Enhanced metal-free photocatalyst performance by synergistic Coupling of internal magnetic field and piezoelectric field.

Graphitic carbon nitride (g-C3N4) is a promising metal-free photocatalyst; however, its high carrier recombination rate and insufficient redox capacity limit its degradation effect on antibiotics. In order to overcome these shortcomings, the photocatalytic activity is improved by regulating the spin polarization state, constructing the internal electric field, and applying the external piezoelectric field. In this paper, the chlorine-doped and nitrogen-deficient porous carbon nitride composite carbon quantum dots (Nv-Cl/UPCN@CQD) has been synthesized successfully. The doping position of chlorine and spin polarization properties are verified by DFT calculation. The key intermediates *O2- and *OOH for the synthesis of reactive oxygen species were detected by in-situ infrared testing, which promotes the production of •O2- and H2O2. The degradation rate constant of Nv-Cl/UPCN@CQD for removal of tetracycline is 8.45 times higher than that of g-C3N4. The active oxygen production and degradation efficiency of piezoelectric photocatalysis under the synergistic effect of intense stirring and vis-light irradiation are much higher than those of photocatalysis and piezoelectric catalysis, and the conversion of H2O2 to •OH is promoted by piezoelectric field. This paper provides a reliable way to improve the performance of piezoelectric photocatalysts by adjusting their energy band, electronic structure and piezoelectric force.

Vacuum sealing drainage to treat Fournier's gangrene.

BACKGROUND: Vacuum sealing drainage (VSD) is widely applied in complex wound repair. We aimed to compare traditional debridement and drainage and VSD in treating Fournier's gangrene (FG). METHODS: Data of patients surgically treated for FG were retrospectively analyzed. RESULTS: Of the 36 patients (men: 31, women: 5; mean age: 53.5 ± 11.3 [range: 28-74] years) included in the study, no patients died. Between-group differences regarding sex, age, BMI, time from first debridement to wound healing, number of debridements, FGSI, and shock were not statistically significant (P > 0.05). However, lesion diameter, colostomy, VAS score, dressing changes, analgesic use, length of hospital stay, and wound reconstruction method (χ2 = 5.43, P = 0.04) exhibited statistically significant differences. Tension-relieving sutures (6 vs. 21) and flap transfer (4 vs. 2) were applied in Groups I and II, respectively. CONCLUSION: VSD can reduce postoperative dressing changes and analgesic use, and shrunk the wound area, thereby reducing flap transfer in wound reconstruction.

High-performance photocatalytic peroxymonosulfate activation by carbon quantum dots via precise surface chemistry regulation: Insight into the structure-function relations.

Carbon quantum dots (CQDs) are considered promising metal-free green catalysts for the activation of persulfates, but direct experimental evidence to identify the true active sites on the surface of CQDs is still lacking. We prepared CQDs with different oxygen contents by controlling the carbonisation temperature, using a simple pyrolysis method. Photocatalytic activity experiments show that CQDs200 exhibits the best PMS activation performance. By investigating the relationship between the oxygen functional groups on CQDs surface and photocatalytic activity, it was postulated that the C=O groups might be the predominant active site, which was confirmed by selective chemical titrations of the C=O, C-OH and COOH groups. Furthermore, limited to the weak photocatalytic properties of the pristine CQDs, ammonia and phenylhydrazine were used to precisely nitrogen-modify the o-CQD surface. We found that phenylhydrazine-modified o-CQDs-PH promoted the absorption of visible light and the separation of photocarriers, thus enhancing the activation of PMS. Theoretical calculations provide more insights from different levels of the pollutant, fine-tuned CQDs, and their interactions.

Enhanced adsorption and visible-light photocatalysis on TiO2 with in situ formed carbon quantum dots.

Carbon quantum dots (CQDs) can be used to modify TiO2 to extend the light absorption threshold and enhance its photocatalytic efficiency. In this study, different amounts of CQDs modified TiO2 (CQDs-x/TiO2) were synthesized by a facile, mild, and environmental friendly hydrothermal method at a low temperature. The physicochemical properties were investigated by a variety of advanced characterization techniques. It was found that the anchoring of CQDs endowed the CQDs-x/TiO2 with a large specific surface area, which is beneficial to adsorb more organic pollutants and promote the rate of photocatalytic oxidation. The XRD results also showed that the in situ formation of CQDs on the surface of TiO2 made the crystallinity of TiO2 tend to be complete. Among these photocatalysts, CQDs-20/TiO2 showed the highest pollutant removal efficiency under visible light irradiations. The classical quenching tests revealed that the O2•-, •OH, and hole (h+) were the oxidizing species. Among them, h+ was the primary factor contributing to the degradation. The electrochemical tests showed that the anchoring of CQDs on TiO2 increased the photocurrent by about four times, as compared with the pure TiO2. In particular, the cyclic voltammetry results showed that the photo-generated electrons of CQDs were freer to transfer to TiO2 under visible light irradiations, promoting the separation of photo-generated electrons and holes. This study explains adequately why the CQDs/TiO2 system has a good photocatalytic degradation of organic compounds.

Transanal Opening of Intersphincteric Space for Fistula-in-Ano.

BACKGROUND: The role of the intersphincteric space in the pathogenesis of fistula-in-ano is being increasingly recognized. Submucosal and intersphincteric rectal abscesses have been surgically managed by laying open and draining the intersphincteric space as well as by the modified ligation of intersphincteric fistula tract (LIFT) procedure. In 2017, the transanal opening of intersphincteric space (TROPIS) technique was reported for the treatment of high, complex anal fistulae. AIM: We aim to investigate the advantages of performing the TROPIS procedure in patients with fistula-in-ano. METHODS: This was a prospective cohort study investigating the outcomes in patients who had undergone a procedure using the TROPIS technique for the treatment of fistula-in-ano. Preoperative magnetic resonance imaging scans and electronic colonoscopies were performed on all patients. A clinical database evaluating the following variables was constructed: age, gender, body mass index (BMI), previous fistula surgery, type of fistula, postoperative complications, duration of follow-up, success rate, and incontinence scores pre- and postoperatively. RESULTS: The TROPIS procedure was performed on 41 patients with fistula-in-ano with a follow-up time of 6-23 months. The characteristics of the patients were as follows: 36 males, 6 females, mean age 38.6±13.2 years, and mean BMI 23.5±3.9 kg·m-2. All patients (41) had transsphincteric fistulae, and 90.2% (37) had high fistula. Of the 41 patients, 22% (9) had recurrent fistulae, 29.27% (12) had horseshoe fistulae, 7.3% (3) had supralevator fistulae, and 14.6% (6) had an associated abscess. The fistula healed completely in 85.3% (35) of patients and failed to heal in 14.7% (6) of patients, and the healing of high fistula was 86.5% (32). Of those patients who had not healed completely, 2 were found to have contracted iatrogenic infections due to foreign residues and underwent surgery with the passing of a loose seton. The additional 4 patients who had not healed underwent a fistulotomy and healed completely thereafter. There were no significant changes in incontinence scores. The incontinence scores were .15 ± .36 preoperatively and .22 ± .47 3 months postoperatively (t = -1.438, P = .16). CONCLUSIONS: The TROPIS technique is a novel sphincter-preserving procedure, which can be effectively used in treating fistula-in-ano.

Photocatalytic activation of peroxymonosulfate by surface-tailored carbon quantum dots.

In this study, carbon quantum dots (CQDs) were synthesized by a low-cost and scalable approach and the oxygen functional groups were fine-tuned by chemical post-treatment. It was found that the CQDs could be applied as visible-light-responsive photocatalysts for activation of peroxymonosulfate (PMS) and remediation of aqueous organic dyes. Phenylhydrazine modified CQDs (CQDs-PH) presented high efficiency for degradation of methylene blue due to selective removal of carboxylic groups and inhibited recombination of photogenerated electron-hole pairs. The effects of catalyst dosage, species and concentrations of dyes, and initial pH values on the photodegradation efficiency were systematically investigated and the alkaline condition facilitates the separation of photoinduced charge carriers and promotes the dye decoloration. The reactive oxygen species produced in the photocatalysis were identified by radical quenching tests and the mechanism was elucidated. Superoxide radicals were generated from PMS activation via electron transfer from CQDs and played the primary role in organic oxidation. In addition, photogenerated holes on the valence band of CQDs also participated in the dye decomposition.

Design and Synthesis of a New Mannitol Stearate Ester-Based Aluminum Alkoxide as a Novel Tri-Functional Additive for Poly(Vinyl Chloride) and Its Synergistic Effect with Zinc Stearate.

Thermal stabilizers, lubricant, and plasticizers are three crucial additives for processing poly(vinyl chloride) (PVC). In this study, a new mannitol stearate ester-based aluminum alkoxide (MSE-Al) was designed and synthesized as a novel additive for PVC. The thermal stability and processing performance of PVC stabilized by MSE-Al were evaluated by the Congo red test, conductivity measurement, thermal aging test, ultravioletevisible (UV-Vis) spectroscopy test, and torque rheometer test. Results showed that the addition of MSE-Al could not only markedly improve the long-term thermal stability of PVC, but also greatly accelerate the plasticizing and decrease the balance torque, which demonstrated that MSE-Al possessed a lubricating property. Thus, MSE-Al was demonstrated to be able to provide tri-functional additive roles, e.g., thermal stabilizer, plasticizer, and lubricant. The test results for the thermal stability of PVC indicated that the initial whiteness of PVC stabilized by MSE-Al was not good enough, thus the synergistic effect of MSE-Al with zinc stearates (ZnSt2) on the thermal stability of PVC was also investigated. The results showed that there is an appreciable synergistic effect between MSE-Al and ZnSt2. The thermal stabilization mechanism and synergism effect of MSE-Al with ZnSt2 are then discussed.

Facile Synthesis of Di-Mannitol Adipate Ester-Based Zinc Metal Alkoxide as a Bi-Functional Additive for Poly(Vinyl Chloride).

A new di-mannitol adipate ester-based zinc metal alkoxide (DMAE-Zn) was synthesized as a bi-functional poly(vinyl chloride) (PVC) thermal stabilizer for the first time. The materials were characterized with Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Characterization results confirmed the formation of Zn-O bonds in DMAE-Zn, and confirmed that DMAE-Zn had a high decomposition temperature and a low melting point. The thermal stability of DMAE-Zn on PVC also was tested by a conductivity test, a thermal aging test, and a UV-visible spectroscopy (UV-VIS) test. PVC stabilized by DMAE-Zn had a good initial color and excellent long-term stability. UV-VIS also showed that the conjugated structure in PVC stabilized by DMAE-Zn was almost all of the triene, suggesting that the addition of DMAE-Zn would suppress the formation of conjugated structures above tetraene. The dynamic processing performance of PVC samples tested by torque rheometer indicated that, having a good compatibility with PVC chains in the amorphous regions, DMAE-Zn contributed a good plasticizing effect to PVC. DMAE-Zn thus effectively demonstrates bi-functional roles, e.g., thermal stabilizers and plasticizers to PVC. Furthermore, FT-IR, a HCl absorption capacity test, and a complex ZnCl2 test were also used to verify the thermal stability mechanism of DMAE-Zn for PVC.

Thionin functionalized signal amplification label derived dual-mode electrochemical immunoassay for sensitive detection of cardiac troponin I.

A sensitive sandwich-type electrochemical immunosensor was established by employing Au@Pt core-shell multi-branched nanoparticles, and thionin functionalized nitrogen/sulfur co-doped graphene oxide (N/S-cGO/L-lys/Au@Pt MBs/Thi) as a double signal label to detect cardiac troponin I (cTnI). In this work, Au nanorods functionalized polydopamine (Au NR@PDA) with high adsorption capacity and superior electroconductivity can provide an efficient substrate for immobilizing primary antibodies (Ab1). In the proposed N/S-cGO/L-lys/Au@Pt MBs/Thi, an electrochemically active molecule, Thi was covalently bonded in the N/S-cGO/L-lys/Au@Pt MBs. It presented a strong differential pulse voltammetry (DPV) current signal without electron transfer mediators, and showed a high electrocatalytic activity toward H2O2 reduction by using amperometric i-t (i-t). Impressively, with the synergistic effect of N/S-cGO/L-lys/Au@Pt MBs/Thi and Au NR@PDA, the developed dual-mode electrochemical immunosensor for cTnI detection showed a wide linear concentration range (50 fg/mL to 250 ng/mL, 750 fg/mL to 100 ng/mL) and a low detection limit (16.7 fg/mL, 250 fg/mL) via i-t and DPV, respectively. Furthermore, this immunosensor exhibited acceptable reproducibility, high sensitivity and good stability under optimal conditions. More importantly, the satisfactory results were obtained in detection of cTnI-spiked human serum samples, and the presented method may be a promising application in clinical bioanalysis.

Oxygen Vacancies in Shape Controlled Cu2O/Reduced Graphene Oxide/In2O3 Hybrid for Promoted Photocatalytic Water Oxidation and Degradation of Environmental Pollutants.

A novel shape controlled Cu2O/reduced graphene oxide/In2O3 (Cu2O/RGO/In2O3) hybrid with abundant oxygen vacancies was prepared by a facile, surfactant-free method. The hybrid photocatalyst exhibits an increased photocatalytic activity in water oxidation and degradation of environmental pollutants (methylene blue and Cr6+ solutions) compared with pure In2O3 and Cu2O materials. The presence of oxygen vacancies in Cu2O/RGO/In2O3 and the formation of heterojunction between In2O3 and Cu2O induce extra diffusive electronic states above the valence band (VB) edge and reduce the band gap of the hybrid consequently. Besides, the increased activity of Cu2O/RGO/In2O3 hybrid is also attributed to the alignment of band edge, a process that is assisted by different Fermi levels between In2O3 and Cu2O, as well as the charge transfer and distribution onto the graphene sheets, which causes the downshift of VB of In2O3 and the significant increase in its oxidation potential. Additionally, a built-in electric field is generated on the interface of n-type In2O3 and p-type Cu2O, suppressing the recombination of photoinduced electron-hole pairs and allowing the photogenerated electrons and holes to participate in the reduction and oxidation reactions for oxidizing water molecules and pollutants more efficiently.

Oxygen functional groups in graphitic carbon nitride for enhanced photocatalysis.

Metal-free semiconductors offer a new opportunity for environmental photocatalysis toward a potential breakthrough in high photo efficiency with complete prevention of metal leaching. In this study, graphitic carbon nitride (GCN) modified by oxygen functional groups was synthesized by a hydrothermal treatment of pristine GCN at different temperatures with H2O2. Insights into the emerging characteristics of the modified GCN in photocatalysis were obtained by determining the optical properties, band structure, electrochemical activity and pollutant degradation efficiency. It was found that the introduction of GCN with oxygen functional groups can enhance light absorption and accelerate electron transfer so as to improve the photocatalytic reaction efficiency. The photoinduced reactive radicals and the associated photodegradation were investigated by in situ electron paramagnetic resonance (EPR). The reactive radicals, O2(-) and OH, were responsible for organic degradation.

Meta-analysis of oncological outcome after abdominoperineal resection or low anterior resection for lower rectal cancer.

In lower rectal cancer, postoperative outcome is still subject of controversy between the advocates of abdominoperineal resection (APR) and low anterior resection (LAR). Reports suggest that low anterior resection may be oncologically superior to abdominoperineal excision, although no good evidence exists to support this. Publications were identified which assessed the differences comparing 5-year survival, local recurrence, circumferential resection margin rate, complications and so on. A meta-analysis was performed to clarify the safety and feasibility of the two procedures with several types of outcome measures. A total of 13 studies met the inclusion criteria, and comprised 6,850 cases. Analysis of these data showed that LAR group was highly correlated with 5-year survival (pooled OR = 1.73, 95%CI: 1.30-2.29, P = 0.0002 random-effect). And local recurrence rate of APR group was significantly higher than that in LAR group (pooled OR = 0.63, 95%CI: 0.53-0.75, P < 0.00001 fixed-effect). Also, the circumferential resection margin (CRM) were high involved in APR group than in LAR group. (5 trials reported the data, pooled OR = 0.43, 95%CI: 0.36-0.52, P < 0.00001 fixed-effect). Besides, the incidents of overall complications of APR group was higher compared with LAR group (pooled OR = 0.52, 95%CI: 0.29-0.92, P = 0.03 random-effect). Patients treated by APR have a higher rate of CRM involvement, a higher local recurrence, and poorer prognosis than LAR. And there is evidence that in selected low rectal cancer patients, LAR can be used safely with a better oncological outcome than APR. due to the inherent limitations of the present study, for example, the trails available for this systematic review are limited and the finite retrospective data, future prospective randomized controlled trials will be useful to fully investigate these outcome measures and to confirm this conclusion.

Automatic detection of the existence of subarachnoid hemorrhage from clinical CT images.

Subarachnoid hemorrhage (SAH) is a medical emergency which can lead to death or severe disability. Misinterpretation of computed tomography (CT) in patients with SAH is a common problem. How to improve the accuracy of diagnosis is a great challenge to both the clinical physicians and medical researchers. In this paper we proposed a method for the automatic detection of SAH on clinical non-contrast head CT scans. The novelty includes approximation of the subarachnoid space in head CT using an atlas based registration, and exploration of support vector machine to the detection of SAH. The study included 60 patients with SAH and 69 normal controls from clinical hospitals. Thirty patients with SAH and 30 normal controls were used for training, while the rest were used for testing to achieve a testing sensitivity of 100% and specificity of 89.7%. The proposed algorithm might be a potential tool to screen the existence of SAH.