Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) microcellular foams using a melt memory effect as bubble nucleation sites

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) foams were prepared by a foam injection molding (FIM) process using nitrogen (N2) as a physical blowing agent. PHBH is a marine degradable polymer known for its heat treatment weakness. Gel permeation chromatography and rheological measurements showed that the molecular weight was reduced when the polymer was processed at a temperature higher than 160°C; however, it had a prominent melt memory of crystallization at a temperature lower than 170°C. The melt memory effect increased the crystallization temperature and provided crystal nucleation sites, which became bubble nucleation sites in the foaming process. Microcellular foams, whose cell size is smaller than 30 μm and cell density is higher than 3 × 10⁸ cells cm⁻³, were prepared using the melt memory effect while suppressing the thermal decomposition by tuning the injected polymer's temperature (melting temperature) and the core-back timing. The mechanical properties of the resulting foams were evaluated, indicating that a high ductility PHBH microcellular foam was obtained at a melting temperature of 150°C

Design of Hemispherical Radio Frequency (RF) Capacitive-type Electrode Free of Edge Effects for Treatment of Intracavitary Tumors

A new hemispherical electrode to heat oral cavity cancer is proposed. The electrode does not produce a hot spot around its edge, a feature that usually arises when using radio frequency (RF) capacitive-type heating. The hemispherical electrode was designed by computer simulation using a 3-D finite element method. To assess its practicality and effectiveness, we built a prototype hemispherical electrode and evaluated its heating characteristics by phantom experiments. The heating effects on the phantom were measured by thermography. The concave phantom surface in contact with the hemispherical electrode showed a uniform increase in temperature, with no obvious edge effect. The proposed electrode allows non-invasive RF capacitive-type heating for intracavity tumors that was not previously considered possible, and should contribute to the multidisciplinary treatment of intracavity tumors

Photoinduced 1,2-Hydro(cyanomethylation) of Alkenes with a Cyanomethylphosphonium Ylide

An efficient method has been developed for the 1, 2-hydro(cyanomethylation) of alkenes, in which a cyanomethyl radical species is generated from a cyanomethylphosphonium ylide by irradiation with visible light in the presence of an iridium complex, a thiol, and ascorbic acid. The cyanomethyl radical species then adds across the C=C double bond of an alkene to form an elongated alkyl radical species that accepts a hydrogen atom from the thiol to produce an elongated aliphatic nitrile. The ascorbic acid acts as the reductant to complete the catalytic cycle

Long-term Follow-up of Orthodontic Patient with Cervical Lymphangioma

Aim: To report a treatment case of mandibular deviation caused by congenital cervical lymphangioma with traditional orthodontic techniques, following-up by 10-year retention. Background: Lymphangiomas, developmental anomalies, can induce various disturbances of swallowing, mastication, speech, breathing, and skeletal deformities as well as psychological stress and anxiety for the patient and their family. Lymphangiomas are benign with virtually no possibility of turning into a malignant lesion, so clinical management aims to treat the patient functionally. Case description: A girl, aged 6 years and 4 months, complained about facial asymmetry and anterior crossbite caused by congenital cervical lymphangioma. Her facial profile was the straight type with an adequate lip position. Anterior and right-side posterior crossbites were observed. On the frontal cephalogram, the menton shifted 3.0 mm to the right. A functional appliance with an expander was placed to correct her dental midline deviation and posterior crossbite. After 2-year treatment, the anterior and right-side posterior crossbites were improved. Multibracket treatment began after the growth spurt. After 44-month active treatment, a functional occlusion, including a Class I molar relationship with a proper interincisal relationship, was achieved. A functional occlusion was maintained during a 10-year retention period, while a mandibular downward growth was observed through the retention period. Conclusion: Conventional orthodontic techniques enable functional and stable occlusion even in patients with mandibular deviation caused by congenital cervical lymphangioma, although only using early orthodontic management by itself may have some limitations. Clinical significance: The hybrid technique combining functional appliance and intermaxillary elastics proves to be an effective therapy for correcting occlusal cant and mandibular deviation caused by cervical lymphangioma

Various Types of HIV Mixed Infections in Cameroon

AbstractIn order to assess the incidence of HIV mixed infection as well as to clarify the molecular epidemiology of HIV in central Africa, we investigated 43 HIVs obtained from 211 Cameroonian AC, ARC, and AIDS patients in 1994 and 1995. Part of thepolregion and part of theenvregion were phylogenetically analyzed. The genotypes observed were varied: of 43 specimens, 28 (65%) were subtype A, 1 (2%) was subtype B, 2 (5%) were subtype D, 3 (7%) were subtype F, and 2 (5%) were group O. Of the remaining 7 specimens, 3 were mixed infections with HIV-1 subtypes A and C, HIV-1 subtypes C and F, and HIV-2 subtype A and HIV-1 subtype A; 1 was a mixed infection with HIV-1 subtypes A and D and the highly divergent group O (triple infection); another 3 appeared to consist of mosaic genomes (A/G, A/E, and B/A recombinant). These data show that various types of mixed infection, such as between different subtypes of HIV-1 group M, between HIV-1 and HIV-2, and even between HIV-1 groups O and M, were confirmed at a rather high frequency (approximately 10%). The mixed infection is particularly significant where there is a greater variety of HIV-1 subtypes circulating, since it results in new genetic diversity generated by intersubtype recombination

Expression of Intercellular Adhesion Molecule-1 in the Livers of Rats Treated with Diethylnitrosamine

It has been reported that levels of soluble intercellular adhesion molecule-1 (ICAM-1) in the blood are elevated in hepatocellular carcinoma patients. In the present study, serial observations of the localization of ICAM-1 in the liver were made by light and electron microscopy in rats with carcinogen-induced cancer. Male Fisher rats were given diethylnitrosamine (DEN) orally in their drinking water. Rats were sacrificed at 6, 8, 12, or 14 weeks after the start of DEN administration and the liver tissue was collected. ICAM-1 expression in liver was assessed using indirect immunoperoxidase staining with anti-rat ICAM-1 antibody. Although ICAM-1 expression by endothelial cells in livers of DEN-treated rats was lower than in the control group at 8 weeks, it was higher in the membrane and cytoplasm of hepatocytes. The expression of ICAM-1 in mesenchymal cells was decreased, paralleling development of cellular atypia, whereas in hepatocyte membranes and cytoplasm it was increased in these atypia. ICAM-1 was localized to the cytoplasm of cancer cells, but to the membrane of hepatocytes in the treated livers at 14 weeks. Furthermore, the levels of ICAM-1 in mesenchymal cells tended to be lower in the cancerous area than in the atypical hyperplastic nodule, and were reduced as the density of cell atypia increased, in comparison to cells in areas without cancerous nodules. We concluded that ICAM-1 may be influenced the development of cancer induced in the rat liver by a chemical carcinogen

Effect of pregnancy on plasma phenobarbital concentrations in rats.

We examined the pharmacokinetics of phenobarbital before and during pregnancy in rats. Animals were divided into four groups: (a) control, (b) pregnant, (c) phenobarbital-treated, and (d) phenobarbital-treated pregnant groups. The increase in body weight of nonpregnant or pregnant rats was not influenced by long-term phenobarbital treatment. Plasma phenobarbital concentrations during the period of long-term phenobarbital treatment with a fixed dosage by body weight were not significantly affected by pregnancy. Furthermore, pregnancy did not affect pharmacokinetic parameters of phenobarbital between 0.25 and 24h after administration. These results suggest that pregnancy does not influence on the pharmacokinetics of long-term phenobarbital treatment at a fixed dosage by body weight.</p

Generation of third-harmonic spin oscillation from strong spin precession induced by terahertz magnetic near fields

The ability to drive a spin system to state far from the equilibrium is indispensable for investigating spin structures of antiferromagnets and their functional nonlinearities for spintronics. While optical methods have been considered for spin excitation, terahertz (THz) pulses appear to be a more convenient means of direct spin excitation without requiring coupling between spins and orbitals or phonons. However, room-temperature responses are usually limited to small deviations from the equilibrium state because of the relatively weak THz magnetic fields in common approaches. Here, we studied the magnetization dynamics in a HoFeO3 crystal at room temperature. A custom-made spiral-shaped microstructure was used to locally generate a strong multicycle THz magnetic near field perpendicular to the crystal surface; the maximum magnetic field amplitude of about 2 T was achieved. The observed time-resolved change in the Faraday ellipticity clearly showed second- and third-order harmonics of the magnetization oscillation and an asymmetric oscillation behaviour. Not only the ferromagnetic vector M but also the antiferromagnetic vector L plays an important role in the nonlinear dynamics of spin systems far from equilibrium