This paper analyzed the energy balance of extensive green roofs and presented a simple but practical energy balance model. Field experiment justified the validation and accuracy of this model. Experimental results demonstrated that within 24 h of a typical summer day, when soil was rich in water content, solar radiation accounted for 99.1% of the total heat gain of a Sedum lineare green roof while convection made up 0.9%. Of all dissipated heat 58.4% was by the evapotranspiration of the plants-soil system, 30.9% by the net long-wave radiative exchange between the canopy and the atmosphere, and 9.5% by the net photosynthesis of plants. Only 1.2% was stored by plants and soil, or transferred into the room beneath. [All rights reserved Elsevier].

The sorption isotherm is one of the most important hygrothermal properties of porous building materials, and is usually determined by the static gravimetric test. Typically the static gravimetric test takes weeks or months to complete, thus various measures are adopted to improve the test efficiency. Unfortunately, not all these measures have been validated specifically. This paper aims at validating several widely accepted measures to speed up the static gravimetric test on autoclaved aerated concrete at 25?°C. Experimental results show that oven drying at 70?°C gives nearly identical dry mass as desiccant drying at room temperature does, but is much faster than the desiccant method and avoids potential risks at 105?°C. Moreover, large and small samples provide almost the same equilibrium moisture content, while small samples shorten test time obviously. In addition, as long as one-way adsorption process is kept without reverse, the effect of intermediate relative humidity levels on the equilibrium moisture content is negligible, supporting the method of exposing different samples to different RH levels simultaneously. Last but not least, a new mathematical model is introduced to fit the sorption curves. It works better than the Oswin, Henderson, Caurie, GAB, Hansen and Peleg models do.

Unusually among bacteria, actinobacteria possess myo-inositol 1-phosphate synthase (mIPS). In the developmentally complex Streptomyces coelicolor, the mIPS-encoding gene (inoA) is cotranscribed with a putative regulatory gene (inoR). The inoRA transcript was more abundant in an inoR in-frame deletion mutant, and InoR formed different complexes in vitro with an extensive region around the inoRA promoter. Binding was relieved by adding glucose 6-phosphate. Thus, InoR is a metabolite-sensitive autorepressor that influences inoA expression, and hence the level of inositol, by controlling transcription from PinoRA. Disruption of inoA resulted in inositol-dependent growth and development, with full phenotypic correction at 0.1 mM inositol: at lower inositol concentrations differentiation was arrested at intermediate stages. This pattern may partly reflect increased demand for membrane phospholipids during sporulation septation. A corresponding sharp upregulation of inoRA transcription coincident with sporulation was dependent on a developmental regulator, WhiI. A truncated form of WhiI could bind two sites downstream of PinoRA, and one of the WhiI-binding sites overlapped the InoR-binding site. The combined action of a metabolic regulator and a developmental regulator at the simple PinoRA promoter is a previously undescribed strategy for the differential provision of developmentally appropriate levels of a substance required during the formation of spore chains.

The magnetic properties of two-dimensional antiferromagnet NiGa2S4 have attracted much attention and yet some problems are far from being solved. We investigate the magnetic properties of NiGa2S4 by Monte Carlo simulations. A new spin-interacting model is proposed to describe the system, and the specific heat together with the doping effect of nonmagnetic impurity is studied by simulations. The double peaks of the specific heat as well as other behaviors are well reproduced. We also compare our results with those of other models, and the underlying physics is discussed.

BACKGROUND Polyoxins are potent inhibitors of chitin synthetases in fungi and insects. The gene cluster responsible for biosynthesis of polyoxins has been cloned and sequenced from Streptomyces cacaoi and tens of polyoxin analogs have been identified already. RESULTS The polyoxin biosynthetic gene cluster from Streptomyces cacaoi was heterologously expressed in the sanN inactivated mutant of Streptomyces ansochromogenes as a nikkomycin producer. Besides hybrid antibiotics (polynik A and polyoxin N) and some known polyoxins； two novel polyoxin analogs were accumulated. One of them is polyoxin P that has 5-aminohexuronic acid with N-glycosidically bound thymine as the nucleoside moiety and dehydroxyl-carbamoylpolyoxic acid as the peptidyl moiety. The other analog is polyoxin O that contains 5-aminohexuronic acid bound thymine as the nucleoside moiety； but recruits polyoximic acid as the sole peptidyl moiety. Bioassay against phytopathogenic fungi showed that polyoxin P displayed comparatively strong inhibitory activity； whereas the inhibitory activity of polyoxin O was weak under the same testing conditions. CONCLUSION Two novel polyoxin analogs (polyoxin P and O) were generated by the heterologous expression of polyoxin biosynthetic gene cluster in the sanN inactivated mutant of Streptomyces ansochromogenes. Polyoxin P showed potent antifungal activity；while the activity of polyoxin O was weak. The strategy presented here may be available for other antibiotics producers.

We study electronic spin-polarised transport in a system composed of a quantum dot (QD) connected to one normal metal electrode and one ferromagnetic one. The electrical current of each spin component and the spin accumulation on the QD are calculated by using the nonequilibrium Green's function method. We find that in the Coulomb blockade regime, the current spin polarisation can reach 100% under a strong magnetic field. Meanwhile, the spin accumulation on the QD approaches to unit, and thus the dot is occupied by electrons of one certain spin orientation. The system can operate as a spin injector from a normal metal reservoir to a semiconductor material, and may find real usage in solid state quantum information processes.

Abstract Hydroelectric power is widely used because of its environmental, renewable and green. The cavitation is inevitable phenomenon during the operation of hydroturbine which is related to the efficiency and service life of the unit. This paper is devoted to discriminate the phenomenon of the incipient cavitation, prevent the destruction early, and avoid the irreversible damage to hydroturbine. In order to find the characters of incipient cavitation. Use the method of wavelet time-frequency analysis and wavelet packet decomposition to process the cavitation noise signals. Use the value of peak factor and slope of power spectral density curve as a threshold when incipient cavitation to judge whether the cavitation occurs. The results shows that the characteristics of incipient cavitation can be detected in the auditory frequency band. The wavelet time-frequency analysis of noise signals can distinguish the different operating conditions, also can discriminate between the phenomenon of incipient cavitation and the other state of cavitation by visual observation. The wavelet packet decomposition can obtain the feature frequency of cavitation signal is 10–13 kHz. The way of judge whether the incipient cavitation happens by threshold value can reach the accuracy rate up to 70% which meet the requirements of the detection for incipient cavitation.