bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of the European Russia drought in 2010 on the Caspian Sea level
Authors: Arpe K. , Leroy S. A. G. , Lahijani H. , Khan V.
Published: January 2012

Abstract. The hydrological budgets of the Volga basin (VB) and the Caspian Sea (CS) have been analysed. The components of the water balance for the CS were calculated for the period 1993 to 2010 with emphasis on summer 2010 when a severe drought developed over European Russia. A drop in precipitation over the VB in July 2010 occurs simultaneously with a decrease in evaporation for the same area, an increase of evaporation over the CS itself and a drop of the Caspian Sea level (CSL). The drop in the precipitation over the VB cannot lead to an instantaneous drop of the CSL because the precipitated water needs some months to reach the CS. The delay is estimated here to be 1 to 3 months for excessive precipitation in summer, longer for deficient precipitation and for winter cases. However, the evaporation over the CS itself is considered to be responsible for a simultaneous drop of the CSL from July to September 2010. The impact on the CSL from the precipitation deficit over the VB occurs in the months following the drought. The water deficit from July to September 2010 calculated from the anomalous precipitation minus evaporation over the VB would decrease the CSL by 22 cm, of which only 2 cm had been observed until the end of September (observed Volga River discharge anomaly). So the remaining drop of 20 cm can be expected in the months to follow if no other anomalies happen. In previous studies the precipitation over the VB has been identified as the main cause for CSL changes, but here from a 10 cm drop from beginning of July to end of September, 6 cm can be directly assigned to the enhanced evaporation over the CS itself and 2 cm due to reduced precipitation over the CS. Further periods with strong changes of the CSL are also investigated, which provide some estimates concerning the accuracy of the analysis data. The investigation was possible due to the new ECMWF interim reanalysis data which are used to provide data also for sensitive quantities like surface evaporation and precipitation. The comparison with independent data and the consistency between such data for calculating the water budget over the CS gives a high confidence in the quality of the data used. This investigation provides some scope for making forecasts of the CSL few months ahead to allow for mitigating societal impacts.
Trends for snow cover and river flows in the Pamirs (Central Asia)
Authors: Chevallier P. , Pouyaud B. , Mojaïsky M. , Bolgov M. , Olsson O. , Bauer M. , Froebrich J.
Published: January 2012

Abstract. In the often discussed Aral Sea basin (Central Asia), water availability depends essentially on the high mountains located in its eastern part, especially from the Pamir Alay Range where the Vakhsh and Pyandj Rivers, the main tributaries of the Amu Darya River, flow. In this region, the cryosphere, glaciers, and snow cover significantly impact the water cycle and the flow regime, which could be deeply modified by climate change. The present study, part of a project funded by the EU FP6, analyzes the hydrological situation in six benchmark basins covering areas between 1800 and 8400 km2, essentially located in Tajikistan, with a variety of topographical situations, precipitation amounts, and glacierized areas. Four types of parameter are discussed: temperature, glaciers, snow cover, and river flows. Two time periods are considered: (i) a long time series ending in the 1990s with the collapse of the Soviet Union and based on field observations and data collection; (ii) a May 2000 to May 2002 interval, using scarce monitored data and satellite information to follow snow cover dynamics. The results confirm the global homogeneous trend of temperature increase in the mountain range and its impacts on the surface water regimes. Concerning the snow cover, significant differences are noted regarding the location, the elevation, the orientation and the morphology of the respective basins. Finally the expected changes in the flow river regime are regulated by the combination of the snow cover dynamics and the increasing trend of the air temperature. It confirms the high sensitivity of this region to the warming as identified by the 4rd IPCC Assessment Report.
Tree ring-based reconstruction of October to November runoffs in the Jiaolai River since 1826
Authors: Ma L. , Liu T. X. , Wu Q. , Ji L. H. , Gao R. Z.
Published: January 2012

Abstract. The Horqin Sandy Land is a typical desertification region in China hounded by ecological and environmental problems, which continue to affect economic and social development.Hence,hydrological climate changes in this region need to be investigated. The current study reconstructed the runoff sequences in the southwest edge of the LiaoHe River into the XiaWa station of the JiaoLai River during the months of October to November from 1826 to 2005. A comprehensive timeline for the regional tree wheel width of the Horqin Sandy Land was employed. The timeline has been in use for 183 yr. For the past 180 yr, the runoff has experienced six and four consecutive Feng and dry sections, respectively. From 1982 to 2005, the runoff reached the longest section of a continuous low-flow runoff, with the mean average runoff amounting to only 63.58% of the entire period. Runoff has 3-, 11-, 15-, 24-, and 30-yr quasi-periodic variations, consistent with changes in similar areas worldwide. The period of 1826 to 1917 presents a more gentle change. In 1956, the runoff increased, and then significantly decreased for nearly 50 yr. The drop rate is 1.7766 million m3/10 yr, which shows a consistent downward trend with the precipitation (14.74 mm/10 yr). The overall reduction in precipitation accounts for 29.86% of the initial value, which is far less than 75.58% of the runoff. If the runoff and precipitation drop continue, more extensive and longer ecological and environmental problems are foreseen to occur.
Nonlinear wave effects at the non-reflecting beach
Authors: Didenkulova I. , Pelinovsky E.
Published: January 2012

Abstract. Nonlinear effects at the bottom profile of convex shape (non-reflecting beach) are studied using asymptotic approach (nonlinear WKB approximation) and direct perturbation theory. In the asymptotic approach the nonlinearity leads to the generation of high-order harmonics in the propagating wave, which result in the wave breaking when the wave propagates shoreward, while within the perturbation theory besides wave deformation it leads to the variations in the mean sea level and wave reflection (waves do not reflect from "non-reflecting" beach in the linear theory). The nonlinear corrections (second harmonics) are calculated within both approaches and compared between each other. It is shown that for the wave propagating shoreward the nonlinear correction is smaller than the one predicted by the asymptotic approach, while for the offshore propagating wave they have a similar asymptotic. Nonlinear corrections for both waves propagating shoreward and seaward demonstrate the oscillatory character, caused by interference of the incident and reflected waves in the second-order perturbation theory, while there is no reflection in the linear approximation (first-order perturbation theory). Expressions for wave set-up and set-down along the non-reflecting beach are found and discussed.
Bistable systems with stochastic noise: virtues and limits of effective one-dimensional Langevin equations
Authors: Lucarini V. , Faranda D. , Willeit M.
Published: January 2012

Abstract. The understanding of the statistical properties and of the dynamics of multistable systems is gaining more and more importance in a vast variety of scientific fields. This is especially relevant for the investigation of the tipping points of complex systems. Sometimes, in order to understand the time series of given observables exhibiting bimodal distributions, simple one-dimensional Langevin models are fitted to reproduce the observed statistical properties, and used to investing-ate the projected dynamics of the observable. This is of great relevance for studying potential catastrophic changes in the properties of the underlying system or resonant behaviours like those related to stochastic resonance-like mechanisms. In this paper, we propose a framework for encasing this kind of studies, using simple box models of the oceanic circulation and choosing as observable the strength of the thermohaline circulation. We study the statistical properties of the transitions between the two modes of operation of the thermohaline circulation under symmetric boundary forcings and test their agreement with simplified one-dimensional phenomenological theories. We extend our analysis to include stochastic resonance-like amplification processes. We conclude that fitted one-dimensional Langevin models, when closely scrutinised, may result to be more ad-hoc than they seem, lacking robustness and/or well-posedness. They should be treated with care, more as an empiric descriptive tool than as methodology with predictive power.
Remote sensing of sea ice: advances during the DAMOCLES project
Authors: Heygster G. , Alexandrov V. , Dybkjær G. , Girard-Ardhuin F. , von Hoyningen-Huene W. , Katsev I. L. , Kokhanovsky A. , Lavergne T. , Malinka A. V. , Melsheimer C. , Toudal Pedersen L. , Prikhach A. S. , Saldo R. , Tonboe R. , Wiebe H. , Zege E. P.
Published: January 2012

Abstract. In the Arctic, global warming is particularly pronounced so that we need to monitor its development continuously. On the other hand, the vast and hostile conditions make in situ observation difficult, so that available satellite observations should be exploited in the best possible way to extract geophysical information. Here, we give a résumé of the sea ice remote sensing efforts of the EU project DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies). The monthly variation of the microwave emissivity of first-year and multiyear sea ice has been derived for the frequencies of the microwave imagers like AMSR-E and sounding frequencies of AMSU, and has been used to develop an optimal estimation method to retrieve sea ice and atmospheric parameters simultaneously. A sea ice microwave emissivity model has been used together with a thermodynamic model to establish relations between the emisivities at 6 GHz and 50 GHz. At the latter frequency, the emissivity is needed for assimilation into atmospheric circulation models, but more difficult to observe directly. A method to determine the effective size of the snow grains from observations in the visible range (MODIS) is developed and applied. The bidirectional reflectivity distribution function (BRDF) of snow, which is an essential input parameter to the retrieval, has been measured in situ on Svalbard during the DAMOCLES campaign, and a BRDF model assuming aspherical particles is developed. Sea ice drift and deformation is derived from satellite observations with the scatterometer ASCAT (62.5 km grid spacing), with visible AVHRR observations (20 km), with the synthetic aperture radar sensor ASAR (10 km), and a multi-sensor product (62.5 km) with improved angular resolution (Continuous Maximum Cross Correlation, CMCC method) is presented. CMCC is also used to derive the sea ice deformation, important for formation of sea ice leads (diverging deformation) and pressure ridges (converging). The indirect determination of sea ice thickness from altimeter freeboard data requires knowledge of the ice density and snow load on sea ice. The relation between freeboard and ice thickness is investigated based on the airborne Sever expeditions conducted between 1928 and 1993.
Active Learning in Language Study and Science: Transforming Teacher Practice in North Sumatra’s Elementary Schools
Authors: Djulia Ely , Juwitaningsih Tita , Hamid Abdul , Siallagan Roslin , Gultom Parapat , Hanum Inayah , Anwar Khairul , Lubis Nurul Wardani
Published: January 2012

AbstractAn action research project to investigate the implementation of active learning strategies to improve the quality of teaching and learning was conducted in three government elementary schools (Sekolah Dasar) in North Sumatra that had received training in teaching for active learning under the auspices of the USAID-sponsored project, Decentralized Basic Education 2. Three cycles of data collection utilizing classroom observations, focus group discussions, and participant observation were conducted in each school. Data were analyzed both holistically and categorily to develop a better understanding of teachers’ successes and challenges in teaching for active learning. Finally, an intervention strategy involving modeling of teaching for active learning strategies was designed and implemented by members of the research team in each school. Our results suggest that language and science teachers developed more confidence in utilizing active learning strategies in their classrooms as a result of the intervention. Students also appeared to respond positively to the new active learning teaching strategies employed by their teachers. We conclude that the DBE-2 training provided to these schools can be considered successful; however, more attention needs to be paid to concrete factors that facilitate or impede teaching for active learning in Indonesian elementary schools in order to continue improving the quality of instruction for Indonesian children. Key Words: Islamic Education, Active Learning, Religious Studies, Indonesia
Action Research on the Implementation of Active Learning at an Elementary School in Aceh
Authors: Bahri Ys Syamsul , Mara M. Nasir , Yamin M. , A.B. Suid , Dhin Cut Nya
Published: January 2012

Teachers in the state elementary schools and state Islamic elementary schools of the Indonesian province of Aceh have been trained repeatedly over the past several years on a variety of educational reform initiatives. One of the most important of these has been the effort to promote teaching for active learning in Acehnese schools. Research in other countries, and past experience with teacher training efforts in Aceh, suggest that such a transformation in classroom practice will not be easy. In order to investigate whether and how teachers were transferring their training in active learning into actual classroom practice, a team of lecturers from three universities in Banda Aceh conducted an action research project in one state elementary school. We found that teachers’, principals’, and school supervisors’ understanding of teaching for active learning remained extremely tentative months after receiving training in active learning, and their tentative understanding prevented their active experimentation with what they had learned. A brief retraining session focused on arriving at a common understanding of the concept, committed school leadership, and learning from peers appeared to have a significant impact on teachers’ willingness and ability to try to teach for active learning. Key Words: Active Learning, Action Research, Aceh, Elementary Schools
Action Research on the Implementation of Teaching for Active Learning in Two Elementary Madrasahs in Aceh
Authors: Syah Sulastri Muhammad , Fitri Yulia , Yani Bainuddin , Adlim [None] , Qurnati Tri , Nursalmi [None] , Idris Tasnim , Sabarni [None]
Published: January 2012

Teaching for active learning is an instructional strategy that has been shown to improve student achievement. Many of its advocates also stress its contribution to the development of democratic dispositions in school children. It has, therefore, become a popular reform intended to improve teaching and learning in schools around the world, including Indonesia, where it was a key component of training conducted in Aceh under the auspices of the USAID-funded Decentralized Basic Education 2 Project (DBE2). In order to gauge the extent to which teaching for active learning was being adopted in Aceh, a team of lecturers from Syiah Kuala University and the State Islamic Studies Institute in Banda Aceh conducted an action research project designed to identify the challenges faced by teachers attempting to teach for active learning in two elementary-level madrasahs as well as strategies that might assist them in that effort. The results of our research show that, while the initial training provided to teachers heightened their consciousness of teaching for active learning and inspired some to experiment with the new teaching methodology, teachers’ understanding and acceptance of active learning was still tentative and could be undermined without effective leadership and long term mentoring. Key Words: Active Learning, Teaching, Aceh, Madrasah
Active Learning to Improve Fifth Grade Mathematics Achievement in Banten
Authors: Suherman Andri , Oediyani Soesaptri , Handayani Ika , Uzliawati Lia , Indriana Ina , Nasution Darlaini
Published: January 2012

Teaching for active learning is a pedagogical technique that has been actively promoted in Indonesian education through government reform efforts and international development assistance projects for decades. Recently, elementary schools in Banten province received training in active learning instructional strategies from the USAID-funded project, Decentralized Basic Education 2. Post-training evaluations conducted by lecturers from the University of Sultan Ageng Tirtayasa (UNTIRTA: Universitas Sultan Ageng Tirtayasa) suggested that teachers were successfully employing active learning strategies in some subjects, but not mathematics. In order to understand the difficulties teachers were having in teaching for active learning in mathematics, and to assist them in using active learning strategies, a team of lecturers from UNTIRTA designed and carried out an action research project to train teachers in an elementary school in the city of Cilegon to use a technique called Magic Fingers in teaching Grade 5 multiplication. During the course of the project the research team discovered that teachers were having problems transferring knowledge gained from training in one context and subject to other school subjects and contexts. Key Words: Mathematics, Teaching for Active Learning, Indonesia, Banten
Pediatric Ocular Rosacea: 2 Cases
Authors: Miguel Ana I.M. , Salgado Manuel B. , Lisboa Maria S. , Henriques Filipe , Paiva Maria C. , Castela Guilherme P.L.
Published: January 2012

Purpose

To report the clinical course of 2 pediatric ocular rosacea cases with a significant delay until diagnosis.

Methods

We report 2 interventional case reports. Case 1 is a 10-year-old boy with 2 years of recurrent bilateral blepharitis, repetition chalazion, conjunctival hyperemia, and corneal ulcers, without response to topical antibiotics or topical and systemic steroids. Case 2 is a 9-year-old girl with keratoconjunctivitis and repetition chalazion since she was 2 years old, without improvement after consulting several ophthalmologists and performing several treatments throughout those years.

Results

Rapid response to systemic erythromycin with marked improvement of both cases within a few weeks.

Conclusions

Ocular rosacea is frequently misdiagnosed, particularly in the pediatric population. To our knowledge, this report demonstrates a case with the longest history before diagnosis (7 years) and another case in which a conjunctival biopsy was performed.
Telemedicine and Older Neurology Outpatients: Use of NHS Direct and of the Internet in the UK
Authors: Larner AJ
Published: January 2012

Telemedicine is one potential approach to address the underserviced health needs of older people. This article presents data from a project investigating neurology patients’ awareness and use of the NHS Direct telephone helpline and the Internet over a 10-year period (2001–2010). Older people’s awareness and use of the NHS Direct telephone helpline was low compared to other age groups and did not change with time. Although Internet access and use was also low compared to other age groups, access did increase over time. Hence, future generations of older people may be amenable to health contacts and inputs via cyberspace.
Association Between Vitamin D Dosing Regimen and Fall Prevention in Long-term Care Seniors
Authors: Chua Gilbert T. , Wong Roger Y.
Published: January 2012

IntroductionThe effectiveness of vitamin D in reducing falls among longterm care (LTC) seniors remains nonconclusive. We reviewed how vitamin D dosing regimen could affect rate of fall and number of fallers among LTC seniors.MethodsWe conducted a systematic literature review. Studies were selected by two independent reviewers based on study characteristics (age 75 or older), quality assessment (primary analysis randomized controlled trials), and outcome (rate of fall and number of fallers). Analyses of all trials following trials using daily standard dosage (800–1000 IU) only were performed to compare daily standard dosage with intermittent supratherapeutic dosage in fall prevention.ResultsSeventy-nine studies were identified, with 28 selected by reviewers (kappa 0.98), and four RCT were conducted in LTC. Daily standard dosage provides greater reduction in rate of fall by 16%, which was statistically significant. However, reduction in number of fallers remained statistically insignificant even taking dosing regimen into account.ConclusionsDaily standard dosage of vitamin D has greater benefits in reducing fall rate than that of intermittent supratherapeutic doses, but not in number of fallers. This could imply that vitamin D is useful in preventing fall recurrence rather than first fall. Prospective studies randomizing LTC seniors to different dosing regimens are warranted.
Your Fireplace Reading…
Authors: Madden Ken M.
Published: January 2012

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Moving towards the Age-friendly hospital. A paradigm shift for the hospital-based care of the elderly.
Authors: Huang Allen R , Larente Nadine , Morais Jose Antonio
Published: January 2012

Care of the older adult in the acute care hospital is becoming more challenging. Patients 65-years and older account for 35% of hospital discharges and 45% of hospital days. Up to one-third of the hospitalized frail elderly loses independent functioning in one or more activities of daily living as a result of the ‘hostile environment’ that is present in the acute hospitals. A critical deficit of health care workers with expertise and experience in the care of the elderly also jeopardizes successful care delivery in the acute hospital setting.We propose a paradigm shift in the culture and practice of event-driven acute hospital-based care of the elderly which we call the Age-Friendly Hospital concept. Guiding principles include: a favorable physical environment; zero tolerance for ageism throughout the organization; an integrated process to develop comprehensive services using the geriatric approach; assistance with appropriateness decision-making and fostering links between the hospital and the community.Summary The Age-Friendly Hospital concept we propose may lead the way to enable hospitals in the fast-moving health care system to deliver high quality care without jeopardizing risk-benefit, function, and quality of life balances for the frail elderly.
Effect of Microstructure and Hydrogen Pores on the Mechanical Behavior of an Al7%Si0.3%Mg Alloy Studied by a Combined Phase‐Field and Micromechanical Approach
Authors: Lasko Galina , Apel Markus , Carré Antoine , Weber Ulrich , Schmauder Siegfried
Published: January 2012

A combination of the phase‐field method for the simulation of the microstructure evolution during solidification with subsequent finite element simulation of fracture appearance in the final solidification structure is proposed for the prediction of the mechanical behavior of AlSi based casting alloys, including the effect of solidification porosity caused by hydrogen. Metallographic investigations and computer tomographic observations of the as cast microstructure of an Al7%Si0.3%Mg alloy together with the data obtained from mechanical tensile testing are used to compare and validate the simulation results to demonstrate the capabilities as well as current limitations in micromechanical modeling of void containing materials. In micromechanical simulations with the element elimination technique (EET) it is shown that porosity influences the crack path as well as crack propagation by connecting the pores. In the eutectic microstructure without porosity, failure starts to develop in silicon lamellae and proceeds in the ductile matrix. However, in the presence of pores fracture also initiates in silicon, and in the later stages of loading, porosity affects the path of the crack and results in additional crack nucleation, and thus, these pores also influence crack propagation in the matrix.
Solvus Composition Paths in Multicomponent Alloys—Experimental Approach and Correlation with Calphad Calculations for the Example Al–Mg–Si
Authors: Engelhardt H. , Hallstedt B. , Drüe M. , Löffler A. , Schick M. , Rettenmayr M.
Published: January 2012

An experimental approach employing temperature and concentration gradients is presented that is suitable for determining a sequence of solvus concentrations in a single experimental cycle. The Al–Mg–Si system is used as an example. Al solid solutions (“(Al)”) with different compositions and Mg2Si precipitates were equilibrated in the temperature range between 350 and 550 °C. The equilibrium compositions of (Al) were measured by energy dispersive X‐ray spectroscopy in the transmission electron microscope. The coupled temperature‐concentration values represent a path on the ternary solvus surface. Calphad calculations using different thermodynamic data sets were carried out to relate the experimental results to phase diagram evaluations. The measured solvus path agrees well with solvus data calculated with most recent thermodynamic parameter sets. The experimental approach can be applied to multicomponent alloys irrespective of their number of components with the same experimental effort. The efficiently generated solubility data are suitable to support phase diagram evaluations of multicomponent systems by the Calphad method.
The effect of binary diluents on the performance of ultrahigh molecular weight polyethylene/SiO2 hybrid hollow fiber membrane
Authors: Li Nana , Xiao Changfa , Wang Rui , Zhang Shujie
Published: January 2012

Ultrahigh molecular weight polyethylene (UHMWPE)/SiO2 hybrid hollow fiber membranes were prepared by thermally induced phase separation (TIPS) using mineral oil as the first diluent, polyethylene oxide (PEO) as the second diluent, and SiO2 as additive. The effect of PEO on the rheological behavior, FTIR‐ATR spectra, phase diagram, morphology, and permeability was investigated. The results suggested that a proper amount of PEO can decrease the viscosity of UHMWPE/diluent appropriately. Because PEO and UHMWPE were incompatible, the miscibility of membrane dope could be changed by PEO, which directly affect the phase separation. It was also discovered that a spherulite structure, coming from solid–liquid (S‐L) TIPS, was built at any UHMWPE concentration without PEO. Whereas, an open‐cell porous structure with better connectivity, owing to liquid–liquid (L‐L) phase separation, was produced after adding PEO. The permeability increased firstly, and then decreased because excessive PEO was sensitive for agglomeration. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis, characterization, and amidoximation of diaminomaleodinitrile‐functionalized polyethylene terephthalate grafts for collecting heavy metals from wastewater
Authors: Abdel‐Razik Hamada H. , Kenawy El‐Refaie
Published: January 2012

Synthesis, characterization, and amidoximation of diaminomaleodinitrile‐functionalized polyethylene terephthalate (PET) grafts were studied. Azobisisobutyronitrile (AIBN) was used as an initiator. Optimum conditions for grafting were as follows: monomer concentration [DAMN] = 0.5M, [AIBN] = 1.50 × 10−3 mol/L, T = 80°C and t = 3 h. Water uptake of the grafted‐PET film increased with the increase of grafting yield. The imparted cyano group of the grafted polymer chains (with degree of grafting up to 83%) was converted into amidoxime group by reaction with hydroxylamine. The unique advantage of this polymer is that it contains double amidoxime groups per repeating unit and an additional diethylene spacer unit between neighboring amidoxime groups in each monomeric unit. The grafted‐PET films were characterized by FTIR spectroscopy, differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The grafted‐PET films are more thermally stable than the ungrafted‐PET membrane, since the grafted membrane showed a single degradation pattern despite having two components. A decrease in Tg values is observed as the grafting yield of copolymers increases indicating the incorporation of polydiaminomaleodinitrile chains in amorphous copolymers with higher thermal stability. The prepared amidoximated DAMN83‐g‐PET was investigated for its properties in removing heavy toxic metals, such as Pb2+, Cd2+, Zn2+, Fe2+, Cu2+, Ni2+, Co2+, and Ag1+ from waste water. The amidoximated‐film is characterized by a considerably greater binding ability with respect to heavy metals. The nature of the metal ion also has great importance in the amount binding to the polymeric material. The kinetics of the sorption/desorption process for Co2+, Ni2+, and Zn2+ are investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Properties of the crosslinked plasticized biodegradable poly(vinyl alcohol)/rambutan skin waste flour blends
Authors: Ooi Zhong Xian , Ismail Hanafi , Bakar Azhar Abu , Aziz Noor Aziah Abdul
Published: January 2012

Poly(vinyl alcohol) (PVOH)/rambutan skin waste flour (RWF) crosslinked films were successfully prepared by solution casting with glutaraldehyde (GLU) and hexamethylenetetramine (HMTA) and without crosslinker in the presence of glycerol as a plasticizer. The properties of cast films were evaluated by tensile testing, water absorption, and degradation behavior at different weight ratios of PVOH and RWF. The tensile results show that the PVOH/RWF films crosslinked with HMTA exhibited a slight improvement in the tensile strength and Young's modulus but a lower elongation at break than that of GLU‐crosslinked films; this was attributed to the better crosslinking effect of HMTA, as shown by the Fourier transform infrared results. The HMTA‐crosslinked film showed a lower water absorption and water vapor transmission rate as compared to the GLU‐crosslinked and noncrosslinked films. A natural weathering test revealed that the addition of 1.5 wt % GLU and HMTA did not significantly affect the reduction in tensile properties, but the biodegradability test showed that the weight loss of noncrosslinked films was higher than those of the GLU‐ and HMTA‐crosslinked films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Design and Synthesis of 2‐Iminothiazolidin‐4‐one Moiety‐Containing Compounds as Potent Antiproliferative Agents
Authors: Zhai Xin , Li Wei , Chen Dong , Lai Ruiwei , Liu Jun , Gong Ping
Published: January 2012

A new series of 2,5‐diaryliminothiazolidin‐4‐ones were designed and synthesized as potent antiproliferative agents. The antiproliferative activities of the 25 target compounds were evaluated against three cancer cell lines (A549, H460 and HT29) by MTT assay. Pharmacological data indicated that most of the compounds possessed moderate activity, some showed remarkable activity against one or more cell lines. As the most promising compound,8s(with IC50values of 1.1, 0.01 and 1.3 µM against the A549, H460 and HT29 cell lines) was 1.1‐ to 270‐fold more potent than the reference drug sorafenib. Furthermore, preliminary structure–activity relationships (SARs) were summarized to provide guidance for further design and discovery of 2‐iminothiazolidin‐4‐one‐based antiproliferative agents.
Methylenebisphosphonates with Dienone Pharmacophore: Synthesis, Structure, Antitumor and Fluorescent Properties
Authors: Makarov Mikhail V. , Leonova Evgeniya S. , Rybalkina Ekaterina Yu. , Khrustalev Victor N. , Shepel Nikolay E. , Röschenthaler Gerd‐Volker , Timofeeva Tatiana V. , Odinets Irina L.
Published: January 2012

The synthesis and the antitumor activity and fluorescent properties screening of novel bisphosphonate conjugates with cytotoxic 3,5‐bis((hetero)arylidene)‐4‐piperidone residues were performed. The facile and rapid synthetic route was based on the aza‐Michael addition of NH‐3,5‐bis((hetero)arylidene)‐4‐piperidones to tetraethyl ethylidenebisphosphonate. The synthesized compounds displayed high inhibitory properties towards Caov3, A549, PC3, and KB 3‐1 human carcinoma cell lines. Among those, compounds bearing 4‐cyano‐phenyl and 3‐pyridinyl substituents were revealed as the most active drug candidates with IC50 values in the range of 0.5–2.5 µM. Methylenebisphosphonate with 4‐Me2N‐C6H4 groups in the piperidone framework possessing fluorescence properties may be of interest for visualization of BPs skeletal distribution and cellular uptake in bones and other tissues.
The ability of serum from alpha 1‐antitrypsin–deficient patients to inhibit PRT‐201, a recombinant human type I pancreatic elastase
Authors: Qamar Amir A. , Burke Steven K. , Lafleur Jason D. , Ding Bee C. , Bland Kimberly S. , Wong Marco D. , Gustafson Pamela N. , Blair Andrew T. , Franano F. Nicholas
Published: January 2012

PRT‐201 is a recombinant human pancreatic elastase under development as a treatment for blood vessels to promote hemodialysis access patency. Proteases such as elastase are normally inactivated by antiproteases such as alpha 1‐antitrypsin. It is unknown if serum from patients with alpha 1‐antitrypsin deficiency will inhibit PRT‐201 elastase activity. An assay for PRT‐201 elastase activity in the presence of serum was developed and validated. PRT‐201 elastase activity inhibition curves were developed using serum and also using purified alpha 1‐antitrypsin and alpha 2‐macroglobulin. Serum from 15 patients with documented alpha 1‐antitrypsin deficiency, some of whom were receiving alpha 1‐antitrypsin augmentation therapy, and four normal volunteers was analyzed. Serum from normal volunteers and patients with alpha 1‐antitrypsin deficiency completely inactivated PRT‐201 elastase activity in vitro. In the alpha 1‐antitrypsin–deficient patients, the volume of serum necessary to inhibit elastase activity was related to the serum concentration of alpha 1‐antitrypsin and augmentation therapy. Purified alpha 1‐antitrypsin and alpha 2‐macroglobulin were each alone capable of completely inhibiting PRT‐201 elastase activity. It is unlikely that the use of PRT‐201 will be associated with negative outcomes in patients with alpha 1‐antitrypsin deficiency.
Untersuchungen zur Biegetragfähigkeit von verzahnten Balken
Authors: Rug Wolfgang , Thoms Frank , Grimm Uwe , Eichbaum Guido , Abel Stephan
Published: January 2012

Die Verzahnung ist eine historische Verbindungstechnik, um einzelne Balken schubfest über ihre Längsseite zu einem Träger zu verbinden. Diese Zahnbalken treten heute nur noch im Zuge von Erhaltungsarbeiten an alten Gebäuden in Erscheinung. Aus denkmalpflegerischen Gründen sollen derartige Konstruktionen immer öfter substanzschonend erhalten, repariert oder instandgesetzt werden.

In der modernen Holzbauliteratur fehlen allerdings Angaben zu Entwurf, Herstellung und Berechnung der verzahnten Balken. Regeln zur statischen Berechnung und Konstruktion derartiger Träger finden sich in der Holzbauliteratur im Zeitraum zwischen 1830 und 1970.

Flexural load‐bearing capacity of composite beams with teeth joints.

The dovetail connection is a historical joining technology to avoid thrust by joining scantlings to beams. Nowadays those beams are only appearing during renovations of historical buildings. By preservations of monuments and historical buildings these old joinings should be repaired or restored.

There are no codes of practice to these special composite beams in modern literature of timber work. Rules for static calculations are recorded in timber work literature in the period between 1830 to 1970.
Untersuchungen an traditionellen Holzverbindungen – Der abgestirnte Zapfen
Authors: Koch Heiko , Seim Werner
Published: January 2012

Traditionelle Holzverbindungen mit abgestirnten Zapfen finden sich häufig bei historischen Holztragwerken zur Verbindung zweier schräg aufeinandertreffender Stäbe, wenn Druckkräfte zu übertragen sind. Bei einer Umnutzung oder bei Schäden wird ein Tragsicherheitsnachweis für diese Verbindungen erforderlich. Um das Tragverhalten dieser Verbindungen besser abschätzen zu können, wurden experimentelle Untersuchungen an Verbindungen mit abgestirnten Zapfen durchgeführt. Ausgehend von diesen Untersuchungen wurde ein Modell entwickelt, mit dem die Tragfähigkeit dieser Verbindungen berechnet werden kann. Dabei werden verschiedene Bruchmechanismen – Abscheren der Lamellen (Rollschubversagen), Versagen der Stirn‐ und Grundfläche – betrachtet, wobei der Einfluss der Reibung in den Kontaktflächen berücksichtigt wurde. Aufgrund der guten Übereinstimmung der Versuchsergebnisse mit den mithilfe des Modells ermittelten Tragfähigkeiten kann das Modell für die Bemessung von Verbindungen mit abgestirnten Zapfen vorgeschlagen werden. Die relevanten Bemessungsschritte werden dargestellt und an einem Beispiel erläutert.

Investigation on traditional carpentry joints – The tapered tenon.

Traditional carpentry joints with tapered tenons had been used widely in traditional timber structures in middle Europe to connect two structural parts under compression loads, that concur in a somehow diagonal angle. When a change of use is required or when damages are obviously, then an analytical model is needed to prove the structural safety. Experimental investigations were accomplished and an analytical model was developed for this type of joinery. Three types of failure were considered – rolling shear failure, failure of the front side and failure of the bottom face. The influence of friction was observed and determined. Because of the good accordance of the experimental and the analytical results it can be recommended to use the model for structural calculations on tapered tenon joints. The design‐steps are documented and explained. A practical example for the calculation is given.
Verbundfassade aus Upcycling‐PUR‐Pressplatten und Holz für einen Lehr‐ und Forschungspavillon in Berlin
Authors: Schmid Volker , Zauft Doreen
Published: January 2012

Die nachhaltige Kombination neuer Materialien und die Demonstration neuer technischer und architektonischer Möglichkeiten war das Ziel eines kombinierten Forschungs‐ und Lehrprojekts an der Technischen Universität Berlin. Anhand eines von Studierenden entworfenen und gebauten Pavillons wurde eine neuartige Verbundfassade erprobt und umgesetzt. Die Haut der Fassade des kleinen Holztafelbaus besteht aus Upcycling‐Polyurethan‐Pressplatten, die mit einer 2 bis 3 mm dicken, hochelastischen Polyurethan‐Beschichtung versehen sind. Der Pavillon wird als Veranstaltungsort und Studentencafe genutzt und dient den Forschern gleichzeitig zur Evaluation des neuen Fassadensystems über die kommenden Jahre.

Education and research – Composite system of up‐cycled PUR panels and timber for façade structures.

The environmentally friendly combination of new materials and the demonstration of new engineering and architectural possibilities is the goal of a project at the “Department of Conceptual and Structural Design‐Composite Structures”. An experimental pavilion with a novel composite façade is designed, aiming to improve the durability of timber structures by employing technical and environmental innovations. Therefore a timber frame is combined with up‐cycled compressed polyurethane (PUR) panels which again are protected by a 2 to 3 mm thick sprayed polyurethane coating. The pavilion is used for lectures during summertime and at the same time allows researchers to evaluate its innovative façade structure during the coming years.
Bewehrungs‐ und Konstruktionsregeln des Stahlbetonbaus im Wandel der Zeit
Authors: Stauder Florian , Wolbring Michael , Schnell Jürgen
Published: January 2012

Bauen im Bestand stellt für alle Beteiligten eine große Herausforderung dar, da wesentliche Merkmale eines Bestandstragwerkes in der Regel unbekannt sind. Neben fehlenden Angaben bezüglich der Eigenschaften der verwendeten Materialien liegen oftmals nur wenige Informationen zur Art der konstruktiven Durchbildung der Bauteile vor. In diesem Beitrag werden Hinweise zur historischen Entwicklung wesentlicher Bewehrungs‐ und Konstruktionsregeln in Deutschland gegeben. Der Überblick soll helfen, bereits durch die Zuordnung von Bestandstragwerken zu einer bestimmten Normengeneration potenzielle Defizite hinsichtlich der Bewehrungsführung identifizieren zu können.

Due to the reason that the main characteristics of an existing building are normally not known, the design and construction of these structures is a challenge for all participants. Besides the fact that the properties of the used materials are not known, there is only little information about the detailing of the structural members available. In this paper, reference is given to the historical development of the essential reinforcement and construction rules in Germany. This overview is aimed to help identifying potential shortcomings of the configuration of the reinforcement by relating an existing structure to a particular standard generation.
Begrenzung der Biegeschlankheit nach Eurocode 2
Authors: Göttlich Peter
Published: January 2012

Durchbiegungen in Stahlbetontragwerken müssen bereits im Rahmen des Entwurfes ausreichend begrenzt werden. Der Eurocode 2, der im Jahr 2012 bauaufsichtlich eingeführt wird, gibt hierzu neue Regeln vor, die im Ergebnis deutlich schärfer sind als diejenigen der DIN 1045 (Ausgabe 1988 und aktuelle Ausgabe 2008).

Die Regeln des EC2 sind ihrer Natur nach jedoch keine Entwurfsgleichungen, mit denen die Bauteildicken direkt bestimmt werden können, sondern eher zur abschließenden Kontrolle des Entwurfes geeignet. Auf der Grundlage der Nachweisgleichungen des EC2 wurden daher Diagramme als direkte Bemessungshilfe entwickelt, die ein iteratives Vorgehen weitestgehend vermeiden und Architekten und Ingenieuren die Entwurfsarbeit deutlich erleichtern sollen.

Limitation of span to depth ratio (slenderness) according to Eurocode 2

Deflections in reinforced concrete frames must already be sufficiently limited during design. The Eurocode 2, which will be implemented in 2012 in Germany, provides new rules, which are clearly more demanding than those of the DIN 1045 (issue 1988 and current issue 2008).The rules in EC2 are however, by their nature, not design equations from which the member dimensions can be directly determined. Therefore they are normally used for final verification of the design. To overcome this, design graphs, based on the design equations of EC2, have been prepared. These are meant to significantly help architects and engineers in the early stages of design by avoiding an iterative procedure as far as possible.
Experimentelle und numerische Untersuchungen zum Beulen von dünnen Scheiben aus UHPFRC unter Druckbeanspruchung
Authors: Escobar‐Castillo Martha Nerida , Freytag Bernhard , Linder Josef , Sparowitz Lutz
Published: January 2012

Ultrahochfester faserbewehrter Beton (UHPFRC) ermöglicht das Bauen mit äußerst dünnwandigen Elementen, die sowohl in der Architektur als auch im Konstruktiven Ingenieurbau viele Vorteile mit sich bringen. Die Schlankheit derartiger Bauteile übersteigt den gewohnten Bereich. Dies führt zu stark erhöhter Beulgefahr, weshalb neue Bemessungsregeln erarbeitet werden müssen. Der hier vorgestellte Beitrag zielt darauf ab, die grundsätzlichen Zusammenhänge im Tragverhalten von dünnwandigen UHPFRC‐Scheiben unter Druckbeanspruchung systematisch darzustellen, um eine Grundlage für die Ableitung geeigneter Ansätze für Berechnungsmodelle zu erhalten. Im Mittelpunkt der Arbeit stehen umfangreiche, experimentelle Untersuchungen, die einen großen Schlankheitsbereich abdecken. Um verlässliche Traglastergebnisse zu bekommen, wird eine spezielle Regelungstechnik entwickelt, mit der das an sich plötzlich eintretende Stabilitätsversagen so langsam abläuft, dass es sowohl messtechnisch als auch visuell über die Traglast hinaus erfasst werden kann. Für die Erleichterung der Auswertung und der Ergebnisinterpretation werden die Versuche mit detaillierten FE‐Simulationen untermauert und ergänzt.

Experimental and Numerical Investigation on Compressive Buckling of Thin Panels Made of UHPFRC

Fibre reinforced ultra high performance concrete allows for thin‐walled construction elements which provide aesthetic as well as structural advantages. Compared to conventional reinforced concrete walls the slenderness of such plates will grow significantly and as a consequence the buckling failure will become more relevant. Thus, new rules for its structural design have to be developed. This paper aims at the fundamental understanding of the load carrying behaviour of thin‐walled UHPFRC panels under compression in order to show adequate ways for deriving calculation models. The main item of the work are buckling experiments covering a wide range of slenderness. The test setup as well as the loading control are designed in a way that abrupt collapse is avoided, which leads to absolutely reliable results of the ultimate load. Extensive and sophisticated numerical investigation complete the measurements and makes interpretation easier.
Verbundverhalten von vorgespannten Litzen in UHPC
Authors: Bertram Guido , Hegger Josef
Published: January 2012

Ultrahochfester Beton (UHPC = Ultra‐High Performance Concrete) ist hervorragend geeignet für vorgespannte Bauteile. Um eine sichere und dennoch wirtschaftliche Bemessung von vorgespannten Trägern mit sofortigem Verbund vornehmen zu können, muss das Verankerungsverhalten der Litzen bekannt sein. Die hohen Verbundfestigkeiten führen zu kurzen Übertragungslängen und verbessern dadurch die Querkrafttragfähigkeit. Der vorliegende Beitrag stellt ein Verbundmodell zur Ermittlung der Übertragungslänge bei UHPC vor. Das Modell baut auf den experimentellen Ergebnissen aus auf.

Bond Behavior of prestressed Strands in UHPC. Part 2: Bond model derivation for the calculation of transfer lengths

Ultra‐High Performance Concrete (UHPC) is an appropriate construction material for pretensioned girders. To ensure an economic but safe design a detailed knowledge of the behavior of pretensioned strands in the anchorage zone is essential. The dimension of the bond anchorage zone favors the cost‐effective design of pretensioned girders, especially when the shear resistance is decisive. In this article a bond model is derived to calculate the transfer length. The model bases on the experimental results in.