Use of absorbable meshes in laparoscopic paraesophageal hernia repair

Paraesophageal hernia(PEH)repair is one of the most challenging upper gastrointestinal operations.Its high rate of recurrence is due mostly to the low quality of the crura and size of the hiatal defect.In an attempt to diminish the recurrence rates,some clinical investigators have begun performing meshreinforced cruroplasty with nonabsorbable meshes like polypropylene or polytetrafluoroethylene.The main problem with these materials is the occurrence,in some patients,of serious mesh-related morbidities,such as erosions into the stomach and the esophagus,some of which necessitate subsequent esophagectomy or gastrectomy.Absorbable meshes can be synthetic or biological and were introduced in recent years for PEH repair with the intent of diminishing the recurrence rates observed after primary repair alone but,theoretically,without the risks of morbidities presented by the nonabsorbable meshes.The current role of absorbable meshes in PEH repair is still under debate,since there are few data regarding their long-term efficacy,particularly in terms of recurrence rates,morbidity,need for revision,and quality of life.In this opinion review,we analyze all the presently available evidence of reinforced cruroplasty for PEH repair using nonabsorbable meshes(synthetic or biological),focusing particularly on recurrence rates,mesh-related morbidity,and long-term quality of life.

Successful occluding by absorbable sutures for epicardial collateral branch perforation

In order to improve the success rate of chronic total occlusion (CTO)percutaneous coronary intervention (PCI), retrograde approach has been attracted more attention.Recent study reported the collateral perforation rate was 6.9% in retrograde CTO PCI.[1,2] Collateral related perforations were higher in patients with the epicardial collateral than that with the septal collateral.[3]Several techniques have been developed to deal with the collateral branch perforation.Here,we described the treatment of epicardial collateral branch perforation by absorbable suture segments embolization through microcatheter during retrograde CTO PCI.

Synthetic Absorbable Surgical Sutures

This paper reviewed all types of the polymer - based synthetic absorbable surgical sutures that have been commercially produced. The chemical component, biological and mechanical properties, and using effect of these sutures were discussed. The recent development and the possible coming research orientation in these areas were also presented.

The Effects of Absorbable Materials in the Treatment for Non-Weight-Bearing Bone Fractures of Extremities

Objective:To study the effects of absorbable materials in non-weight-bearing bone fractures of extremities.Methods:After 66 patients with nonweight-bearing bone fractures of extremities were selected,absorbable materials were used in the observation group and metal materials were used in the control group.Results:After treatment,the bone healing in the observation group was significantly improved(P<0.05).Conclusion:the application of absorbable materials in non-weight-bearing bone fractures of extremities is effective.

Evaluation of the trauma and bone metabolism after internal absorbable screw and metal screw fixation treatment of tibia-fibula fracture

Objective:To study the trauma and bone metabolism after internal absorbable screw and metal screw fixation treatment of tibia-fibula fracture. Methods:78 patients with tibia-fibula fracture who received internal fixation surgery in our hospital between May 2013 and October 2015 were selected and randomly divided into absorbable group and metal group (n=39) who accepted internal absorbable screw fixation and internal metal screw fixation respectively. 3 d after operation, serum was collected to determine the levels of inflammatory factors, pain mediators, stress hormones and bone metabolism indexes. Results: Serum inflammatory mediators procalcitonin (PCT), Resistin, C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α(TNF-α), pain mediators substance P (SP), prostaglandin E2 (PGE2) and NPY, stress hormones norepinephrine (NE), epinephrine (E) and cortisol (Cor) as well as bone resorption marker molecules C-terminal telopeptides of type I collagen (CTX-I) and C-terminal telopeptides of type II collagen (CTX-II) levels of absorbable group were significantly lower than those of metal group (P<0.05) while bone formation marker molecules N-MID osteocalcin (N-MID) and N-terminal propeptide of procollagen type I (PINP) levels were significantly higher than those of metal group (P<0.05). Conclusions:The trauma degree of internal absorbable screw fixation treatment of tibia-fibula fracture is weaker than that of internal metal screw fixation, and the bone metabolism activity is better than that of internal metal screw fixation.

Degradability of absorbable sutures in tendon grafts following anterior cruciate ligament reconstruction

Objective To observe the degradability of absorbable sutures in tendon grafts and the histology of tendon healing in a rabbit model.Methods Semitendinosus tendons were harvested from 15 healthy adult New Zealand rabbits in this study.

Absorbable magnesium-based stent: physiological factors to consider for in vitro degradation assessments

Absorbable metals have been widely tested in various in vitro settings using cells to evaluate their possible suitability as an implant material.However,there exists a gap between in vivo and in vitro test results for absorbable materials.A lot of traditional in vitro assessments for permanent materials are no longer applicable to absorbable metallic implants.A key step is to identify and test the relevant microenvironment and parameters in test systems,which should be adapted according to the specific application.New test methods are necessary to reduce the difference between in vivo and in vitro test results and provide more accurate information to better understand absorbable metallic implants.In this investigative review,we strive to summarize the latest test methods for characterizing absorbable magnesium-based stent for bioabsorption/biodegradation behavior in the mimicking vascular environments.Also,this article comprehensively discusses the direction of test standardization for absorbable stents to paint a more accurate picture of the in vivo condition around implants to determine the most important parameters and their dynamic interactions.

Potential bioactive coating system for high-performance absorbable magnesium bone implants

Magnesium alloys are considered the most suitable absorbable metals for bone fracture fixation implants.The main challenge in absorbable magnesium alloys is their high corrosion/degradation rate that needs to be controlled.Various coatings have been applied to magnesium alloys to slow down their corrosion rates to match their corrosion rate to the regeneration rate of the bone fracture.In this review,a bioactive coating is proposed to slow down the corrosion rate of magnesium alloys and accelerate the bone fracture healing process.The main aim of the bioactive coatings is to enhance the direct attachment of living tissues and thereby facilitate osteoconduction.Hydroxyapatite,collagen type I,recombinant human bone morphogenetic proteins 2,simvastatin,zoledronate,and strontium are six bioactive agents that show high potential for developing a bioactive coating system for high-performance absorbable magnesium bone implants.In addition to coating,the substrate itself can be made bioactive by alloying magnesium with calcium,zinc,copper,and manganese that were found to promote bone regeneration.

Multiphase Interfacial Regulation Based on Hierarchical Porous Molybdenum Selenide to Build Anticorrosive and Multiband Tailorable Absorbers

Electromagnetic wave(EMW)absorbing materials have an irreplaceable position in the field of military stealth as well as in the field of electromagnetic pollution control.And in order to cope with the complex electromagnetic environment,the design of multifunctional and multiband high efficiency EMW absorbers remains a tremendous challenge.In this work,we designed a three-dimensional porous structure via the salt melt synthesis strategy to optimize the impedance matching of the absorber.Also,through interfacial engineering,a molybdenum carbide transition layer was introduced between the molybdenum selenide nanoparticles and the three-dimensional porous carbon matrix to improve the absorption behavior of the absorber.The analysis indicates that the number and components of the heterogeneous interfaces have a significant impact on the EMW absorption performance of the absorber due to mechanisms such as interfacial polarization and conduction loss introduced by interfacial engineering.Wherein,the prepared MoSe_(2)/MoC/PNC composites showed excellent EMW absorption performance in C,X,and Ku bands,especially exhibiting a reflection loss of−59.09 dB and an effective absorption bandwidth of 6.96 GHz at 1.9 mm.The coordination between structure and components endows the absorber with strong absorption,broad bandwidth,thin thickness,and multi-frequency absorption characteristics.Remarkably,it can effectively reinforce the marine anticorrosion property of the epoxy resin coating on Q235 steel substrate.This study contributes to a deeper understanding of the relationship between interfacial engineering and the performance of EMW absorbers,and provides a reference for the design of multifunctional,multiband EMW absorption materials.

Optical Nonlinearity of Violet Phosphorus and Applications in Fiber Lasers

A D-shaped fiber is coated with a new two-dimensional nanomaterial,violet phosphorus(VP),to create a saturable absorber(SA)with a modulation depth of 3.68%.Subsequently,the SA is inserted into a fiber laser,enabling successful generation of dark solitons and bright–dark soliton pairs through adjustment of the polarization state within the cavity.Through further study,mode-locked pulses are achieved,proving the existence of polarization-locked vector solitons.The results indicate that VP can be used as a polarization-independent SA.

A flexible ultra-broadband multi-layered absorber working at 2 GHz-40 GHz printed by resistive ink

A flexible extra broadband metamaterial absorber(MMA)stacked with five layers working at 2 GHz–40 GHz is investigated.Each layer is composed of polyvinyl chloride(PVC),polyimide(PI),and a frequency selective surface(FSS),which is printed on PI using conductive ink.To investigate this absorber,both one-dimensional analogous circuit analysis and three-dimensional full-wave simulation based on a physical model are provided.Various crucial electromagnetic properties,such as absorption,effective impedance,complex permittivity and permeability,electric current distribution and magnetic field distribution at resonant peak points,are studied in detail.Analysis shows that the working frequency of this absorber covers entire S,C,X,Ku,K and Ka bands with a minimum thickness of 0.098λ_(max)(λ_(max) is the maximum wavelength in the absorption band),and the fractional bandwidth(FBW)reaches 181.1%.Moreover,the reflection coefficient is less than-10 dB at 1.998 GHz–40.056 GHz at normal incidence,and the absorptivity of the plane wave is greater than 80%when the incident angle is smaller than 50°.Furthermore,the proposed absorber is experimentally validated,and the experimental results show good agreement with the simulation results,which demonstrates the potential applicability of this absorber at 2 GHz–40 GHz.

Study of relationship between motion of mechanisms in gas operated weapon and its shock absorber

The article deals with the motion of the breech block carrier and the weapon casing of an automatic weapon mounted on a flexible carriage and the base of the weapon.Earlier works,which did not consider the dynamic properties of the base of the weapon,did not allow to reconcile the calculated and experimental results of the weapon casing displacement when shooting from firing rests.For the analysis of the motion of individual parts,the methods of mathematical modelling and firing experiments using a high-speed camera were chosen.Calculations show the best accord with experiment when modelling the system with 4 degrees of freedom.The oscillation of the system regarding the movement of the breech block carrier and the weapon casing was investigated under changed conditions of rate of fire,the use of a muzzle brake and different types of shock absorbers.The velocities and displacements of the weapon casing and the breech block carrier at different values of the impulse of the gases to the breech block carrier were determined.

Preparation and Swelling Kinetic Analysis of Poly (HPMC-co-AA-co-AM) Super Absorbent Resin

Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.

A low-profile metamaterial absorber with ultrawideband reflectionless and wide-angular stability

An ultrawideband reflectionless metamaterial absorber(MA)is proposed by replacing the metallic ground with the complementary split-ring resonator(CSRR)structure.The proposed MA exhibits-10 d B reflectivity spectrum from 1 GHz to 20 GHz,which maintains more than 90%absorption from 1.5 GHz to20 GHz.Furthermore,it achieves angle stability for TE and TM polarization at oblique incident angles up to 40°and 65°,respectively.To achieve broadband absorption spectrum,we have adopted a single-layer high-impedance surface(HIS)loaded with a double-layer magnetic material(MM)structure.To further realize the RCS reduction into a lower frequency range,we have employed the scattering cancellation technology into the traditional metallic ground.Finally,we have fabricated a sample exhibiting the 10 d B RCS reduction from 1 GHz to 20 GHz with a thickness of 10 mm.Measurement and simulation results confirm that the proposed MA exhibits excellent comprehensive performance,making it suitable for many practical applications.

Measurement of Radon Concentration and Estimation of Cancer Risk in Twenty-Four Model Houses in the Town of Koudougou

The objective of our study is to evaluate the concentration of radon (86Rn) inside houses in the town of Koudougou in order to estimate its impact on the health of the population. Indeed, when uranium-rich minerals are found near the surface of the ground, radon concentrations can reach tens of becquerels per cubic meter in enclosed spaces. Given the nature of the geological base of Burkina Faso, this situation is quite probable and certain places that are sometimes poorly ventilated (house, school, office, etc.) can have radon levels high enough to constitute a health problem for occupants. Thus, twenty-four (24) sample houses were identified. In each house, the Corentium digital detector was between 0.8 m and 2 m for at least one week in a place where the occupants estimate that they spend more time of time and measure the concentration of radon in the long term and short term. The recorded data allowed us to determine the Absorbed Dose and the Annual Effective Dose of radon gas for each house in order to estimate the Risk of Cancer and the probable Number of Cases of Lung Cancer per million inhabitants. Thus, the results indicate that the long-term radon concentration varies between 6 Bq/m3 and 285 Bq/m3 respectively in houses 11 and 4 compared to 1 Bq/m3 to 208 Bq/m3 in the short term in the same houses. Also, in the long term, in control houses 1, 3 and 4, the radon level is above the recommended threshold interval. For the short term, these are houses 1, 3, 4 and 17 respectively with 110 Bq/m3, 142 Bq/m3, 208 Bq/m3 and 105 Bq/m3. As for the long-term and short-term effective doses, only houses 1, 3, 4, 17 and 24 have values between 3 - 10 Sv/year. The estimation of the relative risk of lung cancer gives values relatively close to unity and between 1.006 and 1.142 with an average of 1.035 and that of the Number of Lung Cancer Cases per million inhabitants gives values between 8 and 166 with an average of 42. Thus, we can conclude that with the exception of houses 1, 3, 4 and 17, the radon concentrations are relatively low in the twenty-four control houses in the city of Koudougou. The lifestyle of the populations can well explain this situation when we know that people are in the habit of always leaving doors and windows open, especially when they are not sleeping. We can therefore say that the risk of population exposure to radon gas is relatively low in the town of Koudougou.

Research on the Damping Mechanism of Time-Delay Coupled Negative Stiffness Dynamic Absorber in Nonlinear Vibration Damping System

A study was conducted on the effect of time delay and structural parameters on the vibration reduction of a time delayed coupled negative stiffness dynamic absorber in nonlinear vibration reduction systems. Taking dynamic absorbers with different structural and control parameters as examples, the effects of third-order nonlinear coefficients, time-delay control parameters, and negative stiffness coefficients on reducing the replication of the main system were discussed. The nonlinear dynamic absorber has a very good vibration reduction effect at the resonance point of the main system and a nearby area, and when 1 increases to a certain level, the stable region of the system continues to increase. The amplitude curve of the main system of a nonlinear dynamic absorber will generate Hop bifurcation and saddle node bifurcation in the region far from the resonance point, resulting in almost periodic motion and jumping phenomena in the system. For nonlinear dynamic absorbers with determined structural parameters, time-delay feedback control can be adopted to control the amplitude of the main system. For different negative stiffness coefficients, there exists a minimum damping point for the amplitude of the main system under the determined system structural parameters and time-delay feedback control parameters.

Photometric analysis of absorbable barbed suture for periareolar closure in mastopexy

Aim:The primary author previously described his technique for periareolar closure in mastopexy using a pinwheel interlocking purse string with absorbable barbed suture and now reports the results of a retrospective photometric analysis comparing this technique with the same closure using Gortex®suture.This study is designed to compare the degree of areolar widening and safety profile of using absorbable barbed sutures for periareolar closure versus permanent smooth suture.Methods:A retrospective chart review was conducted of all patients whose periareolar closures were performed using an interlocking purse-string technique over a 10-year period.Only patients undergoing circumvertical mastopexy were included.All had photometric evaluation and follow-up performed within 6-24 months.Results:In total,20 patients(40 areolas),which were closed with absorbable barbed suture,were analyzed photometrically.In this suture group,areola size increased a mean of 4.9%from baseline,and no complications(0%)were observed.This compared favorably with previously reported complication rates using permanent sutures and with a series of cases presented herein in which permanent smooth suture was used for purse string closure.The degree to which absorbable barbed suture controls areolar spread was shown to be significantly better than those where permanent smooth purse string techniques were employed.Conclusion:Circumvertical mastopexy closures using absorbable barbed suture was shown to be safe and effective and compared favorably to older techniques using permanent smooth suture for similar closures.This paper lends support to the safety of using absorbable barbed suture in circumareolar closures to limit areolar spread.

Comperative analysis of unilateral cleft lip closure using absorbable and nonabsorbable sutures: a randomised clinical study

Aim:Patients with cleft lip usually undergo multiple procedures that require hospitalization resulting in emotional stress to their family members.Young patients often require sedation or general anesthesia(GA)for suture removal on a sensitive area to prevent disruption of the repair.In this study,we compared absorbable and nonabsorbable sutures for primary cleft lip repair.Methods:Patients with cleft lip who presented to Smile Train Unit,Child Hospital and Research Institute,Nagpur,India,were randomly assigned to two groups and underwent surgical repair using either Vicryl Rapid suture(Group 1)or Prolene suture(Group 2).Patients were followed up at 1 month,6 months,and 1 year.Photographs of the patients were obtained at these visits and rated using a validated 100-mm cosmesis visual analogue scale(VAS)by three people(social worker,surgeon,and patient’s mother).A VAS score of 15 mm or greater was considered as clinically important difference.Results:A total of 60 patients were enrolled in this study,and they were equally divided into two groups.There was no difference in age,race,sex,wound length,number of sutures,and layered repair rates between the groups.The average age of the patient was 3 months.There was no significant difference in the rates of infection which was 6%in this study,wound dehiscence,and hypertrophic scar formation.No significant difference was found in cosmetic outcome in both the mean VAS score of 90.3 in Group 1 and 91.7 in Group 2.Conclusion:Absorbable sutures are a viable alternative to nonabsorbable sutures in the repair of primary cleft lip repair.We prefer absorbable sutures because they do not require removal under GA or sedation.

Enhanced Microwave Absorption for High Filler Content Composite Molded from Polymer Coated Flaky Carbonyl Irons Modified by Silane Coupling Agents

A microwave absorbing sheet with a high complex permeability and a relatively low complex permittivity is obtained by molding of the densely coated flaky carbonyl iron particles(FCIPs)by styrenebutadiene-styrene block copolymer(SBS)in the assistance of coupling agent modification.Direct molding of the core-shell FCIPs without adding extra binder results in a large permeability due to the high filling ratio(55vol%)of absorbents.Importantly,the permittivity is well suppressed by the dense insulate polymer shell on the FCIPs,avoiding the severe impedance mismatch problem of the high filler content microwave absorbing materials.Investigations show that modifying the surface of FCIPs by proper amount of silane coupling agent is critical for the coating quality of the SBS shell,which is verified by resistivity and corrosion current density measurements,and can be interpreted by improved interfacial compatibility between the modified FCIPs and SBS.The obtained microwave absorbing sheet shows a minimum reflection loss of-38.74 dB at 1.57 GHz and has an effective absorption bandwidth from 1.1 to 2.3 GHz at a relatively small thickness of 2 mm.

Enhanced microwave absorption property of silver decorated biomass ordered porous carbon composite materials with frequency selective surface incorporation

Porous carbon(PC)is a promising electromagnetic(EM)wave absorbing material thanks to its light weight,large specific surface area as well as good dissipating capacity.To further improve its microwave absorbing performance,silver coated porous carbon(Ag@PC)is synthesized by one-step hydro-thermal synthesis process making use of fir as a biomass formwork.Phase compositions,morphological structure,and microwave absorption capability of the Ag@PC has been explored.Research results show that the metallic Ag was successfully reduced and the particles are evenly distributed inward the pores of the carbon formwork,which accelerates graphitization process of the amorphous carbon.The Ag@PC composite without adding polyvinyl pyrrolidone(PVP)exhibits higher dielectric constant and better EM wave dissipating capability.This is because the larger particles of Ag give rise to higher electric conductivity.After combing with frequency selective surface(FSS),the EM wave absorbing performance is further improved and the frequency region below-10 d B is located in8.20-11.75 GHz,and the minimal reflection loss value is-22.5 dB.This work indicates that incorporating metallic Ag particles and FSS provides a valid way to strengthen EM wave absorbing capacity of PC material.