, a terminal ileal loop at about 20cm from ileocecal junction is identified. Small (10-12F) Ryle’s tube (RT) is passed through a small opening in the mesentery of the identified ileal loop. A small 4-5mm incision is given on abdominal wall at pre-operatively marked proposed stoma site in right iliac fossa region. Haemostatic Kelly’s forceps is introduced through this small incision to get out the two limbs of the RT that has been already looped around the identified ileal loop. These two limbs of the RT are cut short and fixed to each other and to the skin around it with 2-0 silk sutures, taking care to keep the tubing loop loose enough to avoid any tension to the vascular supply of the ileal loop and without causing any luminal compression of the loop to avoid bowel obstruction. In case of AL, the pre-stage GI can be converted into a formal covering stoma under local or spinal anesthesia by gentle pull of the two limbs of the looped RT to extract the isolated ileal loop through an adequate circular incision around the site of GI. In case of uncomplicated postoperative course, the fixing RT is pulled out gently from the abdominal cavity to release down the GI.

PEG J tube placement with optimization of J tube insertion.

We present a case series of 5 patients who underwent placement of a PEG tube followed by a J extension tube (PEG-J). PEG-J placement is usually performed as a 2-step procedure and is used for a variety of conditions such as gastroparesis. First, the PEG tube is placed using endoscopic transillumination, followed by tube placement with the pull method, and trimming of the PEG tube to approximately 20 cm. This is followed by insertion of the J extension tube through the PEG tube; the J extension tube is grasped by an endoscope and guided through the pylorus to a position distal to the ligament of Treitz. Two common problems related to the length of the PEG tube portion can occur when placing the J tube. A short PEG tube may not allow advancement of the J tube distal enough because of looping. On the other hand, a PEG tube that is too long can prevent adequate J tube insertion. Although the adverse events of PEG tubes are well documented, we did not find any published literature addressing problems with the placement of J tube extensions, although it is a frequently occurring problem in our clinical practice. Therefore, we have tried to address this problem. We present our technique for PEG-J tube placement, which allows optimal PEG tube length independent of the depth of J tube insertion. After PEG tube placement with the pull method, only the introducer is cut, and the entire length of the silicon PEG tube is left in situ. The tip of the J tube is lubricated and inserted into the PEG tube. In parallel, the J tube is grasped, in our cases with an endoclip, and gently maneuvered into the duodenum and eventually into the jejunum while the J tube is threaded into the PEG tube, matching the pull force from the J tube insertion by the endoscope. We use a pediatric colonoscope to achieve deep jejunal intubation; however, either the adult colonoscope or enteroscope are adequate alternative endoscopes. Once the J tube seal reaches the silicon portion of the PEG tube and further introduction is needed, a 5- to 10-cm portion of the silicon is cut using the sharp tip of the scissors provided with the PEG tube kit (Fig. 1). These steps of “peel and advance” are repeated until the J tube is advanced to the desired location and clipped to the jejunum mucosa. This technique allows optimal J tube placement without gastric looping or a too-short jejunal J tube insertion (Fig. 2). We followed all patients over 4 weeks. No PEG-J tube replacement adverse events were noted. Two patients had abdominal imaging at 4 weeks documenting optimal J tube placement without J tube loops or short J tubes resulting in proximal migration of the J tube (Video 1, available online at www.giejournal.org). All authors disclosed no financial relationships. https://www.videogie.org/cms/asset/9bec0238-72be-450f-8dbd-3862997703e4/mmc1.mp4Loading ... Download .mp4 (104.88 MB) Help with .mp4 files Video 1PEG-J tube placement with optimization of J tube insertion.

The coupling of reduced type H vessels with unloading-induced bone loss and the protection role of Panax quinquefolium saponin in the male mice.

Unloading-induced bone loss is a critical complication characterized by the imbalance of bone formation and resorption induced by long-term confinement in bed or spaceflight. CD31hiEmcnhi (type H) vessel is a specific subtype of capillary, which was coupled with osteogenesis. However, the change of type H vessel and its contributions to the unloading-induced bone loss remains undisclosed. Herein, we found that bone formation and the number of type H vessels were synchronously reduced in the hindlimb-unloading (HU) mice. Panax quinquefolium saponin (PQS) could increase bone mass, osteoblast function and the number of type H vessels in the HU mice. In vitro, PQS treatment accelerated HMECs migration, augmented the total tube loops and increased the secretion of VEGF and Noggin. Primary osteoblasts function was obviously increased when treated with supernatant from PQS-treated HMECs. These effects of PQS were substantially counteracted when VEGF and Noggin in HMECs were knocked down by siRNA. These results demonstrated that unloading-induced bone loss is coupled with reduction of type H vessels and PQS performs preventive function via promoting type H vessel angiogenesis, which is closely associated with endothelial cell-derived VEGF and Noggin.