Post-treatment Strategy Research Articles

An efficient post-treatment strategy with acetylacetone for low temperature CsPbI2Br solar cells

All inorganic perovskite solar cells (PSCs) have been demonstrated to get tremendous interest recently owing to their better thermal stability. Nevertheless, some CsPbI2Br films prepared at low temperature have lower quality compared to those annealing at high temperature. Herein, to obtain high performance PSCs, a simple post-treatment strategy is presented by spin coating acetylacetone (AA) solution on the CsPbI2Br films. The AA treatment can reduce the density traps on the CsPbI2Br films surface and enlarge the size of grains, resulting in enhanced performance PSCs. After optimizing surface treatment, the devices based on low-temperature-processed CsPbI2Br with AA treatment achieved a power conversion efficiency (PCE) of 14.43%. The better CsPbI2Br films quality and interface contact of hole transport layer (HTL)/CsPbI2Br result in better device stability. Therefore, it could be a promising post treatment method for enhancing the performance of PSCs by introducing AA on the perovskite surface.

Enhanced porosity of Ni@Hollow meso-SiO2 catalyst for CO2 reforming of methane

The dry reforming of methane is a potential reaction that converts methane and carbon dioxide to syngas while mitigating the two greenhouse gases. Challenges for this reaction include sintering and severe carbon deposition. This paper reports a post-treatment strategy to develop Ni@hollow meso-SiO2 (Ni@HMS) catalyst from the existing Ni@SiO2 core-shell structure by utilizing the mechanism of etching and re-deposition of silica in mild alkaline solution with CTAB as a stabilizer. The varied post-treatment temperature changed the properties of Ni@HMS and demonstrated high catalytic performance compared to Ni@SiO2. The results from TEM and XPS showed the Ni particles were confined inside the mesoporous SiO2 shell and inhibit Ni particle mobility. The catalysts exhibited high conversion of methane (>80%) and carbon dioxide (>90%) for 50 h at 800 °C and WHSV of 54 000 mL gcat−1h−1 with high TOFCH4 of 7.08 s−1.

Synergistic Interface Layer Optimization and Surface Passivation with Fluorocarbon Molecules toward Efficient and Stable Inverted Planar Perovskite Solar Cells.

Large-size organic halide passivation has been considered an efficient approach to enhance the perovskite solar cell (PSC) efficiency and stability. Herein, a facile posttreatment strategy was demonstrated, wherein trifluoromethyl-phenethylamine hydrobromide (CF3-PEABr) is firstly used to passivate the perovskite film surface. The CF3-PEABr surface posttreatment could coordinate with halide dangling bonds that exist at the perovskite crystal surface. Moreover, the surface treatment with CF3-PEABr could efficiently passivate the defects in the perovskite film and suppress the nonradiative carrier recombination. As a result, a high efficiency of 21.3% is obtained, and an increment of 80 mV in Voc (a large Voc of 1.15 V, with a 0.42 V voltage deficit) occurs, compared to the control device. To relieve the hydrophobic nature properties of the -CF3 functional group and the dewetting problem of PCBM layer deposition, a surfactant Triton X-100 is used to modify the PCBM layer. Furthermore, the devices with CF3-PEABr posttreatment exhibit better operational, thermal (85°C), and long storage stabilities without any encapsulation.

Stable and high performance all-inorganic perovskite light-emitting diodes with anti-solvent treatment

Optoelectronic applications based on the perovskites always face challenges due to the inherent chemical composition volatility of perovskite precursors. The efficiency of perovskite-based light-emitting diodes (Pe-LEDs) can be enhanced by improving the perovskite film via solvent engineering. A dual solvent post-treatment strategy was applied to the perovskite film, which provides a synchronous effect of passivating surface imperfections and reduces exciton quenching, as evidenced by improved surface morphology and photoluminance. Thus, the optimized Pe-LEDs reach 17,866 cd·m−2 maximum brightness, 45.8 cd·A−1 current efficiency, 8.3% external quantum efficiency, and relatively low turn-on voltage of 2.0 V. Herein, we present a simple technique for the fabrication of stable and efficient Pe-LEDs.

Cost-Effective Production of TiO2 with 90-Fold Enhanced Photocatalytic Activity Via Facile Sequential Calcination and Ball Milling Post-Treatment Strategy.

Titanium dioxide (TiO2), the golden standard among the photocatalysts, exhibits a varying level of photocatalytic activities (PCA) amongst the synthetically prepared and commercially available products. For commercial applications, superior photoactivity and cost-effectiveness are the two main factors to be reckoned with. This study presents the development of simple, cost-effective post-treatment processes for a less costly TiO2 to significantly enhance the PCA to the level of expensive commercial TiO2 having demonstrated superior photoactivities. We have utilized sequential calcination and ball milling (BM) post-treatment processes on a less-costlier KA100 TiO2 and demonstrated multi-fold (nearly 90 times) enhancement in PCA. The post-treated KA100 samples along with reference commercial samples (P25, NP400, and ST01) were well-characterized by appropriate instrumentation and evaluated for the PCA considering acetaldehyde photodegradation as the model reaction. Lattice parameters, phase composition, crystallite size, surface functionalities, titanium, and oxygen electronic environments were evaluated. Among post-treated KA100, the sample that is subjected to sequential 700 °C calcination and BM (KA7-BM) processes exhibited 90-fold PCA enhancement over pristine KA100 and the PCA-like commercial NP400 (pure anatase-based TiO2). Based on our results, we attribute the superior PCA for KA7-BM due to the smaller crystallite size, the co-existence of mixed anatase-srilankite-rutile phases, and the consequent multiphase heterojunction formation, higher surface area, lattice disorder/strain generation, and surface oxygen environment. The present work demonstrates a feasible potential for the developed post-treatment strategy towards commercial prospects.

Effects of annealing process on thermoelectric performance for Pb-doped BiCuSeO

In this work, we investigated the effects of annealing process on thermoelectric performance for Pb0.06Bi0.94Cu0.94SeO sample. Under the appropriate annealing time of 573 K, the electrical conductivity was significantly improved on the premises of a higher carrier concentration. As a result, a high power factor of 1096 µWm−1 K−2 was achieved at 323 K. Furthermore, the lattice thermal conductivity obviously decreased as the annealing time rose up to 3 days, which mostly benefited from the stronger phonon scattering and the precipitation of the second phase. Consequently, for the Pb0.06Bi0.94Cu0.94SeO sample annealed for 1 day, a maximum ZT value of 0.85 was obtained at 873 K, which was 57% and 12% higher than those of pristine BiCuSeO and un-annealed sample, respectively. This work proposes an effective post-treatment strategy to enhance the thermoelectric properties of BiCuSeO-based compounds.

Molecular changes associated with the anticancer effect of sulforaphane against Ehrlich solid tumour in mice.

The anticancer effect of sulforaphane (SFN) is mediated by several signalling pathways. However, little is known regarding the underlying mechanism in Ehrlich solid tumours (ESTs) in mice. This study was conducted to determine molecular changes associated with the anticancer effect of SFN and to compare its preventive (cotreatment) and therapeutic (posttreatment) effects. Ehrlich (murine mammary adenocarcinoma) solid tumour was selected and changes in the gene expression were determined in tumour tissues by the real-time polymerase chain reaction. The results showed that SFN increased the expression of the oxidative stress gene NrF2 and its downstream targets (HO1 and CAT). Conversely, SFN administration decreased the expression of the epigenesis-related genes (HDAC1 and DNMT1)and inflammation-related genes (TNFa, NFkB and Cox2). Overall, SFN cotreatment presented notable molecular changes than the posttreatment strategy. These data suggest that molecular changes associated with the anticancer effects of SFN against EST involved induction of oxidative stress, inhibition of inflammationand epigenetic modifications.

Long-Term Clinical Outcome and Prognosis After Thrombectomy in Patients With Concomitant Malignancy.

Endovascular thrombectomy (EVT) is the preferred treatment strategy for patients with acute ischemic stroke (AIS). However, clinical outcome and prognosis in patients who undergo EVT in response to AIS with concomitant malignancy have not been fully elucidated. Data of patients with malignancy who underwent EVT at participating institutions between January 2015 and April 2019 were retrospectively analyzed. Patient characteristics, treatment methods, posttreatment strategy, and long-term prognosis were evaluated in 12 patients with prediagnoses of malignancy. Good revascularization (TICI 2b or higher) was achieved in 10 of 12 patients. Among the eight patients who survived more than 2 weeks from onset, four patients showed good clinical outcome [modified Rankin Scale (mRS) <2] at 60 days posttreatment and were able to continue treatment for malignancy. However, seven of eight patients died within a year of EVT (median survival, 83 days) due to progression of malignancy. One-year survival was achieved in only one patient whose etiology of stroke was determined as infectious endocarditis and not Trousseau syndrome. Even after successful revascularization and good short-term clinical outcome, the long-term prognosis after thrombectomy in patients with malignancy was poor. Thrombectomy for concomitant malignancy requires judicious decision, and further studies are necessary to fully elucidate its efficacy.

An optimal posttreatment surveillance strategy for cancer survivors based on an individualized risk-based approach

The optimal post-treatment surveillance strategy that can detect early recurrence of a cancer within limited visits remains unexplored. Here we adopt nasopharyngeal carcinoma as the study model to establish an approach to surveillance that balances the effectiveness of disease detection versus costs. A total of 7,043 newly-diagnosed patients are grouped according to a clinic-molecular risk grouping system. We use a random survival forest model to simulate the monthly probability of disease recurrence, and thereby establish risk-based surveillance arrangements that can maximize the efficacy of recurrence detection per visit. Markov decision-analytic models further validate that the risk-based surveillance outperforms the control strategies and is the most cost-effective. These results are confirmed in an external validation cohort. Finally, we recommend the risk-based surveillance arrangement which requires 10, 11, 13 and 14 visits for group I to IV. Our surveillance strategies might pave the way for individualized and economic surveillance for cancer survivors.

Electrostatic Self-assembly Aided Synthesis of CdS/Cs3PW12O40 Hybrids for Photocatalytic Reduction of Cr(VI)

Photocatalytic reduction is a promising approach to detoxifying carcinogenic Cr(VI) in water. Herein, CdS-sensitized Cs3PW12O40 composites were fabricated by electrostatic self-assembly followed by hydrothermal post-treatment strategy. The composite with 28.6 wt% CdS loading (CdS/CsPW) was characterized by XRD, FT-IR, SEM/TEM, EDX, UV-vis DRS, XPS, potentiometric titration, and N2 adsorption. The catalytic activity was evaluated by reducing Cr(VI) in the presence of EDTA under UV and visible light irradiation. The results revealed that CdS/CsPW had good photocatalytic reduction performance for Cr(VI) degradation under both UV and visible light illumination. After four-time repetitive use, ~ 93% of catalytic activity still remained. The photocatalytic reduction of Cr(VI) under visible light irradiation followed pseudo-first-order kinetics; the decreasing solution pH and initial Cr(VI) concentration, and increasing catalyst dosage and EDTA concentration were beneficial to Cr(VI) photoreduction. XPS analyses further indicated that the Cr(VI) adsorbed on surface of the catalyst was also reduced to Cr(III), and CdS and Cs3PW12O40 existed strong interaction. Meanwhile, the photoelectrons in CdS could migrate to Cs3PW12O40. Further, PL results verified CdS/CsPW heterostructure effectively suppressed the photogenerated electron-hole recombination. Based on experimental results, the mechanisms for Cr(VI) photoreduction by the prepared catalyst were proposed. This work may provide an attractive avenue to construct the efficient photocatalyst using polyoxometalates for environmental remediation.

Insight into the Selection of the Post-Treatment Strategy for ZSM-5 Zeolites for the Improvement of Catalytic Stability in the Conversion of Methanol to Hydrocarbons

Desilication and dealumination are two common strategies to modify acidity and porosity of the ZSM-5 catalyst to enhance catalytic stability. However, the applicability of these strategies on the p...

In-situ re-melting and re-solidification treatment of selective laser sintered polycaprolactone lattice scaffolds for improved filament quality and mechanical properties

Selective laser sintering (SLS) is a promising additive manufacturing technique that produces biodegradable tissue-engineered scaffolds with highly porous architectures without additional supporting. However, SLS process inherently results in partially melted microstructures which significantly impair the mechanical properties of the resultant scaffolds for potential applications in tissue engineering and regenerative medicine. Here, a novel post-treatment strategy was developed to endow the SLS-fabricated polycaprolactone (PCL) scaffolds with dense morphology and enhanced mechanical properties by embedding them in dense NaCl microparticles for in-situ re-melting and re-solidification. The effects of re-melting temperature and dwelling time on the microstructures of the SLS-fabricated filaments were studied. The results demonstrated that the minimum requirements of re-melting temperature and dwelling time for sufficient treatment were 65 °C and 5 min respectively and the size of the SLS-fabricated filaments was reduced from 683.3 ± 28.0 μm to 601.6 ± 17.4 μm. This method was also highly effective in treating three-dimensional (3D) PCL lattice scaffolds, which showed improved filament quality and mechanical properties after post-treatment. The treated PCL scaffolds with an initial compressive modulus and strength of 3027.8 ± 204.2 kPa and 208.8 ± 14.5 kPa can maintain their original shapes after implantation in vivo for 24 weeks. Extensive newly-grown tissues were found to gradually penetrate into the porous regions along the PCL filaments. Although degradation occurred, the mechanical properties of the implanted constructs stably maintained. The presented method provides an innovative, green and general post-treatment strategy to improve both the filament quality and mechanical properties of SLS-fabricated PCL scaffolds for various tissue engineering applications.

Hydrothermal Effect on Mechanical Properties of Nephila pilipes Spidroin.

The superlative mechanical properties of spider silk and its conspicuous variations have instigated significant interest over the past few years. However, current attempts to synthetically spin spider silk fibers often yield an inferior physical performance, owing to the improper molecular interactions of silk proteins. Considering this, herein, a post-treatment process to reorganize molecular structures and improve the physical strength of spider silk is reported. The major ampullate dragline silk from Nephila pilipes with a high β-sheet content and an adequate tensile strength was utilized as the study material, while that from Cyrtophora moluccensis was regarded as a reference. Our results indicated that the hydrothermal post-treatment (50–70 °C) of natural spider silk could effectively induce the alternation of secondary structures (random coil to β-sheet) and increase the overall tensile strength of the silk. Such advantageous post-treatment strategy when applied to regenerated spider silk also leads to an increment in the strength by ~2.5–3.0 folds, recapitulating ~90% of the strength of native spider silk. Overall, this study provides a facile and effective post-spinning means for enhancing the molecular structures and mechanical properties of as-spun silk threads, both natural and regenerated.

Green tea ameliorates the side effects of the silver nanoparticles treatment of Ehrlich ascites tumor in mice

Silver nanoparticles (AgNPs) have anti-cancer effects with fewer side effects than standard chemotherapeutic agents, however, they exert oxidative stress-based adverse effects on normal cells and so their applications have raised concern about possible health and environmental risks. We evaluated whether green tea extract (GTE), which contains potent antioxidants, could ameliorate AgNPs geno-, cyto-, and histotoxicities without decreasing their therapeutic potential against Ehrlich ascetic carcinoma (EAC). GTE enhanced the anti-cancer effect of AgNPs against EAC cells and ameliorated the genotoxic effect of AgNPs as indicated by lowering chromosomal aberrations and micronucleus frequencies. Additionally, GTE relieved most of degenerative histological changes induced by AgNPs. GTE restored the increased MDA and the decreased SOD, GPx and CAT serum levels induced by AgNPs to levels comparable to normal. The pre-treatment with GTE and AgNPs showed better improvement than the post-treatment strategy. GTE can not only ameliorate AgNPs-induced adverse effects but also improve their anti-cancer effect against EAC. So, it could be useful in the treatment of liver dysfunction associated with AgNPs.

In vitro and in silico anti-dengue activity of compounds obtained from Psidium guajava through bioprospecting

BackgroundFor decades, bioprospecting has proven to be useful for the identification of compounds with pharmacological potential. Considering the great diversity of Colombian plants and the serious worldwide public health problem of dengue—a disease caused by the dengue virus (DENV)—in the present study, we evaluated the anti-DENV effects of 12 ethanolic extracts derived from plants collected in the Colombian Caribbean coast, and 5 fractions and 5 compounds derived from Psidium guajava.MethodsThe cytotoxicity and antiviral effect of 12 ethanolic extracts derived from plants collected in the Colombian Caribbean coast was evaluated in epithelial VERO cells. Five fractions were obtained by open column chromatography from the ethanolic extract with the highest selectivity index (SI) (derived from P. guajava, SI: 128.2). From the fraction with the highest selectivity (Pg-YP-I-22C, SI: 35.5), five compounds were identified by one- and two-dimensional nuclear magnetic resonance spectroscopy. The antiviral effect in vitro of the fractions and compounds was evaluated by different experimental strategies (Pre- and post-treatment) using non-toxic concentrations calculated by MTT method. The DENV inhibition was evaluated by plate focus assay. The results were analyzed by means of statistical analysis using Student’s t-test. Finally the antiviral effect in Silico was evaluated by molecular docking.ResultsIn vitro evaluation of these compounds showed that three of them (gallic acid, quercetin, and catechin) were promising antivirals as they inhibit the production of infectious viral particles via different experimental strategies, with the best antiviral being catechin (100% inhibition with a pre-treatment strategy and 91.8% with a post-treatment strategy). When testing the interactions of these compounds with the viral envelope protein in silico by docking, only naringin and hesperidin had better scores than the theoretical threshold of − 7.0 kcal/mol (− 8.0 kcal/mol and − 8.2 kcal/mol, respectively). All ligands tested except gallic acid showed higher affinity to the NS5 protein than the theoretical threshold.ConclusionEven though bioprospecting has recently been replaced by more targeted tools for identifying compounds with pharmacological potential, our results show it is still useful for this purpose. Additionally, combining in vitro and in silico evaluations allowed us to identify promising antivirals as well as their possible mechanisms of action.

Post-treatment of Perovskite Films toward Efficient Solar Cells via Mixed Solvent Annealing

Post-treatment of perovskite films plays a crucial role in obtaining high-performance perovskite solar cells (PSCs). Solvent annealing (SA), as a universal post-treatment strategy, is profoundly be...

“Click” on SAP: Superabsorbent polymer surface modification via CuAAC reaction toward antibacterial activity and improved swollen gel strength

Superabsorbent polymer (SAP) hydrogel was synthesized and surface-modified by a “click” reaction approach to enhance the mechanical and antibacterial properties of the gel. Thus, a two-step post-treatment strategy was tuned based on solvent-induced volume phase transition and Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The processes and products were investigated by ATR-FTIR, oscillatory rheometry, SEM-EDX, XPS as well as swelling capacity and antibacterial activities. The 1,2,3-triazole formation was confirmed spectrally. The swollen gel storage modulus was significantly improved. The Cu-extracted modified SAPs represented the antibacterial activity against S. aureus and E. coli. This process is an advanced promising approach to improve and tune the properties of the microgels especially for biomedical applications.

Qualitative and Quantitative Analysis of Posttreatment Strategy After Endoscopic Resection for Patients with T1 Colorectal Cancer at High Risk of Lymph Node Metastasis.

Although endoscopic resection is increasingly performed to treat submucosal invasive colorectal cancer (T1CRC), approximately 10% are at risk of lymph node metastasis. The Japanese Society for Cancer of the Colon and Rectum guideline indicates that the following risk factors should be considered when deciding whether to perform additional surgical resection with lymph node dissection: depth of T1 invasion, lymphovascular invasion, poor histological grade, and budding grade 2/3. However, there is little information about the prognosis of T1CRC patients, or factors to consider when deciding subsequent treatment of high-risk T1CRC. This retrospective mixed method study was conducted using electronic medical records at Kyoto University Hospital between February 2005 and February 2015. Participants were T1CRC patients at risk of lymph node metastasis with at least one of the above four risk factors. They were assigned either careful follow-up (FU) or additional surgery (AS) through shared decision-making. To identify factors affecting decision-making in the FU group, we performed qualitative content analysis of electronic medical records. The prognosis of the groups was compared using the Kaplan-Meier method and the log-rank test. Of 161 T1CRC patients, 18 were included in the FU group and 19 in the AS group. The median follow-up time was 39.5 (range 23-126)months for the FU group and 62 (range 22-141)months for the AS group. Factors considered in selecting FU were advanced age, comorbidities, the sole presence of the "depth" risk factor, and lower rectal cancer. For AS, the risk factors cited in the guideline were considered. There was one recurrent case in each group during the research period. There were no significant differences in overall survival, cause-specific survival, or recurrence-free survival between the groups. Age, comorbidities, and lower-rectal cancer location were considered in deciding posttreatment strategy among high-risk T1CRC patients, alongside with positive vertical margin, depth, lymphovascular invasion, poor histologic grade, and budding. During the research period, there was no prognostic difference between the FU and AS groups.

Post-treatment of Fungal Biomass to Enhance Pigment Production

A new post-treatment method of fungal biomass after fermentation is revealed. The post-treatment strategy was utilized to produce pigments as an additional valuable metabolite. Post-treatment included incubation at 95% relative humidity where the effects of harvesting time, light, and temperature were studied. Pigment-producing edible filamentous fungus Neurospora intermedia cultivated on ethanol plant residuals produced 4 g/L ethanol and 5 g/L fungal biomass. Harvesting the pale biomass after 48 h submerged cultivation compared to 24 h or 72 h increased pigmentation in the post-treatment step with 35% and 48%, respectively. The highest pigment content produced, 1.4 mg/g dry fungal biomass, was obtained from washed biomass treated in light at 35 °C whereof the major impact on pigmentation was from washed biomass. Moreover, post-treated biomass contained 50% (w/w) crude protein. The post-treatment strategy successfully adds pigments to pre-obtained biomass. The pigmented fungal biomass can be considered for animal feed applications for domestic animals.

Whole body periodic acceleration improves survival and microvascular leak in a murine endotoxin model.

Sepsis is a life threatening condition which produces multi-organ dysfunction with profound circulatory and cellular derangements. Administration of E.Coli endotoxin (LPS) produces systemic inflammatory effects of sepsis including disruption of endothelial barrier, and if severe enough death. Whole body periodic acceleration (pGz) is the headward-footward motion of the body. pGz has been shown to induce pulsatile shear stress to the endothelium, thereby releasing vascular and cardio protective mediators. The purpose of this study was to determine whether or not pGz performed as a pre-treatment or post-treatment strategy improves survival in a lethal murine endotoxin model.This study was designed as a prospective randomized controlled study in mice. pGz was performed in mice as pre-treatment (pGz-LPS, 3 days prior to LPS), post-treatment (LPS- pGz, 30 min after LPS) strategies or Control (LPS-CONT), in a lethal murine model of endotoxemia. Endotoxemia was induced with intraperitoneal injection of E.Coli LPS (40mg/kg). In a separate group of mice, a nonspecific nitric oxide synthase inhibitor (L-NAME) was provided in their drinking water and pGz-LPS and LPS-pGz performed to determine the effect of nitric oxide (NO) inhibition on survival. In another subset of mice, micro vascular leakage was determined. Behavioral scoring around the clock was performed in all mice at 30 min intervals after LPS administration, until 48 hrs. survival or death. LPS induced 100% mortality in LPS-CONT animals by 30 hrs. In contrast, survival to 48 hrs. occurred in 60% of pGz-LPS and 80% of LPS-pGz. L-NAME abolished the survival effects of pGz. Microvascular leakage was markedly reduced in both pre and post pGz treated animals and was associated with increased tyrosine kinase endothelial-enriched tunica interna endothelial cell kinase 2 (TIE2) receptor and its phosphorylation (p-TIE2). In a murine model of lethal endotoxemia, pGz performed as a pre or post treatment strategy significantly improved survival, and markedly reduced microvascular leakage. The effect was modulated, in part, by NO since a non-selective inhibitor of NO abolished the pGz survival effect.