Abstract
Ag(I) is commonly employed as an electron scavenger to promote water oxidation. In addition to its straightforward role as an electron acceptor, Ag(I) can also capture holes to generate the ...high-valent silver species. Herein, we demonstrate photoelectrocatalytic (PEC) water oxidation and concurrent dioxygen evolution by the silver redox cycle where Ag(I) acts as a hole-transfer mediator. Ag(I) enhances the PEC performance of WO
3
electrodes at 1.23 V vs. RHE with increasing O
2
evolution, while forming Ag(II) complexes (Ag
II
NO
3
+
). Upon turning off both light and potential bias, the photocurrent immediately drops to zero, whereas O
2
evolution continues over ~10 h with gradual bleaching of the colored complexes. This phenomenon is observed neither in the Ag(I)-free PEC reactions nor in the photocatalytic (i.e., bias-free) reactions with Ag(I). This study finds that the role of Ag(I) is not limited as an electron scavenger and calls for more thorough studies on the effect of Ag(I).
High efficiency solar photocatalysis requires an effective separation of photogenerated charge carriers and their rapid transport to the semiconductor interface. The mechanisms and kinetics of charge ...separation and interfacial/interparticle charge transfers (CT) are significantly influenced by both the bulk and surface properties of the semiconductor. The surface properties are particularly important because the photocatalysis should be driven by the interfacial CT. The most popular and the most investigated semiconductor photocatalyst is based on bare and modified TiO
2
. This article highlights the interfacial and interparticle CTs under the bandgap excitation of TiO
2
particles, visible light-induced photochemical processes
via
either dye-sensitization or ligand-to-metal CTs at surface modified TiO
2
particles, and the applications of the photo-processes to pollutant degradation and simultaneous hydrogen production. While a variety of surface modification techniques using various nanomaterials and chemical reagents have been developed and tested so far, their effects are very diverse depending on the characteristics of the applied photocatalytic systems and even contradictory in some cases. Better understanding of how the modification influences the photoinduced CT events in semiconductors is required, particularly for designing hybrid photocatalysts with controlled CTs, which is sought-after for practical applications of photocatalysis.
High efficiency solar photocatalysis requires an effective separation of photogenerated charge carriers and their rapid transport to the semiconductor interface.
This study elucidates the mechanism behind persulfate activation by exploring the role of various oxyanions (e.g., peroxymonosulfate, periodate, and peracetate) in two activation systems utilizing ...iron nanoparticle (nFe0) as the reducing agent and single-wall carbon nanotubes (CNTs) as electron transfer mediators. Since the tested oxyanions serve as both electron acceptors and radical precursors in most cases, oxidative degradation of organics was achievable through one-electron reduction of oxyanions on nFe0 (leading to radical-induced oxidation) and electron transfer mediation from organics to oxyanions on CNTs (leading to oxidative decomposition involving no radical formation). A distinction between degradative reaction mechanisms of the nFe0/oxyanion and CNT/oxyanion systems was made in terms of the oxyanion consumption efficacy, radical scavenging effect, and EPR spectral analysis. Statistical study of substrate-specificity and product distribution implied that the reaction route induced on nFe0 varies depending on the oxyanion (i.e., oxyanion-derived radical), whereas the similar reaction pathway initiates organic oxidation in the CNT/oxyanion system irrespective of the oxyanion type. Chronoamperometric measurements further confirmed electron transfer from organics to oxyanions in the presence of CNTs, which was not observed when applying nFe0 instead.
This study introduces graphited nanodiamond (G-ND) as an environmentally friendly, easy-to-regenerate, and cost-effective alternative catalyst to activate persulfate (i.e., peroxymonosulfate (PMS) ...and peroxydisulfate (PDS)) and oxidize organic compounds in water. The G-ND was found to be superior for persulfate activation to other benchmark carbon materials such as graphite, graphene, fullerene, and carbon nanotubes. The G-ND/persulfate showed selective reactivity toward phenolic compounds and some pharmaceuticals, and the degradation kinetics were not inhibited by the presence of oxidant scavengers and natural organic matter. These results indicate that radical intermediates such as sulfate radical anion and hydroxyl radical are not majorly responsible for this persulfate-driven oxidation of organic compounds. The findings from linear sweep voltammetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and electron paramagnetic resonance spectroscopy analyses suggest that the both persulfate and phenol effectively bind to G-ND surface and are likely to form charge transfer complex, in which G-ND plays a critical role in mediating facile electron transfer from phenol to persulfate.
Background
Previous studies evaluating the prognostic value of computed tomography (CT)‐derived body composition data have included few patients. Thus, we assessed the prevalence and prognostic value ...of sarcopenic obesity in a large population of gastric cancer patients using preoperative CT, as nutritional status is a predictor of long‐term survival after gastric cancer surgery.
Methods
Preoperative CT images were analyzed for 840 gastric cancer patients who underwent gastrectomy between March 2009 and June 2018. Machine learning algorithms were used to automatically detect the third lumbar (L3) vertebral level and segment the body composition. Visceral fat area and skeletal muscle index at L3 were determined and used to classify patients into obesity, sarcopenia, or sarcopenic obesity groups.
Results
Out of 840 patients (mean age = 60.4 years; 526 62.6% men), 534 (63.5%) had visceral obesity, 119 (14.2%) had sarcopenia, and 48 (5.7%) patients had sarcopenic obesity. Patients with sarcopenic obesity had a poorer prognosis than those without sarcopenia (hazard ratio HR = 3.325; 95% confidence interval CI = 1.698–6.508). Multivariate analysis identified sarcopenic obesity as an independent risk factor for increased mortality (HR = 2.608; 95% CI = 1.313–5.179). Other risk factors were greater extent of gastrectomy (HR = 1.928; 95% CI = 1.260–2.950), lower prognostic nutritional index (HR = 0.934; 95% CI = 0.901–0.969), higher neutrophil count (HR = 1.101; 95% CI = 1.031–1.176), lymph node metastasis (HR = 6.291; 95% CI = 3.498–11.314), and R1/2 resection (HR = 4.817; 95% CI = 1.518–9.179).
Conclusion
Body composition analysis automated by machine learning predicted long‐term survival in patients with gastric cancer.
It is unclear whether laparoscopic distal gastrectomy for locally advanced gastric cancer is oncologically equivalent to open distal gastrectomy. The noninferiority of laparoscopic subtotal ...gastrectomy with D2 lymphadenectomy for locally advanced gastric cancer compared with open surgery in terms of 3-year relapse-free survival rate was evaluated.
A phase III, open-label, randomized controlled trial was conducted for patients with histologically proven locally advanced gastric adenocarcinoma suitable for distal subtotal gastrectomy. The primary end point was the 3-year relapse-free survival rate; the upper limit of the hazard ratio (HR) for noninferiority was 1.43 between the laparoscopic and open distal gastrectomy groups.
From November 2011 to April 2015, 1,050 patients were randomly assigned to laparoscopy (n = 524) or open surgery (n = 526). After exclusions, 492 patients underwent laparoscopic surgery and 482 underwent open surgery and were included in the analysis. The laparoscopy group, compared with the open surgery group, suffered fewer early complications (15.7%
23.4%, respectively;
= .0027) and late complications (4.7%
9.5%, respectively;
= .0038), particularly intestinal obstruction (2.0%
4.4%, respectively;
= .0447). The 3-year relapse-free survival rate was 80.3% (95% CI, 76.0% to 85.0%) for the laparoscopy group and 81.3% (95% CI, 77.0% to 85.0%; log-rank
= .726) for the open group. Cox regression analysis after stratification by the surgeon revealed an HR of 1.035 (95% CI, 0.762 to 1.406; log-rank
= .827;
for noninferiority = .039). When stratified by pathologic stage, the HR was 1.020 (95% CI, 0.751 to 1.385; log-rank
= .900;
for noninferiority = .030).
Laparoscopic distal gastrectomy with D2 lymphadenectomy was comparable to open surgery in terms of relapse-free survival for patients with locally advanced gastric cancer. Laparoscopic distal gastrectomy with D2 lymphadenectomy could be a potential standard treatment option for locally advanced gastric cancer.
IMPORTANCE: Fluorescent imaging with indocyanine green can be used to visualize lymphatics. Peritumoral injection of indocyanine green may allow for visualization of every draining lymph node from a ...primary lesion on near-infrared imaging. OBJECTIVES: To evaluate the role of fluorescent lymphography using near-infrared imaging as an intraoperative tool for achieving complete lymph node dissection and compare the number of lymph nodes retrieved with the use of near-infrared imaging and the number of lymph nodes retrieved without the use of near-infrared imaging. DESIGN, SETTING, AND PARTICIPANTS: This prospective single-arm study was conducted among 40 patients who underwent robotic gastrectomy between August 30, 2013, and July 21, 2014, at a single-center, tertiary referral teaching hospital. After propensity score matching, the results of these 40 patients were compared with the results of 40 historical control patients who underwent robotic gastrectomy without indocyanine green injection between January 1, 2012, and August 31, 2013. Statistical analysis was performed from January 1, 2015, to July 31, 2016. INTERVENTIONS: Robotic gastrectomy with systemic lymphadenectomy and retrieval of lymph nodes under near-infrared imaging after peritumoral injection of indocyanine green to the submucosal layer 1 day before surgery. MAIN OUTCOMES AND MEASURES: The primary outcome was the number of retrieved lymph nodes in each nodal station. RESULTS: Among the 40 patients in the study (19 women and 21 men; mean SD age, 52.2 11.7 years), no complications related to indocyanine green injection or near-infrared imaging were observed. On completion of the lymphadenectomy, the absence of fluorescent lymph nodes in the dissected area was confirmed. A mean (SD) total of 23.9 (9.0) fluorescent lymph nodes were recorded among a mean (SD) total of 48.9 (14.6) overall lymph nodes retrieved. The mean number of overall lymph nodes retrieved was larger in the near-infrared group than in the historical controls (48.9 vs 35.2; P < .001), with a significantly greater number of lymph nodes retrieved at stations 2, 6, 7, 8, and 9. In the near-infrared group, 5 patients exhibited lymph node metastases, and all metastatic lymph nodes were fluorescent. CONCLUSIONS AND RELEVANCE: This study’s findings suggest that fluorescent lymphography may be useful intraoperatively for identifying and retrieving all necessary lymph nodes for a complete and thorough lymphadenectomy.
Proper co-catalysts (usually noble metals), combined with semiconductor materials, are commonly needed to maximize the efficiency of photocatalysis. Search for cost-effective and practical ...alternatives for noble-metal co-catalysts is under intense investigation. In this work, nanodiamond (ND), which is a carbon nanomaterial with a unique sp3(core)/sp2(shell) structure, was combined with WO3 (as an alternative co-catalyst for Pt) and applied for the degradation of volatile organic compounds under visible light. NDs-loaded WO3 showed a highly enhanced photocatalytic activity for the degradation of acetaldehyde (∼17 times higher than bare WO3), which is more efficient than other well-known co-catalysts (Ag, Pd, Au, and CuO) loaded onto WO3 and comparable to Pt-loaded WO3. Various surface modifications of ND and photoelectochemical measurements revealed that the graphitic carbon shell (sp2) on the diamond core (sp3) plays a crucial role in charge separation and the subsequent interfacial charge transfer. As a result, ND/WO3 showed much higher production of OH radicals than bare WO3 under visible light. Since ND has a highly transparent characteristic, the light shielding that is often problematic with other carbon-based co-catalysts was considerably lower with NDs-loaded WO3. As a result, the photocatalytic activity of NDs/WO3 was higher than that of WO3 loaded with other carbon-based co-catalysts (graphene oxide or reduced graphene oxide). A range of spectroscopic and photo(electro)chemical techniques were systematically employed to investigate the properties of NDs-loaded WO3. ND is proposed as a cost-effective and practical nanomaterial to replace expensive noble-metal co-catalysts.
Background
With improved short-term surgical outcomes, laparoscopic distal gastrectomy has rapidly gained popularity. However, the safety and feasibility of laparoscopic total gastrectomy (LTG) has ...not yet been proven due to the difficulty of the technique. This single-arm prospective multi-center study was conducted to evaluate the use of LTG for clinical stage I gastric cancer.
Methods
Between October 2012 and January 2014, 170 patients with pathologically proven, clinical stage I gastric adenocarcinoma located at the proximal stomach were enrolled. Twenty-two experienced surgeons from 19 institutions participated in this clinical trial. The primary end point was the incidence of postoperative morbidity and mortality at postoperative 30 days. The severity of postoperative complications was categorized according to Clavien–Dindo classification, and the incidence of postoperative morbidity and mortality was compared with that in a historical control.
Results
Of the enrolled patients, 160 met criteria for inclusion in the full analysis set. Postoperative morbidity and mortality rates reached 20.6% (33/160) and 0.6% (1/160), respectively. Fifteen patients (9.4%) had grade III or higher complications, and three reoperations (1.9%) were performed. The incidence of morbidity after LTG in this trial did not significantly differ from that reported in a previous study for open total gastrectomy (18%).
Conclusions
LTG performed by experienced surgeons showed acceptable postoperative morbidity and mortality for patients with clinical stage I gastric cancer.
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