Test Method Research Articles

Development of a non-animal testing method using genetically engineered biosensors for assessing skin sensitizers

Development of a non-animal testing method using genetically engineered biosensors for assessing skin sensitizers

Transient temperature measurement of silicon carbide Schottky barrier diode based on thermal reflection.

In this article, we present a transient temperature detection device for silicon carbide (SiC) Schottky barrier diodes (SBDs) based on thermal reflection theory. We constructed a thermal reflection temperature measurement device based on a 530-nm green laser. This device is more suitable for transient temperature measurement of SiC SBDs than previous thermal reflection equipment. The accuracy of temperature measurement by our device was confirmed by comparison with the results of infrared thermal imaging. The high temporal resolution characteristics of the thermal reflection technology allowed the detection of millisecond-level transient temperature changes in SiC SBDs. In addition, we investigated the complementarity of transient temperature change curves during heating and cooling processes, as well as the reasons for the differences between these curves. Finally, we used the structural function method combined with the Bayesian deconvolution algorithm to obtain the thermal resistance along the heat flow path of the device and validated the results using an established thermal resistance testing method.

Continuous Wave Ultrasound Testing Techniques

Currently, the primary method employed for ultrasound inspection is based on sending and detecting ultrasound pulses. Typically, pulse-based methods are essentially time-domain back-reflection methods, and the time-of-flight is the main measured parameter. Recently, continuous-wave methods have been developed in the radar and the fiber-optics fields, which demonstrate significantly better spatial resolution, higher signal-to-noise ratio, and ability to detect reflecting objects at very short distances. It is proposed to use the same approach to develop continuous-wave ultrasound inspection systems. The two main differences between the proposed continuous-wave ultrasonic testing and the classical pulsed ultrasound inspection method are: (i) in the continuous-wave ultrasonic testing method, the transmitted and received signals overlap in the time domain, while in the pulsed ultrasound inspection method the transmitted and received signals are separated in the time; and (ii) in the pulsed ultrasound inspection method the most important parameter is the time delay between the transmitted and received signals, while in the continuous-wave ultrasonic testing method the most informative parameters are the frequency and phase changes in the received signal in respect to modulated transmitted signal. This allows for additional flexibility in the continuous-wave ultrasonic measurements, through control of the frequency modulation. Also, the continuous-wave ultrasonic method potentially offers improved detection range and resolution; improved signal-to-noise ratio due to better energy efficiency and easier filtering; and reduced requirements on the voltage applied to the transducer, which in turn allows the use of simplified low-cost electronics. The theoretical basis of several continuous-wave ultrasound inspection technique is explained, and their advantages and limitations are discussed. Implementation of several prototype continuous-wave ultrasound testing systems is presented. Examples of the use of the systems for non-destructive testing are described.

Which one is more accurate, BILOG or R program? (a comparison for score test equating)

Evaluation may be carried out using different tests that are not necessarily parallel. Students with lower abilities may get higher scores while those with higher abilities get lower scores. Measurement errors caused by this condition require test equating. Several computer programs, including Bilog and the R program, can be used for test equating. Each program has a different level of accuracy, and the accuracy of the equating results will affect the standard errors of equating. This study aimed to find out the most accurate equating test method and the accuracy of the estimated BILOG and R program. This research used two sets of tests with equivalent group designs. The determination of the most accurate equating method was based on the root mean square deviation (RMSD) value. Equating test packages, A to package B with BILOG program estimation on the mean and Sigma method resulted in RMSD value of 0.320. In the mean and mean method, RMSD value is 0.250. Meanwhile, equating package A to package B using R program on the mean and sigma resulted in RMSD value of 0.300, and the mean and mean method with the RMSD value is 0.272. The mean and mean yield RMSD values smaller than the mean and sigma methods. Therefore, the mean and mean method is more accurate and applicable. Moreover, the estimation results of the BILOG program are more accurate and can be used in test equating.

Inline Monitoring of continous Ultrasonic Welding Processes of Thermoplastic Composites via a custom polyCMUT based Ultrasound Array

Ultrasonic welding (UW) of thermoplastic composites (TCs) is an emerging technology in the field of composite joining techniques in the aerospace sector. Through a mechanical oscillator, ultrasound at a frequency of 20kHz is induced into the material via a welding horn, where microscopic friction and damping effects melt the thermoplastic. Under further pressure the weld area cools down, permanently joining both parts together. Like all joining processes in the aerospace industry the resulting joints need to be tested for their quality and structural integrity. The traditional testing method using water-coupled ultrasound includes extra steps. This process could be considerably improved by assessing the quality of the weld directly after or even during the welding process, allowing for immediate rework or discard of the parts in question. Ultrasound is still the best solution for this quality assessment, being inexpensive, well understood, and able to create B-Mode images, allowing a look into the cross-section of the weld. However, there are several major problems: To increase the system complexity as little as possible it is necessary to attach the ultrasound unit next to the welding equipment, and as close to the welding horn and compactor as possible to save space and keep the end- effector manoeuvrable. This brings problems for classic piezoelectric ultrasonic arrays: The low welding frequency and its resonance modes reach into the lower resonance modes of the piezoelectric sensors leading to immense noise, hiding any potential echo from the welding zone. Classic piezoelectric crystals are also very brittle and can suffer damage from sustained exposure to this violent environment. The authors present a novel solution: a custom-made polymer-based capacitive micromachined ultrasonic transducer array (polyCMUT). polyCMUTs are tiny drums with two electrodes. One on the bottom and the other suspended over a cavity sandwiched between two layers of polymers. By applying a DC-bias an electrical field is created and the membrane is set under tension. If then an AC voltage is applied, the strength of the electric field decreases, allowing the membrane to snap back into its original position. If done at the resonance frequency of the membrane, a strong ultrasonic signal is created. To receive this signal the polyCMUT is charged with a DC-bias, allowing it to receive the echo of the transmitted signal by measuring the changing capacitance. Not only is the polymer robust and inexpensive to fabricate, the general architecture of CMUTs also allows a design where the first mode of resonance is the actual mode the CMUT is operating in. By designing for a resonance frequency over 5 MHz all noise from the initial welding process is ignored, leading to a working pulse echo imaging system. The array is then mounted onto a PEEK block attached to the compactor unit of the welding end-effector. This publication is intended to present initial results, the design process of the custom array and the tests leading there.

Principle of the electromagnetic testing based on the varied frequency domain and its realization

With the development of modern industry, the types and quantities of industrial equipment are increasing. In the long-term production process, various failure modes such as corrosion and cracks will occur, therefore the workload of inspection will increase dramatically. It is extremely urgent to study the combined non-destructive testing (NDT) technology and develop corresponding multi-functional instruments to achieve rapid inspection. In this paper, an electromagnetic testing principle based on the varied frequency domain is proposed. In the first place, spatial uniformity and spatial periodic static fields are generated by the arrangement of the permanent magnetizers, these static fields are fields with different spatial frequencies. In the second place, dynamic fields with different frequencies are generated by different frequencies excitations. Under the time-space electromagnetic field coupling, a new combined electromagnetic testing principle of magnetic flux leakage (MFL), guided wave (GW) and electromagnetic acoustic transducer (EMAT) is proposed. The MFL testing method can be realized based on the uniform static field, GW based on the interaction of spatial periodic static field and low frequency dynamic field, while EMAT based on the combination of uniform static field and high frequency dynamic field. According to the above principle, a multi-functional instrument is developed, which includes a medium-low frequency excitation unit for GW, a high frequency excitation unit for EMAT, corresponding receiving amplifiers for GW/EMAT/MFL, and USB-based data transmitters. Finally, the relevant performance tests are carried out, which laid the foundation for field application.

Air-coupled ultrasonic inspection of resin materials using single-probe vertical reflection method

Air-coupled ultrasonic inspection is a noncontact and convenient nondestructive testing method. However, its vertical reflection method using a single probe (i.e., pulse-echo mode) is known to be difficult to achieve, even though it is frequently used inspection mode in conventional contact or water immersion ultrasonic testing. This is because the reflectivity of ultrasonic waves at the boundary between air and the surface of inspection object is enormous, and faint signals received after transmitting into the object are difficult to detect. In this study, in order to achieve the air-coupled ultrasonic single-probe reflection method, transmitting chirp signals (waves with a linearly frequency modulation) with an appropriate window function and applying a pulse compression technique (a cross-correlation process between the received signal and a reference chirp signal) was examined, and its effectiveness was investigated through experiments for polystyrene specimens. Experimental results showed that the proposed method was effective in detecting faint reflection signals after propagating through the specimens, and that the difference in plate thickness could be detected by observing the change of the signal-receiving period of multiple reflection signals between the top and bottom surfaces of the specimens. These results demonstrate the feasibility of nondestructive testing using the air-coupled ultrasonic vertical reflection method and could show an important step toward its future practical applications.

Visual midline gauge validity and repeatability: Comparison to a current clinical method.

Visual midline shifts are thought to occur post-stroke and be a risk factor for falls. This study investigates a new method for quantifying visual midline shifts, a first step toward developing greater understanding of visual midline shift. This study standardized the parameters of a novel visual midline gauge, compared the results with the current clinical method, and presents normative data and repeatability of both methods. Ninety-three participants without neurological or ocular problems were recruited in Canada and Hong Kong. In experiment 1, horizontal and vertical visual midlines were measured using the gauge for two speeds and two repositioning methods. In experiment 2, visual midline was measured for three distances using a target speed and repositioning method chosen based on the first experiment. Visual midlines were also measured using the current clinical method during both visits. There were no significant effects of age, speed, study location, or repositioning method on visual midline positions (all p>0.05). For the horizontal direction, measurements at 25 cm were different from those at 50 (p=0.03) and 100 cm (p=0.001). For the vertical direction, there was no such effect. The measurements were found to be repeatable to within approximately 3°. In both visits, there were significant correlations between measurements using the visual midline gauge and the clinical method for the vertical direction (all p<.001) but not for the horizontal direction (all p>0.05). The measurement of visual midline is tolerant of differences in target speed, testing method, and age of the participants, and the visual midline gauge measurements are repeatable.

An automatic measurement method for the response of Caenorhabditis elegans to chemicals.

Caenorhabditis elegans is a widely used model animal. Chemotaxis assay is one of the experiments that study the effects of different chemicals on nematodes. It is mainly used to study the effects of different chemicals on the perception behavior of nematodes. By conducting this experiment, not only can the neurotoxicity of chemicals be reflected, but also the impact of chemicals on physiological functions regulated by the nervous system, such as nematode feeding behavior and basic motor ability. The experiment of detecting the response of nematode to chemicals is also a common method of chemical toxicity testing based on nematode models. In the analysis of worm tendency behavior, manual operations are generally used. Manually processing a large number of worms under a microscope is very time-consuming and labor-intensive. The current quantitative methods for nematode chemotaxis experiments are not only time-consuming and labor-intensive, but also biased in experimental results due to differences in judgment standards among experimenters. The automatic and efficient quantification method for nematode chemotaxis experiments is a very important technical difficulty in the field of nematode experiments. Here, we have designed an automatic quantification method for nematode chemotaxis experiments by incorporating image acquisition and processing techniques into the nematode experiment. The experimental results show that the Pearson correlation coefficient between manual and automatic counting results is 0.978. This proves the effectiveness of our method. Applying the automatic measurement method to replace manual counting by the experimenter can improve work efficiency, and reduce errors in human counting operations.

Exploring the Resistance of Pigmented Rice to Brown Planthopper (Nilaparvata lugens Stål) by Phenotypic and Genotypic Analyses

Developing new pigmented rice varieties that meet consumers' preferences requires addressing resistance to brown planthopper (BPH), a highly destructive insect pest of rice. To effectively manage this pest, it is essential to explore BPH resistance genes from rice germplasms and incorporate them into elite varieties. The objective of this study was to identify the source of resistance among local and improved pigmented rice varieties in Indonesia against field BPH. Furthermore, the study aimed to characterize their genetic diversity using molecular markers associated with Bph genes and functional markers for these genes. Eighty-eight local varieties from the Indonesian Agricultural Gene Bank, collected across 18 provinces between 1971 and 2019, and four improved varieties, were evaluated using the standard seed box screening test method. Among these entries, 6 local accessions and 1 improved variety exhibited moderate resistance. Genetic analysis of these entries and three randomly selected susceptible entries using 12 SSR and InDel markers associated with Bph gene loci showed that the moderately resistant entries had higher allele numbers (11 to 13) compared to the susceptible entries (4 to 7). These markers could distinguish the resistant group from the susceptible ones in cluster analysis. Genotyping using functional markers further showed that the moderately resistant entries had 2 to 4 combinations of Bph genes. In contrast, the susceptible entries contained neither Bph genes nor only one gene. Local accessions with a 2 to 4 Bph gene combination can be donors of BPH resistance in improving pigmented rice varieties.

Determination of Poisson’s ratio of coal gangue-based shotcrete materials using a non-contact test method

ABSTRACT Preparing shotcrete materials using coal gangue is an effective method of disposal and use of gangue solid waste, while testing the Poisson’s ratio of coal gangue-based shotcrete materials (CGSM) is an important step in evaluating the mechanical properties of such materials. Therefore, to study the evolution of the Poisson’s ratio of CGSM under different influencing factors, detailed test schemes and procedures were designed based on the non-contact test method of Poisson’s ratio. The accuracy of the non-contact test method is verified. In addition, changes in the Poisson’s ratio of CGSM under different factors were studied. Results show that the Poisson’s ratio of CGSM tends to reduce with prolonged curing. When the particle sizes of coal gangue are 0 ~ 2.5 and 2.5 ~ 5 mm, fine particles can fill interstitial voids in shotcrete materials. As the mass concentration and cement content increase, the Poisson’s ratio of CGSM gradually decreases; as the sand content rises, the Poisson’s ratio gradually increases.

Verification of the analytical performance of the serum magnesium assay on Abbott Architect ci8200

Magnesium is recognized as the fourth most important cation in the body and the second most abundant intracellular cation, following potassium. Its physiological significance lies in its capacity to form complexes with crucial intracellular anionic ligands, notably ATP, and its ability to compete with calcium for specific binding sites on proteins and cell membranes. Over 300 enzyme reactions rely on magnesium. The concentration of free magnesium within cells determines the magnesium content of these enzymes. Magnesium influences myocardial contraction and the electrical activity of myocardial cells, as well as the specialized conduction systems of the fetus, by modulating the transmembrane movements of ions like sodium, potassium, and calcium. Furthermore, magnesium can affect the contractility of vascular smooth muscle, and alterations in intracellular magnesium levels may impact cell proliferation or contraction. Magnesium is involved in nucleic acid and protein metabolism, intermediary metabolism, energy production, and consumption reactions, and it plays specific roles in various physiological systems such as the neuromuscular and cardiovascular systems. Our research aims to assess the analytical accuracy of the serum magnesium assay method utilizing an Abbott kit on the Architect ci8200 automated system in the biochemistry laboratory of Mohammed VI University Hospital of Oujda. The evaluation of the kit's analytical accuracy was conducted within the flexible scope A by conducting a performance analysis on the Architect ci8200. We examined repeatability, reproducibility, measurement imprecision, and compared results between two Architect ci8200 instruments. All findings align with the acceptability criteria recommended by the supplier and the Valtec protocol of the Société Française de Biologie Clinique (SFBC), indicating overall satisfactory outcomes for the study. The Architect ci8200 automated system demonstrated satisfactory analytical performance for reliably determining serum magnesium levels. Method verification in medical laboratories is essential to guarantee the accuracy, precision, and reliability of test results. Verification entails confirming that the test method used is suitable for its intended purpose, yields result consistent with the claimed performance characteristics, and meets the laboratory's quality control and quality assurance standards.

A collaborative review of the microsatellite instability/deficient mismatch repair phenotype in patients with upper tract urothelial carcinoma.

To perform a collaborative review of the literature exploring the microsatellite instability/deficient mismatch repair (MSI/dMMR) phenotype in patients with upper tract urothelial carcinoma (UTUC). A collaborative review of the literature available on Medline was conducted by the Cancer Committee of the French Association of Urology to report studies describing the genetic mechanisms, investigation, prevalence and impact of the MSI/dMMR phenotype in UTUC patients. The predominant genetic mechanism leading to the MSI/dMMR phenotype in UTUC patients is related to the constitutional mutation of one allele of the MMR genes MLH1, MSH2, MSH6 and PMS2 within Lynch syndrome. Indications for its investigation currently remain limited to patients with a clinical suspicion for sporadic UTUC to refer only those with a positive testing for germline DNA sequencing to screen for this syndrome. With regard to technical aspects, despite the interest of MSIsensor, only PCR and immunohistochemistry are routinely used to somatically investigate the MSI and dMMR phenotypes, respectively. The prevalence of the MSI/dMMR phenotype in UTUC patients ranges from 1.7% to 57%, depending on the study population, investigation method and definition of a positive test. Younger age and a more balanced male to female ratio at initial diagnosis are the main specific clinical characteristics of UTUC patients with an MSI/dMMR phenotype. Despite the conflicting results available in the literature, these patients may have a better prognosis, potentially related to more favourable pathological features. Finally, they may also have lower sensitivity to chemotherapy but greater sensitivity to immunotherapy. Our collaborative review summarises the available data from published studies exploring the MSI/dMMR phenotype in UTUC patients, the majority of which are limited by a low level of evidence.

Coupling the PROSAIL Model and Machine Learning Approach for Canopy Parameter Estimation of Moso Bamboo Forests from UAV Hyperspectral Data

Parameters such as the leaf area index (LAI), canopy chlorophyll content (CCH), and canopy carotenoid content (CCA) are important indicators for evaluating the ecological functions of forests. Currently, rapidly developing unmanned aerial vehicles (UAV) equipped with hyperspectral technology provide advanced technical means for the real-time dynamic acquisition of regional vegetation canopy parameters. In this study, a hyperspectral sensor mounted on a UAV was used to acquire the data in the study area, and the canopy parameter estimation model of moso bamboo forests (MBF) was developed by combining the PROSAIL radiative transfer model and the machine learning regression algorithm (MLRA), inverted the canopy parameters such as LAI, CCH, and CCA. The method first utilized the extended Fourier amplitude sensitivity test (EFAST) method to optimize the global sensitivity analysis and parameters of the PROSAIL model, and the successive projections algorithm (SPA) was used to screen the characteristic wavebands for the inversion of MBF canopy parameter inversion. Then, the optimized PROSAIL model was used to construct the ‘LAI-CCH-CCA-canopy reflectance’ simulation dataset for the MBF; multilayer perceptron regressor (MLPR), extra tree regressor (ETR), and extreme gradient boosting regressor (XGBR) employed used to construct PROSAIL_MLPR, PROSAIL_ETR, and PROSAIL_XGBR, respectively, as the three hybrid models. Finally, the best hybrid model was selected and used to invert the spatial distribution of the MBF canopy parameters. The following results were obtained: Waveband sensitivity analysis reveals 400–490 and 710–1000 nm as critical for LAI, 540–650 nm for chlorophyll, and 490–540 nm for carotenoids. SPA narrows down the feature bands to 43 for LAI, 19 for CCH, and 9 for CCA. The three constructed hybrid models were able to achieve high-precision inversion of the three parameters of the MBF, the model fitting accuracy of PROSAIL_MLRA reached more than 95%, with lower RMSE values, and the PROSAIL_XGBR model yielded the best fitting results. Our study provides a novel method for the inversion of forest canopy parameters based on UAV hyperspectral data.

Observing and Modeling the Wear Process of Heterogeneous Interface.

Understanding and controlling the wear process of heterogeneous interfaces between soft and hard phases is crucial for designing and fabricating materials, such as improving the wear resistance of particle reinforced metal matrix composites and the accuracy and efficiency of chemical mechanical polishing. However, the wear process can be hardly observed, as interfaces are buried under the surface. Here, we proposed a nanowear test method by combining focused ion beam cutting to expose interfaces, atomic force microscopy to rub against interfaces, and scanning electron microscope to characterize the interface damage. Using this method, three typical wear forms had been observed in Al/SiC composite, i.e., merely matrix wear, particle fracture, and particle pullout. A theoretical model was proposed that revealed that the increasing interfacial friction would induce particle fracture or pullout, depending on the particle edge angle and tip edge angle. This work sheds light on wear control in composites and nanofabrication.

A modular strategy for the testing and assessment of non-genotoxic carcinogens.

A modular strategy is described for thetesting and assessment (MoSt) of non-genotoxic carcinogenicity (NGTxC) that is suitable for regulatory applications. It utilizes and builds upon work conducted by the OECD expert group on NGTxC. The approach integrates relevant test methods from the molecular- to cellular- and further to tissue level, many of which have been recently reviewed. Six progressive modules are included in the strategy. Advice is provided for the iterative selection of the next appropriate test method within each step of the strategy. Assessment is completed by a weight of evidence conclusion, which integrates the different streams of modular information. The assessment method gives higher weight to findings that are mechanistically linked with biological relevance to carcinogenesis. With a focus on EU-REACH, and pending upon successful test method validation and acceptance, this will also enable the MoSt for NGTxC to be applied for regulatory purposes across different regulatory jurisdictions.

Detection Method for Gene Doping in a Mouse Model Expressing Human Erythropoietin from Adeno-Associated Virus Vector-9.

With the rapid development of gene therapy technology in recent years, its abuse as a method of sports doping in athletics has become a concern. However, there is still room for improvement in gene-doping testing methods, and a robust animal model needs to be developed. Therefore, the purposes of this study were to establish a model of gene doping using recombinant adeno-associated virus vector-9, including the human erythropoietin gene (rAAV9-hEPO), and to establish a relevant testing method. First, it was attempted to establish the model using rAAV9-hEPO on mice. The results showed a significant increase in erythrocyte volume accompanied by an increase in spleen weight, confirming the validity of the model. Next, we attempted to detect proof of gene doping by targeting DNA and RNA. Direct proof of gene doping was detected using a TaqMan-qPCR assay with certain primers/probes. In addition, some indirect proof was identified in RNAs through the combination of a TB Green qPCR assay with RNA sequencing. Taken together, these results could provide the foundation for an effective test for gene doping in human athletes in the future.

Uji Kerentanan Aedes aegypti terhadap Malation, Permetrin, dan Bendiokarb di Kelurahan Tangkerang Timur Kecamatan Tenayan Raya, Pekanbaru

Insecticide resistant of Aedes aegypti populations is one of the main problems in controlling dengue hemorrhagic fever vectors because it will produce resistant offspring. This study aimed to determine the insecticide susceptibilty status of Ae. aegypti to 5% malathion, 0,75% permethrin, and 0,1% bendiocarb in Tangkerang Timur Village, Tenayan Raya District, Pekanbaru. This study is a descriptive observational study with a cross-sectional design. The resistance test method in this study was the World Health Organization (WHO) susceptibility test method with impregnated paper (5% malation, 0,75% permethrin, and 0,1% bendiocarb). The larval that were reared into adult mosquitoes were collected from 100 houses in Tangkerang Timur Village. Total adult mosquitoes aged 3-5 days tested in this study were 100 mosquitoes. The test mosquitoes were exposed to impregnated paper for 1 hour and the number of knock down mosquitoes was counted. Mosquito mortality was counted after 24 hours. The results of the susceptibility test in this study showed the mortality of Ae. aegypti to 5% malathion, 0,75% permethrin, and 0,1% bendiocarb were 100%, 85%, and 3.75%. The results of this study indicated that Ae. Aegypti has been resistant to 0,75% permethrin and 0,1% bendiocarb and susceptible to 5% malathion.

Outcomes of 23 patients diagnosed with New Delhi metallo-beta-lactamase (NDM)-producing Klebsiella pneumoniae infection treated with ceftazidime/avibactam and aztreonam at a single center in Poland.

Amongst all etiologic hospital-acquired infection factors, K. pneumoniae strains producing New Delhi metallo-β-lactamase (KP-NDM) belong to pathogens with the most effective antibiotic resistance mechanisms. Clinical guidelines recommend using ceftazidime/avibactam with aztreonam (CZA + AT) as the preferred option for NDM-producing Enterobacterales. However, the number of observations on such treatment regimen is limited. This retrospective study reports the clinical and microbiological outcomes of 23 patients with KP-NDM hospital-acquired infection treated with CZA + AT at a single center in Poland. The isolates were derived from the urine, lungs, blood, peritoneal cavity, wounds, and peritonsillar abscess. In microbiological analysis, mass spectrometry for pathogen identification, polymerase chain reaction, or an immunochromatographic assay for detection of carbapenemase, as well as VITEK-2 system, broth microdilution, and microdilution in agar method for antimicrobial susceptibility tests were used, depending of the pathogens' nature. CZA was administered intravenously (IV) at 2.5g every eight hours in patients with normal kidney function, and aztreonam was administered at 2g every eight hours IV. Such dosage was modified when renal function was reduced. KP-NDM was eradicated in all cases. Four patients (17.4%) died: three of them had a neoplastic disease, and one - a COVID-19 infection. The combination of CZA + AT is a safe and effective therapy for infections caused by KP-NDM, both at the clinical and microbiological levels. The synergistic action of all compounds resulted in a good agreement between the clinical efficacy of CZA + AT and the results of in vitro susceptibility testing.

Analysis of the efficacy of left subclavian artery laser in situ fenestration combined with hybrid arch debranching surgery for aortic arch reconstruction in patients with Stanford type A aortic dissection

Objective: To observe the short-and mid-term efficacy of left subclavian artery(LSA) laser in situ fenestration combined with arch debranching surgery for aortic arch reconstruction in patients with Stanford type A aortic dissection aged 60 years and above. Methods: This is a retrospective cohort study. A total of 41 Stanford type A aortic dissection patients aged 60 years and above who received combined surgery in Department of Endovascular Surgery, the First Affiliated Hospital of Zhengzhou University from January 2018 to December 2020 were retrospectively analyzed. There were 25 males and 16 females, aged (67.3±5.9)years(range: 60 to 75 years). Among them, 19 patients underwent LSA laser in situ fenestration combined with arch debranching surgery(combined surgery group) and 22 patients underwent hybrid aortic arch debranching surgery(non-combined surgery group). Independent sample t test, χ2 test and Fisher exact probability method were used to compare the clinical characteristics of the two groups. Kaplan-Meier method was used for survival analysis, and the 5-year survival rate of the two groups was compared by Log-rank test. Results: Body mass index in the combined operation group was significantly higher than that in the non-combined operation group ((27.1±1.6)kg/m2 vs.(26.9±1.9)kg/m2; t=2.766,P=0.006), and the difference was statistically significant. There was no statistical significance in the comparison of other general data (all P>0.05). The operation time ((320.9±21.7) minutes vs. (326.7±22.5)minutes; t=14.838, P<0.01)) and LSA reconstruction time ((32.6±3.2)minutes vs. (44.7±6.0)minutes; t=46.913, P<0.01) in the combined operation group were significantly shortened, and the difference was statistically significant. The rate of LSA reconstruction in the combined operation group (100% vs. 72.7%; P=0.023) was significantly higher than that in the non-combined operation group, and the difference was statistically significant. There were no significant differences in the incidence of pulmonary infection, unplanned second operation, continuous renal replacement therapy, neurological complications and the in-hospital mortality between the two groups. Compared with the non-combined surgery group, the total complication rate related to LSA reconstruction was significantly lower in the combined surgery group (0 vs. 27.3%; P=0.023). Kaplan-Meier survival analysis showed that there was no difference in 5-year survival rate between the combined operation group and the non-combined operation group (84.2% vs 77.3%; χ2=0.310, P=0.578). Conclusion: Laser in situ fenestration of the LSA combined with arch debranching surgery to reconstruct the aortic arch can significantly shorten the operation and LSA reconstruction time in patients with Stanford type A aortic dissection, improve the success rate of LSA reconstruction, and reduce the occurrence rate of LSA reconstruction complications.