The role of vitamin D receptor in predentin mineralization and dental repair after injury.

Dentin is a permeable and complex tubular composite formed by the mineralization of predentin that mineralization and repair are of considerable clinical interest during dentin homeostasis. The role of Vdr, a receptor of vitamin D, in dentin homeostasis remains unexplored. The aim of the present study was to assess the impact of Vdr on predentin mineralization and dental repair. Vdr-knockout (Vdr-/-) mice models were constructed; histology and immunohistochemistry analyses were conducted for both WT and Vdr-/- mice. The finding revealed a thicker predentin in Vdr-/- mice, characterized by higher expression of biglycan and decorin. A dental injury model was employed to observe tertiary dentin formation in Vdr-/- mice with dental injuries. Results showed that tertiary dentin was harder to form in Vdr-/- mice with dental injury. Over time, heightened pulp invasion was observed at the injury site in Vdr-/- mice. Expression of biglycan and decorin was reduced in the predentin at the injury site in the Vdr-/- mice by immunohistochemistry. Taken together, our results imply that Vdr plays a regulatory role in predentin mineralization and tertiary dentin formation during dentin homeostasis.

Polyacrylic acid-reinforced organic-inorganic composite bone adhesives with enhanced mechanical properties and controlled degradability.

Bone adhesives, as alternatives to traditional bone fracture treatment methods, have great benefits in achieving effective fixation and healing of fractured bones. However, current available bone adhesives have limitations in terms of weak mechanical properties, low adhesion strength, and inappropriate degradability, hindering their clinical applications. The development of bone adhesives with strong mechanical properties, adhesion strength, and appropriate degradability remains a great challenge. In this study, polyacrylic acid was incorporated with tetracalcium phosphate and O-phospho-L-serine to form a new bone adhesive via coordination and ionic interactions to achieve exceptional mechanical properties, adhesion strength, and degradability. The bone adhesive could achieve an initial adhesion strength of approximately 3.26 MPa and 0.86 MPa on titanium alloys and bones after 15 min of curing, respectively, and it increased to 5.59 MPa and 2.73 MPa, after 24 h of incubation in water or simulated body fluid (SBF). The compressive strength of the adhesive increased from 10.06 MPa to 72.64 MPa over two weeks, which provided sufficient support for the fractured bone. Importantly, the adhesive started to degrade after 6 to 8 weeks of incubation in SBF, which is beneficial to cell ingrowth and the bone healing process. In addition, the bone adhesives exhibited favorable mineralization capability, biocompatibility, and osteogenic activity. In vivo experiments showed that it has a better bone-healing effect compared with the traditional polymethyl methacrylate bone cement. These results demonstrate that the bone adhesive has great potential in the treatment of bone fractures.

Preparation of high elastic bacterial cellulose aerogel through thermochemical vapor deposition catalyzed by solid acid for oil-water separation.

Oil pollution has caused more and more serious damages to the environment, especially to water. Oil and water separation technologies based on high-performance absorbing materials have attracted extensive attentions. Herein, elasticity-enhanced bacterial cellulose (BC) aerogel is synthesized for oil/water separation through thermochemical vapor deposition (CVD) catalyzed by 1, 2, 3, 4-butanetetracarboxylic acid (BTCA). BTCA has two functions, namely, esterification with BC and catalyzing CVD. The prepared aerogel could be recovered soon after being compressed and the elastic recovery was >90 % at set maximum deformation of 80 %. And, it also exhibits vigorous fatigue resistance with an elastic deformation of >80 % after 50 cycles. The high elastic and hydrophobic aerogel is very suitable for absorbing and desorbing oils by simple mechanical squeezing. The adsorption capacity for n-hexane and dichloroethane maintain 87 % and 81 % after 50 cycles, respectively, which implies robust reusability. Importantly, the CVD could also be catalyzed by other solid acids such as citric acid and vitamin C. This design and fabrication method offers a novel avenue for the preparation of hydrophobic bacterial cellulose aerogel with high elasticity.

Stability of SARS-CoV-2 in cold-chain transportation environments and the efficacy of disinfection measures.

Background: Low temperature is conducive to the survival of COVID-19. Some studies suggest that cold-chain environment may prolong the survival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and increase the risk of transmission. However, the effect of cold-chain environmental factors and packaging materials on SARS-CoV-2 stability remains unclear. Methods: This study aimed to reveal cold-chain environmental factors that preserve the stability of SARS-CoV-2 and further explore effective disinfection measures for SARS-CoV-2 in the cold-chain environment. The decay rate of SARS-CoV-2 pseudovirus in the cold-chain environment, on various types of packaging material surfaces, i.e., polyethylene plastic, stainless steel, Teflon and cardboard, and in frozen seawater was investigated. The influence of visible light (wavelength 450 nm-780 nm) and airflow on the stability of SARS-CoV-2 pseudovirus at -18°C was subsequently assessed. Results: Experimental data show that SARS-CoV-2 pseudovirus decayed more rapidly on porous cardboard surfaces than on nonporous surfaces, including polyethylene (PE) plastic, stainless steel, and Teflon. Compared with that at 25°C, the decay rate of SARS-CoV-2 pseudovirus was significantly lower at low temperatures. Seawater preserved viral stability both at -18°C and with repeated freeze-thaw cycles compared with that in deionized water. Visible light from light-emitting diode (LED) illumination and airflow at -18°C reduced SARS-CoV-2 pseudovirus stability. Conclusion: Our studies indicate that temperature and seawater in the cold chain are risk factors for SARS-CoV-2 transmission, and LED visible light irradiation and increased airflow may be used as disinfection measures for SARS-CoV-2 in the cold-chain environment.

Effects of Zn-In-Sn elements on the electric properties of magnesium alloy anode materials.

A new magnesium alloy anode is based on an environmentally friendly electrode that contains none of mercury, lead and chromate, but it can enhance the electric properties of alloy significantly. Magnesium alloy adding eco-friendly elements Zn-In-Sn which was developed by orthogonal design were obtained by two casting methods. The effect of additive elements on performance of electrode material was studied. The effects of elements addition and casting method on electric properties and corrosive properties of Mg-Zn-In-Sn alloys were investigated by using electrochemical measurements, corrosive tests and observation of surface structure. The results show that Mg-Zn-In-Sn alloy anode has higher electromotive force and more stable work potential than that commercial magnesium alloy AZ91. It is suitable for anode material of magnesium battery for its small hydrogen evolution, less self-corrosion rate and easy to shed corrosive offspring off.

Removal and biotransformation pathway of antibiotic sulfamethoxazole from municipal wastewater treatment by anaerobic membrane bioreactor.

A lab-scale mesophilic anaerobic membrane bioreactor (AnMBR) was used to treat synthetic municipal wastewater with variable concentrations of antibiotic Sulfamethoxazole (SMX) and bulk organics in this study. The removal and biotransformation pathway of SMX in the AnMBR were systematically investigated during a 170 d of operation under hydraulic retention time of 1 d. Average SMX removal was 97.1% under feed SMX of 10-1000 µg/L, decreasing to 91.6 and 88.0% under feed SMX of 10,000 and 100,000 µg/L due to the inhibition effects of high SMX loading rate on anaerobic microorganisms. SMX biotransformation followed pseudo-first order reaction kinetics based on SMX removal independent of feed SMX of 10-1000 µg/L during continuous operation and also in a batch test under initial SMX of 100,000 µg/L. According to the identified 7 transformation products (TPs) by gas chromatography-mass spectrometry, the biotransformation pathway of SMX from municipal wastewater treatment via AnMBR was first proposed to consist of 2 primary routes: 1) Butylbenzenesulfonamide without antibiotic toxicity dominated under feed SMX of 10-100 µg/L; 2) Sulfanilamide with much lower antibiotic toxicity than SMX dominated under feed SMX of 1000-100000 µg/L, further transforming to secondary TPs (4-Aminothiophenol, Aniline, Acetylsulfanilamide) and tertiary TPs (4-Acetylaminothiophenol, Acetylaniline).

[Effect of prehospital intervention based on emergency medical services on door-to-needle time of thrombolysis in acute ischemic stroke].

OBJECTIVE: To investigate the prehospital intervention based on emergency medical services (EMS) in patients with acute ischemic stroke (AIS) for door-to-needle time (DNT) with intravenous thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA) impact. METHODS: 112 emergency patients receiving rt-PA intravenous thrombolysis admitted to the First Hospital of Qinhuangdao City based on EMS from June 2016 to December 2017 were enrolled. According to whether or not to receive prehospital interventions, patients were divided into prehospital intervention group (n = 42) and routine treatment group (n = 70). Both groups followed the general principles of first aid, including assessment and support of the airway, respiration, and circulation, and blood glucose, electrocardiogram, and dynamic vital signs were monitored. Based on the general principle of EMS, first-aid personnel in the prehospital intervention group screened suspected acute stroke patients requiring prehospitalization according to Los Angeles prehospital stroke screening table (LAPSS), and established fluid ways, and got blood samples to evaluate rt-PA intravenous thrombolysis and risks. Factors influenced DNT compliance were analyzed through multivariate Logistic regression, which included the education level of the patient, whether there were risk factors related to cerebrovascular disease (hypertension, coronary heart disease, diabetes), visit time, National Institute of Health stroke scale (NIHSS) score, whether received EMS intervention or not. The average DNT, DNT ≤ 60 minutes compliance rate, communication time, and decision time for thrombolysis were compared between the two groups. NIHSS score was used to evaluate the effective rate of thrombolysis for 7 days. The modified Rankin score (mRs) was used to evaluate the neurological function after 3 months of thrombolysis (a mRs score of 0-2 was defined as a good nerve function). RESULTS: Univariate analysis showed that the DNT of patients with NIHSS score > 5 was significantly shorter than those with NIHSS score ≤ 5, and DNT in patients received EMS intervention was significantly shorter than the non-receiver; but education level, visiting time, and risk factors associated with cerebrovascular disease had nothing to do with DNT. Multivariate Logistic regression analysis showed that NIHSS score and EMS intervention were the influencing factors of DNT compliance [NIHSS score: odds ratio (OR) = 0.452, 95% confidence interval (95%CI) = 0.162-1.263, P = 0.030; EMS intervention: OR = 3.077, 95%CI = 1.260-7.514, P = 0.014]. Compared with conventional treatment group, DNT of intravenous thrombolytic in prehospital intervention group was significantly shortened (minutes: 62.00±11.07 vs. 78.03±21.04), DNT ≤ 60 minutes compliance rate was significantly increased [35.7% (15/42) vs. 12.9% (9/70)], communication time [minutes: 4 (3, 6) vs. 6 (5, 9)] and decision-making thrombolytic time (minutes: 5.81±2.48 vs. 6.70±2.15) were significantly shortened, the differences were statistically significant (all P < 0.05). The 7-day effective rate in the prehospital intervention group [33.3% (14/42) vs. 14.3% (10/70), χ2 = 5.657, P = 0.017] and the 3-mouth good rate of nerve function [38.1% (16/42) vs. 14.3% (10/70), χ2 = 10.759, P = 0.001] were significantly higher than those in the conventional treatment group. CONCLUSIONS: Prehospital interventions based on EMS can shorten DNT of intravenous thrombolysis in the patients with AIS, improve treatment efficiency, and improve prognosis.

Polydimethylsiloxane incorporated with reduced graphene oxide (rGO) sheets for wound dressing application: Preparation and characterization.

Toward fabricating a novel multifunctional wound dressing material, we incorporated a series of contents of reduced graphene oxide (rGO) sheets into polydimethylsiloxane (PDMS) matrix to prepare the rGO-PDMS composite membrane and be used for wound dressing. The pore structure, dispersion of rGO, physical properties, water vapor transmission rate (WVTR), cytotoxicity and antibacterial activity were studied. Finally, the effect of the rGO-PDMS composite membrane on wound healing was investigated on a murine full-thickness skin wound model. The rGO-PDMS composite membrane exhibited bionic performance (ordered pore structure and suitable WVTR), improved mechanical properties, good compatibility and effective antibacterial activity. In vivo experiment indicated that the rGO-PDMS composite membrane could accelerate wound healing via enhancement of the re-epithelialization and granulation tissue formation. These findings suggest that rGO doping PDMS uniquely resulted in a multifunctional material for potential use in wound dressing.

Thrombospondin-1 Production Regulates the Inflammatory Cytokine Secretion in THP-1 Cells Through NF-κB Signaling Pathway.

Thrombospondin-1 (TSP-1) is upregulated in several inflammatory diseases. Recent data have shown that macrophages from TSP-1-deficient mice have a reduced inflammatory phenotype, suggesting that TSP-1 plays a part in macrophage activation. DNA microarray approach revealed that Porphyromonas gingivalis lipopolysaccharide (P. gingivalis LPS) may induce the enhanced TSP-1 expression in human monocytes, suggesting a role of TSP-1-mediated pathogenesis in periodontitis. Until recently, the function of TSP-1 has been a matter of debate. In this study, we explored the role of TSP-1 in inflammatory cytokine secretions and its putative mechanism in pathogenesis of periodontitis. We demonstrated that TSP-1 expression was significantly upregulated in gingival tissues with periodontitis and in P. gingivalis LPS-stimulated THP-1 cells. Deficiency of TSP-1 by transfecting siRNAs decreased IL-6, IL-1ß, and TNF-α secretions in THP-1 cells, whereas overexpression of TSP-1 resulted in an upregulation of IL-6, IL-1ß, and TNF-α productions. Additional experiments showed that Pyrrolidine dithiocarbamate (PDTC) inhibited IL-6, IL-1ß, and TNF-α expression induced by overexpression of TSP-1, accompanying with downregulation of phosphorylated p65 and IκBα protein levels in response to P. gingivalis LPS. These results indicated that TSP-1 played a significant role in P. gingivalis LPS-initiated inflammatory cytokines (IL-6, IL-1ß, and TNF-α) secretions of THP-1 cells, and the NF-κB signaling is involved in its induction of expression. Thus, TSP-1 effectively elevated P. gingivalis LPS-induced inflammation mediated by the NF-κB pathway and may be critical for pathology of periodontitis.