Enhanced production of poly (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer with manipulated variables and its properties

Cupriavidus sp. USMAA1020, a local isolate was able to biosynthesis poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer with various 4HB precursors as the sole carbon source. Manipulation of the culture conditions such as cell concentration, phosphate ratio and culture aeration significantly affected the synthesis of P(3HB-co-4HB) copolymer and 4HB composition. P(3HB-co-4HB) copolymer with 4HB compositions ranging from 23 to 75 mol% 4HB with various mechanical and thermal properties were successfully produced by varying the medium aeration. The physical and mechanical properties of P(3HB-co-4HB) copolymers were characterized by NMR spectroscopy, gel-permeation chromatography, tensile test, and differential scanning calorimetry. The number-average molecular weights (M (n)) of copolymers ranged from 260 x 10(3) to 590 x 10(3)Da, and the polydispersities (M (w)/M (n)) were between 1.8 and 3.0. Increases in the 4HB composition lowered the molecular weight of these copolymers. In addition, the increase in 4HB composition affected the randomness of copolymer, melting temperature (T (m)), glass transition temperature (T (g)), tensile strength, and elongation to break. Enzymatic degradation of P(3HB-co-4HB) films with an extracellular depolymerase from Ochrobactrum sp. DP5 showed that the degradation rate increased proportionally with time as the 4HB fraction increased from 17 to 50 mol% but were much lower with higher 4HB fraction. Degradation of P(3HB-co-4HB) films with lipase from Chromobacterium viscosum exhibited highest degradation rate at 75 mol% 4HB. The biocompatibility of P(3HB-co-4HB) copolymers were evaluated and these copolymers have been shown to support the growth and proliferation of fibroblast cells

Mating system, sex ratio, and persistence of females in the gynodioecious shrub Daphne laureola L. (Thymelaeaceae)

Although in gynodioecious populations male steriles require a fecundity advantage to compensate for their gametic disadvantage, southern Spanish populations of the long-lived shrub Daphne laureola do not show any fecundity advantage over hermaphrodites in terms of seed production and early seedling establishment. By using allozyme markers, we assess the mating system of this species in five populations differing in sex ratio, and infer levels of inbreeding depression over the whole life cycle by comparing the inbreeding coefficients at the seed and adult plant stages. Extremely low outcrossing rates (0.001oto0.125) were consistently found for hermaphrodites in all populations, whereas, as expected, female progeny were entirely outcrossed. In most populations, offspring were much more inbred than their parents, and heterozygosity of adults was greater than expected from outcrossing rate estimates, with very few selfed progeny appearing to reproduce in the field. The combination of extensive selfing in hermaphrodites and a strong inbreeding depression expressed late in the life cycle (and thus, only estimable by indirect measures based on genetic markers) may explain the persistence and high frequency of D. laureola females in southern Spanish populations.Peer reviewe

Properties Of Epoxy/Silica Thin Film Composite For Electronic Application.

In line with the miniaturization trends of the product designs in electronic industry, conventional packaging technology has been replaced

Transactivation by expression of the hepatitis B virus X protein with an inducible system

[[abstract]]We describe here the conditional expression of the hepatitis B virus X protein using the inducible system controlled by a tet-responsive promoter. Induction of the X protein in Rat-2 fibroblasts activated transcription from a heterologous gene promoter and stimulated the DNA-binding activity of NFkB. The ability to produce this biologically active X protein in a stable cell line will accelerate the elucidation of the function and mechanisms of X and eventually help us understand the role of X in natural viral infection and carcinogenesis

A concurrent dual-band CMOS low noise amplifier at 2.4/5.2 GHz for WLAN applications

This paper presents a concurrent dual-band CMOS low noise amplifier (LNA) at operating frequency of 2.4 GHz and 5.2 GHz for WLAN applications. The proposed LNA employed cascode common source to obtain high gain using 0.13-µm CMOS technology. The concurrent dual-band frequencies are matched using LC network band-pass and band-stop notch filter at the input and output stages. The filters help to shape the frequency response of the proposed LNA. The simulation results indicate that the LNA achieves a forward gain of 21.8 dB and 14.22 dB, input return loss of -18 dB and -14 dB at 2.4 GHz and 5.2 GHz, respectively. The noise figure of 4.1 dB and 3.5 dB with the input third-order intercept points 7 dBm and 10 dBm are obtained at 2.4 GHz and 5.2 GHz, respectively. The LNA dissipates 2.4 mW power at 1.2 V supply voltage with a chip size of 1.69 mm2

ASSESSING TOURIST SATISFACTION WITH THE FACILITIES PROVIDED AT LANGKAWI ISLAND GATEWAY JETTY TERMINALS

Kako bi povećala privlačnost i razinu zadovoljstva na turističkim destinacijama, vlada je osigurala brojne popratne sadržaje. Ti su popratni sadržaji smješteni na raznim lokacijama, uključujući lučke terminale koji imaju funkciju polazišta za turističke destinacije, posebno one smještene na otocima. Glavni cilj ove studije je ocjena razine zadovoljstva turista pruženim sadržajima na lučkim terminalima. Kako bi se taj cilj postigao, provedeno je istraživanje na 3 odabrana lučka terminala za otočje Langkawi. Kako bi se došlo do potrebnih podataka provedena je anketa gdje su turistima koji su posjetili otočje Langkawi podijeljeni upitnici. Zatim je 437 upitnika podvrgnuto metodi statističke analize. Rezultati pokazuju da je ukupna razina zadovoljstva turista pruženim sadržajima na lučkim terminalima niža od zadovoljavajuće. Ova je studija također pokazala da razina zadovoljstva kod turista ne utječe na njihovu odluku da ponovno posjete otočje Langkawi, ali utječe na njihovu odluku o odabiru alternativnih polazišta pri njegovoj posjeti

ASSESSING TOURIST SATISFACTION WITH THE FACILITIES PROVIDED AT LANGKAWI ISLAND GATEWAY JETTY TERMINALS

Kako bi povećala privlačnost i razinu zadovoljstva na turističkim destinacijama, vlada je osigurala brojne popratne sadržaje. Ti su popratni sadržaji smješteni na raznim lokacijama, uključujući lučke terminale koji imaju funkciju polazišta za turističke destinacije, posebno one smještene na otocima. Glavni cilj ove studije je ocjena razine zadovoljstva turista pruženim sadržajima na lučkim terminalima. Kako bi se taj cilj postigao, provedeno je istraživanje na 3 odabrana lučka terminala za otočje Langkawi. Kako bi se došlo do potrebnih podataka provedena je anketa gdje su turistima koji su posjetili otočje Langkawi podijeljeni upitnici. Zatim je 437 upitnika podvrgnuto metodi statističke analize. Rezultati pokazuju da je ukupna razina zadovoljstva turista pruženim sadržajima na lučkim terminalima niža od zadovoljavajuće. Ova je studija također pokazala da razina zadovoljstva kod turista ne utječe na njihovu odluku da ponovno posjete otočje Langkawi, ali utječe na njihovu odluku o odabiru alternativnih polazišta pri njegovoj posjeti

Pull-Out Resistance of Sand-Geosynthetics Reinforcement

Geosynthetics are widely used in earth retaining structures such as steep slope and earth retaining wall. The stability of the earth retaining structures depends on the interaction between geosynthetics and soil at the reinforced area known as reinforcement mechanism. The reinforcement mechanism of the soil reinforced structure usually difficult to be analysed thoroughly. It is because the preliminary study on the pull-out resistance and durability of the reinforcement material is not taking into account before it has been used to the site location especially in Malaysian practises. Less supervision and the assessment after the installation of the reinforcement materials also contributed to the failure of the soil reinforcement. In this paper, the laboratory model was used to imply the real condition of the soil reinforced structure using pull-out test. A standard pull-out test was carried out by using geotextile and geogrid reinforcing elements embedded into silica sand of size D50=1.357 mm and D50=0.571 mm subjected to normal pressures of 100 kPa, 150 kPa and 200 kPa. Comparative result and analysis showed that the geotextile reinforcement give more resistance rather than geogrid reinforcement under high normal pressure