Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

A model for understanding electromigration-induced void evolution in dual-inlaid Cu interconnect structures

Electromigration-induced void evolution in various dual-inlaid copper (Cu) interconnect structures was simulated by applying a phenomenological model assisted by Monte Carlo-based simulations, considering the redistribution of heterogeneously nucleated voids and/or pre-existing vacancy clusters at the Cu/dielectric cap interface during electromigration. The results indicate that this model can qualitatively explain the electromigration-induced void evolution observed during experimental in situ secondary-electron microscopy (SEM) investigations as well as in various other reported studies. The electromigration mechanism in Cu interconnect structures and differences in the peculiar electromigration-induced void evolution in various dual-inlaid Cu interconnect structures can be clearly understood based on this model. These findings warrant reinvestigation of technologically important electromigration mechanisms by developing rigorous models based on similar concepts

Current crowding effect on copper dual damascene via bottom failure for ULSI applications

Reliability of interconnect via is increasing an important issue in submicron technology. Electromigration experiments are performed on line/via structures in two level Cu dual damascene interconnection system and it is found that wide line/via fails earlier than the narrow line/via. Atomic flux divergence based finite element analyses is performed and stress-migration is found to be important in the failure rate behavior observed. Semi-classical width dependence Black’s equation together with the finite element analysis revealed that the difference in the time to failure is due to the much larger average current density along the interface between the line and via for the wide line/via structure, and good agreement is obtained between the simulation and experimental results.Published versio

Simultaneous quantitative monitoring of four indicator contaminants of emerging concern (CEC) in different water sources of Central India using SPE/LC-(ESI)MS-MS

Environmental occurrence of CECs poses a great threat to both aquatic life and human health. The aim of this study was to optimize and validate SPE/ LC-(ESI)MS-MS method for simultaneous quantitative monitoring of two sub-classes of CECs (pharmaceuticals and hormones) and to estimate the concentrations of select CECs in environmental water samples. For all the tested analytes, recoveries in laboratory reagent water were greater than 81%. Average percent (relative standard deviation) RSD of the analytes in recovery, repeatability, and reproducibility experiments were ≤ 10%. Determination coefficients (r2) of primidone, diclofenac, testosterone, and progesterone were estimated to be 0.9979, 0.9972, 0.9968, and 0.9962, respectively. Limits of detection (LOD) for primidone, diclofenac, testosterone, and progesterone were 4.63 ng/L, 5.36 ng/L, 0.55 ng/L, and 0.88 ng/L, respectively. Limits of quantification (LOQ) for primidone, diclofenac, testosterone, and progesterone were 14.72 ng/L, 17.06 ng/L, 1.766 ng/L, and 2.813 ng/L, respectively. Average recoveries in environmental water and wastewater samples were greater than 74% and RSD were ≤ 7%. Trace levels (68.33–125.70 ng/L) of primidone were detected in four environmental water samples, whereas diclofenac was not detected in any of the tested sample. Trace levels of progesterone were observed in two environmental samples (16.64 – 203.73 ng/L), whereas testosterone was detected in STP inlet sample (178.16 ng/L)

DC & transient circuit simulation methodologies for organic electronics

This work establishes a novel circuit simulation methodology for organic thin film transistors (OTFTs). Because of a lack of well developed physical models for OTFTs and due to the limitations of conventional parameter extraction techniques, the approaches presented in this work come in handy for circuit designers. The first approach uses a look-up table (LUT) model, which is implemented in a general purpose public-domain circuit simulator SEQUEL (solver for circuit equations with user-defined elements). In the second approach, circuit simulation is performed using equivalent SPICE parameters, which are extracted using a global optimization technique namely particle swarm optimization (PSO) algorithm. A good match has been observed between LUT simulations and SPICE based circuit simulations for both DC and transient cases

Self-assembled hierarchical nanostructured perovskites enable highly efficient LEDs via an energy cascade

Metal halide perovskites have established themselves as extraordinary optoelectronic materials, exhibiting promise for applications in large area illumination and displays. However, low luminescence, low efficiencies of the light-emitting diodes (LEDs), and complex preparation methods currently limit further progress towards applications. Here, we report on a new and unique mesoscopic film architecture featuring the self-assembly of 3D formamidinium lead bromide (FAPbBr3) nanocrystals of graded size, coupled with microplatelets of octylammonium lead bromide perovskites that enables an energy cascade, yielding very high-performance light-emitting diodes with emission in the green spectral region. These hierarchically structured perovskite films exhibit photoluminescence quantum yields of over 80% and LEDs associated with record high efficiencies in excess of 57.6 cd A−1 with an external quantum efficiency above 13%. Additionally, due to low turn-on voltages (~2.2 V) the LEDs have power efficiencies exceeding 58 lumens per Watt, obtained without any light-outcoupling structures.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)Accepted versio

Data for Investigating the structure-function relationship in triple cation perovskite nanocrystals for light-emitting diode applications

Organic metal halide perovskite nanocrystals are promising candidates for light-emitting diodes due to their narrow emission bandwidth, high photoluminescence quantum yield (PLQY), and color tunability. Nevertheless, these systems suffer from thermal instability, phase impurities, and a sensitivity to processing techniques. This study reports the first synthesis of novel Cs-containing triple cation perovskite nanocrystals with nominal stoichiometry Csx(MA0.17FA0.83)1−xPbBr3 (x = 0–0.15). The effect of Cs+ cation incorporation is thoroughly investigated using diffraction, microscopy and solid state MAS NMR techniques. The solid state 133Cs MAS NMR results reveals the distribution of the Cs+ cations is highly concentration and particle size dependent, with maximized surface/subsurface Cs+ concentrations being achieved with the smaller 5 mol% Cs system. These characteristics directly correlate improved surface passivation and environmental stability of the triple cation system. These triple cation nanocrystals exhibit a maximum photoluminescence quantum yield of ∼93% which upon translation to nanocrystalline LED devices delivers a maximum EQE of 7.4% (30 cd A−1) corresponding to a power efficiency of 34.87 lm W−1. This performance represents a marked improvement compared to CsPbBr3 nanocrystals (PL quantum yield ∼50%; maximum EQE of 2.5% (7.2 cd A−1)) fabricated under similar conditions

Precise control of CsPbBr3 perovskite nanocrystal growth at room temperature : size tunability and synthetic insights

Room-temperature perovskite nanocrystal syntheses have previously lacked the size tunability attainable through high-temperature methods. Herein, we outline a scalable approach whereby the nucleation and growth of CsPbBr3 nanocrystals (NCs) can be decoupled and controlled at room temperature by utilizing different ligands. We employed octylphosphonic acid (OPA) ligands to regulate the critical radius and the NC growth rate. The subsequent addition of a bulkier didodecyldimethylammonium bromide ligand quenches the NC growth, defining the reaction duration. Management of these three variables enables precise tuning of the NC diameter between 6.8 and 13.6 nm. The photoluminescence quantum yield of the NCs remains above 80% for all sizes even after thorough antisolvent purification. The use of hydrogen-bonding OPA ligands enhances quantum confinement effects, characterized by strong, well-resolved absorption peaks. Solution and solid-state nuclear magnetic resonance spectra confirmed the effective removal of unbound ligands during purification and the presence of a hydrogen-bonded network of OPA ligands on the surface of the purified NCs. Overall, this approach has the potential to facilitate a broad range of future endeavors from studies of hot carrier dynamics to both optically and electrically driven device applications.Accepted versio

Nanoparticle-induced grain growth of carbon-free solution-processed CuIn(S,Se)2 solar cell with 6% efficiency

Chalcopyrite-based solar cell deposited by solution processes is of great research interest due to ease of fabrication and cost effectiveness. Despite the initial promising results, most of the reported methods encounter challenges such as limited grain growth, Carbon-rich interlayer, high thermal budget and the presence of secondary Cu-rich phases, which limit the power conversion efficiency (PCE). In this paper, we develop a new technique to deposit large grain, Carbon-free CISSe absorber layers from aqueous nanoparticle/precursor mixture which resulted in a solar cell with PCE of 6.2%. CuCl2, InCl3, and thiourea were mixed with CuS and In2S3 nanoparticles in water to form the unique nanoparticle/precursor solution. The Carbon layer formation was prevented because organic solvents were not used in the precursor. The copper-rich (CuS) nanoparticles were intentionally introduced as nucleation sites which accelerate grain growth. In the presence of nanoparticles, the grain size of CISSe film increased by a factor of 7 and the power conversion efficiency of the solar cell is 85% higher than the device without nanoparticle. This idea of using nanoparticles as a means to promote grain growth can be further exploited for other types of chalcopyrite thin film deposited by solution methods.Accepted versio