Noninvasive subsurface analysis using multiple miniaturized Raman probes, part I: basic study of thin-layered transparent models of biomedical tissues

This study describes a basic theory for reconstructing pure Raman signals of materials composing a multilayer sample from Raman spectra obtained using two types of miniaturized Raman probes. An illustrative example is demonstrated using a multilayer system of samples composed of the transparent plastics polymethylmethacrylate (PMMA) and polyethylene (PE) as a model of thin-layered biomedical tissues. When the same region of an object is measured using Raman probes with different focal properties, the Raman spectra provide different depth profile information depending on the level of light penetration. Thus, a detailed comparison of the spectra can provide an interesting opportunity to probe the differences between the layers. A simple analytic form is presented for reconstructing the pure Raman spectra of the embedded layer. The method applies an understanding of the Raman sampling volume in layered transparent materials to the interpretation of Raman spectra experimentally measured by multiple probes. The basic theory described here is necessary for the expansion of the technique to turbid media, such as biological samples, where light-scattering effects must be considered. The potential applications of the proposed method include material and catalyst subsurface probing through different embedded materials, such as assessment of silicon wafers, effective noninvasive screening for catalyst synthesis, and biomedical tissue research.     

Kernel analysis of partial least squares (PLS) regression models

An analytical technique based on kernel matrix representation is demonstrated to provide further chemically meaningful insight into partial least squares (PLS) regression models. The kernel matrix condenses essential information about scores derived from PLS or principal component analysis (PCA). Thus, it becomes possible to establish the proper interpretation of the scores. A PLS model for the total nitrogen (TN) content in multiple Thai fish sauces is built with a set of near-infrared (NIR) transmittance spectra of the fish sauce samples. The kernel analysis of the scores effectively reveals that the variation of the spectral feature induced by the change in protein content is substantially associated with the total water content and the protein hydration. Kernel analysis is also carried out on a set of time-dependent infrared (IR) spectra representing transient evaporation of ethanol from a binary mixture solution of ethanol and oleic acid. A PLS model to predict the elapsed time is built with the IR spectra and the kernel matrix is derived from the scores. The detailed analysis of the kernel matrix provides penetrating insight into the interaction between the ethanol and the oleic acid.     

折叠之舞

这所住宅位于日本古老的首都--京都中心传统住宅街区内,由建筑师Kentaro Takeguchi+Asako Yamamoto/ALPHAVILLE共同设计建造。由于地区性建筑规范和邻里关系的制约,住宅外部延续了日本传统木制别墅的特征,尽量低调谦和地融入外部传统街区环境之中。当夜暮降临,透过住宅临街的木质格栅散透出柔和的暖光,晕染着这个     

Non-enzymatic, template-directed ligation of 2'-5' oligoribonucleotides. Joining of a template and a ligator strand

Decauridylate containing exclusively a 2'-5' phospho-diester bond ([2'-5']U10) served as a template for the synthesis of oligoadenylates [oligo(A)s] from the 5'-phosphorimidazolide of 2'-5' diadenylate (ImpA-2'p5'A). Joining of [2'-5']U10and ImpA2'p5'A also took place in substantial amounts to yield long-chain oligoribonucleotides in the template-directed reaction. An unusual CD spectrum ascribed to helix formation between [2'-5']U10and [2'-5'](pA)2was observed under the same conditions as that of the template-directed reaction. The 3'-5' linked decauridylate ([3'-5']U10) also promoted the template-directed synthesis of oligo(A)s from ImpA2'p5'A, but more slowly compared with [2'-5']U10. The results indicate that short-chain RNA oligomers with a 2'-5' phosphodiester bond could lead to longer oligoribonucleotides by template-directed chain elongation.     

The metabolic pathway of visual pigment chromophore formation in Drosophila melanogaster--all-trans (3S)-3-hydroxyretinal is formed from all-trans retinal via (3R)-3-hydroxyretinal in the dark

Carotenoid-depleted fruit flies, Drosophila melanogaster, were reared on yeast/glucose medium containing lipid-depleted white corn grits and cholesterol. After rearing for more than a year, the yield of flies remained constant and the content of 3-hydroxyretinal in a head was three logarithmic units less than that of normal flies reared on medium containing yellow corn grits. When all-trans retinal was supplied as the sole source of retinoids, the flies formed and accumulated all-trans 3-hydroxyretinal in the dark. To examine the metabolic pathway to produce (3S)-3-hydroxyretinal in Drosophila, all-trans retinal was supplemented for two hours to carotenoid-depleted flies in the dark, and the subsequent changes in the composition of 3-hydroxyretinal enantiomers were analyzed using a chiral column on HPLC. The results indicated initial formation of (3R)-3-hydroxyretinal followed by isomerization into the 3S enantiomer. In another set of experiments, the membrane fraction was obtained from the head homogenate of retinoid-depleted flies and an in vitro assay of 3-hydroxyretinal formation from retinal was performed. The 3-hydroxyretinal produced was the 3R enantiomer, supporting the result obtained from the in vivo experiment whereby (3S)-3-hydroxyretinal is produced from retinal via (3R)-3-hydroxyretinal. Addition of NADPH enhanced 3-hydroxyretinal formation and the presence of carbon monoxide inhibited it, suggesting that hydroxylation at the C3 position of retinal occurred via the monooxygenase activity of cytochrome P-450.     

AIGaAsSb Buffer/Barrier on GaAs substrate for InAs channel devices with high electron mobility and practical reliability

InAs/AlGaAsSb deep quantum well was successfully formed on GaAs substrate and examined for two electron devices, Hall elements (HEs), and field-effect transistors (FETs). With a thin buffer layer of 600 nm AIGaAsSb on GaAs substrate, we observed high electron mobility more than 23000 cm²/Vs and extrinsic effective electron velocity of 2.2 x 10⁷ cm/s for a 15 nm thick InAs channel at room temperature. AIGaAsSb lattice matched to InAs was discussed from the view points of insulating property, carrier confinement, and oxidization rate. Reliability data good enough for practical use were also obtained for HEs. We demonstrated AIGaAsSb as a promising buffer/barrier layers for InAs channel devices on GaAs substrate, and we discussed the possible advantages of AIGaAsSb also for InGaAs FETs.     

Six-month clinical and angiographic outcome of the new, less shortening Wallstent in native coronary arteries

BACKGROUND: The new, less shortening, self-expanding Wallstent is characterized by longitudinal flexibility, a protective membrane, a low profile, and a customized range of diameters (3.5 to 6.0 mm). The recent modification of the braiding angle of the Wallstent has resulted in a new device with less shortening on expansion and a concomitant reduction in radial force. We hypothesized that the enforced mechanical remodeling produced by the selection of an oversized Wallstent might result in improved accommodation of subsequent reactive intimal hyperplasia and prevention of chronic recoil of the vessel. METHODS AND RESULTS: To prove this hypothesis, we recently implanted 44 new, less shortening Wallstents in 35 native coronary arteries in 35 patients with acute or threatened closure after balloon angioplasty, according to a strategy of oversizing of Wallstent diameter and complete coverage of the lesion length. The initial and 6-month follow-up angiograms were analyzed with a computer-based quantitative coronary angiography (QCA) system. Acute gain (minimal luminal diameter [MLD] post minus MLD pre) and late loss (MLD post minus MLD at follow-up) were examined. Stent deployment was successful in 44 of 44 attempts (100%). Nominal stent diameter used was 1.40 mm larger than the maximal vessel diameter. One patient (3%) with a dilated but unstented lesion proximal to the stented segment sustained a subacute occlusion on day 1 associated with myocardial infarction. Event-free survival at 30 days after stent implantation was 97% (34 of 35 patients). Of the 34 patients eligible for 6-month angiographic follow-up, 3 who were asymptomatic declined repeat angiography. MLD (and percent diameter stenosis [% DS]) changed from 0.83 +/- 0.50 mm (72%) pre through 3.06 +/- 0.48 mm (15%) post to 2.27 +/- 0.74 mm (28%) at follow-up. Acute gain was 2.23 +/- 0.63 mm, and late loss was 0.78 +/- 0.61 mm. Angiographic restenosis ( > 50% DS) was observed in 5 of 31 patients (16%) at 6 months, all of whom underwent repeat angioplasty. Thus, the overall event-free survival at 6-month follow-up was 83% (29 of 35 patients). CONCLUSIONS: The oversized Wallstent implantation with complete coverage of the lesion length conveyed a favorable 6-month clinical and angiographic outcome. The large acute gain obtained by the Wallstent afforded greater accommodation of the subsequent late loss. The enforced mechanical remodeling by oversized new Wallstents may result in prevention of acute and chronic recoil of the vessel wall and subsequently a lower restenosis rate at follow-up.     

Increased prevalence of luteinizing hormone beta-subunit variant in Japanese infertility patients

To determine the frequency of a common luteinizing hormone variant in a Japanese population and to evaluate its significance in infertility, serum samples were collected from 169 healthy non-pregnant Japanese women, 105 healthy adult Japanese men and 97 female Japanese infertility patients. The luteinizing hormone variant includes two point mutations in the beta-subunit gene (Trp8 to Arg8 and Ile15 to Thr15). DNA from blood cells was studied in 10 healthy women, 10 men and five patients using polymerase chain reaction and direct sequencing. In immunoassays, results with a monoclonal antibody recognizing only the wild-type hormone and a polyclonal antibody recognizing the variant as well were compared as a ratio; ratios in heterozygotes and in individuals with only wild-type alleles ranged from 0.19 to 0.50 and from 0.56 to 1.21, respectively, and 0.50 was considered a 'cut-off' value for identifying individuals with the variant. For the larger subject groups, the frequency of the variant was 9.5% in normals. The mean ratio (0.80 +/- 0.35) in infertility patients was significantly lower (P < 0.01) than in healthy women (1.09 +/- 0.56), and the variant occurred more frequently in infertility patients (16.5%) than in healthy women (8.3%; P < 0.05). The variant was more frequent in patients with ovulatory disorders (43.8%) than other patients (16.0%; P < 0.05).     

Quantification of sphingosine derivatives in human platelets: inducible formation of free sphingosine

OBJECTIVE: This study aimed to investigate the incidence of cystoid macular edema and anterior uveitis associated with the use of latanoprost. DESIGN: A retrospective review of patients treated with latanoprost in the authors' practice between September 1, 1996, and August 1, 1997, was performed. PARTICIPANTS: Ninety-four patients and 163 eyes were studied. INTERVENTION: Patients presenting with signs and symptoms of ocular inflammation while receiving latanoprost were noted, and their response to the discontinuation of the drug was recorded. MAIN OUTCOME MEASURES: The presence and degree of anterior uveitis and cystoid macular edema were measured. RESULTS: Six (6.4%) of 94 patients (8 [4.9%] of 163 eyes) had anterior uveitis develop, and 2 (2.1%) of 94 patients (2 [1.2%] of 163 eyes) had cystoid macular edema develop while being treated with latanoprost. CONCLUSION: Although latanoprost is an effective ocular-hypotensive agent, the authors' experience with the drug has shown a significant incidence of anterior uveitis and cystoid macular edema. To the authors' knowledge, this is the first study to report the incidence of both cystoid macular edema and anterior uveitis associated with latanoprost therapy. Treating physicians should be aware of these potential complicating side effects of latanoprost.     

Basic fibroblast growth factor is neither necessary nor sufficient for the development of retinal neovascularization

Basic fibroblast growth factor (FGF2) is constitutively expressed in the retina and its expression is increased by a number of insults, but its role in the retina is still uncertain. This study was designed to test the hypothesis that altered expression of FGF2 in the retina affects the development of retinal neovascularization. Mice with targeted disruption of the Fgf2 gene had no detectable expression of FGF2 in the retina by Western blot, but retinal vessels were not different in appearance or total area from wild-type mice. When FGF2-deficient mice were compared with wild-type mice in a murine model of oxygen-induced ischemic retinopathy, they developed the same amount of retinal neovascularization. Transgenic mice with a rhodopsin promoter/Fgf2 gene fusion expressed high levels of FGF2 in retinal photoreceptors but developed no retinal neovascularization or other abnormalities of retinal vessels; in the ischemic retinopathy model, they showed no significant difference in the amount of retinal neovascularization compared with wild-type mice. These data indicate that FGF2 expression is not necessary nor sufficient for the development of retinal neovascularization. This suggests that agents that specifically antagonize FGF2 are not likely to be useful adjuncts in the treatment of retinal neovascularization and therapies designed to increase FGF2 expression are not likely to be complicated by retinal neovascularization.