Consecutive Insertions Research Articles

A Complementary Fusion-Based Multimodal Non-Destructive Testing and Evaluation Using Phased-Array Ultrasonic and Pulsed Thermography on a Composite Structure.

Combinative methodologies have the potential to address the drawbacks of unimodal non-destructive testing and evaluation (NDT & E) when inspecting multilayer structures. The aim of this study is to investigate the integration of information gathered via phased-array ultrasonic testing (PAUT) and pulsed thermography (PT), addressing the challenges posed by surface-level anomalies in PAUT and the limited deep penetration in PT. A center-of-mass-based registration method was proposed to align shapeless inspection results in consecutive insertions. Subsequently, the aligned inspection images were merged using complementary techniques, including maximum, weighted-averaging, depth-driven combination (DDC), and wavelet decomposition. The results indicated that although individual inspections may have lower mean absolute error (MAE) ratings than fused images, the use of complementary fusion improved defect identification in the total number of detections across numerous layers of the structure. Detection errors are analyzed, and a tendency to overestimate defect sizes is revealed with individual inspection methods. This study concludes that complementary fusion provides a more comprehensive understanding of overall defect detection throughout the thickness, highlighting the importance of leveraging multiple modalities for improved inspection outcomes in structural analysis.

RNA editing catalytic complexes edit multiple mRNA sites non-processively in Trypanosoma brucei

RNA editing generates mature mitochondrial mRNAs in T. brucei by extensive uridine insertion and deletion at numerous editing sites (ESs) as specified by guide RNAs (gRNAs). The editing is performed by three RNA Editing Catalytic Complexes (RECCs) which each have a different endonuclease in addition to 12 proteins in common resulting in RECC1 that is specific for deletion ESs and RECC2 and RECC3 that are specific for insertion ESs. Thus, different RECCs are required for editing of mRNA sequence regions where single gRNAs specify a combination of insertion and deletion ESs. We investigated how the three different RECCs might edit combinations of insertion and deletion ESs that are specified by single gRNAs by testing whether their endonuclease compositions are stable or dynamic during editing. We analyzed in vivo BirA* proximity labeling and found that the endonucleases remain associated with their set of common RECC proteins during editing when expressed at normal physiological levels. We also found that overexpression of endonuclease components resulted in minor effects on RECCs but did not affect growth. Thus, the protein stoichiometries that exist within each RECC can be altered by perturbations of RECC expression levels. These results indicate that editing of consecutive insertion and deletion ESs occurs by successive engagement and disengagement of RECCs, i.e., is non-processive, which is likely the case for consecutive pairs of insertion or deletion ESs. This clarifies the nature of the complex patterns of partially edited mRNAs that occur in vivo.

Ultrasound based tip location of femorally inserted central catheters into the inferior vena cava: A comparison between the transhepatic and the subcostal view.

Intraprocedural catheter tip location is currently recommended. Intracavitary EGC and ultrasound are the preferred methods of tip location for catheters with their tip in the superior vena cava or in the right atrium. Though, the best method of intraprocedural tip location for catheters with their tip in the inferior vena cava is still uncertain. One possibility is to visualize the subdiaphragmatic inferior vena cava by ultrasound, using either the transhepatic or the subxiphoid view. In this prospective study, we compared two different ultrasound windows for the visualization of the inferior vena cava (transhepatic vs subxiphoid) for the purpose of localizing the catheter tip during the insertion of femorally inserted central catheters. We studied 249 consecutive insertions of central catheters via the superficial femoral vein. Intraprocedural location of the catheter tip was performed by ultrasound, using both transhepatic and subxiphoid view. Visualization of the inferior vena cava was possible only in 81 cases (32.5%) with the subxiphoid view, but it was always possible in all 249 cases with the transhepatic view. The catheter tip was localized in 15 patients out of 81 with the subxiphoid view (18.5%); the transhepatic view allowed the visualization of the tip in all 249 patients. The applicability of the subxiphoid window has several limitations, both in terms of visualization of the inferior vena cava and localization of the catheter tip. The transhepatic view should be the preferred method for intraprocedural ultrasound localization of the catheter tip in the inferior vena cava.

Loading dynamics of one SARS-CoV-2-derived peptide into MHC-II revealed by kinetic models

Major histocompatibility complex class II (MHC-II) plays an indispensable role in activating CD4+ T cell immune responses by presenting antigenic peptides on the cell surface for recognition by T cell receptors. The assembly of MHC-II and antigenic peptide is therefore a prerequisite for the antigen presentation. To date, however, the atomic-level mechanism underlying the peptide-loading dynamics for MHC-II is still elusive. Here, by constructing Markov state models based on extensive all-atom molecular dynamics simulations, we reveal the complete peptide-loading dynamics into MHC-II for one SARS-CoV-2 S-protein-derived antigenic peptide (235ITRFQTLLALHRSYL249). Our Markov state model identifies six metastable states (S1–S6) during the peptide-loading process and determines two dominant loading pathways. The peptide could potentially approach the antigen-binding groove via either its N- or C-terminus. Then, the consecutive insertion of several anchor residues into the binding pockets profoundly dictates the peptide-loading dynamics. Notably, the MHC-II αA52-E55 motif could guide the peptide loading into the antigen-binding groove via forming β-sheets conformation with the incoming peptide. The rate-limiting step, namely S5→S6, is mainly attributed to a considerable desolvation penalty triggered by the binding of the peptide C-terminus. Moreover, we further examined the conformational changes associated with the peptide exchange process catalyzed by the chaperon protein HLA-DM. A flipped-out conformation of MHC-II αW43 captured in S1–S3 is considered a critical anchor point for HLA-DM to modulate the structural dynamics. Our work provides deep structural insights into the key regulatory factors in MHC-II responsible for peptide recognition and guides future design for peptide vaccines against SARS-CoV-2.

Triple-Consecutive Isocyanide Insertions with Aldehydes: Synthesis of 4-Cyanooxazoles.

An efficient TMSOTf-promoted selective triple consecutive insertions of tert-butyl isocyanide into aldehydes has been developed, affording pharmacological interesting 4-cyanooxazoles in high yields in a one pot manner. The given method encompasses a wide range of substrates with tert-butyl isocyanide serving as sources of critical "CN" and "C-N═C" moieties. The versatile transformations of the resulting 4-cyanooxazoles were demonstrated. The key reaction intermediates for plausible mechanisms were determined.

Experimental demonstration of operon formation catalyzed by insertion sequence.

Operons are a hallmark of the genomic and regulatory architecture of prokaryotes. However, the mechanism by which two genes placed far apart gradually come close and form operons remains to be elucidated. Here, we propose a new model of the origin of operons: Mobile genetic elements called insertion sequences can facilitate the formation of operons by consecutive insertion–deletion–excision reactions. This mechanism barely leaves traces of insertion sequences and thus difficult to detect in nature. In this study, as a proof-of-concept, we reproducibly demonstrated operon formation in the laboratory. The insertion sequence IS3 and the insertion sequence excision enhancer are genes found in a broad range of bacterial species. We introduced these genes into insertion sequence-less Escherichia coli and found that, supporting our hypothesis, the activity of the two genes altered the expression of genes surrounding IS3, closed a 2.7 kb gap between a pair of genes, and formed new operons. This study shows how insertion sequences can facilitate the rapid formation of operons through locally increasing the structural mutation rates and highlights how coevolution with mobile elements may shape the organization of prokaryotic genomes and gene regulation.

A Quaternary Code Correcting a Burst of at Most Two Deletion or Insertion Errors in DNA Storage.

Due to the properties of DNA data storage, the errors that occur in DNA strands make error correction an important and challenging task. In this paper, a new code design of quaternary code suitable for DNA storage is proposed to correct at most two consecutive deletion or insertion errors. The decoding algorithms of the proposed codes are also presented when one and two deletion or insertion errors occur, and it is proved that the proposed code can correct at most two consecutive errors. Moreover, the lower and upper bounds on the cardinality of the proposed quaternary codes are also evaluated, then the redundancy of the proposed code is provided as roughly .

Hypervalent iodine mediated synthesis of imidazo[1,2-a]pyridine ethers: consecutive methylene linkage and insertion of ethylene glycol

Hypervalent iodine mediated selective synthesis of imidazo[1,2-a]pyridine ethers using ethylene glycol as a methoxy ethanol source as well as solvent under metal-free conditions is described.

Activation of MnO hexagonal nanoplates via in situ electrochemical charging toward high-capacity and durable Zn-ion batteries

Rechargeable aqueous Zn-MnO2 batteries hold great promise in grid-scale energy storage owing to their merits of high specific energy, inexpensiveness, environmental benignity, and high safety. However, MnO2 cathodes suffer from extremely poor cycling stability in pure ZnSO4 electrolyte. In this work, MnO hexagonal nanoplates constructed by porous nanocrystals are reported to show superior zinc-ion storage performance in pure ZnSO4 electrolyte. Mechanistic investigation reveals that the MnO cathode experiences an in situ gradual oxidation during electrochemical charging to form active MnO2 ultrathin nanosheets, which subsequently allow for a reversible and consecutive insertion of H+ and Zn2+. Notably, a high specific capacity of 292 mAh g−1 can be obtained in the activated cathode at a current density of 0.1 A g−1. In particular, the cathode could sustain a long 1000-cycling operation without noticeable capacity degradation, which is comparable to the reported MnO2 cathodes in an electrolyte containing MnSO4 additive. The present study will shed light on the development of low-valence Mn-oxides by in situ electrochemical charging toward high-capacity and durable zinc-ion batteries.

Effect of ultrasound-guided central venous catheter insertion on the incidence of catheter-related bloodstream infections and mechanical complications

BackgroundCentral venous catheters (CVCs) are necessary for critically ill patients, including those with hematological malignancies. However, CVC insertion is associated with inevitable risks for various adverse events. Whether ultrasound guidance decreases the risk of catheter-related infection remains unclear.MethodsWe observed 395 consecutive CVC insertions between April 2009 and January 2013 in our hematological oncology unit. Because the routine use of ultrasound guidance upon CVC insertion was adopted based on our hospital guidelines implemented after 2012, the research period was divided into before December 2011 (early term) and after January 2012 (late term).ResultsUnderlying diseases included hematological malignancies and immunological disorders. In total, 235 and 160 cases were included in the early- and late term groups, respectively. The median insertion duration was 26 days (range, 2–126 days) and 18 days (range, 2–104 days) in the early- and late term groups, respectively. The internal jugular, subclavian, and femoral veins were the sites of 22.6, 40.2, and 25.7% of the insertions in the early term group and 32.3, 16.9, and 25.4% of the insertions in the late term group, respectively. The frequency of catheter-related bloodstream infection (CRBSI) was 1.98/1000 catheter days and 2.17/1000 catheter days in the early- and late term groups, respectively. In the subgroup analysis, the detected causative pathogens of CRBSI did not differ between the two term groups; gram-positive cocci, gram-positive bacilli, and gram-negative bacilli were the causative pathogens in 68.9, 11.5, and 14.8% of the cases in the early term group and in 68.2, 11.4, and 18.2% of the cases in the late term group, respectively. In the multivariate analysis to determine the risk of CRBSI, only age was detected as an independent contributing factor; the indwelling catheter duration was detected as a marginal factor. A significant reduction in mechanical complications was associated with the use of ultrasound guidance.ConclusionsUltrasound-guided CVC insertion did not decrease the incidence of CRBSI. The only identified risk factor for CRBSI was age in our cohort. However, we found that the introduction of ultrasound-guided insertion triggered an overall change in safety management with or without the physicians’ intent.

GPU accelerated sequence alignment with traceback for GATK HaplotypeCaller

BackgroundPairwise sequence alignment is widely used in many biological tools and applications. Existing GPU accelerated implementations mainly focus on calculating optimal alignment score and omit identifying the optimal alignment itself. In GATK HaplotypeCaller (HC), the semi-global pairwise sequence alignment with traceback has so far been difficult to accelerate effectively on GPUs.ResultsWe first analyze the characteristics of the semi-global alignment with traceback in GATK HC and then propose a new algorithm that allows for retrieving the optimal alignment efficiently on GPUs. For the first stage, we choose intra-task parallelization model to calculate the position of the optimal alignment score and the backtracking matrix. Moreover, in the first stage, our GPU implementation also records the length of consecutive matches/mismatches in addition to lengths of consecutive insertions and deletions as in the CPU-based implementation. This helps efficiently retrieve the backtracking matrix to obtain the optimal alignment in the second stage.ConclusionsExperimental results show that our alignment kernel with traceback is up to 80x and 14.14x faster than its CPU counterpart with synthetic datasets and real datasets, respectively. When integrated into GATK HC (alongside a GPU accelerated pair-HMMs forward kernel), the overall acceleration is 2.3x faster than the baseline GATK HC implementation, and 1.34x faster than the GATK HC implementation with the integrated GPU-based pair-HMMs forward algorithm. Although the methods proposed in this paper is to improve the performance of GATK HC, they can also be used in other pairwise alignments and applications.

Dry eye after Lester Jones tube insertion for epiphora

ABSTRACTPurpose: To report the occurrence of dry eye after Lester Jones tube (LJT) insertion.Methods: Retrospective case series from a single unit. The dacrocystorhinostomy (DCR) was carried out using both endoscopic and external approachs; however, insertion of LJT used the same method as either a primary or secondary procedure. Dry eye as an outcome measure was only confirmed after three separate visits using the presence of both patient symptoms and dry eye signs with none preceding tube insertion.Results: Fifty-four patients underwent consecutive LJT insertion over a 5-year period. Mean age was 52.6 (range 25–73 years). The majority were female 39 (72%). Revision surgery was required in 15 (27%) with 3 or more occurring in 6 (11%). In total, 9 patients developed dry eyes (17%). Mean age was 60 (range 47–73) years, 5 females and 4 males. Four of the dry eye individuals had undergone primary LJT insertion and the remaining five received their first LJT 6–24 (mean 15) months post-DCR. Two dry eye patients had previously undergone LASIK and radiotherapy.Conclusion: A risk of dry eye following LJT placement is higher than the literature suggests. This should be considered and counseled, especially in those who have underlying pre-disposing factors. Ease of removal may be a desirable attribute in such cases.

Mechanism and Effect of Polar Styrenes on Scandium-Catalyzed Copolymerization with Ethylene.

Copolymerization of ethylene (E) and polar vinyl monomers remains a problem because E propagation is hindered. Herein, for the first time, we report the copolymerization of E and polar styrenes (SR ) by using an oxophilic scandium catalyst that exhibits higher turnover frequencies than both E and SR homopolymerizations when R is an electron-withdrawing group. This positive comonomer effect was elucidated through computing reaction profiles of E/SF copolymerization at the DFT (B3PW91) level of theory. It reveals that the secondary interaction between Sc3+ and phenyl of the last and penultimate inserted SF units leads to a decrease of the E insertion barrier, because the electron-withdrawing substituent enhances the electrophilicity of Sc3+ by an inductive effect mediated by the secondary interaction. After three consecutive insertions of the E units, the secondary interaction is lost and the SF insertion is kinetically preferred over the E insertion. This process is in line with the NMR spectrum analyses which show that the resultant copolymers mainly contain SR (E)x SR sequences where x≤3.

Computational Studies on the Selective Polymerization of Lactide Catalyzed by Bifunctional Yttrium NHC Catalyst

A theoretical investigation of the ring-opening polymerization (ROP) mechanism of rac-lactide (LA) with an yttrium complex featuring a N-heterocyclic carbine (NHC) tethered moiety is reported. It was found that the carbonyl of lactide is attacked by N(SiMe3)2 group rather than NHC species at the chain initiation step. The polymerization selectivity was further investigated via two consecutive insertions of lactide monomer molecules. The insertion of the second monomer in different assembly modes indicated that the steric interactions between the last enchained monomer unit and the incoming monomer together with the repulsion between the incoming monomer and the ligand framework are the primary factors determining the stereoselectivity. The interaction energy between the monomer and the metal center could also play an important role in the stereocontrol.

In situ DRIFTS study of CO coupling to dimethyl oxalate over structured Al-fiber@ns-AlOOH@Pd catalyst

Pd-catalyzed CO coupling to dimethyl oxalate (DMO) process has been commercialized but its reaction mechanism is still open for debate between COCOOCH3∗ and COOCH3∗ (∗, a surface site). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies were performed to clarify such controversy on a high-performance Al-fiber@ns-AlOOH@Pd catalyst. Intermediate species consisting of stretching vibrations of CO and CO, and rocking vibration of CH3 was indeed captured, which could be assigned to either COCOOCH3∗ or COOCH3∗. To make discrimination between COCOOCH3∗ and COOCH3∗, methyl oxalyl chloride (CH3OCOCOCl) and methyl chloroformate (CH3OCOCl) were employed to form COCOOCH3∗ and COOCH3∗ species on the catalyst surface for DRIFTS analyses. Interestingly, the characteristic bands of the as-observed intermediate species in the real reaction matched the obtained COCOOCH3∗ species from dissociative adsorption of CH3OCOCOCl. A double carbonylation reaction pathway was thus confirmed for the CO coupling to DMO, i.e., consecutive insertion of two CO molecules into OCH3∗ to form COCOOCH3∗ followed by combining OCH3∗ to yield DMO (CH3OCOCOOCH3).

Suppression of chain transfer in catalytic acrylate polymerization via rapid and selective secondary insertion.

In catalytic copolymerization, undesired chain transfer after incorporation of a polar vinyl monomer is a fundamental problem. We show an approach to overcome this problem by a fast consecutive insertion. The second double bond of acrylic anhydride rapidly inserts intramolecularly to regio- and stereoselectively form a cyclic repeat unit and a primary alkyl favorable for chain growth (>96%). This results in significantly enhanced copolymer molecular weights vs monofunctional acrylate monomers.

Redesign of process map to increase efficiency: Reducing procedure time in cervical cancer brachytherapy

To increase intraprocedural efficiency in the use of clinical resources and to decrease planning time for cervical cancer brachytherapy treatments through redesign of the procedure's process map. A multidisciplinary team identified all tasks and associated resources involved in cervical cancer brachytherapy in our institution and arranged them in a process map. A redesign of the treatment planning component of the process map was conducted with the goal of minimizing planning time. Planning time was measured on 20 consecutive insertions, of which 10 were performed with standard procedures and 10 with the redesigned process map, and results were compared. Statistical significance (p < 0.05) was measured with a two-tailed t test. Twelve tasks involved in cervical cancer brachytherapy treatments were identified. The process map showed that in standard procedures, the treatment planning tasks were performed sequentially. The process map was redesigned to specify that contouring and some planning tasks are performed concomitantly. Some quality assurance tasks were reorganized to minimize adverse effects of a possible error on procedure time. Test dry runs followed by live implementation confirmed the applicability of the new process map to clinical conditions. A 29% reduction in planning time (p < 0.01) was observed with the introduction of the redesigned process map. A process map for cervical cancer brachytherapy was generated. The treatment planning component of the process map was redesigned, resulting in a 29% decrease in planning time and a streamlining of the quality assurance process.

A method of assessing the effectiveness of the friction fit interface by measuring reverse torque

The connection between abutments and implants is fundamental to successful prosthetic rehabilitation, and the loosening or fracture of the parts are undesirable outcomes. The purpose of this study was to measure the reverse torque values of 2 different types of Morse taper implants. Ten Morse taper implants were used, with their respective abutments. They were divided into 2 groups (n = 5): Group DH, implant interface with a double hexagon and Group OI, octagonal implant interface. Each abutment received 2 consecutive insertion torques (32 Ncm) at a 10-minute interval and 1 reverse torque after 5 minutes. The data were analyzed with the Student t test (α= .05). The Student t test demonstrated no significant differences between the values of the insertion and removal torques of the 2 groups (Group DH, P= .22 and Group OI, P= .42) or the removal torque values of the groups (P= .12). The results suggest that the strength required to loosen the abutment screws as measured by reverse torque is similar for both a double hexagon interface (DH) and an octagonal interface (OI).

ChemInform Abstract: Synthesis of Functional ′Polyolefins′: State of the Art and Remaining Challenges

AbstractReview: 279 refs.

Heteroleptic Tin(II) Initiators for the Ring‐Opening (Co)Polymerization of Lactide and Trimethylene Carbonate: Mechanistic Insights from Experiments and Computations

The tin(II) complexes {LO(x)}Sn(X) ({LO(x)}(-) =aminophenolate ancillary) containing amido (1-4), chloro (5), or lactyl (6) coligands (X) promote the ring-opening polymerization (ROP) of cyclic esters. Complex 6, which models the first insertion of L-lactide, initiates the living ROP of L-LA on its own, but the amido derivatives 1-4 require the addition of alcohol to do so. Upon addition of one to ten equivalents of iPrOH, precatalysts 1-4 promote the ROP of trimethylene carbonate (TMC); yet, hardly any activity is observed if tert-butyl (R)-lactate is used instead of iPrOH. Strong inhibition of the reactivity of TMC is also detected for the simultaneous copolymerization of L-LA and TMC, or for the block copolymerization of TMC after that of L-LA. Experimental and computational data for the {LO(x)}Sn(OR)complexes (OR=lactyl or lactidyl) replicating the active species during the tin(II)-mediated ROP of L-LA demonstrate that the formation of a five-membered chelate is largely favored over that of an eight-membered one, and that it constitutes the resting state of the catalyst during this (co)polymerization. Comprehensive DFT calculations show that, out of the four possible monomer insertion sequences during simultaneous copolymerization of L-LA and TMC: 1) TMC then TMC, 2) TMC then L-LA, 3) L-LA then L-LA, and 4) L-LA then TMC, the first three are possible. By contrast, insertion of L-LA followed by that of TMC (i.e., insertion sequence 4) is endothermic by +1.1 kcal mol(-1), which compares unfavorably with consecutive insertions of two L-LA units (i.e., insertion sequence 3) (-10.2 kcal mol(-1)). The copolymerization of L-LA and TMC thus proceeds under thermodynamic control.