Value Of Upper Limit Research Articles

Behaviour of paddled energy-absorbing rockbolts under complex loading laboratory conditions

Since their introduction in 2010, paddled energy-absorbing rockbolts have been widely used in seismically active hard rock mines. This paper provides new data and reviews previous work to quantify the performance of paddled energy-absorbing rockbolts under controlled laboratory conditions. Of significance is the realization that the typical split location in impact tests, at the centre between two paddle anchor points can at best provide an upper limit value. This inherent variability in performance under different testing configurations should be acknowledged and taken into consideration in the design of ground support in seismic conditions. This paper discusses the reduction in capacity of paddled rockbolts as a function of loading angle from a maximum value during axial tests (0° loading angle) to the lowest value during pure shear (loading angle of 90°). A significant reduction in displacement capacity is observed as the loading angle changes between axial (0°) and 40°. Beyond a 40° loading angle up to shear (90°) loading the reduction in displacement capacity is less significant. Due to the variances in the capacity observed through the variance of the testing configuration: loading mechanism, direction of loading, location / presence of a discontinuity, it must be recognized that results from laboratory-based testing are not independent of the testing configuration. This should be acknowledged when extrapolating anticipated performance in the field.

Evaluation of the Physicochemical Quality of Irrigation Water from the Wells of Laya Doula, CR of Nialia, Prefecture of Faranah, Republic of Guinea

This research aims to evaluate the physicochemical quality of well irrigation water, used by market gardening groups in the District of Laya Doula, CR Nialia, Faranah prefecture, Republic of Guinea. Direct observation and analyses are carried out, direct observation consists of taking stock of the situation and identifying sampling points. The pH, temperature, turbidity, nitrite and nitrate are determined according to standard standards. A mapping of water sources is carried out. Water samples were taken from four (4) wells. The results show that the pH of the wells (PLD1, PLD2, PLD3 and PLD4) comply with WHO standards, and the temperatures are well below 35°C as the upper indicative limit value for water intended for irrigation according to BELGYTI (2009). From the point of view of turbidity, three wells (PLD1, PLD3 and PLD4) out of four are turbid because their turbidity exceeds the limit value defined by the WHO which is (5 NTU). The water samples are not polluted with Nitrite and Nitrate. In short, the results of analyses of the water samples showed that the majority of the physicochemical parameters meet the WHO standards. Keywords: Physicochemical parameters, water, wells, irrigation, Guinea.

Assessment of whole-body vibration and development of mitigation intervention for single-axle tractor–trailer combination

IntroductionTractarization is synonymous with farm mechanization in India. Tractor-trailers are extensively used for the transportation of farm inputs and produce on and off-road, exposing drivers to excessive vibration.ObjectivesThe study was undertaken to assess tractor drivers’ vibration exposure while using trailers and to develop low-cost mitigation interventions.MethodologyThe whole-body vibrations were measured at the tractor seat during the transportation with a no, half (3715 kg soil) and full payload (5910 kg soil) trailer on two terrain conditions, namely, asphalt and farm terrains. The speeds recommended by ISO 5008-1979 of 10, 12 and 14 km/h on asphalt roads and 4, 5 and 7 km/h on farm roads, as well as actual working speeds preferred by the operator (18, 20 and 22 km/h on asphalt road and 8, 10 and 12 km/h on farm terrain), were selected for experiments. Two vibration reduction interventions, namely spring suspended single point hitch (I1) and polyurethane (PU) bush (I2), were developed and installed between the tractor and trailer. Whole-body vibration (WBV) was measured by repeating the experiments.ResultsThe maximum vibration reduction on asphalt road at 22 km/h with I1 was found as 14.3, 19.03 and 23.1%, whereas on-farm terrain at 12 km/h was found as 15.16, 22.43, and 25.56% for no, half and full payload. Similarly, with I1 + I2 interventions, the maximum total vibration reduction at 22 km/h was 16.86, 21.12 and 25.51% on asphalt roads, whereas on-farm tertian at 12 km/h was 17.07, 23.77 and 28.67%. The average value of lower health guidance caution zone (HGCZ) limits on asphalt roads increased by 1.11, 0.95 and 0.92 h and on-farm tertian 1.55, 1.14 and 0.83 h with no, half, and full payload. The average value of upper HGCZ limits on asphalt roads increased by 3.13, 3.21 and 3.68 h and on-farm tertian by 2.24, 2.94 and 3.31 h with intervention.ConclusionsThis infers that with developed interventions an operator can safely perform for a longer duration and at higher operational speeds because of the reduced vibration.

Prepackaged foods healthiness ranking index: developing front-of-pack labeling to facilitate the assessment and validation of healthiness rankings of prepackaged foods in China

BackgroundThe Medium and Long-Term Plan for the Prevention and Treatment of Chronic Diseases (2017–2025) in China has highlighted the importance of reducing fat, sodium, and sugar in foods. However, front-of-pack labeling, which enables consumers to assess the health levels of prepackaged foods, is lacking in China. In response to the Zhejiang Provincial Health Commission’s request, we sought to develop a method for efficiently evaluating the health level of prepackaged foods.MethodsThrough a comprehensive literature review, we established a systematic framework: the Prepackaged Foods Healthiness Ranking Index (PHRI). We determined specific threshold values and grading criteria and conducted two rounds of Delphi survey to refine the index. Using a measurement dataset, we aimed to determine the optimal limit values for assessing the health level of prepackaged foods in real-world settings.ResultsAfter two rounds of Delphi surveys, the PHRI underwent multiple revisions until consensus among experts was reached. The final decision regarding the upper limit values set 30% Nutrient Reference Values as the limit for solid foods and 15% Nutrient Reference Values for liquid foods. The calculation of PHRI values was successfully implemented with the dataset, in accord with current nutrition awareness and real-world conditions.ConclusionsThe PHRI provides a valuable tool for assessing the healthiness of prepackaged foods. This front-of-pack labeling system provides a convenient method for evaluating the nutritional quality of prepackaged foods. Ultimately, the PHRI has the potential to contribute to advancements in health policy, practice, and education in China.

Evaluation of Etest and MICRONAUT-AM Assay for Antifungal Susceptibility Testing of Candida auris: Underestimation of Fluconazole Resistance by MICRONAUT-AM and Overestimation of Amphotericin B Resistance by Etest.

Multidrug-resistant Candida auris has recently caused major outbreaks in healthcare facilities. Rapid and accurate antifungal susceptibility testing (AST) of C. auris is crucial for proper management of invasive infections. The Commercial Sensititre Yeast One and Vitek 2 methods underestimate or overestimate the resistance of C. auris to fluconazole and amphotericin B (AMB). This study evaluated the AST results of C. auris against fluconazole and AMB by gradient-MIC-strip (Etest) and broth microdilution-based MICRONAUT-AM-EUCAST (MCN-AM) assays. Clinical C. auris isolates (n = 121) identified by phenotypic and molecular methods were tested. Essential agreement (EA, ±1 two-fold dilution) between the two methods and categorical agreement (CA) based on the Centers for Disease Control and Prevention's (CDC's) tentative resistance breakpoints were determined. Fluconazole resistance-associated mutations were detected by PCR-sequencing of ERG11. All isolates identified as C. auris belonged to South Asian clade I and contained the ERG11 Y132F or K143R mutation. The Etest-MCN-AM EA was poor (33%) for fluconazole and moderate (76%) for AMB. The CA for fluconazole was higher (94.2%, 7 discrepancies) than for AMB (91.7%, 10 discrepancies). Discrepancies were reduced when an MCN-AM upper-limit value of 4 µg/mL for fluconazole-susceptible C. auris and an Etest upper-limit value of 8 µg/mL for the wild type for AMB were used. Our data show that resistance to fluconazole was underestimated by MCN-AM, while resistance to AMB was overestimated by Etest when using the CDC's tentative resistance breakpoints of ≥32 µg/mL for fluconazole and ≥2 µg/mL for AMB. Method-specific resistance breakpoints should be devised for accurate AST of clinical C. auris isolates for proper patient management.

Command filtered‐based fixed‐time fault‐tolerant tracking control for nonlinear systems

AbstractAs for a class of strict‐feedback nonlinear systems with simultaneous sensor and actuator faults, the article focuses on the problem of fixed‐time fault‐tolerant control. Both fixed‐time command filters and a compensation mechanism are utilized to cope with these issues of differential explosion and filter errors. Meanwhile, through the fusion of fixed‐time control, fuzzy logic systems, adaptive control and the backstepping technology, a ‐step design scheme is presented. Our proposed controller ensures the fixed‐time convergence of all the signals in the system even with sensor/actuator faults, and allows the designers to acquire the upper limit value of the fixed convergence time only by tuning the design parameters. And this scheme takes into account rapidity, adaptability and fault tolerance of the system simultaneously. Based on the numerical simulation analysis, it is shown that the better tracking performance can be achieved. So it is concluded that our strategy is effective.

Research and Implementation of Aurora Protocol NFC System

Abstract Aurora protocol is a high-speed serial communication protocol with characteristics such as high speed, low latency, open source and free. It is widely used in application fields that require a large amount of data transmission. However, Aurora communication systems also has the problem of data loss, making flow control a challenge; This paper analyzes the problem of data loss, finds out the root cause, and designs an NFC(Native Flow Control) system for the Aurora protocol. The system uses AXI4-Stream bus for communication and solves the problem by controlling the Aurora module to send NFC PAUSE code at the sending end. At the same time, by setting a reasonable upper limit value in the flow control program, the problem of data loss caused by NFC Latency is solved, and effective flow control is achieved.

Analysis of axial force variations and seismic performance of subway station columns under earthquake loading

Central column failure is a predominant seismic damage mode in subway station structures. During seismic events, the central columns’ vertical compressive force, as indicated by the axial compression ratio (ACR), undergoes continuous variations, significantly impacting both their failure modes and the seismic performance. This study involved establishing a finite element model of a subway station and conducting time history analyses to identify the distinct variation patterns of ACR in central columns for various seismic design scenarios. Based on these summarized patterns, appropriate ACR variations were designed for the columns, and the validity of the column model was confirmed using experimental data, enabling analyses of their failure modes and hysteresis characteristics under cyclic loads. Lastly, a sensitivity analysis of the parameters associated with the central columns was performed. The results demonstrated that the horizontal displacement and the ACR of the top of the central column were asynchronous, the frequency of the latter was 1.4–3.8 times that of the former, and the amplitude of the ACR was 0.08–0.68. When the frequency of the variable ACR was odd times, the damage and hysteresis curve of the column showed obvious asymmetry and harmfulness, and it exacerbated the damage to the core concrete of the column. Compared to applying a constant ACR, the bearing capacity and energy dissipation of the column were even reduced by about 50 % and 74 %, respectively. The specimens with the upper limit value of 0.95 of variable ACR had even more adverse effects on the damage and hysteresis behavior of the column than the scheme with a constant ACR of 0.95. In addition, the even multiple frequency of variable ACR had a limited effect on the seismic performance of the column, but the harm caused by the large amplitude variation of variable ACR could not be ignored. As to the impacts of structural parameters under cyclic loadings, elevating the longitudinal reinforcement ratio and decreasing the stirrup spacing within the central columns would substantially enhance energy dissipation capacity, with a maximum increase of about 69 %. Meanwhile, for columns with the same cross-sectional area, square columns exhibited superior hysteresis behavior compared to their circular counterparts. The findings of this study could provide guidance for the engineering design of the central columns.

Experimental study of the effect of crude oil water content on boilover fire

When a tank experiences a boilover fire, oil droplets splash, heat release rate and flame height increase, posing significant hazards. Water is a necessary condition for boilover to occur, but current research mainly focuses on boilover caused by water layer, neglecting the influence of water content inherent in crude oil on boilover phenomena. In this study, crude oil with a water content ranging from 0.26 % to 3 % was utilized, and a series of boilover fire experiments were conducted by varying the presence or absence of a water layer and the initial oil thickness and by carrying out a series of boilover fire experiments focusing on the effect of water content on the boilover phenomenon. The results indicate that emulsified crude oil has a droplet micro-explosion phase during the stable combustion stage. When no water layer is present, the boilover process duration is brief, and the transient injection effect is notable, with boilover intensity increasing with water content. Upon adding a water layer, emulsified water abbreviates the boilover onset time, diminishes the combustion rate, and promotes the formation of the hot zone. The upper and lower limit values of the hot zone temperature decrease with increasing water content, while the temperature difference remains essentially unaffected, remaining constant at about 50 °C. Boilover intensity exhibits a nonlinear relationship with increasing water content, peaking at 2 % water content. The pre-boilover burned mass ratio remains relatively stable, maintained between 12 % and 15 % across all working conditions. Both the splash range and maximum heat flux increase with initial oil layer thickness but show no significant change with water content. Moreover, the safety distance corresponding to the heat radiation threshold exceeds the splash distance, indicating that heat radiation hazards predominate. The results of this paper will help provide guidance for fighting emulsified crude oil fires.

Daily and Weekly "High Doses" of Cholecalciferol for the Prevention and Treatment of Vitamin D Deficiency for Obese or Multi-Morbidity and Multi-Treatment Patients Requiring Multi-Drugs-A Narrative Review.

Daily vitamin D supplementation using higher than normal dosing (up to the upper limit value) and intermittent (once or twice per week) dosing were studied in patients with increased risk of vitamin D deficiency. Using a PubMed database, a thorough search for published randomized controlled trials and other studies was conducted, and the results were analyzed. This review provides an overview of the use of 7000 IU daily, 30,000 IU per week or twice weekly, and 50,000 IU weekly of vitamin D for obtaining and maintaining 25(OH)D concentrations of at least 30 ng/mL in patients at high risk of vitamin D deficiency. The abovementioned dosages should be considered in adults with obesity, liver disease or malabsorption syndromes, or multi-diseased patients, mainly seniors requiring multi-drug treatment, including drugs affecting vitamin D metabolism. The simple schedules of 7000 IU/day, 30,000 IU/week or twice weekly, and 50,000 IU/week for use by patients with an increased risk of vitamin D deficiency were provided for consideration. Without monitoring of 25(OH)D, daily doses of 7000 IU or intermittent doses of 30,000 IU/week should be considered for a prolonged time as prophylactic or maintenance doses, mainly in obese patients, patients with liver disease and patients with malabsorption syndromes. For the treatment of possible vitamin D deficiency without assessment of 25(OH)D in these groups, intermittent doses of 30,000 IU twice weekly or 50,000 IU per week should be considered for a 6-8-week period only. The higher daily doses or the intermittent doses suggested above are effective, safe and responsive based on patient's preferences.

Determining the reliability of complex RES by through decomposition by lower and upper limit values

Formulation of the problem. Reliability modeling of complex systems can be greatly simplified by decomposition into its component elements. However, as the number of objects in complex systems increases, modeling and analyzing their reliability becomes more labor-intensive, even when using methods based on finite formulas. One reason for the complexity is the increasing number of possible states of the system. Target. To facilitate the process of calculating the reliability of complex radio-electronic systems, you can apply the method of calculating the lower and upper limit values of reliability indicators. Results. In the process of accurately calculating indicators for each possible state of the system, we can estimate the minimum and maximum values of these indicators. Practical significance. Estimation of the lower and upper values of reliability indicators allows present the range of values within which the real value of the reliability indicator lies. It helps to take into account a variety of factors, such as different operating conditions, variations in production process, statistical deviations and other variations in the system.

The Cyclic Performance and Macro-Simplified Analytical Model of Internal Joints in RC-Assembled Frame Structures Connected by Unbonded Prestressed Strands and Mortise-Tenon Based on Numerical Studies

This paper introduces a novel type of connection that integrates unbonded prestressed strands (UPS) and mortise-tenon in an assembly frame structure (UPS-MTF). First, the damage process and failure modes of the joints under reciprocating horizontal loads were systematically analyzed using refined numerical models. The recommended values of the design parameters of the joints were derived from the parametric analysis results. Refined numerical modeling results reveal the diagonal compression strut mechanism within the core region of the joint. The diagonal compression struts model assists in establishing the theoretical calculation formula for the skeleton curve of shear stress–strain in the core region. Second, a genetic algorithm (GA) parameter was identified for the restoring force model of the core region to determine the parameters of the hysteresis rules. Finally, a macro-simplified analytical model of the joint was created based on the restoring force model of the core region, and parameter analysis was conducted to verify the applicability of this macro-simplified analytical model. The research results prove that the damaged form of the joint proposed in this paper originates from the shear and relative slip damage between the components in the core region. The axial compression ratio significantly affects the hysteretic performance of the joints, and the upper and lower limit values were identified for the axial compression ratio of the joints. The area and initial effective stress of the UPS exert a minimal effect on the hysteretic performance of the joint. Based on the method proposed in this paper for determining the restoring force model in the core region of the joints, the hysteresis curves obtained from the macro-simplified analytical model closely match the refined numerical analysis model results. This correspondence verifies the applicability of the macro-simplified analytical model.

A novel Zende’s-TOPSIS method towards estimation of measurement uncertainty in hole diameters

The ‘Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS)’ is one of the best methods for ‘Multi-Criteria Decision-Making’ and ‘Multi-Objective Optimization’. The traditional TOPSIS method determines the best alternative under fixed conditions. However, it cannot determine the best upper limit and lowest limit values. This work explains the detailed methodology of the newly developed Zende’s-TOPSIS method which was used to estimate the measurement uncertainty in hole diameters. Four identical holes and one center hole in an industrial component were measured to investigate measurement uncertainty. According to the experimental results, Zende’s-TOPSIS method performed better than the traditional TOPSIS method. The percentage improvement in the Zende’s-TOPSIS method over the traditional TOPSIS method ranges from 0.0209% to 0.3053%. Using Zende’s-TOPSIS method, the percentage maximum measurement uncertainty for four identical holes varies from 0.8067% to 1.0222%, whereas for the center hole, it varies from 0.5261% to 0.5576%. Similarly, the percentage minimum measurement uncertainty for four identical holes varies from 0.3839% to 0.6406%, whereas for the center hole, it varies from 0.4014% to 0.4041%. The proposed method is also capable of estimating the machined tolerances of the component, which ranges from 18.0772 mm to 18.1708 mm for four identical holes and 49.2215 mm to 49.2572 mm for the center hole. The proposed method can solve various ‘Multi-Objective Optimization’ problems.

A forward design approach for fault thresholds in redundant flight control systems

Modern fly-by-wire flight control systems use redundancy configurations to meet high safety requirements. The fault threshold value of the redundancy monitoring and voting algorithm affects the false alarm rate and missing alarm rate of the flight control system and the excessive false alarm rate and missing alarm rate reduce the reliability of the flight control system. Traditionally, the design of fault threshold is based on the empirical trial-and-error method, which suffers from the problem of unclear optimization direction. Forward design is needed to improve design efficiency and quality. In this paper, a forward design method for fault detection threshold is proposed to determine the upper limit value of the fault threshold by analyzing the effect of the voting signal change on the transient response of the aircraft when a channel fault occurs. The lower limit value of the fault threshold is determined by analyzing the channel history data. The effectiveness of the design method is demonstrated by digital simulation.

Transforaminal endoscopic lumbar discectomy with two-segment foraminoplasty for the treatment of very highly migrated lumbar disc herniation: a retrospective analysis.

The surgical resection of very highly migrated lumbar disc herniation (VHM-LDH) is technically challenging owing to the absence of technical guidelines. Hence, in the present study, we introduced the transforaminal endoscopic lumbar discectomy (TELD) with two-segment foraminoplasty to manage VHM-LDH and evaluated its radiographic and midterm clinical outcomes. The present study is a retrospective analysis of 33 consecutive patients with VHM-LDH who underwent TELD with two-segment foraminoplasty. The foraminoplasty was performed on two adjacent vertebrae on the basis of the migration direction of disc fragments to fully expose the disc fragments and completely decompress the impinged nerve root. The operation duration, blood loss, intra- and postoperative complications, and recurrences were recorded. Additionally, imageological observations were evaluated immediately after the procedure via magnetic resonance image and computerized tomography. Clinical outcomes were evaluated by calculating the visual analog scale (VAS) score and Oswestry Disability Index (ODI). The MacNab criterion was reviewed to assess the patients' opinions on treatment satisfaction. The resection rate of bony structures were quantitatively evaluated on postoperative image. The segmental stability was radiologically evaluated at least a year after the surgery. Additionally, surgery-related and postoperative complications were evaluated. The average age of the patients was 56.87 ± 7.77 years, with a mean follow-up of 20.95 ± 2.09 months. The pain was relieved in all patients immediately after the surgery. The VAS score and ODI decreased significantly at each postoperative follow-up compared with those observed before the surgery (P < 0.05). The mean operation duration, blood loss, and hospital stay were 56.17 ± 16.21min, 10.57 ± 6.92 mL, and 3.12 ± 1.23 days, respectively. No residual disc fragments, iatrogenic pedicle fractures, and segmental instability were observed in the postoperative images. For both up- and down- migrated herniation in the upper lumbar region, the upper limit value of resection percentage for the cranial SAP, caudal SAP, and pedicle was 33%, 30%, and 34%, respectively; while those in the lower lumbar region was 42%, 36%, and 46%, respectively. At the last follow-up, the satisfaction rate of the patients regarding the surgery was 97%. Surgery-related complications including dural tear, nerve root injury, epidural hematoma, iatrogenic pedicle fractures, and segmental instability were not observed. One patient (3%) suffered from the recurrence of LDH 10 months after the initial surgery and underwent revision surgery. The TELD with two-segment foraminoplasty is safe and effective for VHM-LDH management. Proper patient selection and efficient endoscopic skills are required for applying this technique to obtain satisfactory outcomes.

Structural, Mechanical, and Optoelectronic Properties of CH3NH3PbI3 as a Photoactive Layer in Perovskite Solar Cell

The structural, electronic, mechanical, and optical properties of pseudo-cubic CH3NH3PbI3 perovskite have been studied within the framework of density functional theory, in line with solar cell applications. The computed values of lattice and elastic constants concurred with the available theoretical and experimental data. This compound has a semi-conducting behavior, with a direct band gap of about 1.49 eV. Note that the solar radiation spectrum has a maximum energy intensity value of approximately 1.50 eV. Thus, semiconductors with such gaps are preferred for photovoltaic applications. Its elastic parameters reveal that it is a ductile material that is mechanically stable. Optical descriptors such as refractive index, reflectivity, extinction, energy loss, and absorption have been explored with the aim of establishing the optical features of the material. Our findings demonstrate that this perovskite is suitable for solar cell applications based on the size and nature of the band gap, as also supported by the obtained upper limit value of simulated power conversion efficiency via the spectroscopic limited maximum efficiency mathematical model.

Analysis of Accident Risk Points (Black Spots) on the Bubutan – Perak Barat Road Section Surabaya

According to the traffic accident data from the Traffic Accident Unit of the Tanjung Perak Port Police and the Traffic Accident Unit of the Dukuh Pakis Police in Surabaya City in 2020-2022, traffic accidents that occurred on the Bubutan Road - West Perak Road section experienced an increase in the number of traffic accidents. The total details in 2021 were 13 incidents, in 2022 there was an increase to 17 incidents, besides that, the material losses incurred in 2022 had the highest figure, which amounted to IDR 46,000,000. So it is necessary to analyze the accident-prone points on the road section. The method used are AEK (Accident Equivalent Number), IPA (Importance Performance Analysis) method, and calculation of free flow speed, traffic volume analysis, and side obstacle analysis. Based on the analysis of accident-prone areas using the AEK method, it is known that the upper control limit value is 36.07 where Jalan Perak Barat has an AEK value above the BKA value in 2021 of 37, then in 2022 of 40. Jalan Perak Barat has an average traffic volume of 434.47 smp / hour, with a moderate level of side obstacles, but has a free flow speed that exceeds the planned speed. One of the factors causing traffic accidents on Jalan Perak Barat is the driver of a vehicle traveling at high speed, so rumble strip planning and road facility rejuvenation are recommended.

Evaluation of the Vitek 2 system for antifungal susceptibility testing of Candida auris using a representative international panel of clinical isolates: overestimation of amphotericin B resistance and underestimation of fluconazole resistance.

Although the Vitek 2 system is broadly used for antifungal susceptibility testing of Candida spp., its performance against Candida auris has been assessed using limited number of isolates recovered from restricted geographic areas. We therefore compared Vitek 2 system with the reference Clinical and Laboratory Standards Institute (CLSI) broth microdilution method using an international collection of 100 C. auris isolates belonging to different clades. The agreement ±1 twofold dilution between the two methods and the categorical agreement (CA) based on the Centers for Disease Control and Prevention's (CDC's) tentative resistance breakpoints and Vitek 2-specific wild-type upper limit values (WT-ULVs) were determined. The CLSI-Vitek 2 agreement was poor for 5-flucytosine (0%), fluconazole (16%), and amphotericin B (29%), and moderate for voriconazole (61%), micafungin (67%), and caspofungin (81%). Significant interpretation errors were recorded using the CDC breakpoints for amphotericin B (31% CA, 69% major errors; MaEs) and fluconazole (69% CA, 31% very major errors; VmEs), but not for echinocandins (99% CA, 1% MaEs for both micafungin and caspofungin) for which the Vitek 2 allowed correct categorization of echinocandin-resistant FKS1 mutant isolates. Discrepancies were reduced when the Vitek 2 WT-ULV of 16 mg/L for amphotericin B (98% CA, 2% MaEs) and of 4 mg/L for fluconazole (96% CA, 1% MaEs, 3% VmEs) were used. In conclusion, the Vitek 2 system performed well for echinocandin susceptibility testing of C .auris. Resistance to fluconazole was underestimated whereas resistance to amphotericin B was overestimated using the CDC breakpoints of ≥32 and ≥2 mg/L, respectively. Vitek 2 minimun inhibitory concentrations (MICs) >4 mg/L indicated resistance to fluconazole and Vitek 2 MICs ≤16 mg/L indicated non-resistance to amphotericin B.

Re-cognition of adsorption phase density and adsorption phase volume: Insights from methane adsorption behavior

The determination of adsorption phase density significantly influences the assessment of gas occurrence state and gas content within in-situ reservoirs, particularly for the evaluation of gas content in deep coalbed reservoirs. Despite the extensive research on adsorption phase density, various calculation methods encounter limitations due to the inability to directly measure it. Simultaneously, the considerable disparity in results obtained from various adsorption phase density methods hampers the accurate determination of adsorbed gas and free gas content in deep coal seams. To address these challenges, this study systematically reviews calculation methods and highlights issues related to adsorption phase density. Considering practical experimental conditions, two new calculation methods are proposed: the adsorption potential adsorption phase density (APD) method and limit adsorption phase density (LAD) method. These methods enable the directional calculation of adsorption phase density based on the unknown or known absolute adsorption amount. The obtained results reveal that the adsorption phase density obtained through the APD method exhibits variations in temperature and pressure. For different coal rank samples, the range of actual adsorption phase density at different temperatures under high pressures is expected to fall between 0.30 g/cm3 and 0.40 g/cm3. The range can serve as a theoretical upper limit value for refining adsorption phased density models. The adsorption phase density acquired through the LAD method exhibits variations in temperature and pressure, whereas the adsorption phase volume remains unaffected by changes in temperature and pressure. The computed outcomes from the LAD method align with those derived from nuclear magnetic resonance (NMR), adsorption phase volume (APV), and molecular simulation methods, affirming the accuracy and applicability of the adsorption phase density determined via the LAD method. It is envisaged that these research findings will enhance the precise determination of adsorption phase density and assist in discerning the occurrence state of deep coalbed methane and, potentially, carbon dioxide sequestration.

Blood cadmium level and the change of cadmium exposure risk in Chinese urban school-age children in 2002 and 2012

To investigate the blood cadmium concentrations and the related change in Chinese urban children derived from the China Nutrition and Health Survey 2002 and 2012(CNHS 2002 and CNHS 2012). The Chinese urban children aged 6-11 years were selected according to gender, age and regional distribution using the multi-stage stratified cluster random sampling method, as well as the corresponding whole blood samples. The blood cadmium concentration was carefully determined by the quadrupole inductively coupled plasma mass spectrometry(ICP-MS) and the percentage of blood cadmium over 2 μg/L was subsequently estimated. In addition, the upper limit values of the 95%CI of the 95th percentiles of available blood cadmium data was assessed as the threshold of cadmium exposure. Totally, 2182 Chinese urban children were included, and of these, 1036 children were from the CNHS 2002 and 1146 children were from the CNHS 2012. From the CNHS 2002 to the CNHS 2012, the median blood cadmium concentration was increased from 0.28 μg/L to 0.95 μg/L, and the percentage of blood cadmium with over 2 μg/L was elevated from 1.45% to 10.47%. In addition, the new estimated threshold of blood cadmium was ascended from 1.24 μg/L up to 2.89 μg/L. The risk of cadmium exposure in Chinese urban children aged 6-11 years was increasingly aggravated from the CHNS 2002 to the CNHS 2012.