bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Cast Films of Bovine Mucin and Prosopis Gum Containing a CicatrinÂ® Powder on Wound Healing
Authors: Momoh MA , Adikwu MU , Eraga SO
Published: October 2008

Orodispersible tablets of carbamazepine were prepared with a view to enhance patient compliance by direct compression method using 3Â² full factorial design. Crospovidone (2-10% w/w) was used as superdisintegrant and microcrystallinecellulose (0-30% w/w) was used as diluent, along with directly compressible mannitol to enhance mouth feel. The tablets were evaluated for hardness, friability, thickness, drug content uniformity, in vitro dispersion time, wetting time and water absorption ratio. Based on in vitro dispersion time (approximately 10 s); the formulation containing 2% w/w crospovidone and 30%w/w microcrystallinecellulose was found to be promising and tested for in vitro drug release pattern (in pH 6.8 phosphate buffer), short-term stability (at 40Âº/75 % RH for 3 w) and drug-excipient interaction. This formulation showed four-fold faster drug release (t25%) compared to the conventional commercial tablet formulation. Short-term stability studies on the formulation indicated that there are no significant changes in drug content and in vitro dispersion time (p < 0.05). Â Key words: mucin, Prosopis gum, cicatrin, healingDOI = 10.3329/dujps.v7i1.1200Dhaka Univ. J. Pharm. Sci. 7(1): 7-10, 2008 (June)
Antimicrobial Activity of Some Indigenous Plants of Bangladesh
Authors: Rahman Mohammad S , Rahman Mohammed Z , Wahab Md Abdul , Chowdhury Rasheduzzaman , Rashid Mohammad A
Published: October 2008

The antimicrobial activity of methanol extracts of 17 plant species of Bangladesh was evaluated by the agar disc diffusion method. Among those, eight plant extracts exhibited potent antimicrobial activity against a wide variety of Gram positive and Gram negative bacteria and fungi at a concentration of 400 Î¼g /disc.Key words: Antimicrobial activity, Disc diffusion method.DOI = 10.3329/dujps.v7i1.1213Dhaka Univ. J. Pharm. Sci. 7(1): 23-26, 2008 (June)
Evaluation of Dissolution Behavior of Paracetamol Suspensions
Authors: Azam Md Golam , Haider Syed Shabbir
Published: October 2008

Ten brands of commercial paracetamol suspensions were investigated for their dissolution characteristics in 0.1 N HCl at a speed of 25 rpm using USP dissolution test apparatus II (Paddle method). It was observed that differences exist among the rate of paracetamol dissolution from the samples, particularly at the early stages. For nine of the brands, paracetamol dissolution varied between 72% and 100% at 15 minutes. One of the samples showed a very unsatisfactory rate and extent of drug dissolution as only 39% and 52% paracetamol was released after 15 and 30 minutes respectively. The effect of two commonly used suspending agents, CMC-Na and Avicel, on the release of paracetamol was studied using four laboratory-made suspensions. Retarded drug dissolution was observed which was related to the concentration of the suspending agents. Drug release kinetics followed first order as well Higuchi models. Viscosity of the samples and initial drug release was found to be inversely correlated (R2=0.9081 at 3 minutes) which faded away with the lapse of time. Key words: Paracetamol suspension, in vitro dissolution, suspending agents Â Â DOI = 10.3329/dujps.v7i1.1218 Dhaka Univ. J. Pharm. Sci. 7(1): 53-58, 2008 (June)
Development of Indomethacin Sustained Release Microcapsules using Ethyl Cellulose and Hydroxy Propyl Methyl Cellulose Phthalate by O/W Emulsification
Authors: Kamal Md Abu Hena Mostafa , Ahmed Maruf , Wahed Mir Imam Ibne , Amran Md Shah , Shaheen Sharif Md , Rashid Manunur , Anwar-Ul-Islam Md
Published: October 2008

Indomethacin (IM) sustained release microcapsules were successfully prepared using ethyl cellulose (EC) and hydroxy propyl methyl cellulose phthalate (HPMCP) by o/w emulsification-solvent evaporation technique. The prepared microcapsules were evaluated for size, shape, drug content and in vitro drug release. The microcapsules show sustained release curves at pH 7.2 phosphate buffer for up to 6 h. The data obtained from the dissolution profiles were compared in the light of different kinetics models and the regression coefficients were compared. The in vitro dissolution study confirmed the Higuchi-order release pattern. Particle size and release data analysis from five consecutive batches prepared in the laboratory indicated suitable reproducibility of the solvent evaporation process. The release rate increased exponentially with the addition of HPMCP in EC. IM release rate was observed highest with the highest concentration of HPMCP (3:7 ratio of EC:HPMCP), used in the present studies. On the other hand, IM release rate was lowest when EC and HPMCP combination was used at the ratio of 10:0. When percent of HPMCP was increased, the particle size of microcapsules was decreased. Key words: Indomethacin, sustained release, microcapsule, HPMCP, EC, Higuchi-order Â DOI = 10.3329/dujps.v7i1.1223 Dhaka Univ. J. Pharm. Sci. 7(1): 83-88, 2008 (June)
Crime Scene Reconstruction Using a Fully Geomatic Approach
Authors: Agosto Eros , Ajmar Andrea , Boccardo Piero , Giulio Tonolo Fabio , Lingua Andrea
Published: October 2008

This paper is focused on two main topics: crime scene reconstruction, based on a geomatic approach, and crime scene analysis, through GIS based procedures. According to the experience of the authors in performing forensic analysis for real cases, the aforesaid topics will be examined with the specific goal of verifying the relationship of human walk paths at a crime scene with blood patterns on the floor. In order to perform such analyses, the availability of pictures taken by first aiders is mandatory, since they provide information about the crime scene before items are moved or interfered with. Generally, those pictures are affected by large geometric distortions, thus - after a brief description of the geomatic techniques suitable for the acquisition of reference data (total station surveying, photogrammetry and laser scanning) - it will be shown the developed methodology, based on photogrammetric algorithms, aimed at calibrating, georeferencing and mosaicking the available images acquired on the scene. The crime scene analysis is based on a collection of GIS functionalities for simulating human walk movements and creating a statistically significant sample. The developed GIS software component will be described in detail, showing how the analysis of this statistical sample of simulated human walks allows to rigorously define the probability of performing a certain walk path without touching the bloodstains on the floor.
First Contact to Odors: Our Current Knowledge about Odorant Receptor
Authors: Song Hyoung-Gon , Young Kwon Jae , Soo Han Hyung , Bae Yong-Chul , Moon Cheil
Published: October 2008

Chemical senses – especially smell – are known to be important for the fundamental life events such as sensing predators, selecting mates, as well as finding food. The chemical senses are decoded in the olfactory system which is able to detect and differentiate thousands of odorous substances comprised of chemically divergent structures (i.e. odorants). The high selectivity of the olfactory system is heavily dependent on the receptors for each odorants (i.e. odorant receptors). Thus, studying odorant receptors may not only facilitate our understanding the initial events of olfaction but provide crucial knowledge for developing a novel, odorant receptor-based biosensor for chemical screening. Here we provide a review of recent advances in our understanding of odorant receptors.
SIMULATION MODEL FOR SUPPLY CHAIN RELIABILITY EVALUATION / TIEKIMO GRANDINĖS PATIKIMUMO ĮVERTINIMO IMITACINIS MODELIS
Authors: Klimov Ruslan , Merkuryev Yuri
Published: October 2008

This paper investigates problems related to supply chain risk identification and simulation‐ based risk evaluation. Accordingly, the paper is divided into two logical parts. The first part represents earlier researches about risk recognition within the sphere of supply chains. The distinction between terms “uncertainty” and “risk” is discussed. Based on the predefined supply chain functions, additional risks connected with supply chain reliability are recognized. Then, a conception of simulation‐based risk evaluation approach is discussed. Within the second part of the paper, a numerical example is provided, within which a simplified supply chain system is defined and corresponding risk evaluation is performed.

Santrauka

Šiame straipsnyje nagrinėjamos problemos, susijusios su tiekimo grandinės rizikos identifikavimu ir modeliavimu pagrįstu rizikos įvertinimu. Straipsnis suskaidytas į dvi logines dalis. Pirmojoje dalyje aprašomi ankstesni tiekimo grandinėse slypinčių rizikų tyrimai. Aptariami terminų neapibrėžtumas ir rizika skirtumai. Remiantis pasirinktomis tiekimo grandinės funkcijomis, nustatytos naujos rizikos, kurios veikia tiekimo grandinės patikimumą. Toliau aptariama modeliavimu pagrįsta rizikos įvertinimo koncepcija. Antroje straipsnio dalyje pateiktas skaitmeninis pavyzdys, kuriame sudaroma supaprastinta tiekimo grandinės sistema ir įvertinama su ja susijusi rizika.
MULTI‐ATTRIBUTE ANALYSIS OF INVESTMENTS RISK ALTERNATIVES IN CONSTRUCTION / STATYBOS ALTERNATYVŲ INVESTICINĖS RIZIKOS DAUGIATIKSLĖ ANALIZĖ TAIKANT SAW IR CLARA METODUS
Authors: Shevchenko Galina , Ustinovichius Leonas , Andruškevičius Algirdas
Published: October 2008

In project development it is hardly possible to get exhaustive and accurate information. As a result, the situations occur, the consequences of which can be very damaging to the project. Inaccurate evaluation of the strategy related to capital investment and project implementation is one of the reasons why such estimates are not required in practice. Instead, a classification approaches may be used for this purpose. The decision‐making process, based on the established risk assessment principles expressed in linguistic terms, requires qualitative judgement and experiential knowledge of the construction experts. Presented structured and realistic methods deals systematically with different risk management situations and assist the investors in reaching the correct risk assessment of possible alternatives will be of great value. This paper presents a methods of multiattribute comparativite analysis (CLARA and SAW methods) of variants of investment classified risks in construction. A practical case to illustrate how the methods works is presented. Santrauka Šiame straipsnyje nagrinėjamos daugiatikslės analizės metodų taikymo galimybės. Svarbus investicijų efektyvumo garantas yra nuodugni investicinių projektų analizė ir vertinimas. Tai leidžia pagal tam tikrus kriterijus nustatyti investavimo variantų efektyvumą. Vertinimo kriterijai turi būti grindžiami tiek investicinį projektą įgyvendinančio subjekto, tiek investuotojo interesais. Analizuojant investicinius procesus yra susiduriama su įvairaus pobūdžio informacija – kokybinė ir kiekybinę. Šiame straipsnyje yra siūlomi du metodai, analizuojantys (įvertinantys) investicinę riziką – SAW ir CLARA metodai. Pateikti metodų pritaikymo rezultatai.
Tunable Adhesive Superhydrophobic Surfaces for Superparamagnetic Microdroplets
Authors: Cheng Zhongjun , Feng Lin , Jiang Lei
Published: October 2008

Inspired by the gecko's ability to reversibly stick and unstick to a variety of solid surfaces during locomotion, a new superhydrophobic iron surface that has a tunable adhesive force with the superparamagnetic microdroplet as a function of the magnetic field was fabricated by a simple and inexpensive method. The as‐prepared surface is low adhesive, and a superparamagnetic microdroplet can roll easily on the surface. After the surface is magnetized, it becomes highly adhesive, which can pin a superparamagnetic microdroplet. Further demagnetizing the surface that has been magnetized, a superparamagnetic microdroplet can roll on the surface again, indicating that the surface returns to its initial low adhesive state. Reversible transition between the high adhesive pinning state and low adhesive rolling state can be achieved by simply magnetizing and demagnetizing the surface alternately. The tunable effect maybe attribute to the cooperation of the soft ferromagnetic property of iron plate and the microstructure on the surface. Such intelligent surface could potentially be used in a wide range of applications such as biochemical separation, no‐loss transport of microdroplet, and in situ detection.
Microtexture and Chitin/Calcite Orientation Relationship in the Mineralized Exoskeleton of the American Lobster
Authors: Al‐Sawalmih Ali , Li Chenghao , Siegel Stefan , Fabritius Helge , Yi Sangbong , Raabe Dierk , Fratzl Peter , Paris Oskar
Published: October 2008

The exoskeleton of the American lobster Homarus americanus is a hierarchical nanocomposite consisting of chitin–protein fibers, reinforced with amorphous calcium carbonate (ACC) and a small amount of crystalline calcite. Crystallographic pole‐figure analysis reveals two texture components of the crystalline α‐chitin in the exoskeleton. One component represents the well‐known twisted plywood structure of chitin–protein fibers within the cuticle plane, and the second component represents fibers oriented roughly perpendicular to the cuticle surface. These perpendicular fibers interpenetrate the open canals of the planar honeycomblike structure originating from the well‐developed pore‐canal system present in this material. The calcite crystallites reveal fiber texture with the crystallographic c‐axis oriented perpendicular to the cuticle surface, suggesting an orientation relationship between calcite and the organic chitin–protein fibers. Local orientation analysis using X‐ray microdiffraction reveals that the crystalline calcium carbonate fraction is associated with the chitin–protein fibers oriented perpendicular to the surface. Calcite is exclusively found in the exocuticle and is mostly restricted to a thin layer in the outermost region, while the major part of the exocuticle and the whole endocuticle contain ACC exclusively. It is therefore speculated that the most likely function of calcite in the exoskeleton of the American lobster is related to impact‐ and wear‐resistance.
Nanoporous Organosilicate Films Prepared in Acidic Conditions Using Tetraalkylammonium Bromide Porogens
Authors: Eslava Salvador , Baklanov Mikhail R. , Urrutia Jone , Kirschhock Christine E. A. , Maex Karen , Martens Johan A.
Published: October 2008

Organosilicate films with narrow pore size distribution tunable in the range of 1–3.4 nm were prepared by spin‐coating of silicon wafers with sols prepared in acidic conditions using tetraethyl orthosilicate, methyltrimethoxysilane, and tetraalkylammonium bromide (TAABr) porogen. The pore size was defined by the alkyl chain length of the quaternary ammonium molecule and the porogen concentration. The pore network in the films and the hydrophobicity of the pore surfaces were characterized using ellipsometric porosimetry with toluene and water adsorbates. In the absence of TAABr, the pore volume was 9 vol% and the pore size 1 nm. By using TAABr porogens, monomodal pore size distributions were obtained in the range of 1.2–3.5 nm. The pore volume was in the range from 18 vol% at 1.2 nm pore diameter up to 54 vol% at 3.5 nm diameter. The hydrophobicity of the pores was dependent on the pore diameter, with smaller pores being the least hydrophobic. The increase of hydrophobicity with pore size was explained by an increased distance between silanol groups on the curved pore surfaces. The mechanical properties and dielectric constant of these films were comparable to reference materials prepared using more sophisticated porogens reported in the literature.
Laterally Ordered Bulk Heterojunction of Conjugated Polymers: Nanoskiving a Jelly Roll
Authors: Lipomi Darren J. , Chiechi Ryan C. , Reus William F. , Whitesides George M.
Published: October 2008

This paper describes the fabrication of a nanostructured heterojunction of two conjugated polymers by a three‐step process: i) spin‐coating a multilayered film of the two polymers, ii) rolling the film into a cylinder (a “jelly roll”) and iii) sectioning the film perpendicular to the axis of the roll with an ultramicrotome (nanoskiving). The conjugated polymers are poly(benzimidazobenzophenanthroline ladder) (BBL, n‐type) and poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene) (MEH‐PPV, p‐type). The procedure produces sections with an interdigitated junction of the two polymers. The spacing between the phases is determined by spin‐coating (∼15 nm to 100 nm) and the thickness of each section is determined by the ultramicrotome (100 to 1000 nm). The minimum width of the MEH‐PPV layers accessible with this technique (∼15 nm) is close to reported exciton diffusion lengths for the polymer. When placed in a junction between two electrodes with asymmetric work functions (tin‐doped indium oxide (ITO) coated with poly(3,4‐ethylenedioxythiophene:poly(styrenesulfonate) (PEDOT:PSS), and eutectic gallium‐indium, EGaIn) the heterostructures exhibit a photovoltaic response under white light, although the efficiency of conversion of optical to electrical energy is low. Selective excitation of BBL with red light confirms that the photovoltaic effect is the result of photoinduced charge transfer between BBL and MEH‐PPV.
Reusable Cobalt(III)‐Salen Complex Supported on Activated Carbon as an Efficient Heterogeneous Catalyst for Synthesis of 2‐Arylbenzimidazole Derivatives
Authors: Sharghi Hashem , Aberi Mahdi , Doroodmand Mohammad Mahdi
Published: October 2008

Various 2‐arylbenzimidazoles were synthesized from phenylenediamines and aromatic aldehydes via a one‐step process in the presence of a catalytic amount of a cobalt‐salen complex supported on activated carbon [CoxO‐Co(salen) 11] at room temperature. The salient features of this method include mild conditions, short reaction times, high yields, easy purification, recyclable catalyst, large‐scale synthesis and simple procedure. The reactions were performed in ethanol and the catalyst could be reused for several cycles without a decrease in activity. The heterogeneous catalyst was characterized by powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), atomic forced microscopy (AFM), thermogravimetric (TG) methods for analysis of nitrogen adsorption and FT‐IR spectroscopy. Leaching experiments showed that the catalyst is most strongly anchored to the activated support after 10 cycles of reuse.
Efficient and Versatile Sol‐Gel Immobilized Copper Catalyst for Ullmann Arylation of Phenols
Authors: Benyahya Sofia , Monnier Florian , Taillefer Marc , Man Michel Wong Chi , Bied Catherine , Ouazzani Fouad
Published: October 2008

A new hybrid silica with urea‐based bipyridyl bridging units has been synthesized by a sol‐gel process. The copper‐complexed hybrid silica is an efficient heterogeneous catalyst for the Ullmann coupling of aryl halides with phenols. It is easily withdrawn and recovered from the reaction media by filtration. It is also a versatile catalyst for subsequent reactions with several substrates yielding products with the same efficiency even after ten re‐uses and with minimal leaching. This is the first example of the use of a copper‐complexed bridged silsesquioxane for the preparation of a recoverable catalyst in modern Ullmann chemistry. This may represent a promising route to the reduction of waste while maintaining economic viability.
Diazo Reagents in Copper(I)‐Catalyzed Olefination of Aldehydes
Authors: Lebel Hélène , Davi Michaël
Published: October 2008

The olefination of aldehydes to synthesize unsaturated ketones, esters, amides and phosphonates using diazo reagents and triphenylphosphine in the presence of copper(I) iodide as catalyst, is described. Good to excellent E:Z selectivities as well as yields were obtained for a large variety of aliphatic, aromatic and heteroaromatic aldehydes. The reaction showed also an excellent functional group compatibility and aldehydes were selectively reacted in the presence of ketone, nitro, amine, ether, acetal, thioether and halide groups. The use of a cost‐effective copper salt as a catalyst is advantageous compared to previously reported expensive transition metal complexes. The method was used in the total synthesis of the scutifoliamide A, a biologically active compound that exhibits antifungal activity.
Efficient Synthesis of γ,δ‐Alkynyl‐β‐amino Acid Derivatives by a New Copper‐Catalyzed Amine‐Alkyne‐Alkyne Addition Reaction
Authors: Zhou Lei , Jiang Huan‐feng , Li Chao‐Jun
Published: October 2008

A simple and efficient method for the synthesis of γ,δ‐alkynyl‐β‐amino acid derivatives by a new copper‐catalyzed amines‐alkynes‐alkynes addition was developed. Various γ,δ‐alkynyl‐β‐amino acid derivatives were obtained in moderate to good yields in one step.
Exponential observers for distributed tubular (bio)reactors
Authors: García Míriam R. , Vilas Carlos , Banga Julio R. , Alonso Antonio A.
Published: October 2008

The dissipative nature of spatially distributed process systems is exploited to develop efficient exponential state observers based on a low‐dimensional dynamic representation of the original set of partial differential equations. The suggested approach combines standard observer design techniques for reactors, where the reaction rates are unknown with efficient model reduction methodologies based on projection of the original concentration and temperature fields on low‐dimensional subspaces capturing the slow dynamics of the process. The global exponential stability of the resulting observer is derived combining classical Lyapunov analysis with a transformation that allows us to obtain a diffusion system from a diffusion‐convection system. In addition, aspects related to the location of sensors and their influence on the ability to reconstruct the necessary fields to feed the observer will also be considered. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Der seltsame Fall des Botulinum‐Neurotoxins: chemische und biologische Modulierung des tödlichsten aller Gifte
Authors: Willis Bert , Eubanks Lisa M. , Dickerson Tobin J. , Janda Kim D.
Published: October 2008

In seiner klassischen Erzählung “Der Seltsame Fall des Dr. Jekyll und Mr. Hide” beschreibt Robert Louis Stevenson einen gespaltenen Menschen zwischen Gut und Böse. Botulinum‐Neurotoxin (BoNT), der wirksamste bekannte Giftstoff, ist von ähnlich zwiespältiger Natur: BoNT zeigt einerseits eine ausgeprägte Morbidität und Mortalität, kommt andererseits aber – wenn auch in viel geringeren Dosen – in einem breiten Spektrum klinischer Szenarien zum Einsatz. In jüngerer Zeit sind enorme Fortschritte beim Verständnis der Struktur und Funktion von BoNT erzielt worden, die eine intensive Erforschung von biomakromolekularen und niedermolekularen Modulatoren der BoNT‐Aktivität nach sich zogen. Ein Schwerpunkt dieser Projekte lag auf der Identifizierung von Inhibitoren, die einer BoNT‐Exposition, z. B. im Falle eines bioterroristischen Anschlags, entgegenwirken können. Dieser Aufsatz fasst die aktuellen Fortschritte bei der Entwicklung von Therapeutika zur Prävention und Behandlung von Botulismus zusammen, mit einem Schwerpunkt auf Impfstoffen sowie peptidischen und niedermolekularen Inhibitoren.
The Strange Case of the Botulinum Neurotoxin: Using Chemistry and Biology to Modulate the Most Deadly Poison
Authors: Willis Bert , Eubanks Lisa M. , Dickerson Tobin J. , Janda Kim D.
Published: October 2008

In the classic novella “The Strange Case of Dr. Jekyll and Mr. Hyde”, Robert Louis Stevenson paints a stark picture of the duality of good and evil within a single man. Botulinum neurotoxin (BoNT), the most potent known toxin, possesses an analogous dichotomous nature: It shows a pronounced morbidity and mortality, but it is used with great effect in much lower doses in a wide range of clinical scenarios. Recently, tremendous strides have been made in the basic understanding of the structure and function of BoNT, which have translated into widespread efforts towards the discovery of biomacromolecules and small molecules that specifically modulate BoNT activity. Particular emphasis has been placed on the identification of inhibitors that can counteract BoNT exposure in the event of a bioterrorist attack. This Review summarizes the current advances in the development of therapeutics, including vaccines, peptides, and small‐molecule inhibitors, for the prevention and treatment of botulism.
Detecting changes in simulated events using partial‐interval recording and momentary time sampling
Authors: Rapp John T. , Colby‐Dirksen Amanda M. , Michalski Dara N. , Carroll Regina A. , Lindenberg Ally M.
Published: October 2008

In a series of three studies, we evaluated simulated data with reversal designs to determine whether partial‐interval recording (PIR) and momentary time sampling (MTS) detected changes that were evident with continuous measures. The results from Study 1 showed that MTS with interval sizes up to 30 s detected most of the moderate and large changes in duration events and MTS with interval sizes up to 1 min detected most large changes in duration events. By comparison, PIR with 10‐s intervals detected approximately half of all changes in duration events. The results of Study 2 showed that only 10‐s PIR reliably detected most small, moderate, and large changes in frequency events. The results of Study 3 showed that PIR with 10‐s intervals generated a relatively high percentage of false positives for duration events, whereas MTS did not. As a whole, the results support previous findings, but also provide new guidelines for the use of PIR and MTS. Copyright © 2008 John Wiley & Sons, Ltd.
Selektive, am Substrat bindende Proteaseinhibitoren
Authors: Hille‐Rehfeld Annette
Published: October 2008

Viele Enzymaktivitäten lassen sich durch Effektoren regulieren, die an das katalytische Zentrum oder ein allosterisches Zentrum des Enzyms binden. Jetzt kamen Wissenschaftler einem neuartigen Typ von Proteaseinhibitoren auf die Spur, die spezifisch an Proteinsubstrate binden und so deren proteolytische Spaltung hemmen.
Mainz und Freiburg
Authors: Schwedt Georg
Published: October 2008

Von der Gesellschaft Deutscher Chemiker (GDCh) wird an Wirkungsstätten bedeutender Chemiker durch Gedenktafeln und an die Forschung der Wissenschaftler durch die Herausgabe einer Broschüre erinnert. Auf diese Weise werden einer breiteren Öffentlichkeit historische Wurzeln und das kulturelle Erbe der Chemie bekannt gemacht.
Stream Temperature Trends in Turkey
Authors: Albek Mine , Albek Erdem
Published: October 2008

Stream temperature is an important property of water and affects most other water quality constituents. It is also a property which is very much influenced by exogenous factors like air temperature and stream flow. This study investigates long‐term trends in stream temperatures measured at various stream monitoring stations in Turkey to better understand links with climate change. It was found by statistical trend analysis that more streams have experienced decreasing trends than increasing ones. Moreover, stream temperatures show a rising tendency in most stations over Turkey. Flow‐adjusted temperatures were computed to eliminate flow dependency and these show more positive than negative trends. Management plans of streams and watersheds need to take this into account and incorporate the implications into plans.
Prognostic factors and a scoring system for survival after radiotherapy for metastases to the spinal column
Authors: Mizumoto Masashi , Harada Hideyuki , Asakura Hirofumi , Hashimoto Takayuki , Furutani Kazuhisa , Hashii Haruko , Takagi Tatsuya , Katagiri Hirohisa , Takahashi Mitsuru , Nishimura Tetsuo
Published: October 2008

BACKGROUND.

To optimize selection of a radiotherapy schedule for patients with spinal metastases, the authors analyzed prognostic factors and developed a scoring system to predict survival in such patients.

METHODS.

Five‐hundred forty‐four patients with spinal metastases received radiotherapy at Shizuoka Cancer Center Hospital between September 2002 and November 2006. Prognostic factors for survival were studied using a Cox proportional hazards model, and a scoring system was developed based on regression coefficients: Three points were given for an unfavorable tumor type and bad performance status (≥3); 2 points were given for hypercalcemia, visceral metastases, and previous chemotherapy; and 1 point was given for multiple bone metastases and age ≥71 years.

RESULTS.

The overall survival rates after 6 months, 12 months, and 24 months were 49%, 32%, and 19%, respectively, and the median survival was 5.9 months (95% confidence interval, 4.9‐6.8 months). In total, 503 patients (93%) were followed for ≥12 months or until death. These patients were separated into Groups A, B, and C based on scores of 0 to 4, 5 to 9, and 10 to 14, respectively. These groups included 24%, 57%, and 19% of patients, respectively; and the mean median survival for Groups A, B, and C was 27.1 months, 5.4 months, and 1.8 months, respectively. Overall survival rates after 6 months, 12 months, and 24 months were 89%, 77%, and 54% in Group A; 46%, 22%, and 9% in Group B; and 7%, 4%, and 0% in Group C, respectively (P < .001).

CONCLUSIONS.

The scoring system was able to predict the survival of patients with spinal metastases and may be useful for selecting an optimal radiotherapy schedule. Cancer 2008. © 2008 American Cancer Society.
Evaluation of second‐order derivative of potential on boundary by discontinuous boundary element with exact integrations
Authors: Zhang Xiaosong , Zhang Xiaoxian
Published: October 2008

Exact integration of discontinuous quartic boundary element for evaluation of potential, its first‐order and second‐order derivative is presented. A patch test problem with three kinds of boundary conditions is implemented to show that the discontinuous boundary element with exact integration can evaluate the potential, its first‐order and second‐order derivative on boundary with high accuracy. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of methamphetamine exposure and cross‐fostering on sensorimotor development of male and female rat pups
Authors: Hrubá Lenka , Schutová Barbora , Šlamberová Romana , Pometlová Marie , Rokyta Richard
Published: October 2008

The present study tested the hypothesis that cross‐fostering influences the development of rat pups. Mothers were exposed daily to injection of methamphetamine (M) (5 mg/kg) or saline for 9 weeks: 3 weeks prior to impregnation, throughout gestation and lactation periods. Control females animals without any injections were used. On postnatal day (PD) 1, pups were cross‐fostered so that each mother received four pups of her own and eight pups from the mothers with the other two treatments. Offspring were tested for sensorimotor development in preweaning period by using tests of: negative geotaxis, tail pull, righting reflexes, rotarod and bar‐holding. Further, the pups were weighed daily. Our results showed that birth weight in prenatally M‐exposed pups was lower than in control or saline‐exposed pups. Prenatally M‐exposed pups gained less weight than control or saline‐exposed pups regardless of postnatal treatment and sex. Further, our data demonstrated that prenatal and postnatal M exposure impairs sensorimotor functions in most of the tests. On the other hand, the negative effect of prenatal M exposure was partially suppressed in prenatally M‐exposed pups by cross‐fostering to control dams. Our hypothesis that cross‐fostering may affect postnatal development of pups was confirmed. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 51: 73–83, 2009
Coupons going wireless: Determinants of consumer intentions to redeem mobile coupons
Authors: Dickinger Astrid , Kleijnen Mirella
Published: October 2008

Firms are increasingly using the mobile media for communication and promotion and Short Message Service (SMS), in particular. This study investigates consumers’ intentions to redeem mobile (m-) coupons. Results from a survey of 370 mobile phone users in Austria indicate that consumers’ attitude toward and perceived control of m-coupons affect their intention to redeem such coupons. The effort involved in redeeming m-coupons strongly affects consumers’ attitudes toward m-coupons, and fear of mobile spam influences consumers’ perceived control with regard to commercial SMS. Value seekers are more sensitive to the effort involved in redeeming m-coupons and to mobile spam than are other consumers. The results suggest that firms should not overwhelm consumers with m-coupons, consider the usability of m-coupons in deciding the right offer, and educate their consumers about how to use the m-coupons.
Spin Canting in a Cobalt(II) Radical Complex with an Acentric Counter Anion
Authors: Mitsumoto Kiyotaka , Shiga Takuya , Nakano Motohiro , Nihei Masayuki , Nishikawa Hiroyuki , Oshio Hiroki
Published: October 2008

Cobalt(II) radical complexes with centric and acentric counter anions, [CoCl(bisimpy)(MeOH)2]X [bisimpy = 2,6‐bis(4′,4′,5′,5′‐tetramethyl‐4′,5′‐dihydro‐1′H‐imidazol‐1′‐oxyl‐2′‐yl)pyridine; X = PF6 (1), and ClO4 (2)], crystallize in the centrosymmetric and polar space groups, respectively. Compound 1 is paramagnetic, whereas spin canting in 2 leads to a metamagnetic transition with a critical field of 1300 Oe at 1.8 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Chemical and enzymatic interesterification of tristearin/ triolein‐rich blends: Chemical composition, solid fat content and thermal properties
Authors: Ahmadi Latifeh , Wright Amanda J. , Marangoni Alejandro G.
Published: October 2008

Blends of high‐oleic sunflower oil and fully hydrogenated canola oil were subjected to enzymatic and chemical interesterification using Candida antarctica lipase (5%) and sodium methoxide (0.3%), respectively. The effect of each interesterification process was determined by comparing the triacylglycerol (TAG) composition, solid fat content (SFC) profiles and thermal properties of the blends before and after interesterification. Interesterification resulted in a decrease in the concentration of triunsaturated and trisaturated TAG and an increase in the proportion of mono‐ and disaturated TAG. These alterations in TAG composition and the presence of a greater variety of TAG species upon interesterification was correlated with a broader melting transition by differential scanning calorimetry and, ultimately, a lower melting point for the interesterified blends. Much broader ranges in plasticity were observed for the interesterified blends (chemically and enzymatically) compared to the physical blends. Even though ideal solubility of stearin in oil was observed, the value predicted by the Hildebrand model was higher than the actual amount. Crystallization kinetic parameters (Avrami index and rate constant) were similar for the non‐interesterified, enzymatically interesterified and chemically interesterified blends when compared as a function of SFC. Results from this work will aid in the formulation of more healthy fat and oil products and address a critical industrial demand in terms of formulation options for spreads, margarines and shortenings.
Enrichment of pomace olive oil in triterpenic acids during storage of “Alpeorujo” olive paste
Authors: García Aranzazu , Brenes Manuel , Dobarganes Mª Carmen , Romero Concepción , Ruiz‐Méndez Ma Victoria
Published: October 2008

Triterpenic acids are natural compounds present in plants and foods with beneficial properties for human health and thus they are desirable in the food, cosmetics and pharmaceutical industries. Pomace olive is considered a good source of these substances. In this study, oleanolic and maslinic acids were found to be the main triterpenic acids identified in pomace olive oil obtained from stored “Alpeorujo”. Determination of the two acids was achieved by a new procedure that consists of extracting the acids from the oil with a mixture of methanol/ethanol, and then separating and quantifying them by HPLC. Results showed that their concentration increased up to 16 g/kg of oil during storage of the pomace in large ponds for 7 months. The concentration of both triterpenic acids was similar in the pomace olive oil obtained by using the centrifugation system. By contrast, a much lower concentration of maslinic than oleanolic acid was detected in pomace olive oils obtained by solvent extraction from the previously centrifugated “Alpeorujo” paste. These triterpenic acids also contributed to the acidity of the crude oil. Likewise, the oil of the pomace paste was enriched in other substances such as 4‐ethylphenol and aliphatic alcohols during the storage of the paste in large ponds. Consequently, crude pomace olive oil can be considered a good source of triterpenic acids when obtained from a stored olive paste.
Residual Dipolar Couplings (RDCs) in Organic Structure Determination
Authors: Thiele Christina M.
Published: October 2008

After the huge impact that residual dipolar couplings (RDCs) have had on the structure determination of biological macromolecules by NMR spectroscopy, their utility in the structure determination of small/medium‐sized organic compounds is more and more recognised. This microreview will provide a short overview on how to introduce the anisotropic environment necessary to measure RDCs, the corresponding measurement methods and the applications for the determination of the relative configurations and the assignment of diastereotopic moieties. Their application to rigid compounds will be described, as will their very promising application to more flexible compounds, which is an area in which RDCs are expected to yield information that is not accessible by any other NMR spectroscopic means. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Cyclic Metalated Nitriles: Stereoselective Cyclizations to cis‐ and trans‐Hydrindanes, Decalins, and Bicyclo[4.3.0]undecanes
Authors: Fleming Fraser F. , Gudipati Subramanyham
Published: October 2008

Metalated nitriles are nucleophilic chameleons whose precise identity is determined by the nature of the metal, the solvent, the temperature, and the structure of the nitrile. The review surveys the different structural types and their cyclization trajectories to show how to selectively tune the metalated nitrile geometry for stereoselective cyclizations to a variety of cis or trans hydrindanes, decalins, and bicyclo[4.3.0]undecanes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Regioselective Synthesis of 4,5‐Diaryl‐1‐methyl‐1H‐imidazoles Including Highly Cytotoxic Derivatives by Pd‐Catalyzed Direct C‐5 Arylation of 1‐Methyl‐1H‐imidazole with Aryl Bromides
Authors: Bellina Fabio , Cauteruccio Silvia , Di Fiore Annarita , Rossi Renzo
Published: October 2008

A general and efficient three‐step procedure for the highly regioselective synthesis of 1‐methyl‐1H‐imidazoles possessing electron‐rich, electron‐neutral, and/or electron‐deficient aryl moieties at their 4‐ and 5‐positions is described. The first step involves the Pd‐catalyzed direct C‐5 arylation of commercially available 1‐methyl‐1H‐imidazole with aryl bromides, and the second and third steps of the sequence involve the selective C‐4 bromination of the resulting 5‐aryl‐1‐methyl‐1H‐imidazoles with NBS, followed by a PdCl2(dppf)‐catalyzed Suzuki‐type reaction between 5‐aryl‐4‐bromo‐1‐methyl‐1H‐imidazoles and arylboronic acids under phase‐transfer conditions. Two 4,5‐diaryl‐1‐methyl‐1H‐imidazoles so prepared, which can be regarded as Z‐restricted analogues of naturally occurring combretastatin A‐4 (CA‐4), proved to be highly cytotoxic against a variety of human tumor cell lines, and one of these derivatives has been shown to be more cytotoxic than CA‐4 and all of the imidazole derivatives investigated in the literature thus far. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
TMSOTf‐Promoted Addition of Alkynes to Aldehydes: A Novel Synthesis of Chroman‐4‐ones
Authors: Park Ji Yeon , Ullapu Punna Reddy , Choo Hyunah , Lee Jae Kyun , Min Sun‐Joon , Pae Ae Nim , Kim Youseung , Baek Du‐Jong , Cho Yong Seo
Published: October 2008

A novel synthetic method to prepare chalcones 2 and chroman‐4‐ones 3 by TMSOTf‐promoted addition of alkynes 1 to various aldehydes has been developed. The ratios of chalcones 2, chroman‐4‐ones 3 and hydrated products 4 varied depending upon the substituents R (nBu, phenyl, H and TMS) on the alkynes 1. We also describe the transformation of the chalcones 2 to the corresponding chroman‐4‐ones 3 under basic conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Second‐order diagnostics for space‐time point processes with application to seismic events
Authors: Adelfio Giada , Chiodi Marcello
Published: October 2008

A diagnostic method for space‐time point process is introduced and used to interpret and assess the goodness of fit of particular models to real data such as the seismic ones. The proposed method is founded on the definition of a weighted process and allows to detect second‐order features of data, like long‐range dependence and fractal behavior, that are not accounted for by the fitted model. Applications to earthquake data are provided. Copyright © 2008 John Wiley & Sons, Ltd.
Determination of shortest distance to voltage instability with particle swarm optimization algorithm
Authors: Chen M. J. , Wu B. , Chen C.
Published: October 2008

Loading margin denotes how close the power system is to voltage instability. This paper presents a new technique to obtain the shortest distance to voltage instability, which converts the computation of the closest point of collapse to an optimization problem. Compared with the existing methods, the notable advantage of this technique is the capability of dealing with various constraints such as generation reactive power limits expediently and of finding out the global shortest distance to instability instead of local one, so that the shortest distance obtained corresponds to the practical system operation and then effective measures may be taken to prevent voltage collapse according to the results. A modified particle swarm optimization algorithm is presented to solve this optimization problem. Of the proposed algorithm, local optimum areas are ascertained and further exploring is implemented to find genuine local optima. Recruiting new particles outside the ascertained local optimum areas enhances the global search stability of the proposed algorithm. Details of the optimization problem and the implementation of the proposed optimization method to test systems are presented and the feasibility and validity are demonstrated. Copyright © 2008 John Wiley & Sons, Ltd.
Source encoding with efficient transmission of CSI in multiuser MIMO–OFDMA downlink
Authors: Yi Liu , Hailin Zhang
Published: October 2008

This paper investigates the problem of source encoding in multiuser multiple‐input multiple‐output (MIMO)–orthogonal frequency division multiplexing (OFDMA) downlink with a limited feedback channel. The proposed encoding scheme, including beamforming, subcarrier distribution and rate loading, applies a pre‐designed codebook of beamforming vectors, which is stored at both the transmitter and the receiver. The receiver selects the beamforming vector and user for each subcarrier aiming at SINR maximization and conveys the index of the chosen vector and equivalent gain to the transmitter. At the transmitter, the rate is loaded to each subcarrier using the ‘greedy’ algorithm. The methods of codebook construction and rate loading are discussed in detail. Simulation results show that the scheme decreases the amount of feedback data while maintaining quite a large downlink capacity and the capacity approaches that of perfect CSI with an increase in codebook elements. Copyright © 2008 John Wiley & Sons, Ltd.
A robust cell search scheme for OFDMA systems
Authors: Li Li , Zhou Ping , Hu Honglin , Zhang Xiaodong
Published: October 2008

One essential stage in orthogonal frequency‐division multiple access (OFDMA) downlink is cell search, which is the initialisation for the access of the users to the communication networks. This paper proposes a robust cell search structure for the OFDMA system based on constant amplitude zero auto‐correlation (CAZAC) sequences, namely an orthogonal allocation (OA) scheme. Simulation results show that the cell identification capability has been improved remarkably, especially for the users at the cell boundary. Copyright © 2008 John Wiley & Sons, Ltd.
Faszination Forschung
Authors: Kleiner Matthias
Published: October 2008

Zwischen Big Science und Basis – Oder: Was LHC‐Teilchenbeschleuniger und Koselleck‐Projekte verbindet
Seen in der Sahara
Authors: Kröpelin Stefan
Published: October 2008

Große Wasserflächen inmitten der Wüste sind nicht nur ein Naturspektakel, sondern auch ein hochpräzises Umweltarchiv. Die aus ihnen gewonnenen Sedimente dokumentieren die Klimaentwicklung und geben Aufschluss über Staubstürme, Savannenbrände und Vulkanausbrüche. Eine Reise in den Nordosten des Tschad.
Synthesis of Dispersed and Contiguous Nanoparticles in Solid Oxide Fuel Cell Electrodes
Authors: Sholklapper T. Z. , Jacobson C. P. , Visco S. J. , De Jonghe L. C.
Published: October 2008

Solid oxide fuel cell (SOFC) electrodes, after their high temperature sintering, may be impregnated (infiltrated) to deposit nanoparticles within their pores. There are two main motivations for modifying the electrodes: (i) to add catalytic function, and (ii) to enhance electronic or ionic conduction pathways, since either or both may not be sufficient within the as‐sintered electrodes. The impregnated particles take on two configurations: dispersed or connected. While dispersed nanoparticles introduce catalysts, connected nanoparticulate networks can add conduction paths in addition to enhancing catalysis. This paper reviews the prevalent SOFC electrode types, the function of the impregnated nanoparticles, and the common impregnation methods. Specific attention is given to the optimal uses of each method, with positives and negatives addressed for each.
Impact of wildfire on source water contributions in Devil Creek, CA: evidence from end‐member mixing analysis
Authors: Jung Helen Y. , Hogue Terri S. , Rademacher Laura K. , Meixner Tom
Published: October 2008

A geochemical and end‐member mixing analysis (EMMA) is undertaken in Devil Canyon catchment, located in southern California, to further understanding of watershed behaviour and source water contributions after an acute and extensive wildfire. Physical and chemical transformations in post‐fire watersheds are known to increase overland flow and decrease infiltration, mainly due to formation of a hydrophobic layer at, or near, the soil surface. However, less is known about subsurface flow response in burned watersheds. The current study incorporates EMMA to evaluate and quantify source water contributions before, and after, a catchment affected by wildfires in southern California during the fall of 2003. Pre‐ and post‐fire stream water data were available at several sampling sites within the catchment, allowing the identification of contributing water sources at varying spatial scales. Proposed end‐member observations (groundwater, overland flow, shallow subsurface flow) were also collected to constrain and develop the catchment mixing model. Post‐fire source water changes are more evident in the smaller and faster responding sub‐basin (interior sampling point). Early post‐fire storm events are dominated by overland flow with no significant soil water or groundwater flow contribution. Inter‐storm streamwater in this smaller basin shows an increase in groundwater and a decrease in soil water. In the larger, baseflow‐dominated system, source water components appear less affected by fire. A slight increase in lateral flow is observed with only a slight decrease in baseflow. Changes in the post‐fire flow regimes affect nutrient loading and chemical response of the basin. Relatively rapid recovery of the chaparral ecosystem is evidenced, with active re‐growth and evapotranspiration evidenced by the fourth post‐fire rainy season. Copyright © 2008 John Wiley & Sons, Ltd.