Design of Biotin-Functionalized Luminescent Quantum Dots

We report the design and synthesis of a tetraethylene glycol- (TEG-) based bidentate ligand functionalized with dihydrolipoic acid (DHLA) and biotin (DHLA—TEG—biotin) to promote biocompatibility of luminescent quantum dots (QD's). This new ligand readily binds to CdSe—ZnS core-shell QDs via surface ligand exchange. QDs capped with a mixture of DHLA and DHLA—TEG—biotin or polyethylene glycol- (PEG-) (molecular weight average ∼600) modified DHLA (DHLA—PEG600) and DHLA—TEG—biotin are easily dispersed in aqueous buffer solutions. In particular, homogeneous buffer solutions of QDs capped with a mixture of DHLA—PEG600 and DHLA—TEG—biotin that are stable over broad pH range have been prepared. QDs coated with mixtures of DHLA/DHLA—TEG—biotin and with DHLA—PEG600/DHLA—TEG—biotin were tested in surface binding assays and the results indicate that biotin groups on the QD surface interact specifically with NeutrAvidin-functionalized microtiter well plates

Enhanced enzymatic activity from phosphotriesterase trimer gold nanoparticle bioconjugates for pesticide detection

The rapid detection of organophosphates (OPs), a class of strong neurotoxins, is critically important for monitoring acute insecticide exposure and potential chemical warfare agent use. Herein, we improve the enzymatic activity of a phosphotriesterase trimer (PTE3), an enzyme that selectively recognizes OPs directly, by conjugation with distinctly sized (i.e., 5, 10, and 20 nm diameter) gold nanoparticles (AuNPs). The number of enzymes immobilized on the AuNP was controlled by conjugating increasing molar ratios of PTE3 onto the AuNP surface via metal affinity coordination. This occurs between the PTE3-His6 termini and the AuNP-displayed Ni2+-nitrilotriacetic acid end groups and was confirmed with gel electrophoresis. The enzymatic efficiency of the resultant PTE3–AuNP bioconjugates was analyzed via enzyme progress curves acquired from two distinct assay formats that compared free unbound PTE3 with the following PTE3–AuNP bioconjugates: (1) fixed concentration of AuNPs while increasing the bioconjugate molar ratio of PTE3 displayed around the AuNP and (2) fixed concentration of PTE3 while increasing the bioconjugate molar ratio of PTE3–AuNP by decreasing the AuNP concentration. Both assay formats monitored the absorbance of p-nitrophenol that was produced as PTE3 hydrolyzed the substrate paraoxon, a commercial insecticide and OP nerve agent simulant. Results demonstrate a general equivalent trend between the two formats. For all experiments, a maximum enzymatic velocity (Vmax) increased by 17-fold over free enzyme for the lowest PTE3–AuNP ratio and the largest AuNP (i.e., ratio of 1[thin space (1/6-em)]:[thin space (1/6-em)]1, 20 nm dia. AuNP). This work provides a route to improve enzymatic OP detection strategies with enzyme–NP bioconjugates

Effects of shell thickness on the electric field dependence of exciton recombination in CdSe/CdS core/shell quantum dots

Here we examine the effects of shell thickness on the photophysical properties of CdSe/CdS core/shell quantum dots (QDs) in an electric field. Photoluminescence (PL) of QDs in an applied electric field is observed to decrease markedly with increasing shell thickness, with a thick-shelled (4.9 nm shell) sample exhibiting an order of magnitude greater PL suppression than a thin-shelled sample (1.25 nm shell) with the same core

Retrospective Comparison of Non-Skin-Sparing Mastectomy and Skin-Sparing Mastectomy with Immediate Breast Reconstruction

Background. We compared Skin-sparing mastectomy (SSM) with immediate breast reconstruction and Non-skin-sparing mastectomy (NSSM), various types of incision in SSM. Method. Records of 202 consecutive breast cancer patients were reviewed retrospectively. Also in the SSM, three types of skin incision were used. Type A was a periareolar incision with a lateral extension, type B was a periareolar incision and axillary incision, and type C included straight incisions, a small elliptical incision (base line of nipple) within areolar complex and axillary incision. Results. Seventy-three SSMs and 129 NSSMs were performed. The mean follow-up was 30.0 (SSM) and 41.1 (NSSM) months. Respective values for the two groups were: mean age 47.0 and 57; seven-year cumulative local disease-free survival 92.1% and 95.2%; post operative skin necrosis 4.1% and 3.1%. In the SSM, average areolar diameter in type A & B was 35.4 mm, 43.0 mm in type C and postoperative nipple-areolar plasty was performed 61% in type A & B, 17% in type C, respectively. Conclusion. SSM for early breast cancer is associated with low morbidity and oncological safety that are as good as those of NSSM. Also in SSM, Type C is far superior as regards cost and cosmetic outcomes

A Flacci-flabby Bending Pencil : How and why does visible flexion occur?

エンピツの端に近いところを親指と人差し指でゆるく支えて水平にし、波うつように上下に揺らすとエンピツがゴムの棒のようにへなへなと僥って見える。この錯視現象はラバー・ペンシル イリュージョン（Rubber Pencil Illusion: RPI）と呼ばれている。本研究では過去、本学において行われたRPIにかんする研究を紹介し、視的僥いの発生について考察した。先ず、対象に内在するキネマティックスを"見る"視覚系の機能特性、そしてそれらの機能が発生後いつごろまでに形成されていくのかについて考察した。次に、玉井（1987）；北野（1996）らによるRPIの運動波形の解析、永井（1981）によるRPI発生装置の作成、北野（1996）；畦布・平岡(1998)；原（1998）らの実験的アプローチによるRPIの現象観察が報告された。また、視覚的機能である視覚的持続の観点から、RPIの現象発生について現象観察を踏まえながら考察した。最後に我々がRPIを興味深い、あるいはおもしろいと感じる感性について考察した。If we loosely hold the end of a pencil with a thumb and an index finger and wave it up and down, we can then see that the pencil appears flaccid and flabby, like a stick of rubber. This illusionary phenomenon is called the rubber pencil illusion (RPI). This study reports some researches on RPI experiments performed in our laboratory, and discusses the mechanism of the apparent flexibility. First, we consider the properties of visual functions that we see in kinematics, which are inherent in an object, and determine when such functions develop after birth. Next, we report the analysis of the loci of RPI movement by Tamai (1987) and Kitano (1996), the creation of RPI generating equipment by Nagai (1981), and the observations performed by Kitano (1996) and Azefu and Hiraoka (1998). We also consider the generation of RPI from the viewpoint of an important property of the visual system: visible persistence. Finally, we analyze the sensory impressions of RPI from the viewpoint of the properties of visual functions

A Nanobody‐on‐Quantum Dot Displacement Assay for Rapid and Sensitive Quantification of the Epidermal Growth Factor Receptor (EGFR)

Biosensing approaches that combine small, engineered antibodies (nanobodies) with nanoparticles are often complicated. Here, we show that nanobodies with different C-terminal tags can be efficiently attached to a range of the most widely used biocompatible semiconductor quantum dots (QDs). Direct implementation into simplified assay formats was demonstrated by designing a rapid and wash-free mix-and-measure immunoassay for the epidermal growth factor receptor (EGFR). Terbium complex (Tb)-labeled hexahistidine-tagged nanobodies were specifically displaced from QD surfaces via EGFR-nanobody binding, leading to an EGFR concentration-dependent decrease of the Tb-to-QD Förster resonance energy transfer (FRET) signal. The detection limit of 80±20 pM (16±4 ng mL−1) was 3-fold lower than the clinical cut-off concentration for soluble EGFR and up to 10-fold lower compared to conventional sandwich FRET assays that required a pair of different nanobodies

Clinical Evaluation with Referrence to Operative Specificity on Tracheal and Bronchial Reconstruction

The clinical specificity were evaluated in those 11 cases who underwent tracheal recon - structive surgery and in those 25 cases who underwent bronchial reconstructive surgery respectively. Its prognosis after tracheal reconstruction at the level of intrathoracic region was extremely poor. The operative specificity with regard to tracheal surgery consist of being a poor genera- condition preoperativelly and of having an urgent demand of removal of tracheal stenotic lesion to alleviate respiratory distress . The prognosis after tracheal surgery was commonly poor and was similar to that after emergency operation as a general accep - tance for the reason of unfavorable general condtion . The present study was to define clinical problems in which the salvage after tracheal surgery was entirely difficult. The improvement of the prognosis following tracheal surgery should be found in maximum endeavor for prevention of postoperative complication related to operative death intimately. However, terminal tracheostomy employed for lesions of cervical trachea was one o

The Effect of Surgical Repair for Pectum Excavatum on Cardiopulmonary Function

In five patients with corrective surgery for pectus Excavatum, the effectiveness of surgical repair were evaluated from the results of pulmonary function test as well as the finding on ECG according to follow-up study postoperativelly. Of five patient undergone the corrective surgery which sternoturnover with costalplasty employed in 4, and sternoplasty alone in I, all of them were male and the average age except 3 years of age was 14.8 years ranging from 10 to 21 years. There are no manifestation of clinical syndrome in all 5 cases. However, the fair mental growth demands psychologically the early corrective surgery in young chidren. By follow-up study after surgical correction for pectus excavatum during a period from 3 months to 3 years and 3 months, the finding on EKG of right ventricular overload revealed the improvement within 2 months after surgical correction in contrast the results of pulmonary function test disclosed no marked changes until 2 months following surgery. From the view of cosmetic efficacy of corrective surgery, sternoturnover with or without costalplasty are one of the adovocating operative procedures

Terbium to Quantum Dot FRET Bioconjugates for Clinical Diagnostics: Influence of Human Plasma on Optical and Assembly Properties

Förster resonance energy transfer (FRET) from luminescent terbium complexes (LTC) as donors to semiconductor quantum dots (QDs) as acceptors allows extraordinary large FRET efficiencies due to the long Förster distances afforded. Moreover, time-gated detection permits an efficient suppression of autofluorescent background leading to sub-picomolar detection limits even within multiplexed detection formats. These characteristics make FRET-systems with LTC and QDs excellent candidates for clinical diagnostics. So far, such proofs of principle for highly sensitive multiplexed biosensing have only been performed under optimized buffer conditions and interactions between real-life clinical media such as human serum or plasma and LTC-QD-FRET-systems have not yet been taken into account. Here we present an extensive spectroscopic analysis of absorption, excitation and emission spectra along with the luminescence decay times of both the single components as well as the assembled FRET-systems in TRIS-buffer, TRIS-buffer with 2% bovine serum albumin, and fresh human plasma. Moreover, we evaluated homogeneous LTC-QD FRET assays in QD conjugates assembled with either the well-known, specific biotin-streptavidin biological interaction or, alternatively, the metal-affinity coordination of histidine to zinc. In the case of conjugates assembled with biotin-streptavidin no significant interference with the optical and binding properties occurs whereas the histidine-zinc system appears to be affected by human plasma

A 100%-complete sequence reveals unusually simple genomic features in the hot-spring red alga Cyanidioschyzon merolae

<p>Abstract</p> <p>Background</p> <p>All previously reported eukaryotic nuclear genome sequences have been incomplete, especially in highly repeated units and chromosomal ends. Because repetitive DNA is important for many aspects of biology, complete chromosomal structures are fundamental for understanding eukaryotic cells. Our earlier, nearly complete genome sequence of the hot-spring red alga <it>Cyanidioschyzon merolae </it>revealed several unique features, including just three ribosomal DNA copies, very few introns, and a small total number of genes. However, because the exact structures of certain functionally important repeated elements remained ambiguous, that sequence was not complete. Obviously, those ambiguities needed to be resolved before the unique features of the <it>C. merolae </it>genome could be summarized, and the ambiguities could only be resolved by completing the sequence. Therefore, we aimed to complete all previous gaps and sequence all remaining chromosomal ends, and now report the first nuclear-genome sequence for any eukaryote that is 100% complete.</p> <p>Results</p> <p>Our present complete sequence consists of 16546747 nucleotides covering 100% of the 20 linear chromosomes from telomere to telomere, representing the simple and unique chromosomal structures of the eukaryotic cell. We have unambiguously established that the <it>C. merolae </it>genome contains the smallest known histone-gene cluster, a unique telomeric repeat for all chromosomal ends, and an extremely low number of transposons.</p> <p>Conclusion</p> <p>By virtue of these attributes and others that we had discovered previously, <it>C. merolae </it>appears to have the simplest nuclear genome of the non-symbiotic eukaryotes. These unusually simple genomic features in the 100% complete genome sequence of <it>C. merolae </it>are extremely useful for further studies of eukaryotic cells.</p