Theoretical Study of the Temperature- and Pressure-Dependent Rate Constants for Nine Reactions between COn (n = 0-4), Om (m = 1-3), C2O, and C3O2 during the Radiolysis of Carbon Dioxide.

We investigate the reaction pathways of nine important CO2-related reactions using the revDSD-PBEP86-D3(BJ)/jun-cc-pV(T+d)Z level and simultaneously employ an accurate composite method (jun-Cheap) based on coupled-cluster (CC) theory. Subsequently, the Rice-Ramsperger-Kassel-Marcus/master equation (RRKM/ME) is solved to calculate the temperature- and pressure-dependent rate constants. This work investigates reactions involving transition states that have been overlooked in previous literature, including the dissociation of singlet-state C3O2, the triple channel formation of C2O + CO to form C3O2, and the formation of O3 + CO. The results show that CO3 is highly prone to dissociation at high temperatures. Finally, the kinetic data show that over a wide temperature range, our calculations are consistent with previous experimental measurements. The majority of the reaction rate constants studied exhibit significant pressure dependence, while the O3 + CO reaction is pressure-independent at low temperatures. These results are instrumental in the development of detailed kinetic models for the CO2 radiolysis reaction network.

Boosting the Capacitor Performance of the Metal Organic Frameworks Derived V2O5 Nanoflower by Cu Doping.

Due to its ultrahigh theoretical capacitance, vanadium pentoxide (V2O5) is considered to be a valid candidate for advanced supercapacitors. However, because of the low electron/electrolyte transfer rate, the capacitive performance still remains to be improved. In this report, Cu doping is adopted to improve the capacitive performance by a two-steps strategy consisting of microwave-assisted solvothermal and postannealing treatments. The electrochemical results indicate that the Cu doping was beneficial for improving the specific capacitance, extending the potential window, and improving the rate ability and long-term stability of V2O5. Furthermore, the mechanism for the performance improvement is explained in detail by combining theoretical calculation and experiments. The results indicated that, compared with that of undoped V2O5, the larger interplanar spacing, better electrical conductivity, a larger proportion of V3+/V4+, and more abundant oxygen vacancies result in an improved capacitive performance. Our proposed Cu-doped V2O5 (Cu-V2O5) can be used as both a positive electrode and a negative electrode for the assembly of the symmetric supercapacitor, which can be used as an energy storage device for light emitting diode lamps.

LC-MS/MS methods for simultaneous determination of youkenafil and its metabolite M1 in human seminal plasma and plasma: Application to evaluate the acute effect of youkenafil on semen quality and its pharmacokinetics in human.

Youkenafil is a novel Phosphodiesterase type 5 inhibitor used for treating erectile dysfunction. N-desethyl compound of youkenafil (M1) is its main active metabolite. In this study, two methods were developed and validated for the simultaneous determination of youkenafil and M1 by HPLC-MS/MS in human matrices including seminal plasma and plasma, in which the multiple reaction monitoring and electrospray ionization in positive mode were adopted, and the deuterated youkenafil (youkenafil-d5) was selected as the internal standard. The collected semen sample was kept at room temperature for approximately 30 min until fully liquefied. The volume of the liquefied semen was measured and then divided into two parts. One part was centrifuged to obtain the seminal plasma for the content detection of youkenafil and M1, while the other part was used for routine semen analysis. The chromatographic separation was accomplished with the column of Poroshell 120 EC-C18 (5 × 2.1 mm, 2.7 µm, Agilent). Protein precipitation with methanol was used for the pretreatment of seminal plasma and plasma. The intra-run and inter-run precisions were less than 6.4 % (relative standard deviation) and accuracies were all within -4.7 %-6.8 % (relative error) in both matrices. All other validated bioanalytical parameters were within the acceptance criteria set by the FDA. The methods were successfully applied to different clinical studies of youkenafil. In the clinical study of the acute effect of youkenafil on semen quality in healthy males, the content of youkenafil in seminal plasma was extremely low. Concentrations of youkenafil and M1 in seminal plasma were lower than those in plasma, at 20.7 % and 4.49 % of the plasma concentration, respectively. There was no significant acute effect of youkenafil on semen quality. In the pharmacokinetic study of youkenafil after single dose-escalation administration, the exposure to youkenafil and M1 was non-linear with the dose in the range of 100-400 mg.

Determination of diethylstilbestrol in environmental water based on electrochemical senser modified with vanadium based metal organic framework material composite.

In this research, the MIL-47/ACET/Nafion/GCE electrochemical senser for the determination of diethylstilbestrol (DES) was prepared with vanadyl sulfate (VOSO4·nH2O) and terephthalic acid (H2BDC) as the main raw materials, compounded with acetylene black (ACET) and perfluorosulfonic acid polymer (Nafion). The compound DES belongs to the category of estrogens, and prolonged exposure to the environment can have detrimental effects on the physiological functioning of both humans and animals. Due to the strong DES enrichment performance of MIL-47(V-MOFs) with large specific surface area, in addition to the excellent conductivity and electrocatalysis of composite materials, this modified senser had good electrochemical response to DES. With differential pulse voltammetry, in optimum condition of 0.1 M NaH2PO4-Na2HPO4at pH = 7.0, potential interval of -1.0 to 1.0 V, enrichment time of 120 s and enrichment potential of 0.2 V, there was a good linear relationship between peak current and the concentration of DES over the range of 0.1 and 50µM, and the limit of detection was 0.008µM. The sensor accurately detected DES in actual water samples, with recovery rates ranging from 89.21% to 105.3%. The electrochemical sensor was simple to prepare and had practical significance for the detection of DES in water. The research results of the sensor provide another alternative analytical means for the sensitive detection of DES in the environment, which is important for maintaining public health.

Comparative efficacy of concurrent training types on lower limb strength and muscular hypertrophy: A systematic review and network meta-analysis.

Objective: This study aims to compare, through quantitative analysis, the effectiveness of different endurance training types on increasing lower limb strength and muscle cross-sectional area (MCSA) in concurrent training. Methods: This systematic literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) [PROSPERO ID: CRD42023396886]. Web of Science, SportDiscuss, Pubmed, Cochrane, and Scopus were systematically searched from their inception date to October 20, 2023. Results: A total of 40 studies (841 participants) were included in this meta-analysis. MCSA analysis showed that, compared to resistance training alone, concurrent high-intensity interval running training and resistance training and concurrent moderate-intensity continuous cycling training and resistance training were more effective (SMD = 0.15, 95% CI = -0.46 to 0.76, and SMD = 0.07, 95% CI = -0.24 to 0.38 respectively), while other modalities of concurrent training not. Lower body maximal strength analysis showed that all modalities of concurrent training were inferior to resistance training alone, but concurrent high-intensity interval training and resistance training showed an advantage in four different concurrent training modalities (SMD = -0.08, 95% CI = -0.25 to 0.08). For explosive strength, only concurrent high-intensity interval training and resistance training was superior to resistance training (SMD = 0.06, 95% CI = -0.21 to 0.33). Conclusion: Different endurance training types have an impact on the effectiveness of concurrent training, particularly on lower limb strength. Adopting high-intensity interval running as the endurance training type in concurrent training can effectively minimize the adverse effects on lower limb strength and MCSA.

Selectfluor-Mediated Electrophilic Annulation of 2-Alkynyl Biaryls with Diorganyl Diselenides.

A general and efficient method for the synthesis of various selanyl phenanthrenes/polycyclic heteroaromatics through the electrophilic annulation of 2-alkynyl biaryls with diorganyl diselenides under metal-free and mild conditions was established. The sulfanyl phenanthrene was also obtained in moderate yields.

Modifying a D-A-π-A-D HTM system for higher hole mobility by the meta-substitution strategy to weaken the electron-donating ability of the donor unit: a DFT study.

Tuning the electron-donating ability (EDA) of the donor units of hole transporting materials (HTMs) is an efficient strategy to modulate the optoelectronic properties of HTMs. Based on this strategy, we first theoretically investigated the effects of the EDA of donor units on D-A-π-A-D architectural HTMs. The results show that the enhanced EDA of the donor unit leads to larger hole reorganization energy and poorer molecular stability of HTMs. In contrast, meta-substitution of side groups is an effective strategy to reduce the EDA of the donor unit. We found that the application of the meta-substitution strategy in the D-A-π-A-D system not only successfully improves the molecular stability, but also achieves higher hole mobility by promoting the electronic coupling between the molecular dimers and decreasing the hole reorganization energies simultaneously. Studies on interfacial properties indicate that intermolecular coupling also synergistically enhances the interfacial charge extraction performance and reduces carrier recombination. In conclusion, by utilizing the meta-substitution strategy to reduce the EDA of donor units on D-A-π-A-D architectural HTMs, we successfully designed four superior performance HTMs mD1, mD2, mD3, and mD4.

Generating Topologically Consistent BIM Models of Utility Tunnels from Point Clouds.

The development and utilization of urban underground space is an important way to solve the "great urban disease". As one of the most important types of urban underground foundations, utility tunnels have become increasingly popular in municipal construction. The investigation of utility tunnels is a general task and three-dimensional laser scanning technology has played a significant role in surveying and data acquisition. However, three-dimensional laser scanning technology suffers from noise and occlusion in narrow congested utility tunnel spaces, and the acquired point clouds are imperfect; hence, errors and redundancies are introduced in the extracted geometric elements. The topology of reconstructed BIM objects cannot be ensured. Therefore, in this study, a hierarchical segmentation method for point clouds and a topology reconstruction method for building information model (BIM) objects in utility tunnels are proposed. The point cloud is segmented into facades, planes, and pipelines hierarchically. An improved mean-shift algorithm is proposed to extract wall line features and a local symmetry-based medial axis extraction algorithm is proposed to extract pipelines from point clouds. A topology reconstruction method that searches for the neighbor information of wall and pipeline centerlines and establishes collinear, perpendicular, and intersecting situations is used to reconstruct a topologically consistent 3D model of a utility tunnel. An experiment on the Guangzhou's Nansha District dataset successfully reconstructed 24 BIM wall objects and 12 pipelines within the utility tunnel, verifying the efficiency of the method.

Quantifying the spatial spillover effects of non-pharmaceutical interventions on pandemic risk.

BACKGROUND: Non-pharmaceutical interventions (NPIs) implemented in one place can affect neighboring regions by influencing people's behavior. However, existing epidemic models for NPIs evaluation rarely consider such spatial spillover effects, which may lead to a biased assessment of policy effects. METHODS: Using the US state-level mobility and policy data from January 6 to August 2, 2020, we develop a quantitative framework that includes both a panel spatial econometric model and an S-SEIR (Spillover-Susceptible-Exposed-Infected-Recovered) model to quantify the spatial spillover effects of NPIs on human mobility and COVID-19 transmission. RESULTS: The spatial spillover effects of NPIs explain [Formula: see text] [[Formula: see text] credible interval: 52.8-[Formula: see text]] of national cumulative confirmed cases, suggesting that the presence of the spillover effect significantly enhances the NPI influence. Simulations based on the S-SEIR model further show that increasing interventions in only a few states with larger intrastate human mobility intensity significantly reduce the cases nationwide. These region-based interventions also can carry over to interstate lockdowns. CONCLUSIONS: Our study provides a framework for evaluating and comparing the effectiveness of different intervention strategies conditional on NPI spillovers, and calls for collaboration from different regions.

Compaction of Hydrophobic Molybdenum Disulfide Coatings for Promoting Tribological Behaviors on Engineering Steel.

Ambient environment has a crucial effect on the lubrication performance of molybdenum disulfide (MoS2) coatings. In this work, we fabricated porous MoS2 coatings via a facile optimized aerosol-assisted chemical vapor deposition (AACVD) method. It is found that the obtained MoS2 coating demonstrates outstanding antifriction and antiwear lubrication performance with the coefficient of friction (COF) and wear rate as low as 0.035 and 3.4 × 10-7 mm3/Nm in lower humidity (15 ± 5)%, respectively, which is comparable to the lubrication ability of pure MoS2 in vacuum. In addition, the hydrophobic property of porous MoS2 coatings is suitable for infusing lubrication oil to achieve stable solid-liquid lubrication in higher humidity (85 ± 2)%. The composite lubrication system shows excellent tribological behavior in both dry and wet environments, which will alleviate the sensitivity of the MoS2 coating to the environment and ensure the service life of the engineering steel in complex industrial backgrounds.

From waste-activated sludge to algae: a self-reliant cultivation process in photoreactors using saline conditions.

In this study, microalgae-bacteria (MB) systems using saline conditions (3 and 5% salinity) were built in order to use waste-activated sludge (AS) as raw material for cultivating lipid-rich microalgae. Algae were observed to be flourishing in 60 days of operation, which totally used the N and P released from the sludge biomass. A prominent improvement of lipid content in MB consortia was obtained under algae growth and salinity stimulation, which occupied 119-136 mg/g-SS rather than a low content of 12.1 mg/g-SS in AS. Lipid enrichment also brought a 3.1-3.3 times total heat release (THR) in the MB biomass. The marine spherical algae Porphyridium, as well as filamentous Geitlerinema, Nodularia, Leptolyngbya were found to be the main lipid producers and self-flocculated to 23.0% (R1) and 33.5% (R2) volume under the effect of residue EPS. This study had a big meaning in not only waste sludge reduction but also in manufacturing useful bioenergy products.

Construction and Evaluation of Nomogram for Hematological Indicators to Predict Pathological Response after Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer.

OBJECTIVE: A retrospective study was conducted by developing prediction models to evaluate the association between hematological indexes, their changes during neoadjuvant chemoradiotherapy (NCRT), and tumor pathological response in patients with locally advanced rectal cancer. METHODS: The clinical data of 202 patients who received NCRT and radical surgery in Sichuan Cancer Hospital were retrospectively analyzed. Univariate and logistic multivariate regression analyses were used to identify hematological indexes with predictive significance. The independent risk factors were imported into the R software, and a nomogram prediction model was developed. The bootstrap method and ROC curve were used to evaluate the discriminative degree of the model. RESULTS: Univariate analysis demonstrated age, tumor diameter, preoperative T, distance from tumor to the anal verge, CEA before NCRT, preoperative CEA, lymphocyte changes, platelet changes, and pathology of rectal cancer after NCRT were associated. Multivariate analysis demonstrated that age, tumor distance from the anus, preoperative CEA, lymphocyte changes, and platelet changes were independent risk factors. The independent risk factors were imported into the R software to construct a nomogram model. The area under the ROC was 0.76, and the slope of the calibration curve of the nomogram was close to 1. CONCLUSION: A low preoperative CEA level, a young age, a high tumor from the anal verge, the maintenance of circulating lymphocyte level, and a decreased platelet level after NCRT are important factors for favorable outcomes after NCRT. Developing a nomogram prediction model with good discrimination and consistency can provide some guidance for predicting pathological responses after NCRT.

Unity Human Eye Model for Gaze Tracking with a Query-Driven Dynamic Vision Sensor.

Objective measurement of gaze pattern and eye movement during untethered activity has important applications for neuroscience research and neurological disease detection. Current commercial eye-tracking tools rely on desk-top devices with infrared emitters and conventional frame-based cameras. Although wearable options do exist, the large power-consumption from their conventional cameras limit true long-term mobile usage. The query-driven Dynamic Vision Sensor (qDVS) is a neuromorphic camera which dramatically reduces power consumption by outputting only intensity-change threshold events, as opposed to full frames of intensity data. However, such hardware has not yet been implemented for on-body eye-tracking, but the feasibility can be demonstrated using a mathematical simulator to evaluate the eye-tracking ca-pabilities of the qDVS under controlled conditions. Specifically, a framework utilizing a realistic human eye model in the 3D graphics engine, Unity, is presented to enable the controlled and direct comparison of image-based gaze tracking methods. Eye-tracking based on qDVS frames was compared against two different conventional frame eye-tracking methods - the traditional ellipse pupil-fitting algorithm and a deep learning neural network inference model. Gaze accuracy from qDVS frames achieved an average of 93.2% for movement along the primary horizontal axis (pitch angle) and 93.1 % for movement along the primary vertical axis (yaw angle) under 4 different illumination conditions, demonstrating the feasibility for using qDVS hardware cameras for such applications. The quantitative framework for the direct comparison of eye tracking algorithms presented here is made open-source and can be extended to include other eye parameters, such as pupil dilation, reflection, motion artifact, and more.

Robust Transparent Titanium Dioxide Coating Based on the AACVD Process for Anticorrosion Marine Exploration.

Transparent and robust titanium dioxide (TiO2) coatings were prepared by the facile aerosol-assisted chemical vapor deposition (AACVD) method. The effects of deposition temperature and precursor concentration on the crystal growth and optical properties of TiO2 coating were investigated. It is found that the obtained TiO2 coating has strong adhesion to the substrate, which can effectively avoid mechanical scratches and wear by sharp objects, adhesive tape and steel wool. Besides, in the marine corrosion protection test, both the open circuit potential and electrochemical impedance of TiO2 coating immersed in artificial seawater for different times are greater than those of the bare S420 steel substrate. Particularly, the high-frequency phase angle of the TiO2 coating increases, and the impedance value at low frequency of 0.10 Hz is about 2 orders of magnitude higher than that of the bare S420 substrate. In addition, the significant decrease of corrosion products on the surface further proves that the deposited TiO2 coating exhibits better corrosion inhibition and excellent anticorrosion properties, which is expected in application of the surface coating protection of the marine exploration lens.

Analysis of Risk Factors for Anastomotic Leakage After Laparoscopic Anterior Resection of Rectal Cancer and Construction of a Nomogram Prediction Model.

Objective: To explore the risk factors of anastomotic leakage (AL) after laparoscopic anterior resection (AR) of rectal cancer and establish a nomogram prediction model. Methods: Clinical and surgical data of patients who underwent AR of rectal cancer at Sichuan Cancer Hospital from January 2017 to December 2020 were retrospectively collected. Univariate and multivariate logistic regression analyses were used to screen the independent risk factors of AL after AR. A nomogram risk prediction model was established based on the selected independent risk factors and the predictive performance of nomogram was evaluated. Results: A 1013 patients undergoing laparoscopic AR were included, of which 67 had AL, with an incidence of 6.6%. Univariate and multivariate logistic regression analyses showed that male gender, tumors distance from the anus verge of ≤ 5cm, tumors distance from the anus verge of 5-10cm, circumferential tumor growth, operation time ≥ 240min, and no diverting stoma were independent risk factors for AL after AR. A nomogram prediction model was established based on these results. The calibration curve showed that the predicted occurrence probability of the nomogram model was in good agreement with the actual occurrence probability. The area under the receiver operating characteristic (ROC) curve was 0.749. Conclusion: The nomogram prediction model based on the independent risk factors of patients undergoing AL after AR can effectively predict the probability of AL.

Mussel-Inspired Interfacial Modification for Ultra-Stable MoS2 Lubricating Films with Improved Tribological Behavior on Nano-Textured ZnO Surfaces Using the AACVD Method.

Friction-associated energy loss and mechanical wear leading to failure is a major problem in industries. To mitigate this, the design and testing of novel lubricants is important. Here, we show the facile one-pot synthesis of ZnO/ZnO nanorods (NRs) and MoS2 films on pre-treated glass substrates via aerosol-assisted chemical vapor deposition. The bearing capacity and wear life of ZnO film/ZnO NRs/MoS2 films were improved due to the lubricant retention capabilities of the NRs. Modification of the ZnO/MoS2 nano-arrays using polydopamine (PDA) allowed the realization of robust and ultra-stable solid lubricants through the triple action of chemical chelation, layered materials, and nanotexture, especially under heavy load conditions. Compared with pristine MoS2, the adhesion and bearing strength of the composite film increased by 11 and 30 times, respectively, while the coefficient of friction and wear rate decreased by 94 and 85%, respectively. This is because the chelation between the transition metal and the groups in the interlayer PDA was fully utilized to improve the interface compatibility, which significantly improves the robustness of ZnO NRs and the adhesion of MoS2. This allowed a stable and firm mechanical lock between the substrate, lubricant films, and the steel ball. It demonstrated a convenient method to achieve the antifriction and anti-wear of solid lubricating materials by PDA interface modification for practical industrial applications.

Effects of itraconazole and rifampicin on the pharmacokinetics and safety of youkenafil, a novel phosphodiesterase type 5 inhibitor, in healthy Chinese subjects.

Youkenafil is a novel selective phosphodiesterase type 5 inhibitor to treat erectile dysfunction. In order to study the drug-drug interactions of youkenafil, in vitro experiments were conducted with human liver microsomes and recombinant isoenzymes to identify the effect of cytochrome P450 (CYP) enzymes on the metabolism of youkenafil. Then two clinical studies were performed to investigate the effects of itraconazole and rifampicin (potent CYP3A4/5 inhibitor and inducer, respectively) on the pharmacokinetics of youkenafil and its main metabolite, N-desethyl youkenafil (M1). Each study enrolled thirty healthy male subjects. In study 1, subjects were given a single dose of youkenafil (50 mg on Days 1 and 13) and multiple doses of itraconazole (200 mg once daily from Days 6 to 14). In study 2, subjects were given a single dose of youkenafil (100 mg on Days 1 and 20) and multiple doses of rifampicin (600 mg once daily from Days 6 to 20). The results showed that youkenafil was mainly metabolized through CYP3A4/5 in vitro. Itraconazole increased youkenafil AUC and Cmax by about 12- and 6-fold, respectively, and increased M1 AUC and Cmax by 5- and 1.3-fold, respectively. Conversely, rifampicin reduced youkenafil AUC and Cmax both by about 98%. It did not change the AUC of M1 significantly, but increased the Cmax by 30%. All treatments were well tolerated by subjects in both studies. Therefore, co-administration of youkenafil with potent inhibitors or inducers of CYP3A4/5 should be avoided or carefully monitored.

Pharmacokinetics and Bioequivalence of a Generic and a Branded Pazopanib Tablet in Healthy Chinese Subjects.

This study aimed to evaluate the bioequivalence of two pazopanib tablet formulations in healthy Chinese subjects. A randomized, open-label, single-dose, two-period, two-sequence, crossover study was conducted under fasting conditions. A total of 32 eligible subjects were randomly administered a single dose of a 200-mg generic or branded pazopanib tablet with a 16-day washout period. Blood samples were collected before and up to 72 hours after dosing. Pharmacokinetic parameters were analyzed with noncompartmental analysis. Safety assessments included physical examinations, laboratory tests, and adverse events reporting. Maximum plasma concentration (Cmax ), area under the plasma concentration-time curve (AUC) from zero to the last quantifiable concentration (AUC0-t ), and AUC from zero to infinity (AUC0-∞ ) were similar between the generic and branded products (all P > .05). The 90% confidence intervals of the geometric mean ratio of the test/reference products for Cmax , AUC0-t , and AUC0-∞ were 89.1%-117.1%, 81.9%-108.5%, and 82.4%-109.6%, respectively. There were no serious adverse events during the study. The newly developed generic pazopanib tablet was bioequivalent to the reference product under fasting conditions. Both formulations were well tolerated in healthy Chinese volunteers.

Rapid LC-MS/MS detection of different carbapenemase types in carbapenemase-producing Enterobacterales.

Klebsiella pneumoniae carbapenemase (KPC)-2, metallo-beta-lactamases (MBL), and oxacillinase (OXA)-48-like carbapenemases are considered the most important carbapenemases. In vitro studies have demonstrated that the carbapenemase activity of KPC-2 and MBL can be inhibited by 3-aminophenylboronic acid and ethylenediaminetetraacetic acid (EDTA), respectively. Understanding the carbapenemase types expressed in carbapenem-resistant Enterobacterales (CRE) is of great significance to clinical therapies. Liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS) is fast, stable, and specific; and is considered the gold standard method for measuring small molecules. In this study, we developed carbapenemase inhibition tests combined with LC-MS/MS to rapidly identify carbapenemase types. A total of 295 clinical isolates were examined, including 212 KPC-2 producers, 29 MBL producers, 15 OXA-48-like producers, 3 KPC-2 + OXA-232 producers, and 36 carbapenem-sensitive strains. We used LC-MS/MS to determine the carbapenemase types by measuring the ratio of the hydrolyzed meropenem peak areas in the presence and absence of different inhibitors. The sensitivity and specificity of LC-MS/MS in detecting single KPC-2 producers were 97.64% and 100.00%, respectively, and 96.55% and 100.00% for MBL producers, respectively. In addition, the sensitivity and specificity of LC-MS/MS in detecting single OXA-48-like producers were both 100.00% when extending incubation time up to 2.5 h. LC-MS/MS showed excellent agreement in detecting carbapenemase types using the modified carbapenem inactivation (mCIM)/EDTA-carbapenem inactivation assay (eCIM) (kappa = 0.93 for serine carbapenemases and kappa = 0.98 for MBL carbapenemases). In this study, LC-MS/MS demonstrated excellent detection of different carbapenemase types, showing potential reliability in future clinical applications.

Evaluation of LAMP assay using phenotypic tests and PCR for detection of blaKPC gene among clinical samples.

BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) infection constitutes a public health threat, which blaKPC was the major carbapenemases concerned in China. Timely and efficient diagnosis is of paramount importance for controlling the spread of drug-resistant bacteria. Here, we develop an approach based on loop-mediated isothermal amplification (LAMP) for rapid confirmation of blaKPC within 60 min from samples collected. METHODS: We designed primers specific to detect blaKPC and evaluated it for its sensitivity and specificity of detection using real-time monitoring. Five hundred forty-six clinical specimens were analyzed by the LAMP assay and compared with the phenotypic tests and PCR. The samples with inconsistent results were further verified by Sanger sequencing. RESULTS: The LAMP assay displayed a detection limit of 1 × 102  CFU/ml, which was 10-fold more sensitive than the PCR. No cross-reactivity was observed for strains that produced other types of ß-lactamase. Furthermore, we demonstrated concordant results (Kappa > 0.75) between the genotypic method and phenotypic tests for the 546 clinical samples. The data presented in this study suggested that the genotypic method is a reliable assay for identifying blaKPC-induced CRE in China. The results of the Sanger sequencing indicate that the developed method not only has high accuracy but also meets the need for rapid diagnosis, while the PCR method is prone to false negatives. CONCLUSIONS: We successfully constructed a LAMP technique that can be used for auxiliary diagnosis of CRE, which is faster, cheaper, and more accurate than the PCR. It may therefore be routinely applied for detection of blaKPC producers in routine clinical laboratories.