Inhalable Polymeric Microparticles for Phage and Photothermal Synergistic Therapy of Methicillin-Resistant Staphylococcus aureus Pneumonia.

Acute methicillin-resistant Staphylococcus aureus (MRSA) pneumonia is a common and serious lung infection with high morbidity and mortality rates. Due to the increasing antibiotic resistance, toxicity, and pathogenicity of MRSA, there is an urgent need to explore effective antibacterial strategies. In this study, we developed a dry powder inhalable formulation which is composed of porous microspheres prepared from poly(lactic-co-glycolic acid) (PLGA), internally loaded with indocyanine green (ICG)-modified, heat-resistant phages that we screened for their high efficacy against MRSA. This formulation can deliver therapeutic doses of ICG-modified active phages to the deep lung tissue infection sites, avoiding rapid clearance by alveolar macrophages. Combined with the synergistic treatment of phage therapy and photothermal therapy, the formulation demonstrates potent bactericidal effects in acute MRSA pneumonia. With its long-term stability at room temperature and inhalable characteristics, this formulation has the potential to be a promising drug for the clinical treatment of MRSA pneumonia.

A comparison of accuracy among different approaches of static-guided implant placement in patients treated with mandibular reconstruction: A retrospective study.

OBJECTIVE: This study aimed to evaluate the differences in the accuracy of immediate intraoral, immediate extraoral, and delayed dental implant placement with surgical guides (static computer-aided implant surgery) in patients treated with mandibular reconstruction. METHODS: This was a retrospective study. The patients were divided into three groups: immediate intraoral placement (IIO), immediate extraoral placement (IEO), and delayed placement (DEL). Four variables were used to compare the planned and actual implant positions: angular deviation, three-dimensional (3D) deviation at the entry point of the implant, 3D deviation at the apical point of the implant, and depth deviation. RESULTS: The angular deviation was significantly higher in the IIO group than in the IEO (p < .05) and DEL (p < .05) groups. The 3D deviation at the entry point was significantly higher in the IIO group than in the IEO (p < .05) and DEL (p < .01) groups. The 3D deviation at the apical point was significantly higher in the IIO group than in the IEO (p < .01) and DEL (p < .01) groups. The depth deviation was significantly higher in the IIO group than in the IEO (p < .05) and DEL (p < .05) groups. There was no statistical difference between the IEO and DEL group in angular and 3D deviation. CONCLUSION: With surgical guides, among the different approaches for implant placement, delayed implant placement remains the most accurate approach for patients treated with mandibular reconstruction.

Allylamine coating on zirconia dental implant surface promotes osteogenic differentiation in vitro and accelerates osseointegration in vivo.

OBJECTIVES: The glow discharge plasma (GDP) procedure has proven efficacy in grafting allylamine onto zirconia dental implant surfaces to enhance osseointegration. This study explored the enhancement of zirconia dental implant properties using GDP at different energy settings (25, 50, 75, 100, and 200 W) both in vitro and in vivo. MATERIALS AND METHODS: In vitro analyses included scanning electron microscopy, wettability assessment, energy-dispersive X-ray spectroscopy, and more. In vivo experiments involved implanting zirconia dental implants into rabbit femurs and later evaluation through impact stability test, micro-CT, and histomorphometric measurements. RESULTS: The results demonstrated that 25 and 50 W GDP allylamine grafting positively impacted MG-63 cell proliferation and increased alkaline phosphatase activity. Gene expression analysis revealed upregulation of OCN, OPG, and COL-I. Both 25 and 50 W GDP allylamine grafting significantly improved zirconia's surface properties (p < .05, p < .01, p < .001). However, only 25 W allylamine grafting with optimal energy settings promoted in vivo osseointegration and new bone formation while preventing bone level loss around the dental implant (p < .05, p < .01, p < .001). CONCLUSIONS: This study presents a promising method for enhancing Zr dental implant surface's bioactivity.

Dynamic biomechanical changes of clear aligners during extraction space closure: Finite element analysis.

INTRODUCTION: Clear aligners (CAs) have recently become popular and widely used orthodontic appliances. Research on CA biomechanics has become a focal point in orthodontics to improve the efficiency of CA treatment and address challenging issues, such as extraction. The biomechanical characteristics of CAs in space closure have been reported. However, previous studies have mainly focused on static biomechanical analysis that cannot demonstrate the dynamic biomechanical changes in CAs during space-closing. Given that these biomechanical changes can be significant and have considerable clinical value, this study aimed to investigate these characteristics. METHODS: Sequential extraction space-closing models were derived from included patient data and refined using modeling and CA design software. A finite element analysis was performed to obtain biomechanical raw data. This study introduced a dual coordinate system and space geometry analysis to demonstrate the biomechanical properties accurately. RESULTS: As space closure progressed, the instantaneous tooth displacements increased, indicating an enhanced space closure force because of the increased strain in the CA extraction area. Meanwhile, the central axis of rotation of the anterior teeth continuously moved toward the labial-apical direction, showing a gradually enhanced vertical and torque control effect. CONCLUSIONS: During space closure, CAs undergo specific biomechanical changes, including increased contraction and control forces on both sides of the gap. These biomechanical effects are beneficial to alleviate the roller coaster effect gradually. Meanwhile, more reasonable staging design strategies can be proposed on the basis of this biomechanical mechanism.

Photoswitchable and Solvent-Controlled Directional Actuators: Supramolecular Assembly and Crosslinked Polymers.

Untethered small actuators have drawn tremendous interest owing to their reversibility, flexibility, and widespread applications in various fields. For polymer actuators, however, it is still challenging to achieve programmable structural changes under different stimuli caused by the intractability and single-stimulus responses of most polymer materials. Herein, multi-stimuli-responsive polymer actuators that can respond to light and solvent via structural changes are developed. The actuators are based on bilayer films of polydimethylsiloxane (PDMS) and azobenzene chromophore (AAZO)-crosslinked poly(diallyldimethylammonium chloride) (PDAC). Upon UV light irradiation, the AAZO undergoes trans-cis-trans photoisomerization, causing the bending of the bilayer films. When the UV light is off, a shape recovery toward an opposite direction occurs spontaneously. The reversible deformation can be repeated at least 20 cycles. Upon solvent vapor annealing, one of the bilayer films can be selectively swollen, causing the bending of the bilayer films with the directions controlled by the solvent vapors. The effects of different parameters, such as the weight ratios of AAZO and film thicknesses, on the bending angles and curvatures of the polymer films are also analyzed. The results demonstrate that multi-stimuli-responsive actuators with fast responses and high reproducibility can be fulfilled.

Benzimidazolone-Dioxazine Pigments-Based Conjugated Polymers for Organic Field-Effect Transistor.

Molecules based on benzimidazolone-dioxazine are known as blue/violet pigments and have been commercialized for decades. However, unfavorable solubility limits the application of these structures as building blocks of conjugated polymers despite their low band gaps. Herein, a series of donor-acceptor conjugated polymers containing soluble benzimidazolone-dioxazine structures as the acceptors and oligothiophene as donors are synthesized and investigated. With increasing numbers of thiophene rings, the steric hindrance diminishes and high molecular weight polymers can be achieved, leading to an improved performance in organic field effect transistor devices. The hole mobility of polymers with three to six thiophene units is in the order of 10-1 cm2 V-1 s -1 . Among all the polymers, polymer P3 with three thiophene units between benzimidazolone-dioxazine structures shows the best hole mobility of 0.4 cm2 V-1 s -1 . Grazing-incidence wide-angle X-ray scattering results reveal that the high mobility of organic field-effect transistors (OFETs) can be accredited by matched donor-acceptor packing in the solid thin films.

Iliac crest towards alveolar processes or mandibular inferior margin in mandibular reconstruction with a vascularized iliac bone flap: which is better?

OBJECTIVE: The study aims to compare differences among iliac bone flaps with different iliac crest orientations for the repair of mandibular defects with an aim to analyze their advantages, disadvantages, and effects. MATERIAL AND METHODS: Clinical data and computed tomography scans of all patients who underwent iliac bone flap repair of the mandible in Peking University School and Hospital of Stomatology from January 2016 to April 2021 were collected. Patients were divided into the iliac crest towards alveolar process (Group A) and the iliac crest towards mandibular inferior margin (Group B). Software was used to measure corresponding indicators. The results obtained for the groups were statistically analyzed. RESULTS: The study included 78 patients (25 and 53 in groups A and B, respectively). The symmetry of the LC-type defect was better in group A (p < 0.05). The all-bone width of the alveolar process side in group A was greater than 6 mm; in 15 cases of group B, the width was less than 6 mm (p < 0.05). The intermaxillary distance of two sites were higher in group B (p < 0.05). The bone cortical thickness was significantly thicker in group A (p < 0.05). CONCLUSION: One year after the mandibular body defect was reconstructed with a vascularized iliac bone flap, the iliac crest towards alveolar process group showed better bone symmetry, width, intermaxillary distance, and cortical thickness to meet the planting requirements. CLINICAL RELEVANCE: The use of an iliac crest towards alveolar process may be a better approach for mandible reconstruction.

Clinical Characterization of Oral and Maxillofacial Tumors and Tumor-Like Lesions in Children and Adolescents.

PURPOSE: To investigate the clinical characteristics of oral and maxillofacial tumors in children and adolescents. METHODS: This is a retrospective study of patients who had oral and maxillofacial tumors under the age of 18 years and were treated at the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from January 1990 to July 2021 (31 y). Their general conditions, pathological diagnosis, gender, age, and anatomical location were counted to analyze their morbidity and composition characteristics. RESULTS: This study contained 5405 cases, including 2903 male patients and 2502 female patients, with a median age of 9 years. Peak incidence was observed in the 14 to 18 years age group. The mandible (22.15%), maxilla (11.75%), and tongue (9.25%) were the most common sites of incidence. Malignant and intermediate type tumors accounted for 13.04%, benign tumors and tumor-like lesions for 55.67%, most often occurs in the maxillofacial bone, of which fibro-osseous lesions constitute an important part. Cysts accounted for 31.29%. Among the tumors occurring in the jaws, the most common malignant type was sarcoma, and ameloblastoma was the most common benign tumor. Malignant jaw tumors were mostly treated by resection, 10.64% by fibular flap reconstruction. While benign jaw tumors and tumor-like lesions were mostly treated by resection or curettage. CONCLUSIONS: The distribution of anatomical location and pathological types of oral and maxillofacial tumors in children has certain characteristics, so that the selection of their treatment options is different from that of adults due to the consideration of the growth and developmental characteristics of children.

Vascularized Free Fibular Flap in Oral and Maxillofacial Reconstruction: A 20-year Experience at a Single Institution Using 2640 Flaps.

BACKGROUND: This retrospective study reviewed all patients who underwent oral and maxillofacial reconstruction with fibular flaps in the last 2 decades at a single hospital. MATERIALS AND METHODS: We reviewed all patients with fibular flaps from 1999 to 2018. The following data were collected: sex; age; reconstruction region; diagnosis; the number of days spent in the hospital after surgery; time spent using a tourniquet for harvesting a fibula flap; vessels at the recipient site; the prevalence of unplanned reoperations; the prevalence of flap failure; history of preoperative radiotherapy; virtual surgical planning; segments of the fibula. RESULTS: In total, 2640 patients were included. The mean age was 45.5 years. The most prevalent region of reconstruction was the mandible (n=2347, 88.9%). The most common diagnosis was squamous cell carcinoma (n=1057, 40.0%). The mean number of days spent in the hospital after surgery decreased year-by-year from 18.3 days to 10.4 days. The first choice of recipient artery was the facial artery (n=1643, 62.2%) and that of the recipient vein was the external jugular vein (n=1196, 45.3%). The prevalence of surgical success was 97.6%. Prevalence of unplanned reoperations was 7.5%. CONCLUSIONS: The fibular flap was a good choice for oral and maxillofacial bony reconstruction in most cases.

An assessment of oral cancer knowledge, attitudes, and practices among undergraduate students in Malaysian dental schools.

BACKGROUND: Oral cancer is a significant public health concern worldwide. Early detection and prevention are crucial in reducing the morbidity and mortality rates associated with this disease. As future dental professionals, dental undergraduates play a vital role in promoting oral health and identifying potential oral cancer cases. METHODS: This study aimed to evaluate the level of oral cancer awareness, knowledge, attitudes, and practices among dental undergraduates in Malaysia. A total of 595 students from years 3, 4, and 5 in both public and private universities participated. RESULTS: The results showed that a higher percentage of dental undergraduates from private universities were aware of oral cancer and had satisfactory knowledge compared to those from public universities (p < 0.05). Moreover, 59.4% of respondents felt less confident in diagnosing oral cancer during routine dental practice, and 96.1% agreed on the need to increase public awareness of oral health. Interestingly, students from private universities exhibited higher levels of awareness and knowledge regarding oral cancer than those from public universities. CONCLUSIONS: To enhance oral cancer detection and prevention, it is essential to reinforce the current curriculum and provide training to improve diagnostic skills for every dental undergraduate. This will ensure that they are well-equipped with the necessary knowledge and competence to detect and prevent oral cancer effectively.

Factorial structure and measurement invariance of the Chinese version of the Oral Health Impact Profile-14 among clinical populations and non-clinical populations: an evidence for public oral investigations.

OBJECTIVE: Oral health-related quality of life (OHRQoL) is a multidimensional concept that is commonly used to examine the impact of oral health status on quality of life. The purpose of this study was to examine the optimal factor model of the Chinese version of the Oral Health Impact Profile (OHIP-14) questionnaire in clinical populations, measurement invariance across clinical status and gender cohorts. This would ensure equal validity of the Chinese version of OHIP-14 in different populations and further support public oral investigations. METHODS: The Chinese version of OHIP-14 was used to investigate 490 dental patients and 919 college students. Confirmatory factor analysis (CFA), item analysis and reliability, measurement invariance, and the t-test were used for data analyses. RESULTS: We found that the 7-factor structure had the best-fit index in the sample (CFI = 0.970, TLI = 0.952; SRMR = 0.029, RMSEA = 0.052(0.040,0.063)). The reliability of the scales was satisfactory (Cronbach's α = 0.942). The error variance invariance fitted the data adequately in measurement invariance, indicating that measurement invariance is acceptable both across the clinical and non-clinical populations (∆CFI=-0.017, ∆RMSEA = 0.010) and across genders in the clinical population (∆CFI = 0.000, ∆RMSEA=-0.003). T-test for scores showed that the clinical populations scored significantly higher than the non-clinical populations, as did the overall score (t = 7.046, p < 0.001, d = 0.396), in terms of functional limitation (t = 2.178, p = 0.030, d = 0.125), physical pain (t = 7.880, p < 0.001,d = 0.436), psychological discomfort (t = 8.993, p < 0.001, d = 0.514), physical disability (t = 6.343, p < 0.001, d = 0.358), psychological disability (t = 5.592, p < 0.001, d = 0.315), social disability (t = 5.301, p < 0.001,d = 0.304), social handicap (t = 4.452, p < 0.001, d = 0.253), and that in the non-clinical populations, females scored significantly higher than males, as did in terms of physical pain (t = 3.055, p = 0.002, d = 0.280), psychological discomfort (t = 2.478, p = 0.014, d = 0.222), and psychological disability (t = 2.067, p = 0.039, d = 0.188). CONCLUSION: This study found that the Chinese version of OHIP-14 has measurement invariance between the clinical and non-clinical populations and across genders in the clinical populations, and can be widely used in OHRQoL assessment for public oral investigations.

Mandibular Reconstruction Using Iliac Flap Based on Occlusion-Driven Workflow Transferred by Digital Surgical Guides.

PURPOSE: The current standard for mandibular reconstruction is a contour-based approach using a fibular flap offering good cosmetic results but challenging to reconstruct using dental implants. An iliac flap is more amenable to implant placement and better suited for occlusion-driven reconstruction. We aimed to describe an occlusion-driven workflow that involves the use of digital surgical guides to perform mandibular reconstruction using an iliac flap; we also aimed to compare our results to those we achieved with conventional contour-based reconstruction. METHODS: This was a retrospective cohort study. All patients who underwent mandibular reconstruction with an iliac flap at our university hospital between September 2017 and December 2019 were considered eligible for the study. The inclusion criteria included mandibular defects after tumor ablation and stable preoperative occlusal relationship. The exclusion criteria were as follows: defects involving the condyle and ramus, temporomandibular joint disease, and obvious preoperative nontumor-related facial asymmetry. To evaluate surgical outcomes, patients were assigned to 2 groups based on the implemented surgical workflow: the occlusion-driven and traditional contour-driven groups. The intermaxillary distance, intermaxillary angle, surface deviation, and implantation rates were compared between the 2 groups. The operating time, length, and number of iliac bone segments were recorded. Intergroup differences were investigated using an independent samples t test and Fisher exact test. RESULTS: Overall, 24 patients were included (13 in the occlusion-driven group and 11 in the contour-driven group). Implantation rate was higher in the occlusion-driven group (61.5%) compared with the contour-driven group (18.2%; P = .047). The average acceptable intermaxillary distance was greater in the occlusion-driven group (92.3 ± 27.7%) than in the contour-driven group (47.0 ± 47.6%; P = .01). The average intermaxillary angle was 88.2 ± 8.4° in the occlusion-driven group and 76.4 ± 10.3° in the contour-driven group (P < .01). CONCLUSIONS: Digital surgical guides can precisely transfer virtual surgical planning to real-world mandibular surgery. An occlusion-driven workflow might provide a better intermaxillary jaw relationship than traditional contour-driven surgical procedures, resulting in improved mastication.

Regulation of stem cell fate using nanostructure-mediated physical signals.

One of the major issues in tissue engineering is regulation of stem cell differentiation toward specific lineages. Unlike biological and chemical signals, physical signals with adjustable properties can be applied to stem cells in a timely and localized manner, thus making them a hot topic for research in the fields of biomaterials, tissue engineering, and cell biology. According to the signals sensed by cells, physical signals used for regulating stem cell fate can be classified into six categories: mechanical, light, thermal, electrical, acoustic, and magnetic. In most cases, external macroscopic physical fields cannot be used to modulate stem cell fate, as only the localized physical signals accepted by the surface receptors can regulate stem cell differentiation via nanoscale fibrin polysaccharide fibers. However, surface receptors related to certain kinds of physical signals are still unknown. Recently, significant progress has been made in the development of functional materials for energy conversion. Consequently, localized physical fields can be produced by absorbing energy from an external physical field and subsequently releasing another type of localized energy through functional nanostructures. Based on the above concepts, we propose a methodology that can be utilized for stem cell engineering and for the regulation of stem cell fate via nanostructure-mediated physical signals. In this review, the combined effect of various approaches and mechanisms of physical signals provides a perspective on stem cell fate promotion by nanostructure-mediated physical signals. We expect that this review will aid the development of remote-controlled and wireless platforms to physically guide stem cell differentiation both in vitro and in vivo, using optimized stimulation parameters and mechanistic investigations while driving the progress of research in the fields of materials science, cell biology, and clinical research.

The Treatment Efficiency and Microbiota Analysis of Sapindus mukorossi Seed Oil on the Ligature-Induced Periodontitis Rat Model.

Periodontitis is a common oral disease mainly caused by bacterial infection and inflammation of the gingiva. In the prevention or treatment of periodontitis, anti-bacterial agents are used to inhibit pathogen growth, despite increasing levels of bacterial resistance. Sapindus mukorossi Gaertn (SM) seed oil has proven anti-bacterial and anti-inflammation properties. However, the possibility of using this plant to prevent or treat periodontitis has not been reported previously. The aim of this study was to evaluate the effects of SM oil on experimental periodontitis in rats by using micro-CT and microbiota analysis. The distance between cementoenamel junction (CEJ) and alveolar bone crest (ABC) on the sagittal micro-CT slide showed that total bone loss (TBL) was significantly lower in CEJ-ABC distances between SM oil and SM oil-free groups on Day 14. Histology data also showed less alveolar bone resorption, a result consistent result with micro-CT imaging. The microbiota analyzed at phylum and class levels were compared between the SM oil and SM oil-free groups on Day 7 and Day 14. At the phylum level, Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria were the dominant bacterium. Firmicutes in box plot analysis was significantly less in the SM oil group than in the SM oil-free group on Day 7. At the class level, Bacteroidia, Gammaproteobacteria, Bacilli, Clostridia, and Erysipelotrichia were the dominant bacteria. The bacteria composition proportion of Bacilli, Clostridiay, and Erysipelotrichia could be seen in the SM oil group significantly less than in t SM oil-free group on Day 7. Overall, the present results show that topical application of SM oil can reduce bone resorption and change bacteria composition in the ligature-induced periodontitis model. According to these results, it is reasonable to suggest SM oil as a potential material for preventing oral disease.

Preparation of Calcium Phosphate Compounds on Zirconia Surfaces for Dental Implant Applications.

Titanium is widely used in medical implants despite the release of heavy metal ions over long-term use. Zirconia is very close to the color of teeth; however, its biological inertness hinders bonding with bone tissue. Alkaline treatment and coatings of calcium phosphate can be used to enhance bone regeneration adjacent to dental implants. This study examined the effects of alkaline treatment, calcium phosphate coatings, and sintering, on the physical properties of implant material. Our analysis confirmed that the calcium phosphate species were octacalcium phosphate (OCP). The sintering of calcium phosphate was shown to create B-type HAP, which is highly conducive toward the differentiation of mesenchymal stem cells (MSCs) into osteoblasts for the facilitation of bone integration. Conclusions: This study demonstrated the room-temperature fabrication of dental implants with superhydrophilic surfaces to enhance biocompatibility.

Effect of Molar Substitution on the Properties of γ-Hydroxypropyl Starch.

A new type of hydroxyalkyl starch, γ-hydroxypropyl starch (γ-HPS), was prepared by etherification of alkali-activated starch with 3-chloropropanol. The reaction efficiency, morphological change, thermodynamic and apparent viscosity properties, and other physicochemical characteristics were described. The molar substitution (MS) of modified whole starch was determined to be 0.008, 0.017, 0.053, 0.106, and 0.178, with a ratio of 5%, 15%, 25%, 35%, and 45% 3-chloropropanol to starch (v/w), respectively. Compared to native starch, the granular size and shape and the X-ray diffraction pattern of γ-HPS are not very different. For low-substituted γ-HPS, the implications may be less evident. Thermal stability measurements by means of thermogravimetric analyses and differential scanning calorimetry (TGA-DSC) proved that thermal stability was reduced and water retaining capacity was increased after hydroxypropylation. Furthermore, the findings also showed that the solubility, light transmittance, and retrogradation of γ-HPS pastes could be improved by etherification. The greater the MS of the γ-HPS, the more its freeze-thaw stability and acid resistivity increased. In this study, we provide relevant information for the application of γ-HPS in food and non-food industries.

Inorganic-Organic Hybrid Membrane Based on Pillararene-Intercalated MXene Nanosheets for Efficient Water Purification.

Discharge of antibiotic-containing wastewater causes environmental pollution and threatens biological and human health. An efficient treatment method for this wastewater is urgently required. We prepared inorganic-organic hybrid MXene-pillararene nanosheets with a large lateral size (5-8 µm). The hybrid nanosheets were stacked on supports via vacuum-assisted filtration to prepare membranes with regular parallel slits and an interlayer spacing of 1.36 nm, which were used to purify antibiotic-containing water. Permeance through the membrane increased 100-fold compared with most polymeric and other two-dimensional nanofiltration membranes with similar rejection. This high permeance and rejection was attributed to the large lateral size of the nanosheets, regular interlayer spacing, and electrostatic interaction between the membrane and antibiotics. These membranes will broaden the applications of lamellar materials for the separation of high-value-added drugs in academia and industry.

Photoswitchable Composite Polymer Electrolytes Using Spiropyran-Immobilized Nanoporous Templates.

Composite polymer electrolytes (CPEs) with smart, stimuli-responsive characteristics have gained considerable attention owing to their noninvasive manipulation and applications in future technologies. To address this potential, in this work, we demonstrate photoresponsive composite polymer electrolytes, consisting of gel polymer electrolyte (GPE) and spiropyran-immobilized nanoporous anodic aluminum oxide (SP-AAO) templates. Under UV irradiation, the close SP form isomerizes to the open merocyanine (MC) form, creating extremely polarized AAO surfaces; whereas, under visible light irradiation, the MC form reverts to the SP form, creating neutral surface conditions. The electrostatic interactions between ions and AAO surfaces are investigated by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. Moreover, the behavior of ionic conductivity of the GPE@SP-AAO is found to be consistent with the kinetics of isomerization tracked by UV-Vis spectroscopy. This work provides a promising platform for developing next-generation photoelectronic smart devices.

Assessment bioaccumulation factor (BAF) of methyl siloxanes in crucian carp (Carassius auratus) around a siloxane production factory.

Methyl siloxanes are identified as emerging persistent toxic compounds and the ecological environment risks of these compounds have been caused of great concern worldwide. In this study, the concentrations of methyl siloxanes were reported in dissolved water and crucian carp around a methyl siloxane production factory located in Liaoning Province, Northeast China. D4, D5, D6, D7, L4, L5 and L6 were detectable both in dissolved water and crucian carp. The total concentrations of 7 methyl siloxanes (Σ7MS) were 14 ± 6.3 ng/L in dissolved water and 43 ± 22 ng/g ww in crucian carp, respectively. D5 has the highest concentration both in dissolved water (5.5 ± 3.5 ng/L) and crucian carp (17 ± 11 ng/g ww). Based on the monitoring values, bioaccumulation factor (BAF) of these compounds were calculated. Significant bioaccumulation potential was observed for D4 (BAF = 5900 ± 3500 L/kg) based on the bioaccumulation criteria suggested by USEPA and EU (BAF > 5000 L/kg). To our understanding, this is the first report of BAF values of methyl siloxane in field study, which will provide important support for further assessment of bioaccumulation of these compounds.

In-Situ Synchrotron SAXS and WAXS Investigation on the Deformation of Single and Coaxial Electrospun P(VDF-TrFE)-Based Nanofibers.

Coaxial core/shell electrospun nanofibers consisting of ferroelectric P(VDF-TrFE) and relaxor ferroelectric P(VDF-TrFE-CTFE) are tailor-made with hierarchical structures to modulate their mechanical properties with respect to their constituents. Compared with two single and the other coaxial membranes prepared in the research, the core/shell-TrFE/CTFE membrane shows a more prominent mechanical anisotropy between revolving direction (RD) and cross direction (CD) associated with improved resistance to tensile stress for the crystallite phase stability and good strength-ductility balance. This is due to the better degree of core/shell-TrFE-CTFE nanofiber alignment and the crystalline/amorphous ratio. The coupling between terpolymer P(VDF-TrFE-CTFE) and copolymer P(VDF-TrFE) is responsible for phase stabilization, comparing the core/shell-TrFE/CTFE with the pristine terpolymer. Moreover, an impressive collective deformation mechanism of a two-length scale in the core/shell composite structure is found. We apply in-situ synchrotron X-ray to resolve the two-length scale simultaneously by using the small-angle X-ray scattering to characterize the nanofibers and the wide-angle X-ray diffraction to identify the phase transformations. Our findings may serve as guidelines for the fabrication of the electrospun nanofibers used as membranes-based electroactive polymers.