数码与财富

21世纪的今天,中国人口中最流行的一句话莫过于“你不理财,财不理你”,新一轮的理财之风悠然而起。小时候,我们关注四季的变化,身边人物的变化。如今,大家更关心的是如何创造财富。成功学告诉我们,要追逐趋势,并要追逐大趋势。二十一世纪进入了数字时代,数码产品将成为主流。数码产业会给人们带来一个巨大的财富空间。     

阳光灿烂的日子——明基网通事业群总经理姚洪州专访

大码:一般来讲,相对高端的品牌都不会走电视购物的路线,明基手机为什么选择电视购物这个销售渠道？今后还有多少手机会走这个渠道？姚洪州总经理(以下简称姚总):首先我纠正一下你的话,其实不是相对高端,应该是相对有知名度的品牌一般不会走电视购物的,明基手机现在用电视或电子媒体是希望在短时间内达到一定的曝光率,实际上是     

Liquid chromatography combined with tandem mass spectrometry for the confirmation of sarafloxacin in catfish tissue

A specific chromatographic LC/MS/MS assay is described for the confirmatory identification of residues of sarafloxacin, an arylfluoroquinolone antibacterial agent, in catfish tissue. This confirmatory method takes advantage of the specificity provided by sample preparation, liquid chromatography, and tandem mass spectrometry. This kind of multidimensional analysis is commonly used in environmental, pharmacokinetic, residue, and other studies. However, we demonstrate the addition of a previously unreported criterion, the use of ion ratio ranges from the tandem mass spectrometry (MS/MS) experiment as an aid in confirmation. Using the described method, we were able to achieve MS/MS product ion ratios with <7% variation during 1 day of analysis for over 25 injections. We believe the addition of this criterion will increase the scientific certainty of the confirmatory method.     

Desired concentration-dependent ion exchange for micro-optic lenses

The required concentration-dependent diffusion coefficients for both ideal one-dimensional and ideal radial gradient-index profiles are determined. The modified quasi-chemical diffusion model is used to relate the diffusion coefficient to optimum glass composition. Adding aluminum to sodium silicate glasses facilitates the approach to the desired concentration dependence of the diffusion coefficient for silver-sodium ion exchange. A parabolic one-dimensional index profile is fabricated in one of the glasses. It deviates from ideal values by less than 2%.     

An autocorrelation-based time domain analysis technique for monitoring perfusion and oxygenation in transplanted organs

In designing an implantable sensor for perfusion monitoring of transplant organs the ability of the sensor to gather perfusion information with limited power consumption and in near real time is paramount. The following work was performed to provide a processing method that is able to predict perfusion and oxygenation change within the blood flowing through a transplanted organ. For this application, an autocorrelation-based algorithm was used to reduce the acquisition time required for fast Fourier transform (FFT) analysis while retaining the accuracy inherent to FFT analysis. In order to provide data proving that the developed method is able to predict perfusion as accurately as FFT two experiments were developed isolating both periodic and quasi-periodic cardiac frequencies. It was shown that the autocorrelation-based method was able to perform comparably with FFT (limited to a sampling frequency of 300 Hz) and maintain accuracy down to acquisition times as low as 4 s in length.     

Linking phosphorus sequestration to carbon humification in wetland soils by 31P and 13C NMR spectroscopy

Phosphorus sequestration in wetland soils is a prerequisite for long-term maintenance of water quality in downstream aquatic systems, but can be compromised if phosphorus is released following changes in nutrient status or hydrological regimen. The association of phosphorus with relatively refractory natural organic matter (e.g., humic substances) might protect soil phosphorus from such changes. Here we used hydrofluoric acid (HF) pretreatment to remove phosphorus associated with metals or anionic sorption sites, allowing us to isolate a pool of phosphorus associated with the soil organic fraction. Solution (31)P and solid state (13)C NMR spectra for wetland soils were acquired before and after hydrofluoric acid pretreatment to assess quantitatively and qualitatively the changes in phosphorus and carbon functional groups. Organic phosphorus was largely unaffected by HF treatment in soils dominated by refractory alkyl and aromatic carbon groups, indicating association of organic phosphorus with stable, humified soil organic matter. Conversely, a considerable decrease in organic phosphorus following HF pretreatment was detected in soils where O-alkyl groups represented the major fraction of the soil carbon. These correlations suggest that HF treatment can be used as a method to distinguish phosphorus fractions that are bound to the inorganic soil components from those fractions that are stabilized by incorporation into soil organic matter.     

ABC transporters Cdr1p, Cdr2p and Cdr3p of a human pathogen Candida albicans are general phospholipid translocators

We have used fluorescent 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-tagged phospholipid analogues, NBD-PE (phosphatidylethanolamine), NBD-PC (phosphatidylcholine) and NBD-PS (phosphatidylserine), to demonstrate that Cdr1p and its other homologues, Cdr2p and Cdr3p, belonging to the ATP-binding cassette (ABC) superfamily behave as general phospholipid translocators. Interestingly, CDR1 and CDR2, whose overexpression leads to azole resistance in C. albicans, elicit in-to-out transbilayer phospholipid movement, while CDR3, which is not involved in drug resistance, carries out-to-in translocation of phospholipids between the two monolayers of plasma membrane. Cdr1p, Cdr2p and Cdr3p could be further distinguished on the basis of their sensitivities to different inhibitors. For example, the in-to-out activity associated with Cdr1p and Cdr2p is energy-dependent and sensitive to sulphydryl blocking agents such as N-ethylmaleimide (NEM) and cytoskeleton disrupting agent cytochalasin E, while Cdr3p-associated out-to-in activity is energy-dependent but insensitive to NEM and cytochalasin E. We found that certain drugs, such as fluconazole, cycloheximide and miconazole, to which Cdr1p confers resistance could also affect in-to-out transbilayer movement of NBD-PE, while the same drugs had no effect on Cdr3p-mediated out-to-in translocation of NBD-PE. The ineffectiveness of these drugs to affect Cdr3p mediated out-to-in phospholipid translocation further confirms the inherent difference in the directionality of phospholipid translocation between these pumps. Notwithstanding the role of some of the Cdrps in drug resistance, this study clearly demonstrates that these ABC transporters of C. albicans are phospholipid translocators and this function could represent one of the physiological functions of such large family of proteins.     

Reduced insulin-like growth factor-I after acute feed restriction in lactating dairy cows is independent of changes in growth hormone receptor 1A mRNA

Growth hormone receptor (GHR) and insulin-like growth factor-I (IGF-I) mRNA decrease in the liver of dairy cows at parturition. Epinephrine is released and feed intake is decreased at the same time. The objective of this study was to determine whether feed restriction and (or) administration of epinephrine could recapitulate the changes in the hepatic GHR 1A and IGF-I mRNA that occur at parturition. Eight lactating cows were randomly assigned to one of two rations (ad libitum or restricted). The cows assigned to the restricted ration were fed 75, 60, 60, and 25% of feed consumed by the ad libitum cows on successive days to mimic the changes in feed intake around parturition. Liver samples were collected by needle biopsy before and after feed restriction. Cows received either 0.02 mg/kg of epinephrine or saline approximately 24 h before the second liver biopsy so that a 2 x 2 factorial arrangement of treatments was created. Feed restriction increased plasma nonesterified fatty acids and liver triglyceride percentages and decreased plasma IGF-I concentrations. The decrease in plasma IGF-I after feed restriction was associated with a decrease in IGF-I mRNA in feed-restricted cows. The amount of GHR 1A mRNA did not change after feed restriction. Epinephrine treatment did not affect the amount of GHR 1A or IGF-I mRNA. We conclude that the decrease in feed intake at parturition may be partially responsible for the decrease in IGF-I but may not cause the decrease in GHR 1A.     

Thermal process validation for Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes in ground turkey and beef products

At 55 to 70 degrees C, thermal inactivation D-values for Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes were 19.05 to 0.038, 43.10 to 0.096, and 33.11 to 0.12 min, respectively, in ground turkey and 21.55 to 0.055, 37.04 to 0.066, and 36.90 to 0.063 min, respectively, in ground beef. The z-values were 5.73, 5.54, and 6.13 degrees C, respectively, in ground turkey and 5.43, 5.74, and 6.01 degrees C, respectively, in ground beef. In both ground turkey and beef, significant (P < 0.05) differences were found in the D-values between E. coli O157:H7 and Salmonella or between E. coli O157:H7 and L. monocytogenes. At 65 to 70 degrees C, D-values for E. coli O157:H7, Salmonella, and L. monocytogenes were also significantly (P < 0.05) different between turkey and beef. The obtained D- and z-values were used in predicting process lethality of the pathogens in ground turkey and beef patties cooked in an air impingement oven and confirmed by inoculation studies for a 7-log (CFU/g) reduction of E. coli O157:H7, Salmonella, and L. monocytogenes.     

Atmospheric semivolatile organochlorine compounds in European high-mountain areas (central Pyrenees and high Tatras)

Atmospheric samples from two European high-mountain areas showed similar composition of semivolatile organochlorine compounds (SOC), such as polychlorobiphenyls (PCBs), DDTs, endosulfans, hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCHs). Nearly all compounds were predominantly found in the gas phase and only the less volatile such as some PCBs (e.g., 149, 118, 153, 138, and 180) were found in higher abundance in the particulate phase. HCB, 49-85 pg m(-3), is the dominant SOC. This compound is only found in the gas phase exhibiting uniform concentrations irrespective of season and air mass origin. SOC of present use, like HCHs and endosulfans, were found in higher concentrations in the warm periods, 32-46 and 4-10 pg m(-3) in the gas + particulate phases, respectively, reflecting their seasonal pattern of use in many European countries. PCB and 4,4'-DDE, 39-42 and 4-6 pg m(-3) in the gas + particulate phases, respectively, also showed a seasonal trend despite neither the former nor the precursor of the latter (4,4'-DDT) being manufactured with their use drastically restricted since the 1980s. The seasonal differences are mainly due to a higher occurrence of air masses with strong continental inputs in the warm than in the cold periods. In this respect, samples whose air masses traveled at the high troposphere (backward air mass trajectories >6000 m) have been observed to carry considerably smaller PCB and 4,4'-DDE loads (9.3 +/- 2.8 and 0.4 +/- 0.05 pg m(-3), respectively) than overall average.