Stability of centrosome numbers in poly(ADP-ribose) polymerase-1- and poly(ADP-ribose) glycohydrolase-deficient mouse ES cells

Poly(ADP-ribose) polymerase-1 (Parp-1) localizes mainly in the nucleus and functions in DNA repair, genome stability and cell death regulation. Meanwhile, it also localizes in centrosomes and is involved in the regulation of centrosome duplication. An abnormal increase in centrosome numbers is frequently observed in Parp-1-deficient (Parp-1^−/−) mouse embryonic fibroblasts (MEFs) (Kanai et al. (2003) Mol. Cell. Biol. 23, 2451–2462). However, there are no studies on whether the centrosome abnormality occurs also in other cell types under Parp-1 deficiency. In this study, we report that Parp-1^−/− mouse embryonic stem (ES) cell lines did not show an abnormally increased number of centrosomes compared to wild-type ES cells. Recently, poly(ADP-ribose) glycohydrolase (Parg) has also been shown to localize in centrosomes (Ohashi et al. (2003) Biochem. Biophys. Res. Commun. 307, 915–921). The number of centrosomes of Parg-deficient (Parg^−/−) ES cells was also analyzed in this study and was found to be stable under Parg deficiency. We also examined centrosome numbers in wild-type, Parp-1^−/− and Parg^−/− ES cell lines after treatment with methylmethanesulfonate (MMS) or γ-irradiation. Although a slight increase in the number of centrosomes is observed in each genotype twenty-four hours after treatment with MMS at 50 μM or with γ-irradiation at 1.4 Gy, there was no difference among the genotypes. These results suggest that loss of Parp-1 and Parg is insufficient to induce abnormality in centrosome numbers in ES cells and that ES cells possibly possess a strict mechanism for the maintenance of a normal number of centrosomes.     

Microfabricated polydimethylsiloxane microfluidic system including micropump and microvalve for integrated biosensor

We present a microfluidic system with paraffin-actuated microvalves and a thermopneumatic-actuated micropump that are easily integrated on the same substrate using the same fabrication process. The fabrication process of this microfluidic system using polydimethylsiloxane (PDMS), indium tin oxide (ITO) and glass is relatively simple, and its performance is good for the application of the disposable lab-on-a-chip. A maximum pumping rate of about 2.0 μl/min was measured at a duty ratio of 5% and a frequency of 1 Hz. The flow cut-off powers for the microvalves with the channel depth of 220 μm, were 300 and 350 mW for valve seat diameters of 1.5 and 2.0 mm, respectively. The power for flow cut-off depends on the channel depth and the diameter of the valve seat in the microvalves.     

Second-Harmonic Generation in Domain-Inverted Grating Induced by Focused Ion Beam

The fabrication of a periodic domain inversion in LiTaO₃ and LiNbO₃ using direct ion-beam writing is presented. The polarization of these materials can be reversed at room temperature by irradiating Si²⁺ ions into +c faces. A first-order periodic domain inversion with a 50% duty cycle, a depth of 300μ, and an interaction length of 1 mm was realized in LiTaO₃. Using this structure, 300μW of blue light was generated for a conversion efficiency of 0.25%/W.     

Quasi-continuous-wave operation of AlGaAs/GaAs quantum cascade lasers

Quasi-continuous-wave operation of AlGaAs/GaAs-based quantum cascade lasers (λ9 μm) up to 165 K is reported. The strong temperature dependence of the threshold current density and its higher value in high duty cycle is investigated in detail. The self-heating effect in the active region is explored by changing the operating duty cycles. The degradation of lasing performance with temperature is explained.     

Surface foaming of collagen, chitosan and other biopolymer films by KrF excimer laser ablation in the photomechanical regime

Collagen, an important material made of a protein of the extracellular matrix, was extracted from rat tail tendons by acetic acid dissolution, and dry glassy films (15% water content) with smooth surfaces were casted from the solution with a thickness of ∼25 μm. Collagen and similar biopolymer films surface were exposed to single pulses of radiation of the KrF laser with increasing fluence. A white damaged area appears on the treated surface at a threshold of 0.5 J/cm² with a single pulse and becomes more visible for higher fluence. SEM and profilometry of the ablated surface displays an important swelling (∼5–7 μm) and a microscopic foam structure indicative of the laser induced expansion of the excited material. This process is due to the explosive ablation (a critical phenomenon also called explosive boiling or phase explosion) of the irradiated material and produces upon laser heating a high concentration of bubbles within the polymer because of the relatively large absorption depth (20 μm) and the presence of a large amount of water in the material. Further bubble colliding and bursting produces a three-dimensional polymer micro-foam with interconnected pores. This is the first this result has been reported. The laser induced micro-foam may display some interesting properties for new applications. PACS 42.62; 61.82; 42.70-aThis revised version was published online in June 2005 with corrections to equations 7, 9 and 10.     

The biological significance of ω-oxidation of fatty acids

The author focuses on the biological significance of ω-oxidation of fatty acids. Early studies revealed that there is a subsidiary pathway for β-oxidation of fatty acids when β-oxidation is blocked. Many studies demonstrated that the ω-oxidation serves to provide succinyl-CoA for the citric acid cycle and for gluconeogenesis under conditions of starvation and diabetes. Acylglucosylceramides which are composed of linoleic acid, long chain ω-hydroxy fatty acids, eicosasphingenine (or trihydroxyeicosasphingenine) and glucose, are responsible for normal epidermal permeability function in the skin. It is observed that ω- and (ω-1)-oxidation of fatty acids are related to energy metabolism in some laboratory animals such as musk shrews and Mongolian gerbils. Studies confirmed that ω- and (ω-1)-oxidation of fatty acids play crucial roles in the production of insect pheromones of honeybees and in the formation of biopolyesters of higher plants. In addition, the biological significance of ω-oxidation of prostaglandins and leukotrienes is described.     

Functional Changes in the Care-needing Elderly after Surface Electrical Stimulation to the Abdomen

Background: Strength of the trunk muscles is a key component of motor control, but it declines easily with the process of aging and/or disuse. Objectives: To investigate the effects of surface electrical stimulation (ES) to the abdominal muscles and the motor performance for care-needing elderly. Design: Controlled trial. Participants: Twenty-one elderly people (60–90 years) with care-needing, who were admitted to a nursing home or hospital for daily care and their score of Barthel Index had been stable from 55.3 ± 19.4 to 55.3 ± 19.8 during 3 months before intervention. Intervention: Common physical/occupational therapy was performed for all of the subjects during the study period. ES was applied to the abdomen of 15 subjects (ES group) twice a day for 8 weeks. Measurements: Functional measurements were performed before and after beginning of the study with some parameters as follows: grip strength; movement time for sitting up (MSU); maximum walking speed (WS). Results: No significant differences between two groups were noted for characteristics at baseline. In the ES group, MSU (from 21.1 ± 21.4 to 10.4 ± 8.3 sec) significantly improved (p < 0.05) after 8weeks. WS (from 17.7 ± 12.1 to 24.3 ± 15.3 m/min) were also improved (p < 0.05) after 8 weeks. Limitations: A limitation of this study was the small sample size. Conclusions: ES to the abdominal area has the potential to improve motor function in the care-needing elderly through reinforcement of the abdominal muscles.     

A compact 1.06/1.32/2.94 μm pulsed laser for dentistry

A three-wavelength pulsed laser for dental application is developed. The laser houses the Nd:YAG resonator (1.06/1.32 μm) for soft-tissue treatment and Er:YAG resonator (2.94 μm) for caries removal and fits and fissure treatment. Two heads share the cooling unit and two identical high-voltage power supply modules in order to achieve compactness. The Nd:YAG laser has 10 W at 1.06 μm and 7 W at 1.32 μm with a pulse duration of 100 μs. An Er:YAG laser of 2.94 μm has 3.5 W, 20 Hz and a pulse duration of 250 μs. The beams are delivered through fibers and the laser size is 75×55×32.5 cm.     

Molecular orientation and morphology of contact printed α-quaterthiophene films on gold

We present contact printing as a technique to deposit α-quaterthiophene (α-4T) films from the solid phase onto gold. The molecular orientation and morphology of both the printed film and the original polycrystalline α-4T film on silica were investigated with low energy ion scattering (LEIS), atomic force microscopy (AFM), X-ray diffraction (XRD) and optical microscopy. We show that the strong interaction between clean gold and α-4T induces a drastic change in the molecular orientation and morphology of a 380 nm thick α-4T film. On gold the α-4T molecules are orientated with the thiophene rings parallel to the substrate and form rod-like crystallites (typically 13×1.3 μm²), whereas on silica α-4T molecules stand almost upright and form large cobblestone-like crystallites (typical diameter 10 μm). Exposure of α-4T to a low energy ion beam (dose <1×10¹⁴ 3 keV ³He⁺ ions/cm²) prior to printing causes polymerisation, which decreases the ability to print and alters the morphology of the printed film.     

Effects of pulse electrodeposition parameters on the properties of Ni-TiO2 nanocomposite coatings

The aim of this study is to investigate the effects of pulse electrodeposition parameters on the properties of nickel-titania composite coatings electrodeposited from a nickel Watts type bath. The effects of average current density, frequency and duty cycle on the surface morphology, crystal size, preferred orientation of the deposits and the amount of embedded nano-TiO₂ particles in the composite coatings were investigated. The results represented the optimum amount of average current density (e.g., 4 A dm⁻²) for obtaining the highest volume percentage of the incorporated titania particles and subsequently the maximum microhardness. Moreover, by increasing the frequency up to 10 Hz while reducing the duty cycle to 10% at constant peak current density, the volume percentage of particles increased to about 7% which is almost twice as much the volume percentage as deposited particles in direct current method. According to the results the composite coating exhibited obviously [1 0 0] + [2 1 1] as preferred orientation at low pulse frequency and the diffraction intensity of the [2 1 1] fiber orientation is increased, probably due to the pH increase adjacent to the electrolyte/cathode interface at higher frequencies. Also, it has been found that by reduction in the duty cycle, more titania particles were incorporated in the composite coatings and this promoted the nickel crystals growth on [1 0 0] planes and consequently the coatings preferred orientation changed from the [2 1 1] to [1 0 0] + [2 1 1] planes.     

All-optical NRZ-OOK-to-RZ-OOK format conversions with tunable duty cycles using nonlinear polarization rotation of a semiconductor optical amplifier

We experimentally demonstrate an all-optical 10 Gb/s format conversion from non-return-to-zero (NRZ) on-off-keying (OOK) to return-to-zero (RZ)-OOK with tunable duty cycle in the whole C-band using nonlinear polarization rotation (NPR) arising in an semiconductor optical amplifier (SOA). The experimental results show that, by tuning the polarizer at the SOA output, an RZ signal with tunable duty cycle from 33% to 66% could be obtained with an extinction ratio(ER) over 10 dB. In addition, we show that the NRZ-to-RZ conversion with duty cycle of 33-66% can be obtained with less than 1 dB power penalty at the bit error ratio (BER) of 10⁻⁹. The device can facilitate the cross-connection between optical transmission networks employing different modulation formats.     

Heat Transfer and Fluid Flow Characteristics of Microchannel with Oval-Shaped Micro Pin Fins

A novel microchannel heat sink with oval-shaped micro pin fins (MOPF) is proposed and the characteristics of fluid flow and heat transfer are studied numerically for Reynolds number (Re) ranging from 157 to 668. In order to study the influence of geometry on flow and heat transfer characteristics, three non-dimensional variables are defined, such as the fin axial length ratio (α), width ratio (β), and height ratio (γ). The thermal enhancement factor (η) is adopted as an evaluation criterion to evaluate the best comprehensive thermal-hydraulic performance of MOPF. Results indicate that the oval-shaped pin fins in the microchannel can effectively prevent the rise of heat surface temperature along the flow direction, which improves the temperature distribution uniformity. In addition, results show that for the studied Reynolds number range and microchannel geometries in this paper, the thermal enhancement factor η increases firstly and then decreases with the increase of α and β. In addition, except for Re = 157, η decreases first and then increases with the increase of the fin height ratio γ. The thermal enhancement factor for MOPF with α = 4, β = 0.3, and γ = 0.5 achieves 1.56 at Re = 668. The results can provide a theoretical basis for the design of a microchannel heat exchanger.     

Design and synthesis of biologically active carbaglycosylamines: From glycosidase inhibitors to pharmacological chaperones

For over 50 years, our group has been involved in synthetic studies on biologically active cyclitols including carbasugars. Among a variety of compounds synthesized, this review focuses on carbaglycosylamine glycosidase inhibitors, highlighting the following: (1) the naturally occurring N-linked carbaoligosaccharide α-amylase inhibitor acarbose and related compounds; (2) the novel synthetic β-glycosidase inhibitors, 1′-epi-acarviosin and its 6-hydroxy analogue as well as β-valienaminylceramide and its 4′-epimer; (3) the discovery of the β-glycosidase inhibitors with chaperone activity, N-octyl-β-valienamine (NOV) and its 4-epimer (NOEV); and (4) the recent development of the potential pharmacological chaperone N-alkyl-conduramine F-4 derivatives.     

A group of glycosphingolipids found in an invertebrate: Their structures and biological significance

A novel group of glycosphingolipids was identified in the nervous tissue and skin of the mollusc, Aplysia kurodai, which lacks gangliosides. More than 30 glycolipids were detected on HPTLC plates and the structures of 9 major glycolipids were determined. They were pentaosylglycosphingolipids and their common core structure was GalNAcα1→3Galβ1→4Glcβ1→1ceramide, except for one glycolipid in which Galβ of the core structure was replaced by Galα. 3-O-MeGalβ or 4-O-MeGlcNAcα or 3,4-O-carboxyethylideneGalβ was at their non-reducing ends. Galα or Fucα binds to Gal of the core structure at 2C as a side chain sugar. One to three 2-aminoethylphosphonic acids and/or phosphoethanolamine link to the glycolipids. Immunohistochemically, glycolipids having carboxyethylideneGal at their non-reducing ends were localized exclusively in nerve bundles. Glycolipids activated cAMP-dependent protein kinase in the rat brain and may directly activate cAMP-dependent protein kinase in a manner similar, but not identical, to that of cAMP. The biological functions of glycolipids may share neurobiological functions proposed for gangliosides in vertebrates.     

Swimming Mode of Two Interacting Squirmers under Gravity in a Narrow Vertical Channel

The swimming mode of two interacting squirmers under gravity in a narrow vertical channel is simulated numerically using the lattice Boltzmann method (LBM) in the range of self-propelling strength 0.1 ≤ α ≤ 1.1 and swimming type −5 ≤ β ≤ 5. The results showed that there exist five typical swimming patterns for individual squirmers, i.e., steady upward rising (SUR), oscillation across the channel (OAC), oscillation near the wall (ONW), steady upward rising with small-amplitude oscillation (SURO), and vertical motion along the sidewall (VMS). The parametric space (α, β) illustrated the interactions on each pattern. In particular, the range of oscillation angle for ONW is from 19.8° to 32.4° as α varies from 0.3 to 0.7. Moreover, the swimming modes of two interacting squirmers combine the two squirmers’ independent swimming patterns. On the other hand, the pullers (β < 0) attract with each other at the initial stage, resulting in a low-pressure region between them and making the two pullers gradually move closer and finally make contact, while the result for the pushers (β > 0) is the opposite. After the squirmers’ interaction, the squirmer orientation and pressure distribution determine subsequent squirmer swimming patterns. Two pushers separate quickly, while there will be a more extended interaction period before the two pullers are entirely separated.     

Sex-related Differences in Exercise Capacity Trends and Determinants after Cardiac Rehabilitation in Patients with Acute Myocardial Infarction

Objective: This study aimed to investigate whether longitudinal changes in exercise capacity in patients with acute myocardial infarction (AMI) differ by sex and clarified what contributed to these differences. Methods: We retrospectively examined the differences in each variable between men and women in 156 patients with AMI (mean age: 65 ± 12 years; 82.0% male) who participated in a 3-month cardiac rehabilitation (CR) program and could be followed-up for exercise capacity 12-months after AMI onset. Sex-related differences in the change in peak oxygen uptake (peak VO₂) at baseline, 3-months, and 12-months after AMI were analyzed. Results: Male patients with AMI were younger and had higher body mass index and employment rate than women. The attendance of the CR program was higher in women (men vs. women; 10 [3–15] vs. 14 [11–24] sessions, p = 0.0002). Women showed a significant lower %change in peak VO₂ after 12 months (men vs. women; 7.8% [–0.49% to 14.6%] vs. 1.3% [–5.7% to 7.5%], p = 0.013). In multiple linear regression analysis, age (β = –0.76, 95% confidence interval [CI] = –1.0 to –0.50, p <0.0001) and female sex (β = –6.3, 95% CI = –9.1 to –3.5, p <0.0001) were negative independent predictors of change in peak VO₂ over 12 months, while CR attendance (β = 0.21, 95% CI = 0.0032–0.42, p = 0.047) and recommended exercise habit after the CR program (β = 2.1, 95% CI = 0.095–4.1, p = 0.040) were positive independent predictors of change in peak VO₂ over 12 months. Conclusion: In female patients, exercise capacity improved during the CR program but decreased to AMI onset levels after 12 months.     

Development of β -keto ester and malonate chemistry: Palladium-catalyzed new reactions of their allylic esters

During extensive studies on π-allylpalladium chemistry, we have developed classical β-keto ester and malonate chemistry to a new generation by discovering a variety of palladium-catalyzed reactions of their allylic esters. Palladium enolates are generated from allyl β-keto esters after decarboxylation and undergo the following transformations; a) reductive elimination to provide α-allyl ketones, b) elimination of β-hydrogen to give α, β-unsaturated ketones, c) formation of α-methylene ketones, d) hydrogenolysis to give ketones, e) aldol condensation, and f) Michael addition. Allyl malonates and cyanoacetes undergo similar reactions. Results of these studies, including several applications carried out by other researchers are summarized.     

RET receptor signaling: Function in development,metabolic disease,and cancer

The RET proto-oncogene encodes a receptor tyrosine kinase whose alterations are responsible for various human cancers and developmental disorders, including thyroid cancer, non-small cell lung cancer, multiple endocrine neoplasia type 2, and Hirschsprung’s disease. RET receptors are physiologically activated by glial cell line-derived neurotrophic factor (GDNF) family ligands that bind to the coreceptor GDNF family receptor α (GFRα). Signaling via the GDNF/GFRα1/RET ternary complex plays crucial roles in the development of the enteric nervous system, kidneys, and urinary tract, as well as in the self-renewal of spermatogonial stem cells. In addition, another ligand, growth differentiation factor-15 (GDF15), has been shown to bind to GFRα-like and activate RET, regulating body weight. GDF15 is a stress response cytokine, and its elevated serum levels affect metabolism and anorexia-cachexia syndrome. Moreover, recent development of RET-specific kinase inhibitors contributed significantly to progress in the treatment of patients with RET-altered cancer. This review focuses on the broad roles of RET in development, metabolic diseases, and cancer.     

Observation of χb production in the exclusive reaction ′→γγχb→γγ→γγ(eeorμμ−)

We report on the observation of 1 ³P_J (χ_b) production in the reaction ′→γχ_b→γγ→γγ(e⁺e⁻ or μ⁺μ⁻). The data were recorded with the nonmagnetic CUSB detector at the Cornell Electron Storage Ring, CESR. We observe 124 γγ events with either an electron or muon pair in the final state. In the γγ correlation plot about 40% of the events cluster around (120, 430) MeV.     

Advanced muon radiography with compact accelerator system

By using a well-defined mono-energetic, pencil-like, high-energy and intense muon beam, one can realize, via simultaneous measurements of energy-loss and multiple-scattering, a quick and element-selective radiography to detect e.g. a few kg of U which is shielded in a thick Fe container or hidden within 2–3 m of low-Z material. A source of such an ideal beam of muons can be realized in transportable form via truck trailers, by combining a compact 400 MeV electron accelerator for photo π/μ production, a superconducting solenoid for full-solid-angle π/μ capture and transport, a stopping in hot tungsten metal for cooling of energetic μ⁺ to sub-eV μ⁺, and finally a compact linear accelerator for rapid acceleration to 600 MeV. Principle and some details are described.