Fallopian tube wrapping as a cause of catheter malfunction in peritoneal dialysis: a report of two cases and management strategies.

Background: Catheter malfunction is a common problem following the placement of a peritoneal dialysis (PD) catheter, and it is characterized by inadequate dialysate drainage, which can also limit infusion. Common causes include constipation, catheter migration, catheter kinking, omental wrapping, and fibrin obstruction. However, catheter obstruction by other intra-abdominal organs has been observed infrequently. Case Description: We present two cases of female PD patients experiencing catheter dysfunction after catheter implantation. The first case involves a 28-year-old female who suffered from problematic drainage and infusion of dialysate 1 month after catheter insertion, evidenced by catheter displacement from the pelvis on abdominal X-ray. The second case concerns a 49-year-old female PD patient who also encountered a bidirectional catheter malfunction 40 days post-implantation. Conservative methods failed to restore the catheter function in both patients. Laparoscopic examination revealed fallopian tube, not the omentum, was tightly wrapped around the PD catheter in both cases. Finally, laparoscopic surgery with catheter fixation restored the catheter function, enabling continued continuous ambulatory peritoneal dialysis (CAPD) with favorable outcomes. Conclusions: Our findings indicate that healthcare providers should consider fallopian tube wrapping as a potential cause of catheter dysfunction. Prompt consideration and utilization of laparoscopy with catheter fixation can play an important role in restoring catheter function and improving patient outcomes.

Specialized educational program for high-grade liver injury management: a three-dimensional printed model approach.

PURPOSE: The study aims to present a specialized educational program using a 3D printed model for managing Grade IV and V liver injuries. Hepatic packing, a common technique, may not always achieve sufficient hemostasis in these cases, warranting alternative solutions such as mesh liver wrapping. However, mastering this procedure is challenging due to limited teaching resources and the need for repeated practice. METHODS: A computer-based model was created from an abdominal CT scan to produce a real-sized injured liver model using thermoplastic elastomer TPU-95. Trainees received systematic instruction from an instructor, allowing them to perform the procedure under supervision and independently. RESULTS: Eight surgical residents at Hillel Yaffe Medical Center participated in the program, with the majority successfully completing the procedure under supervision. Furthermore, trainees demonstrated reduced procedure times when performing independently, indicating improved proficiency. CONCLUSION: This educational approach offers a simple and repeatable method for continuous training in managing high-grade liver injuries, holding potential for enhanced patient outcomes.

Multimodal management of ruptured internal carotid artery blood blister-like aneurysm: technical notes and case series of surgical muscle wrapping and fenestration clipping combined with flow-diverter embolization.

OBJECTIVE: To evaluate the effects of a multimodal management technique combining surgical muscle wrapping, clipping, and flow-diverter stent (FDS) placement in patients with ruptured blood blister-like aneurysms (BBAs) in the internal carotid artery (ICA). METHODS: In a retrospective case series review from 2020 to 2023, three patients with ruptured ICA BBAs underwent multimodal management, an approach combining muscle wrapping, surgical clipping, and FDS embolization. The aneurysm sac was initially packed and wrapped with multiple tailored temporalis muscle grafts and then secured using fenestration clips, with good preservation of the ICA branches. The FDS was placed 2-3 weeks after the clipping. RESULTS: All three patients had right ICA BBAs (mean age, 52 years). The modified Hunt and Hess grades ranged from 2 to 3, and the Fisher grades ranged from 3 to 4. The mean angiography follow-up time was 27.7 months (15, 31, and 37 months). There were no instances of symptomatic vasospasm or visible ischemic stroke during follow-up computed tomography. No patient required cerebrospinal fluid shunt implantation, and all achieved favorable neurological outcomes (modified Rankin Scale 0-1). Follow-up digital subtraction angiography revealed no evidence of aneurysm recurrence or significant ICA stenosis. CONCLUSIONS: We discuss a promising multimodal management approach for ruptured ICA BBAs combining muscle wrapping, surgical clipping, and FDS embolization. This technique was safe and effective in preventing re-rupture, achieving positive short-term clinical outcomes. Further research and more extensive studies are required to validate the long-term efficacy of this approach.

Tethered Particle Motion Analysis of DNA-Binding Properties of Architectural Proteins.

Architectural DNA-binding proteins are key to the organization and compaction of genomic DNA inside cells. Tethered particle motion (TPM) permits analysis of DNA conformation and detection of changes in conformation induced by such proteins at the single molecule level in vitro. As many individual protein-DNA complexes can be investigated in parallel, these experiments have high throughput. TPM is therefore well suited for characterization of the effects of protein-DNA stoichiometry and changes in physicochemical conditions (pH, osmolarity, and temperature). Here, we describe in detail how to perform tethered particle motion experiments on complexes between DNA and architectural proteins to determine their structural and biochemical characteristics.

Efficacy of the two-parts wrapping technique in reducing postoperative complications in laparoscopic pancreaticoduodenectomy.

BACKGROUND: The advancement of laparoscopic technology has broadened the application of laparoscopic pancreaticoduodenectomy (LPD) for treating pancreatic head and ampullary tumors. Despite its benefits, postoperative pancreatic fistula (POPF) and postpancreatectomy hemorrhage (PPH) remain significant complications. Ligamentum teres hepatis wrapping around the gastroduodenal artery (GDA) stump show limitations in reducing POPF and PPH. METHODS: This study retrospectively analyzed patients undergoing LPD from January 2016 to October 2023, We compared the effectiveness of the two-parts wrapping (the ligamentum teres hepatis wrapping of the gastroduodenal artery stump and the omentum flap wrapping of the pancreatojejunal anastomosis) and ligamentum teres hepatis wrapping around the gastroduodenal artery (GDA) in reducing postoperative pancreatic fistula (POPF) and postpancreatectomy hemorrhage (PPH), using propensity score matching for the analysis. RESULTS: A total of 172 patients were analyzed, showing that the two-parts wrapping group significantly reduced the rates of overall and severe complications, POPF, and PPH compared to ligamentum teres hepatis wrapping around the GDA group. Specifically, the study found lower rates of grade B/C POPF and no instances of PPH in the two-parts wrapping group, alongside shorter postoperative hospital stays and drainage removal times. These benefits were particularly notable in patients with soft pancreatic textures and pancreatic duct diameters of < 3 mm. CONCLUSION: The two-parts wrapping technique significantly reduce the risks of POPF and PPH in LPD, offering a promising approach for patients with soft pancreas and pancreatic duct diameter of < 3 mm.

Treatment of chronic and complex meniscal tears with arthroscopic meniscus repair augmented with collagen matrix wrapping: failure rate and functional outcomes.

PURPOSE: Meniscal wrapping is a fully arthroscopic technique that involves enhanced meniscal repair with a tissue-engineered collagen matrix wrapping. This study aims to investigate the feasibility of using the meniscal wrapping technique for the treatment of chronic or complex meniscal tears. The primary objective is to assess its failure rate. The secondary objectives are to analyse complication rate, functional outcomes and overall patient satisfaction. METHODS: This retrospective case series study included patients who sustained chronic and complex tears undergoing meniscal wrapping with autologous liquid bone marrow injection. Failure rate was considered if the patient underwent partial or complete meniscectomy or knee replacement during the follow-up, while other unexpected knee reoperations were considered as complications. Clinical outcomes were evaluated through the IKDC score, Tegner Activity Score and Short Assessment of Patient Satisfaction. RESULTS: Twenty-one patients were included (15 non-acute bucket-handle tears, three non-acute horizontal tears and three non-acute complex injuries). The failure rate was 9.5% at 33 months. The rate of other unplanned reoperations was 14.3%, but none of these complications were apparently directly related to the wrapping technique. The average postoperative IKDC was 73.3/100. No statistically significant difference was encountered between preinjury and postoperative Tegner Activity Score. The mean overall patient satisfaction was 88.3/100. CONCLUSIONS: Meniscal wrapping can be safely used as an adjunctive technique to meniscal repair in such difficult-to-treat cases to preserve the meniscus. The technique achieves a low failure rate and promising results of knee function, and patient satisfaction.

A Cell Pre-Wrapping Seeding Technique for Hydrogel-Based Tubular Organ-On-A-Chip.

Organ-on-a-chip (OOC) models based on microfluidic technology are increasingly used to obtain mechanistic insight into (patho)physiological processes in humans, and they hold great promise for application in drug development and regenerative medicine. Despite significant progress in OOC development, several limitations of conventional microfluidic devices pose challenges. First, most microfluidic systems have rectangular cross sections and flat walls, and therefore tubular/ curved structures, like blood vessels and nephrons, are not well represented. Second, polymers used as base materials for microfluidic devices are much stiffer than in vivo extracellular matrix (ECM). Finally, in current cell seeding methods, challenges exist regarding precise control over cell seeding location, unreachable spaces due to flow resistances, and restricted dimensions/geometries. To address these limitations, an alternative cell seeding technique and a corresponding workflow is introduced to create circular cross-sectioned tubular OOC models by pre-wrapping cells around sacrificial fiber templates. As a proof of concept, a perfusable renal proximal tubule-on-a-chip is demonstrated with a diameter as small as 50 µm, cellular tubular structures with branches and curvature, and a preliminary vascular-renal tubule interaction model. The cell pre-wrapping seeding technique promises to enable the construction of diverse physiological/pathological models, providing tubular OOC systems for mechanistic investigations and drug development.

A recombinant chimeric spider pyriform-aciniform silk with highly tunable mechanical performance.

Spider silks are natural protein-based biomaterials which are renowned for their mechanical properties and hold great promise for applications ranging from high-performance textiles to regenerative medicine. While some spiders can produce several different types of silks, most spider silk types - including pyriform and aciniform silks - are relatively unstudied. Pyriform and aciniform silks have distinct mechanical behavior and physicochemical properties, with materials produced using combinations of these silks currently unexplored. Here, we introduce an engineered chimeric fusion protein consisting of two repeat units of pyriform (Py) silk followed by two repeat units of aciniform (W) silk named Py2W2. This recombinant ∼86.5 kDa protein is amenable to expression and purification from Escherichia coli and exhibits high α-helicity in a fluorinated acid- and alcohol-based solution used to form a dope for wet-spinning. Wet-spinning enables continuous fiber production and post-spin stretching of the wet-spun fibers in air or following submersion in water or ethanol leads to increases in optical anisotropy, consistent with increased molecular alignment along the fiber axis. Mechanical properties of the fibers vary as a function of post-spin stretching condition, with the highest extensibility and strength observed in air-stretched and ethanol-treated fibers, respectively, with mechanics being superior to fibers spun from either constituent protein alone. Notably, the maximum extensibility obtained (∼157 ± 38 %) is of the same magnitude reported for natural flagelliform silks, the class of spider silk most associated with being stretchable. Interestingly, Py2W2 is also water-compatible, unlike its constituent Py2. Fiber-state secondary structure correlates well with the observed mechanical properties, with depleted α-helicity and increased ß-sheet content in cases of increased strength. Py2W2 fibers thus provide enhanced materials behavior in terms of their mechanics, tunability, and fiber properties, providing new directions for design and development of biomaterials suitable and tunable for disparate applications.

Internal valvuloplasty combined with sleeve wrapping in the treatment of severe great saphenous vein insufficiency: A report of two cases.

BACKGROUND: Great saphenous vein (GSV) valve incompetence is one of the most common manifestations of chronic venous insufficiency (CVI) in the lower limbs. There have been no reported attempts to repair the valve prior to the appearance of varicose morphology. METHOD: We describe two cases. Before surgery, the male patient had obvious pigmentation in the ankle area, and the female patient had obvious pain and swelling in the lower limbs after prolonged standing. Neither patient has obvious varicose veins. After retrograde venography, both patients were found to have severe reflux of the GSV valves (Kinster IV). We performed internal valvuloplasty and sleeve wrapping in two patients. RESULTS: After surgery, both patients had a significant improvement in symptoms and no particular complaints. Vascular ultrasound also suggested a good outcome. CONCLUSION: This surgery is safe and feasible in the treatment of early GSV incompetence, with good short-term results; long-term results remain to be seen.

Ultrathin and Deformable Graphene Etch Mask for Fabrication of 3D Microstructures.

Three-dimensional (3D) microfabrication techniques play a crucial role across various research fields. These techniques enable the creation of functional 3D structures on the microscale, unlocking possibilities for diverse applications. However, conventional fabrication methods have limits in producing complex 3D structures, which require numerous fabrication steps that increase the costs. Graphene is an atomically thin material known for its deformability and impermeability to small gases and molecules, including reactive gases like XeF2. These features make graphene a potential candidate as an etch mask for 3D microfabrication. Here, we report the fabrication of various 3D microstructures using graphene etch masks directly grown and patterned on a Si substrate. The patterned graphene deforms and wraps the etched structures, allowing for the fabrication of complicated 3D microstructures, such as mushroom-like and step-like microstructures. As a practical demonstration of the graphene etch mask, we fabricate an omniphobic surface of reentrant 3D structures on a Si substrate. Our work provides a method for fabricating complex 3D microstructures using a graphene etch mask, contributing to advancements in etching and fabrication processes.

Biologic Augmentation of Isolated Meniscal Repair.

PURPOSE OF REVIEW: The limited blood supply and intrinsic healing capacity of the meniscus contributes to suboptimal tissue regeneration following injury and surgical repair. Biologic augmentation techniques have been utilized in combination with isolated meniscal repair to improve tissue regeneration. Several innovative strategies such as Platelet-Rich Plasma (PRP), fibrin clots, mesenchymal stem cells (MSCs), bone marrow stimulation, meniscal scaffolds, and meniscal wrapping, are being explored to enhance repair outcomes. This article provides a comprehensive review of recent findings and conclusions regarding biologic augmentation techniques. RECENT FINDINGS: Studies on PRP reveal mixed outcomes, with some suggesting benefits in reducing failure rates of isolated meniscal repair, while others question its efficacy. Fibrin clots and PRF (Platelet-rich fibrin), although promising, show inconsistent results and lack sufficient evidence for definitive conclusions. MSCs demonstrate potential in preclinical studies, but clinical trials have been limited and inconclusive. Bone marrow stimulation appears effective in certain contexts, but its broader applicability remains uncertain. Meniscal scaffolds, including CMI (Collagen Meniscal Implants) and Actifit (polyurethane scaffolds), show encouraging short- and mid-term outcomes but have not consistently surpassed traditional methods in the long term. Meniscal wrapping is infrequently studied but demonstrates positive short-term results with certain applications. The review reveals a diverse range of outcomes for biologic augmentation in meniscal repair. While certain techniques show promise, particularly in specific scenarios, the overall efficacy of these methods has yet to reach a consensus. The review underscores the necessity for standardized, high-quality research to establish the definitive effectiveness of these biologic augmentation methods.

Analysis of the hemostatic effect of preset wrapping technique for type A aortic dissection with abnormal coagulation.

Background: There are many techniques to reduce anastomotic bleeding for the total arch replacement, but hemostasis is sometimes difficult to achieve after surgery for acute dissection, especially in patients with abnormal coagulation (AC). This study aimed to investigate the hemostatic effect and early efficacy of a pre-set bovine pericardium wrapper in the right heart system shunt for total arch replacement in patients with type A aortic dissection (TAAD) and preoperative AC. Methods: A retrospective analysis was conducted on 85 patients with TAAD and AC who underwent total arch replacement between January 2018 and December 2022. The patients were divided into two groups: the preset pericardium group (n=30) and the control group (n=55). Results: There were no significant differences between the two groups in terms of Bentall surgery (ascending aorta replacement with an aortic valve artificial vessel) and cardiac arrest time. However, compared to the control group, the preset pericardium group exhibited a shorter duration of cardiopulmonary bypass (CPB) and operation (P<0.001). Additionally, the preset pericardium group required fewer transfusions of blood products and hemostatic drugs (P<0.05). Moreover, the preset pericardium group had lower 24-hour postoperative mediastinal drainage volume (P<0.001), a lower proportion of bedside hemofiltration (P=0.039), and a shorter duration of mechanical ventilation and stay in the intensive care unit (P=0.014). Although the preset pericardium group showed reductions in in-hospital mortality, re-exploration for bleeding, and neurologic dysfunction, these differences were not statistically significant compared to the control group. Conclusions: This study represents the first investigation into the application of the preset wrapping technique in total arch replacement for TAAD with AC. The results demonstrate that this method can reduce the duration of CPB and operation, decrease postoperative bleeding, and minimize the need for blood transfusion and hemostatic drugs. Consequently, this technique may contribute to early postoperative recovery.

Role of Shape in Particle-Lipid Membrane Interactions: From Surfing to Full Engulfment.

Understanding and manipulating the interactions between foreign bodies and cell membranes during endo- and phagocytosis is of paramount importance, not only for the fate of living cells but also for numerous biomedical applications. This study aims to elucidate the role of variables such as anisotropic particle shape, curvature, orientation, membrane tension, and adhesive strength in this essential process using a minimal experimental biomimetic system comprising giant unilamellar vesicles and rod-like particles with different curvatures and aspect ratios. We find that the particle wrapping process is dictated by the balance between the elastic free energy penalty and adhesion free energy gain, leading to two distinct engulfment pathways, tip-first and side-first, emphasizing the significance of the particle orientation in determining the pathway. Moreover, our experimental results are consistent with theoretical predictions in a state diagram, showcasing how to control the wrapping pathway from surfing to partial to complete wrapping by the interplay between membrane tension and adhesive strength. At moderate particle concentrations, we observed the formation of rod clusters, which exhibited cooperative and sequential wrapping. Our study contributes to a comprehensive understanding of the mechanistic intricacies of endocytosis by highlighting how the interplay between the anisotropic particle shape, curvature, orientation, membrane tension, and adhesive strength can influence the engulfment pathway.

A Case of Symptomatic Multiple Tarlov Cysts Treated with Microsurgical Wrapping Technique -Efficacy and Limitation of Surgical Procedure.

Tarlov cysts (TCs) rarely cause clinical symptoms, such as leg pain, buttock pain, and bladder/bowel dysfunction. Surgery is considered when these symptoms persist despite medical treatments. Among several surgical procedures, microsurgical wrapping (MSW) is a relatively novel, simple technique with few complications, including cerebrospinal fluid leakage. Herein, we report a case of multiple TCs treated with MSW and present the mechanism of symptoms generated by TC and the procedure's limitations. A 58-year-old man complained of severe right leg and buttock pain for 3 months and was admitted to our hospital. His symptoms aggravated with sitting and standing and improved with the prone position. Spinal magnetic resonance imaging (MRI) demonstrated multiple sacral cysts containing intense cerebrospinal fluid. The cysts connect to the right S3 and S4 nerve roots. He was treated conservatively with medications; however, his symptoms were not improved. Therefore, MSW was performed for TCs connected to the S3 and S4 roots. The postoperative course was uneventful, and cerebrospinal fluid leakage did not occur. MRI performed 1 year after the operation demonstrated no recurrence of the TCs, and his leg pain was completely relieved; however, the buttock pain remained. MSW for TCs is effective for symptoms of adjacent nerve root compression; however, repairing the damaged nerve root in TCs is sometimes difficult. This may be a limitation of present surgical interventions because these symptoms may be difficult to treat even with other interventions.

Preparation and characterization of polyvinyl alcohol (PVA)-glycerol composite films incorporating nanosilica from municipal solid waste incinerator bottom ash.

This study investigates the fabrication of a composite film composed of polyvinyl alcohol (PVA) and glycerol, incorporating nanosilica derived from municipal solid waste incinerator bottom ash (BA). The nanosilica is blended with a PVA film-forming solution containing glycerol as a plasticizer. The composite films are characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Additionally, thermogravimetric analysis (TGA) is conducted to evaluate the thermal properties, while the mechanical properties are assessed in terms of tensile strength (TS) and elongation at break (EAB). The results indicate that the presence of silica nanoparticles reduces transparency and increases film thickness in the presence of glycerol. Notably, the film containing 1% silica demonstrates a significant enhancement in tensile strength, exhibiting a 50% increase compared to the film without silica. However, higher silica loadings lead to a deterioration in mechanical properties due to silica agglomeration within the polymer matrix. As expected, the presence of silica in the films slightly elevates the degradation temperature.

Sterile Instrument Storage in an Austere Environment: Are Sterile Peel Packaging and Cellulose Wrapping Equivalent?

BACKGROUND: Recommendations for optimal temperature and humidity for sterile instrument storage vary according to different sources. Furthermore, there are limited data comparing methods of packing smaller, lightweight, low-profile instruments. The purpose of this study was to compare sterile peel packaging and sterile cellulose wrapping for sterile instrument storage in an austere environment characterized by elevated temperature and humidity. METHODS: Stainless steel screws were sterilized and stored in either sterile peel packaging, sterile cellulose wrapping, or no packaging. Four groups were evaluated. Group 1 consisted of four screws in a sterile peelpack envelope and served as a time-zero control. Group 2 consisted of two groups of five screws, each packaged with blue sterilization cellulose wrap. Group 3 consisted of two groups of five screws, each packaged in sterile peel-pack envelopes. Group 4 consisted of 10 non-sterile unpackaged screws, which served as controls. Screws from groups 2, 3, and 4 were then cultured for 6 and 12 weeks. Temperature and humidity values were recorded in the instrument storage area. RESULTS: Average temperature was 21.3°C (SD 1.2°C; range 18.9°C-27.2°C) and average humidity was 51.7% (SD 3.9%; range 39%- 70%). Groups 1 (time-zero control) and 2 (sterile cellulose wrapping) demonstrated no growth. After 6 and 12 weeks, groups 3 (sterile peel packaging) and 4 (control) demonstrated bacterial growth. CONCLUSION: The most common culture isolates were gram-positive rods and two common nosocomial Staphylococcius species. Sterile peel packaging was not found to be equivalent to sterile cellulose wrapping in austere environmental conditions.

Efficacy of collagen conduit wrapping with collagen fibers on nerve regeneration in sciatic nerve injury with partial transection: An experimental study in the rat model.

Peripheral nerve injuries (PNIs) include complete and partial transection, crushing, and chronic compression injuries. Hollow absorbable conduits are used to treat complete transection with short defects, while wrapping the injured part with an absorbent material promotes nerve recovery by inhibiting inflammatory cell infiltration and scar tissue formation in crush injuries. For treatment of partially transected nerve injuries (PTNIs), such as injection-related iatrogenic PNI, whether wrapping the entire nerve, including the injury site, or bridging the transected fascicle with an artificial nerve conduit (ANC) is beneficial remains to be verified. The purpose of this study was to investigate whether wrapping the injured nerve and placing collagen fibers as scaffolds at the nerve defect site contribute to neural recovery in PTNI. A unilateral 5-mm partial nerve defect was created at the mid-thigh level in a rat sciatic nerve injury model. Fifty-four Sprague-Dawley (SD) rats (150-250 g) were divided into three groups (n = 9 each): group 1, collagen fibers were placed in the nerve defect and the sciatic nerve was wrapped with collagen conduit; group 2, the sciatic nerve was wrapped by collagen conduit without collagen fibers; and group 3, nerve defect was reconstructed with collagen-filled conduit. Nerve regeneration was evaluated by analyses of gait, electrophysiology, wet muscle weight, and axon numbers with immunohistochemistry at 12 and 24 weeks. Dorsiflexion angles among all groups improved significantly from 12 to 24 weeks postoperatively. At 24 weeks postoperatively, compound muscle action potential amplitudes (CMAPs) of tibialis anterior were 5.26 ± 4.64, 1.31 ± 1.17, and 0.14 ± 0.24 mV (p < .05), CMAPs of gastrocnemius were 21.3 ± 5.98, 15.4 ± 5.46, and 13.11 ± 3.91 mV in groups 1, 2, and 3, respectively; and the value of group 1 was significantly higher than that of group 3 (p < .05). Axon numbers were 2194 ± 629; 1106 ± 645; and 805 ± 907 in groups 1, 2, and 3, respectively (p < .05). For PTNI reconstruction, artificial nerve wrap (ANW) was superior to ANC. Providing collagen scaffold at the nerve defect site enhanced nerve recovery during reconstruction with ANW.

Visualization and Experimental Characterization of Wrapping Layer Using Planar Laser-Induced Fluorescence.

Droplets on nanotextured oil-impregnated surfaces have high mobility due to record-low contact angle hysteresis (∼1-3°), attributed to the absence of solid-liquid contact. Past studies have utilized the ultralow droplet adhesion on these surfaces to improve condensation, reduce hydrodynamic drag, and inhibit biofouling. Despite their promising utility, oil-impregnated surfaces are not fully embraced by industry because of the concern for lubricant depletion, the source of which has not been adequately studied. Here, we use planar laser-induced fluorescence (PLIF) to not only visualize the oil layer encapsulating the droplet (aka wrapping layer) but also measure its thickness since the wrapping layer contributes to lubricant depletion. Our PLIF visualization and experiments show that (a) due to the imbalance of interfacial forces at the three-phase contact line, silicone oil forms a wrapping layer on the outer surface of water droplets, (b) the thickness of the wrapping layer is nonuniform both in space and time, and (c) the time-average thickness of the wrapping layer is ∼50 ± 10 nm, a result that compares favorably with our scaling analysis (∼50 nm), which balances the curvature-induced capillary force with the intermolecular van der Waals forces. Our experiments show that, unlike silicone oil, mineral oil does not form a wrapping layer, an observation that can be exploited to mitigate oil depletion of nanotextured oil-impregnated surfaces. Besides advancing our mechanistic understanding of the wrapping oil layer dynamics, the insights gained from this work can be used to quantify the lubricant depletion rate by pendant droplets in dropwise condensation and water harvesting.

Inhibitor design for TMPRSS2: insights from computational analysis of its backbone hydrogen bonds using a simple descriptor.

Transmembrane protease serine 2 (TMPRSS2) is an important drug target due to its role in the infection mechanism of coronaviruses including SARS-CoV-2. Current understanding regarding the molecular mechanisms of known inhibitors and insights required for inhibitor design are limited. This study investigates the effect of inhibitor binding on the intramolecular backbone hydrogen bonds (BHBs) of TMPRSS2 using the concept of hydrogen bond wrapping, which is the phenomenon of stabilization of a hydrogen bond in a solvent environment as a result of being surrounded by non-polar groups. A molecular descriptor which quantifies the extent of wrapping around BHBs is introduced for this. First, virtual screening for TMPRSS2 inhibitors is performed by molecular docking using the program DOCK 6 with a Generalized Born surface area (GBSA) scoring function. The docking results are then analyzed using this descriptor and its relationship to the solvent-accessible surface area term ΔGsa of the GBSA score is demonstrated with machine learning regression and principal component analysis. The effect of binding of the inhibitors camostat, nafamostat, and 4-guanidinobenzoic acid (GBA) on the wrapping of important BHBs in TMPRSS2 is also studied using molecular dynamics. For BHBs with a large increase in wrapping groups due to these inhibitors, the radial distribution function of water revealed that certain residues involved in these BHBs, like Gln438, Asp440, and Ser441, undergo preferential desolvation. The findings offer valuable insights into the mechanisms of these inhibitors and may prove useful in the design of new inhibitors.

Signaling Pathways Controlling Axonal Wrapping in Drosophila.

The rapid transmission of action potentials is an important ability that enables efficient communication within the nervous system. Glial cells influence conduction velocity along axons by regulating the radial axonal diameter, providing electrical insulation as well as affecting the distribution of voltage-gated ion channels. Differentiation of these wrapping glial cells requires a complex set of neuron-glia interactions involving three basic mechanistic features. The glia must recognize the axon, grow around it, and eventually arrest its growth to form single or multiple axon wraps. This likely depends on the integration of numerous evolutionary conserved signaling and adhesion systems. Here, we summarize the mechanisms and underlying signaling pathways that control glial wrapping in Drosophila and compare those to the mechanisms that control glial differentiation in mammals. This analysis shows that Drosophila is a beneficial model to study the development of even complex structures like myelin.