Chemical basis of anti-listerial effects of rosemary herb during stomaching with fresh-cut vegetables

Fresh rosemary herb has demonstrated much stronger anti-listerial effects when stomached with contaminated fresh-cut vegetables than those obtained by application of rosemary essential oils. Various types of rosemary extracts (hydrodistillates, CO₂ extracts, hexane/acetone extracts) were analysed by GC–MS and tested for anti-listerial effects in vitro. Principal component analysis showed that verbenone levels were most correlated with anti-listerial effects, followed by levels of camphor. Stomaching rosemary herb greatly increased headspace levels of verbenone and camphor (by up to 20 times) compared to intact or chopped fresh rosemary. It is speculated that by crushing the herb under water, stomaching released enhanced levels of these components as lipophilic nanosomes which rapidly migrated to lipophilic surfaces, including the membranes of Listeria cells.     

The Influence of Hydrogen Induction on The Characteristics of a CI Engine Fueled with Blend of Camphor Oil and Diesel with Diethyl Ether Additive

This article investigates the effect of hydrogen induction on the characteristics of a CI engine fueled with the blend of camphor oil and diesel, along with diethyl ether (DEE) as an additive. The fuel sample was prepared by mixing 70% camphor oil with 30% diesel (C7D3) on a volume basis and then tested with 4 LPM (C7D3H4), 6 LPM (C7D3H6), and 8 LPM (C7D3H8) of hydrogen induction on the engine intake manifold. DEE was mixed at 10% and 20% with 90% and 80% of C7D3 on a volume basis and evaluated with 8 LPM of hydrogen induction; the resulting mixtures were designated as C7D3H8E10 and C7D3H8E20. The maximum thermal efficiency for C7D3H8E10 is 32.97%, with a minimum BSEC of 10.91 MJ/kgh, CO of 5.22 g/kWh, HC of 0.206 g/kWh, and smoke opacity of 39.6%. Hydrogen induction and increasing the quantity of hydrogen from 4 lpm to 8 lpm in the manifold increases the thermal efficiency to 32.63%. Further, it reduces the BSEC to 11.03 MJ/kgh, CO of 5.65 g/kWh, HC of 0.222 g/kW, and smoke opacity of 46.3%. NO_x emissions were found to increase while increasing the hydrogen induction and with a 10% DEE addition to the C7D3 fuel. Further, raising the DEE from a 10%–20% ratio reduces the thermal efficiency and increases the BSEC, CO, HC, and smoke emissions. Overall, C7D3 in CI engines with 10% more DEE and hydrogen induction up to 8 LPM may be used efficiently.     

Light-induced changes in the solar cell parameters and temperature coefficient of n-C/p-Si heterojunction solar cell

Amorphous carbon (a-C) is a potential material for the development of low-cost and high-efficiency solar cell. We report the study of the influence of light soaking up to 100 h on n-C/p-Si heterojunction solar cell. It is observed that the deterioration in the fill factor and the efficiency are significantly smaller as compared to that observed in a-Si:H solar cell. Variations in the temperature coefficients of the I–V characteristics subjected to light degradation and recovery has also been investigated. A good correlation between change in the temperature coefficient and the degradation/recovery state of cell's conversion efficiency has been observed.     

手性樟脑磺内酰胺合成工艺的研究

樟脑磺内酰胺是一种重要的手性助剂,被广泛应用于不对称合成领域。主要探讨了以天然樟脑为原料,依次经过磺酰化、酰氯化、酰胺化、环化、还原五步反应合成出目标产物樟脑磺内酰胺的工艺。考察了反应时间、温度、试剂、催化剂等对收率的影响,最后确定了最佳反应条件,使反应的总收率有了较大的提高。     

与树有关--湖南大学工商管理大楼方案设计

本文介绍了湖南大学工商管理大楼的设计过程,针对基地环境的各种制约因素,设计者提出了以樟树激活环境、朴素的设计观、复合界面处理、低造价等设计理念,结合创作实践进行了有益的探索。     

Structure and properties of Camphor silk

Wild non-mulberry silk has long been mainly used as a textile fiber and as biomedical sutures for decades. In this study, we reported a unique wild silk variety, the Camphor silk. Compared with the Bombyx mori (B. mori) silk and Antheraea pernyi (A. pernyi) silk cocoons, the Camphor silkworm cocoon is smaller and has a thinner cocoon wall. Similar to the A. pernyi cocoon, the Camphor cocoon also has a large amount of crystals covering its outer layers. The breaking strength and tenacity of the Camphor silk with and without degumming were significantly higher than that of A. pernyi and B. mori silks. Moreover, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermo gravimetric (TG) analyses were employed to provide an insight into the superior mechanical properties of the Camphor silk. The results showed that the Camphor silk has a high degree of crystallinity and high decomposition temperature (329 °C), which contribute to its outstanding mechanical properties. This study provides a new alternative protein material for composites and biomedical devices.     

Influence of different types of acidic dopant on the electrodeposition and properties of polyaniline films

The effect of different types of acidic dopant namely, poly(vinyl sulfonic) (PVS), camphor sulfonic (CSA) and hydrochloric acids on the electrodeposition of polyaniline (PANI) films by cyclic voltammetry has been investigated and correlated with the morphology and properties of the polymers produced. The polymer films were studied by cyclic voltammetry, electron microscopy, u.v.–visible spectroscopy, X-ray diffraction and conductivity measurements. The nucleation step of the electrodeposition of PANI depends on the counter-ion of the dopant and significantly affects polymer growth as well as the morphology of the polymers produced. The properties of the polymeric films were also greatly influenced by the type of acid dopant used in the electrodeposition. Although all dopants used were protonic acids the conductivity of the polymer was affected by the counter-ion and could be enhanced by exposition to m-cresol due to secondary doping effects.     

Supercritical CO2 Extraction of Essential Oil from Algerian Rosemary (Rosmarinus officinalis L.)

The present study presents experimental results concerning the supercritical CO₂ extraction of essential oil from Algerian rosemary leaves. The effects of key operating parameters such as pressure, temperature, particle size and CO₂ mass flow rate on the extraction yield were investigated. The obtained yields were in the range of 0.95–3.52 g oil/g dry rosemary, and the best value was observed at a pressure of 22 MPa, a temperature of 40 °C, a flow rate of 7 g/min, and a particle size of 1 mm. The performance of the local rosemary used was assessed by comparison of the obtained yields with values reported in the literature for essential oils derived from different rosemary sources. The GC and the GC‐MS analyses showed that the major compound detected in the essential oil was camphor, at 48.89 wt %.     

Adsorption of camphor and 2,2′-bipyridine on Bi(1 1 1) electrode surface

Impedance spectroscopy and in situ STM methods have been used for investigation of the camphor and 2,2′-bipyridine (2,2′-BP) adsorption at the electrochemically polished Bi(1 1 1) electrode from weakly acidified Na₂SO₄ supporting electrolyte solution. The influence of electrode potential on the adsorption kinetics of camphor and 2,2′-BP on Bi(1 1 1) has been demonstrated. In the region of maximal adsorption, i.e. capacitance pit in the differential capacitance versus electrode potential curve, the heterogeneous adsorption and diffusion steps are the rate determining stages for camphor and 2,2′-BP adsorption at the Bi(1 1 1) electrode. It was found that for camphor | Bi(1 1 1) interface the stable adsorbate adlayer detectable by using the in situ STM method has been observed only at the positively charged electrode surface, where the weak co-adsorption of SO₄²⁻ anions and camphor molecules is possible. At the weakly negatively charged Bi(1 1 1) electrode surface there are only physically adsorbed camphor molecules forming the compact adsorption layer. The in situ STM data in a good agreement with impedance data indicate that a very well detectable 2,2′-BP adsorption layer is formed at Bi(1 1 1) electrode in the wide region of charge densities around the zero charge potential.     

Effect of illumination intensity and temperature on the I–V characteristics of n-C/p-Si heterojunction

Krishna et al. (Sol. Energy Mater. Sol. Cells 65 (2001) 163) have recently developed an heterojunction n-C/p-Si in order to achieve low cost and high-efficiency carbon solar cell. It has been shown that for this structure, the maximum quantum efficiency (25%) appears at wavelength λ (600 nm). In this paper, the dependence of I–V characteristics of this heterojunction solar cell on illumination intensity and temperature has been systematically investigated. An estimation of the stability of the solar cell with temperature has been made in terms of the temperature coefficient of I_sc and V_oc. The intensity variation study has been used to estimate the series resistance R_s of the solar cell.The effect of illumination intensity on I–V of n-C/p-Si heterojunction is more complex because the carrier lifetime and the carrier mobility of amorphous carbon are small and also because drift of carriers by built-in electric field plays an important role in these cells. Therefore, the conventional analytical expression for I–V characteristic is not applicable to such solar cells. These structures will not obey the principle of superposition of illuminated and dark current. The experimental results have been analysed by developing empirical relation for I–V.The temperature sensitivity parameters α, the change in I_sc and β, the change in V_oc per degree centigrade have been computed and are found to be 0.087 mA/°C and 1 mV/°C, respectively. This suggests that the heterojunction n-C/p-Si has good temperature tolerance. The value of series resistance has been estimated from the family of I–V curves at various intensities. The R_s is found to be ≈12 Ω, which is on the higher side from the point of view of photovoltaic application.