Impact of clay particle reattachment on suffusion of sand-clay mixtures

The detached clay particles directly filtrated through the sand-clay mixture lead to suffusion; however, if the detached clay particles are subjected to reattachment, the degree of suffusion may be less significant. This study investigates the impact of clay particle reattachment on suffusion of sand-clay mixtures through laboratory soil-column experiments. The observed breakthrough curves (BTCs) of kaolinite, illite, and montmorillonite for 5 different column lengths (3 in, 6 in, 9 in, 12 in, and 18 in; 1 in = 2.54 cm) indicated that a higher breakthrough concentration was observed as the column length (L) decreased for kaolinite and illite, whereas a reverse trend was observed for montmorillonite. In addition, the increase in the fraction of filtrated clay particles (Me) with an increase in L (Me = 10.42% for L = 3 in and Me = 3.59% for L = 18 in) for the sand-illite mixture indicated that the reattachment effect became more significant as the travel length of detached clay particles increased. The observed BTCs, retention profiles after injection, and fraction of filtrated clay presented herein suggest the need to incorporate the reattachment effect when assessing the suffusion of clay-containing soils

Tuning Polarity in Naphthalenediimide-Based Field-Effect Transistors through Incorporation of Alkoxy-Bithiophene Unit

The recent development of low-band-gap polymers comprising alternating donor and acceptor units in the backbone led to an improvement in the charge transport properties of organic field-effect transistors (OFETs). Among many conjugated semiconducting materials, P(NDI2OD-T2) (also known as Polyera ActivInk N2200) is well-known as a top-performing n-channel material comprising a naphthalenediimide acceptor and a bithiophene donor units. Herein, we report ambipolar OFETs based on (NDI2OD-T2) analogous polymers by introducing simultaneously the alkoxy-bithiophene unit and changing of alkyl branching point. This study advances our fundamental understanding of how polymer structure influences dominant polarity of charge carriers and reveals a new synthetic strategy for the design of ambipolar semiconducting materials

Should total omentectomy be performed for advanced gastric cancer?: The role of omentectomy during laparoscopic gastrectomy for advanced gastric cancer

© 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Background: In the era of minimally invasive surgery, laparoscopic partial omentectomy (LPO) has seen widespread use as a curative surgical procedure for early gastric cancer. However, scientific evidence of the extent of omentectomy during laparoscopic gastrectomy remains unclear for advanced gastric cancer (AGC). Methods: We analyzed 666 eligible patients who underwent laparoscopic gastrectomy for AGC with curative intent between 2014 and 2018. Surgical outcome and postoperative prognosis were compared between LPO and laparoscopic total omentectomy (LTO) groups after 2:1 propensity score matching with age, sex, body mass index, tumor size, pT stage, pN stage, gastrectomy type, and clinical T stage as covariates. Results: After extensive matching, there was no significant difference in pathologic or clinical stages between the LPO (n = 254) and LTO (n = 177) groups. LPO provided a significantly shorter operation time than LTO (199.2 ± 64.8 vs. 248.1 ± 68.3 min, P < 0.001). Pulmonary complication within postoperative 30 days was significantly lower in the LPO group (4.4 vs. 10.3%, P = 0.018). In multivariate analysis, LTO was the independent risk factor for pulmonary complication (odds ratio [OR] 2.53, 95% confidence interval [95% CI] 1.12–5.73, P = 0.025), which became more obvious in patients with a Charlson’s comorbidity index of 4 or higher (OR 27.43, 95% CI 1.35–558.34, P = 0.031). The 5-year overall survival rate (OS) and 3-year recurrence-free survival (RFS) rates were not significantly different between the two groups, even after stage stratification. Conclusion: LPO provided significantly shorter operation time and less pulmonary complication than LTO without compromising 5-year OS and 3-year RFS for AGC. LTO was the independent risk factor for pulmonary complications, which became more evident in patients with severe comorbidities.N

Controlled Insertion of Planar Defect in Inverse Opals for Anticounterfeiting Applications

Inverse opals have been used for structural coloration and photonic applications owing to their photonic bandgap properties. When the photonic structures contain planar defects, they provide defect modes, which are useful for lasing, sensing, and waveguiding. However, it remains a challenge to insert a planar defect into inverse opals in a reproducible manner. Here, we report a new method for producing planar-defect-inserted inverse opals using sequential capillary wetting of colloidal crystals and creating micropatterns through photolithography. Three cycles of deposition and thermal embedding of colloidal crystals into the underlying film of negative photoresist were performed. In the three cycles, opal, particle monolayer, and opal were sequentially employed, which yielded the monolayer-templated planar defect sandwiched by two inverse opals after particle removal. The planar defect provided a passband whose wavelength can be controlled by adjusting the diameter of particles for the defect layer. Moreover, the defect-inserted inverse opals can be micropatterned by photolithography as the negative photoresist is used as a matrix. The resulting micropatterns deliver a unique spectral code featured by a combination of stop band and defect mode and a graphical code dictated by photolithography, being useful for anticounterfeiting applications

Viable Mixing Protocol Based on Formulated Equations for Achieving Desired Molecular Weight and Maximal Charge Separation of Photovoltaic Polymer

A major difficulty in the polymer solar cell (PSC) community is discovering a methodology capable of accessing polymeric photovoltaic materials with controllable/predictable molecular weights. Effective mathematical equations that enable the reproduction of polymer batches with precisely controlled molecular weight, by mixing as-synthesized polymer batches with the ones that have different molecular weights, are formulated in this study. The properties of both the as-synthesized and mixed-different-molecular weight PM6 polymer series are systematically investigated to determine the effect of molecular weight on the performance of related PSCs. The power conversion efficiencies (PCEs) improve monotonically with an increase in weight average molecular weight (M-w) up to 120 kDa, but a further increase in M-w results in a sharp decline in PCE. This trend in PCEs is correlated with the charge-separation efficacy as a function of the balance between the counteracting domain size and packing in the blends. Further, decreasing the polydispersity index in the optimal-molecular weight PM6 sample produces a small but noticeable positive effect on device performance, yielding the best PCE of 16.5%. This viable mixing approach is useful in producing desirable molecular weight polymers, facilitating the development of high-quality, high-reproducibility photovoltaic polymers

Single-Incision Proximal Gastrectomy With Double-Flap Esophagogastrostomy Using Novel Laparoscopic Instruments

Background.The optimal type of anastomosis after proximal gastrectomy (PG) is still controversial. A novel technique termed "double-flap" esophagogastrostomy (EG) has been introduced. The application of this technique after PG is reported to have little gastroesophageal reflux without the need of creating an esophagojejunostomy. However, this procedure is technically challenging and hence difficult to apply in laparoscopic PG. This technical report describes in detail how to perform single-incision proximal gastrectomy (SIPG) with double-flap EG with the use of novel laparoscopic instruments.Methods.Two patients diagnosed with early gastric cancer underwent SIPG. A 2.5 cm incision was made, and a scope holder was used in place of a scopist. After performing PG with D1+ lymphadenectomy, double seromuscular flaps were created on the anterior wall of the stomach. After tagging the esophagus to the inferior edge of the flap window, the stomach and esophagus were opened through electrocautery. EG was performed intracorporeally using continuous barbed sutures, and the flap is then secured to the anastomosis. To facilitate this procedure, an intra-abdominal organ retractor and an articulating needle holder were used. The supplementary video illustrates in detail how these devices are used to perform the technique.Results.Total operation times were 190 and 110 minutes each, and anastomosis took 75 and 46 minutes each. Patients had no complications and were both discharged on postoperative day 6.Conclusion.Double-flap PG is technically feasible through a single incision with the use of articulating laparoscopic devices and intra-abdominal organ retractors to assist in intracorporeal anastomosis.N

Prognostic significance of surgery‐induced sarcopenia in the survival of gastric cancer patients: a sex‐specific analysis

Abstract Background Preoperative sarcopenia is associated with a poor long‐term prognosis in patients with gastric cancer (GC). Most GC patients rapidly lose muscle mass after gastrectomy. This retrospective cohort study analysed the effect of postoperative muscle loss and surgery‐induced sarcopenia on the long‐term outcomes of patients with GC. Methods Preoperative and postoperative 1 year abdominal computed tomography scans were available for 1801 GC patients who underwent curative gastrectomy between January 2009 and December 2013 at Seoul National University Bundang Hospital. The patients were categorized into normal, presarcopenia, and sarcopenia groups according to the skeletal muscle index (SMI) measured on computed tomography scans. Patients who were not sarcopenic prior to gastrectomy but became sarcopenic after surgery were defined as the surgery‐induced sarcopenia group. Results There were 1227 men and 574 women included in the study. The mean age of the patients was 59.5 ± 12.3 years. Multivariable Cox‐regression analyses showed that preoperative SMI was not associated with overall survival (OS). However, postoperative sarcopenia was associated with significantly worse OS only in men [hazard ratio (HR), 1.75; 95% confidence interval (CI), 1.08–2.85]. SMI loss was an independent risk factor for OS in the entire cohort and in men (HR, 1.01; 95% CI, 1.00–1.02, for the entire cohort; HR, 1.02; 95% CI, 1.01–1.04, for men). The surgery‐induced sarcopenia group was associated with significantly higher mortality (HR, 1.84; 95% CI, 1.16–2.90, for the cohort; HR, 2.73; 95% CI, 1.54–4.82, for men), although SMI loss and surgery‐induced sarcopenia were not risk factors in women. Similar results were obtained for relapse‐free survival. Conclusions Postoperative muscle mass loss and surgery‐induced sarcopenia are prognostic factors for survival in patients with GC. Impact of postoperative muscle mass loss and surgery‐induced sarcopenia on survival outcomes is dependent on the sex

A built-in electric field induced by ferroelectrics increases halogen-free organic solar cell efficiency in various device types

In principle, an electric field via ferroelectric materials can affect the photovoltaic properties, although there is not yet a complete mechanistic understanding. Herein, a built-in electric field without a poling processing step was established by introducing developed PVDF-based ferroelectric additives within active-layer matrices of organic solar cells (OSCs). Upon the existence of the ferroelectric polarization induced by the ferroelectric additives in o-xylene/N-methylpyrrolidone pair featuring halogen-free processing system, high efficiencies of 11.02% and 11.76% are achieved in fullerene and non-fullerene acceptor bulk-heterojunction OSCs, respectively. A comparative study exploring the role of the ferroelectric polarization surrounding the active-layer matrix was also performed using structural, electrical, and morphological techniques, to shed light on the underlying ferroelectric polarization effects on OSCs. Furthermore, the use of the ferroelectric additive is extended to p-n like bilayer OSC to access a rich understanding of the complex enhancement mechanisms afforded by it, demonstrating a highly efficient (11.83%) bilayer device. The above results are fairly comparable to the highest value reported for the recently developed state-of-the-art OSCs processed from halogen-free systems. The use of the ferroelectric additives in the halogen-free system is promising in related organic-semiconductor fields for reasons extending beyond the enhancement of efficiency and the environment-friendly manufacturing