Direct Test Method Research Articles

Gradient diffusion antibiogram used directly on bronchial aspirates for a rapid diagnosis of ventilator-associated pneumonia

BackgroundIn patients with suspected ventilator-associated pneumonia, a rapid etiological diagnosis is crucial as incorrect or delayed treatment in the first few hours leads to a worse prognosis and a higher mortality rate. This study examines the efficacy of a rapid antibiogram on bronchial aspirates in patients with suspected ventilator-associated pneumonia (VAP).MethodsThe direct gradient diffusion susceptibility testing method (GDM) on respiratory samples was compared with a standard broth microdilution method (BMD) after quantitative cultures in patients with suspicion of VAP. Samples were preselected by Gram staining (for good quality microbiological samples with a predominant single bacterial morphotype). The antibiotics tested were ceftazidime, ceftobiprole, ceftolozane-tazobactam, meropenem, doripenem, and tedizolid.ResultsOver a 16-month study period, 445 bronchial aspirate samples were selected from 1376 samples received at our laboratory from 672 adult patients. By direct plating on Mueller-Hinton agar, we recovered 504 (95.5%) of the 528 microorganisms identified by the standard semiquantitative method. Antimicrobial susceptibility testing by GDM was compared with the BMD method in 472 strains (216 Enterobacteriaceae, 138 P. aeruginosa and 118 S. aureus.) and 1652 individual microorganism-antimicrobial agent combinations. There was total agreement between both methods in 98% of combinations. The Kappa index between both techniques was excellent (over 80%). There was only one potential major error for P. aeruginosa susceptibility to ceftazidime.ConclusionsThe six GDM strips directly placed on plated bronchial aspirates obtained from patients with a suspicion of VAP provided accurate and reliable susceptibility results within 24 h.

Identification of Novel Microsatellite Markers Flanking the SMN1 and SMN2 Duplicated Region and Inclusion Into a Single-Tube Tridecaplex Panel for Haplotype-Based Preimplantation Genetic Testing of Spinal Muscular Atrophy.

Preimplantation genetic testing for the monogenic disorder (PGT-M) spinal muscular atrophy (SMA) is significantly improved by supplementation of SMN1 deletion detection with marker-based linkage analysis. To expand the availability of informative markers for PGT-M of SMA, we identified novel non-duplicated and highly polymorphic microsatellite markers closely flanking the SMN1 and SMN2 duplicated region. Six of the novel markers within 0.5 Mb of the 1.7 Mb duplicated region containing SMN1 and SMN2 (SMA6863, SMA6873, SMA6877, SMA7093, SMA7115, and SMA7120) and seven established markers (D5S1417, D5S1413, D5S1370, D5S1408, D5S610, D5S1999, and D5S637), all with predicted high heterozygosity values, were selected and optimized in a tridecaplex PCR panel, and their polymorphism indices were determined in two populations. Observed marker heterozygosities in the Chinese and Caucasian populations ranged from 0.54 to 0.86, and 98.4% of genotyped individuals (185 of 188) were heterozygous for ≥2 markers on either side of SMN1. The marker panel was evaluated for disease haplotype phasing using single cells from two parent–child trios after whole-genome amplification, and applied to a clinical IVF (in vitro fertilization) PGT-M cycle in an at-risk couple, in parallel with SMN1 deletion detection. Both direct and indirect test methods determined that none of five tested embryos were at risk for SMA, with haplotype analysis further identifying one embryo as unaffected and four as carriers. Fresh transfer of the unaffected embryo did not lead to implantation, but subsequent frozen-thaw transfer of a carrier embryo produced a pregnancy, with fetal genotype confirmed by amniocentesis, and a live birth at term.

Fabrication of pH-responsive TA-keratin bio-composited hydrogels encapsulated with photoluminescent GO quantum dots for improved bacterial inhibition and healing efficacy in wound care management: In vivo wound evaluations

Wounds origins serious complications of lives of human beings which may leads to death. The important issue for the problem is infection during wound care management which delays wound healing process. These kinds of infections may be caused by the overuse or misuse of antibiotics, antidotes, usage of new drugs, not properly sterilized surgical instruments, not appropriate for pH level and imperfect wound dressing etc. during or after surgery. Hence in this report, antimicrobial action of pH responsive TA/KA composited hydrogel crosslinked with GO-QDs (TA/KA-GOQDs) using citric acid as cross-linker has been reported by demonstrating in-vitro and in-vivo studies for wound care management. The prepared samples of GOQDs, TA/KA hydrogel and TA/KA-GOQDs were characterized using FT-IR, XRD, SEM and TEM techniques. pH responsive hydrogel property of TA/KA was evaluated by swelling studies. In-vitro antibacterial studies was carried out by direct contact test method. Further, the prepared samples were tested in a wound healing model of rate with the wound of size 1.5 cm2 for in-vivo studies. After 16 days of treatment, the prepared samples for wound healing causes 100% wound areas closure. Histological observations were made by MT and HE staining process which proves keratinocytes proliferation by biocompatible and biocomposited TA/KA-GOQDs. The pH responsive TA/KA-GOQDs proved as efficient wound healing agent by faster keratinocytes proliferation within a compact period.

The emerging role of serum zinc in motor disability and radiological findings in patients with multiple sclerosis

BackgroundThe role of serum Zinc in the pathogenesis of relapsing remittent multiple sclerosis (RRMS) and its impact on motor disability and radiological findings remains a matter of debate.ObjectivesTo assess the level of serum Zinc in patients with RRMS at time of relapse and during remission and to correlate serum zinc with degree of disability, fatigue, response to disease modifying drugs, and magnetic resonance imaging (MRI) findings.Subjects and methodsA case-control study was carried out on 75 subjects divided into three groups, 25 patients diagnosed as RRMS during relapse, 25 patients during remission, and 25 healthy controls. All included patients were subjected to neurological assessment including Expanded Disability Status Scale (EDSS), Modified fatigue impact scale (MFIS), and Modified RIO score (MRS). Zinc serum level was measured for all patients and controls using direct colorimetric test method. Brain and spine MRI were done for all included patients.ResultsMS patients in relapse and during remission were found to have significantly lower zinc level than the control group (P value = 0.001 and < 0.001 respectively). There was a statistically significant negative correlation between serum zinc level and disease duration, number of relapses in the last 2 years, total number of relapses, EDSS before and after pulse steroids, MRS, MFIS, and MRI lesion load (P value = 0.017, 0.037, 0.001, 0.001, 0.004, 0.005, and 0.001, respectively).ConclusionSerum zinc level is significantly lower in patients with MS than healthy controls. It is negatively correlated with disease duration, number of relapses, motor disability, fatigue, and MRI lesion load.

Investigation of the Soil-Geosynthetic Interaction Using Direct Shear Testing and FEM Method

Verification of the design of the reinforced earth retaining structures is usually based on the global and internal stability check. Beside the analytical solutions, numerical modelling can simulate the real behaviour of the structure including mutual interaction of the particular elements. Additionally, stress-strain relation is involved in the final verification together with the required stability of the system. Parameters such as reinforcement stiffness or interaction ability with the soil allow to calculate more realistic axial forces acting in the reinforcing elements. Analytical solutions don’t take into account the influence of the deformation of the soil mass on the overall and internal stability. Finite Element Method can describe both of these mechanisms which take place simultaneously. Estimation of the interaction parameters is crucial to determine the forces with sufficient accuracy, especially when 2nd limit state is critical for the structure design. The paper is aimed at the laboratory testing and numerical modelling of the interaction of the geosynthetic reinforcement and the soil during the sliding described by the interaction coefficient. A direct shear test was adopted to investigate the actual value of the interaction coefficient which is related to the certain displacement of the reinforcement in the soil. There is a recommendation not to use the interface element at the soil-reinforcement contact when the grid shaped reinforcing elements such as geogrids are used for the numerical simulations. This approach was approved by the study presented in this paper. Reinforcement with the grid structure and rigid joints provides higher level of interaction with the soil environment so reduction of the shear strength at this contact is unrealistic.

ACCEPTANCE OF OWN CORPOREALITY IN THE CONTEXT OF THE DEVELOPMENT OF MARITAL RELATIONSHIPS: CONTRADICTIONS AND THEIR RESOLUTION

The article states the biopsychosocial approach as providing an opportunity to cover different aspects of the psychology of corporeality in the sphere of marital interaction. The results of the study relate to the gender differences in the attitude of the married couples to their own body, in particular, in the categories of «acceptance-rejection» and its presentation in marital interaction through the concept of «criticism of the appearance of the partner» and «motivation to change one’s own body». Participants of the study are300 persons aged from 19 to 75 years old. The research was conducted by the method of direct and on-line testing. According to the results of the research, which was conducted on the territory of Ukraine, the antonymic nature of corporeality in the context of married life was confirmed, and it was statistically proved that positive attitude towards one’s own body is a condition of positive perception of the world, prosociality and satisfaction with family life as a whole and with each one of its spheres. It is stated that the attitude towards one's own body is a situational characteristic that is variable throughout life. It was found that in situations of criticism of the appearance on the part of the partner, the initially fixated positive attitude to one’s own body undergoes a revision (up to its destruction). The reactive character of the motivation for changes in one's own body is being proved: conflicting, antagonistic and criticizing environment enhances the motivation to change one’s own body and is more characteristic for women under the age of 30 without children. The research has found the effects of restoring a positive attitude towards one's own body. They relate to situations of manifestations of sociability and support of the partner as a response to a request; development of the sphere of interests that are sociable and promisingly directed for environmentally friendly management of the living environment. It is proved that the positive attitude towards one’s own body is based on the relationship of mutual support, interest in food and mode of life, thereby pointing to directions of development of the culture of marital relationships. The prospect of further research is the study of the nature of corporeality as a systemic and cultural phenomenon, which reveals the marital potential of balanced functioning in the living environment.

Behaviour of hybrid steel fibre reinforced self compacting concrete using innovative hooked-end steel fibres under tensile stress

The use of steel fibre hybridisation with different aspect ratios have been seen to enhance the pre and post cracking response of concrete, however the invention of new innovative macro hooked ends steel fibres with multiple hooks and increase in its linear length have been recently investigated. The results show that the new innovative macro hooked ends steel fibre with multiple hooks performed better than single hooked ends steel fibre with respect to material properties when used in self-compacting concrete. Therefore, the need to further investigate the performance of this new innovative macro (MAC) hooked ends steel fibre when combined with straight micro (MIC) steel fibre of the same aspect ratio in self-compacting concrete would be useful in the study of the stress-strain curve relationship of this composite material.A laboratory investigation on two different conditions of steel fibre hybridisation using straight MIC steel fibre (Length 13 mm and diameter 0.2 mm) with two different types of hooked ends MAC steel fibres, Single (S1) and Double (M2) hook(s) at 0.75% and 1% fibre content respectively. These are optimised values from previous experiments (laboratory tests conducted using different macro steel fibres at 0.25%, 0.5%, 0.75% and 1% fibre content). The Uniaxial direct tension test method is used. The results show that steel fibre hybridisation decreased workability due to the influence of the micro steel fibre content irrespective of the hooked ends steel fibre type. The use of Single hook (S1) macro hooked end steel fibre in steel fibre hybridisation further improved the material properties (compressive strength, tensile strength and fracture energy) when compared to the use of only macro hooked end steel fibre. However a decrease in the fracture energy is observed when Double hooks M2 macro hooked end steel fibre is used. Although positive results are seen with respect to other properties.

Bearing capacity of steel thin-walled profiles in reliability assessment

The increasing use of light steel thin-walled structures is determined by the efficiency of the production of cold-formed profiles. However, there are problems of calculating the reliability of thin-walled structures. In particular, it is necessary to specify the calculation of the generalized bearing capacity of an element from a thin-walled profile. Such an element is significantly affected by the initial geometric imperfections reducing its bearing capacity. At the same time the element is influenced by an uneven distribution of the mechanical characteristics of the steel over the section of the profile. A thin-walled element of paired sigma profiles with a section height of 300 mm was taken as the object of study. This paper presents the results of the calculation of the effective characteristics of a thin-walled profile operating under axial compression with bending without and with the initial geometric imperfections (additional eccentricity from the element’s initial curvatures). Besides, the paper reveals the results of laboratory studies of the distribution of the mechanical properties of steel over the cross section of a thin-walled profile after using direct and indirect test methods.

Characterization of peak shear strength of rough rock joints using limited displacement multi-stage direct shear (LDMDS) tests

Current standard direct shear test methods for rock joints do not account for damage to the specimens' asperity profiles; tests require shearing of a single specimen to large displacements under successive normal stresses (the multistage test), or the use of similar specimens in multiple tests. Due to the inherently unique nature of rock joints and corresponding difficulty in obtaining specimens with identical or even similar geometries, multistage tests are more common. A major issue with the multistage test is that successive shearing of the specimen damages the surface asperities and changes its overall roughness profile, reducing the peak shear stress and consequently resulting in underestimation of the friction angle and overestimation of the joint shear intercept (cohesion). The limited displacement multistage direct shear (LDMDS) test method minimizes these testing imperfections by allowing shearing of a single specimen without extensive asperity damage, accomplished by immediately pausing shear displacement once peak shear stress has been reached, then proceeding to shear the specimen under the following normal stress value, and shearing into the post-peak region only after identifying multiple values of peak shear strength. The authors have validated the LDMDS procedure using cement replicates of rock joints, demonstrating that it yields more accurate strength parameters than the standard multistage direct shear test.

Determination of the Direct Tensile Strength of Granite Rock by Using a New Dumbbell Shape and its Relationship with Brazilian Tensile Strength

In this study, the determination of the direct and indirect tensile strength of granite rock was carried out in compliance with related standard test methods. In order to analyze rock tensile strength between direct (with using a new dumbbell shape) and indirect (Brazilian tensile strength) test methods were conducted and obtained results were compared between them. A new dumbbell shape samples were used in direct tensile tests and cylindrical specimens, which have different t/D ratios such as 0.5, 0.75, and 1.0, were used in Brazilian tests. Moreover, stress distribution and the stress intensity within the sample were analyzed with Finite Elements Method (FEM) and numerical modeling techniques by using ANSYS R18 software. The direct tensile test yielded lower strength values than the indirect test. For the specimens tested in direct tensile test, failure occurred middle of the dumbbell shape sample due to lower stress intensity factor. Since Brazilian disc test, stress value in the diametrical line of the specimen has been found higher than nominal stress value according to FEM, tensile strength value that should be re-calculated by using any coefficient. Moreover, t / D ratio did not affect the Brazilian test results.

Evaluation of direct drug susceptibility testing of blood culture isolates comparing it with conventional disk diffusion testing.

To evaluate a direct antibiotic susceptibility testing method for blood culture.. The cross-sectional comparative study was conducted at the Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from December 2016 to October 2017. Direct antimicrobial susceptibility testing was performed from positive blood culture bottles. Bacterial identification was done by using API 10S. Different antimicrobial panels were employed for Gram-negative rods (GNRs), gram-positive cocci (like suspected Staphylococci and Enterococci). Results were compared with conventional disk diffusion testing and very major, major and minor errors were calculated. Result agreement and kappa coefficient scores were generated for categorical agreement. SPSS 24 was used for data analysis. Of the 101 bacterial isolates, 82(81.2%) were Gram negative rods and 19(18.8%) were Grampositive cocci. Among 781 bacteria-antibiotic comparisons, the number of very major errors was 3(0.4%), major errors were 7(0.9%) and minor errors were 12(1.5%), while, 759(97.2%) comparisons yielded the same results. The kappa coefficient was 0.946, showing almost perfect agreement. Direct identification of Gram negative rods was successful in 53(64.6%) cases. Direct susceptibility testing of blood culture produced reliable results for majority of the antimicrobials.

Portable Electric Hoist for Effectiveness of Construction of 3rd Floor Houses

The development of a city can be measured by the amount of development that has been carried out and its suitability for people needs, which is seen by the increase of demand for Building Construction Permits (IMB certificate) because around 70% of regional income is derived from levies in this sector. The population density of a residential area is no longer possible developed by horizontally, along with the increase in the needs of dwellings and businesses to meet the needs of the construction of houses and businesses by building them in 3rd floor houses Lifting equipment type portable electric hoist is a tool which used to move material from the first floor to the next floor during the construction of 3rd floor houses. The transferred material includes; bricks, ceramics, cement, and other building materials. This research conducted to analyze the design of a Lifting Equipment for Material type portable electric hoist to increase the effectiveness of the construction of 3rd floor houses. This study uses a direct load testing method by lifting up to the maximum test load or tipping load. Lifting and moving of test loads is determined at an altitude of 5 meters and 12 meters from the ground floor surface The results of this research indicates that the five stages load carried out by lifting and moving materials test loads by the design of a portable electric hoist were accepted. Lifting and moving load at sixth floor is rejected because condition of tipping. The rejection of the results from this test became a reference to determine the maximum safe working load for operational design of portable electric hoist only 300 kilograms

Damage Characteristics of CFRP Laminates Subjected to Multiple Lightning Current Strike

The lightning damage depths and areas of carbon fiber reinforced polymer (CFRP) laminates subjected to multiple continuous sequential lightning current components with different timing combinations were experimentally evaluated. The experimental results indicated that the CFRP laminates suffered serious lightning damage, including fracture of the carbon fibers and layer delamination. After a multiple lightning strike composed of lightning components A, B and C, the surface temperature of the CFRP laminates, which was projected from the measured temperature with lower magnitude, can exceed 1600 °C. The damage area and depth were approximately 2790 mm2 and 1.28 mm in the “ABCD” test mode. The damage depth was found to be closely related to lightning components A, B and D, which are accompanied by the shockwave and the overpressure effect, the dielectric breakdown effect and the local thermal effect. The increases in the surface temperature and damage area after lightning strike were mainly affected by the lightning component C with substantial thermal effect. The application sequence and material properties are important factors for evaluating the damage effect of the newly added lightning component on samples that have suffered from multiple continuous lightning components. The influencing factors and analysis method for CFRP laminate lightning damage subjected to multiple continuous sequential lightning components may provide both experimental support and a theoretical basis for studying the mechanism of the lightning effect and the refinement and improvement of a lightning direct effect test method for CFRP laminates in the future.

An introduction to a new direct testing method for characterizing pressure in compression fabrics

A newly developed direct pressure measuring system known as the CRIM Pressure System was compared with a traditional direct measuring device, the PicoPress Compression System, for compression bandage and hosiery samples. PicoPress measurements were taken both on the CRIM system and on research participants. Initial results indicated a good correlation between CRIM Pressure System and PicoPress participants’ measurements.

A Tensile Strength Apparatus with the Facility to Monitor Negative Pore-Water Pressure

Abstract This article presents a new testing method for investigating the behavior of clayey geomaterials subjected to a tensile (negative) total stress. The method includes the use of high-capacity tensiometers to measure the pore–water pressure of the test specimen, an aspect which has not been demonstrated in any other direct tensile testing method. This addition allows interpretation of failure data in terms of effective stress rather than total stress, which is the approach that should be pursued in the saturated range. The test specimen shape and loading method have been modified from those commonly seen in existing literature to ensure that the direction of the major principal stress in the failure zone coincides with the direction of the externally applied tensile force, allowing for a more accurate analysis of tensile failure. Results are shown for saturated specimens and compared to results obtained for the same soil in uniaxial compression, using a modified version of the presented uniaxial tensile method, and a triaxial compression test. It is demonstrated that crack initiation occurs by shear failure if the data are interpreted in terms of effective stress rather than total stress and that the failure mechanisms under tension do not differ from compression.

A method for calculating the carbonation degree of calcium–silicate–hydrate

The carbonation degree of calcium–silicate–hydrate (CSH) was quantitatively characterised using a direct test method. Nuclear magnetic resonance (NMR) and thermogravimetric methods were used to study different depths of cement paste with a water/cement ratio of 0·35 after 28 d of carbonation. Firstly, based on the hydration and carbonation reaction equations of the CSH, the variation of Ca2+can be obtained, and then according to the variation of Ca2+to calculate the carbonation degree of CSH. Secondly, the parameter I(Q2)/I(Q1) was determined to characterise the structural change of the CSH quantitatively. Finally, the relationship between the CSH carbonation degree and I(Q2)/I(Q1) was analysed. The results showed that the carbonation degree of CSH can be expressed as the ratio of the molar content of calcium carbonate carbonated by CSH and the molar content of Ca2+in the initial CSH. A good linear relationship was found between the value of I(Q2)/I(Q1) and the CSH carbonation degree. Therefore, the NMR method can be used to determine the carbonation degree of CSH.

Friction coefficient between FRP pultruded profiles and concrete

This paper presents the experimental results of a direct shear test to determine the friction coefficient between fibre reinforced polymer (FRP) pultruded profiles and concrete. The FRP pultruded profile used in this study was glass fibre reinforced polymer (GFRP) I-section. The specimens were composed of a concrete block and a coupon of the GFRP pultruded profile. The experiment was conducted by using the direct shear test method. The parameters investigated included the type of concrete (self-compacting concrete and normal concrete) and the compressive strength of the concrete, as well as the different components (web and flange) of the I-section. The test results verify that the bond behaviour between the concrete and the GFRP pultruded profiles mainly depends on two factors, the friction stress and the adhesion stress. The friction coefficient between the FRP pultruded profiles and the concrete was between 0.5 and 0.6 when the normal stress fluctuated between 0.5 and 2 MPa, and the adhesion stress was about 0.2 MPa. The compressive strength of the concrete and the different components of the I-section have little effect on the friction coefficient, however, the type of the concrete significantly affects this coefficient.

Direct tension behaviour of steel fibre reinforced concrete measured by a new test method

A new direct tension test method of applying tension to a dumbbell-shaped specimen through side-glued steel plates at the end blocks for measuring the tensile stress-strain characteristics of fibre reinforced concrete (FRC) was developed. Finite element analysis of the test setup revealed substantially reduced stress concentration in the specimen. The new method was applied to test FRC specimens made with four different types of hooked steel fibres. It was found that both the first cracking strength and post cracking strength increased with the fibre volume but at different rates for the different types of steel fibres. From the stress-strain curve, two different values of tensile strain capacity, one defined as the tensile strain at maximum tensile stress and the other defined as the tensile strain at which the tensile stress dropped to 80% of cracking stress, were obtained. Regression analysis of the test results yielded good correlations to the fibre factor and empirical formulas for estimating the minimum fibre factor for strain hardening and the tensile strain capacities.

Durability of ultra-high performance concrete in tension under cold weather conditions

Freezing and thawing resistance is a key characteristic for concrete materials in cold weather conditions. In this study, the tensile properties and elastic modulus of ultra-high performance concrete (UHPC) under accelerated freeze-thaw cycles are characterized. Six series of UHPC specimens are experimentally tested with a well-designed direct tension test (DTT) method to capture complete tensile stress-strain responses. Both the dynamic and wave moduli of elasticity of UHPC are measured at specific cycles using the standard impact test and self-designed “smart aggregate” technology, respectively. Long term freezing and thawing cyclic conditioning of UHPC samples results in reductions of elastic modulus, tensile strength, strain capacity, and energy absorption capacity. The tensile stress-strain curves of UHPC demonstrate distinct descending with increasing freeze-thaw cycles, particularly in the strain softening region. The energy-based approach is found to be more sensitive and effective than the elastic modulus-based approach when evaluating material deterioration over time and capturing accumulative material degradation subjected to rapidly-repeated freezing and thawing actions. As from the test results, UHPC is characterized as a very durable cementitious material, but it is not inherently unconquerable. Extended freezing and thawing actions can still lead to deterioration of the material, with respect to its elastic modulus, tensile strength, energy absorption capacity, etc. As demonstrated, the DTT method can be used to effectively characterize the long-term performance of UHPC in tension under cold weather conditions.

Testing the Test: Expanding the Dialogue on Technical Writing Assessment in the Academy and Workplace

The small amount of work on workplace writing assessment has focused almost entirely on student readiness for professional writing or included case studies of employer expectations for new writers. While these studies provide insight into current pedagogies for technical writing and writing instruction in general, the main conclusion to be drawn from them is the unsatisfactory number of recent graduates who display workplace readiness. In this article, we explore writing assessment research in both the academy and the workplace and attempt to identify ways in which the academy’s assessment practices lead, lag behind, or simply differ from writing assessment in the workplace. This comparison will serve to identify not only where the academy might improve pedagogy in its curriculum for technical communication in order to best prepare students for workplace writing but also where the workplace might learn from the academy to improve its own hiring and training procedures for technical writers. In this case study, we used Neff’s approach to grounded theory to categorize rater feedback according to a ranking system and then used statistical analysis to compare writer performance. We found that the direct test method yields the most predictive results when raters combine tacit knowledge with a clearly defined rubric. We hope that the methods used in this study can be replicated in future studies to yield further results when exploring workplace genres and what they might teach us about our own pedagogical practice.