Light exposure required for optimum conversion of light activated resin systems

OBJECTIVE: The aim of this study was to evaluate the relationship between the degree of conversion (DC) of composites and the light intensity using LED-curing units and also to determine the amount of exposure required to achieve optimal curing. METHOD: The light outputs of light-curing units and the depths of cure of composites exposed to these units were determined using the methods outlined in modified ISO standards, ISO/TS10650 and ISO 4049, respectively. The distributions of DC in composites were investigated by IR spectra of microareas obtained at various depths from the irradiated surface of thin specimens cut out from the cured composites. IR spectra were measured using a Fourier transform infrared spectrometer equipped with a microscopic unit. DC was calculated from the changes in the amount of C=C double bonds in the IR spectra. RESULTS: The light intensity at various depths through the cured composite was calculated from the attenuation coefficient of each material, obtained from the linear relationship between the depth of cure and the logarithm of the amount of exposure, which is defined as the product of the irradiance and irradiation time. There was a third or fourth order regression relationship between DC and the logarithm of total light energy at a particular depth. SIGNIFICANCE: The minimum light energy required to produce a saturated DC was about 1000 s mW/cm2.     

金地鼠颊囊癌模型PCNA,BrdU及光镜观察结果的相关分析

癌变的早期诊断对提高疗效具有特殊意义，为了寻求简捷，高效，超前，可靠的诊断方法，实验以ＤＭＢＡ（二甲基苯并蒽）诱导的金地鼠颊囊致癌模型为对象，以ＰＣＮＡ（增殖细胞核抗原）ＢｒｄＶ（溴脱氧尿嘧啶）等免疫组化技术为手段；以光镜观察诊断为对照，对三种观察结果进行相关分析，发现三者间有高度显著的相关性，证实了免疫组化方法在癌变诊断中有一定的参考价值，实验还发现ＰＣＮＡ和ＢｒｄＵ检测结果比较每天敏感，简捷，     

Characterization of genomic rearrangements of the alpha1-acid glycoprotein/orosomucoid gene in Ghanaians

In this study, the structure of the α₁-acid glycoprotein (AGP), or orosomucoid (ORM), gene was investigated in a Ghanaian mother and her child, who shared an unusual variant, ORM1 S2(C), found by isoelectric focusing. Three remarkable changes of nucleotide sequence were observed: (1) The two ORM1 alleles, ORM1 ^* S and ORM1 ^* S2(C), had the AGP2 gene-specific sequence at one and three regions, respectively, in exon 5 to intron 5. The variant allele originating from ORM1 ^* S was characterized by a G-to-A transition, resulting in an amino acid change from valine to methionine, which is also detected in ORM1 F2, a form that is common in Europeans. (2) The AGP2 gene of the child, inherited from the father, was duplicated, as revealed by long-range polymerase chain reaction. (3) Three new mutations were observed in two exons of the AGP2 genes of the mother and child. All of these novel genomic rearrangements, which were not observed in Japanese subjects, may have arisen through point mutation, gene conversion, and unequal crossover events. It is likely that the rearrangement of the AGP gene has often occurred in Africans. Received: June 15, 2001 / Accepted: July 10, 2001     

Frequency-to-voltage conversion in the pyramidal tract neuron: an important role of the inhibitory postsynaptic potential

Frequency-coded impulses are known to be converted into postsynaptic potentials (PSPs) at the synapse of a target neuron. This can be termed frequency-voltage (F-V) conversion. Studies on this problem in pyramidal tract neurons (PTNs) showed that not only the amplitude but also the duration of depolarizing PSPs was determined as a function of the input impulse frequency. Two opposite patterns of F-V conversion were observed following activation of two input systems to PTNs. Inhibitory postsynaptic potentials were found to play an important role in the regulation of the duration of PSPs by curtailing excitatory post-synaptic potentials.     

Identification of a novel allele HLA-B*7805 in a Japanese female

A new HLA-B*78 allele, B*7805, was identified in a healthy Japanese female. The results of her serological HLA class I typing showed an unusual Bw4/Bw6 pattern with strongly positive reactivity to anti-Bw6, i.e. A24, -, B52, -, Bw4, Bw6. In DNA typing, she was typed as A*24, -, B*52, B*78-like, Cw1202, -, (Bw4, Bw6). Cloning and sequencing of exon 2 and exon 3 of her B locus genes revealed a new allele B*7805. The cloned B*7805 differed from B*78021 by three nucleotide substitutions in exon 2 at position 259 (A to G), 261 (C to G) and 272 (A to C), and contained sequences defining Bw6 motif in the region of codon 77 to 83.     

CORDIC算法在B超数字扫描变换器中的应用

数字扫描变换器在B型超声诊断仪的应用，能使现代实时B型超声诊断仪实现一些新的诸如图像冻结、多帧贮存、数据测量计算和TV显示等功能。在设计B型超声诊断仪中数字扫描变化器的过程中，直角坐标到极坐标变换是一个关键的技术，本研究论述了应用在数字扫描变化器中的一种新的算法——CORDIC算法，对该算法的原理进行了简介，将CORDIC算法应用到直角——极坐标变换中，并进行了算法修正和公式计算。根据其具体的应用对该算法进行了优化，并给出了算法的硬件实现结构。最后，对算法进行了软件仿真，并给出了结果分析。     

Peripheral progesterone (P) levels and endometrial response to various dosages of vaginally administered P in estrogen-primed women

Objective: To compare the pharmacokinetics and pharmacodynamics of 100 mg/d, 200 mg/d, and 400 mg/d (200 mg two times per day) of P administered vaginally for 14 days to estrogen-primed postmenopausal women.Design: Randomized, open-label, three-way crossover study.Setting: Two university-based investigative sites.Patient(s): Twenty healthy postmenopausal women with histologically normal endometria.Intervention(s): Oral 17,β-E₂ was given each day of a 28-day cycle; a P vaginal suppository was inserted daily according to the randomization schedule during days 15–28 of each cycle; blood samples were collected; an endometrial biopsy was obtained on day 25; and patients were crossed over to the next treatment cycle after a washout period of at least 30 days.Main Outcome Measure(s): Mean P blood levels, endometrial dating/conversion.Result(s): There was good vaginal absorption of P for all dosages. Endometrial conversion occurred in all 200- and 400-mg/d P-dosed cycles, whereas the 100-mg/d dosage failed to convert primed endometria consistently. There also was a significantly increased tendency for earlier bleeding and spotting with the 100-mg/d dosage.Conclusion(s): Both the 200- and 400-mg/d dosage regimens consistently convert an estrogen-primed endometrium, and yield appropriate endometrial dating and bleeding patterns. However, the 400-mg/d dosage attains the highest sustained blood levels and may be the best dosage regimen for further study.     

Reverse mutations – spontaneous amelioration or cure of inherited disorders?

Some recent publications indicate that inherited disorders can ameliorate or possibly disappear if mutations responsible for the disease revert to normal. This review tries to summarize our current knowledge about reverse mutations as this information may be of special interest for attempts at somatic gene therapy. Received: 14 July 1997 / Accepted: 2 March 1998     

Reflex sympathetic dystrophy in a 12-year-old twin with comorbid conversion disorder in both twins

A case of reflex sympathetic dystrophy is presented in a 12-year-old girl with comorbid conversion disorder. Her identical twin also had a conversion disorder. This is the first reported case of coexistence of reflex sympathetic dystrophy and conversion disorder. It is important for clinicians to be aware that these conditions may coexist since the presentation of symptoms differ, even though there are shared features of treatment.     

Topology Optimization of Piezoelectric Energy Harvesters for Enhanced Open-Circuit Voltage Subjected to Harmonic Excitations

Energy harvesting devices made of piezoelectric material are highly anticipated energy sources for power wireless sensors. Tremendous efforts have been made to improve the performance of piezoelectric energy harvesters (PEHs). Noticeably, topology optimization has shown an attractive potential to design PEHs with enhanced energy conversion efficiency. In this work, an alternative yet more practical design objective was considered, where the open-circuit voltage of PEHs is enhanced by topologically optimizing the through-thickness piezoelectric material distribution of plate-type PEHs subjected to harmonic excitations. Compared to the conventional efficiency-enhanced designs, the open-circuit voltage of PEHs can be evidently enhanced by the proposed method while with negligible sacrifice on the energy conversion efficiency. Numerical investigations show that the voltage cancellation effect due to inconsistent voltage phases can be effectively ameliorated by optimally distributed piezoelectric materials.