野性的畅想 Cavalli迪拜俱乐部

<正>Italo Rota,1953年出生在米兰,是近年来活跃在意大利建筑与室内设计领域的中坚设计师。他从学生时代起就对设计表现出极高的热情,曾经在多位知名设计师麾下工作过,并且对出版业、杂志、展览,以及建筑项目都有所涉及。早在上个世纪     

Determination of Lutein from Fruit and Vegetables Through an Alkaline Hydrolysis Extraction Method and HPLC Analysis

A simple and rapid analytical method for the determination of lutein content, successfully used for cereal matrices, was evaluated in fruit and vegetables. The method involved the determination of lutein after an alkaline hydrolysis of the sample matrix, followed by extraction with solvents and analysis by normal phase HPLC. The optimized method was simple, precise, and accurate and it was characterized by few steps that could prevent loss of lutein and its degradation. The optimized method was used to evaluate the lutein amounts in several fruit and vegetables. Rich sources of lutein were confirmed to be green vegetables such as parsley, spinach, chicory, chard, broccoli, courgette, and peas, even if in a range of variability. Taking into account the suggested reference values these vegetables can be stated as good sources of lutein.     

Ionic‐Liquid Gating of InAs Nanowire‐Based Field‐Effect Transistors

Here, the operation of a field‐effect transistor based on a single InAs nanowire gated by an ionic liquid is reported. Liquid gating yields very efficient carrier modulation with a transconductance value 30 times larger than standard back gating with the SiO₂/Si₊₊ substrate. Thanks to this wide modulation, the controlled evolution from semiconductor to metallic‐like behavior in the nanowire is shown. This work provides the first systematic study of ionic‐liquid gating in electronic devices based on individual III–V semiconductor nanowires: this architecture opens the way to a wide range of fundamental and applied studies from the phase transitions to bioelectronics.     

The Effect of Electrospun Gelatin Fibers Alignment on Schwann Cell and Axon Behavior and Organization in the Perspective of Artificial Nerve Design

Electrospun fibrous substrates mimicking extracellular matrices can be prepared by electrospinning, yielding aligned fibrous matrices as internal fillers to manufacture artificial nerves. Gelatin aligned nano-fibers were prepared by electrospinning after tuning the collector rotation speed. The effect of alignment on cell adhesion and proliferation was tested in vitro using primary cultures, the Schwann cell line, RT4-D6P2T, and the sensory neuron-like cell line, 50B11. Cell adhesion and proliferation were assessed by quantifying at several time-points. Aligned nano-fibers reduced adhesion and proliferation rate compared with random fibers. Schwann cell morphology and organization were investigated by immunostaining of the cytoskeleton. Cells were elongated with their longitudinal body parallel to the aligned fibers. B5011 neuron-like cells were aligned and had parallel axon growth when cultured on the aligned gelatin fibers. The data show that the alignment of electrospun gelatin fibers can modulate Schwann cells and axon organization in vitro, suggesting that this substrate shows promise as an internal filler for the design of artificial nerves for peripheral nerve reconstruction.     

Beitrag zur Wachstumskinetik der interkristallinen Korrosion von ausgehärteten Al-Cu-Legierungen – Teil I: Ergebnisse der Folien-Durchbruchsmethode

Contribution to the growth kinetics of the intergranular corrosion of age-hardened Al-Cu alloys – Part I: Results of the foil penetration technique The growth kinetics of the intergranular corrosion (IC) of age-hardened Al-Cu-alloys in aqueous chloride solutions under potentiostatic conditions have been investigated using the foil penetration technique originally developed for pit growth measurements. The two tested systems were a pure binary Al-4% Cu-alloy (sheet thicknesses 0.2 and 0.5 mm) in 0.01 m NaCl, pH 11, and a commercial AA 2024 type alloy (various sheet thicknesses ranging from 0.2 to 1.0 mm) in 0.1 m NaCl, pH 7, respectively. Both alloys were tempered to maximum IC susceptibility and have been tested at potentials where selective anodic dissolution of the grain boundary regions occurs. As a reference system, the pit growth kinetics in commercial pure aluminum (sheet thicknesses ranging from 0.2 to 1.0 mm) in 0.01 m NaCl + 0.01 m Na₂SO₄ (as pit initiation inhibitor), pH 11, have been investigated at an applied potential considerably higher than the pitting potential. The experimental results have shown that, for the IC in the finegrained commercial alloy, a uniform growth kinetic valid for the whole range of sheet thicknesses, as for the case of pitting, cannot be formulated. The correlation of the current-time-curves and the attack morphologies (after penetration) for different sheet thicknesses with the penetration times leads to the conclusion that the growth kinetics of intergranular attacks are related to the number of sites of active attack (cracks) per metal volume. This specific number of actively growing cracks depends on the grain size and on the electrochemical conditions and, for given parameters, on the exposure time and therefore on the sheet thickness. For the commercial alloy examined, the following three stages of attack with decreasing penetration velocity of the IC could be distinguished:

• activation stage
• transition stage
• stable, macroscopic grain boundary dissolution.

The coarse-grained pure binary alloy showed a markedly higher penetration velocity of the IC under milder electrochemical conditions. This alloy is suitable for a model investigation of the first stage of attack but no quantitative kinetic information could be obtained from the only two disposable sheet thicknesses. The pit growth measurements in pure aluminum showed that the square root-of-time growth law previously found for thin foils and sheets is valid for deep pits too. The discussion explains that the electrochemical mechanisms of pitting of aluminum and of the IC in Al-Cu-based alloys are identical and that the basic difference lies in the geometry of the sites of attack. The ohmic control of the aluminum dissolution and therefore of the growth kinetics of pits and intergranular cracks is governed by the total anodic area and its different time dependence during the growth of the sites of local attack.     

Tobramycin Supplemented Small-Diameter Vascular Grafts for Local Antibiotic Delivery: A Preliminary Formulation Study

Peripheral artery occlusive disease is an emerging cardiovascular disease characterized by the blockage of blood vessels in the limbs and is associated with dysfunction, gangrene, amputation, and a high mortality risk. Possible treatments involve by-pass surgery using autologous vessel grafts, because of the lack of suitable synthetic small-diameter vascular prosthesis. One to five percent of patients experience vascular graft infection, with a high risk of haemorrhage, spreading of the infection, amputation and even death. In this work, an infection-proof vascular graft prototype was designed and manufactured by electrospinning 12.5% w/v poly-L-lactic-co-glycolic acid solution in 75% v/v dichloromethane, 23.8% v/v dimethylformamide and 1.2% v/v water, loaded with 0.2% w/w_PLGA. Polymer and tobramycin concentrations were selected after viscosity and surface tension and after HPLC-UV encapsulation efficiency (EE%) evaluation, respectively. The final drug-loaded prototype had an EE% of 95.58% ± 3.14%, with smooth fibres in the nanometer range and good porosity; graft wall thickness was 291 ± 20.82 μm and its internal diameter was 2.61 ± 0.05 mm. The graft’s antimicrobic activity evaluation through time-kill assays demonstrated a significant and strong antibacterial activity over 5 days against Staphylococcus aureus and Escherichia coli. An indirect cell viability assay on Normal Human Dermal Fibroblasts (NHDF) confirmed the cytocompatibility of the grafts.     

PCBs and selected organochlorine compounds in Italian mountain air: the influence of altitude and forest ecosystem type

Passive air samplers (polyurethane foam disks) were deployed on an altitudinal transect in the rural Italian Alps to investigate the potential influence of forest cover on air concentrations. Samplers were exposed overtwo periods, each of several weeks, either in clearings or in forests. In the first period, there was high leaf coverage (high leaf area index, LAI); in the second, the LAI was low after the autumnal leaf fall. PCBs sequestered in the PUF generally declined with altitude, for example, in the clearings PCBs-28, 52, 90/101, 118, and 138, all showed statistically significant declines (p < 0.05). The mass of HCB sequestered increased with altitude, evidence of cold condensation. Ratios of the forest:clearing concentrations were calculated; this ratio expresses the filtering ability of forests to deplete air concentrations compared to the adjacent clearings. During the high LAI sampling period, these depletion factors ranged between 0.93 and 0.54 and were inversely correlated with temperature-corrected log K0A. This relationship was notobserved during the low LAI sampling period. The depletion factors were normalized using the LAI to give a density independent depletion factor (DIDF). The slopes of the correlations with K0A were comparable for broadleaf or coniferous forests at different altitudes, suggesting that leaf surfaces determine the exchanges with air. Broadleaf forests at 1000 and 1400 m showed similar behavior, while a conifer forest at 1800 m gave depletion factors which were higher by about a factor of 2. It is suggested that DIDF can be used in regional environmental fate models to estimate the contribution of forests to contaminant fate.     

Stratigraphic analysis of intercalated graphite electrodes in aqueous inorganic acid solutions

A detailed stratigraphic investigation of the intercalation mechanism when graphite electrodes are immersed inside diluted perchloric(HClO₄)and sulfuric(H₂SO₄)electrolytes is obtained by comparing results when graphite crystals are simply immersed in the same acid solutions.By combining time-of-flight secondary ion mass spectrometry(ToF-SIMS)and in-situ atomic force microscopy(AFM),we provide a picture of the chemical species involved in the intercalation reaction.The depth intensity profile of the ion signals along the electrode crystal clearly shows a more complex mechanism for the intercalation process,where the local morphology of the basal plane plays a crucial role.Solvated anions are mostly located within the first tens of nanometers of graphite,but electrolytes also diffuse inside the buried layers for hundreds of nanometers,the latter process is also aided by the presence of mesoscopic crystal defects.Residual material from the electrolyte solution was found localized in well-defined circular spots,which represent preferential interaction areas.Interestingly,blister-like micro-structures similar to those observed on the highly oriented pyrolytic graphite(HOPG)surface were found in the buried layers,confirming the equivalence of the chemical condition on the graphite surface and in the underneath layers.     

Bijective Linear Time Coding and Decoding for k-Trees

The problem of coding labeled trees has been widely studied in the literature and several bijective codes that realize associations between labeled trees and sequences of labels have been presented. k-trees are one of the most natural and interesting generalizations of trees and there is considerable interest in developing efficient tools to manipulate this class of graphs, since many NP-Complete problems have been shown to be polynomially solvable on k-trees and partial k-trees. In 1970 Rényi and Rényi generalized the Prüfer code, the first bijective code for trees, to a subset of labeled k-trees. Subsequently, non redundant codes that realize bijection between k-trees (or Rényi k-trees) and a well defined set of strings were produced. In this paper we introduce a new bijective code for labeled k-trees which, to the best of our knowledge, produces the first coding and decoding algorithms running in linear time with respect to the size of the k-tree.     

Experimental‐numerical research on the seismic performance of URM buildings made of lightweight AAC blocks / Experimentell‐numerische Untersuchung zum seismischen Verhalten von unbewehrten Mauerwerksgebäuden aus Porenbetonblöcken

Masonry walls constructed with lightweight AAC blocks and thin‐layer mortar meet the increasingly strict requirements of energy efficiency and sustainability. In this sense, they represent an excellent solution for modern buildings, not only for external cladding but also as loadbearing elements. Despite the possible advantages of using lightweight AAC masonry, a specific assessment of its seismic performance is mandatory in order to set design recommendations allowing to reach safety levels consistent with those required for other masonry types complying with EN 1998 standard requirements. A comprehensive study on the seismic performance of unreinforced masonry buildings made of lightweight AAC was carried out in an integrated experimental‐numerical approach. The experimental campaign provided the necessary information to setup a reliable numerical model to be extensively used to assess the seismic performance of a number of prototype AAC masonry buildings with different characteristics, by means of both linear and nonlinear static (pushover) analysis. The results of this systematic numerical assessment were eventually used to draft design recommendations, to set parameters (behaviour factors) to be used in linear analysis and to calibrate rules for simple buildings.