Quantitation of levetiracetam concentrations in plasma and saliva samples by ultra-performance liquid chromatography-tandem mass spectrometry: Application to therapeutic drug monitoring for pregnant women with epilepsy.

Although levetiracetam (LEV) has favorable linear pharmacokinetic properties, therapeutic drug monitoring (TDM) is necessary for pregnant women with epilepsy. This study aims to build a simple, reliable, and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determining LEV concentrations in plasma and saliva samples, to support the routine TDM of LEV in Chinese pregnant women with epilepsy. The stable isotope-labeled LEV-d6 was used as the internal standard. The extracted samples were analyzed using a UPLC-MS/MS system with positive electrospray ionization. Mobile phase A was water containing 5 mM ammonium acetate and 0.1% formic acid, and phase B was 1:1 methanol-acetonitrile with 0.1% formic acid. The method was validated and utilized to determine LEV concentrations in non-pregnant and pregnant patients with epilepsy. The developed method was validated in both plasma and saliva samples over a concentration range of 0.1-50 µg/mL. The intra- and inter-batch accuracy for LEV ranged from -7.0% to 2.9%, with precisions between 2.7% and 9.3%. In pregnant patients, the mean dose-standardized LEV trough plasma concentrations were significantly lower than those in non-pregnant patients (4.73 ± 2.99 vs. 7.74 ± 3.59 ng/mL per mg/day; P < 0.0001). It is recommended that the TDM of LEV should be routinely performed during the different stages of pregnancy.

Vitamin intake and periodontal disease: a meta-analysis of observational studies.

OBJECTIVE: A meta-analysis was performed to assess the epidemiological correlation between dietary intake of various types of vitamin intake and the risk of periodontal disease. METHODS: A comprehensive computerized search was conducted in eight databases, namely PubMed, Web of Science, Embase, Cochrane Library, China Biology Medicine Disc, CNKI, VIP, and WanFang Database, and a random effect model was applied to combine pooled odds ratio (ORs) with corresponding 95% confidence intervals (CIs) of the included studies, and the sensitivity analysis was performed to explore the impact of a single study on the comprehensive results. RESULTS: We finally included 45 effect groups from 23 observational studies, with a total number of study participants of 74,488. The results showed that higher levels of vitamin A (OR: 0.788, 95% CI: 0.640-0.971), vitamin B complex (OR: 0.884, 95% CI: 0.824-0.948), vitamin C (OR: 0.875, 95% CI: 0.775-0.988), vitamin D (OR: 0.964, 95% CI: 0.948-0.981), and vitamin E (OR: 0.868, 95% CI: 0.776-0.971) intake all were negatively correlated with periodontal disease. After removing each study, leave-one-out sensitivity analysis indicated no significant change in the overall results of any of the five meta-analyses. CONCLUSIONS: The results from this meta-analysis demonstrated a negative association between high-dose vitamin A, vitamin B complex, vitamin C, vitamin D, and vitamin E consumption and the likelihood of developing periodontal disease, revealing the significant role of vitamins in preventing periodontal disease.

Reconstruction of the Defect at Temporal Hairline by a Scalp Keystone Island Flap: Clinical Experience on 14 Cases.

BACKGROUND: The reconstructions of defects at the temporal hairline always require more complicated designs and higher surgical skills to acquire better aesthetic results. By taking advantage of the unique anatomy of the temporal region, the authors designed a scalp keystone island flap pedicled by superficial temporal fascia to repair defects on the temporal hairline. METHODS: The authors retrospectively analyzed the clinical data of 14 patients who had lesions adjacent to the temporal hairline between April 2018 and June 2020. Patients were diagnosed with basal cell carcinoma, squamous-cell carcinoma, or seborrheic keratosis. These lesions were resected and reconstructed by scalp keystone island flaps. The defects ranged from 2.0 cm × 1.5 cm to 3.0 cm × 3.5 cm. RESULTS: All patients were satisfied with postoperative morphology and reported no recurrence at the 6 to 24 months follow-up. Flaps in two patients were partially necrosed but eventually healed by dressing changes. The rest had the first intention of healing. CONCLUSIONS: The scalp keystone island flap is a very useful method to repair small or medium defects at the temporal hairline. This flap can be flexibly designed and easily performed with a high survival rate and good aesthetic results. It provides another surgical option for complicated reconstruction.

Electrochemical Conjugation of Aptamers on a Carbon Fiber Microelectrode Enables Highly Stable and Selective In†Vivo Neurosensing.

Interfacing aptamers with carbon fiber microelectrodes (CFEs) provides a versatile platform to probe the chemical activity in a living brain at the molecular level. However, new approaches are needed for the efficient and stable modification of electrode surfaces with aptamers. Here, we present an electrochemical conjugation strategy to covalently couple aptamers onto CFEs with high chemoselectivity, efficiency, and stability for sensing in the brain. The strategy employs an initial electrochemical coupling of catechol on an CFE, thereby generating a thin layer of quinone intermediates that couple rapidly with thiol-containing oligonucleotides under a controlled potential. This approach dramatically simplifies and improves the efficiency for modifying carbon surfaces, thereby allowing direct conjugation of high levels of aptamers on CFEs within 5 minutes. Importantly, the covalent linkage between the aptamers and carbon surfaces enables a greatly improved sensitivity and stability for the sensing of dopamine, offering a robust system for continuously probing dopamine dynamics in the living brains of animals.

[Progress in application of Bletilla striata polysaccharide in novel drug delivery systems and biomaterials].

As the main active ingredient of the orchidaceous herb Bletilla striata, B. striata polysaccharide(BSP) has pharmacological activities such as promoting coagulation, anti-inflammation, anti-oxidation, promoting wound healing, anti-tumor, and immunomodulation, and is biodegradable and non-toxic. Additionally, it has the material properties of suspension thickening, film-forming adhesion, coating and solubilizing, targeting and slow releasing, effect-enhancing and toxicity-reducing, etc., playing the role of unification of medicines and excipients. Therefore, BSP has a wide application prospect in the fields of drug delivery system and trauma repair. This paper reviews the research progress of BSP application in new drug delivery systems and biomaterials based on the related li-terature in recent years, with the aim of providing reference for the further research and application of BSP.

IL-10 secreting B cells regulate periodontal immune response during periodontitis.

Periodontitis is a disease caused by periodontopathogens and is characterized by periodontal inflammation and alveolar bone resorption. As has been proven, host immune responses incite the development and progression of periodontitis. The present study sought to establish B10 cell functions and mechanisms in regulating host immunity during periodontitis. Periodontopathogen-specific B10 cells were purified and then injected into recipients to create the adoptive transfer models. We compared inflammatory cytokines and regulatory T (Treg)/Th17 cell expression in a healthy, normal model, an experimental periodontitis model, and experimental periodontitis model adoptively transferred with B10 cells. Compared with experimental periodontitis animals, our results showed that transfer of B10 cells alleviated alveolar bone resorption (P < 0.05) by reducing periodontal osteoclastogenesis (P < 0.05). Additionally, we found that B10 cell transfer into the experimental periodontitis ones resulted in increased IL-10 (P < 0.05), but decreased IL-17 (P < 0.05) and receptor activator for nuclear factor κB ligand (RANKL) (P < 0.05) gene and protein expression in local lesions. Moreover, adoptive transfer of B10 cells reduced the proportion of Th17 cells (P < 0.05) in the gingiva. The results of our study confirmed that B10 cells can modulate local host immune responses and prevent inflammatory damage of alveolar bone by reducing pro-inflammatory cytokine expression and decreasing local proliferation of Th17 cells.

Extracellular vesicles in bone and tooth: A state-of-art paradigm in skeletal regeneration.

Bone and tooth, fundamental parts of the craniofacial skeleton, are anatomically and developmentally interconnected structures. Notably, pathological processes in these tissues underwent together and progressed in multilevels. Extracellular vesicles (EVs) are cell-released small organelles and transfer proteins and genetic information into cells and tissues. Although EVs have been identified in bone and tooth, particularly EVs have been identified in the bone formation and resorption, the concrete roles of EVs in bone and tooth development and diseases remain elusive. As such, we review the recent progress of EVs in bone and tooth to highlight the novel findings of EVs in cellular communication, tissue homeostasis, and interventions. This will enhance our comprehension on the skeletal biology and shed new light on the modulation of skeletal disorders and the potential of genetic treatment.

Improved RANKL expression and osteoclastogenesis induction of CD27+CD38- memory B cells: A link between B cells and alveolar bone damage in periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis is a bacteria-induced disease that often leads to alveolar bone damage. Its mechanisms were considered to be complicated, involving an imbalance of the formation and resorption of bone. We sought to disclose the antibody-independent function of B cells during periodontitis. MATERIAL AND METHODS: Production of receptor activator for nuclear factor-κB ligand (RANKL) by total lymphocytes or sorted B-cell subsets in gingiva from healthy or experimental periodontitis animals was examined by flow cytometry, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay. To define the effects of lymphocytes or B-cell subsets on osteoclastogenesis induction, bone marrow mononuclear cells were culture in culture medium of lymphocytes or cocultured with B-cell subsets. Osteoclasts were enumerated by tartrate-resistant acid phosphatase staining. Constituent ratio of B-cell subsets in healthy or experimental periodontitis was also detected by flow cytometry. RESULT: Gingiva B cells produce more RANKL and support more osteoclastogenesis than T and other lymphocytes, and this potential improved in periodontitis. Memory B cells (CD27+CD38-) decreased their percentage in periodontitis. Memory B cells have the highest propensity for RANKL production. Remarkably, memory B cells from periodontitis animals expressed significantly more RANKL compared to healthy controls. Memory B cells supported osteoclast differentiation in vitro in a RANKL-dependent manner, and the number of osteoclasts was higher in cultures with memory B cells from periodontitis animals than in those derived from healthy ones. Other B-cell subsets have limited impact on osteoclast formation. CONCLUSION: Findings of this study further disclose the roles of B cells engaged in periodontal immunomodulation and reveal the considerable importance of memory B cells in alveolar bone homeostasis and their likely contribution to alveolar bone destruction in periodontitis.

Synthesis of Starch-Based Amphiphilic Fluorescent Nanoparticles and Their Application in Biological Imaging.

Due to the extensive source, good biocompatibility and biodegradability, the starch of carbohydrates has been extensively investigated for application in biological field. Recently, the development of fluorescent organic nanoparticles (FONs) on the basis of aggregation induced emission (AIE) dyes has attracted great research interest. In this article, novel starch-based S-TPEV polymers with AIE property were successfully fabricated by atom transfer radical polymerization (ATRP) of TPEV dye into water-soluble starch for the first time, subsequently, their structure and properties were detailedly investigated by 1H NMR, TEM, UV-vis, FL and FTIR. The characterization results confirmed the successful synthesis of S-TPEV polymers, and the molar fraction of TPEV and C6H10O5 ring in the starch polymers could be respectively calculated as approximate 5.8% and 94.2%. In aqueous solution, the as-prepared S-TPEV polymers will tend to self-assemble into FONs with 100-200 nm diameters, and their fluorescence intensity increased with the increase of the concentration of water in the mixed solution of water and DMSO, indicative of the obvious AIE property. More importantly, owing to their high water dispersity, good fluorescence and excellent biocompatibility, the S-TPEV FONs can be uptaken by HepG2 cells and show promising application in biological imaging field.

The Influence of Cellulosic Polymer's Variables on Dissolution/Solubility of Amorphous Felodipine and Crystallization Inhibition from a Supersaturated State.

The collective impact of cellulosic polymers on the dissolution, solubility, and crystallization inhibition of amorphous active pharmaceutical ingredients (APIs) is still far from being adequately understood. The goal of this research was to explore the influence of cellulosic polymers and incubation conditions on enhancement of solubility and dissolution of amorphous felodipine, while inhibiting crystallization of the drug from a supersaturated state. Variables, including cellulosic polymer type, amount, ionic strength, and viscosity, were evaluated for effects on API dissolution/solubility and crystallization processes. Water-soluble cellulosic polymers, including HPMC E15, HPMC E5, HPMC K100-LV, L-HPC, and MC, were studied. All cellulosic polymers could extend API dissolution and solubility to various extents by delaying crystallization and prolonging supersaturation duration, with their effectiveness ranked from greatest to least as HPMC E15 > HPMC E5 > HPMC K100-LV > L-HPC > MC. Decreased polymer amount, lower ionic strength, or higher polymer viscosity tended to decrease dissolution/solubility and promote crystal growth to accelerate crystallization. HPMC E15 achieved greatest extended API dissolution and maintenance of supersaturation from a supersaturated state; this polymer thus had the greatest potential for maintaining sustainable API absorption within biologically relevant time frames.

[Limb torsion and developmental regression for one month after hand, foot and mouth disease in an infant].

A one-year-old girl visited the hospital due to limb torsion and developmental regression for one month after hand, foot and mouth disease. At the age of 11 months, she visited a local hospital due to fever for 5 days and skin rash with frequent convulsions for 2 days and was diagnosed with severe hand, foot and mouth disease, viral encephalitis, and status epilepticus. Brain MRI revealed symmetric abnormal signals in the bilateral basal ganglia, bilateral thalamus, cerebral peduncle, bilateral cortex, and hippocampus. She was given immunoglobulin, antiviral drugs, and anticonvulsant drugs for 2 weeks, and the effect was poor. Blood and urine screening for inherited metabolic diseases were performed to clarify the etiology. The analysis of urine organic acids showed significant increases in glutaric acid and 3-hydroxyglutaric acid, which suggested glutaric aciduria type 1, but her blood glutarylcarnitine was normal, and free carnitine significantly decreased. After the treatment with low-lysine diets, L-carnitine, and baclofen for 1 month, the patient showed a significant improvement in symptoms. Hand, foot and mouth disease is a common viral infectious disease in children, and children with underlying diseases such as inherited metabolic diseases and immunodeficiency may experience serious complications. For children with hand, foot and mouth disease and unexplained encephalopathy, inherited metabolic diseases should be considered.

Beam scanning for rapid coherent Raman hyperspectral imaging.

Coherent Raman imaging requires high-peak power laser pulses to maximize the nonlinear multiphoton signal generation, but accompanying photo-induced sample damage often poses a challenge to microscopic imaging studies. We demonstrate that beam scanning by a 3.5-kHz resonant mirror in a broadband coherent anti-Stokes Raman scattering (BCARS) imaging system can reduce photo-induced damage without compromising signal intensity. Additionally, beam scanning enables slit acquisition, in which spectra from a thin line of sample illumination are acquired in parallel during a single charge-coupled device exposure. Reflective mirrors are employed in the beam-scanning assembly to minimize chromatic aberration and temporal dispersion. The combined approach of beam scanning and slit acquisition is compared with the sample-scanning mode in terms of spatial resolution, photo-induced damage, and imaging speed at the maximum laser power below the sample-damage threshold. We show that the beam-scanning BCARS imaging method can reduce photodamage probability in biological cells and tissues, enabling faster imaging speed by using a higher excitation laser power than could be achieved without beam scanning.

Deoxycholic acid-grafted PEGylated chitosan micelles for the delivery of mitomycin C.

Mitomycin C (MTC) was incorporated to a micelle system preparing from a polymer named deoxycholic acid chitosan-grafted poly(ethylene glycol) methyl ether (mPEG-CS-DA). mPEG-CS-DA was synthesized and characterized by (1)H nuclear magnetic resonance ((1)H-NMR) and Fourier transform infrared spectroscopy. mPEG-CS-DA formed a core-shell micellar structure with a critical micelle concentration of 6.57 µg/mL. The mPEG-CS-DA micelles were spherical with a hydrodynamic diameter of about 231 nm. After poly(ethylene glycol)ylation of deoxycholic acid chitosan (CS-DA), the encapsulation efficiency and drug loading efficiency increased from 50.62% to 56.42% and from 20.51% to 24.13%, respectively. The mPEG-CS-DA micelles possessed a higher drug release rate than the CS-DA micelles. For pharmacokinetics, the area under the curve (AUC) of the mPEG-CS-DA micelles was 1.5 times higher than that of MTC injection, and these micelles can enhance the bioavailability of MTC. mPEG-CS-DA micelles reduced the distribution of MTC in almost all normal tissues and had the potential to improve the kidney toxicity caused by MTC injection.

Profiling lipid-protein interactions using nonquenched fluorescent liposomal nanovesicles and proteome microarrays.

Fluorescent liposomal nanovesicles (liposomes) are commonly used for lipid research and/or signal enhancement. However, the problem of self-quenching with conventional fluorescent liposomes limits their applications because these liposomes must be lysed to detect the fluorescent signals. Here, we developed a nonquenched fluorescent (NQF)1 liposome by optimizing the proportion of sulforhodamine B (SRB) encapsulant and lissamine rhodamine B-dipalmitoyl phosphatidylethanol (LRB-DPPE) on a liposomal surface for signal amplification. Our study showed that 0.3% of LRB-DPPE with 200 µm of SRB provided the maximal fluorescent signal without the need to lyse the liposomes. We also observed that the NQF liposomes largely eliminated self-quenching effects and produced greatly enhanced signals than SRB-only liposomes by 5.3-fold. To show their application in proteomics research, we constructed NQF liposomes that contained phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) and profiled its protein interactome using a yeast proteome microarray. Our profiling led to the identification of 162 PI(3,5)P2-specific binding proteins (PI(3,5)P2-BPs). We not only recovered many proteins that possessed known PI(3,5)P2-binding domains, but we also found two unknown Pfam domains (Pfam-B_8509 and Pfam-B_10446) that were enriched in our dataset. The validation of many newly discovered PI(3,5)P2-BPs was performed using a bead-based affinity assay. Further bioinformatics analyses revealed that the functional roles of 22 PI(3,5)P2-BPs were similar to those associated with PI(3,5)P2, including vesicle-mediated transport, GTPase, cytoskeleton, and kinase. Among the 162 PI(3,5)P2-BPs, we found a novel motif, HRDIKP[ES]NJLL that showed statistical significance. A docking simulation showed that PI(3,5)P2 interacted primarily with lysine or arginine side chains of the newly identified PI(3,5)P2-binding kinases. Our study showed that this new tool would greatly benefit profiling lipid-protein interactions in high-throughput studies.

Exosomal miR-205-5p derived from periodontal ligament stem cells attenuates the inflammation of chronic periodontitis via targeting XBP1.

INTRODUCTION: Chronic periodontitis (CP) is an inflammatory periodontal disease with high incidence and complex pathology. This research is aimed to investigate the function of exosomal miR-205-5p (Exo-miR-205-5p) in CP and the underlying molecular mechanisms. METHOD: Exo-miR-205-5p was isolated from miR-205-5p mimics-transfected periodontal ligament stem cells (PDLSCs), and subsequently cocultured with lipopolysaccharide (LPS)-induced cells or injected into LPS-treated rats. The mRNA expression of inflammatory factors and Th17/Treg-related factors were measured by quantitative real-time PCR. The contents of inflammatory factors and the percentages of Th17/Treg cells were measured by enzyme-linked immunosorbent assay and flow cytometry, respectively. Besides, the target relation between miR-205-5p and X-box binding protein 1 (XBP1) was explored. RESULTS: MiR-205-5p was downregulated in LPS-induced PDLSCs and corresponding exosomes. Exo-miR-205-5p inhibited inflammatory cell infiltration, decreased the production of TNF-α, IL-1ß, and IL-6, and decreased the percentage of Th17 cells in LPS-treated rats. In addition, XBP1 was a target of miR-205-5p. Overexpression of XBP1 weakened the effects of Exo-miR-205-5p on inhibiting inflammation and regulating Treg/Th17 balance in LPS-induced cells. CONCLUSIONS: Exo-miR-205-5p derived from PDLSCs relieves the inflammation and balances the Th17/Treg cells in CP through targeting XBP1.

Advances in the prevention and treatment of Alzheimer's disease based on oral bacteria.

With the global population undergoing demographic shift towards aging, the prevalence of Alzheimer's disease (AD), a prominent neurodegenerative disorder that primarily afflicts individuals aged 65 and above, has increased across various geographical regions. This phenomenon is accompanied by a concomitant decline in immune functionality and oral hygiene capacity among the elderly, precipitating compromised oral functionality and an augmented burden of dental plaque. Accordingly, oral afflictions, including dental caries and periodontal disease, manifest with frequency among the geriatric population worldwide. Recent scientific investigations have unveiled the potential role of oral bacteria in instigating both local and systemic chronic inflammation, thereby delineating a putative nexus between oral health and the genesis and progression of AD. They further proposed the oral microbiome as a potentially modifiable risk factor in AD development, although the precise pathological mechanisms and degree of association have yet to be fully elucidated. This review summarizes current research on the relationship between oral bacteria and AD, describing the epidemiological and pathological mechanisms that may potentially link them. The purpose is to enrich early diagnostic approaches by incorporating emerging biomarkers, offering novel insights for clinicians in the early detection of AD. Additionally, it explores the potential of vaccination strategies and guidance for clinical pharmacotherapy. It proposes the development of maintenance measures specifically targeting oral health in older adults and advocates for guiding elderly patients in adopting healthy lifestyle habits, ultimately aiming to indirectly mitigate the progression of AD while promoting oral health in the elderly.

Characteristics of primary Sjögren's syndrome-associated peripheral nervous system lesions.

OBJECTIVE: The aim of this study is to investigate potential risk factors associated with peripheral nervous system lesions in primary Sjögren's syndrome (pSS) through a retrospective analysis of clinical manifestations, examination characteristics, and clinical electrophysiological features. MATERIALS AND METHODS: A retrospective case-control study was conducted at Nanfang Hospital, including 108 patients diagnosed with pSS following the criteria revised by the American College of Rheumatology in 2016. The study spanned from January 2015 to October 2020. The patient cohort was divided into two groups, an experimental group (N = 27) consisting of patients with primary Sjögren's syndrome-peripheral nervous system lesions (pSS-PNS), and a control group (N = 81) comprising patients without peripheral neurological impairment, i.e., primary Sjögren's syndrome-non peripheral nervous system lesions (pSS-nPNS). RESULTS: The results showed a significant correlation between immunoglobulin G (IgG), α-Fodrin immunoglobulin G (α-FIgG), platelet counts (PLT), dry mouth and peripheral neuropathy of Sjogren's syndrome (p < 0.01). The research also revealed that α-FIgG (OR 2.03; 95% CI 1.14-3.64), IgG (OR 1.23; 95% CI 1.06-1.42), and PLT (OR 1.01; 95% CI 1.00-1.01) were identified as risk factors for the onset of peripheral neuropathy of Sjogren's syndrome, while dry mouth had a negative correlation (OR 0.08; 95% CI 0.02-0.40). Remarkably, the total risk assessment of the independent variables demonstrated a high AUC (95%CI) of 0.923 (0.861-0.986; p < 0.001), indicating an excellent prediction of pSS-PNS occurrence through the ROC analysis. Additionally, high platelet counts and strong positive anti-SSB antibody titer were found to be risk factors for dual motor and sensory nerve damages among pSS-PNS patients. CONCLUSION: IgG, α-FIgG, and PLT were identified as independent risk factors for patients with pSS-PNS. The likelihood of peripheral neuropathy appeared to increase in tandem with the elevated levels of above three factors. Interestingly, we found that dry mouth might play a protective role in this context. Our study further noted that both high platelet counts and strong positive anti-SSB antibody titer may be associated with increased risk of both motor and sensory nerve involvement in pSS-PNS patients. These findings have significant implications for both the etiologies and therapeutics of pSS-PNS.

Matching mechanical heterogeneity of the native spinal cord augments axon infiltration in 3D-printed scaffolds.

Scaffolds delivered to injured spinal cords to stimulate axon connectivity often match the anisotropy of native tissue using guidance cues along the rostral-caudal axis, but current approaches do not mimic the heterogeneity of host tissue mechanics. Although white and gray matter have different mechanical properties, it remains unclear whether tissue mechanics also vary along the length of the cord. Mechanical testing performed in this study indicates that bulk spinal cord mechanics do differ along anatomical level and that these differences are caused by variations in the ratio of white and gray matter. These results suggest that scaffolds recreating the heterogeneity of spinal cord tissue mechanics must account for the disparity between gray and white matter. Digital light processing (DLP) provides a means to mimic spinal cord topology, but has previously been limited to printing homogeneous mechanical properties. We describe a means to modify DLP to print scaffolds that mimic spinal cord mechanical heterogeneity caused by variation in the ratio of white and gray matter, which improves axon infiltration compared to controls exhibiting homogeneous mechanical properties. These results demonstrate that scaffolds matching the mechanical heterogeneity of white and gray matter improve the effectiveness of biomaterials transplanted within the injured spinal cord.

Farmers' participation into the recovery of waste agricultural plastic film: An application of the Theory of Planned Behavior.

This study aims to address the lack of relevant researches in the field of waste recycling using the Theory of Planned Behavior (TPB). A village-scale social survey was conducted to investigate the degree of farmers' participation in a waste plastic film program, i.e. Old for New in northwest China. The program required farmers to recycle plastic film residues in exchange for new films. Survey results showed that 67.5% of farmers accepted the program, yet only 14.5% of them actually participated. Logistic regression analysis was used to analyze questionnaire data and identify the factors that significantly affected farmers' recycling behavior. Principal component and weight analysis further showed that farmers' participation was mainly influenced by their attitudes (p < 0.01), with a relative weight (RW) of 46.3%. Yet, subjective norms (p < 0.1) and perceived behavior control (p < 0.1) had less effect on the degree of participation, and their RWs were 4.2% and 4.1% only, respectively. Moreover, the RW of plastic film usage characteristics and household characteristics reached up to 13.2% and 6.4%, respectively. Interestingly, environmental awareness (ß = 0.083) and compulsory environmental education (ß = 0.130) as surface factors strongly affected the farmers' adoption and response, with the RW of 25.7%. As such, the extended TPB model was established to analyze the participation behavior of farmers for stronger explanatory power. This study highlighted a promising strategy based on TPB for waste plastic film recycling and similar environmental management practices.

Facile and efficient fabrication of photoresponsive microgels via thiol-Michael addition.

A photoresponsive microgel is designed by the combination of a noncovalent assembly strategy with a covalent cross-linking method. End-functionalized poly(ethylene glycol) with azobenzene [(PEG-(Azo)(2))] was mixed with acrylate-modified ß-CD (ß-CD-MAA) to form photoresponsive inclusion complex through host-guest interaction. The above photoresponsive complex was cross-linked by thiol-functionalized PEG (PEG-dithiol) via Michael addition click reaction. The photoreversibility of resulted microgel was studied by TEM, UV-Vis spectroscopy, and (1)H NMR measurements. The characterization results indicated that the reversible size changes of the microgel could be achieved by alternative UV-Vis irradiations with good repeatability.