Existing Laboratory Methods Research Articles

Digital Core Modelling for Clastic Oil and Gas Reservoir

"Digital core" is a multi-purpose tool for solving a variety of tasks in the field of geological exploration and production of hydrocarbons at various stages, designed to improve the accuracy of geological study of subsurface resources, the efficiency of reproduction and use of mineral resources, as well as applying the results obtained in production practice. The actuality of the development of the "Digital core" software is that even a partial replacement of natural laboratory experiments with mathematical modelling can be used in the operative calculation of reserves in exploratory drilling, as well as in the absence of core material from wells. Or impossibility of its research by existing laboratory methods (weakly cemented, loose, etc. rocks). 3D-reconstruction of the core microstructure can be considered as a cheap and least time-consuming method for obtaining petrophysical information about the main filtration-capacitive properties and fluid motion in reservoir rocks.

FLECS Technology for High-Throughput Single-Cell Force Biology and Screening.

Dr. Ivan Pushkarsky from the Department of Bioengineering at UCLA and Forcyte Biotechnologies, Inc. was awarded The President's Innovation Award at the Annual Society of Biomolecular Imaging and Informatics meeting held in San Diego, September 2017. All cell types produce mechanical forces to serve important physiological roles. Since aberrant force-generating phenotypes directly lead to disease, cellular force-generation mechanisms are high-value targets for new therapies. Despite knowledge of their significance in disease, drug developers have had limited access to force-generating cellular phenotypes, especially in the context of high-throughput screening. To serve this valuable need, we have developed a platform microtechnology called "FLECS" that can acquire robust contractility data from 1000s of uniformly patterned single cells simultaneously and seamlessly integrates with the 96- and 384-well plate formats to facilitate large-scale drug screens. This perspective discusses the challenges facing existing laboratory methods for measuring cellular force in the context of drug discovery. It then provides an overview of the FLECS platform, describes how it was designed to overcome many of these challenges, and discusses some exciting work already accomplished with FLECS. It concludes by highlighting the platform nature of the technology and the potential value that it promises for a myriad of drug development efforts.

Spectral absorption by marine chromophoric dissolved organic matter: Laboratory determination and piecewise regression modeling

Chromophoric dissolved organic matter (CDOM) is an important light-absorbing component of seawater. Yet spectrophotometric determinations of CDOM absorption from existing laboratory methods differ substantially. Since CDOM absorption in the visible usually remains below the detection limit of traditional spectrophotometers, its spectral shape has been modeled from the ultra-violet, by applying a single exponential model (SEM) from which a unique parameter, the spectral slope S, is derived. The usefulness of SEM and S is controversial, due to the lack of agreement on the fitting procedures and the poor ability of the SEM to fit equally well all CDOM absorption spectra. In view of this, empirical factors affecting the measurement of CDOM absorption coefficient by spectrophotometry were tested. No differences in CDOM spectra obtained by filtration through 0.2 μm membrane or 0.7 μm GFF filters were found for either high (Case II) or low (Case I) CDOM content situations. Two spectral shape groups were distinguished after applying a multivariate approach to 145 spectra from the South Atlantic, Strait of Magallanes, and South Pacific. The two groups were associated mainly with coastal and oceanic waters. A segmented regression model (SRM) with two free breakpoints better represented the CDOM absorption spectra than a SEM. The SRM fitted both CDOM spectral shape groups with accuracy. This concatenated exponential model is useful for understanding CDOM dynamics and developing improved satellite ocean-color algorithms.

PP.33.10] AMBULATORY HEMODYNAMIC TRENDS IN HYPERTENSION AND AGING

Objective: To compare 24-hour ambulatory blood pressure monitoring with existing laboratory methods, and to investigate the impact of BP and age on systemic hemodynamics. Design and method: Cardiac output (CO) and systemic vascular resistance (SVR) were analyzed in 3 sub studies. Sub study A: 24-hour PWA (MobilOGraph, IEM, Stolberg, DE) was performed in a convenience sample (n = 66) stratified into 3 groups by systolic BP levels (<120, 120–139, >139 mmHg) and separately stratified by age (<55, >/ = 55 years). Sub study B: Each individual PWA was analyzed for within individual trends in CO and SVR. These trends were compared to the trends obtained from Sub study A. Sub study C: supine hemodynamics and echocardiographic parameters measured in a reference population developed in our laboratory (n = 78) were compared to 24-hour PWA means(Sub study A). Results: BP was independent of CO in all 3 sub studies, overall and for each BP subgroup. Thus, there are very strong inverse relationships between 24-hour SVR and 24-hour CO for each BP group (p < 0.000 each) in each sub study, with a parallel upward-rightward shift of the respective SVR-CO isobars as BP increases. Figure 1 (left panel) shows the SVR-CO isobars for each BP group in Sub study A. Nearly identical relationships were also found in sub studies B and C. Figure 1 (right panel) demonstrates respective SVR-CO isobars for younger and older individuals, demonstrating only a rightward shift in the SVR-CO isobar.Conclusions: 1) Hemodynamic analysis using 24-hour ambulatory PWA is feasible. 2) Sustained hypertension is associated with an upward-rightward shift of the SVR-CO isobar in proportion to the degree of BP elevation, indicating that the underlying hemodynamic abnormality in hypertension at any stage is both inappropriately high CO and inappropriate high SVR. 3) Age effects on hemodynamics are more complex.

Molecular Detection of Diarrheal Pathogens

Acute diarrhea is an extremely common illness and causes a spectrum of disease, from loose bowel movements to severe dehydration and death. Most cases of acute diarrhea, and a proportion of chronic diarrhea cases, are associated with infections or their toxins, yet current diagnostic strategies are complex, time-consuming, and generally unproductive. Uniplex assays for bacteria such as Clostridium difficile or Shiga toxin-producing Escherichia coli are quicker than culture and more sensitive than antigen-based methods, while molecular methods for viral targets have largely replaced electron microscopy or antigen detection. Commercial multiplex panels are now available for viral, bacterial, and protozoal pathogens. Panels differ by included analytes, pre-analytic requirements, processing (on demand versus batch), and instrumentation. Uniplex or limited multiplex panels may complement existing laboratory methods, whereas more comprehensive multiplex panels may replace antigen detection and culture altogether. However, culture will still be needed for epidemiologic characterization and for antimicrobial susceptibly testing.

Laboratory Methods for Determining Etiology of Neonatal Infection at Population-based Sites in South Asia: The ANISA Study.

The Aetiology of Neonatal Infection in South Asia (ANISA) study aims to determine the etiology of neonatal infections in 5 population-based sites in Bangladesh, India and Pakistan. The main laboratory challenges in ANISA were selection and consistent implementation of laboratory methods at participating sites with varied infrastructure. The other specific challenges included (1) specimen collection and transport to designated study laboratories and timely processing in rural settings; (2) minimal or nonexistent laboratory facilities at the field sites; (3) obtaining sufficient volumes of blood from enrolled infants aged 0-59 days and (4) caregivers' concerns about collection of clinical specimens from young infants. An additional challenge was selecting an appropriate molecular platform from multiple available options, all with limited field validation, for use in determining infection in young infants. This article describes how the challenges of specimen collection, transport and processing and implementation of laboratory methods have been addressed in the ANISA study. It also describes the measures taken to improve detection of microorganisms causing young infant infections by enhancing the sensitivity of existing laboratory methods for pathogen detection.

Review of laboratory-based terrestrial bioaccumulation assessment approaches for organic chemicals: Current status and future possibilities.

In the last decade, interest has been renewed in approaches for the assessment of the bioaccumulation potential of chemicals, principally driven by the need to evaluate large numbers of chemicals as part of new chemical legislation, while reducing vertebrate test organism use called for in animal welfare legislation. This renewed interest has inspired research activities and advances in bioaccumulation science for neutral organic chemicals in aquatic environments. In January 2013, ILSI Health and Environmental Sciences Institute convened experts to identify the state of the science and existing shortcomings in terrestrial bioaccumulation assessment of neutral organic chemicals. Potential modifications to existing laboratory methods were identified, including areas in which new laboratory approaches or test methods could be developed to address terrestrial bioaccumulation. The utility of "non-ecotoxicity" data (e.g., mammalian laboratory data) was also discussed. The highlights of the workshop discussions are presented along with potential modifications in laboratory approaches and new test guidelines that could be used for assessing the bioaccumulation of chemicals in terrestrial organisms.

Current standards for diagnosis of syphilis: comparing the russian and foreign guidelines (part I)

Despite the abundance of existing laboratory methods the diagnosis of syphilis still faces many challenges. Though direct detection of T. pallidum plays an important role in early manifest forms of the disease, serological tests remain the mainstay of diagnosis. Traditional syphilis screening algorithm based on nontreponemal tests with subsequent confirmation using treponemal tests is a standard worldwide. Recently, the ability to automate the treponemal tests promotes the increasingly widespread implementation of reverse algorithm when these tests are used for syphilis screening. None of the current serological algorithms are able to reliably differentiate between active and previously treated syphilis, which causes uncertainty in the management of patients. There is no «gold standard» for the diagnosis of neurosyphilis, ocular, auricular and visceral syphilis. The interpretation of serological tests in children born to seropositive mothers is also complicated. Diagnosis of congenital syphilis in newborns and, consequently, the prescription of antibiotic therapy often depends on assessment of the adequacy of maternal treatment during pregnancy, which leads to subjective decisions. This article provides a comparative analysis of the «Federal guidelines for the management of patients with syphilis» and their foreign analogues, discusses significant peculiarities of these guidelines and reviews current concerns and controversies in syphilis diagnosis.

Profertility effects of aqueous leaf extract of Telfairia occidentalis in adult male Wistar rats

Telfairia occidentalis is a leafy vegetable consumed commonly for its nutritional and medicinal effects. However, few studies have been carried out on its fertility effects in males with most of such studies offering conflicting results. The present study evaluated the effects of aqueous extract of the leaves of T. occidentalis on male fertility in adult wistar rats. The thirty rats used for this study were randomized into groups A, B and C. Rats in groups B & C were treated with 500 and 1000mg/kg.bwt of the leaf extract respectively by gavage for 56 days while group A served as control. The sperm characteristics, male hypothalamo-pituitary gonadal axis hormones and histological studies were carried out according to existing laboratory methods. Results from all the parameters studied showed that the aqueous extract of leaves of T. occidentalis exhibited profertility properties in adult male wistar rats. Further research to determine the components of the leaf extract implicated in the outcomes observed and the mechanism of action would be necessary. Keywords: Profertility, Telfairia occidentali s, Wistar rats

Short-wavelength infrared spectroscopy of chlorite can be used to determine very low metamorphic grades

This study investigates the use of short-wavelength infrared reflectance spectroscopy for measuring chlorite physicochemical information of value for determination of very low metamorphic grades. The method is termed chlorite spectral index (CSI) and assessed through quantitative comparison with XRD-derived Arkai and Kubler indices (AI and KI, respectively) in a set of 41 pelitic samples. The four CSI measures investigated measure the depth (D) of the absorption features at 1900, 2250 and/or 2350 nm, and are defined as reflectance 2250D/1900D index (CSI(H 2 O)), reflectance (2350D + 2250D × 1.7)/1900D index (CSI(H 2 O) sum ), reflectance 2250D index (CSI(2250)) and reflectance 2350D + 2250D × 1.7 index (CSI sum ). The results demonstrate the applicability of the method: all CSI measures show a good correlation with the AI, and respective correlation factors range between R 2 = 0.840 (for the CSI(H 2 O)) and R 2 = 0.616 (for the CSI sum ). The CSI measures also show a good correlation with the KI with R 2 = 0.704 (for CSI sum ) to 0.769 (CSI(2250)). By applying the correlation equations to define the metamorphic zone boundaries for each of the CSI measures, 64.3–78.6 % of the samples match the metamorphic grade indicated by AI for the epizone, 47.1–70.6 % for the anchizone and 70–80 % for the diagenetic zone. All CSI measures show a good reproducibility, with an intra sample variance ranging between 2.31 % CSI(H 2 O) sum and 3.34 % (CSI(2250)). CSI is not restricted to pelitic rocks and marls, but can also be applied in very low-grade metabasites. In addition to the existing laboratory method, CSI has application potential in remote sensing applications.

Update: Thrombozytopathie/Thrombocytopathy: an update

Zusammenfassung Der Begriff Thrombozytopathie bezeichnet angeborene oder erworbene funktionelle Störungen der Thrombozytenfunktion. Aufgrund der Vielzahl von möglichen pathophysiologischen Ursachen, basierend auf der Komplexität thrombozytärer Funktionsabläufe und Stoffwechselprozesse, zeigen Thrombozytopathien eine außerordentlich hohe klinische Variabilität. Eine Abbildung der Pathophysiologie ist mit den verfügbaren labordiagnostischen Verfahren nur sehr eingeschränkt möglich, da sich für verschiedene Thrombozytopathien sehr variable Sensitivitäten und Spezifitäten ergeben. Nicht zuletzt wird die Interpretation durch die hohe intraund interindividuelle Variabilität der Thrombozytenfunktion erschwert. In der Routine-Abklärung von Thrombozytopathien stehen eine detaillierte Anamnese und klinische Untersuchung in Kombination mit aggregometrischen Basisverfahren weiterhin im Vordergrund.

Thrombocytopathy: an update1

Abstract “Thrombocytopathia” describes inherited or acquired functional disorders of platelets. The complexity of functional and metabolic processes in platelets is associated with a multitude of possible pathologic disturbances, showing a high variability in the clinical picture. The diagnosis of thrombocytopathies by existing laboratory methods is limited by variable sensitivities and specificities for various pathophysiologic backgrounds. Furthermore, the clinical evaluation of laboratory results is complex because of high intra- and interindividual variability of the platelet function. In daily routine diagnostics, a detailed patient history and clinical examination combined with aggregometry-based laboratory methods remains the central approach to diagnose a platelet function disorder.

A validated hybrid quadrupole linear ion-trap LC–MS method for the analysis of morphine and morphine glucuronides applied to opiate deaths

A hybrid quadrupole linear ion-trap mass spectrometer using an electrospray ionisation ion source coupled to a HPLC system has been used to develop a method which can accurately measure morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in plasma, whole blood and post-mortem blood following solid-phase extraction. The method can also qualitatively detect various other opioids and related compounds including: codeine, dihydrocodeine (and metabolites), noscapine, papaverine and 6-acetylmorphine (6-AM). The method has been favourably compared to an existing laboratory method using a now discontinued radio-immunoassay technique. The advantage of measuring the glucuronides directly rather than following deconjugation by β-glucuronidase has also been shown. Detection and quantification of compounds was achieved using multiple reaction monitoring (MRM) incorporating the use of deuterated morphine and M3G as internal standards. Precision and accuracy was determined to be less than 10% at both high and low levels for all analytes and the calibration curve was deemed linear over an acceptable range. Recovery in blood was greater than 90% and ion suppression/enhancement was shown to be less than 15%. This method was applied to over 130 post-mortem cases involving the use of heroin, prescribed morphine and codeine. The range of concentrations of morphine, M3G and M6G was large (particularly in heroin and prescribed morphine cases), reflecting the many different factors involved with therapeutic use or fatal opiate poisonings, including tolerance associated with regular use, variable dose regimens and co-administration of other drugs. Detection of other constituents of the opium poppy such as noscapine and papaverine and metabolites of diacetylmorphine in the blood (6-AM) was useful in determining the source of the morphine (i.e. illicit heroin) and the rapidity of death after administration.

Development of a methodology to predict sticky deposits due to the destabilisation of dissolved and colloidal material in papermaking—application to different systems

Due to trends in papermaking like closed water systems or higher use of recovered paper (RP) as a raw material, a large number of contaminants are accumulated in the system as dissolved and colloidal material (DCM). When the DCM is destabilised by a sudden change in the system conditions, it produces sticky deposits, called secondary stickies that affect the papermaking processes and the quality of the final product. The existing laboratory methods to predict DCM destabilisation have limitations such as low reproducibility or they do not distinguish between sticky and non-sticky materials or high volumes are necessary to perform the test. In order to solve these problems, a methodology to predict the depositability potential of DCM has been developed by the Complutense University of Madrid. The methodology incorporates the destabilisation of the DCM by polymer addition, DCM deposition on collector surfaces and the quantification of the formed deposits by image analysis. Results show that the methodology has good reproducibility with a margin of error less than 10%. The methodology was applied to study: the potential of different formulations of adhesives to form stickies; the formation of deposits with different contaminant types and several concentrations; the efficiency of deposit control agents and the behaviours of different recovered paper grades.

Urine drugs of abuse testing at the point-of-care: clinical interpretation and programmatic considerations with specific reference to the Syva Rapid Test (SRT)

We evaluated a new point-of-care (POC) device for urine drugs of abuse (DOA) screening including appropriate clinical interpretation and potential benefits in a large academic medical center. Two hundred consecutive urine samples were tested using Syva Rapid Test (SRT) and existing laboratory methods (Syva EMIT II). Agreement between methods was acceptable with some considerations. Threshold concentration differences, drug interferences, and cross-reactivity profiles of the class-specific assays resulted in performance differences between the POC and central laboratory methods. Clinical interpretation of POC results requires an understanding of these issues as well as the limitations of urine testing. While urine-based screening is used in workplace testing and in a variety of clinical applications, quantitative blood measurements of some drugs (e.g. ethanol, acetaminophen, salicylate, ±tricyclic antidepressants) will remain important in the emergent setting. Performance of the SRT method takes approximately 10 min. Consequently, the major advantage over laboratory methods is rapid turnaround time. At the Massachusetts General Hospital, the most important application is for samples from the emergency department (about 1700/year). Each institution should assess its own needs and capabilities with regard to POC versus laboratory-based testing for DOA.

The Role of Gypsum in Production of Sulfate-Induced Deformation of Lime-Stabilized Soils

Gypsum is a major source of sulfate that produces sulfate-induced heave in lime-treated soils beneath roads and other paved structures. This deformation of pavement subgrade is known to result from the growth of the basic hydrous calcium aluminum sulfate mineral, ettringite, or a silica-bearing analog, thaumasite. The problem occurs in soils that have been treated with lime (CaO) for subgrade stabilization. Gypsum is a common sulfate mineral in sedimentary rocks and soils, and in north Texas it is present in soils developed on the montmorillonitic Eagle Ford Group shales (Upper Cretaceous). Because these soils are highly unstable the conventional treatment for road subgrade includes the addition of lime (CaO) or some other cementitious material such as fly ash or Portland cement. The pyrite-bearing Eagle Ford shale contains gypsum (CaSO4 • 2H2O) produced by reaction of calcium carbonate in the shale with acid sulfate from oxidation weathering of pyrite (FeS2). Sulfate movement upward in the soils can occur by capillarity, and it can be carried downward by infiltration, an often incomplete or interrupted event that leaves gypsum stranded as a soil evaporite. Once formed, the moderately soluble gypsum is retained in the clay-rich soils because of their low hydraulic conductivities, which makes them, in essence, reservoirs of gypsum. Experiments performed for this study confirm that gypsum in a lime-treated subgrade soil can supply sulfate for the growth of the expansive mineral ettringite. No sulfate external to the subgrade of the road is necessary for the reaction to occur. Gypsum is widely distributed in soils and surface outcrops in the western U.S. and should be the first mineral suspected where sulfate-induced heave has been diagnosed. Although gypsum is a moderately soluble mineral, it may be abundant in soils in regions with humid climates if its sulfate is derived from pyritic black shales by oxidation during soil formation. Eagle Ford soils do not produce sulfate-induced heave everywhere that road base has been lime-treated, but the problem is observed most frequently where roads follow streams, or run across low-lying areas or hillside slopes. Other studies have documented a correlation between deformation and major precipitation events. Ground water, soil water, and surface drainage regimes appear to control the specific sites at which severe deformation may take place within the stratigraphically-controlled belts of gypsum-bearing soils. Soluble sulfate tests currently in use to identify soils with the potential for sulfate-induced heave are known for inconsistent results. Total sulfate in a soil is a better predictor of the problem, and when gypsum is the sulfate mineral it can be determined quantitatively by existing laboratory methods. Stratigraphy is a first-order guide to where sulfate-induced heave may occur in the north Texas region, thus geologic maps of the Eagle Ford shale outcrop belt are also indicators of areas of possible sulfate-induced deformation.

A Flow Cytometric Assay of Platelet Activation Marker P-Selectin (CD62P) Distinguishes Heparin-induced Thrombocytopenia (HIT) from HIT with Thrombosis (HITT)

Heparin induced thrombocytopenia (HIT) is a well-known complication of heparin administration but usually resolves upon discontinuation without sequelae. However, a small proportion of HIT patients develop thrombosis associated with HIT, designated as HITT, which is often life-threatening and may lead to gangrene and amputations. Existing laboratory methods of confirming HIT/HITT do not distinguish between HIT and HITT. We report a flow cytometric assay of platelet activation marker CD62P to distinguish the effects of addition of HIT vs. HITT plasma to normal blood. Briefly, normal whole blood was incubated with platelet-poor plasma from 12 patients with HITT, 30 with HIT, and 65 controls, in presence and absence of heparin, and expression of CD62P was assayed by flow cytometry. When the ratios of fluorescent intensity of CD62P with heparin divided by that without heparin were compared, HITT plasma induced significantly higher ratios than HIT plasma (HITT ratios approximately 2.5 vs. HIT ratios approximately 1.2; p <0.001). Eleven of 12 HITT patients were positive by this test but only 5 of 30 HIT patients were positive (p <0.0005). In a case of HIT with silent thrombosis, this assay gave a positive results prior to clinically evident thrombosis. In conclusion, this method distinguishes HITT from HIT and may be clinically useful in the detection of HITT, allowing early intervention for preventing catastrophic thrombosis.

Structure and magnetic properties of sintered iron-chromium with added P : T.Kato et al. (Daido Inst. of Technology, Nagoya, Japan.) J. Jpn. Soc. PowderPowder Metall., vol 44, no 2, 1997, 179–184. (In Japanese.)

The problem of determining the elastic moduli of some particulate materials (granular, non-cohesive) is analysed. First, a brief survey of existing laboratory methods and a literature review are presented. Some basic shortcomings regarding the interpretation of commonly accepted tests and the determination of material parameters are discussed. Then an original method of determining the elastic moduli of particulate materials is proposed. The method is based on a new interpretation of oedometric tests, with additional measurement of lateral stresses. An original feature of this interpretation is that the first phase of unloading is elastic. The elastic moduli for various particulate materials, such as soils, grains, powders and metal balls, are determined. It has been shown that the elastic moduli of particulate materials do not significantly depend on either the initial density of the material or the stress level, in contrast to some widely accepted opinions.

Elastic moduli of non-cohesive particulate materials

The problem of determining the elastic moduli of some particulate materials (granular, non-cohesive) is analysed. First, a brief survey of existing laboratory methods and a literature review are presented. Some basic shortcomings regarding the interpretation of commonly accepted tests and the determination of material parameters are discussed. Then an original method of determining the elastic moduli of particulate materials is proposed. The method is based on a new interpretation of oedometric tests, with additional measurement of lateral stresses. An original feature of this interpretation is that the first phase of unloading is elastic. The elastic moduli for various particulate materials, such as soils, grains, powders and metal balls, are determined. It has been shown that the elastic moduli of particulate materials do not significantly depend on either the initial density of the material or the stress level, in contrast to some widely accepted opinions.

Molecular determination of dermatophyte fungi using the arbitrarily primed polymerase chain reaction.

Dermatophytes are keratinophilic fungi capable of causing dermatophytosis (commonly known as tinea or ringworm) in humans and animals. Previously, we reported the differentiation of the common dermatophytes Trichophyton rubrum, T. mentagrophytes and T. tonsurans using a random primer 5'-ACCCGACCTG-3' (OPAA11) in the arbitrarily primed polymerase chain reaction (AP-PCR). In the present study, by examining additional dermatophytes including eight Microsporum spp., 16 Trichophyton species/subspecies and Epidermophyton floccosum using both OPAA11 and a second random decamer 5'-GAGAGCCAAC-3' (OPD18) in AP-PCR, we show that except for T. rubrum and T. gourvilli, and three T. mentagrophytes varieties, most of the dermatophyte fungi investigated formed distinct DNA band patterns on gel electrophoresis. The amplification of specific DNA bands in AP-PCR appeared to be independent of culture variations shown by dermatophyte isolates. These results provide the basis for the rapid identification of dermatophytes at the genetic level, supplementing existing laboratory methods and improving the diagnosis of human dermatophytosis.