Insertion Rate Research Articles

Heterologous Single-Strand DNA-Annealing and Binding Protein Enhance CRISPR-Based Genome Editing Efficiency in Komagataella phaffii.

The industrial yeast Komagataella phaffii is a highly effective platform for heterologous protein production, owing to its high protein expression and secretion capacity. Heterologous genes and proteins are involved in multiple processes, including transcription, translation, protein folding, modification, transportation, and degradation; however, engineering these proteins and genes is challenging due to inefficient genome editing techniques. We employed Pseudomonas aeruginosa phage single-stranded DNA-annealing protein (SSAP) PapRecT and P. aeruginosa single-stranded DNA-binding protein (SSB) PaSSB to introduce SSAP-SSB-based homology recombination, which facilitated K. phaffii CRISPR-based genome engineering. Specifically, a host-independent method was developed by expressing sgRNA with PapRecT-PaSSB in a single plasmid, with which only a 50 bp short homologous arm (HA) reached a 100% positive rate for CRISPR-based gene insertion, reaching 18 colony-forming units (CFU) per μg of donor DNA. Single deletion using 1000 bp HA attained 100%, reaching 68 CFUs per μg of donor DNA. Using this efficient CRISPR-based genome editing tool, we integrated three genes (INO4, GAL4-like, and PAB1) at three different loci for overexpression to realize the collaborative regulation of human-lactalbumin (α-LA) production. Specifically, we strengthened phospholipid biosynthesis to facilitate endoplasmic reticulum membrane formation and enhanced recombinant protein transcription and translation by overexpressing transcription and translation factors. The final production of α-LA in the 3 L fermentation reached 113.4 mg L-1, two times higher than that of the strain without multiple site gene editing, which is the highest reported titer in K. phaffii. The CRISPR-based genome editing method developed in this study is suitable for the synergistic multiple-site engineering of protein and biochemical biosynthesis pathways to improve the biomanufacturing efficiency.

Assessing the manufacturable 32-channel cochlear electrode array: evaluation results for clinical trials.

Reliability evaluation results of a manufacturable 32-channel cochlear electrode array are reported in this paper. Applying automated laser micro-machining process and a layer-by-layer silicone deposition scheme, authors developed the manufacturing methods of the electrode array for fine patterning and mass production. The developed electrode array has been verified through the requirements specified by the ISO Standard 14708-7. And the insertion trauma of the electrode array has been evaluated based on human temporal bone studies. According to the specified requirements, the electrode array was assessed through elongation & insulation, flexural, and fatigue tests. In addition, Temporal bone study was performed using eight fresh-frozen cadaver temporal bones with the electrode arrays inserted via the round window. Following soaking in saline condition, the impedances between conducting wires of the electrode array were measured over 100 kΩ (the pass/fail criterion). After each required test, it was shown that the electrode array maintained the electrical continuity and insulation condition. The average insertion angle of the electrode array inside the scala tympani was 399.7°. The human temporal bone studies exhibited atraumatic insertion rate of 60.3% (grade 0 or 1). The reliability of the manufacturable electrode array is successfully verified in mechanical, electrical, and histological aspects. Following the completion of a 32-channel cochlear implant system, the performance and stability of the 32-channel electrode array will be evaluated in clinical trials.

Atomistic modeling of helium bubble network formation in copper

The helium (He) bubble network formation process in bulk copper (Cu) is investigated using atomistic simulations. Self-interstitial atoms (SIAs) emitted by trap mutation during the growth process of a single He bubble change surrounding lattices and stress fields and affect the transport of nearby He atoms. Interstitial He atoms or dimers can become trapped by deformed lattices and become nucleation sites for new He bubbles. The interaction of He with SIAs mutually hinders their movements. Finally, a distributed network of He bubbles, which are mostly formed along stacking fault edges, is generated. System temperature and He insertion rate have significant influences on this network.

Trends in surgical ablation at the time of cardiac surgery among patients with atrial fibrillation

BackgroundThe 2017 American Association for Thoracic Surgery (AATS) guidelines support surgical ablation in patients undergoing cardiac surgery with preoperative atrial fibrillation (AF) owing to a reduction in early mortality and improved overall safety. We explored practice patterns changes and outcomes in patients undergoing concomitant surgical ablation following the guideline change. MethodsWe identified 19,246 patients with preoperative AF who underwent cardiac surgery between 2016 and 2019 from the Florida and Maryland State Inpatient Databases. Rates of surgical ablation by procedure type were temporally trended across years. Secondary outcomes included complications, inpatient mortality, and hospital readmissions. Using multivariable logistic regression, we identified patient variables associated with concomitant surgical ablation. ResultsA total of 2738 patients (14.3%) with AF underwent a concomitant surgical ablation. The rate of surgical ablation increased from 2.1% to 17.4% (P < .001) from 2016 to 2017 but remained unchanged thereafter. Postoperative mortality was lower in the surgical ablation cohort (2.7% vs 3.7%; P = .006), although with a higher rate of pacemaker insertion (11.8% vs 7.2%; P < .0001). Patients with a high-risk Elixhauser score (odds ratio [OR], 0.83; 95% confidence interval [CI], 0.73-0.95), lower income (OR, 0.66; 95% CI, 0.57-0.75), or African American or Hispanic race/ethnicity (OR, 0.80; 95% CI, 0.67-0.96 and OR, 0.82; 95% CI, 0.71-0.96, respectively) had lower odds of undergoing concomitant surgical ablation. ConclusionsDespite a class I-2a recommendation by the AATS, surgical ablation continues to be underutilized in clinical practice, especially in patients with high-risk comorbidities, with lower incomes, or from minority populations. Surgeons should be mindful of guideline-directed AF management in these vulnerable populations.

Vitamin C activates young LINE-1 elements in mouse embryonic stem cells via H3K9me3 demethylation

BackgroundVitamin C (vitC) enhances the activity of 2-oxoglutarate-dependent dioxygenases, including TET enzymes, which catalyse DNA demethylation, and Jumonji-domain histone demethylases. The epigenetic remodelling promoted by vitC improves the efficiency of induced pluripotent stem cell derivation, and is required to attain a ground-state of pluripotency in embryonic stem cells (ESCs) that closely mimics the inner cell mass of the early blastocyst. However, genome-wide DNA and histone demethylation can lead to upregulation of transposable elements (TEs), and it is not known how vitC addition in culture media affects TE expression in pluripotent stem cells.ResultsHere we show that vitC increases the expression of several TE families, including evolutionarily young LINE-1 (L1) elements, in mouse ESCs. We find that TET activity is dispensable for L1 upregulation, and that instead it occurs largely as a result of H3K9me3 loss mediated by KDM4A/C histone demethylases. Despite increased L1 levels, we did not detect increased somatic insertion rates in vitC-treated cells. Notably, treatment of human ESCs with vitC also increases L1 protein levels, albeit through a distinct, post-transcriptional mechanism.ConclusionVitC directly modulates the expression of mouse L1s and other TEs through epigenetic mechanisms, with potential for downstream effects related to the multiple emerging roles of L1s in cellular function.

Precision and Safety of Ultrasound-Guided versus Palpation-Guided Needle Placement on the Patellar Tendon: A Cadaveric Study.

For decades, needling interventions have been performed based on manual palpation and anatomic knowledge. The increasing use of real-time ultrasonography in clinical practice has improved the accuracy and safety of needling techniques. Although currently ultrasound-guided procedures are routinely used for patellar tendon pathology, e.g., during percutaneous electrolysis, the accuracy of these procedures is still unknown. This study used a cadaveric model to compare and evaluate both the accuracy and safety of ultrasound-guided and palpation-guided needling techniques for the patellar tendon. A total of five physical therapists performed a series of 20 needle insertion task each (n = 100), 10 insertions based on manual palpation (n = 50) and 10 insertions guided with ultrasound (n = 50) to place a needle along the interface between the patellar tendon and Hoffa's fat pad. All procedures were performed on cryopreserved knee specimens. Distance to the targeted tissue, time of the procedure, accurate rate of insertions, number of passes, and unintentional punctured structures between both applications (with and without ultrasound guiding) were compared. The results revealed higher accuracy (100% vs. 80%), a lower distance from needle to the targeted tissue (0.25 ± 0.65 vs. 2.5 ± 1.9 mm), longer surface of contact with the needle (15.5 ± 6.65 vs. 4.7 ± 7.5 mm), and a lower frequency of patellar tendon puncture (16% vs. 52%, p < 0.001) with the ultrasound-guided procedure as opposed to palpation-guided one. Nevertheless, the ultrasound-guided procedure took longer (54.8 ± 26.8 vs. 23.75 ± 15.4 s) and required more passes (2.55 ± 1.9 vs. 1.5 ± 0.95) to be conducted than the palpation-guided procedure (all, p < 0.001). According to these findings, the accuracy of invasive procedures applied on the patellar tendon is higher when conducted with ultrasound guidance than when conducted just on manual palpation or anatomical landmark. These results suggest that ultrasound could improve the clinical application of invasive procedures at the fat-patellar tendon interface. Due to the anatomical features of the targeted tissue, some procedures require this precision, so the use of ultrasound is recommended.

Intra-pocket ultrasound-guided axillary vein puncture vs. cephalic vein cutdown for cardiac electronic device implantation: the ACCESS trial.

Intra-pocket ultrasound-guided axillary vein puncture (IPUS-AVP) for venous access in implantation of transvenous cardiac implantable electronic devices (CIED) is uncommon due to the lack of clinical evidence supporting this technique. This study investigated the efficacy and early complications of IPUS-AVP compared to the standard method using cephalic vein cutdown (CVC) for CIED implantation. ACCESS was an investigator-led, interventional, randomized (1:1 ratio), monocentric, controlled superiority trial. A total of 200 patients undergoing CIED implantation were randomized to IPUS-AVP (n = 101) or CVC (n = 99) as a first assigned route. The primary endpoint was the success rate of insertion of all leads using the first assigned venous access technique. The secondary endpoints were time to venous access, total procedure duration, fluoroscopy time, X-ray exposure, and complications. Complications were monitored during a follow-up period of three months after procedure. IPUS-AVP was significantly superior to CVC for the primary endpoint with 100 (99.0%) vs. 86 (86.9%) procedural successes (P = .001). Cephalic vein cutdown followed by subclavian vein puncture was successful in a total of 95 (96.0%) patients, P = .21 vs. IPUS-AVP. All secondary endpoints were also significantly improved in the IPUS-AVP group with reduction in time to venous access [3.4 vs. 10.6 min, geometric mean ratio (GMR) 0.32 (95% confidence interval, CI, 0.28-0.36), P < .001], total procedure duration [33.8 vs. 46.9 min, GMR 0.72 (95% CI 0.67-0.78), P < .001], fluoroscopy time [2.4 vs. 3.3 min, GMR 0.74 (95% CI 0.63-0.86), P < .001], and X-ray exposure [1083 vs. 1423 mGy.cm², GMR 0.76 (95% CI 0.62-0.93), P = .009]. There was no significant difference in complication rates between groups (P = .68). IPUS-AVP is superior to CVC in terms of success rate, time to venous access, procedure duration, and radiation exposure. Complication rates were similar between the two groups. Intra-pocket ultrasound-guided axillary vein puncture should be a recommended venous access technique for CIED implantation.

Synthesis and dynamic crosslinking of a hydroxyl-functionalized ethylene-propylene copolymer: Preparation of an elastomer with reprocessability and shape memory properties

The ternary copolymers of ethylene, propylene and 10-undecen-1-ol were prepared using a vanadium catalyst bearing an 8-anilide-5,6,7-trihydroquinoline ligand. By adjusting the concentration of 10-undecen-1-ol and polymerization temperature, the insertion rate of polar monomers was modulated with a maximum value of 3.8% achieved for 10-undecen-1-ol. With an increase in the hydroxyl insertion rate, the water contact angle of hydroxyfunctionalized ethylene-propylene copolymers decreased from 112.3° to 95.3°, indicating that the incorporation of 10-undecen-1-ol enhanced the hydrophilicity of the copolymers. Subsequently, a reprocessable ethylene-propylene rubber (EPR) with double dynamic bonds was synthesized through reaction between the hydroxyl group on functionalized ethylene-propylene copolymer and the crosslinking agent using isocyanate as chain end. The strength of functionalized ethylene-propylene copolymers was significantly improved through dynamic crosslinking. Significantly, the tensile strength of sample EP6-V-0.5 reached 14 MPa, which was 27 times higher than that of un-crosslinked EP6. The prepared functionalized ethylene-propylene rubber prepared exhibited not only reprocessability, but also remarkable shape memory and reshaping properties. Moreover, the conductive composite materials based on this rubber displayed great potential for application in motion sensors.

Pulmonary Hypertension Is Associated with Worse Outcomes in Patients Hospitalized for Sick Sinus Syndrome.

Sick sinus syndrome (SSS) is a condition of the sinoatrial node that arises from a constellation of aberrant rhythms, resulting in reduced pacemaker activity and impulse transmission. According to the World Health Organization, pulmonary hypertension (PH) is defined by a mean pulmonary arterial pressure of >25 mmHg at rest, measured during right heart catheterization. It can result in right atrial remodeling, which may predispose the patient to sinus node dysfunction. This study sought to estimate the impact of PH on clinical outcomes of hospitalizations with SSS. The U.S. National Inpatient Sample database from 2016-2019 was searched for hospitalized adult patients with SSS as a principal diagnosis with and without PH as a secondary diagnosis using the International Classification of Diseases, Tenth Revision, codes. The primary outcome was inpatient mortality. The secondary outcomes were acute kidney injury (AKI), cardiogenic shock (CS), cardiac arrest, rates of pacemaker insertion, total hospital charges (THCs), and length of stay (LOS). Multivariate regression analysis was used to adjust for confounders. A total of 181,230 patients were admitted for SSS; 8.3% (14,990) had underlying PH. Compared to patients without PH, patients admitted with coexisting PH had a statistically significant increase in mortality (95% confidence interval, 1.21-2.32; P = .002), AKI (P < .001), CS (P = .004), THC (P = .037), and LOS (P < .001). In conclusion, patients admitted primarily for SSS with coexisting PH had a statistically significant increase in mortality, AKI, CS, THC, and LOS. Additional studies geared at identifying and addressing the underlying etiologies for PH in this population may be beneficial in the management of this patient group.

Application and effectiveness of an improved endoscopically guided nasojejunal tube placement technique in critically ill patients: a retrospective cohort study.

The endoscopic nasojejunal (NJ) placement plays a pivotal role in the nutritional support of critically ill patients. However, the conventional endoscopy-guided tube insertion method presents issues of excessive procedural duration. We have enhanced the traditional endoscopy-guided catheter placement method, enabling a faster and more convenient catheter insertion. We improved the traditional endoscopically guided technique by incorporating an extra silk thread knot at the 25 cm mark on the jejunal segment of the NJ tube to assist endoscopists in accurate tube placement. We conducted the improved NJ tube placement on critically ill patients in need of enteral nutrition (EN). Laboratory data were retrospectively collected before and after the 7-day period of NJ tube placement and EN treatment to evaluate the effectiveness and safety of the improved method. A total of 88 critically ill patients, with an average age of 59.6±15.5 years, and a male ratio of 86.4%, who underwent the improved NJ tube placement method were enrolled into analysis finally, achieving a 100% success rate of NJ tube insertion. The average time for tube insertion was 5.9±2.2 min, with a mean insertion depth of 108.8±12.5 cm. The EN tolerance score was 0.79±0.98. Following 7 days of EN therapy, the patients showed significant improvement in serum albumin levels compared to baseline (36.42 vs. 33.66 g/L, P<0.001). The improved endoscopically guided NJ tube placement technique is a rapid and safe procedure with excellent patient tolerance. It significantly improves the nutritional status of critically ill patients and facilitates the administration of EN, which requires further validation through randomized controlled trials.

Transcallosal approach and post-operative subdural collections: 12-year paediatric neurosurgery tertiary centre experience.

Following transcallosal surgery for tumour resection, the formation of convexity or interhemispheric subdural cerebrospinal fluid collections may lead to clinical deterioration and may influence decision-making with regards to additional interventions. The aim of this study was to determine the incidence, risk factors, and management of subdural collections following the transcallosal approach in a paediatric cohort. A retrospective case note and radiological review of all children who underwent transcallosal surgery for intraventricular and thalamic tumours was carried out covering a 12-year period (2012-2023) in a single-centre tertiary paediatric neurosurgery unit. Parameters including demographics and clinical information including lesion location, pathology, extent of resection, need for and type of shunt required, as well as depth, laterality, and location of the collection were analysed prior to shunting, and at approximately 3 weeks, 3 months, and latest follow-up available post-operatively in order to further elucidate the natural history of these subdural collections and their clinical significance. Sixty-four cases satisfied the inclusion criteria of transcallosal surgery for tumour resection; 13 did not have adequate post-operative imaging and were excluded. Of the remaining 51 cases, there were 32 children (63%) with post-operative CSF subdural collections, of which 59% were ipsilateral, with the remainder showing bilateral distribution. The overall shunt insertion rate was 25.5% (12 ventriculoperitoneal and 1 subdural-peritoneal shunt) at 3 months, with a mean time to shunting of 19 days post-operatively. Children who developed post-operative subdural collections had a higher rate of shunting, at 37.5%, compared to 5.2% in those who did not. Pre- and post-operative hydrocephalus and subtotal resection were identified as risk factors for development of subdural collections post-operatively. Subdural collections showed a natural course of reduction and regression over follow-up, with the exception of 3 children where they persisted or increased over time; although none of these required shunting. Those children who underwent shunt insertion showed greater regression in the size of the subdural collection over time compared to the non-shunted group. In this paediatric cohort, 25.5 % of children required insertion of a shunt by 3 months following transcallosal surgery. Pre- and post-operative hydrocephalus and subtotal tumour resection were risk factors for development of subdural collections post-operatively.

Value of a novel Y-Z magnetic totally implantable venous access port in improving the success rate of one-time needle insertion.

A totally implantable venous access port (TIVAP) is a commonly used intravenous infusion device for patients receiving chemotherapy or long-term infusion therapy. To improve the success rate of one-time insertion of the Huber needle, we developed a novel Y-Z magnetic TIVAP (Y-Z MTIVAP), which we produced using three-dimensional printing technology. The Y-Z MTIVAP includes a magnetic port body and a magnetic positioning device. For testing, we established four venous port implantation models using the two types of TIVAPs and two implantation depth ranges (≤5 mm and >5 mm). Twenty nurses performed Huber needle puncture with the four models, and we recorded the number of attempts required for successful needle insertion, the operation time, and the operator's satisfaction. The success rate for one-time needle insertion with the Y-Z MTIVAP was significantly higher than that with the traditional TIVAP at either depth range (100% vs. 75% at ≤5 mm, p = 0.047; 95% vs. 35% at >5 mm, p < 0.001). With increasing implantation depth, the success rate for one-time insertion was significantly reduced with the traditional TIVAP (75% at ≤5 mm vs. 35% vs. >5 mm, p = 0.025), but the success rate with the Y-Z MTIVAP was not significantly affected (100% vs. 95%, p = 1.000). The operation time with the Y-Z MTIVAP was significantly shorter than that with the traditional TIVAP at either depth range (both p < 0.001), and 90% of operators reported that the Y-Z MTIVAP was superior to the traditional TIVAP. The theoretical design of Y-Z MTIVAP is feasible, and the preliminary in vitro simulation experiment shows that it can significantly improve puncture success rate and shortened operation time.

The safe implementation of peripherally inserted central catheters by nurse practitioners for patients with gastroenterological diseases in Japan: a single-center retrospective study.

As a safe and reliable alternative to central venous catheters (CVCs), peripherally inserted central catheters (PICCs) are commonly used in clinical practice. However, the insertion of PICCs by nurse practitioners (NPs), especially in Japan, has not been reported extensively. Thus, we investigated the safety and efficiency of PICC insertions by NPs. The participants were 1322 patients who underwent PICC insertion by NPs at Fujita Health University Hospital (FNPs). The basilic vein in the brachium was the preferred vein for insertion; the brachial vein was the alternative. Patients were monitored from the time of PICC insertion until its removal. Ultrasonography-guided puncture was used for all catheter insertions, and the catheter tip was replaced into the superior vena cava under fluoroscopic imaging with maximal sterile barrier precautions. The outcomes of the PICC insertions by the FNPs were evaluated retrospectively. Overall, 23 FNPs inserted a collective total of 1322 PICCs, which remained in place for a collective total of 23,619 catheter days. The rate of successful PICC insertion was 99% (1310 patients). The median time taken for PICC insertion was 12min (interquartile range, 10-15min). Intraoperative complications occurred in two patients (0.2%). The confirmed incidence of central line-associated bloodstream infection was 3.4% (45 patients), and these infections occurred on 1.9 per 1000 catheter days. The median duration of PICC placement was 15days (range, 10-23days). PICC insertion by NPs is safe and a potential alternative to CVC insertion by surgeons.

Insertional Variations of Human Endogenous Virus K6 and K11 in Normozoospermic Men.

Male infertility is a multifactorial heterogeneous reproductive disorder in which genetic, epigenetic, and environmental factors play a role in the development of disease. Recent studies have shown that retrotransposon expression alterations may be related to impairment of spermatogenesis. Therefore, in this pilot study, we aimed to investigate whether HERV-K6 and HERV-K11 insertional variations have a role in idiopathic infertility among normozoospermic men. Genomic DNA isolated from the blood samples of 41 infertile normozoospermic and 45 fertile normozoospermic men were analyzed by inter-retrotransposon polymorphism polymerase chain reaction. HERV-K6 variation rates in the infertile and the fertile group were 0-58.3% and 0-53.4%, respectively. The variation rates of HERV-K11 were 0-75.0% in infertile and 0-77.8% in fertile men. The HERV-K6 and HERV-K11 insertion rates of the fertile group were higher than the infertile group (P < 0.0001 and P = 0.007, respectively). The findings of the study suggest that HERV-K6 and HERV-K11 retrotransposon insertion show variation among individuals, and their insertions might be associated with male infertility.

Arene Insertion with Pincer-Supported Molybdenum-Hydrides: Determination of Site Selectivity, Relative Rates, and Arene Complex Formation.

The synthesis of phosphino(oxazoline)pyridine-supported molybdenum(0) cycloocta-1,5-diene complexes is described. Exposure of these complexes to dihydrogen in the presence of an arene resulted in insertion of the substrate into the molybdenum hydride bond and afforded the corresponding molybdenum cyclohexadienyl hydrides. For mono- and disubstituted arenes, the site selectivity for insertion of the most substituted bond increases with increasing size of the substituent from methyl to ethyl, iso-propyl, and tert-butyl. In contrast, 1,3,5-trisubstituted arenes underwent insertion with exclusive site selectivity. Relative rates of insertion were determined by competition experiments and established faster insertions for electron-rich arenes. Introduction of electron-withdrawing trifluoromethyl groups on the arene resulted in decreased relative rates of insertion and an increased rate for H2 reductive elimination, favoring formation of the corresponding molybdenum η6-arene complex. Studies on the reductive elimination of the cyclohexadienyl ligand with the hydride enabled the synthesis of an enantioenriched cyclohexa-1,3-diene. This study provides new insights into the ligand requirements for catalytic arene hydrogenation and a new strategy for selective arene reduction.

Safety and efficacy of intraperitoneal drain placement after emergency colorectal surgery: An international, prospective cohort study.

Intraperitoneal drains are often placed during emergency colorectal surgery. However, there is a lack of evidence supporting their use. This study aimed to describe the efficacy and safety of intraperitoneal drain placement after emergency colorectal surgery. COMPlicAted intra-abdominal collectionS after colorectal Surgery (COMPASS) is a prospective, international, cohort study into which consecutive adult patients undergoing emergency colorectal surgery were enrolled (from 3 February 2020 to 8 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 III-V). Multivariable logistic and Cox proportional hazards regressions were used to estimate the independent association of the outcomes with drain placement. Some 725 patients (median age 68.0 years; 349 [48.1%] women) from 22 countries were included. The drain insertion rate was 53.7% (389 patients). Following multivariable adjustment, drains were not significantly associated with reduced rates (odds ratio [OR] = 1.56, 95% CI: 0.48-5.02, p = 0.457) or earlier detection (hazard ratio [HR] = 1.07, 95% CI: 0.61-1.90, p = 0.805) of collections. Drains were not significantly associated with worse major postoperative complications (OR = 1.26, 95% CI: 0.67-2.36, p = 0.478), delayed hospital discharge (HR = 1.11, 95% CI: 0.91-1.36, p = 0.303) or increased risk of SSIs (OR = 1.61, 95% CI: 0.87-2.99, p = 0.128). This is the first study investigating placement of intraperitoneal drains following emergency colorectal surgery. The safety and clinical benefit of drains remain uncertain. Equipoise exists for randomized trials to define the safety and efficacy of drains in emergency colorectal surgery.

Remote Steric and Electronic Effects of N-Heterocyclic Carbene Ligands on Alkene Reactivity and Regioselectivity toward Hydrocupration Reactions: The Role of Expanded-Ring N-Heterocyclic Carbenes.

The remote groups in N-heterocyclic carbene (NHC) ligands have a significant influence on metal-catalyzed reactions. We examine how remote bulkiness, electronic groups, and expanded-ring NHCs (ER-NHCs) influence alkene reactivity and regioselectivity toward hydrocupration using density functional theory calculations. The impact of remote steric bulkiness on the Cu-H insertion rate is analyzed, revealing a strong correlation between the steric substituent constant and rate ratio, where a bulky group increases the rate due to reduced steric effects in the transition state (TS). The steric properties of the examined catalysts (with a remote group R2 = CPh3, CHPh2, CH2Ph, CH3, and H) and their corresponding TSs are found to be modulated greatly by the remote steric substitution group and the ring size of the NHC ligand. Enhanced bulkiness enhances the nucleophilic Cu-H moiety. The remote electronic groups have a smaller impact on insertion barrier compared to that of steric hindrance. Furthermore, ER-NHC exploration indicates that NHCs with over five-membered rings have a significantly negative influence on the reaction rate. Finally, with a highly bulky group (R2 = CPh3), anti-Markovnikov insertion preference is attributed to high interaction energy and improved steric properties. Overall, our findings here provide valuable insights for the development of a more effective catalyst in metal-catalyzed reactions.

Steps to improve umbilical vein catheterization in neonatal care

IntroductionIn neonatal units, umbilical vessel catheterization is the preferred method to gain vascular access in the initial management of the newborn because it is quick and easy.The failure rate ranges from to 50%, as the catheter can be found in the portal system in up to 40% of cases, leading to complications. This failure rate warrants the investigation of different methods to reduce the frequency of catheter malposition. We describe different techniques to improve the success rate in umbilical vein catheterization, such as the double catheter technique, positioning the newborn in right lateral decubitus for insertion, liver compression, and ultrasound-guided catheter insertion. The primary objective of the study was to assess the impact of new techniques on the success rate of central umbilical venous catheterization. Material and methodsPre- and post-intervention quasi-experimental study in a level B NICU conducted in January-June 2022 (pre-intervention) and July-December 2022 (post-intervention). ResultsPrior to the introduction of these new catheterization techniques, the failure rate of blind umbilical catheter insertion was 52%. Since the introduction of these measures, the overall failure rate has decreased to 27%. ConclusionsAfter the introduction of the new catheterization and recanalization methods, our success rate in umbilical vein catheterization has increased, and we believe it is necessary to implement them in units with similar failure rates to ours.

Modeling and Optimization of Surface Integrity and Sliding Wear Resistance of Diamond-Burnished Holes in Austenitic Stainless Steel Cylinder Lines

This article outlines a technology for hole-finishing in short-length cylinder lines to improve wear resistance. The technology is based on an optimized diamond-burnishing (DB) process. The latter was implemented on conventional and CNC lathes, milling machines, and machining centers using a simple burnishing device with an elastic beam. The material used in this study was AISI 321 austenitic stainless steel. The governing factors used were the radius of the diamond insert, burnishing force and feed rate. The objective functions relating to surface integrity characteristics were selected on the basis of their functional importance relative to the wear resistance of the processed hole surface: height and shape roughness parameters, surface microhardness, and surface residual axial and hoop stresses. The one-factor-at-a-time method (used to reduce the factor space), a planned experiment, and regression analyses were used. The multi-objective optimization tasks, which were defined for three diamond insert radius values of 2, 3, and 4 mm, were solved via the Pareto-optimal solutions approach available for a non-dominated sorting genetic algorithm (NSGA-II). Using the optimal values of the governing factors selected from the Pareto fronts, cylinder lines were processed. Samples were then cut from these cylinder lines for reciprocating sliding wear tests under two modes: dry friction and boundary lubrication friction. Additionally, wear test samples were cut from the cylinder line, which was finished with traditional grinding. A finite element simulation was then used to select an appropriate pressing force. The results obtained from the reciprocating sliding wear tests under both the dry and boundary lubrication friction regimes show that to minimize the wear on cylinder lines made of AISI 321 steel, DB with a diamond insert of radius 2 mm is the optimal finishing process.

Compliance With Percutaneous Endoscopic Gastrostomy Tube Insertion Guidelines and Associated Complications in a Tertiary Care Setting: A Clinical Audit.

Percutaneous endoscopic gastrostomy (PEG) tube insertion is a widely utilized enteral access technique offering long-term nutritional support for patients unable to tolerate oral intake. While the PEG tube provides numerous advantages, adherence to evidence-based guidelines is crucial to minimize complications. This study aims to evaluate adherence to PEG tube insertion guidelines and analyze associated complication rates in a tertiary care setting. A retrospective clinical audit was conducted at Quaid-e-Azam International Hospital, Islamabad. Data were collected over three years from patients undergoing PEG tube insertion by a single consultant gastrointestinal surgeon. Adherence to guidelines was evaluated using a 10-item checklist developed based on European Society of Gastrointestinal Endoscopy (ESGE) guidelines. Complication rates and patient characteristics were analyzed. The study included 70 participants (mean age = 72.21 ± 13.17). The PEG tube insertion rate was 100%. The mean checklist score was 8.34 ± 1.2. Laboratory investigations were performed for 98.6% of patients. 91.4% of patients had a life expectancy exceeding 30 days. 60% of patients received an anticoagulation hold. Prophylactic antibiotics were administered to 90% of patients. Psychological counseling and dietician consultation were offered to 38.6% and 64.2% of patients, respectively. Caregivers received specialized training in 98.5% of cases. 12.8% of patients experienced early complications post-procedure, and 14.2% experienced late complications. PEG tube removal occurred in 27% of patients, with only one patient experiencing complications after removal. Adherence to PEG tube insertion guidelines was observed in various aspects of patient care, resulting in a low incidence of complications. Comprehensive auditing and guideline adherence are essential to ensure optimal patient safety and procedural outcomes.