Changes in the Compressive Strength of Concrete in Thin Horizontally Formed Slabs

During compaction of a concrete mix, when thin slabs are formed in a horizontal position, the components of this mix become segregated. Heavy components fall to the bottom, and light components (air and water) move to the top. This process may suggest that the upper layers of concrete elements formed in a horizontal position may have lower compressive strength than the remaining part of the element. This problem is recognized and documented in many publications, but there was a publication whose test results indicate a lack of variability in the compressive strength of concrete across the thickness of tested elements. The discrepancies appearing in the evaluation of concrete homogeneity was the reason for conducting destructive tests of the compressive strength of concrete across the thickness of horizontally concreted test elements that imitate thin slabs. The obtained results of the destructive compressive strength confirmed previous results regarding the heterogeneity of concrete. They clearly indicate that there is a differentiation of the compressive strength of concrete across the thickness of a thin element, which remained in a liquefied state for a certain time during its formation. The longer the duration of this state across the entire thickness of the formed element, the greater the differentiation of the compressive strength between the top and bottom layers.

Establishment of the intelligent verification criteria for a routine urinalysis analyzer in a multi-center study

Background Although laboratory information system (LIS) is widely used nowadays, the results of routine urinalysis still need 100% manual verification. We established intelligent verification criteria to perform the automated verification process and reduce manual labor. Methods A total of 4610 urine specimens were obtained from the patients of three hospitals in Beijing, China. Firstly, 895 specimens were measured to establish the reference intervals of formed-element parameters in UF5000. Secondly, 2803 specimens were analyzed for setting up the intelligent verification criteria (including the microscopic review rules and manual verification rules). Lastly, 912 specimens were used to verify the efficacy and accuracy of the intelligent verification criteria. Phase-contrast microscopes were used for the microscopic review. Results Employing a results level corresponding relationship in specific parameters including hemoglobin (red blood cell [RBC]), leukocyte esterase (white blood cell [WBC]) and protein (cast) between the dry-chemistry analysis and formed-element analysis, as well as instrument flags, we established seven WBC verification rules, eight RBC verification rules and four cast verification rules. Based on the microscopy results, through analyzing the pre-set rules mentioned earlier, we finally determined seven microscopic review rules, nine manual verification rules and three auto-verification rules. The microscopic review rate was 21.98% (616/2803), the false-negative rate was 4.32% (121/2803), the total manual verification rate was 35.71% (1001/2803) and the auto-verification rate was 64.29% (1802/2803). The validation results were consistent. Conclusions The intelligent verification criteria for urinary dry-chemistry and urinary formed-element analysis can improve the efficiency of the results verification process and ensure the reliability of the test results.

Pathogenic peculiarities of disseminated intravascular coagulation of various ethiology

ДВС-синдром - тяжелое осложнение, часто приводящее к полиорганной недостаточности и нередко к летальному исходу. Как и любой синдром, он полиэтиологичен, что закономерно приводит к различным механизмам его формирования. Основные проявления синдрома диссеминированного внутрисосудистого свертывания крови - тромбообразование и кровоточивость. Следствием массивного тромбообразования в микроциркуляторном русле внутренних органов является развитие дистрофических изменений и органной недостаточности. Кровотечения, в свою очередь, приводят к уменьшению объема циркулирующей крови, артериальной гипотензии и гемической гипоксии, а в наиболее тяжелых случаях - и к летальному исходу. Однако механизмы развития и степень выраженности вышеуказанных нарушений далеко не всегда одинаковы. Поскольку данный синдром может быть обусловлен большим количеством причин (в настоящее время описано более 150 заболеваний, при которых может развиваться синдром), то наибольшим разнообразием отличаются именно инициальные его звенья. Основными пусковыми механизмами ДВС-синдрома могут быть: активация форменных элементов крови и усиление процесса их микровезикуляции, активация коагуляционного гемостаза по внешнему и внутреннему путям, недостаточность антикоагулянтов и избыточная активность фибринолитической системы. Разные этиологические факторы (сепсис, акушерская патология, лейкозы и другие злокачественные опухоли, травмы и т.д) неодинаково влияют на функцию компонентов системы гемостаза. В зависимости от степени выраженности нарушений вышеуказанных механизмов может развиться ДВС-синдром с преобладанием коагуляции или с преобладанием фибринолиза либо с их сбалансированной активацией. Клинические проявления этих форм ДВС-синдрома, а также продолжительность и выраженность стадий (гиперкоагуляция, коагулопатия потребления с компенсаторной активацией фибринолиза, дефибринация крови и гиперактивация фибринолиза) также будут отличаться. Следовательно, знание преобладающего нарушения в системе гемостаза при наличии заболевания, потенциально опасного в плане развития ДВС-синдрома, позволит подобрать наиболее оптимальные способы его профилактики, диагностики и лечения. DIC is a severe complication, often resulting in multi-organ failure and fatal outcome. As any syndrome, it is polyethiologic, while a big number of its causes logically leads to various mechanisms of its forming. Main manifestations of the disseminated intravascular blood coagulation syndrome are clottage and haemorrhage. A result of a massive clottage in microcirculatory bed of internal organs is development of dystrophic changes in them and organ failure. Haemorrhage in its turn, results in decreased volume of circulating blood, arterial hypotension and hemic hypoxia, in most severe cases leading to the fatal outcome. Although, development mechanisms and manifestation degree of the disorder mentioned above are not always the same. As the syndrome may result from a great number of causes (currently, over 150 diseases have been described with which it can develop), namely its initial stages are different to the greatest extent. Main triggering mechanisms of the DIC may be: blood formed element activation and increased process of their microvesiculation, activation of coagulative hemostasis in intrinsic and extrinsic pathways, lack of anticoagulants and excessive activity of fibrinolytic system. Various ethiologic factors (sepsis, obstetrical pathology, leucosis and other malignant tumours, traumas, etc) have different effect on function of hemostasis system components. Depending on the degree of the above mentioned disorders mechanisms manifestation, the DIC may develop with prevailing coagulation, with prevailing fibrinolysis or with their balanced activation. Clinical manifestations of these DIC forms, as well as duration and manifestation degree of its stages (hypercoagulation, coagulopathy of consumption with compensatory activation of fibrinolysis, defibrination of the blood and excessive activation of fibrinolysis) will be different as well. Consequently, knowing the prevailing disorder in hemostasis system during a disease that is potentially dangerous in terms of the DIC development offers to find optimal methods of its prevention, diagnosing and treatment.

Nonspecific esterases of the formed elements: zymograms produced by pH 9.5 polyarcrylamide gel electrophoresis

The formed elements of human blood each contain multiple isoenzymes of nonspecific esterase that hydrolyze short chain alpha naphthyl esters. Zymograms that are characteristic of each type of formed element are obtained by subjecting purified preparations of each to polyacrylamide slab gel electrophoresis at pH 9.5 and subsequent staining of the gels for esterase activity. The most prominent isoenzyme detected is a species of low mobility that is reactive with either acetyl or butyryl esters and is highly sensitive to inhibition by 40 mM sodium fluoride. Also detected are several major acetyl esterases and a single butyryl esterase, all of which are relatively fluoride resistant. The intercellular distribution of isoenzymes varies from element-specific to pancellular. The prominent fluoride-sensitive acetyl, butyryl esterase, is the major isoenzyme of monocyte zymograms, which is consistent with the well known cytochemistry of monocytes. Lesser but significant amount (2%-3% of monocyte levels) of this isoenzyme were also detected in granulocyte zymograms. This system may prove useful in the study of differentiation of blood cells and in the classification of acute leukemias.

Nonspecific esterases of the formed elements: zymograms produced by pH 9.5 polyarcrylamide gel electrophoresis

The formed elements of human blood each contain multiple isoenzymes of nonspecific esterase that hydrolyze short chain alpha naphthyl esters. Zymograms that are characteristic of each type of formed element are obtained by subjecting purified preparations of each to polyacrylamide slab gel electrophoresis at pH 9.5 and subsequent staining of the gels for esterase activity. The most prominent isoenzyme detected is a species of low mobility that is reactive with either acetyl or butyryl esters and is highly sensitive to inhibition by 40 mM sodium fluoride. Also detected are several major acetyl esterases and a single butyryl esterase, all of which are relatively fluoride resistant. The intercellular distribution of isoenzymes varies from element-specific to pancellular. The prominent fluoride-sensitive acetyl, butyryl esterase, is the major isoenzyme of monocyte zymograms, which is consistent with the well known cytochemistry of monocytes. Lesser but significant amount (2%-3% of monocyte levels) of this isoenzyme were also detected in granulocyte zymograms. This system may prove useful in the study of differentiation of blood cells and in the classification of acute leukemias.

THE BLOOD IN HOG CHOLERA

1. Prolonged and systematic examination of blood from swine with hog cholera has failed to reveal any formed element that could be identified with the etiological virus. Culture has likewise been unsuccessful. 2. The quantitative blood changes in hog cholera consist in a slowly progressive anemia, usually moderate in degree, and a rapidly progressive severe leucopenia affecting cells of the polymorphonuclear series most markedly but also including those of the lymphocytic series. 3. Incubation of hog cholera blood results in a further progress of the leucopenia, in vitro, if heparin has been used as the anticoagulant, but there is no significant change if potassium oxalate or sodium citrate has been used. 4. Consideration of the leucocytic reactions prevailing in experimental infection with B. suisepticus, in infectious enteritis, in swine influenza, following successful immunization against hog cholera, and following infection of cholera-sick swine with secondary invaders indicates that the leucocyte count would be of aid in the differential diagnosis of hog cholera.