快速成型技术在颌骨缺损修复中应用的临床研究

目的：研究以CAD／CAM快速成型模型预成钛支架行颌骨缺损功能和外形重建的临床疗效。方法：选择四川大学华西口腔医院收治的5例颌骨良性肿瘤患者,术前螺旋CT及快速成型技术预成实体模型,并通过反求工程技术将健侧颌骨外形复制,制备钛修复体行患侧缺损修复,观察术后效果。结果：术后3个月、6个月复查患者对自身颌骨功能及外形较满意,均未出现因修复体导致的严重不良反应,张口度都接近恢复至正常,张口运动未出现明显异常,咬合关系良好。结论：运用快速成型技术设计并利用反求工程技术制造的个性化修复体进行颌骨缺损修复的方法能较好地恢复患者颌面部的功能和外形,副反应小,可以达到比较满意的修复效果。     

No social distancing between ORAI channels

ORAI1 is established as an essential component of Ca²⁺ release-activated Ca²⁺ (CRAC) channel which mediates store-operated Ca²⁺ entry (SOCE). However, the contributions of ORAI2 and ORAI3 to SOCE are not understood. We highlight a recent study which shows that ORAI proteins form heteromeric channels which tune SOCE over a range of stimulus intensities.     

Functional and evolutionary analysis of DXL1, a non-essential gene encoding a 1-deoxy-D-xylulose 5-phosphate synthase like protein in Arabidopsis thaliana

The synthesis of 1-deoxy-D-xylulose 5-phosphate (DXP), catalyzed by the enzyme DXP synthase (DXS), represents a key regulatory step of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for isoprenoid biosynthesis. In plants DXS is encoded by small multigene families that can be classified into, at least, three specialized subfamilies. Arabidopsis thaliana contains three genes encoding proteins with similarity to DXS, including the well-known DXS1/CLA1 gene, which clusters within subfamily I. The remaining proteins, initially named DXS2 and DXS3, have not yet been characterized. Here we report the expression and functional analysis of A. thaliana DXS2. Unexpectedly, the expression of DXS2 failed to rescue Escherichia coli and A. thaliana mutants defective in DXS activity. Coherently, we found that DXS activity was negligible in vitro, being renamed as DXL1 following recent nomenclature recommendation. DXL1 is targeted to plastids as DXS1, but shows a distinct expression pattern. The phenotypic analysis of a DXL1 defective mutant revealed that the function of the encoded protein is not essential for growth and development. Evolutionary analyses indicated that DXL1 emerged from DXS1 through a recent duplication apparently specific of the Brassicaceae lineage. Divergent selective constraints would have affected a significant fraction of sites after diversification of the paralogues. Furthermore, amino acids subjected to divergent selection and likely critical for functional divergence through the acquisition of a novel, although not yet known, biochemical function, were identified. Our results provide with the first evidences of functional specialization at both the regulatory and biochemical level within the plant DXS family.     

Assessment of HER-2 gene overexpression in Isfahan province breast cancer patients using Real Time RT-PCR and immunohistochemistry

Purpose

Overexpression of proto-oncogene HER-2 is one of the main molecular markers of breast cancer involved in prognosis and diagnosis and also in trastuzumab therapy. Thus, a request for the evaluation of HER-2 status in breast cancer has been increasing. The aim of our study was assessment of HER-2 overexpression in malignant and benign breast cancer specimens by Real Time RT-PCR technique and comparison of its results with IHC outcomes.

Methods

Twenty benign and sixty malignant breast cancers in addition to fifteen normal breast tissue specimens were analyzed by Real Time RT-PCR method. Fresh tissue samples were disrupted by mortar and pestle. A syringe and a needle were used for complete homogenization of the tissues. The RNA was then isolated from the samples and converted to cDNA. A standard curve was initially plotted using BioEasy SYBR Green I and then all 95 specimens were studied by Real Time RT-PCR using 2^− ΔΔCt method.

Results

23.3% of 60 malignant specimens showed HER-2 overexpression, while all of the benign samples represented the normal expression level of HER-2 gene. The concordance rate between the results of Real Time RT-PCR and IHC was 86.6%.

Conclusion

Real Time RT-PCR method is an almost reliable technique and at least can be used as a complementary method for confirming IHC results. This is emanated from relatively high rate of concordance between outcomes of IHC test, as a routine method of detecting the HER-2 gene expression status, and Real Time RT-PCR technique.     

Basic statistics and variational concepts behind the reverse Monte Carlo technique

We revise the statistical foundations of the reverse Monte Carlo (RMC) technique by constructing the associated functional of a variational principle which incorporates, without any ad hoc assumptions, the inherent errors accompanying the simulation and the experimental data. We propose a Bayesian criteria for acceptance/rejection of configurations, in terms of the variations of the functional. The loss function and variational functional minimization approaches are compared.     

PROcEED: Probabilistic reverse dosimetry approaches for estimating exposure distributions

As increasing amounts of biomonitoring survey data become available, a new discipline focused on converting such data into estimates of chemical exposures has developed. Reverse dosimetry uses a pharmacokinetic model along with measured biomarker concentrations to determine the plausible exposure concentrations-- a critical step to incorporate ground-truthing experimental data into a distribution of probable exposures that reduces model uncertainty and variability. At the population level, probabilistic reverse dosimetry can utilize a distribution of measured biomarker concentrations to identify the most likely exposure concentrations (or intake doses) experienced by the study participants. PROcEED is software that provides access to probabilistic reverse dosimetry approaches for estimating exposure distributions via a simple user interface.

Availability

PROcEED along with installation instructions is freely available for download from http://www.epa.gov/heasd/products/proceed/proceed.html     

Impact of Surface Active Compounds on Iron Catalyzed Oxidation of Methyl Linolenate in AOT–Water–Hexadecane Systems

Edible oils contain minor surface active components that form micro-heterogeneous environments, such as reverse micelles, which can alter the rate and direction of chemical reactions. However, little is known about the role of these micro-heterogeneous environments on lipid oxidation of bulk oil. Our objective was to evaluate the ability of water, cumene hydroperoxide, oleic acid, and phosphatidylcholine to influence the structure of reverse micelles in a model oil system: sodium bis(2-ethylhexyl) sulfosuccinate (aerosol-OT; AOT) in n-hexadecane. The influence of reverse micelle structure on iron catalyzed lipid oxidation was determined using methyl linolenate as an oxidizable substrate. The size and shape of the reverse micelle were investigated by small-angle x-ray scattering, and water contents was determined by Karl Fischer titrations. Lipid hydroperoxides and thiobarbituric acid reactive substances were used to follow lipid oxidation. Our results showed that AOT formed spherical reverse micelles in hexadecane. The size of the reverse micelles increased with increased water or phosphatidylcholine concentration, but decreased upon addition of cumene hydroperoxide or oleic acid. Iron catalyzed oxidation of methyl linolenate in the reverse micelle system decreased with increasing water concentration. Addition of phosphatidylcholine into the reverse micelle systems decreased methyl linolenate oxidation compared to control and reverse micelles with added oleic acid. These results indicate that water, cumene hydroperoxide, oleic acid, and phosphatidylcholine can alter reverse micelle size and lipid oxidation rates. Understanding how these compounds influence reverse micelle structure and lipid oxidation rates could provide information on how to modify bulk oil systems to increase oxidative stability.     

Medium chain carboxylic acids production from waste biomass: Current advances and perspectives

Alternative chemicals to diverse fossil-fuel-based products is urgently needed to mitigate the adverse impacts of fossil fuel depletion on human development. To this end, researchers have focused on the production of biochemical from readily available and affordable waste biomass. This is consistent with current guidelines for sustainable development and provides great advantages related to economy and environment. The search for suitable biochemical products is in progress worldwide. Therefore, this review recommends a biochemical (i.e., medium chain carboxylic acids (MCCAs)) utilizing an emerging biotechnological production platform called the chain elongation (CE) process. This work covers comprehensive introduction of the CE mechanism, functional microbes, available feedstock types and corresponding utilization strategies, major methods to enhance the performance of MCCAs production, and the challenges that need to be addressed for practical application. This work is expected to provide a thorough understanding of the CE technology, to guide and inspire researchers to solve existing problems in depth, and motivate large-scale MCCAs production.