M9住宅一期

建筑师:Sid Lee建筑事务所+Aedifica项目地点:加拿大,魁北克建筑面积:789M.C.摄影:Stephane Brugger Architects:Sid Lee Architecture+Aedifica Location:Montreal,Quebec,Canada Gross Floor Area:789M.C.Photos:Stéphane Brügger     

Laser offset-frequency locking up to 20 GHz using a low-frequency electrical filter technique

A simple, easy-to-implement, and robust technique is reported to offset lock two semiconductor lasers with a frequency difference easily adjustable up to a couple of tens of gigahertz (10 and 19 GHz experimentally demonstrated). The proposed scheme essentially makes use of low-frequency control electronics and may be implemented with any type of single mode semiconductor laser, without any requirement for the laser linewidth. The technique is shown to be very similar to the wavelength modulation spectroscopy method commonly used for laser stabilization onto molecular absorption lines, as demonstrated by experimental results obtained using 935 nm laser diodes.     

Surface properties and cell adhesion onto allylamine-plasma and amine-plasma coated glass coverslips

Surface properties of nanoparticles to be used for radioimmunotherapy need to be optimized to allow antibody conjugation while ensuring biocompatibility. We aimed to investigate cell adhesion and proliferation onto different coatings to be used for nanoparticles. C, CH _x or SiO _x coatings deposited onto glass coverslips by magnetron deposition as well as nitrogen functionalized materials synthetized using different reactive sputtering conditions and PPAA (plasma polymerized allylamine) coating, were compared. Amine functionalization did increase hydrophilicity in all the materials tested. Biocompatibility was assessed by measuring cell viability, morphology, attachment, spreading, and pro-inflammatory cytokine secretion. The results show that C and CN _x were the most biocompatible substrates while SiO _x and SiO _x N _y were the most toxic materials. PPAA coatings displayed unexpectedly an intermediate biocompatibility. A correlation could be observed between wettability and cell proliferation except for C coated surface, indicating that more complex processes than hydrophilicity alone are taking place that affect cell functions.     

A latent class model of residential choice behaviour and ethnic segregation preferences

The nature of ethnic residential clustering involves diverse population segments which through their location decisions influence the spatial patterns of ethnic settlements. While residential location is in part determined by outside constraints, choice plays a role too, making the study of preferences an important research topic. Along with differences in socio-economic characteristics, literature often emphasizes the role of unobserved (behavioural) elements in the formation of preferences for ethnic neighbourhood composition. This paper tests the potential of latent class choice models to examine both observed and unobserved heterogeneity in residential choices across ethnic groups. The empirical example is estimated on stated preferences data from Lugano, Switzerland. The results indicate different ethnic attributes as key choice drivers for households belonging to three latent classes, where the origin of households is the best predictor of class membership. Swiss citizens are mainly concerned about high shares of foreigners, advantaged foreigners favour their co-nationals, while disadvantaged foreigners hold both of such preferences.     

Fiberboards Based on Sugarcane Bagasse Lignin and Fibers

Summary: Fiberboards were prepared using phenolic type resins (phenol‐formaldehyde) and sugarcane bagasse fibers. Lignin extracted through an organosolv process from sugarcane bagasse was used as substitute of phenol in phenolic resins from 40 (lignin‐phenol‐formaldehyde) to 100 wt.‐% (lignin‐formaldehyde) substitution. Some of the fibers were chemically modified by oxidation with chlorine dioxide and treatment with furfuryl alcohol (FA), leading to fibers coated with polyfurfuryl alcohol. Thermal analysis (DSC and TGA) of the prepolymers allowed setting up an efficient curing to prepare fiberboards. Impact strength and water absorption were measured showing the importance of the curing pressure to obtain good performance. When chemically modified fibers were used to prepare board samples, enhanced durability against white root fungi is observed, and to a less degree against brown root fungi. Sugarcane bagasse fiberboards were prepared from prepolymers where lignin substituted phenol up to 100%. This replaces these materials in advantageous position, relating to those prepared from phenol‐formaldehyde resins, due to their high content of renewable raw materials. The results obtained are promising for the utilization of sugarcane bagasse as raw materials for preparing fiberboards to be used in tropical areas.

Stabilization of sugarcane bagasse fiberboards made with unmodified and modified (ClO₂ + furfuryl alcohol) fibers and phenolic resin after 8 weeks exposure against fungi.     

Aerobic spore-forming bacteria for assessing quality of drinking water produced from surface water

Cryptosporidium and Giardia represent a major microbiological issue for drinking water production from surface water. As their monitoring through a treatment process is rather tedious and as low-concentration goals should be reached for drinking water, aerobic spore-forming bacteria (ASFB) have been studied as an indicator microorganism for a drinking water treatment plant using surface water. The results reveal that monitoring naturally occurring ASFB better highlights daily achievable performances and identifies unusual process events for global disinfection, for both physical and chemical treatment steps in a multi-barrier drinking water treatment plant. Advantages of ASFB over usual process parameters are that these microorganisms are more sensitive to process fluctuations.

The use of ASFB also showed that the efficiency of ozone disinfection is not as significantly influenced by the water temperature as reported, despite similar or higher CT values applied during warmer periods. Thus, the disinfection of resistant microorganisms with ozone can also be an efficient process at lower water temperature.

ASFB have been shown to be a conservative indicator for Cryptosporidium and Giardia up to a 1st stage filtration and the ASFB Log removals can be used to estimate Log removals for Cryptosporidium and Giardia: compared to ASFB, the Log removals for Cryptosporidium or Giardia are at least equal or 50% higher, respectively. Thus, the monitoring of ASFB along a drinking water treatment process could be a useful tool for performing risk analysis for parasites such as Cryptosporidium and Giardia, and would further allow integration of daily variability into a risk analysis.     

Ion-exchange membranes made of semi-interpenetrating polymer networks,used for pervaporation-assisted esterification and ion transport

Ionic membranes were prepared by blending poly(vinyl alcohol) (PVA) with an ionic polymer. Semi-interpenetrating polymer networks (sIPN) in which the crosslinked PVA chains trap the ionic polymer were obtained by using a heat treatment at 180 °C or dibromoethane vapor at 140 °C, respectively, for poly (styrene sulfonic acid) (PSSH), poly (sodium styrene sulfonate) (PSSNa), poly (acrylic acid) (PAA) or poly (dimethyl dimethylene piperidinum chloride) (PDMeDMPCl) as the ionic polymer. The stability of the sIPN membranes in some liquid media was studied to select the appropriate membranes for the envisaged applications. The thermally crosslinked PVA/PSSH membranes showed an effective catalytic effect on the esterification reaction between n-propanol and propanoic acid. An active composite membrane made of a layer of PVA/PSSH deposited on a dense PVA layer of an industrial dehydration membrane exhibited both high catalytic activity and high selectivity to water in the pervaporation-assisted esterification. The values of the counter-ion transport number indicated that some crosslinked ionic membranes have good ion permselectivity.     

Molecular formula analysis by an MS/MS/MS technique to expedite dereplication of natural products

A facile and sensitive mass spectrometric method has been developed for the dereplication of natural products. The method provides information about the molecular formula and substructure of a precursor molecule and its fragments, which are invaluable aids in dereplication of natural products at their early stages of purification and characterization. Collision-induced MS/MS technique is used to fragment a precursor ion into several product ions, and individual product ions are selected and subjected to collision-induced MS/MS/MS analysis. This method enables the identification of the fragmentation pathway of a precursor molecule from its first-generation fragments (MS/MS), through to the nth generation product ions (MSn). It also allows for the identification of the corresponding neutral products released (neutral losses). Elements used in the molecular formula analysis include C, H, N, O, and S, as most natural products are constituted by these five elements. High-resolution mass separation and accurate mass measurements afforded the unique identification of molecular formula of small neutral products. Through sequential add-up of the molecular formulas of the small neutral products, the molecular formula of the precursor ion and its productions were uniquely determined. The molecular formula of the precursor molecule was then reversely used to identify or confirm the molecular formula of the neutral products and that of the productions. The molecular formula of the neutral fragments allowed for the identification of substructures, leading to a rapid and efficient characterization of precursor natural product. The method was applied to paclitaxel (C47H51NO14; 853 amu) to identify its molecular formula and its substructures, and to characterize its potential fragmentation pathways. The method was further validated by correctly identifying the molecular formula of minocycline (C23H27N3O7; 457 amu) and piperacillin (C23H27N5O7S; 517 amu).