bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and characterization of a salivary adenosine deaminase from the sand fly Phlebotomus duboscqi, the vector of Leishmania major in sub-Saharan Africa
Authors: Kato Hirotomo , Jochim Ryan C. , Lawyer Phillip G. , Valenzuela Jesus G.
Published: February 2007

Two transcripts coding for an adenosine deaminase (ADA) were identified by sequencing a Phlebotomus duboscqi salivary gland cDNA library. Adenosine deaminase was previously reported in the saliva of the sand fly Lutzomyia longipalpis but it was not present in the saliva of the sand flies Phlebotomus papatasi, P. argentipes, P. perniciosus and P. ariasi, suggesting that this enzyme is only present in the saliva of sand flies from the genus Lutzomyia. In the present work, we tested the hypothesis that the salivary gland transcript coding for ADA in Phlebotomus duboscqi, a sister species of Phlebotomus papatasi, produces an active salivary ADA.

Salivary gland homogenates of P. duboscqi converted adenosine to inosine, suggesting the presence of ADA activity in the saliva of this species of sand fly; furthermore, this enzymatic activity was significantly reduced when using either salivary glands of recently blood-fed sand flies or punctured salivary glands, suggesting that this enzyme is secreted in the saliva of this insect. This enzymatic activity was absent from the saliva of P. papatasi. In contrast to other Phlebotomus sand flies, we did not find AMP or adenosine in P. duboscqi salivary glands as measured by HPLC-photodiode array. To confirm that the transcript coding for ADA was responsible for the activity observed in the saliva of this sand fly,we cloned this transcript into a prokaryotic expression vector and produced a soluble and active recombinant protein of approximately 60 kDa that was able to convert adenosine to inosine. Extracts of bacteria transformed with control plasmids did not show this activity. These results suggest that P. duboscqi transcripts coding for ADA are responsible for the activity detected in the salivary glands of this sand fly and that P. duboscqiacquired this activity independently from other Phlebotomus sand flies. This is another example of a gene recruitment event in salivary genes of blood-feeding arthropods that may be relevant for blood feeding and,because of the role of ADA in immunity, it may also play a role in parasite transmission.
Morphometry of retinal vasculature in Antarctic fishes is dependent upon the level of hemoglobin in circulation
Authors: Wujcik Jody M. , Wang George , Eastman Joseph T. , Sidell Bruce D.
Published: February 2007

We quantitatively assessed ocular vascular patterns of six Antarctic notothenioid fishes that vary in their expression of the circulating oxygen-binding protein, hemoglobin (Hb). Digital image analyses revealed marked differences in vessel morphometries among notothenioid species. Hemoglobinless (–Hb) icefishes display mean vessel length densities that are greater (Chaenocephalus aceratus, 5.51±0.32 mm mm–2; Champsocephalus gunnari, 5.15±0.50 mm mm–2) than those observed in red-blooded (+Hb) species(Gymnodraco acuticeps, 5.20±0.46 mm mm–2; Parachaenichthyes charcoti, 4.40±0.30 mm mm–2; Trematomus hansoni, 3.94±0.08 mm mm–2; Notothenia coriiceps, 2.48±0.21 mm mm–2). –Hb fishes also have mean vessel diameters that are ∼1.5 times greater than vessel diameters of +Hb species (–Hb,0.193±0.006 mm; +Hb, 0.125±0.005 mm). Vascular density index(VDI), a stereological index that is affected by both vessel number and length, is greatest in –Hb C. aceratus (3.51±0.20) and lowest in +Hb N. coriiceps (1.58±0.14). Among four +Hb species, there is a direct relationship between red blood cell content and retinal vasculature. Hematocrit (Hct) is inversely correlated to vascular density (r2=0.934) and positively correlated to intervessel distance (r2= 0.898) over a >2.3-fold range of Hct. These results indicate that anatomical capacity to supply blood to the retina increases to compensate for decreases in oxygen-carrying capacity of the blood.
Phosphoglucose isomerase genotype affects running speed and heat shock protein expression after exposure to extreme temperatures in a montane willow beetle
Authors: Rank Nathan E. , Bruce Douglas A. , McMillan David M. , Barclay Colleen , Dahlhoff Elizabeth P.
Published: February 2007

Eastern Sierra Nevada populations of the willow beetle Chrysomela aeneicollis commonly experience stressfully high and low environmental temperatures that may influence survival and reproduction. Allele frequencies at the enzyme locus phosphoglucose isomerase (PGI) vary across a climatic latitudinal gradient in these populations, with PGI allele 1 being most common in cooler regions and PGI allele 4 in warmer ones. PGI genotypes differ in heat and cold tolerance and in expression of a 70 kDa heat shock protein. Here we examine genetic, behavioral and environmental factors affecting a performance character, running speed, for willow beetles, and assess effects of consecutive cold and heat exposure on running speed and expression of Hsp70 in the laboratory. In nature, running speed depends on air temperature and is higher for males than females. Mating beetles ran faster than single beetles, and differences among PGI genotypes in male running speed depended on the presence of females. In the laboratory, exposure to cold reduced subsequent running speed, but the amount of this reduction depended on PGI genotype and previous thermal history. Effects of exposure to heat also depended on life history stage and PGI genotype. Adults possessing allele 1 ran fastest after a single exposure to stressful temperature, whereas those possessing allele 4 ran faster after repeated exposure. Larvae possessing allele 4 ran fastest after a single stressful exposure, but running speed generally declined after a second exposure to stressful temperature. The ranking of PGI genotypes after the second exposure depended on whether a larva had been exposed to cold or heat. Effects of temperature on Hsp70 expression also varied among PGI genotypes and depended on type of exposure, especially for adults (single heat exposure, two cold exposures: PGI 1-1>1-4>4-4;other multiple extreme exposures: 4-4>1-4>1-1). There was no consistent association between alleles at other polymorphic enzyme loci and running speed or Hsp70 expression. These data suggest that variation at PGI is associated with considerable plasticity in running speed. Differences in Hsp70 expression among PGI genotypes suggest that the heat-shock response may buffer differences in thermal tolerance and performance among genotypes and help maintain the PGI polymorphism in a thermally variable environment.
Cloacal evaporation: an important and previously undescribed mechanism for avian thermoregulation
Authors: Hoffman Ty C.M. , Walsberg Glenn E. , DeNardo Dale F.
Published: February 2007

We present the first experimental evidence that a bird is capable of evaporating enough water from the cloaca to be important for thermoregulation. We measured rates of evaporation occurring from the mouth, the skin, and the cloaca of Inca doves Columbina inca Lesson and Eurasian quail Coturnix coturnix Linnaeus. Inca doves showed no significant increase in cutaneous evaporation in response to curtailment of buccopharyngeal evaporation. Cloacal evaporation in doves was negligible at ambient temperatures of 30°, 35° and 40°C. However, at 42°C, the apportionment of total evaporation in doves was 53.4% cutaneous, 25.4%buccopharyngeal and 21.2% cloacal, with cloacal evaporation shedding, on average, 150 mW of heat. In contrast, the evaporative apportionment in quail at 32°C (the highest ambient temperature tolerated by this species) was 58.2% cutaneous, 35.4% buccopharyngeal and 6.4% cloacal. These results suggest that, for some birds, cloacal evaporation can be controlled and could serve as an important emergency tactic for thermoregulation at high ambient temperatures.
Structural complexity of chemical recognition cues affects the perception of group membership in the ants Linephithema humile and Aphaenogaster cockerelli
Authors: Greene Michael J. , Gordon Deborah M.
Published: February 2007

Hydrocarbon profiles on the cuticle of social insects act as multi-component recognition cues used to identify membership in a species, a colony or, within colonies, cues about its reproductive status or task group. To examine the role of structural complexity in ant hydrocarbon recognition cues, we studied the species recognition response of two ant species, Linepithema humile and Aphaenogaster cockerelli, and the recognition of conspecifics by L. humile. The cuticular hydrocarbons of ants are composed of molecules of varying chain lengths from three structural classes, n-alkanes, methyl-branched alkanes and n-alkenes. We employed species recognition bioassays that measured the aggressive response of both species of ants to mixtures of hydrocarbon classes, single structural classes of hydrocarbons (n-alkanes,methyl-branched alkanes and n-alkenes), and controls. The results showed that a combination of at least two hydrocarbon structural classes was necessary to elicit an aggressive species recognition response. Moreover, no single class of hydrocarbons was more important than the others in eliciting a response. Similarly, in the recognition of conspecifics, Linepithema humile did not respond to a mixture of n-alkane cuticular hydrocarbons presented alone, but supplementation of nestmate hydrocarbon profiles with the n-alkanes did elicit high levels of aggression. Thus both L. humile and A. cockerelli required mixtures of hydrocarbons of different structural classes to recognize species and colony membership. It appears that information on species and colony membership is not in isolated components of the profile, but instead in the mixture of structural classes found in cuticular hydrocarbon profiles.
Slow dehydration promotes desiccation and freeze tolerance in the Antarctic midgeBelgica antarctica
Authors: Hayward Scott A. L. , Rinehart Joseph P. , Sandro Luke H. , Lee Richard E. , Denlinger David L.
Published: February 2007

Adaptations to low moisture availability are arguably as important as cold resistance for polar terrestrial invertebrates, especially because water, in the form of ice, is biologically inaccessible for much of the year. Desiccation responses under ecologically realistic soil humidity conditions– those close to the wilting points of plants [98.9% relative humidity(RH)] – have not previously been examined in polar insect species. In the current study we show that, when desiccated at 98.2% RH, larvae of the Antarctic midge Belgica antarctica are more tolerant of dehydration than larvae desiccated at lower humidities (75% RH), and develop an increased tolerance to freezing. The slow rate of desiccation at this high RH enabled more than 50% of larvae to survive the loss of >75% of their osmotically active water (OAW). Survival rates were further increased when rehydration was performed at 100% RH, rather than by direct contact with water. Two days at 98.2% RH resulted in a ∼30% loss of OAW, and dramatically increased the freeze tolerance of larvae to –10 and –15°C. The supercooling point of animals was not significantly altered by this desiccation treatment,and all larvae were frozen at –10°C. This is the first evidence of desiccation increasing the freeze tolerance of a polar terrestrial arthropod. Maximum water loss and body fluid osmolality were recorded after 5 days at 98.2% RH, but osmolality values returned to predesiccated levels following just 1 h of rehydration in water, well before all the water lost through desiccation had been replenished. This suggests active removal of osmolytes from the extracellular fluids during the desiccation process, presumably to intracellular compartments. Heat-shock proteins appear not to contribute to the desiccation tolerance we observed in B. antarctica. Instead, we suggest that metabolite synthesis and membrane phospholipid adaptation are likely to be the underpinning physiological mechanisms enhancing desiccation and cold tolerance in this species.
Transition Metal-Catalyzed Organometallic Reactions that Have Revolutionized Organic Synthesis
Authors: Negishi Ei-ichi
Published: February 2007

The Pd- or Ni-catalyzed cross-coupling reactions of organometals containing Zn, Al, Zr, and B as well as related reactions of Mg and several other metals collectively represent the most widely applicable organic skeleton construction method discovered and developed over the past several decades, allowing the synthetic chemists to synthesize practically all types of organic compounds. Some of the seminal and critically important discoveries and early developments in the 1970s as well as their current scope (Tables 2 and 3) are briefly discussed. Some of the notable discoveries and developments include (1) identification of superior properties of Pd relative to Ni, (2) the broad scope of Pd- or Ni-catalyzed cross-coupling with respect to metal counter cations including Zn, Al, Zr, B, and Mg, (3) the hydrometallation–Pd-catalyzed cross-coupling tandem processes for selective syntheses of alkenes, dienes, oligoenes, and oligoenynes, (4) double metal catalysis involving Pd or Ni and added metal compounds containing Zn, In, Li, and others, and (5) realization of high turnover numbers (≥103–105) through the use of chelating phosphines, such as DPEphos and dppf. In these reactions, the metal counter cations in organometals and Pd or Ni are to work successively via transmetallation. The Zr-catalyzed alkyne carboalumination and the Zr-catalyzed asymmetric carboalumination of alkenes (ZACA reaction) have provided efficient and selective routes to methyl-branched (E)-trisubstituted alkenylalanes and 2-substituted chiral alkylalanes, respectively. These reactions provide two additional examples of prototypical transition metal-catalyzed organometallic reactions. Significantly, they can be readily combined with the Pd- or Ni-catalyzed cross-coupling for the synthesis of trisubstituted alkenes embracing a wide variety of natural products, such as terpenoids, carotenoids, and others, as well as various chiral organics including deoxypolypropionates and saturated terpenoids. The Zr-catalyzed alkyne carboalumination has been applied to the synthesis of well over 100 complex natural products (Table 4), while the ZACA reaction has been transformed from a mere scientific novelty to a full-fledged asymmetric synthetic method that is catalytic in both transition metal (Zr) and chiral auxiliaries through a series of breakthroughs (Schemes 12–17).
A Helmeted Dialkylsilylene
Authors: Kira Mitsuo , Iwamoto Takeaki , Ishida Shintaro
Published: February 2007

Structural characteristics, spectroscopic properties, and unique reactions of a helmeted dialkylsilylene, 2,2,5,5-tetrakis(trimethylsilyl)silacyclopentane-1,1-diyl, that was synthesized as the first isolable dialkylsilylene and its application to the synthesis of novel silicon unsaturated compounds are surveyed. The silylene was found to be the least electronically perturbed among known stable silylenes by 29Si NMR and UV–vis spectroscopies. The silylene reacts not only with well-known trapping reagents for transient silylenes, such as alcohols, triethylsilane, and 2,3-dimethylbutadiene, but also with less reactive haloalkanes and halosilanes to give the corresponding adducts. One-electron reduction of the silylene using alkali metals affords the corresponding radical anion as a relatively persistent species at low temperatures in solution. Irradiation of the silylene using visible light generates a singlet excited state with a lifetime of 80.5 ns, which reacts with various aromatic compounds and alkenes to give the corresponding silepins and siliranes in a highly regio- and stereoselective manner. The silylene is utilized for the synthesis of unique silicon unsaturated compounds, such as Si=X doubly bonded compounds (X = S, Se, Te, C=NR, etc.), a trisilaallene, a 1,3-disilagermaallene, and silylene transition-metal complexes.
Structural-Based Engineering for Transferases to Improve the Industrial Production of 5′-Nucleotides
Authors: Suzuki Ei-ichiro , Ishikawa Kohki , Mihara Yasuhiro , Shimba Nobuhisa , Asano Yasuhisa
Published: February 2007

The existence of a flexible region for substrate recognition by an enzyme was first discovered through a structure comparison study among ribonuclease T1–related molecules, including intact molecules, intact molecules complexed with 2′-guanylic acid (GMP), and carboxymethylated molecules complexed with 2′-GMP. Next, it was demonstrated that transglutaminase activity could be enhanced by identifying the flexible residues that affect the active site using nuclear magnetic resonance. Finally, such an approach was used to increase the production of 5′-inosinic acid (5′-IMP) and 5′-GMP. The enzyme is a nonspecific acid phosphatase with pyrophosphate-nucleoside phosphotransferase activity that is C-5′ position-selective. The crystal structure of G74D/I153T with a reduced KM is virtually identical to that of the wild type, and neither of the side chains that were introduced Asp74 and Thr153, directly interact with the nucleoside, although both residues are situated near a potential nucleoside binding site. In addition, the two regions around residues 70 and 140 have the most flexible conformational rearrangement upon phosphate analogue binding. On the basis of three-dimensional (3D) structural information, some practical, high-performance enzymes for 5′-nucleotides production were discovered, and new varieties of microorganisms were developed.
Luminescent Platinum Complexes Having Sensing Functionalities
Authors: Kato Masako
Published: February 2007

Square-planar platinum(II) complexes often exhibit intense color and luminescence when they are stacked via self-assembly or bridging by ligands. The origin of the color and luminescence are the metal–metal electronic interactions, and thus, remarkable changes in color (i.e., chromism) are expected by controlling the Pt···Pt interactions. The molecular arrangement of the assembled complex systems is sensitive to environmental factors such as temperature, pressure, solvent, and vapor. This account focuses on the sensing functionalities of luminescent platinum(II) complexes with 2,2′-bipyridine or its derivatives toward their environment. Especially, luminescence changes that are induced by the vapor molecules will be examined from the viewpoint of chemical sensing. The vapochromic behavior and structural aspects of the mononuclear and dinuclear platinum(II) complexes are discussed.
Organic Nanoparticles of Cyanine Dye in Aqueous Solution
Authors: Ou Zhong-min , Yao Hiroshi , Kimura Keisaku
Published: February 2007

Ion-based organic dye nanoparticles ranging from tens to hundreds of nanometers have been prepared in aqueous solution. The synthetic approach is based on “ion-association” (hydrophobic ion-pair formation) in water between the dye cation pseudoisocyanine (PIC) and the anion tetraphenylborate (TPB) or tetrakis(4-fluorophenyl)borate (TFPB) ion. Size tuning of spherical and amorphous PIC nanoparticles was accomplished by varying the molar ratio (ρ) of the loaded anion to the dye cation. Electrophoretic characterization revealed that the increase in surface adsorption of anions onto PIC particles brings about an increase in the negative surface charge density, causing a reduction in the surface tension and the mean size of nanoparticles. We found that the optical absorption properties of the PIC nanoparticles exhibited (i) matrix dependence, that is, the 0–0 band position of the PIC chromophore within similar-sized nanoparticles was dependent on the type of counter anions used, and (ii) size dependence, i.e., the 0–0 band position of the PIC chromophore was dependent on the mean nanoparticle diameter when the particles were prepared using the same counter anion.
DFT Calculations and IR Studies on 2-Hydroxy-1,4-naphthoquinone and Its 3-Substituted Derivatives
Authors: Satoh Takehiko , Tsuji Takemasa , Matsuda Hiroko , Sudoh Susumu
Published: February 2007

The carbonyl stretching vibrations of the title compounds were studied using DFT calculations at the B3LYP/6-311G** level and the IR spectra in terms of the intramolecular hydrogen bond (H-bond). Two types of H-bond systems were examined: type I in which the H-atom of the OH group points towards to neighboring carbonyl oxygen atom, and type II in which the H-atom points away. The results of the DFT calculations show that the IR spectra of 2-hydroxy-1,4-naphthoquinone (1), 3-chloro-2-hydroxy-1,4-naphthoquinone (2), 3-bromo-2-hydroxy-1,4-naphthoquinone (3), and 2-hydroxy-3-iodo-1,4-naphthoquinone (4) in CCl4, are well explained by the assumption of the two types of H-bond systems.
Control of Coordination and Luminescence Properties of Lanthanide Complexes Using Octadentate Oligopyridine-Amine Ligands
Authors: Wada Atsushi , Watanabe Masayuki , Yamanoi Yoshinori , Nankawa Takuya , Namiki Kosuke , Yamasaki Mikio , Murata Masaki , Nishihara Hiroshi
Published: February 2007

Lanthanide complexes with linear and cyclic octadentate oligopyridine-amine ligands were synthesized, and their molecular structures were determined by single-crystal X-ray crystallography. All of the complexes had a distorted capped square antiprism (CSAP) geometry, and the coordination environments of lanthanide complexes were more distorted for the complexes with the linear ligand than those with the cyclic ligand. The Eu3+ and Tb3+ complexes showed intense luminescence due to energy transfer from the ligand to the metal center (antenna effect). The Eu3+ complexes with the linear ligand showed more intense emissions, which were attributed to the 5D0 → 7F2 transition, than the complex with the cyclic ligand in acetonitrile, which can be attributed to the distortion in the coordination environments. In contrast, the coordination of water molecules to Eu3+ and Tb3+ ions was strongly prevented because the metal ions were surrounded by the cyclic ligand, resulting in intense luminescence in water. These results indicate that the coordination environments of lanthanide complexes, and thus the luminescence properties, can be controlled by tuning the geometrical structures of polydentate ligands.
Hydrogen Bond Donor Ability α2H Is a Good Index for Finding an Appropriate Color Developer for the Molecular Design of Functional Thermal Paper
Authors: Kawasaki Kazunori , Sakakibara Kazuhisa
Published: February 2007

Thermal paper, which is comprised of sulfonylurea molecule R1SO2NH–CO–NH–R2 (color developer) and the leuco-dye, can develop strong black color, and the developed color is durable. This is because sulfonylurea functional group has sufficient hydrogen bond donor ability to stabilize a π-delocalized carbocation generated from the leuco-dye due to heat-induced lactone ring opening. Thus, the color-developing complex (CDC) that appears can be stabilized by hydrogen-bond formation between two N–H bonds of the sulfonylurea and the carboxylate anion from the leuco-dye. The hydrogen bond donor ability of the color developer can be evaluated in terms of the α2H parameter proposed by Abraham. 1H NMR chemical shift values of the N–H protons in the sulfonylurea and HPLC retention times of the sulfonylurea on a silica column show a good correlation with the α2H parameter values. The essential factors necessary for the sulfonylurea to give rise to high color developing by forming a stable hydrogen-bond complex are also discussed on the basis of the structure and the electronic properties of the sulfonylureas.
Total Synthesis and Cytotoxicity of (+)- and (−)-Goniodiol and 6-epi-Goniodiol. Construction of α,β-Unsaturated Lactones by Ring-Closing Metathesis
Authors: Nakashima Katsuyuki , Kikuchi Naoki , Shirayama Daisuke , Miki Takuo , Ando Kazuhiro , Sono Masakazu , Suzuki Shinya , Kawase Masaki , Kondoh Masuo , Sato Masao , Tori Motoo
Published: February 2007

(+)-Goniodiol, a potent and selective cytotoxin, and (−)-6-epi-goniodiol, as well as their enantiomers, have been synthesized starting from cinnamyl alcohol. The key steps of the synthesis were Sharpless asymmetric epoxidation and cyclization of an acrylate derivative using ring-closing metathesis reaction. The cytotoxicity of both enantiomers of goniodiol and 6-epi-goniodiol against HL-60 cells was examined.
Electrochemical A-Ring Bromination of Estrogens
Authors: Damljanovic Ivan , Vukicevic Mirjana , Vukicevic Rastko D
Published: February 2007

A-ring bromination of estrogens has been achieved by constant current electrolysis of the solutions of these substrates and Et4NBr in appropriate solvents. Thus, electrolysis consuming 2 F mol−1 charge gave mixtures of 2- and 4-estrogens (1:1.1–2.5; up to 97%), whereas 4 F mol−1 charge experiments yielded 2,4-dibromoestrogens as the sole products.
Novel Oligomers of 9,9-Dialkylated Fluorenes for Thermally Stable Hole-Transport Materials in OLEDs
Authors: Kimura Makoto , Kurata Toshihiko , Sawaki Yasuhiko , Toba Yasumasa , Enokida Toshio , Takagi Katsuhiko
Published: February 2007

Using 9,9-dialkyl-functionalized fluorenes as monomers, novel fluorene-based oligomers were prepared in order to improve the thermal stability of a typical hole-transport material (HTM), N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD), in organic light emitting diodes (OLEDs). 2,7-Bis(diphenylamino)fluorene was utilized as a TPD unit throughout the present synthetic work. 9,9-Bis(2-methylallyl)fluorene and its TPD congener underwent a new cyclopolymerization reaction affording six-membered oligomers under acid catalysis with p-toluenesulfonic acid. Intermolecular Suzuki coupling of a 9,9-bis(p-bromobenzyl)fluorene analogue with the corresponding bis-boronate afforded a new oligomer containing the TPD substructure. These oligomers (3 and 6) for use as HTMs have high glass-transition temperatures (Tg’s) (147 and 167 °C, respectively); the values are much higher than the Tg for TPD (63 °C). These materials are soluble in organic solvents to allow easy processing for preparing layered devices, though their electroluminescent performances were lower than that of the single molecule TPD.
Hydrothermal Synthesis of Fine NaTaO3 Powder as a Highly Efficient Photocatalyst for Overall Water Splitting
Authors: Lee Yungi , Watanabe Tomoaki , Takata Tsuyoshi , Hara Michikazu , Yoshimura Masahiro , Domen Kazunari
Published: February 2007

A fine powder of sodium tantalum(V) trioxide as single-phase perovskite NaTaO3 has been successfully prepared by hydrothermal synthesis through the reaction of a sodium hydroxide solution and ditantalum pentaoxide powder at low temperature (373–473 K). The NaTaO3 powder has high photocatalytic activity for both H2 evolution (8.0 mmol h−1) and O2 evolution (4.1 mmol h−1), which is attributed to the high surface area, small particle size and high crystallinity of the powder catalyst.
Synthesis and Crystallization of Hexagonal Boron Nitride in Liquid Sodium Amide
Authors: Gu Yunle , Zheng Mingtao , Xu Zilin , Liu Yingliang
Published: February 2007

Hexagonal boron nitride was synthesized from MB6 (M = Ca and La) in liquid sodium amide at 600 °C. The as-synthesized boron nitride powders were composed of sub-micrometer-sized triangles and hexagons.
Dimensionality Reduction of near Infrared Spectral Data Using Global and Local Implementations of Principal Component Analysis for Neural Network Calibrations
Authors: Kovalenko Igor V. , Rippke Glen R. , Hurburgh Charles R.
Published: February 2007

The artificial neural network (ANN) learning algorithm is a strong alternative to traditional linear calibration methods used in near infrared (NIR) spectroscopy. The generalisation capacity of ANN can be effectively employed only when the ratio of available training samples to a number of neuron interconnection weights and biases (unknown regression parameters) is large. Traditionally, this ratio is increased by compressing X data to fewer variables using principal component analysis (PCA). An alternative method, local PCA compression, has been described in the literature. This approach overcomes the global linearity of PCA by performing dimensionality reduction in two steps: division of the data space into clusters and local compression of each cluster using PCA. This study compared global and local implementations of PCA compression in NIR calibration problems solved with ANN regression. Three data sets were used for development of control (based on PCA) and experimental (based on local PCA) ANN calibrations. The results demonstrated that local PCA could outperform traditional global PCA compression. However, the best dimensionality reduction method was case-dependent. Performance of local PCA-based calibrations degraded rapidly as compression rate increased, while global PCA allowed higher compression at minimal cost of prediction accuracy.
Using near Infrared Spectroscopy for Rapid Quantification of Sediment Dust in the Indoor Environment
Authors: Chudnovsky A. , Ben-Dor E. , Paz E.
Published: February 2007

The aim of this study was to develop and apply a novel sensitive technique, using near infrared (NIR) reflectance spectroscopy in the 1250–2400 nm region, to account for small amounts of sediment dust that settle on indoor surfaces. In order to quantitatively characterise the dust loading process and to determine the range of applicability, two composition mixture models, representing homogeneity (talc powder) and heterogeneity [dust analogue: Environmental Protected Agency (EPA) dust] of chemical compounds, were examined. A wind tunnel was constructed in order to quantitatively characterise the dust-loading process in a simulated environment. The influence of total mass loaded and the sensitivity of spectral measurements were tested. Based on the significant results in the simulated environment, a field study was conducted in different indoor environments in the Tel-Aviv area. Multivariate data analysis based on partial least squares regression was run to predict the dust loads solely from reflectance data. Different spectral manipulations were tested. The relative standard error for validation sets accepted for indoor dust was found to be low (11.5%). We conclude that this methodology can be employed to assess dust in an indoor environment for small and relatively high dust content (ranging between 0.01 mg cm−2 to 0.51 mg cm−2 for artificial mixtures and between 0.02 mg cm−2 to 0.45 mg cm−2 for field study, respectively).
Moving beyond Kyoto
Authors: McKibbin Warwick K.
Published: February 2007

In November 2000, just after the presidential elections in the United States, negotiators will meet in The Hague at the sixth meeting of the Conference of Parties (COP6) to the United Nations Framework Convention on Climate Chang the Kyoto Protocol on global climate change at COP3, which was held in Kyoto in December 1997. Intense negotiations over the intervening period have focused on how to implement the Kyoto Protocol. The Kyoto Protocol has been signed by 84 countries but not ratified by any of the key countries, and ratification does not appear to be imminent, especially in the United Sates, where the Senate has registered its strong opposition.
The role of semantic transparency in the processing of English compound words
Authors: Frisson Steven , Niswander‐Klement Elizabeth , Pollatsek Alexander
Published: February 2007

Experiment 1 examined whether the semantic transparency of an English unspaced compound word affected how long it took to process it in reading. Three types of opaque words were each compared with a matched set of transparent words (i.e. matched on the length and frequency of the constituents and the frequency of the word as a whole). Two sets of the opaque words were partially opaque: either the first constituent was not related to the meaning of the compound (opaque‐transparent) or the second constituent was not related to the meaning of the compound (transparent‐opaque). In the third set (opaque‐opaque), neither constituent was related to the meaning of the compound. For all three sets, there was no significant difference between the opaque and the transparent words on any eye‐movement measure. This replicates an earlier finding with Finnish compound words (Pollatsek & Hyönä, 2005) and indicates that, although there is now abundant evidence that the component constituents play a role in the encoding of compound words, the meaning of the compound word is not constructed from the parts, at least for compound words for which a lexical entry exists. Experiment 2 used the same compounds but with a space between the constituents. This presentation resulted in a transparency effect, indicating that when an assembly route is ‘forced’, transparency does play a role.
Conservation and conversation types: Forms of recognition and cognitive development
Authors: Psaltis Charis , Duveen Gerard
Published: February 2007

While the productive role of social interaction between peers in promoting cognitive development has been clearly established, the communicative processes through which this is achieved is less clearly understood. Earlier work has established that different types of conversation become established between children as they work together on a problem, and that these types have different implications for the progress of a non‐conserver. The paper focuses on the forms of recognition that emerge within these different conversation types. It reports further analyses of a study in which 226 6.5‐ to 7.5‐year‐old children were presented with a Piagetian task of conservation of liquid. Conservers and non‐conservers were asked to discuss in pairs their conflicting answers and agree upon a joint response. Cognitive progress was assessed by pre‐ to post‐test gains. Analyses of the conversational moves made by each of the participants to the conversation indicates that both non‐conservers and conservers not only make characteristic contributions, but that these contributions vary across the conversation types, and hence also relate differentially to the non‐conserver's progress. More detailed qualitative analyses of the different conversation types provide insights into the ways in which different forms of recognition emerge through these interactions. These results are discussed in relation to a socio‐cognitive account of development.
Playing with word endings: Morphological variation in the learning of Russian noun inflections
Authors: Kempe Vera , Brooks Patricia J. , Mironova Natalija , Pershukova Angelina , Fedorova Olga
Published: February 2007

This paper documents the occurrence of form variability through diminutive ‘wordplay’, and examines whether this variability facilitates or hinders morphology acquisition in a richly inflected language. First, in a longitudinal speech corpus of eight Russian mothers conversing with their children (1.6–3.6), and with an adult, the use of diminutive word forms was shown to be pervasive in Russian child‐directed, but not adult‐directed speech. Importantly, all of the mothers were shown to routinely engage in alternating uses of diminutive and simplex forms of the same nouns within the same conversational episodes. Second, an elicitation experiment was conducted which tested 24 children's (2.7–4.2) productivity in inflecting novel nouns for case. By varying whether children heard the novel nouns in diminutive form, simplex form or both, we show that children benefit from the introduction of words in multiple forms (i.e. showing fewer case‐marking errors in this condition). We suggest that pragmatically motivated form variation in child‐directed speech (CDS) may have beneficial effects for acquiring richly inflected languages.
Favourable and unfavourable conditions for children's confidence judgments
Authors: Roebers Claudia M. , von der Linden Nicole , Howie Pauline
Published: February 2007

Two studies are presented in which favourable and unfavourable conditions for children's meta‐cognitive monitoring processes are examined. Previously reported findings have shown that especially children's uncertainty monitoring (in contrast to certainty monitoring) poses specific problems for children in their elementary school years. When interviewing children about an observed event, answerable and unanswerable questions in two question formats (unbiased and misleading) were used, and 8‐ and 10‐year‐old children as well as adults were asked to rate their confidence on a three‐point scale concerning each response. Results of Study 1 show that accuracy instructions and the option to answer with ‘I don't know’ inflate children's level of confidence because uncertain answers are withheld. Results of Study 2 revealed that children's difficulty with uncertainty monitoring may lie in a cognitive overload during the interview because immediate confidence judgments were less precise and less adequate compared with delayed confidence judgments. Participants' rating of their uncertainty after having erroneously provided an answer to an unanswerable question proved that children aged 8 years and older are able to experience and report levels of uncertainty but, as was shown for answerable questions, these emerging competencies are dependent on favourable task conditions.
The contribution of logical reasoning to the learning of mathematics in primary school
Authors: Nunes Terezinha , Bryant Peter , Evans Deborah , Bell Daniel , Gardner Selina , Gardner Adelina , Carraher Julia
Published: February 2007

It has often been claimed that children's mathematical understanding is based on their ability to reason logically, but there is no good evidence for this causal link. We tested the causal hypothesis about logic and mathematical development in two related studies. In a longitudinal study, we showed that (a) 6‐year‐old children's logical abilities and their working memory predict mathematical achievement 16 months later; and (b) logical scores continued to predict mathematical levels after controls for working memory, whereas working memory scores failed to predict the same measure after controls for differences in logical ability. In our second study, we trained a group of children in logical reasoning and found that they made more progress in mathematics than a control group who were not given this training. These studies establish a causal link between logical reasoning and mathematical learning. Much of children's mathematical knowledge is based on their understanding of its underlying logic.
Admission Temperature of Low Birth Weight Infants: Predictors and Associated Morbidities
Authors: Laptook Abbot R. , Salhab Walid , Bhaskar Brinda ,   and the Neonatal Research Network
Published: February 2007

BACKGROUND. There is a paucity of information on the maintenance of body temperature at birth for low birth weight infants.

OBJECTIVES. We examined the distribution of temperatures in low birth weight infants on admission to the NICUs in the Neonatal Research Network centers and determined whether admission temperature was associated with antepartum and birth variables and selected morbidities and mortality.

METHODS. Infants without major congenital anomalies born during 2002 and 2003 with birth weights of 401 to 1499 g who were admitted directly from the delivery room to the NICU were included. Bivariate associations between antepartum/birth variables and admission temperature and selected morbidities/mortality and admission temperature were examined, followed by multivariable linear or logistic regressions to detect independent associations.

RESULTS. There were 5277 study infants and the mean (±SD) birth weight and gestational age were 1036 ± 286 g and 28 ± 3 weeks, respectively. The distribution of admission temperatures was 14.3% at <35°C, 32.6% between 35 and 35.9°C, 42.3% between 36 and 36.9°C, and 10.8% at ≥37°C. The estimate of birth weight on admission temperature with and without intubation was +0.13°C and +0.04°C per 100-g increase in birth weight, respectively. The mean admission temperature for each center varied from 1.5°C below to 0.3°C above a reference center. On adjusted analyses, admission temperature was inversely related to mortality (28% increase per 1°C decrease) and late-onset sepsis (11% increase per 1°C decrease) but not to intraventricular hemorrhage, necrotizing enterocolitis, or duration of conventional ventilation.

CONCLUSIONS. Preventing decreases in temperature at birth among low birth weight infants remains a challenge. Associations with intubation and center of birth suggest that assessment of temperature control for infants intubated in the delivery room may be beneficial. Whether the admission temperature is part of the casual path or a marker of mortality needs additional study.
Cognitive Transfer Revisited: Can We Exploit New Media to Solve Old Problems on a Large Scale?
Authors: Derry Sharon J. , Hmelo-Silver Cindy E. , Nagarajan Anandi , Chernobilsky Ellina , Beitzel Brian D.
Published: February 2007

The work we report in this special issue attempted to exploit the power of technology and cognitive theory to help make conceptual systems taught in large college courses truly useful in students' future lives. Facing evidence that traditional instructional models have not succeeded in this regard, we sought feasible course designs and computer-based tools that would close the gap between classrooms and practice. Using a tool for online course building that we developed during the course of our work, we designed and examined alternative theory-based instructional models that systematically integrated video case study with collaborative problem-based and text-based learning. The contexts of our research were online learning science courses for teachers taught at UW-Madison and Rutgers University. Our contribution summarizes findings from several years of design research and offers evidence concerning the strengths and limitations of the instructional model that evolved during our work. As part of our model, we have created cognitive tools to support collaborative learning by providing video cases as shared contexts and collaboration spaces and activity structures for students to share information, compare perspectives, and engage in collaborative design.
Is There Life without Work?
Authors: Nuttman-Shwartz Orit
Published: February 2007

The present study examined the way retirees perceive retirement and continue to work post-retirement. Using a longitudinal design, qualitative and quantitative analyses were performed to examine the effect of preoccupation with work on adjustment to retirement. The findings indicate a wide range of attitudes toward cessation of the working life on the eve of retirement. In addition, most retirees reported increased well-being and decreased distress one year after retirement. Although for all participants a correlation was found between adjustment and preoccupation with work on the eve of retirement, no difference in the adjustment measures emerged a year later between those who were fully retired and those who continued to work. The implications of the findings for both personal well-being and social policy are discussed.
The Use of Pathos in Charity Letters: Some Notes toward a Theory and Analysis
Authors: Myers Marshall
Published: February 2007

Americans contribute $240 billion dollars to charities each year, raised in part by writing letters to potential donors. While it is debatable what the reasons are for donors to give so much money, most donors seem to be moved to contribute by pathos, particularly pity. The concept of pathos as a rhetorical appeal has become more complex over the years, growing from a simple strategy to a complicated set of parameters requiring careful delineation. Beginning with the Greeks, particularly Aristotle, pathos was defined with greater clarity (especially the concept of enargia), with Aristotle's formal definitions of the emotions, and with the use of an image upon which to direct the audience's pity. Cicero adds to the theory by calling for the use of pathos in the peroration and reinforcing Aristotle's emphasis on careful audience analysis. St. Augustine and those who follow, including Renaissance, 18th-century rhetoricians, and 20th-century scholars like Kenneth Burke, argue that style can also be an effective persuasive strategy for a pathetic appeal. Accordingly, the charity letters examined illustrate not only Aristotle's and Cicero's tenets but also show that elements of style, particularly rhetorical figures and schemes, are common rhetorical strategies used in these charity letters. While at first the rhetoric of charity letters seems simple and straight-forward, to raise billions of dollars every year charity letters use sophisticated appeals to pity that have a long and interesting history.
Preventing Suicide by Educating General Practitioners
Authors: Zonda Tamas , Lester David
Published: February 2007

An education program for GPs about treating patients with depressive disorders and panic disorders was implemented in one district in the year 1998. A neighboring district was used as a control. Although the educational program was followed by an increase in referrals for panic disorder in the target district, there was no impact on referrals for depressive disorders, the prescribing of antidepressants by the GPs, or the suicide rate.
Attitudes on Using Pair-Programming
Authors: Howard Elizabeth V.
Published: February 2007

During a research study conducted over four semesters, students enrolled in an introductory programming class at a commuter campus used the pair-programming approach for both in-class labs and out-of-class programming assignments. This study was a comprehensive assessment of pair-programming using multiple measures of both quantitative and qualitative feedback about students' experiences with pair-programming. The results show that overwhelmingly, students reported positive reactions to working with a partner using the pair-programming paradigm. As expected at a commuter campus, the most common challenge students reported was difficulty of coordinating schedules. This article provides the results of the study and offers suggestions for managing pair-programming on a commuter campus.
An Introduction to Multilevel Modeling for Research on the Psychology of Art and Creativity
Authors: Silvia Paul J.
Published: February 2007

This article introduces some applications of multilevel modeling for research on art and creativity. Researchers often collect nested, hierarchical data—such as multiple assessments per person—but they typically ignore the nested data structure by averaging across a level of data. Multilevel modeling, also known as hierarchical linear modeling and random coefficient modeling, enables researchers to test old hypotheses more powerfully and to ask new research questions. After describing the logic of multilevel analysis, the article illustrates three practical uses of multilevel modeling: (1) estimating within-person relationships, (2) examining between-person differences in within-person processes, and (3) comparing people's judgments to a criterion. The breadth, flexibility, and power of multilevel modeling make it a useful analytic tool for the multilevel data that researchers have been collecting all along.
Three Years of Evaluating Community Tobacco Prevention Coalitions: Lessons Learned
Authors: Reinert Bonita , Carver Vivien , Range Lillian M. , Pike Chris
Published: February 2007

Though challenging, evaluation is essential for successful coalitions. In three years of annual evaluations of 30 tobacco prevention coalitions, lessons learned involve contracts, people (leaders, board members, oversight staff), and entire coalitions. Contracts should adjust within limits, include all work requirements, promote networking, and link directly to evaluation. Leaders need quarterly meetings and no numbers assigned to their performance. Board members, even youth, must be involved. Program monitors need practical or public health experience to provide encouragement with firmness. Fiscal monitors need financial acuity, fair-mindedness, communication skills, and a firm contract foundation. Program evaluators need people skills, program evaluation experience, and a coalition history. Coalitions improve nonlinearly, with awareness activities diminishing and programmatic activities increasing, so evaluation should evolve also. Oversight agencies are influential, so should restrain from introducing many new requirements and avoid blindsiding leaders. Best evaluations are cooperative, collegial dialogs between evaluator(s) and the entire coalition.