ABSTRACT
PURPOSE: To explore associations among psychological resilience, self-esteem, social support, and non-suicidal self-injury (NSSI) behaviors in adolescents receiving inpatient psychiatric care. METHOD: In this cross-sectional study, 505 Chinese adolescents (aged 10 to 19 years) receiving inpatient psychiatric care completed a general characteristics questionnaire, the Psychological Resilience Scale (PRS), Self-Esteem Scale (SES), and Child and Adolescent Social Support Scale (CASSS). Statistical tests were used to compare NSSI incidence, scale scores, and factors influencing NSSI. RESULTS: The incidence rate of NSSI was 77.82% (n = 393). Total and dimension scores on the PRS, SES, and CASSS in the NSSI group were significantly lower than those in the non-NSSI group (p < 0.01). Binary logistic multifactorial regression analysis showed that participants who were female and aged 10 to 14 years were more prone to NSSI behavior (p < 0.05). Having close friends, high parental expectations, and moderate to high self-esteem were protective factors for NSSI behavior (p < 0.05). CONCLUSION: Nursing personnel should prioritize enhancing psychological resilience, self-esteem, and social support in adolescents receiving inpatient psychiatric care to mitigate the risk of NSSI and ensure the safety of hospitalized individuals. [Journal of Psychosocial Nursing and Mental Health Services, 62(9), 47-54.].
Subject(s)
Resilience, Psychological , Self Concept , Self-Injurious Behavior , Social Support , Humans , Adolescent , Female , Self-Injurious Behavior/psychology , Male , Cross-Sectional Studies , Child , Surveys and Questionnaires , Inpatients/psychology , Adolescent Behavior/psychology , Young AdultABSTRACT
Drug-resistant biofilm infection is an extremely serious clinical problem, that easily leads to failure of antibiotic treatment. Although gold nanoparticles (AuNPs) as photothermal agents have been widely used in biofilm eradication, there are still challenges to be addressed, such as insignificantly redshifted absorption and slow assembly process of aggregated AuNPs. Herein, we developed an acidity-activated dispersion-to-aggregation transition to enhance the accumulation of self-complementary zwitterionic peptide-decorated AuNPs for photothermal eradication of drug-resistant biofilm infections. AuNPs were decorated with self-complementary zwitterionic peptides (ZP1 and ZP2) coupled with pH-sensitive anhydride (DMA) and pH-insensitive anhydride (SA), respectively. ZP2-decorated AuNPs with DMA modification (AuNP@ZP2(DMA)) exhibited prolonged blood circulation and enhanced accumulation in acidic biofilm microenvironment. Moreover, the electrostatic attraction between self-complementary ligands drove AuNPs to form closely packed aggregates with strong near-infrared absorption, leading to in vivo photoacoustic imaging ability and photothermal effect against drug-resistant bacteria and fungus, as well as microbial biofilms. AuNP@ZP2(DMA) with longer charge domains and a polyethylene glycol oligomer spacer showed greater photothermal antimicrobial and biofilm resistance in vitro and in vivo. This study develops an innovative acidity-activated AuNP photothermal agent, which provides an effective approach for treatment of biofilm infections.
Subject(s)
Gold , Metal Nanoparticles , Gold/pharmacology , Gold/chemistry , Metal Nanoparticles/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Biofilms , Anhydrides/pharmacologyABSTRACT
The proton exchange membrane (PEM) fuel cell is a device that demonstrates a significant potential for environmental sustainability, since it efficiently converts chemical energy into electrical energy. The microporous layer (MPL) in PEM fuel cells promotes gas transport and eliminates water. Nevertheless, the power density of PEM fuel cells is restricted by ohmic losses and mass transport losses in conventional MPLs. In this study, we enhanced the power density of proton exchange membrane (PEM) fuel cells through the identification of appropriate materials and the mitigation of mass transport losses occurring at the interface between the microporous layer and the catalyst layer. The incorporation of high electron conductivity, slip behavior at the interface between graphene and water, and rapid water evaporation facilitated by nanoporous graphene effectively address transport-related challenges. We evaluated two types of graphene as potential substitutes for carbon black in the microporous layer (MPL). The enhanced power density (up to 1.1 W cm-2) under all humidity conditions and reduced mass transport resistance (a 75 % reduction compared to carbon black MPL) make them promising candidates for next-generation PEM fuel cells. Furthermore, these findings provide guidance for controlling interfacial mass transport in colloidal systems.
ABSTRACT
Proton exchange membrane (PEM) fuel cells are a promising and environmentally friendly device to directly convert hydrogen energy into electric energy. However, water flooding and gas transport losses degrade its power density owing to structural issues (cracks, roughness, etc.) of the microporous layer (MPL). Here, we introduce a green material, supercritical fluid exfoliated graphene (s-Gr), to act as a network to effectively improve gas transport and water management. The assembled PEM fuel cell achieves a power density of 1.12 W cm-2. This improved performance is attributed to the reduction of cracks and the slip of water and gas on the s-Gr surface, in great contrast to the nonslip behavior on carbon black (CB). These findings open up an avenue to solve the water and gas transport problem in porous media by materials design with low friction and provide a new opportunity to boost high power density PEM fuel cells.
ABSTRACT
Background: Non-suicidal self-injury (NSSI) is a major public health concern among adolescents. Further research is needed into contributors to this behavior, in particular among adolescents with psychiatric disorders. The aim of the present study was to explore the impact of life events and emotional stress on NSSI among hospitalized psychiatric adolescents. Methods: In this cross-sectional study, 505 Chinese psychiatric adolescent inpatients 10-19 years old completed questionnaires about sociodemographic characteristics and NSSI as well as the Adolescent Self-Rating Life Events Checklist (ASLEC), the State-Trait Anxiety Inventory Form Y, and the Center for Epidemiological Studies Depression Scale. Chi-square test was used to compare the incidence of NSSI in psychiatric adolescent patients with different sociodemographic. T-test was used to compare the total scores and dimension scores of the ASLEC, STAI-Y, and CES-D between the NSSI group and the non-NSSI group. A binary logistic regression model was built to explore the relationships among sociodemographic characteristics, questionnaire scores and NSSI. Results: Most psychiatric adolescent inpatients (393, 77.8%) reported NSSI behavior. The higher risk for NSSI was observed among female (odds ratio [OR] 2.665, 95% confidence interval [CI] 1.575-4.510), younger adolescents (10-14 years; OR 2.021, 95% CI 1.258-3.245), with a suicide history (OR 2.479, 95% CI 1.549-3.967), or with depression symptom (OR 3.217, 95% CI 1.572-6.582) and those with higher scores of ASLEC (OR 1.019, 95% CI 1.010-1.029). Conclusion: Our study in China is one of the first to apply to adolescent inpatients the diagnostic criteria of NSSI in the latest edition of the Diagnostic and Statistical Manual of Mental Disorders. Our analysis suggests that NSSI prevalence is disturbingly high among adolescents with mental illness in China. A better understanding of contributing factors, especially negative life events and negative emotions, may guide interventions that can reduce its prevalence.
ABSTRACT
Background: Myocardial ischemia-reperfusion is a common pathological feature of many heart and vascular diseases, but the molecular mechanism of this process is still unclear, and there is no effective way to protect cardiomyocytes. The aim of this study was to examine the effects and underlying molecular mechanisms of Lycium barbarum polysaccharide (LBP) on myocardial ischemia-reperfusion injury in cardiomyocytes. Methods: The cardiomyocyte cell line H9c2 were used to establish an in vitro hypoxia/reoxygenation (H/R) model. After treatment with LBP and/or the SIRT3 inhibitor 3-TYP, cell morphology was observed under the light microscopy. The Cell Counting Kit (CCK)-8 and 5-ethynyl-2'-deoxyuridine (EdU) assay were used to detect cell proliferation, and flow cytometry was performed to assess cell apoptosis. The lysine (166)-acetylation of CypD1 was determined by co-immunoprecipitation assay. Enzyme-linked immunosorbent assay (ELISA) was used to determine the lactate dehydrogenase (LDH) level in the culture medium. Na+-K+-ATPase activity, Ca2+-ATPase activity, and nitric oxide (NO) levels were measured. Results: LBP alleviated cell damage and upregulated STIR3 expression in a dose-dependent manner. Upregulated SIRT3 expression and suppressed acetylation of CypD were also observed in H/R-induced H9c2 cells treated with LBP. Indeed, LBP remarkably reversed the inhibition of proliferation and cell apoptosis in H/R-induced H9c2 cells by activating SIRT3/CypD signaling. Blockade of SIRT3 with SIRT3 inhibitor (3-TYP) inhibited the protective effect of LBP on H9c2 cells. LBP markedly alleviated the H/R-induced increase of LDH release, and the decrease of Na+-K+-ATPase activity, Ca2+-ATPase activity, and NO levels. Inhibition of SIRT3 restored the protective effects of LBP. Conclusions: LPB induced deacetylation of CypD by upregulating SIRT3, thereby protecting mitochondrial function and relieving H/R-induced injury in cardiomyocytes.
ABSTRACT
The self-luminous cockpit displays need to be adaptive to a wide range of ambient light levels, which changes from very low illuminance to very high levels. Yet, current studies on evaluation and luminance setting of displays in bright surroundings are still limited. In this study, a three-dimensional visual ergonomic experiment was carried out to investigate how bright a cockpit display should be to meet aircrew operational requirements under different illuminance. A lab study with a within-subjects (N = 12) design was conducted in a simulated cockpit. According to the Weber-Fechner's Law, human observers evaluated five display luminance conditions (101, 101.5, 102, 102.5, 103 cd/m2) under five ambient illuminance conditions (10°, 101, 102, 103, 104 lx). Visual performance, visual fatigue and visual comfort were used as evaluation bases, which were measured by d2 task, subjective fatigue questionnaire and visual perception semantic scales. Nonlinear function fitting was used to calculate the optimal luminance under a certain illuminance. Finally, curvilinear regression was used to analyze the illuminance and its corresponding optimal luminance. Based on Silverstein luminance power function, a luminance adjustment model with the form of power function was obtained. The proposed three-dimensional model fits the experimental data well and is consistent with the existing studies. It can be regarded as a supplement and optimization of the previous model under high ambient illuminance. This study can contribute not only to the pleasing luminance setting of panel displays in aircraft cockpits but also to other self-luminous devices, such as tablet devices, outdoor monitoring equipment and advertising screens.
Subject(s)
Light , Visual Perception , Humans , Data DisplayABSTRACT
Although bright light therapy (BLT) has been widely used in the clinical treatment of depression, the antidepressant effect of BLT is not well understood. Considering the connection between depression and disrupted circadian rhythm, we assumed the model of human circadian phototransduction could be more accurate in evaluating the efficacy of BLT for depression compared to light level and spectrum. A systematic review and meta-analysis were conducted and the CS (circadian stimulus) model was used to quantify the efficacy of lighting in BLT. Articles published up to June 2022 were searched in COCHRANE, EMBASE, MEDLINE, and Web of Science. Randomized clinical trials included articles using high circadian stimulus (H-CS, CS > 0.1) as lighting therapy for people with depressive disorder vs. a control group (CS < 0.1). The treatment effect was estimated by calculating the mean difference (MD) with 95% confidence intervals (CIs). Seven trials involving 258 participants met the inclusion criteria. In this sample size, H-CS lighting was associated with a significant reduction in depressive symptoms (MD = -5.56, 95% CI = -9.22 to -1.90, P = 0.003, I 2 = 64%). According to the meta-analysis, CS can be employed for the clinical evaluation of BLT for patients with depressive disorder and exposure to H-CS lighting significantly reduced depressive symptoms among adults. A range of CS > 0.57 was obtained, during which different lighting parameter combinations (e.g., light levels, spectra, duration, and light distribution) could achieve better treatment for depression. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021253648.
ABSTRACT
Background: Adolescents with immature mind and unstable emotional control are high-risk groups of non-suicidal self-injury (NSSI) behavior. We meta-analyzed the global prevalence of NSSI and prevalence of NSSI characteristics in a non-clinical sample of adolescents between 2010 and 2021. Methods: A systematic search for relevant articles published from January 1, 2010 to June 30, 2021 was performed within the scholarly database search engines of CBM, CNKI, VIP, Wanfang, PubMed, Web of Science, PsycINFO, and Embase. Eligibility criteria were as follows: provided cross-sectional data on the prevalence of NSSI; the subjects were non-clinical sample adolescents; and a clear definition of NSSI was reported. We used the following definiton of NSSI as our standard: the deliberate, self-inflicted destruction of body tissue, such as cutting, burning, and biting, without attempted suicide. The quality evaluation tool for cross-sectional studies recommended by the JBI was used. The global prevalence of NSSI was calculated based on the random-effects model by Comprehensive Meta-analysis version 3.0. Subgroup analyses were performed to compare the prevalence according to sex, living place, smoking or drinking history, and family structure. Results: Sixty-two studies involving 264,638 adolescents were included. The aggregate prevalence of NSSI among a non-clinical sample of adolescents was similar between over a lifetime (22.0%, 95% CI 17.9-26.6) and during a 12-month period (23.2%, 95% CI 20.2-26.5). Repetitive NSSI was more common than episodic NSSI (20.3% vs. 8.3%) but the frequency of mild injury (12.6%) was similar to that of moderate injury (11.6%). Multiple-method NSSI occurred slightly more often compared than one-method NSSI (16.0% vs. 11.1%). The top three types of NSSI in adolescents were banging/hitting (12.0%, 95% CI 8.9-15.9), pinching (10.0%, 95% CI 6.7-14.8), and pulling hair (9.8%, 95% CI 8.3-11.5), and the least common type was swallowing drugs/toxic substances/chemicals (1.0%, 95% CI 0.5-2.2). Subgroup analyses showed that being female, smoking, drinking, having siblings, and belonging to a single-parent family may be linked to higher prevalence of NSSI. Conclusion: This meta-analysis found a high prevalence of NSSI in non-clinical sample of adolescents, but there are some changes in severity, methods, and reasons. Based on the current evidence, adolescents in modern society are more inclined to implement NSSI behavior by a variety of ways, which usually are repetitive, and moderate and severe injuries are gradually increasing. It is also worth noting that adolescents with siblings or in single-parent families are relatively more likely to implement NSSI behavior due to maladjustment to the new family model. Future research needs to continue to elucidate the features and risk factors of NSSI so as to intervene in a targeted way. Limitation: The limitation of this study is that the heterogeneity among the included studies is not low, and it is mainly related to Chinese and English studies. The results of this study should be used with caution. Systematic review registration: [www.crd.york.ac.uk/prospero/], identifier [CRD42022283217].
ABSTRACT
Precise regulation of ion transport through nanoscale pores will profoundly impact diverse fields from separation to energy conversion but is still challenging to achieve in artificial ion channels. Herein, inspired by the exquisite ion selectivity of biological Na+ channels, we have successfully fabricated hierarchically grown metal-organic frameworks (MOFs) on an asymmetrical substrate assisted by atomically thin nanoporous graphene. Efficient separation of monovalent metal ions is realized by encapsulating 18-crown-6 into MOF crystals. The resulting 18-crown-6@ZIF-67/ZIF-8 device, with subnanochannels and specific K+ binding sites, shows an ultrahigh Li+ conductivity of 1.46 × 10-2 S cm-1 and selectivities of 9.56 and 6.43 for Li+/K+ and Na+/K+, respectively. The Li+ conductivity is around 1-2 orders of magnitude higher than reported values for the other MOF materials. It is the first time that MOFs with subnanochannels realize selective transport of Na+ (ionic diameter of 1.9 Å) over K+ (2.6 Å) based on subangstrom differences in their ionic diameter. Our work opens new avenues to develop crown ether@MOF platforms toward efficient ion transistors, fluidic logic devices, and biosensors.
ABSTRACT
Background: Non-suicidal self-injury (NSSI) is being increasingly recognized as a prominent mental health concern, especially among adolescents. In psychiatric clinical samples, its incidence is high and difficult to identify. However, few studies have explored the NSSI behavior of psychiatric hospitalized adolescents. This study aimed to explore the influencing factors of NSSI according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) in adolescents admitted to the psychiatric department. Methods: In this cross-sectional study, by convenient sampling, a total of 505 psychiatric adolescent inpatients aged 10-19 years completed questionnaires to record details of sociodemographic characteristics, the NSSI questionnaire, the Child Psychological Abuse and Neglect Scale (CPANS), the self-report version of the Strengths and Difficulties Questionnaire (self-report SDQ), the Coping Style Scale for Middle School Students (CSSMSS), which were compared between NSSI inpatients and non-NSSI inpatients. This study used the diagnostic criteria for NSSI disorder in DSM-5: adolescent patients who have NSSI behaviors for more than 5 times in the past 1 year are called NSSI. A multiple logistic regression model was built to explore the relationships among general information, CPANS, SDQ, CSSMSS, and NSSI. Risk for NSSI is quantified by odds ratio (OR) with 95% confidence interval (CI). Results: The results showed that 77.82% (n=393) of adolescent inpatients had NSSI, and 80.0% were female (n=404). NSSI adolescent inpatients experienced more family scolding, psychological abuse, and neglect and showed more positive attitudes toward NSSI than non-NSSI adolescent inpatients. However, after controlling for covariables, the difference disappeared. NSSI behavior was significantly associated with female (OR =2.391, 95% CI: 1.396-4.097, P=0.002), younger age (10-14 years old) (OR =1.876, 95% CI: 1.154-3.049, P=0.011), have close friends (OR =0.355, 95% CI: 0.164-0.768, P=0.008), peer discussion about self-injury (OR =1.977, 95% CI: 1.047-3.734, P=0.036), emotional and behavioral difficulties (OR =1.853, 95% CI: 1.054-3.258, P=0.032), problem-oriented coping styles (OR =0.968, 95% CI: 0.945-0.991, P=0.007), emotion-oriented coping styles (OR =1.035, 95% CI: 1.006-41.064, P=0.016). Conclusions: Measures should be taken to prevent and reduce the occurrence of NSSI behaviors among hospitalized adolescents in psychiatric department, which include improving adolescents' attitude towards NSSI, reducing adolescents' gathering behavior in the ward, preventing adolescents from discussing NSSI through social media, improving their coping style when facing difficulties, and reasonably regulating their abnormal emotions and behaviors.
ABSTRACT
Light is an important external factor that affects human circadian rhythms. This study aimed to explore the effects of different dimensions of diurnal light exposure on the physiological circadian phase shift (CPS) of the human body. A strict light exposure experiment with different timing schemes (8:00-12:00, 13:00-17:00, 18:00-22:00), durations (4 h, 8 h) and effective circadian stimulus levels (circadian stimulus: 0.35, 0.55) was performed in an enclosed laboratory. Fourteen participants, including seven males and seven females, with a mean age of 24.29 ± 2.43 (mean ± standard deviation), participated in this experiment and experienced all six lighting schemes. The results showed that both time factor (F 3,40 = 29.079, p < 0.001, the power of the sample size = 0.98) and circadian stimulus levels (T 20 = - 2.415, p = 0.025, the power of sample size = 0.76) significantly affect the CPS. On this basis, a diurnal circadian lighting accumulation (DCLA)-CPS model was proposed in the form of the Boltzmann function, and was validated by experimental data with high correlation (R 2 = 0.9320, RSS = 0.1184), which provides strong support for rationally arranging the light level at different times of the day.
ABSTRACT
Membranes are key components in chemical purification, biological separation, and water desalination. Traditional polymeric membranes are subjected to a ubiquitous trade-off between permeance and selectivity, which significantly hinders the separation performance. Nanoporous atomically thin membranes (NATMs), such as graphene NATMs, have the potential to break this trade-off. Owing to their uniqueness of two-dimensional structure and potential nanopore structure controllability, NATMs are expected to have outstanding selectivity through molecular sieving while achieving ultimate permeance at the same time. However, a drastic selectivity discrepancy exists between the proof-of-concept demonstrations and scalable separation applications in graphene membranes. In this paper, we offer a possible solution to narrow this discrepancy by tuning the pore density and pore size separately with two successive plasma treatments. We demonstrate that by narrowing the pore size distribution, the selectivity of graphene membranes can be greatly increased. Low-energy argon plasma is first applied to nucleate high density of defects in graphene. Controlled oxygen plasma is then utilized to selectively enlarge the defects into nanopores with desired sizes. This method is scalable, and the fabricated 1 cm2 graphene NATMs with sub-nanometer pores can separate KCl and Allura Red with a selectivity of 104 and a permeance of 1.1 × 10-6 m s-1. The pores in NATMs can be further tuned from gas-selective sub-nanometer pores to a few nanometer size. The fabricated NATMs show a selectivity of 35 between CO2 and N2. With longer enlargement time, a selectivity of 21.2 between a lysozyme and bovine serum albumin can also be achieved with roughly four times higher permeance than that of a commercial dialysis membrane. This research offers a solution to realize NATMs of tunable pore size with a narrow pore size distribution for different separation processes from sub-nanometer in gas separation or desalination to a few nanometers in dialysis.
ABSTRACT
Graphene holds great potential for fabricating ultrathin selective membranes possessing high permeability without compromising selectivity and has attracted intensive interest in developing high-performance separation membranes for desalination, natural gas purification, hemodialysis, distillation, and other gas-liquid separation. However, the scalable and cost-effective synthesis of nanoporous graphene membranes, especially designing a method to produce an appropriate porous polymer substrate, remains very challenging. Here, we report a facile route to fabricate decimeter-scale (â¼15 × 10 cm2) nanoporous atomically thin membranes (NATMs) via the direct casting of the porous polymer substrate onto graphene, which was produced by chemical vapor deposition (CVD). After the vapor-induced phase-inversion process under proper experimental conditions (60 °C and 60% humidity), the flexible nanoporous polymer substrate was formed. The resultant skin-free polymer substrate, which had the proper pore size and a uniform spongelike structure, provided enough mechanical support without reducing the permeance of the NATMs. It was demonstrated that after creating nanopores by the O2 plasma treatment, the NATMs were salt-resistant and simultaneously showed 3-5 times higher gas (CO2) permeance than the state-of-the-art commercial polymeric membranes. Therefore, our work provides guidance for the technological developments of graphene-based membranes and bridges the gap between the laboratory-scale "proof-of-concept" and the practical applications of NATMs in the industry.
ABSTRACT
To evaluate the effect of cold application on pain and bruising after the subcutaneous injection of low-molecular-weight heparin, 8 electronic databases were searched for randomized controlled trials and quasiexperimental studies from the inception of the databases to June 2019. Review Manager 5.3 software was used for the heterogeneity test and meta-analysis. A total of 8 studies including 694 participants were analyzed. The cold application group assessed with the Verbal Descriptor Scale pain assessment tool showed significant reductions in pain intensity immediately after injection. Compared to the control group, the cold application group showed a reduction in the occurrence of bruises at 12 hours, 24 hours, and 48 hours after injection. There was no significant difference in the area of bruising in the cold application group at 48 hours after injection, but the area of bruising at 72 hours after injection was significantly reduced. These results show that cold application can reduce the incidence of pain and bruising after subcutaneous injection of low-molecular-weight heparin and reduce the area of bruising 72 hours after injection. Additional studies with larger sample sizes are needed to confirm these findings.
Subject(s)
Contusions/therapy , Cryotherapy/methods , Pain Management/methods , Pain/etiology , Heparin, Low-Molecular-Weight , Humans , Injections, SubcutaneousABSTRACT
OBJECTIVES: This study aims to evaluate the changes of development trends and research hotspots of biomaterials research from 2013 to 2017, which can identify the general information of papers and explore the changes of research content, thus providing perspectives for the development of biomaterials in China and other countries. METHODS: Data of the paper were retrieved from the Web of Science Core Collection, and then analyzed by the bibliometric and CiteSpace visualization analysis. RESULTS: It was found that a total of 3,839 related papers had been published from the year 2013 to 2017. The analysis of the articles showed that the annual quantity and quality of the articles in the biomaterials research have been increasing since 2013, and the Wang L / Chinese Academy of Sciences were the most productive author/institution. Meanwhile, the keywords "in vitro", "scaffold", "nanoparticle" , "mechanical property", and "biocompatibility" have the relatively higher frequency, and the keywords "apatite", "deposition", and "surface modification" have the strongest burst citation. CONCLUSIONS: After statistics and analysis, we found that biomaterials is a promising research field. The study may be helpful in understanding research trends in this field.
ABSTRACT
The article collected 250 renew registration of domestic Class â ¡ passive medical devices from Jan. 2016 to Aug. 2017 in Shanghai. It summarized the common problems listed in the correction notifications of the technical evaluation, and then provides some relevant countermeasures or suggestions. So that we can further speed up the evaluation and approval of medical devices.
Subject(s)
Device Approval , Equipment and Supplies , China , RegistriesABSTRACT
Sutures are a vital part for surgical operation, and suture-associated surgical site infections are an important issue of postoperative care. Antibacterial sutures have been proved to reduce challenging complications caused by bacterial infections. In recent decades, triclosan-free sutures have been on their way to commercialization. Alternative antibacterial substances are becoming relevant to processing surgical suture materials. Most of the antibacterial substances are loaded directly on sutures by dipping or coating methods. The aim of this study was to optimize novel antibacterial braided silk sutures based on levofloxacin hydrochloride and poly(ε-caprolactone) by two different processing sequences, to achieve suture materials with slow-release antibacterial efficacy and ideal physical and handling properties. Silk strands were processed into sutures on a circular braiding machine, and antibacterial treatment was introduced alternatively before or after braiding by two-dipping-two-rolling method (M1 group and M2 group). The antibacterial activity and durability against Staphylococcus aureus and Escherichia coli were tested. Drug release profiles were measured in phosphate buffer with different pH values, and release kinetics model was built to analyze the sustained drug release mechanism between the interface of biomaterials and the in vitro aqueous environment. Knot-pull tensile strength, thread-to-thread friction, and bending stiffness were determined to evaluate physical and handling properties of sutures. All coated sutures showed continuous antibacterial efficacy and slow drug release features for more than 5 days. Besides, treated sutures fulfilled U.S. Pharmacopoeia required knot-pull tensile strength. The thread-to-thread friction and bending stiffness for the M1 group changed slightly when compared with those of uncoated ones. However, physical and handling characteristics of the M2 group tend to approach those of monofilament ones. The novel suture showed acceptable in vitro cytotoxicity according to ISO 10993-5. Generally speaking, all coated sutures show potential in acting as antibacterial suture materials, and M1 group is proved to have a higher prospect for clinical applications.
Subject(s)
Anti-Bacterial Agents/chemistry , Silk/chemistry , Animals , Anti-Bacterial Agents/pharmacology , Cell Line , Cell Survival/drug effects , Disk Diffusion Antimicrobial Tests , Drug Carriers/chemistry , Drug Carriers/toxicity , Drug Liberation , Escherichia coli/drug effects , Levofloxacin/chemistry , Levofloxacin/pharmacology , Mice , Polyesters/chemistry , Staphylococcus aureus/drug effects , Sutures , Tensile StrengthABSTRACT
Surgical braided silk sutures have been widely used because these materials exhibit good handling characteristics, ease of use, and ideal knot security. However, surgical silk sutures likely cause surgical site infections because these sutures are composed of natural protein materials with a braided structure. As such, antibacterial silk sutures for clinical wound closure should be developed. Braided silk suture could be treated and modified with antibacterial agent, provided that excellent physical and handling characteristics of this material should maximize maintained. This study aimed to quantitatively investigate the effect of antibacterial treatment with different parameters on physical and handling characteristics of novel antibacterial braided silk sutures. Physical and handling characteristics, including appearance, knot-pull tensile strength, pullout friction resistance, tissue drag friction resistance, and bending stiffness, were evaluated. After physical and handling tests were conducted, images showed morphological characteristics were obtained and evaluated to investigate the relationship between antibacterial treatment and physical and handling properties. Results showed that suture diameter increased and reached the nearest thick size specification; knot-pull tensile strength decreased but remained higher than the standard value by at least 40.73%. Fracture asynchronism during knot-pull tensile strength test suggested that the fineness ratio of shell and core strands may enhance knot-pull tensile strength. Static and dynamic frictions of suture-to-suture friction behavior were slightly affected by antibacterial treatment, and changed to less than 16.07% and 32.77%, respectively. Suture-to-tissue friction and bending stiffness increased by approximately 50%; the bending stiffness of the proposed suture remained efficient compared with that of synthetic sutures. Therefore, good physical and handling characteristics can be maintained by selecting appropriate coating parameters.
Subject(s)
Anti-Bacterial Agents , Friction , Silk , Sutures , Tensile Strength , Materials TestingABSTRACT
Hyperhomocysteinemia is an independent risk factor for cardiovascular diseases. The enhanced nitrative stress plays an important role in homocysteine-induced endothelial dysfunction. Previous studies have showed that phytoestrogen α -zearalanol alleviated endothelial injury in ovariectomized hyperhomocysteinemic rats; however, the underlying mechanism remains to be clarified. This study was to investigate the effects of α -zearalanol on homocysteine-induced endothelial apoptosis in vitro and explore the possible role of nitrative stress in these effects. Results showed that homocysteine (500 µ mol/L, 24 h) induced the apoptosis of human umbilical vein endothelial cells (HUVECs) obviously, and this effect was significantly attenuated by pretreatment with α -zearalanol (10(-8)~10(-6) mol/L). Moreover, α -zearalanol downregulated proapoptotic protein Bax, upregulated antiapoptotic proteins Bcl-2 and Bcl-XL, and decreased the expression and activity of caspase-9. These findings demonstrated that α -zearalanol could effectively alleviate homocysteine-induced endothelial apoptosis, and this antiapoptosis effect might be related to the inhibition of the intrinsic pathway. Western blot indicated an enhanced 3-nitrotyrosine expression in HUVECs when challenged with homocysteine, which was attenuated by pretreatment with α -zearalanol. This result implied that inhibition of nitrative stress might play a role in the protective effect of α -zearalanol on endothelial cells. Such discovery may shed a novel light on the antiatherogenic activities of α -zearalanol in hyperhomocysteinemia.