Use Of Laboratory Analysis Research Articles

The origins of transparent and non-transparent white pumice: A case study of the 52 ka Maninjau caldera-forming eruption, Indonesia

The VEI 7 (220–250 km3), a 52 ka eruption of the Maninjau caldera in Indonesia produced two distinct types of white pumices: transparent (TWP) and non-transparent (NTWP). These pumices were identified on outcrops, based on their qualitative traits, without the use of laboratory analyses (geochemical and textural). TWPs are typically fragile, irregular in shape, and have a transparent glass of vesicle walls around visible large vesicles, whereas NTWPs are relatively strong, blocky in shape, and have a non-transparent glass due to invisible small vesicles. Based on chemical and petrographical analyses, both pumice types were crystal-poor (avg. of 3.3%), with similar mineralogy, glass compositions (avg. 78.5 wt% SiO2), and plagioclase core compositions (avg. of An28). From component analysis, we found that the abundance of TWP decreased towards the upper stratigraphic ignimbrite deposits, along with an increase in NTWP, grey pumice, banded pumice, and lithic (non-juvenile) contents. We defined two vesicle populations with a threshold diameter of 0.1 mm based on bimodal vesicle size distributions by textural analysis for TWP and NTWP. Large vesicles correspond to preexisting bubbles that form in the magma chamber (pheno-vesicle, > 0.1 mm), whereas small vesicles in the groundmass (matrix-vesicle, < 0.1 mm) are attributed to second nucleation in the conduit during the eruption. We performed a comparison using vesicle data (pheno- and matrix-vesicles) for these two white pumice types. Pheno- and matrix-vesicularity showed a negative correlation. Thus, the boundary between TWP and NTWP was also quantitatively confirmed by the volume fraction ratio of the pheno- and matrix-vesicles. This evidence suggests that TWP originated from pheno-bubble-dominated magma (at least 0.1% volume fraction of pheno-bubbles in the magma chambers), whereas NTWP originated from pheno-bubble-poor magma. The variation in the abundance of TWP and NTWP in the stratigraphic positions implies the rough stratification of pre-existing bubbles (pheno-bubbles) in the pre-eruptive magma chamber, where the overpressure developed to trigger and drive the eruption. The two regimes control the formation of matrix-vesicles: (1) a pheno-bubble-controlled regime, and (2) a decompression-controlled regime. Based on a correlation between pheno-vesicle number density (PVND) and matrix-vesicle number density (MVND) together with numerical calculations based on a previous study, we suggest that the TWPs with the highest pheno-vesicularity formed under conditions corresponding to the first regimes, while the NTWPs formed in the second regime, where MVND is mostly determined by decompression rate. We also argue that NTWP is the only representative juvenile for estimating magma decompression rate, as the MVND value in TWP do not represent the actual second nucleation processes. Therefore, the occurrence of NTWP in the entire deposits with a relatively similar MVNDs value might suggest that the early and final eruption stages experienced a relatively similar magma decompression rate.

High-Resolution Pore-Scale Water Content Measurement in a Translucent Soil Profile from Light Transmission

HighlightsResearch methods are needed to study preferential flow processes at pore scale and high temporal resolution.Novel verification of the light transmission method shows high efficiency to measure rapid transient soil water flow.Recast of a previous physical model allows reliable pore-scale water content quantification in translucent soil profiles.Insights from the light transmission method can inform preferential flow modeling efforts.Abstract. Understanding rapid transient flows in the soil unsaturated zone continues to be a major challenge in hydrology and water quality engineering. For example, surface runoff mitigation by riparian buffers can be limited by rapid transient flows due to the natural propensity of these areas for preferential flow pathways (i.e., caused by roots, wormholes, or wetting/drying cycles). However, current monitoring technologies are limited in their ability to capture rapid soil preferential flows at high spatial and temporal resolutions. Among the state-of-the-art technologies to monitor preferential flow, the light transmission method (LTM) has become a promising tool to quantify pore-scale water contents at a laboratory scale, but its reliability and consistency need further study. The objectives of this study are to recast a previously developed LTM physical model, propose a novel verification method to assess LTM reliability to measure pore-scale water dynamics in laboratory translucent soil profiles, and identify the representative pore radius of translucent soil profiles based on their average number of pores. This study found a high measuring efficiency with LTM for soil moisture and drainage estimations (NSE &amp;gt; 0.98, RMSE &amp;lt; 5.4%), showing its potential for use in laboratory analysis of pore-scale rapid transient water dynamics typically found in preferential flow through the vadose zone. This study also shows that the parameter traditionally associated with the number of pores in a translucent soil profile is a fitting parameter with no direct physical meaning. Keywords: Beer-Lambert law, Fresnel law, Light transmission method, Preferential flow, Riparian buffer, Vadose zone.

Profile of Steroid Hormones and sex Hormone-Binding Globulin of Elite Soldiers

Background: Military police training should characterize the necessary abilities to conduct their activities with excellence. Biochemical parameters have a significant role in the performance of individuals and, therefore, are of crucial importance when trying to improve the teamwork of police officers, particularly for special operations groups. Hence, the use of laboratory analysis in activities that cause great physiological stress is of paramount importance. Objectives: The present study aimed to evaluate the profile of steroid hormones and the sex hormone-binding-globulin of soldiers belonging to a special operations force. Methods: In this cross-sectional study, blood samples of 75 volunteers collected after 12 hours of fasting are analyzed. Data were analyzed using descriptive statistics (i.e., mean and standard deviation) and compared to the reference values for each biomarker, referencing each individual in their age group. Results: Most of the participants presented adequate concentrations for their respective ages in relation to the data analyzed. Even the inclusion of individuals from different age groups did not change the good results found in the group. Conclusions: The positive results found in such a heterogeneous group with respect to age group can be attributed to an extremely rigorous selection process and a training program that elevates them to the rank of elite soldiers of the military police.

POTTERY SAMPLES RECOVERED FROM ABU ERTEILA (SUDAN) – CORRELATION OF MACROSCOPICALLY IDENTIFIED FABRICS WITH LABORATORY-DEFINED RAW MATERIAL GROUPS

This article reports on the use of laboratory analysis to examine whether pottery recovered from excavations at Abu Erteila includes wares made at the same workshops as pottery found at other Meroitic sites in the region. It also examines whether wares deemed typical of the Abu Erteila ceramic assemblage were made of the same raw materials as pottery at neighbouring sites or clay used at other workshops. Particular attention was paid to assessing whether samples with fabrics which macroscopically resemble the Musawwarat fabrics were indeed made at workshops in Musaw­­warat or whether this macroscopic similarity is deceptive.&#x0D;

Quantification of tryptophan in plasma by high performance liquid chromatography

A simple, rapid and selective method using high-performance liquid chromatography with ultraviolet detection (267 nm) was applied for the determination of tryptophan in plasma. Separation was carried out on a C18 column (150 x 4.6 mm internal diameter) in 6 min. The mobile phase consisted of 5 mM the sodium acetate and acetonitrile (92:8, v/v). The method was shown to be precise and accurate, and good recovery of analyte was achieved, characterizing the method as efficient and reliable for use in laboratory analysis.

Executive Summary: Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

Multiple laboratory tests are used in the diagnosis and management of patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially. An expert committee compiled evidence-based recommendations for the use of laboratory analysis in patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. A draft of the guidelines was posted on the Internet, and the document was modified in response to comments. The guidelines were reviewed by the joint Evidence-Based Laboratory Medicine Committee of the AACC and the National Academy of Clinical Biochemistry and were accepted after revisions by the Professional Practice Committee and subsequent approval by the Executive Committee of the American Diabetes Association. In addition to the long-standing criteria based on measurement of venous plasma glucose, diabetes can be diagnosed by demonstrating increased hemoglobin A(1c) (Hb A(1c)) concentrations in the blood. Monitoring of glycemic control is performed by the patients measuring their own plasma or blood glucose with meters and by laboratory analysis of Hb A(1c). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed. The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Position Statement Executive Summary: Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUNDMultiple laboratory tests are used in the diagnosis and management of patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.APPROACHAn expert committee compiled evidence-based recommendations for the use of laboratory analysis in patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. A draft of the guidelines was posted on the Internet, and the document was modified in response to comments. The guidelines were reviewed by the joint Evidence-Based Laboratory Medicine Committee of the AACC and the National Academy of Clinical Biochemistry and were accepted after revisions by the Professional Practice Committee and subsequent approval by the Executive Committee of the American Diabetes Association.CONTENTIn addition to the long-standing criteria based on measurement of venous plasma glucose, diabetes can be diagnosed by demonstrating increased hemoglobin A1c (HbA1c) concentrations in the blood. Monitoring of glycemic control is performed by the patients measuring their own plasma or blood glucose with meters and by laboratory analysis of HbA1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed.SUMMARYThe guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Decision-making in general practice: the effect of financial incentives on the use of laboratory analyses

This paper examines the reaction of general practitioners (GPs) to a reform in 2004 in the remuneration system for using laboratory services in general practice. The purpose of this paper is to study whether income motivation exists regarding the use of laboratory services in general practice, and if so, the degree of income motivation among general practitioners (GPs) in Norway. We argue that the degree of income motivation is stronger when the physicians are uncertain about the utility of the laboratory service in question. We have panel data from actual physician-patient encounters in general practices in the years 2001-2004 and use discrete choice analysis and random effects models. Estimation results show that an increase in the fees will lead to a small but significant increase in use. The reform led to minor changes in the use of laboratory analyses in GPs' offices, and we argue that financial incentives were diluted because they were in conflict with medical recommendations and existing medical practice. The patient's age has the most influence and the results support the hypothesis that the impact of income increases with increasing uncertainty about diagnosis and treatment. The policy implication of our results is that financial incentives alone are not an effective tool for influencing the use of laboratory services in GPs' offices.

Waldenstrom's Microglobulinemia Presenting with Recurrent Angioedema Secondary to C1q Esterase Inhibitor (C1 INH) Deficiency

AbstractAbstract 5009 Description:A 57 year-old Bangladeshi man presented to the emergency room with a 4-day history of shortness of breath, productive cough and sensation of choking. He had a history of recurrent dyspnea, chest pain and chronic bilateral pedal edema. He had recent admissions for similar complaints at different hospitals where he was diagnosed with low grade non-Hodgkin lymphoma not requiring treatment and was discharged with bronchodilators and anti-tussives. He was symptom-free between episodes. There was no fever, night sweats or weight loss and there was no history of asthma. Physical exam revealed moderate dyspnea with some stridor, cervical lymphadenopathy with many firm and mobile small lymph nodes. There was no hepato-splenomegaly, urticaria or rashes. Results of routine blood tests including CBC and C-reactive protein were normal. Chest X-ray showed mild pulmonary congestion and CT images of the chest and abdomen showed multiple lymph nodes of about 1–1.5 cm in size. X-rays of the hands showed multiple small lytic lesions. Laryngoscopy showed laryngeal edema. Bone marrow biopsy showed a few paratrabecular areas with increased numbers of small lymphocytes and a lymph node biopsy revealed low grade B-cell lymphoma with plasmacytic differentiation, which was positive for CD19, 20, 22, 38, and CD44. Serum viscosity was 1.6. Immunological studies showed a low C4 at 4 mg/dl (normal range 10–40 mg/dl), low C1q at <3.6 (normal range 5–8.6), C1 esterase inhibitor low-normal at 16 (normal range 11–26). Serum immunoglobulins showed IgM gammopathy with low IgA and normal IgG levels. Beta-2 microglubulin was also elevated at 4.93 mg/dl (normal range < 2.51). Serum protein electrophoresis showed a monoclonal IgM spike measuring 1.5 g/dl with immunofixation positive for a IgM kappa band. Total protein, alpha2- and beta-globulins were elevated and urine electrophoresis was positive for kappa light chains. A diagnosis of Waldenström's macroglobulinemia with angioneurotic edema was made. He was treated with 4 cycles of bortezomib (Velcade®), dexamethasone and rituximab. The patient's angioedema and respiratory symptoms improved dramatically. Follow-up serum electrophoresis showed a very good response to treatment, with a major decrease in total protein and the M-spike. Complement levels returned to normal. Discussion:C1 is the first protein of the classical and kinin pathways which is an arm of the innate immune system. Triggering factors activate the complement cascade and lead to activation of C1 which in turn cleaves C2, the product of which is an inflammatory mediator responsible for angioedema by causing increased capillary permeability and extravasations. In C1INH deficiency, this process occurs uninhibited, triggered by minimal stimulation. C1q esterase inhibitor deficiency is a rare manifestation of Waldenström's macroglobulinemia with very few reported cases in literature. Symptoms are non-allergic, non-pruritic and clinical presentation depends on parts of the anatomy affected and may be as mild as inconvenient skin blotching up to life-threatening laryngeal edema or shock. They vary widely, often self limiting and recurrent. Angioedema, acquired or inherited, is complement mediated, characterized by low levels of complement proteins during attacks. C1INH deficiency can be acquired due to increased consumption or/and inactivation by circulating autoantibodies or secondary to lymphoproliferative diseases that lead to increased catabolism. These are often associated with B-cell disorders but may be associated with other disease patterns. Symptomatology is variable and periods of remission and recurrence lead to easy misdiagnosis and incomplete treatment. Proper diagnosis is dependent on awareness and knowledge of the various clinical presentations, adequate and focused use of laboratory analyses and immunopathology studies. The key to treatment is first therapy of the acute stage (in our patient with the use of intravenous steroids) and then more specific treatment of the underlying disease entity (in our patient with bortezomib, dexamethasone and rituximab). Conclusion:Waldenstrom's macroglobulinemia presenting with angioedema is rare, often misdiagnosed and acquired C1 esterase inhibitor deficiency should be at least ruled out, as presentation is varied and could be potentially life-threatening. Disclosures:No relevant conflicts of interest to declare.

Specific Primers for Rapid Detection ofMicrosporum audouiniiby PCR in Clinical Samples

This report describes application of PCR fingerprinting to identify common species of dermatophytes using the microsatellite primers M13, (GACA)4, and (GTG)5. The initial PCR analysis rendered a specific DNA fragment for Microsporum audouinii, which was cloned and sequenced. Based on the sequencing data of this fragment, forward (MA_1F) and reverse (MA_1R) primers were designed and verified by PCR to establish their reliability in the diagnosis of M. audouinii. These primers produced a singular PCR band of 431 bp specific only to strains and isolates of M. audouinii, based on a global test of 182 strains/isolates belonging to 11 species of dermatophytes. These findings indicate these primers are reliable for diagnostic purposes, and we recommend their use in laboratory analysis.

Laboratory analyses for poisoned patients.

Guidelines on the appropriate availability and use of laboratory analysis have been produced by the National Poisons Information Service and the Association of Clinical Biochemists and are published in this issue. These are intended to support the consistent and high quality investigation of the poisoned patient.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

Multiple laboratory tests are used in the diagnosis and management of patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially. An expert committee drafted evidence-based recommendations for the use of laboratory analysis in patients with diabetes. An external panel of experts reviewed a draft of the guidelines, which were modified in response to the reviewers' suggestions. A revised draft was posted on the Internet and was presented at the AACC Annual Meeting in July, 2000. The recommendations were modified again in response to oral and written comments. The guidelines were reviewed by the Professional Practice Committee of the American Diabetes Association. Measurement of plasma glucose remains the sole diagnostic criterion for diabetes. Monitoring of glycemic control is performed by the patients, who measure their own plasma or blood glucose with meters, and by laboratory analysis of glycated hemoglobin. The potential roles of noninvasive glucose monitoring, genetic testing, autoantibodies, microalbumin, proinsulin, C-peptide, and other analytes are addressed. The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are of minimal clinical value at the present time, and measurement of them is not recommended.

Clinical Applications of Molecular Biology in Diagnostic Hematopathology

The structure and function of the immunoglobulin and Tcell receptor genes are reviewed and discussed in relation to clonality in hematologic malignancies and the use of laboratory analysis of DNA gene structure studies of Band T-cell malignancies. The applications of molecular diagnostic techniques in hematologic disease, including lymphomas and leukemias, are reviewed. The use of restriction fragment length polymorphism (RFLP) analysis for bone marrow transplant patients and oncogene analysis in the diagnosis of hematologic malignancies is discussed. Polymerase chain reaction (PCR) techniques used to evaluate the BCR/abl gene fusion product in chronic myelogenous leukemia (CML) are briefly covered.

Correlation of Laboratory Analyses of Soil Properties and Infiltrometer Seepage from Drainwater Evaporation Ponds

ABSTRACT CONSTRUCTION of drainwater evaporation ponds for disposal of subsurface drainage effluent has raised concern over the extent to which seepage from these ponds affect shallow groundwater. Estimates of seepage rates based on laboratory measurements of soil properties are considered through comparison of results of laboratory and field measurements at 90 sites within a pond. Lognormal means of field measured seepage rates were over six times larger than associated means of hydraulic conductivities measured in the laboratory. The discrepancy can be attributed to potential compaction of extracted cores used in the laboratory, layering of pond soils contained within infiltrometers, and hydraulic gradients greater than unity in pond soils. Of the laboratory measurements considered, field seepage rates were most closely correlated with permeameter-based measurements of hydraulic conductivity and the clay content of the soil. Due to the number of factors involved in correlating results of laboratory and field experiments with respect to soil heterogeneities and sample consolidation, additional work in this area is necessary to validate use of laboratory analyses for estimates of seepage in the field.

Case clustering in cancer.

There is little evidence that time-space clustering is important in the epidemiology of leukemia, lymphoma, Burkitt's tumor, and myeloma. Clustering by interpersonal contact, particularly in Hodgkin's disease, does appear to occur, but more study is needed to warrant the conclusion that such contact is necessary for subsequent illness to develop. Future epidemiologic studies should include the use of laboratory analysis to evaluate the role of viruses, genetics, and environmental factors in cluster studies.