A Polyvinyl Alcohol/Acrylamide Hydrogel with Enhanced Mechanical Properties Promotes Full-Thickness Skin Defect Healing by Regulating Immunomodulation and Angiogenesis Through Paracrine Secretion

Hydrogel-based tissue-engineered skin has attracted increased attention due to its potential to restore the structural integrity and functionality of skin.However,the mechanical properties of hydrogel scaffolds and natural skin are substantially different.Here,we developed a polyvinyl alcohol(PVA)/acrylamide based interpenetrating network(IPN)hydrogel that was surface modified with polydopamine(PDA)and termed Dopa-gel.The Dopa-gel exhibited mechanical properties similar to native skin tissue and a superior ability to modulate paracrine functions.Furthermore,a tough scaffold with tensile resistance was fabricated using this hydrogel by three-dimensional printing.The results showed that the interpenetration of PVA,alginate,and polyacrylamide networks notably enhanced the mechanical properties of the hydrogel.Surface modification with PDA endowed the hydrogels with increased secretion of immunomodulatory and proangiogenic factors.In an in vivo model,Dopa-gel treatment accelerated wound closure,increased vascularization,and promoted a shift in macrophages from a proinflammatory M1 phenotype to a prohealing and anti-inflammatory M2 phenotype within the wound area.Mechanistically,the focal adhesion kinase(FAK)/extracellular signal-related kinase(ERK)signaling pathway may mediate the promotion of skin defect healing by increasing paracrine secretion via the Dopa-gel.Additionally,proangiogenic factors can be induced through Rho-associated kinase-2(ROCK-2)/vascular endothelial growth factor(VEGF)-mediated paracrine secretion under tensile stress conditions.Taken together,these findings suggest that the multifunctional Dopa-gel,which has good mechanical properties similar to those of native skin tissue and enhanced immunomodulatory and angiogenic properties,is a promising scaffold for skin tissue regeneration.

Application of free vein skin flap on the anterior aspect of wrist in the case of finger injury with vessel and skin defect

Objective To introduce an effective reconstruction method for the finger injured with vessel and skin defect. Methods Free skin flap with skin vein was transplanted on the site of tissue defect, connecting by anastomosis the vein with artery or vein of the finger. Results Seven cases were treated with this method,among which 5 cases have sikin defect on the palm aspect of fingers, the rest have skin defect on the dorsal aspect skin of finger. All fingers survived with good shape and function. Conclusion This is a simple and effective method of finger reconstruction for the patients with defect of vessels and skin. 6 refs.

Repair of facial skin defect with a skin flap of SMAS pedicle

To report a method of repair facial skin defects with a skin flap of SMAS pedicle.Methods According to the size of defect of skin,design a skin flap with SMAS pedicle for repair of defect.Results The method has been successfully applied for skin defects of eyelid and lip in 14 cases with satisfied results.The area of the largest flap was 5 cm×3 cm.Conclusion Repairing facial defects such as eyelid skin defect or lip skin defect with skin flap of SMAS pedicle is a very good method.The flap has a good blood supporting and satisfactory color and flexibility.5 refs,6 figs.

Repair of necrosis and defects of penile skin with autologous free skin flap

We described a 27-year-old case of avulsion and traumatic degloving of penile with extensive penis skin necrosis. Under general anesthesia, donor skin was partially resected from lower limbs according to defect area of penile skin. Then shear the shape of graft was sheared, sutured to hostage skin defect and enswathed with tension. The postoperative appearance and function of the penis were satisfactory. It is suggest the homologous free skin flap from lower limbs is suitable for penile skin repair and beneficial to patient resulting in satisfactory erection and shape.

Subcutaneous pedicle Limberg flap for repairing skin defects in the face

Objective:To investigate the effect of a subcutaneous pedicle Limberg flap for the reconstruction of medium-sized skin defects in the face following skin tumor or scar excision. Methods: From August 2002 to June 2004,the subcutaneous pedicle Limberg flap was designed to repair facial skin defects in 17 patients(19 flaps),and the size of the lesions ranged from 2.0 cm×1.9 cm to 5.0 cm×4.5 cm.The operation was performed under general anesthesia in 2 children,and under local anesthesia in the remaining 15 patients. Results: All flaps survived with primary healing postoperatively.With a follow-up from 1 to 22 months,neither short-term nor long-term postoperative complications such as flap necrosis,hematoma,infection,visible dog-ear and trap door deformity were found,and functionally and cosmetically satisfactory outcomes were achieved. Conclusion: This subcutaneous pedicle Limberg flap provides a competitive repair alternative for the treatment of medium-sized skin defects in the face.

Bipedicled Mini V-Y Advancement Flap for Skin Defect of the Face

In young patients, even small circular facial defects after the excision of benign skin tumors present a reconstructive challenge. The usefulness of a V-Y advancement flap for reconstructing such defects is well documented. We refined this technique as a mini V-Y advancement flap consisting of two subcutaneous pedicles that vascularize the skin island via subdermal plexus lateral bridges. This technique was used for 21 middle-aged or younger patients with a small benign skin lesion. None of them experienced any postoperative complications. Aesthetically excellent results were found in all patients. This small advancement flap could be attempted as an alternative to fusiform excision of small skin lesions, particularly in younger patients.

Regenerative Medicine: A Review of Solutions in the Treatment of Skin Defects

The issue of skin defects is a major concern of almost every trauma surgeon after surgery. Despite numerous conventional methods and introduction of the reconstruction ladder, managing skin defects is still a challenge for the trauma surgeons. In recent years, parallel to the advances in the more conventional methods of skin repair, regenerative medicine has offered new and novel treatments. This article aims to explore these contemporary regenerative solutions as well as to review the conventional methods of treating skin defects.

Effects of hyperbaric oxygen therapy on 32 cases of full-thickness skin grafting for the repair of defects on the hand and foot

Full-thickness skin grafting is one of the most commonly used repair methods for skin defects. It has the advantage of wear-resistant with less scar hyperplasia and less difficult to operate with no symptoms. Hyperbaric oxygen was used in this study after full-thickness skin grafting from September 2012 to August 2016 to achieve the best effect of skin survival after surgery.

Artificial dermis combined with skin grafting for the treatment of hand skin and soft tissue defects and exposure of bone and tendon

BACKGROUND The recovery time of hand wounds is long,which can easily result in chronic and refractory wounds,making the wounds unable to be properly repaired.The treatment cycle is long,the cost is high,and it is prone to recurrence and disability.Double layer artificial dermis combined with autologous skin transplantation has been used to repair hypertrophic scars,deep burn wounds,exposed bone and tendon wounds,and post tumor wounds.AIM To investigate the therapeutic efficacy of autologous skin graft transplantation in conjunction with double-layer artificial dermis in treating finger skin wounds that are chronically refractory and soft tissue defects that expose bone and tendon.METHODS Sixty-eight chronic refractory patients with finger skin and soft tissue defects accompanied by bone and tendon exposure who were admitted from July 2021 to June 2022 were included in this study.The observation group was treated with double layer artificial dermis combined with autologous skin graft transplantation(n=49),while the control group was treated with pedicle skin flap transplantation(n=17).The treatment status of the two groups of patients was compared,including the time between surgeries and hospital stay.The survival rate of skin grafts/flaps and postoperative wound infections were evaluated using the Vancouver Scar Scale(VSS)for scar scoring at 6 mo after surgery,as well as the sensory injury grading method and two-point resolution test to assess the recovery of skin sensation at 6 mo.The satisfaction of the two groups of patients was also compared.RESULTS Wound healing time in the observation group was significantly longer than that in the control group(P<0.05,27.92±3.25 d vs 19.68±6.91 d);there was no significant difference in the survival rate of skin grafts/flaps between the two patient groups(P>0.05,95.1±5.0 vs 96.3±5.6).The interval between two surgeries(20.0±4.3 d)and hospital stay(21.0±10.1 d)in the observation group were both significantly shorter than those in the control group(27.5±9.3 d)and(28.4±17.7 d),respectively(P<0.05).In comparison to postoperative infection(23.5%)and subcutaneous hematoma(11.8%)in the control group,these were considerably lower at(10.2%)and(6.1%)in the observation group.When comparing the two patient groups at six months post-surgery,the excellent and good rate of sensory recovery(91.8%)was significantly higher in the observation group than in the control group(76.5%)(P<0.05).There was also no statistically significant difference in two point resolution(P>0.05).The VSS score in the observation group(2.91±1.36)was significantly lower than that in the control group(5.96±1.51),and group satisfaction was significantly higher(P<0.05,90.1±6.3 vs 76.3±5.2).CONCLUSION The combination of artificial dermis and autologous skin grafting for the treatment of hand tendon exposure wounds has a satisfactory therapeutic effect.It is a safe,effective,and easy to operate treatment method,which is worthy of clinical promotion.

Application of radial collateral artery perforator flap in severe posterior elbow skin defect

exposed wound of deep tissue behind elbow. Methods From April 2016 to December 2018, 28 patients with posterior elbow skin and soft tissue defect with exposed bone and tendon were treated in our hospital. the radial collateral artery perforator flap was used to repair the wound. There were 19 cases of skin defect with ulna exposure after electric shock injury, 5 cases of hot compression injury and 4 cases of bone exposure caused by skin contusion after traffic accident. Results There is no complication after the operation, all the flaps were survived. The flaps had good quality and satisfactory recovery of appearance and function. Conclusion The lateral upper arm flap designed by perforating branch of radial collateral artery is an effective method for posterior elbow skin and soft tissue defect because of its constant anatomic position and long vascular pedicle.

A novel microcurrent dressing for wound healing in a rat skin defect model

Background:The exogenous application of low-intensity electric stimulation(ES)may mimic a natural endogenous bioelectric current and accelerate the repair process of skin wounds.This study designed a novel microcurrent dressing(MCD)and evaluated its potential effects on wound healing in a rat skin defect model.Methods:First,wireless ES was integrated into a medical cotton cushion to fabricate the MCD,and its electrical property was examined by using a universal power meter.Then,animal experiments were conducted to evaluate the MCD’s effect.Forty-five rats were randomized into control(Con)group,Vaseline gauze(VG)group and MCD group.A full-thickness round skin incision 1.5 cm in diameter was made on the back of each animal.Apart from routine disinfection,the Con rats were untreated,whereas the other two groups were treated with VG or MCD.On days 3,7 and 14 post injury,the wound areas were observed and measured using image analysis software following photography,and the skin samples were harvested from wound tissue.Then,histopathological morphology was observed routinely by hematoxylin and eosin(HE)staining;tumor necrosis factorα(TNF-α)and interleukin(IL)-1βexpression were detected by Western blotting.Vascular endothelial growth factor(VEGF)and epidermal growth factor(EGF)expression were detected with immunohistochemistry.Results:The MCD generated a sf electric potential greater than 0.95 V.Animal experiments showed that the woundhealing rate in the MCD group was significantly increased compared with the Con and VG groups(P<0.05 or P<0.01).Histopathological observation revealed an alleviated inflammatory response,induced vascular proliferation and accelerated epithelization in the MCD group.Moreover,samples from the MCD group expressed reduced TNF-αand IL-1βlevels and increased VEGF and EGF levels compared with those of the other two groups(P<0.05 or P<0.01).However,no significant difference was noted between the Con and VG groups at each time point.Conclusions:The MCD generates a stable and lasting ES and significantly promotes wound healing by reducing inflammation duration and increasing growth factors expression.Thus,MCD may act as a promising biomaterial device for skin wound healing.

The improvement of living quality for the patient with carcinoma of esophagus: Reconstruction for the defect of pharynx and cervical esophagus with inferior antebrachial skin flap on the basis of retaining the laryngeal function

Objective To investigate the effect of reconstruction for inferior pharyngeal and cervical esophagus defect with inferior antebrachial skin flaps on the living quality of patients after surgery. Method Perform radical operation of the tumor, but retain larynx and trachea. Free antebrchial skin flaps were used to reconstruct the defect of inferior pharynx and cervical esophagus. Roll the skin flap to form a skin tube, and then carry out anastomosis with floor of mouth and cervical esophagus. Result The laryngeal function was retained after surgery. And permanent orifice of trachea was unnecessary. The effect was satisfying. The vocalization wasn’t affected and food-intake through oral was normal in the 2 patients followed up. Conclusion It is a feasible way to reconstruct the inferior pharynx and cervical esophagus defect caused by radical operation of the tumor at pharynx and cervical esophagus. It can improve the living quality of patients effectively.

Defect Engineering:Can it Mitigate Strong Coulomb Effect of Mg^(2+)in Cathode Materials for Rechargeable Magnesium Batteries?

Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.

Decade Milestone Advancement of Defect-Engineered g-C_(3)N_(4) for Solar Catalytic Applications

Over the past decade, graphitic carbon nitride(g-C_(3)N_(4)) has emerged as a universal photocatalyst toward various sustainable carbo-neutral technologies. Despite solar applications discrepancy, g-C_(3)N_(4) is still confronted with a general fatal issue of insufficient supply of thermodynamically active photocarriers due to its inferior solar harvesting ability and sluggish charge transfer dynamics. Fortunately, this could be significantly alleviated by the “all-in-one” defect engineering strategy, which enables a simultaneous amelioration of both textural uniqueness and intrinsic electronic band structures. To this end, we have summarized an unprecedently comprehensive discussion on defect controls including the vacancy/non-metallic dopant creation with optimized electronic band structure and electronic density, metallic doping with ultraactive coordinated environment(M–N_(x), M–C_(2)N_(2), M–O bonding), functional group grafting with optimized band structure, and promoted crystallinity with extended conjugation π system with weakened interlayered van der Waals interaction. Among them, the defect states induced by various defect types such as N vacancy, P/S/halogen dopants, and cyano group in boosting solar harvesting and accelerating photocarrier transfer have also been emphasized. More importantly, the shallow defect traps identified by femtosecond transient absorption spectra(fs-TAS) have also been highlighted. It is believed that this review would pave the way for future readers with a unique insight into a more precise defective g-C_(3)N_(4) “customization”, motivating more profound thinking and flourishing research outputs on g-C_(3)N_(4)-based photocatalysis.

Ultraconformable Integrated Wireless Charging Micro-Supercapacitor Skin

Conformable and wire-less charging energy storage devices play important roles in enabling the fast development of wearable,non-contact soft electronics.However,current wire-less charging power sources are still restricted by limited flexural angles and fragile connection of components,resulting in the failure expression of performance and constraining their fur-ther applications in health monitoring wearables and moveable artificial limbs.Herein,we present an ultracompatible skin-like integrated wireless charging micro-supercapacitor,which building blocks(including electrolyte,electrode and substrate)are all evaporated by liquid precursor.Owing to the infiltration and permeation of the liquid,each part of the integrated device attached firmly with each other,forming a compact and all-in-one configuration.In addition,benefitting from the controllable volume of electrode solution precursor,the electrode thickness is easily regulated varying from 11.7 to 112.5μm.This prepared thin IWC-MSC skin can fit well with curving human body,and could be wireless charged to store electricity into high capacitive micro-supercapacitors(11.39 F cm-3)of the integrated device.We believe this work will shed light on the construction of skin-attachable electronics and irregular sensing microrobots.

Impact Analysis of Microscopic Defect Types on the Macroscopic Crack Propagation in Sintered Silver Nanoparticles

Sintered silver nanoparticles(AgNPs)arewidely used in high-power electronics due to their exceptional properties.However,the material reliability is significantly affected by various microscopic defects.In this work,the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified,categorized,and quantified.Molecular dynamics(MD)simulations are employed to observe the failure evolution of different microscopic defects.The dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation motion.At the same time,this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain points.The impact of defect types on the failure process is also discussed.Furthermore,traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale model.The validity of the crack propagation model is confirmed through tensile tests.Finally,we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD model.Our findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.

Impact of Atrial Septal Defect Closure on Mortality in Older Patients

Background:Atrial septal defect(ASD)is a common form of adult congenital heart disease that can lead to long-term adverse outcomes if left untreated.Early closure of ASD has been associated with excellent outcomes and lower complication rates.However,there is limited evidence regarding the prognosis of ASD closure in older adults.This study aims to evaluate the mortality rates in older ASD patients with and without closure.Methods:A retrospective cohort study was conducted on patients aged 40 years or older with ASD between 2001 and 2017.Patients were followed up to assess all-cause mortality.Univariable and multivariable analyses were performed to identify the predictors of mortality.A p-value of<0.05 was considered statistically significant.Results:The cohort consisted of 450 patients(mean age 56.6±10.4 years,77.3%female),with 66%aged between 40 and 60 years,and 34%over 60 years.Within the cohort,299 underwent ASD closure(201 with transcatheter and 98 with surgical closure).During the median follow-up duration of 7.9 years,51 patients died.The unadjusted cumulative 10-year rate of mortality was 3%in patients with ASD closure,and 28%in patients without ASD closure(log-rank p<0.001).Multivariable analysis revealed that age(hazard ratio[HR]1.04,95%confidence interval[CI]1.006–1.06,p=0.01),NYHA class(HR 2.75,95%CI 1.63–4.62,p<0.001),blood urea nitrogen(BUN)(HR 1.07,95%CI 1.03–1.12,p<0.001),right ventricular systolic pressure(RVSP)(HR 1.07,95%CI 1.003–1.04,p=0.01),and lack of ASD closure(HR 15.12,95%CI 5.63–40.59,p<0.001)were independently associated with mortality.Conclusion:ASD closure demonstrated favorable outcomes in older patients.Age,NYHA class,BUN,RVSP,and lack of ASD closure were identified as independent factors linked to mortality in this population.

Sensitive skin syndrome: Research progress on mechanisms and applications

Sensitive skin is a clinical syndrome characterized by a hyper-reactive state of the skin,primarily on the face.It is accompanied by subjective symptoms such as burning,stinging,itching,and tightness when exposed to physical,chemical,or psychological stimuli.Objective signs,such as erythema,scales,and dilated blood vessels,may or may not be present.The discomfort associated with sensitive skin can be triggered by various endogenous and exogenous factors,which usually have no significant effect on the individual and do not induce irritant reactions.Sensitive skin often presents as a subjective state without clinical signs and exhibits diversity,posing challenges in sensitive skin research and care.This review summarizes the prevalence,key factors,pathophysiological mechanisms,diagnosis,and progress in daily care for sensitive skin.The aim is to provide a clearer and more systematic understanding of sensitive skin and offer guidance for sensitive skin care.

One-step approach for full-thickness skin defect reconstruction in rats using minced split-thickness skin grafts with Pelnac overlay

Background:Split-thickness skin grafting is the current gold standard for the treatment of traumatic skin loss.However,for patients with extensive burns,split-thickness skin grafting is limited by donor skin availability.Grafting split-thickness skin minced into micrografts increases the expansion ratio but may reduce wound repair quality.Dermal substitutes such as Pelnac can enhance the healing of full-thickness skin wounds,but their application currently requires two surgeries.The present study investigated whether it is possible to repair full-thickness skin defects and improve wound healing quality in a single surgery using Pelnac as an overlay of minced split-thickness skin grafts in a rat model.Methods:A full-thickness skin defect model was established using male Sprague-Dawley rats of 10 weeks old.The animals were randomly divided into control and experimental groups in which Vaseline gauze and Pelnac,respectively,were overlaid on minced split-thickness skin grafts to repair the defects.Wound healing rate and quality were compared between the two groups.For better illustration of the quality of wound healing,some results were compared with those obtained for normal skin of rats.Results:We found that using Pelnac as an overlay for minced split-thickness skin grafts accelerated wound closure and stimulated cell proliferation and tissue angiogenesis.In addition,this approach enhanced collagen synthesis and increased the formation of basement membrane and dermis as well as the expression of growth factors related to wound healing while reducing scar formation.Conclusions:Using minced split-thickness skin grafts overlaid with Pelnac enables the reconstruction of fullthickness skin defects in a single step and can increase the healing rate while improving the quality of wound healing.

Heterointerface Engineering-Induced Oxygen Defects for the Manganese Dissolution Inhibition in Aqueous Zinc Ion Batteries

Manganese-based material is a prospective cathode material for aqueous zinc ion batteries(ZIBs)by virtue of its high theoretical capacity,high operating voltage,and low price.However,the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be undesirable.In this work,heterointerface engineering-induced oxygen defects are introduced into heterostructure MnO_(2)(δa-MnO_(2))by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion batteries.Meanwhile,the heterointerface between the disordered amorphous and the crystalline MnO_(2)ofδa-MnO_(2)is decisive for the formation of oxygen defects.And the experimental results indicate that the manganese dissolution ofδa-MnO_(2)is considerably inhibited during the charge/discharge cycle.Theoretical analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn-O bonding state of the electrode material,thereby promoting electron transport kinetics as well as inhibiting Mn dissolution.Consequently,the capacity ofδa-MnO_(2)does not degrade after 100 cycles at a current density of 0.5 Ag^(-1)and also 91%capacity retention after 500cycles at 1 Ag^(-1).This study provides a promising insight into the development of high-performance manganese-based cathode materials through a facile and low-cost strategy.