bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous HONO measurements in and above a forest canopy: influence of turbulent exchange on mixing ratio differences
Authors: Sörgel M. , Trebs I. , Serafimovich A. , Moravek A. , Held A. , Zetzsch C.
Published: January 2011

Abstract. We have combined chemical and micrometeorological measurements to investigate the formation and distribution of HONO throughout a forest canopy. HONO was measured simultaneously at two heights, close to the forest floor and just above canopy. The turbulent exchange between the forest and the atmosphere above was studied using vertical profiles of eddy covariance measurements of wind velocity, sonic temperature, water vapour and CO2. HONO mixing ratios at both heights showed typical diel cycles with low daytime values (~80 ppt) and high nighttime values (up to 500 ppt), but were influenced by various sources and sinks leading to mixing ratio differences (above canopy minus below) of up to +240 ppt at nighttime. In the late afternoon and early night mixing ratios increased at higher rates near the forest floor, indicating a possible ground source. Due to the simultaneous decoupling of the forest from the air layer above the canopy, mixing ratio differences reached about −170 ppt. From the late night until the early morning mixing ratios above the forest were typically higher than close to the forest floor. For some cases, this could be attributed to advection above the forest, which only partly penetrated the canopy. Measured photolysis frequencies above and below the forest canopy differed by a factor of 10–25 resulting in HONO lifetimes of about 10 min above and 100–250 min below the canopy at noontime. However, these differences of the main daytime HONO sink were not evident in the mixing ratio differences, which were close to zero during the morning hours. Effective turbulent exchange due to a complete coupling of the forest to the air layer above the canopy in the morning has offset the differences caused by the daytime photolytic sink and added to the interplay between different HONO production and loss processes.
Technical Note: Propagating correlations in atmospheric inversions using different Kalman update smoothers
Authors: Tang J. , Zhuang Q.
Published: February 2011

Abstract. The scheme to propagate correlations between on-line and off-line state variables in atmospheric inversions using the fixed-lag Kalman smoother proposed in Bruhwiler et al. (2005) is explained as a process to impose a balanced constraint on the on-line state variables. It is then extended to the fixed-lag ensemble square root Kalman smoother and fixed-lag square root sigma-point Kalman smoother, allowing us to treat nonlinear observation operators easily. Further, to constrain the posterior fluxes within their feasible ranges, the constrained fixed-lag Kalman smoother is presented and the variable transform technique is proposed for the other two smoothers. Comparisons between various methods and observational data are conducted using a synthetic inversion of atmospheric CH4 fluxes. The results indicate that our developed methods are good alternatives to existing methods for conducting sequential inversion of atmospheric trace gases. It is also shown that the benefit to include the correlations between on-line and off-line state variables is case dependent.
Primary anthropogenic aerosol emission trends for China, 1990–2005
Authors: Lei Y. , Zhang Q. , He K. B. , Streets D. G.
Published: February 2011

Abstract. An inventory of anthropogenic primary aerosol emissions in China was developed for 1990–2005 using a technology-based approach. Taking into account changes in the technology penetration within industry sectors and improvements in emission controls driven by stricter emission standards, a dynamic methodology was derived and implemented to estimate inter-annual emission factors. Emission factors of PM2.5 decreased by 7%–69% from 1990 to 2005 in different industry sectors of China, and emission factors of TSP decreased by 18%–80% as well, with the measures of controlling PM emissions implemented. As a result, emissions of PM2.5 and TSP in 2005 were 11.0 Tg and 29.7 Tg, respectively, less than what they would have been without the adoption of these measures. Emissions of PM2.5, PM10 and TSP presented similar trends: they increased in the first six years of 1990s and decreased until 2000, then increased again in the following years. Emissions of TSP peaked (35.5 Tg) in 1996, while the peak of PM10 (18.8 Tg) and PM2.5 (12.7 Tg) emissions occurred in 2005. Although various emission trends were identified across sectors, the cement industry and biofuel combustion in the residential sector were consistently the largest sources of PM2.5 emissions, accounting for 53%–62% of emissions over the study period. The non-metallic mineral product industry, including the cement, lime and brick industries, accounted for 54%–63% of national TSP emissions. There were no significant trends of BC and OC emissions until 2000, but the increase after 2000 brought the peaks of BC (1.51 Tg) and OC (3.19 Tg) emissions in 2005. Although significant improvements in the estimation of primary aerosols are presented here, there still exist large uncertainties. More accurate and detailed activity information and emission factors based on local tests are essential to further improve emission estimates, this especially being so for the brick and coke industries, as well as for coal-burning stoves and biofuel usage in the residential sector.
A comparison of different inverse carbon flux estimation approaches for application on a regional domain
Authors: Tolk L. F. , Dolman A. J. , Meesters A. G. C. A. , Peters W.
Published: January 2011

Abstract. We have implemented six different inverse carbon flux estimation methods in a regional carbon dioxide (CO2) flux modeling system for The Netherlands. The system consists of the Regional Atmospheric Mesoscale Modeling System (RAMS) coupled to a simple carbon flux scheme which is run in a coupled fashion on relatively high resolution (10 km). Using an Ensemble Kalman filter approach we try to estimate spatiotemporal carbon exchange patterns from atmospheric CO2 mole fractions over The Netherlands for a two week period in spring 2008. The focus of this work is the different strategies that can be employed to turn first-guess fluxes into optimal ones, which is known as a fundamental design choice that can affect the outcome of an inversion significantly. Different state-of-the-art approaches with respect to the estimation of net ecosystem exchange (NEE) are compared quantitatively: (1) where NEE is scaled by one linear multiplication factor per land-use type, (2) where the same is done for photosynthesis (GPP) and respiration (R) separately with varying assumptions for the correlation structure, (3) where we solve for those same multiplication factors but now for each grid box, and (4) where we optimize physical parameters of the underlying biosphere model for each land-use type. The pattern to be retrieved in this pseudo-data experiment is different in nearly all aspects from the first-guess fluxes, including the structure of the underlying flux model, reflecting the difference between the modeled fluxes and the fluxes in the real world. This makes our study a stringent test of the performance of these methods, which are currently widely used in carbon cycle inverse studies. Our results show that all methods struggle to retrieve the spatiotemporal NEE distribution, and none of them succeeds in finding accurate domain averaged NEE with correct spatial and temporal behavior. The main cause is the difference between the structures of the first-guess and true CO2 flux models used. Most methods display overconfidence in their estimate as a result. A commonly used daytime-only sampling scheme in the transport model leads to compensating biases in separate GPP and R scaling factors that are readily visible in the nighttime mixing ratio predictions of these systems. Overall, we recommend that the estimate of NEE scaling factors should not be used in this regional setup, while estimating bias factors for GPP and R for every grid box works relatively well. The biosphere parameter inversion is best at simultaneously producing space and time patterns of fluxes and CO2 mixing ratios, but non-linearity may significantly reduce the information content in the inversion if true parameter values are far from the prior estimate. Our results suggest that a carefully designed biosphere model parameter inversion or a pixel inversion of the respiration and GPP multiplication factors are the best tools to optimize spatiotemporal patterns of NEE.
On the sub-micron aerosol size distribution in a coastal-rural site at El Arenosillo Station (SW-Spain)
Authors: Sorribas M. , de la Morena B. A. , Wehner B. , López J. F. , Prats N. , Mogo S. , Wiedensohler A. , Cachorro V. E.
Published: February 2011

Abstract. This study is focused on the analysis of the sub-micron aerosol characteristics at rural and coastal environment in Southwestern Spain. Particle number size distributions were measured in the size range (14–673) nm using a Scanning Mobility Particle Sizer (SMPS, Model 3936-TSI), from 15 July 2004 to 31 July 2006 at El Arenosillo Station. Mean total concentration was 8660 cm−3 and mean concentrations for the nucleation, Aitken and accumulation modes particles were 2830 cm−3, 4110 cm−3 and 1720 cm−3, respectively. Mean geometric diameters of the four modes particles, which characterized the mean size distribution per month, were about 16 nm, 42 nm, 103 nm and 237 nm. Two kinds of episodes produced a maximum of the total concentration around noon: the new particle formation and the regional recirculation such as the sea-land breeze. Two types of nucleation events (called N$1 and N2) were observed. Events N1 were an example of the influence of regional sources and Events N2 showed the weight of local industries over the rural and coastal background levels. The 60% of nucleation events were related to NE and NW wind sectors (N1 and N2 respectively), a ΔT higher than 12 °C, a wind speed higher than 2.3 m s−1 and a total surface area for the accumulation mode particles below of 11 190 μ m2 cm−3. The influence of the sea-land breeze processes has been analyzed, observing increases of up to 50%, 110% and 90% of the particle concentration for the nucleation, Aitken and accumulation modes. Annual evolution of monthly averages allowed to conclude that the increase or decrease of 1 cm−3 of the concentration for nucleation mode particles was related to opposite trend of 0.5 cm−3 of the concentration for accumulation mode. This anti-correlation produced a weak seasonal evolution of the total particle concentration.
Revision of the tsunami catalogue affecting Turkish coasts and surrounding regions
Authors: Altinok Y. , Alpar B. , Özer N. , Aykurt H.
Published: February 2011

Abstract. The coasts of Turkey have been hit by tsunamis in the past. The first national earthquake-tsunami catalogues were compiled in the early 1980s while the most up-to-date tsunami catalogues are mainly the products of recent European projects. The EU projects GITEC and GITEC-TWO (Genesis and Impact of Tsunamis on the European Coasts) and TRANSFER (Tsunami Risk ANd Strategies For the European Region) have added important contributions in establishing and developing unified criteria for tsunami parameterisation, standards for the quality of the data, the data format and the database general architecture. On the basis of these new aspects and based on recent marine geophysical data, tsunamigenic earthquakes, tsunami intensities and their reliability have been revised. The current version of the database contains 134 events, most of which have affected the Turkish coasts seriously during the last 3500 years. The reliability index of 76 events was "probable" and "definite", so that they could be used for assessment of the risk along the Turkish coastal region and for implementation of prevention policies.
Empirical correction of XBT fall rate and its impact on heat content analysis
Authors: Hamon M. , Le Traon P. Y. , Reverdin G.
Published: February 2011

Abstract. We used a collocation method between XBT and CTD/OSD (Ocean Station Data including bottle cast and low resolution CTD) from WOD05 (1°×2°×15 days) to statistically correct the XBT fall rate. An analysis of the annual median bias on depth showed that it is necessary to apply a thermal correction linked to probe calibration error, a second order correction on the depth as well as a depth offset representing measurement errors during XBT deployment. We had to separate data in several categories: shallow and deep XBT and deployment sea temperatures (below or above 10 °C). We also processed separately XBT measurements close to Japan between 1968 and 1985 due to large regional biases. Once the corrections have been applied, the analysis of heat content signal is derived from corrected XBT. From this analysis, we confirm that the maximum heat content in the top 700 m found during the 70's in early papers can be explained by the XBT biases. In addition, a trend of 0.32.1022 J/year is observed between the period 1970 and 2008.
Seasonal and inter-annual temperature variability in the bottom waters over the Black Sea shelf
Authors: Shapiro G. I. , Wobus F. , Aleynik D. L.
Published: February 2011

Abstract. Long-term changes in the state of the Bottom Shelf Water (BSW) on the Western shelf of the Black Sea are assessed using analysis of intra- and inter-annual variations of temperature as well as their relations to physical parameters of both shelf and deep-sea waters. First, large data sets of in-situ observations over the 20th century are compiled into high-resolution monthly climatology at different depth levels. Then, the temperature anomalies from the climatic mean are calculated and aggregated into spatial compartments and seasonal bins to reveal temporal evolution of the BSW. For the purpose of this study the BSW is defined as such shelf water body between the seabed and the upper mixed layer (bounded by the σθ = 14.2 isopycnal) which has limited ability to mix vertically with oxygen-rich surface waters during the warm season (May–November) due to the formation of a seasonal pycnocline. The effects of atmospheric processes at the surface on the BSW are hence suppressed as well as the action of the "biological pump". The vertical extent of the near- bottom waters is determined based on energy considerations and the structure of the seasonal pycnocline, whilst the horizontal extent is controlled by the shelf break, where strong along-slope currents hinder exchanges with the deep sea. The BSW is shown to occupy nearly half of the area of the shelf during the summer stratification period. The potential of the BSW to ventilate horizontally during the warm season with the deep-sea waters is assessed using isopycnic analysis of temperature variations. A long-term time series of temperature anomalies in the BSW is constructed from observations during the May–November period for the 2nd half of the 20th century. The results reveal a warm phase in the 1960s/70s, followed by cooling of the BSW during 1980–2001. The transition between the warm and cold periods coincides with a regime shift in the Black Sea ecosystem. While it was confirmed that the memory of winter convection events is well preserved over the following months in the deep sea, the signal of winter cooling in the Bottom Shelf Waters significantly reduces during the warm season. The time series of temperature in the BSW is highly correlated with the temperature of Cold Intermediate Waters in the deep sea thus indicating that the isopycnal exchanges with the deep sea are more important for inter-annual/inter-decadal variability of the BSW on the Western Black Sea shelf than winter convection on the shelf itself.
Bone Metabolism Analyzed by Pet and Dxa following Revision tha Using A Distally Fixed Stem. A Pilot Study
Authors: Ullmark Gösta , Kärrholm Johan , Sörensen Jens
Published: January 2011

In a pilot study we analyzed bone remodeling using18F-PET (positon emission tomography) scanning or DXA (dual-energy x-ray absorptiometry) in 3 patient groups, one with a loose femoral stem and 2 after revision using a modular stem (MP). In loose implants (group 1), bone formation activity compared to the contralateral healthy femur was 261 %. In the proximal part of the femur bone formation was increased by 253 % one week after revision (group 2) and did not normalize within 1 year. In the distal region it decreased to normal after one year. In the second revision group DXA showed decreased bone mineral density at 6 and 24 months (group 3).

The PET technique provided evidence of bone healing despite osteolysis and prosthetic loosening which continued after revision. Decreasing BMD after revision in the third group is multifactorial, but suggests that despite intensive bone formation resorption was still higher.
Amorphous Carbon Coated High Grain Boundary Density Dual Phase Li4Ti5O12‐TiO2: A Nanocomposite Anode Material for Li‐Ion Batteries
Authors: Rahman Md. Mokhlesur , Wang Jia‐Zhao , Hassan Mohd Faiz , Wexler David , Liu Hua Kun
Published: February 2011

This work introduces an effective, inexpensive, and large‐scale production approach to the synthesis of a carbon coated, high grain boundary density, dual phase Li4Ti5O12‐TiO2 nanocomposite anode material for use in rechargeable lithium‐ion batteries. The microstructure and morphology of the Li4Ti5O12‐TiO2‐C product were characterized systematically. The Li4Ti5O12‐TiO2‐C nanocomposite electrode yielded good electrochemical performance in terms of high capacity (166 mAh g−1 at a current density of 0.5 C), good cycling stability, and excellent rate capability (110 mAh g−1 at a current density of 10 C up to 100 cycles). The likely contributing factors to the excellent electrochemical performance of the Li4Ti5O12‐TiO2‐C nanocomposite could be related to the improved morphology, including the presence of high grain boundary density among the nanoparticles, carbon layering on each nanocrystal, and grain boundary interface areas embedded in a carbon matrix, where electronic transport properties were tuned by interfacial design and by varying the spacing of interfaces down to the nanoscale regime, in which the grain boundary interface embedded carbon matrix can store electrolyte and allows more channels for the Li+ ion insertion/extraction reaction. This research suggests that carbon‐coated dual phase Li4Ti5O12‐TiO2 nanocomposites could be suitable for use as a high rate performance anode material for lithium‐ion batteries.
Injuries on the fireground: Risk factors for traumatic injuries among professional fire fighters
Authors: Helneman Ellen F. , Shy Carl M. , Checkoway Harvey
Published: February 2011

This case‐control study within a metropolitan fire department evaluated the effect of self‐contained breathing apparatus (SCBA) and other risk factors on three types of injury at the scene of a fire (smoke inhalation, burns, and falls). Data on 75 injured fire fighters and 144 controls came from telephone interviews and department records. The two sets of uninjured fire‐fighter controls were matched to cases on incident (n = 72) or on job position and fire type and size (n = 72). Smoke inhalation cases were not significantly different from controls in SCBA use, cigarette smoking, previous fires in the shift, or injury history. Jobs with high risk of burns included nozzle operator, engine officer, and forcible‐entry person in first‐due companies (OR = 20.1). Other risk factors for burns were: basement origin of fire (OR = 10.2); prior fire‐fighting training outside the present department (same fire: OR = 11.2; similar fire: OR = 3.9); and on‐duty injury in the prior 12 months (same fire: OR = 4.3; similar fire: OR = 3.5). When other risk factors were considered, consistent SCBA use was associated with falls (same fire: OR = 11.8; similar fire: OR = 4.3) but not with burns. Risk of falls also was elevated among members of truck companies (OR = 17.7) and fire fighters without children (same fire: OR = 8.4; similar fire: OR = 7.4). On‐duty injury in the past 12 months was associated with falls when one compared cases with similar‐fire controls (OR = 5.5), but not with controls attending the same fire. Neither age nor experience was related to injury in this population.
Critical review of cancer epidemiology in petroleum industry employees, with a quantitative meta‐analysis by cancer site
Authors: Wong Otto , Raabe Gerhard K.
Published: February 2011

A critical review of close to 100 published and unpublished but otherwise available epidemiologic reports of petroleum industry employees from the United States, United Kingdom, Canada, Europe, Australia, and Japan was conducted. Analyses by duration of employment and latency are discussed, and summary standardized mortality ratios (SMRs) or meta‐SMRs are developed for selected cancer sites. Findings indicate that the industry experienced a significantly lower cancer mortality than the general population for all cancer sites combined, digestive system, stomach, and lung. For the industry as a whole, SMRs similar to the general population were observed for skin, brain, pancreatic, prostatic, and kidney cancers. However, some data indicate that certain small groups within the industry might have elevated prostatic and kidney cancer risk. This review supports the conclusion that some refinery employees, particularly those employed before the 1940s, may have been at increased risk of leukemia. There is some indication that cancer of other lymphatic tissue may also be elevated. Unresolved issues affecting these conclusions are discussed, and specific directions for future research are offered.
NMR QSAR Model for the Analysis of 4‐(5‐Arylamino‐1,3,4‐thiadiazol‐2‐yl)benzene‐1,3‐diols
Authors: Matysiak Joanna , Niewiadomy Andrzej , Paw Beata , Dybała Izabela
Published: February 2011

We have developed a NMR data quantitative structure‐activity relationship NMR‐QSAR model based on 1H‐ and 13C‐NMR experimental spectral data of 4‐(5‐arylamino‐1,3,4‐thiadiazol‐2‐yl)benzene‐1,3‐diols. Compounds show in‐vitro antiproliferative activity against some human cancer cell lines. Two‐parameter equations obtained by the multiple linear regression procedure showed that chemical shifts of the protons of hydroxyl groups and carbon atoms of the 1,3,4‐thiadiazole ring are the decisive descriptors of inhibition interactions of the compounds. The models gave leave‐one‐out (LOO) cross‐validation ranges from 78% to 93%. The obtained NMR‐QSAR equations provide a rapid, reliable, and simple way for predicting the antiproliferative activity of N‐substituted 4‐(5‐amino‐1,3,4‐thiadiazol‐2‐yl)benzene‐1,3‐diols.
4,5‐Diaryl‐3‐aminopyrazole Derivatives as Analogs of Combretastatin A‐4: Synthesis and Biological Evaluation
Authors: Liu Tao , Cui Rong , Chen Jing , Zhang Jun , He Qiaojun , Yang Bo , Hu Yongzhou
Published: February 2011

A series of cis‐restricted 4,5‐diaryl‐3‐aminopyrazole derivatives were synthesized and tested for their cytotoxic activity in vitro against five human cancer cell lines (K562, ECA‐109, A549, SMMC‐7721, and PC‐3). Compounds 5a, 5b, 5d, and 6b showed potent cytotoxicity against all tested cell lines. Primary mechanism research on compound 5a indicated that it was a potent inhibitor of tubulin polymerization, arresting cell cycle in G2/M phase. The docking research showed the conformation of 5a overlaps well with CA‐4 in the crystallized protein complex, suggesting the 4,5‐diaryl‐3‐aminopyrazoles were good mimics of CA‐4.
The free‐radical damage theory: Accumulating evidence against a simple link of oxidative stress to ageing and lifespan
Authors: Speakman John R. , Selman Colin
Published: February 2011

Recent work on a small European cave salamander (Proteus anguinus) has revealed that it has exceptional longevity, yet it appears to have unexceptional defences against oxidative damage. This paper comes at the end of a string of other studies that are calling into question the free‐radical damage theory of ageing. This theory rose to prominence in the 1990s as the dominant theory for why we age and die. Despite substantial correlative evidence to support it, studies in the last five years have raised doubts over its importance. In particular, these include studies of mice with the major antioxidant genes knocked out (both singly and in combination), which show the expected elevation in oxidative damage but no impact on lifespan. Combined, these findings raise fundamental questions over whether the free‐radical damage theory remains useful for understanding the ageing process, and variation in lifespan and life histories.

Editor's suggested further reading in BioEssays Blind cave salamanders age very slowly: A new member of Methuselah's Bestiary Abstract
Of circles, forks and humanity: Topological organisation and replication of mammalian mitochondrial DNA
Authors: Pohjoismäki Jaakko L. O. , Goffart Steffi
Published: February 2011

The organisation of mammalian mitochondrial DNA (mtDNA) is more complex than usually assumed. Despite often being depicted as a simple circle, the topology of mtDNA can vary from supercoiled monomeric circles over catenanes and oligomers to complex multimeric networks. Replication of mtDNA is also not clear cut. Two different mechanisms of replication have been found in cultured cells and in most tissues: a strand‐asynchronous mode involving temporary RNA coverage of one strand, and a strand‐coupled mode rather resembling conventional nuclear DNA replication. In addition, a recombination‐initiated replication mechanism is likely to be associated with the multimeric mtDNA networks found in human heart. Although an insight into the general principles and key factors of mtDNA organisation and maintenance has been gained over the last few years, there are many open questions regarding replication initiation, termination and physiological factors determining mtDNA organisation and replication mode. However, common themes in mtDNA maintenance across eukaryotic kingdoms can provide valuable lessons for future work.
Ceftriaxone ameliorates cyclosporine A‐induced oxidative nephrotoxicity in rat
Authors: Yılmaz Nigar , İlhan Selçuk , Nazıroğlu Mustafa , Oktar Süleyman , Nacar Ahmet , Arıca Vefik , Tutanç Murat
Published: February 2011

A growing body of evidence now suggested that cyclosporine A (CycA)‐induced nephrotoxicity is a crucial clinical problem and oxidative stress is importantly responsible for its toxicity. Ceftriaxone induced antioxidant effect in brain and neuronal tissues against oxidative damage although its antioxidant potential effect on kidney has not been clarified. The aim of this study was to evaluate whether ceftriaxone protects CycA‐induced oxidative stress kidney injury in rats. Twenty‐four rats were equally divided into four groups. First group was used as control. Ceftriaxone (200 mg/kg) and CycA (15 mg/kg) were administrated to second and third groups for 10 days, respectively. The ceftriaxone and CycA combination was given to rats constituting the fourth group for 10 days. Lipid peroxidation (LP), urea nitrogen and lactate dehydrogenase (LDH) levels were higher in CycA group than in control and ceftriaxone groups although LP, urea nitrogen and LDH levels were lower in ceftriaxone + CycA group than in control and ceftriaxone groups. Glutathione peroxidase and catalase activities were lower in CycA group than in control whereas their activities were increased in control and ceftriaxone groups. Superoxide dismutase activity did not change by the treatments. Ceftriaxone administration recovered also CycA‐induced atrophy, vacuolization and exfoliations of tubular epithelium and glomerular collapse in histopathological evaluation of kidney. In conclusion, we observed that ceftriaxone is beneficial on CycA‐induced oxidative stress in kidney of rats by modulating oxidative and antioxidant system. Copyright © 2011 John Wiley & Sons, Ltd.
Induction of MiR‐17‐3p and MiR‐160a by TNFα and LPS
Authors: Jiang Xin , Li Nancy
Published: February 2011

MicroRNAs (miRNAs), small non‐coding molecules, regulate gene expression in response to stimuli. Lipopolysaccharide (LPS) was reported to induce the expression of miR‐146 and miR‐155 in HL‐60. The effects of LPS and the related stimulus, tumour necrosis factor alpha (TNFα), on miRNA expression required to be further studied. Using T7‐oligo ligation assay (OLA)‐based miRNA array, we profiled the expression of 132 miRNAs and identified a number of TNFα‐regulated miRNAs in HeLa cells, including miR‐17‐3p and miR‐106a. TNFα induction of miR‐17‐3p and miR‐106a was verified by Northern blot analysis with RNU48 normalization. Northern blot analysis also showed that LPS was able to induce the expression of both miR‐17‐3p and miR‐106a in HeLa cells. Furthermore, both array assay and Northern blot analysis showed that the expression levels of miR‐146 and miR‐155 were either low or undetectable in HeLa cells and TNFα‐ and LPS‐mediated induction of these two miRNAs was not found. Luciferase reporter analysis confirmed the induction of miR‐17‐3p and miR‐106a in response to TNFα and LPS treatment in HeLa cells. These results suggested that the expression of miR‐17‐3p and miR‐106a is regulated by TNFα and LPS in HeLa cells. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of ubiquitin carboxy‐terminal hydrolase 37 on apoptotic in A549 cells
Authors: Chen Zhiwei , Niu Xiaomin , Li Ziming , Yu Yongfeng , Ye Xiangyun , Lu Shun , Chen Zhen
Published: February 2011

Proteins destined for degradation by the ubiquitin‐proteasome system are labelled with a 76‐amino acid peptide, ubiquitin, through a series of conjugation steps by the E1, E2 and E3 enzymes respectively. Ubiquitin carboxy‐terminal hydrolase 37 (UCH37) belongs to the UCH proteases family that deubiquitinates ubiquitin‐protein conjugates in the ubiquitin‐proteasome system. However, it is few reports about the relationship between UCH37 and apoptosis. In order to clarify the role of UCH37 on apoptosis, the A549 cells were chosen for this study. We transfected UCH37 siRNA and pcDNA3.1‐UCH37 plasmid into A549 cells, respectively. Using MTT assay, Western blot, Hoechst 33342 staining assay and flow cytometry, we found that silencing of UCH37 in A549 cells induced apoptosis. The ratio of Bax/Bcl‐2 was higher in silencing of UCH37 than that in control group after silencing of UCH37 in A549 cells. Meanwhile, experiments with the A549 cell line disclose that silencing of UCH37 could induce efficiently A549 cell apoptosis through activation of caspase‐9 and caspase‐3. On the other hand, over‐expression of UCH37 led to the opposite effect. Hence, UCH37 might play an important role in apoptotic through altering Bax/Bcl‐2 ratio and enzymatic activities of caspase‐9 and caspase‐3. Copyright © 2011 John Wiley & Sons, Ltd.
In‐line monitoring of Saccharomyces cerevisiae fermentation with a fluorescence probe: new approaches to data collection and analysis
Authors: Bogomolov Andrey , Grasser Thorsten , Hessling Martin
Published: February 2011

Fluorescence analysis, in particular two‐dimensional excitation‐emission matrix (EEM) spectroscopy, is a sensitive in‐line process monitoring tool in the biotechnological production. Before it can be widely adopted by the industry, fast effective algorithms for the analysis of massive and complex fluorescence data should be developed. Weak emission signals are prone to various interferences complicating the modeling, such as excitation light Rayleigh scatter. The scatter is usually considered as an unwanted background to be avoided or removed.

This work is focused on effective usage of the entire spectral information. It has been shown that scatter peaks coming from the excitation or an external light source can be used in the data analysis to improve the performance of a multivariate model. A new fluorescence Lighthouse Probe™ (LHP) has been applied in‐line to monitor Saccharomyces cerevisiae fermentation in a lab reactor. Exploratory data analysis of two fed‐batch cultivations has been performed using Partial Least Squares regression and Multivariate Curve Resolution. A simple algorithm for the resolution of process profiles and two‐dimensional spectra of individual fluorophores from three‐way fluorescence data in the presence of intensive scatter has been suggested and applied to the process diagnostics. Copyright © 2011 John Wiley & Sons, Ltd.
Molybdenum‐Catalyzed Asymmetric Allylic Alkylation of 3‐Alkyloxindoles: Reaction Development and Applications
Authors: Trost Barry M. , Zhang Yong
Published: February 2011

We report a full account of our work towards the development of Mo‐catalyzed asymmetric allylic alkylation reactions with 3‐alkyloxindoles as nucleophiles. The reaction is complementary to the Pd‐catalyzed reaction with regard to the scope of oxindole nucleophiles. A number of 3‐alkyloxindoles were alkylated successfully under mild conditions to give products with excellent yields and good‐to‐excellent enantioselectivities. Applications of this method to the preparation of indoline alkaloids such as (−)‐physostigmine, ent‐(−)‐debromoflustramine B, and the indolinoquinoline rings of communesin B are reported.
Kinetic and Theoretical Studies on Alkaline Ethanolysis of 4‐Nitrophenyl Salicylate: Effect of Alkali Metal Ions on Reactivity and Mechanism
Authors: Um Ik‐Hwan , Seo Jin‐A , Mishima Masaaki
Published: February 2011

Pseudo‐first‐order rate constants (kobsd) for reactions of 4‐nitrophenyl salicylate (7) with alkali metal ethoxides (EtOM, M=K, Na, and Li) in anhydrous ethanol have been measured spectrophotometrically. Interestingly, the kobsd value decreases significantly as the concentration of EtOM increases. Because the phenolic moiety of substrate 7 would be deprotonated and exist as an anionic form (i.e., 7−) under kinetic conditions, the ground‐state stabilization of 7− through formation of a six‐membered cyclic complex with M+ (i.e., 8) is proposed to be responsible for the decreasing kobsd trend. The kobsd value at a given concentration of EtOK increases steeply upon addition of [18]crown‐6 ether (18C6) up to [18C6]/[EtOK]=1 in the reaction mixture and then remains relatively constant thereafter. In contrast, kobsd decreases upon addition of salts (e.g., LiClO4 or KSCN) to the reaction mixture, which indicates that M+ ions inhibit the reaction. However, in the presence of 18C6, the kobsd value is independent of the concentration of EtOK but remains constant, which indicates that the reaction proceeds through a unimolecular mechanism in the presence of the complexing agent. Although two conceivable unimolecular pathways (formation of ketene 9 and lactone 10) can account for the kinetic results, the reaction has been concluded to proceed via formation of ketene 9 as the reactive intermediate on the basis of theoretical calculations.
Haloperoxidase Activity of Oxovanadium(V) Thiobisphenolates
Authors: Werncke C. Gunnar , Limberg Christian , Knispel Christina , Metzinger Ramona , Braun Beatrice
Published: February 2011

By employing the 2,2′‐thiobis(2,4‐di‐tert‐butylphenolate) ligand (SL2−) a novel oxovanadium(V) complex, (PPh4)2[SLV(O)(μ2‐O)2V(O)SL] (1), was synthesised that exhibits haloperoxidase activity: on addition of H2O2 a sequence of successive peroxide formation and intramolecular thioether oxidation events (sulfoxide and sulfone) led to a mixture of five products, which were all identified unambiguously, partly through an independent synthesis and characterisation. It was shown that internal thioether oxidation proceeds through peroxide formation, but the sulfoxidation of external thioether functions requires further activation of the peroxide function by protons or alkyl cations. Consistently, the employment of tBuOOH instead of H2O2 led to a very active system for the catalytic sulfoxidation of thioethers.
Das kalte Licht der Olefine
Authors: Albrecht Steffen , Brandl Herbert , Ciscato Luiz Frazisco Monteiro Leite , Weiß Dieter , Augustin Dieter , Zimmermann Thomas
Published: February 2011

Der folgende Artikel setzt die Reihe unserer ChiuZ‐Beiträge zur Chemi‐ und Biolumineszenz mit einer interessanten und neuen experimentellen Arbeit zum “kalten Licht” spezieller ungesättigter Verbindungen fort, deren Anwendung auch in der modernen Zeit der Nanotechnologie im biochemischen bzw. medizinisch‐chemischen Labor völlig neue Akzente gesetzt hat.
Was verbindet zelluläre Virusabwehr und Vesikeltransport?
Authors: Hille‐Rehfeld Annette
Published: February 2011

Virale Krankheitserreger können auch bei der Erstinfektion schnell außer Gefecht gesetzt werden. Im Rahmen der angeborenen Immunantwort der Wirbeltiere werden dafür – ausgelöst durch den Immunmediator Interferon – in infizierten Zellen Resistenzproteine gebildet, die eingedrungene Viren an der Vermehrung hindern. Myxovirus‐Resistenzproteine beispielsweise schützen vor einem weiten Spektrum an RNA‐ und DNA‐Viren einschließlich Influenza A, B und C. Sie gehören zur Proteinfamilie der Dynamin‐GTPasen. Das namensgebende Dynamin ist ein membranassoziiertes Protein, das die Bildung von Membranvesikeln des intrazellulären Transports unterstützt. Ein Strukturmodell des humanen Myxovirus‐Resistenzprotein1 lieferte jetzt eine Vorstellung von den molekularen Grundlagen der Virusabwehr.
Cyclopentadienyl‐Analoga mit Bor und Blei
Authors: Jaenicke Lothar
Published: February 2011

Die Cyclopentadien‐Chemie sorgt immer wieder für Überraschungen. Die Hückel‐Frage nach dem aromatischen Zustand der Metallole ist nicht zum Ende des Periodischen Systems durchdiskutiert, und auch ganz am Anfang stehen mit den Borolen noch immer neue Perspektiven.
Eine vollsynthetische Diels‐Alderase
Authors: Harrer Rowitha
Published: February 2011

Passt, quietscht, sitzt und hat Luft: Um den Übergangszustand der wichtigen Diels‐Alder‐Reaktion herum wurde das aktive Zentrum eines neuen Enzyms maßgeschneidert. Zum ersten Mal wurde für eine solch anspruchsvolle Reaktion ein Enzym von Grund auf modelliert, hergestellt und getestet.
Real‐time 3D MRI of contrast agents in whole living mice
Authors: Bled Emilie , Hassen Wadie Ben , Pourtau Line , Mellet Philippe , Lanz Titus , Schüler Dorothee , Voisin Pierre , Franconi Jean‐Michel , Thiaudière Eric , Miraux Sylvain
Published: February 2011

A specific mouse whole body coil and a dedicated gradient system at 4.7 T were coupled with an ultra‐fast 3D gradient echo MRI and keyhole reconstruction technique to obtain 3D whole‐body dynamic T1‐weighted or T2*‐weighted imaging. The technique was used to visualize the real‐time distribution of non‐targeting T1 and T2* contrast agent (CA) in a glioma‐bearing mouse model. T1 dynamic contrast‐enhancement imaging was performed with a fast imaging with steady‐state precession sequence [echo time/repetition time (TE/TR), 1.32/3.7 ms] before and after CA injection (Gd–DOTA and BSA–Gd–DOTA) for 21 min. The temporal resolution was 1 image/6.5 s. T2* imaging (TE/TR, 4/8 ms) was performed before and after iron‐based (small and ultra‐small particles of iron oxide) CA injection for 45 min. The temporal resolution was 1 image/14 s. Signal‐to‐noise ratio curves were determined in various mouse organs. The whole‐body coil and gradient systems made it possible to acquire data with sufficient and homogeneous signal‐to‐noise ratio on the whole animal. The spatial resolution allowed adequate depiction of the major organs, blood vessels and brain glioma. The distribution and the time‐course of T1 and T2* contrasts upon contrast agent injection were also assessed. 3D whole‐body mouse MRI is feasible at high spatial resolution in movie mode and can be applied successfully to visualize real‐time contrast agent distribution. This method should be effective in future preclinical molecular imaging studies. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of tempereature on Struvite precipitation by CO2‐deagassing method
Authors: Ben Moussa S. , Tlili M. M. , Batis N. , Amor M. Ben
Published: February 2011

The present study explores struvite precipitation by degassing method under different temperature (14.5‐35 °C). It is shown that an increase of temperature does not affect the nucleation kinetics but strongly influences the growth rate and the efficiency of the phosphate removal. This was attributed to the effect of temperature on the struvite solubility and then the reached supersaturation coefficient. It was also shown, by using degassing method, that the determined solubility constant (pKs) values of struvite, at 14.5, 20, 25 and 35 °C are 13.00, 12.82, 12.63 and 13.20, respectively, are close to those presented in the literature. The results show that temperature influences the kinetics of precipitation. First‐order kinetics were found to be sufficient to describe the rate data. The rates decreased with increasing temperature and the apparent rate constants for the reaction were determined. Arrhenius plots yielded a relatively apparent high activation energy Ea = 31.0 kJ·mol–1. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of methyloxime derivatives of intact esters of testosterone and boldenone in equine plasma using ultra high performance liquid chromatography tandem mass spectrometry
Authors: Gray Bobby P. , Teale Phil , Pearce Clive M.
Published: February 2011

Analysis of equine plasma samples to detect the abuse of anabolic steroids can be complicated when the parent steroid is endogenous to the animal. Anabolic steroids are usually administered intramuscularly as synthetic esters and therefore detection of the exogenous esters provides unequivocal proof of illegal administration. An ultra high performance liquid chromatography tandem mass spectrometric (UPLC‐MSMS) method for the analysis of esters of testosterone (propionate, phenylpropionate, isocaproate, and decanoate) and boldenone (undecylenate) in equine plasma has been developed. Esters were extracted from equine plasma using a mixture of hexane and ethyl acetate and treated with methoxyamine hydrochloride to form methyloxime derivatives. Metenolone enanthate was used as an internal standard. After chromatographic separation, the derivatized steroid esters were quantified using selected reaction monitoring (SRM). The limit of detection for all of the steroid esters, based on a signal to noise ratio (S/N) of 3:1, was 1–3 pg/mL. The lower limit of quantification (LLOQ) for the all of the steroid esters was 5 pg/mL when 2 mL of plasma was extracted. Recovery of the steroid esters was 85–97% for all esters except for testosterone decanoate which was recovered at 62%. The intra‐day coefficient of variation (CV) for the analysis of plasma quality control (QC) samples was less than 9.2% at 40 pg/mL and less than 6.0% at 400 pg/mL. The developed assay was used to successfully confirm the presence of intact testosterone esters in equine plasma samples following intramuscular injection of Durateston® (mixed testosterone esters). Copyright © 2011 John Wiley & Sons, Ltd.
Enzyme‐assisted synthesis of the glucuronide conjugate of psilocin, an hallucinogenic component of magic mushrooms
Authors: Shoda Takuji , Fukuhara Kiyoshi , Goda Yukihiro , Okuda Haruhiro
Published: February 2011

An enzyme‐assisted synthesis of psilocin glucuronide (PCG), a metabolite excreted in the urine of magic mushroom (MM) users, is described. In the presence of Aroclor 1254 pretreated rat liver microsomes, psilocin and the cofactor UDPGA were incubated for 20 h. Purification by HPLC gave PCG in 19% yield (3.6 mg). The compound structure was characterized by MS and NMR. The milligram amounts of PCG produced by this method will allow the direct identification and quantification of PCG in the urine of MM users. Copyright © 2011 John Wiley & Sons, Ltd.
Tailor‐Made Modification of a Gold Surface for the Chemical Binding of a High‐Activity [FeFe] Hydrogenase
Authors: Krassen Henning , Stripp Sven T. , Böhm Nadine , Berkessel Albrecht , Happe Thomas , Ataka Kenichi , Heberle Joachim
Published: February 2011

Hydrogenases are iron–sulfur proteins that catalyze hydrogen turnover in a wide range of microorganisms. Three different classes have been described, and among these [FeFe] hydrogenases are the most active in H2 evolution. Hydrogenases are redox enzymes that have been shown to exchange electrons with graphite and modified noble metal electrodes. Making use of the latter, diffusible electron carriers are required to enable redox catalysis, as proteins do not specifically bind to the electrode surface. Diffusion‐limited electron transfer can be replaced by electron injection into immobilized hydrogenase by binding the redox mediator to the electrode surface. Here, we present the synthesis and spectroelectrochemical characterization of 1‐(10‐mercaptodecyl)‐1′‐benzyl‐4,4′‐bipyridinium dibromide (MBBP), which is used as redox‐active linker. CrHydA1, the high‐activity [FeFe] hydrogenase from Chlamydomonas reinhardtii, is immobilized on the linker‐modified gold electrode. Each surface modification step is controlled in situ by surface‐enhanced infrared absorption spectroscopy (SEIRAS). Functionality of the electrode–protein hybrid is demonstrated by recording the linker‐supported current. The specificcatalytic rate of hydrogen evolution by CrHydA1 (2.9 μmol H2 min–1 mg–1 hydrogenase) promises a valuable approach for further optimization of this novel bioelectrical interface.
AC field induced‐charge electroosmosis over leaky dielectric blocks embedded in a microchannel
Authors: Zhao Cunlu , Yang Chun
Published: February 2011

An effective electrical boundary condition is formulated to describe AC field‐driven induced‐charge electrokinetic (ICEK) phenomena at the interface between a liquid and a leaky dielectric solid. Since most materials in reality possess finite dielectric and conductive properties, i.e. leaky dielectric, the present boundary condition can be used to describe the induced zeta potential on a leaky dielectric surface with consideration of both bond charges (due to polarization) and free charges (due to conduction). Two well‐known limiting cases, i.e. the perfectly dielectric and the perfectly conducting wall boundary conditions can be recovered from the present formulation. Utilizing the derived boundary condition, we obtain analytical solutions in closed form for the AC field‐driven induced‐charge electroosmosis (ICEO) over two symmetric leaky dielectric blocks embedded in the walls of an infinitely long microchannel. Two important factors for the induced zeta potential are identified to respectively account for the polarization charges and the free charges, and their effects on AC field‐driven ICEO oscillating flow patterns are analyzed. It is found that the flow patterns exhibit two counter‐rotating vortices, which can be deformed, relocated, eliminated and even reverse their rotating directions. It is very promising that such temporary evolution of flow patterns can possibly induce chaotic advection which can enhance microfluidic mixing.
Extracellular alkaline protease from Bacillus licheniformis NCIM‐2042: Improving enzyme activity assay and characterization
Authors: Bhunia Biswanath , Dutta Debjani , Chaudhuri Surabhi
Published: February 2011

Optimization of enzyme assay conditions for alkaline protease from Bacillus licheniformis NCIM‐2042 was carried out by a statistical approach. Four key determinants such as pH, temperature, buffer concentration, and incubation time were optimized by response surface methodology using rotatable central composite design. Maximum enzyme activity was found to be at pH 9.0, temperature 75°C in phosphate buffer (50 mM) when incubated for 10 min. Protease was stable over a broad range of pH 6.0–12.0 and it was stable at 50°C for 1 h. The protease was completely inhibited by PMSF (5 mM), suggesting that the enzyme is a serine alkaline protease. This enzyme had good stability in the presence of H2O2, SDS, Triton X‐100, and retained more than 88% of its initial activity after preincubation for 30 min at room temperature in the presence of 25% v/v DMSO, methanol, ethanol, ACN, and 2‐propanol.