A post-classical theory of enamel biomineralization… and why we need one / 国际口腔科学杂志·英文版

Enamel crystals are unique in shape, orientation and organization. They are hundreds of thousands times longer than they are wide, run parallel to each other, are oriented with respect to the ameloblast membrane at the mineralization front and are organized into rod or interrod enamel. The classical theory of amelogenesis postulates that extracellular matrix proteins shape crystallites by specifically inhibiting ion deposition on the crystal sides, orient them by binding multiple crystallites and establish higher levels of crystal organization. Elements of the classical theory are supported in principle by in vitro studies; however, the classical theory does not explain how enamel forms in vivo. In this review, we describe how amelogenesis is highly integrated with ameloblast cell activities and how the shape, orientation and organization of enamel mineral ribbons are established by a mineralization front apparatus along the secretory surface of the ameloblast cell membrane.

Accuracy of the ultrasonic cardiac output monitor in healthy term neonates during postnatal circulatory adaptation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Echocardiography is regarded as a gold standard for measuring hemodynamic values. The ultrasonic cardiac output monitor (USCOM) is a new method for measuring hemodynamics and could provide non-invasive point of care guidance. So far, there are no published USCOM reference values for neonates, nor has USCOM's accuracy been established in this population. We aimed to determine the accuracy and clinical utility of the USCOM in healthy neonates relative to published echocardiographic data, to establish normal hemodynamic parameters that it measures, and to assess the possible role of USCOM as an alternative to echocardiography as a trend monitor.</p><p><b>METHODS</b>Right and left heart hemodynamics of 90 normal neonates were measured during circulatory adaptation over the first three days of life using the USCOM and automated oscillotonometry.</p><p><b>RESULTS</b>Heart rate showed a significant decline from days one to three, from 126 to 120 (P < 0.001). Systolic, diastolic and mean arterial pressures all increased significantly from 66 to 71 mmHg, 33 to 38 mmHg and 44 to 49 mmHg, respectively (P < 0.001 in each case). Right ventricular cardiac index (RV-CI) showed no change with a mean of 5.07 L × min(-1) × m(-2). Left ventricular cardiac index (LV-CI) declined from 3.43 to 3.00 L × min(-1) × m(-2) (P < 0.001). RV-CI exceeded LV-CI on all three days by a mean of 61%. The systemic vascular resistance index (SVRI), based on LV-CI, increased significantly over the three days from 1083 to 1403 dyne × sec × cm(-5) × m(2) (P < 0.001).</p><p><b>CONCLUSIONS</b>Normal neonatal hemodynamic values, as indicated by USCOM, were established. LV-CI measurement showed excellent agreement with published echocardiographic studies. RV-CI was constant and exceeded LV-CI for all three days of this study. It may be falsely high due to flow velocity measurement errors arising from the pulmonary branch arteries, and may represent a limitation of the USCOM method. The progressive rise of arterial pressure and SVRI despite a declining LV-CI may indicate functional closure of the ductus arteriosus, with the greatest change occurring within the first 24 hours. Evidence of closure of the foramen ovale was not observed.</p>

phylogenetic placement of Picoa, with a first report on Picoa lefebvrei [Pat.] Maire [=phaeangium lefebvrei] from Iran

Desert truffles, hypogeous Pezizales [Ascomycota], are difficult to identify due to evolutionary convergence of morphological characters among taxa that share a similar habitat and mode of spore dispersal. In this paper we document the presence of Picoa lefebvrei [Pat.] Maire [=Phaeangium lefebvrei] in Iran and use phylogenetic analysis of the ITS and 28s rDNA to show that this species belongs to the Geopora-Tricharina clade of the Pyronemataceae [Pezizales, Ascomycota]. Picoa lefebvrei was originally placed in the genus Phaeangium because of notable spore ornamentation not present in other species of Picoa. However, our analyses of both phylogenetic and morphological data suggest that P. lefebvrei is closely related to Picoa juniperi Vittad, the type species for the genus Picoa

Feasibility of local cotton stalks for production of activated carbon by H3PO4 on a pilot scale

Good adsorbing carbon was obitained, for the first time in a pilot scale, from cotton stalks in a locally-designed rotary pyrolyzer. Activation was performed in absence of any purging gases by imprgnation with 50% H3P04 followed by heat treatment at 420°C. Mechanically cut short sticks were soaked in diluted H3PO4 for a short duration [Batch 1] and an extended period [Batch 2] prior to thermal treatment. The derived carbons contained both coarse and fine grains with acidic effect. Porosity was characterized by N2 adsorption at 77 [o]K and the isotherms analyzed by the alpha-method to estimate total and microporous surface areas in addition to total and microporous volumes. The produced carbons exhibited well-developed porosity that was essentially microporous in composition. Several key performance parameters were altered considerably as a result of impregnation with H3PO4 and the extended chemical activation period [Batch 2]. Most of the internal porosity of both carbons was accessible to adsorption of iodine, whereas the uptake of methylene blue dye was proportional to the average size of micropores which were larger for the batch with a longer acid soaking time. SEM and FTIR investigations revealed the presence of a developed honeycomb structure and different oxygen functionalities on surfaces of the activated products which are advantageous in liquid-phase applications. Preliminary laboratory-scale experiments with Pb[II] indicate that adsorption capacity of target heavy metals compares favorably with commercially-available activated carbons. The raw material, pre-processing, and activation process prove feasible for the production of activated carbon on a large scale, thereby providing a sustainable strategy for treatment of toxic waste streams

Comparison and Verification of BSE Surveillance in USA and Japan

Objective: The objectives of this study are to (1) compare the BSE surveillance systems of Japan and the United States (US), and to (2) validate the US enhanced BSE Surveillance program. Methods: This study compares the BSE surveillance systems in Japan and the US, specifically focusing on the procedures of initial test, diagnosis and confirmation. The study further examines the validity of statistical conclusions made in the US enhanced surveillance program based on the data collected from the BSE inspection performed by the Ministry of Health, Labor and Welfare of Japan (MHLW) and the Ministry of Agriculture, Forestry and Fisheries of Japan (MAFF) between October 18, 2001 and July 31, 2004. The inspection targeted all slaughtered healthy and high risk cattle. Results: The US enhanced surveillance program assumes no BSE occurrence in the normal adult cattle population and thus its inspection focuses only on high risk cattle. The BSE inspection performed in Japan, however, revealed that 0.00022% of the normal adult cattle were BSE-infected using the US criteria. Assuming that the same ratio of cattle was BSE-infected in the US, the Japan finding indicates that approximately 30% of the US slaughtered normal cattle population aged 30 months and over needs to be tested to satisfy the statistical condition used by the US (i.e., 99% confidence level). On the other hand, in order for Japan to perform the surveillance with a 99% confidence level (the statistical condition used by US), Japan needs inspect: (1) 60,539 high risk cattle (i.e., 60% of 100,583 high risk cattle); (2) 78% of normal adult cattle aged 30 months and over (1,088,589/1,387,522) and (3) 90% of normal cattle aged 30 months or less (1,845,138/2,050,154). Conclusion: The US enhanced surveillance program launched in July 2004 is based on the premise that no BSE occurs in normal adult cattle population. In Japan, however, BSE cases satisfying the US criteria have been found among the normal adult cattle. This fact suggests that the US needs to consider inspections targeting the normal adult cattle in the future. At the same time, for more efficient surveillance, Japan may need to consider BSE inspections targeting the high risk cattle population with a higher confidence level and normal adult cattle with a lower confidence level.

Comparison and verification of BSE surveillance in USA and Japan

<p><b>OBJECTIVE</b>The objectives of this study are to (1) compare the BSE surveillance systems of Japan and the United States (US), and to (2) validate the US enhanced BSE Surveillance program.</p><p><b>METHODS</b>This study compares the BSE surveillance systems in Japan and the US, specifically focusing on the procedures of initial test, diagnosis and confirmation. The study further examines the validity of statistical conclusions made in the US enhanced surveillance program based on the data collected from the BSE inspection performed by the Ministry of Health, Labor and Welfare of Japan (MHLW) and the Ministry of Agriculture, Forestry and Fisheries of Japan (MAFF) between October 18,2001 and July 31, 2004. The inspection targeted all slaughtered healthy and high risk cattle.</p><p><b>RESULTS</b>The US enhanced surveillance program assumes no BSE occurrence in the normal adult cattle population and thus its inspection focuses only on high risk cattle. The BSE inspection performed in Japan, however, revealed that 0.00022% of the normal adult cattle were BSE-infected using the US criteria. Assuming that the same ratio of cattle was BSE-infected in the US, the Japan finding indicates that approximately 30% of the US slaughtered normal cattle population aged 30 months and over needs to be tested to satisfy the statistical condition used by the US (i.e., 99% confidence level). On the other hand, in order for Japan to perform the surveillance with a 99% confidence level (the statistical condition used by US), Japan needs inspect: (1) 60,539 high risk cattle (i.e., 60% of 100,583 high risk cattle); (2) 78% of normal adult cattle aged 30 months and over (1,088,589/1,387,522) and (3) 90% of normal cattle aged 30 months or less (1,845,138/2,050,154).</p><p><b>CONCLUSION</b>The US enhanced surveillance program launched in July 2004 is based on the premise that no BSE occurs in normal adult cattle population. In Japan, however, BSE cases satisfying the US criteria have been found among the normal adult cattle. This fact suggests that the US needs to consider inspections targeting the normal adult cattle. This fact suggests that the US needs to consider inspections targeting the normal adult cattle in the future. At the same time, for more efficient surveillance, Japan may need to consider BSE inspections targeting the high risk cattle population with a higher confidence level and normal adult cattle with a lower confidence level.</p>