bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomechanics of the rostrum and the role of facial sutures
Authors: Rafferty Katherine L. , Herring Susan W. , Marshall Christopher D.
Published: May 2003

The rostrum is a large diameter, thin‐walled tubular structure that receives loads from the teeth. The rostrum can be conceptualized both as a rigid structure and as an assemblage of several bones that interface at sutures. Using miniature pigs, we measured in vivo strains in rostral bones and sutures to gain a better understanding of how the rostrum behaves biomechanically. Strains in the premaxillary and nasal bones were low but the adjacent maxillary‐premaxillary, internasal, and intermaxillary suture strains were larger by an order of magnitude. While this finding emphasizes the composite nature of the rostrum, we also found evidence in the maxillary and nasal bones for rigid structural behavior. Namely, maxillary strain is consistent with a short beam model under shear deformation from molar loading. Strain in the nasal bones is only partially supported by a long beam model; rather, a complex pattern of dorsal bending of the rostrum from incisor contact and lateral compression is suggested. Torsion of the maxilla is ruled out due to the bilateral occlusion of pigs and the similar working and balancing side strains, although it may be important in mammals with a unilateral bite. Torsional loading does appear important in the premaxillae, which demonstrate working and balancing side changes in strain orientation. These differences are attributed to asymmetrical incisor contact occurring at the end of the power stroke. J. Morphol. 257:33–44, 2003. © 2003 Wiley‐Liss, Inc.
Involvement of the gonadal germinal epithelium during sex reversal and seasonal testicular cycling in the protogynous swamp eel, synbranchus marmoratus Bloch 1795 (teleostei, synbranchidae)
Authors: Lo Nostro F. , Grier H. , Andreone L. , Guerrero G.A.
Published: May 2003

The swamp eel, Synbranchus marmoratus, is a protogynous, diandric species. During sex reversal, the ovarian germinal epithelium, which forms follicles containing an oocyte and encompassing follicle cells during the female portion of the life cycle, produces numerous invaginations, or acini, into the ovarian stroma. Within the acini, the gonia that formerly produced oocytes become spermatogonia, enter meiosis, and produce sperm. The acini are bounded by the basement membrane of the germinal epithelium. Epithelial cells of the female germinal epithelium, which formerly became follicle (granulosa) cells, now become Sertoli cells in the developing testis. Subsequently, lobules and testicular ducts form. The swamp eel testis has a lobular germinal compartment in both primary and secondary males, although the germinal compartment in testes of secondary males resides within the former ovarian lamellae. The germinal compartment, supported by a basement membrane, is composed of Sertoli and germ cells that give rise to sperm. Histological and immunohistochemical techniques were used to describe the five reproductive classes that were observed to occur during the annual reproductive cycle: regressed, early maturation, mid‐maturation, late maturation, and regression. These classes are differentiated by the presence of continuous or discontinuous germinal epithelia and by the types of germ cells present. Synbranchus marmoratus has a permanent germinal epithelium. Differences between the germinal compartment of the testes of primary and secondary males were not observed. J. Morphol. 257:107–126, 2003. © 2003 Wiley‐Liss, Inc.
Morphology and histochemistry of the peripheral olfactory organ in the round goby, Neogobius melanostomus (Teleostei: Gobiidae)
Authors: Belanger Rachelle M. , Smith Cortney M. , Corkum Lynda D. , Zielinski Barbara S.
Published: May 2003

This first comprehensive study of the peripheral olfactory organ from a representative of the large and economically important order of teleost fishes, the Perciformes, shows a compact structure with olfactory sensory neurons distributed widely throughout the olfactory chamber. The spatial organization of the nasal cavity in the bottom‐dwelling round goby (Gobiidae, Neogobius melanostomus) was examined using impression material injection, immunocytochemistry, and transmission electron microscopy. The olfactory chamber contains a single olfactory lamella; prominent dorsocaudal lachrymal and ethmoidal accessory nasal sacs are situated ventrocaudal to the chamber. The location of the olfactory mucosa within the olfactory chamber is novel for teleost fish, as it extends beyond the ventral surface to the lateral and dorsal regions. Microvillar olfactory sensory neurons and ciliated olfactory sensory neurons were identified by transmission electron microscopy and the spatial distribution of these two cell types was assessed through immunocytochemistry against olfactory receptor coupled G‐proteins. Both Gαolf‐immunoreactive ciliated olfactory sensory neurons and the Gαo‐immunoreactive microvillar form were located throughout the olfactory epithelium. Ciliated crypt cells were Gαo immunoreactive and were found throughout the olfactory epithelium of some specimens. The widespread occurrence of olfactory sensory neurons in the olfactory chamber supports the idea that olfactory signaling is important to the survival of the round goby. The prominence of the lachrymal and ethmoidal accessory nasal sacs indicates the capacity to regulate the flow of odorant molecules over the sensory surface of the olfactory sensory neurons, possibly through a pump‐like mechanism driven by opercular activity associated with gill ventilation. J. Morphol. 257:62–71, 2003, © 2003 Wiley‐Liss, Inc.
Spatial expression patterns of skin‐type antifreeze protein in winter flounder (Pseudopleuronectes americanus) epidermis following metamorphosis
Authors: Murray Harry M. , Hew Choy L. , Fletcher Garth L.
Published: May 2003

Two isotypes of Type I antifreeze protein (AFP), the liver‐type and the skin‐type, have been described from adult winter flounder (Pseudopleuronectes americanus). Although the liver‐type AFP has been well studied, the skin‐type has just begun to be characterized. It appears to have a wide tissue distribution, be expressed constitutively, and the absence of a signal sequence suggests it is active intracellularly. The current study was designed to examine the onset of skin‐type AFP expression during the thickening of the epidermis at metamorphosis from both the nucleic acid and protein levels. The epidermis appeared as a thin layer overlying a thickened dermis at metamorphosis and showed a gradual increase in thickness through the first fall and winter. The onset of skin‐type antifreeze expression occurred in conjunction with this epidermal thickening. In situ hybridization and immunohistochemistry showed a distribution of mRNA and skin‐type AFP specific for the epidermis and epidermal pavement cells. The AFP immunoproduct showed a distribution intimate with the pavement cell membrane and through the interstitial spaces. This distribution suggests that the AFP may be important in slowing ice crystal formation in these interstitial regions and thus reducing cellular damage due to osmotic imbalance. J. Morphol. 257:78–86, 2003. © 2003 Wiley‐Liss, Inc.
Structure of spermatodoses in shield‐back bushcrickets (Tettigoniidae, Tettigoniinae)
Authors: Vahed Karim
Published: May 2003

Many aspects of the reproductive anatomy and physiology of tettigoniids have been studied extensively. These include the large, externally visible spermatophores and the bundles of sperm, known as spermatodesms. However, spermatodoses, spermatophore‐like structures found within the spermatheca, seem to have been almost completely overlooked: their structure has not been described since 1913 and they have subsequently received only passing mention in the literature. Each time the female mates, a separate spermatodose is formed. Here I use photographs, from light‐microscopy, of whole and sectioned spermatodoses to describe the external and internal structure of spermatodoses of nine different genera within the subfamily Tettigoniinae. The structure of the spermatodoses is very similar for the different genera. Each spermatodose is pear‐ or onion‐shaped and consists of a thin outer layer, enclosing a thick, gelatinous inner layer. A large sperm mass occupies the bulbous end of the spermatodose, while a thin sperm‐tube leads from the sperm mass, along the center of the elongated neck of the spermatodose, and appears to exit at the pointed‐tip of the spermatodose. Feather‐like bundles of sperm (spermatodesms) were clearly visible within the sperm mass and also appeared to be present within the sperm‐tube. The wall of the sperm tube appeared to be composed of material similar to that of the outer layer of the spermatodose. Within the spermatheca, spermatodoses appeared to be stratified in that only one of them ever occupied the position nearest to the spermathecal duct. The possible function of spermatodoses is discussed: it is proposed that they have evolved as a result of sexual conflict and function to protect the sperm from being destroyed by the female while they are in storage. J. Morphol. 257:45–52, 2003. © 2003 Wiley‐Liss, Inc.
Functional morphology of extreme jaw protrusion in Neotropical cichlids
Authors: Waltzek Thomas B. , Wainwright Peter C.
Published: May 2003

The New World cichlids Petenia splendida and Caquetaia spp. possess extraordinarily protrusible jaws. We investigated the feeding behavior of extreme (here defined as greater than 30% head length) and modest jaw‐protruding Neotropical cichlids by comparing feeding kinematics, cranial morphology, and feeding performance. Digital high‐speed video (500 fps) of P. splendida, C. spectabile, and Astronotus ocellatus feeding on live guppy prey was analyzed to generate kinematic and performance variables. All three cichlid taxa utilized cranial elevation, lower jaw depression, and rotation of the suspensorium to protrude the jaws during feeding experiments. Extreme anterior jaw protrusion in P. splendida and C. spectabile resulted from augmented lower jaw depression and anterior rotation of the suspensorium. Morphological comparisons among eight cichlid species revealed novel anterior and posterior points of flexion within the suspensorium of P. splendida and Caquetaia spp. The combination of anterior and posterior loosening within the suspensorium in P. splendida and Caquetaia spp. permitted considerable anterior rotation of the suspensorium and contributed to protrusion of the jaws. Petenia splendida and C. spectabile exhibited greater ram distance and higher ram velocities than did A. ocellatus, resulting primarily from increased jaw protrusion. Petenia splendida and C. spectabile exhibited lower suction feeding performance than A. ocellatus, as indicated by lower suction‐induced prey movements and velocities. Thus, extreme jaw protrusion in these cichlids may represent an adaptation for capturing elusive prey by enhancing the ram velocity of the predator but does not enhance suction feeding performance. J. Morphol. 257:96–106, 2003. © 2003 Wiley‐Liss, Inc.
Pericardium of the frog, Rana esculenta, is morphologically designed as a lymphatic space
Authors: Cerra Maria Carmela , Amelio Daniela , Tavolaro Palmira , Palma Antonio , Marcianò Vito , Farina Felicia
Published: May 2003

The importance of the pericardium and the pericardial fluid (PF) in the control of cardiac function has emerged over the past few years. Despite the acknowledgment that amphibians are exposed to both dehydration and excessive water accumulation, nothing is known about their pericardial structure and the morphological basis of the PF formation. We have studied the parietal pericardium (PP) morphology in Rana esculenta by electron microscopy. SEM images of the inner surface, which lines the pericardial cavity, revealed the presence of large vesicles and many small circular openings. TEM observations showed that the PP is made up of an inner mesothelial lining, often constituted by two layers of very flat cells lying on a basal membrane and of regularly oriented collagen bundles. The PP outer surface is lined by a layer of flat cells, without a basal membrane. The mesothelial cells had overlapping boundaries with complex intercellular connections and a rich pool of caveolae opened in the direction of both the pericardial cavity and intercellular spaces. These cells indicate an intense intracellular and/or intercellular transfer of fluids and substances. The intraperitoneal injection of the idromineral hormone, Val5‐ANG II, induced PP modifications, particularly evident at the level of the structures involved in the transmesothelial traffic. These lymphatic‐like traits suggest that the frog PP represents a large lymphatic sac, subject to paracrine‐endocrine remodeling, which can actively adjust the PF, influencing the composition and volume of the myocardial interstitial fluid. J. Morphol. 257:72–77, 2003. © 2003 Wiley‐Liss, Inc.
A desert octodontid rodent, Tympanoctomys barrerae, uses modified hairs for stripping epidermal tissue from leaves of halophytic plants
Authors: Berman Susan L.
Published: May 2003

Desert rodents that consume halophytic plants must have adaptations for coping with the high salt content of the leaves. A kidney capable of excreting very concentrated urine is one method. Another is removal of the hypersaline epidermis by means of chisel‐like incisors prior to ingestion of the leaves. Tympanoctomys barrerae has evolved a unique refinement of the latter adaptation. It possesses two bundles of stiffened hairs on either side of the palate just caudal to the incisors. The bundles vibrate against the lower incisors, removing the epidermis from the leaves. The efficiency of the operation is significantly greater than with the use of incisors alone. Such a device has not been described in any other mammal. The facial muscles associated with the lips, the cheek vibrissae, and the oral cavity are described in T. barrerae and the nonhalophilic octodontid Octomys mimax. M. buccinatorius pars intermaxillaris is the only muscle in direct contact with the bristle bundles. Other anatomical features found in T. barrerae that may be associated with this feeding device are: 1) a much enlarged and mobile lower labial pad operated by Mm. buccinatorius pars orbicularis oris, pars longitudinalis profunda, and mandibularis cranialis profunda; 2) two oral glands not described in other rodents; and 3) a shortened tongue. Although, taken as a whole, this epidermal stripping device is unique to T. barrerae, most of its features have evolved by modification of structures present in the facial region of more generalized rodents. J. Morphol. 257:53–61, 2003. © 2003 Wiley‐Liss, Inc.
Australian drought: the interference of multi‐spectral global standing modes and travelling waves
Authors: White Warren B. , McKeon Greg , Syktus Jozef
Published: May 2003

Extreme drought has devastated the flora, fauna, and regional economy in rangeland grazing districts over Australia for 3–5 years duration every 20 to 30 years throughout the 20th century. We investigate the source of drought occurring in five example grazing districts in eastern and central Australia. We find year‐to‐year variability in grazing district rainfall (GDR) during the summer rainy season (November to March) composed of quasi‐biennial, interannual, quasi‐decadal, and interdecadal signals from 1900 to 1999. However, the longer period signals dominate, accounting for the interdecadal quasi‐periodicity of the drought/flood cycle. We find these GDR signals associated with corresponding global standing modes and travelling waves in covarying sea‐surface temperature (SST) and sea‐level pressure (SLP) anomalies. These global SST/SLP modes/waves influence the GDR signals by altering the troposphere moisture flux converging onto the grazing districts from regional tropical and extra‐tropical oceanic source regions. We construct statistical models to determine whether the evolution of these global SST/SLP modes/waves over the oceanic source regions can hindcast corresponding GDR signals from one year to the next. When these models allow for modulation of the modes/waves, they hindcast ∼1/3 of the variance in the GDR indices at 1 year lead, including the drought episodes. We find drought resulting from the constructive interference of the dry phases of the quasi‐decadal and interdecadal global SST/SLP modes/waves, accompanied by a weakening of year‐to‐year variability associated with either weak quasi‐biennial and interannual modes/waves or their destructive interference. Copyright © 2003 Royal Meteorological Society
Simulation of impact of projected climate change on wheat in India
Authors: Attri S. D. , Rathore L. S.
Published: May 2003

The problem of global climate change due to natural processes and anthropogenic sources and its impacts on world food security in general and its regional impacts in particular have come to forefront of the scientific community in recent years. Though the uncertainty of projected climate change at the regional level is higher, it is still necessary to assess its impacts on crop productivity for formulating response strategies. Climate change scenarios projected by the middle of the current century, based on the latest studies, were created and the impacts of concurrent changes of temperature and CO2 on the growth, development and yields of wheat in northwest India were quantified using a state‐of‐the‐art dynamic simulation model. Yield enhancements of the order of 29–37% and 16–28% under rainfed and irrigated conditions respectively in different genotypes were observed under a modified climate (Tmax + 1.0°C, Tmin + 1.5°C, 2 × CO2). Any further increase beyond 3 °C cancelled the beneficial impact of enhanced CO2.

Adaptation measures to mitigate the potential impact of climate change included possible changes in sowing dates and genotype selection. Enhancement of sowing by 10 days in late‐sown cultivars and delaying of sowing by 10 days in normally sown cultivars resulted in higher yields under a modified climate, whereas a reduction in yield was observed in the reverse strategies. Copyright © 2003 Royal Meteorological Society
Responses of China's summer monsoon climate to snow anomaly over the Tibetan Plateau
Authors: Qian Y. F. , Zheng Y. Q. , Zhang Y. , Miao M. Q.
Published: May 2003

The climatological features of the winter snow depth over the Tibetan Plateau and the summer precipitation in China are diagnosed using datasets obtained from 78 snow observation stations and 160 rainfall stations during 1957 to 1998. The climatic effects of the snow anomaly over the Tibetan Plateau on the regional summer monsoon climate in China are diagnosed and numerically simulated by use of a regional climate model (RegCM2). The singular value decomposition technique is adopted to diagnose the relationships between the previous winter and spring plateau snow depth anomalies and the spring and summer regional precipitation in China. It is found that the snow depth anomaly, especially in winter, is one of the factors influencing precipitation in China; however, it is perhaps not the only one, and even not the most important one. Nevertheless, it is proved that the winter snow anomaly over the Tibetan Plateau is relatively more important than that in spring for the regional precipitation in China. Results of numerical simulations show that the snow anomaly over the plateau has effects that are evident on China's summer monsoon climate. The increase of both snow cover and snow depth can delay the onset and weaken the intensity of the summer monsoon obviously, resulting in a decrease in precipitation in southern China and an increase in the Yangtze and Huaihe River basins. The influence of the winter snow depth is more substantial than that of both the winter snow cover and the spring snow depth. The mechanism of how the plateau snow anomaly influences the regional monsoon climate is briefly analysed. It is found that snow anomalies over the Tibetan Plateau change the soil moisture and the surface temperature through the snowmelt process at first, and subsequently alter heat, moisture and radiation fluxes from the surface to the atmosphere. Abnormal circulation conditions induced by changes of surface fluxes may affect the underlying surface properties in turn. Such a long‐term interaction between the wetland and the atmosphere is the key process resulting in later climatic changes. Copyright © 2003 Royal Meteorological Society
Spring northward retreat of Eurasian snow cover relevant to seasonal and interannual variations of atmospheric circulation
Authors: Ueda Hiroaki , Shinoda Masato , Kamahori Hirotaka
Published: May 2003

An observational study is made of the seasonal and interannual variations of spring snow‐disappearance over the Eurasian continent and the circulation mechanisms causing those variations. The spring northward retreat of the snow boundary over the East European Plain (EEP) between 30 and 60° E is faster (0.4° per day) than to the east of the Ural Mountain range (0.3° per day). These migrations of the snow boundary lag behind the appearance of the surface air temperature 0 °C by about 1 to 5 pentads.

The analyses of the atmospheric heat and moisture budgets showed that the seasonal intrusion of warm air associated with southwesterly winds is primarily responsible for the rapid snowmelt in March and April over the EEP. In addition, the adiabatic heating of descending air plays a secondary role in the snowmelt in mid‐March. On an interannual time scale, horizontal warm advection also plays an essential role in the spring northward retreat of snow cover extent.

The present study confirms the previous finding that the surface air temperature anomalies, produced during the seasonal snow‐disappearance period, diminished in May, suggesting a weak dynamical linkage between the EEP snow cover and Asian summer monsoon. Copyright © 2003 Royal Meteorological Society
Sea‐surface temperature co‐variability in the Southern Atlantic and Indian Oceans and its connections with the atmospheric circulation in the Southern Hemisphere
Authors: Fauchereau N. , Trzaska S. , Richard Y. , Roucou P. , Camberlin P.
Published: May 2003

The relationship between sea‐surface temperature (SST) inter‐annual variability at the subtropical and midlatitudes of the southern Atlantic and Indian Oceans and its links with the atmospheric circulation in the Southern Hemisphere are investigated over the 1950–1999 period. Exploratory analysis using singular value decomposition and further investigations based on simple indices show that a large part of regional SST variability is common between the southwestern parts of both basins at subtropical and midlatitudes during the austral summer. Interestingly, these areas are also significantly associated with the far southwestern Pacific (Tasman Sea area). The patterns and time series of co‐variability between the southern Atlantic and Indian Oceans are shown to correspond to SST modes previously described in the literature as ‘subtropical dipoles’, independently for the Atlantic and Indian Oceans. Composite analyses show that austral summers characterized by simultaneous warm (and to a lesser extent cold) SST anomalies in the southwestern (northern) part of both southern oceans are related to atmospheric anomalies mainly involving a southward shift and a strengthening of the subtropical high‐pressure systems over both basins. These anomalies are embedded in a hemispheric signal associating two cores of positive pressure anomalies within the South Pacific anticyclone. The global picture appears to have a wave number 4 spatial structure. The associated low‐level wind and latent heat‐flux anomalies and the lags between atmospheric variables and SST anomalies are consistent with an atmospheric forcing on the ocean. Potential links of these patterns with large‐scale modes of climate variability in the Southern Hemisphere are discussed. Copyright © 2003 Royal Meteorological Society.
Homogeneity of 20th century European daily temperature and precipitation series
Authors: Wijngaard J. B. , Klein Tank A. M. G. , Können G. P.
Published: May 2003

Daily European station series (1901–99) of surface air temperature and precipitation from the European Climate Assessment dataset are statistically tested with respect to homogeneity. A two‐step approach is followed. First, four homogeneity tests are applied to evaluate the daily series. The testing variables used are (1) the annual mean of the diurnal temperature range, (2) the annual mean of the absolute day‐to‐day differences of the diurnal temperature range and (3) the wet day count (threshold 1 mm). Second, the results of the different tests are condensed into three classes: ‘useful’, ‘doubtful’ and ‘suspect’. A qualitative interpretation of this classification is given, as well as recommendations for the use of these labelled series in trend analysis and variability analysis of weather extremes. In the period 1901–99, 94% of the temperature series and 25% of the precipitation series are labelled ‘doubtful’ or ‘suspect’. In the sub‐period 1946–99, 61% of the temperature series and 13% of the precipitation series are assigned to these classes. The seemingly favourable scores for precipitation can be attributed to the high standard deviation of the testing variable, and hence the inherent restricted possibilities for detecting inhomogeneities. About 65% of the statistically detected inhomogeneities in the temperature series labelled ‘doubtful’ or ‘suspect’ in the period 1946–99 can be attributed to observational changes that are documented in the metadata. For precipitation this percentage is 90%. Copyright © 2003 Royal Meteorological Society
Photoinduced Charge Separation in an Aqueous Phase Using Nanoporous TiO2 Film and a Quasi‐Solid Made of Natural Products
Authors: Kaneko Masao , Nomura Tomoyo , Sasaki Chie
Published: May 2003

Solar cells comprised of nanoparticulate TiO2 porous film photosensitized with an adsorbing dye have been utilized as photoinduced charge separation systems in aqueous media with the view to forming future artificial photosynthetic systems able to create fuels from solar energy and water. The photoinduced charge separation of the sensitized TiO2 cell in a quasi‐solid, made from agarose or κ‐carrageenan, was investigated.

I–V curves under 98 mW · cm−2 irradiation of ITO/TiO2/Ru(dcbpy)2(NCS)2. Electrolyte: 0.1 M LiI/0.01 M I2 in a quasi‐solid of 0.2 wt.‐% gelatin containing a large excess of water.

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I–V curves under 98 mW · cm−2 irradiation of ITO/TiO2/Ru(dcbpy)2(NCS)2. Electrolyte: 0.1 M LiI/0.01 M I2 in a quasi‐solid of 0.2 wt.‐% gelatin containing a large excess of water.
Temperature‐Sensitive Poly(N‐isopropylacrylamide) Hydrogels with Macroporous Structure and Fast Response Rate
Authors: Zhang Jian‐Tao , Cheng Si‐Xue , Huang Shi‐Wen , Zhuo Ren‐Xi
Published: May 2003

Macroporous temperature‐sensitive poly(N‐isopropylacrylamide) (PNIPA) hydrogels were prepared by a novel phase‐separation technique to improve the response properties. In comparison with a conventional PNIPA hydrogel prepared in water, these macroporous hydrogels, prepared by polymerization in aqueous sucrose solutions, have higher swelling ratios at temperatures below the lower critical solution temperature and exhibit much faster response rates to temperature changes.

Scanning electron microscopy image of the surface of a PNIPA hydrogel, prepared in 1.50 M aqueous sucrose solution.

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Scanning electron microscopy image of the surface of a PNIPA hydrogel, prepared in 1.50 M aqueous sucrose solution.
Highly Defined ABC Triblock Cooligomers and Copolymers Prepared by ROMP Using an N‐Heterocyclic‐Carbene‐Substituted Ruthenium Benzylidene Initiator
Authors: Slugovc Christian , Riegler Silvia , Hayn Gertraud , Saf Robert , Stelzer Franz
Published: May 2003

The “3rd generation Grubbs” initiator (H2IMes)(3‐bromopyridine)2(Cl)2RuCHPh (1) accomplishes the synthesis of ABC triblock copolymers via living ring‐opening metathesis polymerisation (ROMP) of norbornene derivatives. Complete initiation and an outstanding tolerance of functional groups are provided, which is proven by a combined study by means of matrix‐assisted laser desorption/ionisation mass spectrometry, gel permeation chromatography and NMR spectroscopy on an ABC triblock cooligomer.

Gel permeation chromatograms of oligoA, oligoAB, and oligoABC.

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Gel permeation chromatograms of oligoA, oligoAB, and oligoABC.
Synthesis of a New Thiophene/Quinoxaline CT‐Type Copolymer with High Solubility and Its Basic Optical Properties
Authors: Yamamoto Takakazu , Lee Ban‐Lin , Kokubo Hisashi , Kishida Hideo , Hirota Keisuke , Wakabayashi Takeru , Okamoto Hiroshi
Published: May 2003

A new π‐conjugated charge‐transfer‐type copolymer of electron‐donating thiophene and electron‐accepting quinoxaline was prepared by organometallic polycondensation. The polymer was soluble in organic solvents such as tetrahydrofuran, and showed a UV‐vis peak at long wavelengths of 598 nm in chloroform and 629 nm in the film. Its film exhibited a χ(3) peak in the resonance region with a χ(3) value comparable to that of regioregular head‐to‐tail poly(3‐hexylthiophene‐2,5‐diyl).

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Well‐Controlled Biodegradable Nanocomposite Foams: From Microcellular to Nanocellular
Authors: Fujimoto Youhei , Ray Suprakas Sinha , Okamoto Masami , Ogami Akinobu , Yamada Kazunobu , Ueda Kazue
Published: May 2003

Via a batch process in an autoclave, the foam processing of neat polylactide (PLA) and two different types of PLA/layered silicate nanocomposites has been conducted using supercritical carbon dioxide as a foaming agent. The morphological correlation between the dispersed silicate particles with nanometer dimensions in the bulk and the obtained closed‐cell structure of the foam is discussed. This is the first report that deals with the possibility of preparing biodegradable nanocellular polymeric foams via nanocomposite technology.

SEM image of the freeze‐fracture surface of a PLA/layered silicate foam, exhibiting closed‐cell structure.

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SEM image of the freeze‐fracture surface of a PLA/layered silicate foam, exhibiting closed‐cell structure.
Spatially Confined Tungstate Ion Polymerization in Microcapsules
Authors: Shchukin Dmitry G. , Dong Wenfei , Sukhorukov Gleb B.
Published: May 2003

A new approach for performing the WO42− polymerization reaction exclusively inside polyelectrolyte capsules of a micron scale size is demonstrated. This approach is based upon a pH gradient across the capsule shell (2.5 inside the capsule volume and 6.5 outside the capsule) caused by encapsulated poly(styrene sulfonate) molecules. During the first stage of the reaction, different polytungstate anions were synthesized. Crystalline WO3 nanoparticles were formed inside the capsule as the final polymerization product.

The tungstate ion polymerization confined within a micron‐sized polyelectrolyte capsule described herein.

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The tungstate ion polymerization confined within a micron‐sized polyelectrolyte capsule described herein.
Enzyme‐Catalyzed Preparation of Aliphatic Polyesters Containing Thioester Linkages
Authors: Iwata Shin , Toshima Kazunobu , Matsumura Shuichi
Published: May 2003

Aliphatic polyesters containing thioester linkages were enzymatically prepared by both the copolymerization of lactone with mercaptoalkanoic acid and by the transesterification of polyesters with mercaptoalkanoic acids. The enzymatic copolymerization of ε‐caprolactone with 11‐mercaptoundecanoic acid (11MU) and 3‐mercaptopropionic acid (3MP) was performed under reduced pressure using an immobilized lipase from Candida antarctica (CA). The transesterification of poly(ε‐caprolactone) and poly[(R)‐3‐hydroxybutyrate] was carried out with 11MU and 3MP using lipase CA under reduced pressure.

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Ethylene and Ethylene/Propylene Polymerization Behavior of Bis(phenoxy‐imine) Zr and Hf Complexes with Perfluorophenyl Substituents
Authors: Ishii Sei‐ichi , Furuyama Rieko , Matsukawa Naoto , Saito Junji , Mitani Makoto , Tanaka Hidetsugu , Fujita Terunori
Published: May 2003

The catalytic properties of bis(phenoxy‐imine) Zr and Hf complexes incorporating perfluorophenyl groups with methylaluminoxane were investigated. The fluorinated complexes produced far higher‐molecular‐weight polyethylenes and ethylene/propylene copolymers with increased activities compared with the non‐fluorinated congeners. Moreover, the fluorinated complexes displayed a higher incorporation ability for propylene.

Structures of complexes 1–4.

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Structures of complexes 1–4.
Carbon dioxide laser‐assisted nerve repair: Effect of solder and suture material on nerve regeneration in rat sciatic nerve
Authors: Menovsky Tomas , Beek Johan F.
Published: May 2003

In order to further improve and explore the role of lasers for nerve reconstruction, this study was designed to investigate regeneration of sharply transected peripheral nerves repaired with a CO2 milliwatt laser in combination with three different suture materials and a bovine albumin protein solder as an adjunct to the welding process. Unilateral sciatic nerve repair was performed in 44 rats. In the laser group, nerves were gently apposed, and two stay sutures (10‐0 nylon, 10‐0 polyglycolic acid, or 25‐μm stainless steel) were placed epi/perineurially. Thereafter, the repair site was fused at 100 mW with pulses of 1.0 s. In the subgroup of laser‐assisted nerve repair (LANR), albumen was used as a soldering agent to further reinforce the repair site. The control group consisted of nerves repaired by conventional microsurgical suture repair (CMSR), using 4–6 10‐0 nylon sutures. Evaluation was performed at 1 and 6 weeks after surgery, and included qualitative and semiquantitative light microscopy. LANR performed with a protein solder results in a good early peripheral nerve regeneration, with an optimal alignment of nerve fibers and minimal connective tissue proliferation at the repair site. All three suture materials produced a foreign body reaction; the least severe was with polyglycolic acid sutures. CMSR resulted in more pronounced foreign‐body granulomas at the repair site, with more connective‐tissue proliferation and axonal misalignment. Furthermore, axonal regeneration in the distal nerve segment was better in the laser groups. Based on these results, CO2 laser‐assisted nerve repair with soldering in combination with absorbable sutures has the potential of allowing healing to occur with the least foreign‐body reaction at the repair site. Further experiments using this combination are in progress. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:109–116 2003
Two‐stage reconstruction of four‐digit amputation: Distal ulnar artery flap and combined second‐ and third‐toe transfer
Authors: Yıldız Mehmet , Şener Muhittin , Turgutoğlu Olcay , Baki Celål
Published: May 2003

We report a case of combined two toe transfer after distal ulnar artery fasciocutaneous flap in a 10‐year‐old boy who has four‐digit amputation. Four years after the operation, satisfactory results were obtained both functionally and cosmetically. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:103–104 2003
Retrograde arterialized venous flap: An experimental study
Authors: Moshammer Harald E.T. , Schwarzl Franz X. , Haas Franz M. , Maechler Heinrich , Pierer Gerhard , Wiltgen Marco , Koch Horst
Published: May 2003

An experimental model was established to study circulation in retrograde arterialized venous flaps (RAVF). Venous flaps measuring 7 × 4 cm with a matching venous system were harvested from both forearms of 10 fresh human cadavers. In each trial, both flaps were simultaneously perfused with heparinized human blood driven by a pulsatile circulation model. In each trial there was one flap with retrograde perfusion, and one flap with antegrade perfusion. Clinical assessment, measurement of outflow, and angiographic examination with digitally assisted assessment after 3 h of perfusion showed better results for retrograde perfusion in 8 of the 10 trials. This study indicates that blood circulation in the periphery of arterialized venous flaps can be enhanced by retrograde arterialization. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:130–134 2003
New model for simultaneous heart and kidney transplantation in mice
Authors: Wang Minghui , Bai Jie , Baumann Marcus , Heemann Uwe
Published: May 2003

In clinical settings, combined heart and kidney transplantation results in a lower incidence of cardiac graft and renal graft rejection as compared to isolated heart and kidney transplantation. To study the phenomenon in an experimental setting, we developed a model of combined heart and kidney transplantation in mice. According to our technique, we kept the patch of the infrarenal aorta and inferior vena cava (IVC) as long as possible during the donor's kidney explantation, and then, after finishing the kidney implantation with conventional techniques, we anastomosed the innominate artery and pulmonary artery of the heart graft to the patch of the infrarenal aorta and IVC of the renal graft, respectively, instead of the recipient's aorta and IVC. With the use of our method, combined heart and kidney transplantation in mice can be performed to get enough suture room for the second graft, to avoid prolonging the occlusion time of the recipient's circulation, and to profoundly decrease postoperative complications such as paraplegia and mortality. Of the 14 recipients with combined heart‐kidney isografting, 10 have been successful (71.4%), surviving over 100 days with normal function of both grafts, and with lack of change in histological appearance. This suggests that the technique is feasible and reliable. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:164–168 2003
NMR analysis of biindenylidenes
Authors: Spiteller Peter , Jovanovic Jovan , Spiteller Michael
Published: May 2003

The 1H and 13C NMR parameters (chemical shifts and coupling constants) were determined of four biindenylidene isomers, (E)‐2,3,2′,3′‐tetrahydro‐[1,1′]biindenylidene, (Z)‐2,3,2′,3′‐tetrahydro‐[1,1′]biindenylidene, 1,3,1′, 3′‐tetrahydro‐[2,2′]biindenylidene and 2,3,1′,3′‐tetrahydro‐[1,2′]biindenylidene. Copyright © 2003 John Wiley & Sons, Ltd.
Electronic structure of thiazides studied by 35Cl‐NQR spectroscopy and DFT calculations
Authors: Latosińska J. N.
Published: May 2003

NQR frequencies were determined for the 35Cl isotope in a few benzodithiazine derivatives, chlorothiazide (CTZ), hydrochlorothiazide (HCTZ), althiazide (ATZ), trichloromethiazide (TCTZ), benzthiazide (BTZ) and furosemide (FSE), at liquid nitrogen and room temperatures. It was found that changes of the substituent at C‐3 are transferred through a system of coupled rings on to the chlorine atom at C‐6. The substituents occurring in thiazides can be ordered according to increasing electron‐acceptor properties as —CH2SCH2Ph < —CH2SCH2CHCH2 <—CHCl2. At the liquid nitrogen temperature —CH2SCH2Ph and —CH2SCH2CHCH2 are electron donors, and CHCl2 is an electron acceptor, whereas at room temperature —CH2SCH2Ph is an electron donor and —CH2SCH2CHCH2 and —CHCl2 are electron acceptors. The character of the substituent properties is preserved irrespective of whether the system is aromatic or aliphatic. The NQR frequencies and substituents properties are well reproduced by the DFT B3LYP/6–311+G(2d,p) method. The topological properties of the Laplacian of the electron density were analysed within the AIM (atoms in molecules) approach. The changes in the electron density at C‐3 are correlated with the biological activity of the compounds studied. Copyright © 2003 John Wiley & Sons, Ltd.
31P CP/MAS NMR of polycrystalline and immobilized phosphines and catalysts with fast sample spinning
Authors: Reinhard S. , Blümel J.
Published: May 2003

Cross‐polarization (CP) at fast magic angle spinning (MAS) frequencies leads to a splitting of the Hartmann–Hahn (HH) matching profile into a centerband and additional bands of higher orders. The matching profiles differ with the substance categories. Therefore, signal intensity is usually lost, when e.g. the routine standard NH4H2PO4 is used for optimizing the 1H–31P HH match prior to measuring phosphines and their metal complexes in polycrystalline or immobilized form. Here, a variety of model compounds, such as Ph2PCH2CH2PPh2 and (CO)2Ni(PPh3)2, which can be used as 31P CP standards for analogous substances or materials are presented. Investigating the influences of MAS frequency, contact time, 1H pulse power and sample volume on the matching profiles of the model compounds leads to general trends. Thereby, a new strategy for measuring difficult samples with CP at high MAS rates has been developed: their optimum CP parameters are derived from the most intense maxima in the HH matching profiles of the corresponding model compounds. This new strategy is compared with variations of a conventional ramp sequence. Although the latter generally provide smaller signal half‐widths, the new strategy leads to higher signal intensities. The new method was successfully applied to polycrystalline and immobilized phosphines and catalysts. Copyright © 2003 John Wiley & Sons, Ltd.
A selective pulse sequence for the determination of long‐range C,H spin coupling constants
Authors: Findeisen M. , Berger S.
Published: May 2003

A new pulse sequence for determining scalar long range C,H spin couplings in small organic molecules is proposed. It is based on the combination of a selective J‐resolved spectrum with a selective HMBC and displays the long‐range spin couplings of one chosen carbon atom in the indirect dimension. Advantages and disadvantages are discussed on example spectra of ethanol, strychnine and sucrose. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis and spectral study of a novel distamycin conjugate
Authors: Pineda de las Infantas M. J. , Campos J. , Baraldi P. G. , Romagnoli R. , Gallo M. A. , Espinosa A.
Published: May 2003

The 1H and 13C NMR resonances for a novel distamycin conjugate, 3‐[1‐methyl‐4‐[1‐methyl‐4‐[1‐methyl‐4‐[N1‐[5‐methyl‐2,4(1H,3H)pyrimidinedione]acetylamino]pyrrole‐2‐carboxamido]pyrrole‐2‐carboxamido]pyrrole‐2‐carboxamido]propionamidine hydrochloride (1), were assigned, using the concerted application of one‐ and two‐dimensional NMR techniques including nuclear Overhauser effect difference, DEPT, HMQC and HMBC experiments. Copyright © 2003 John Wiley & Sons, Ltd.
Solid‐state cross‐polarization magic angle spinning 13C and 15N NMR characterization of Sepia melanin, Sepia melanin free acid and Human hair melanin in comparison with several model compounds
Authors: Adhyaru Bhavin B. , Akhmedov Novruz G. , Katritzky Alan R. , Bowers Clifford R.
Published: May 2003

This paper presents the high‐resolution 13C and 15N cross‐polarization magic angle spinning (CP/MAS) NMR spectra of three natural melanin solids: Sepia officinalis melanin, Sepia officinalis melanin free acid (MFA) and Human hair melanin. The functional group characterization of Human hair melanin by NMR is the first to date and the 13C CP/MAS NMR spectra reported here show improved resolution of chemically inequivalent sites. The observed spectral regions of the solid melanin samples can be assigned to the postulated structural unit of the polymer chain of Sepia MFA derived from solution‐state NMR studies. To assist in the assignment of functional groups in the spectra, the solid‐state CP/MAS NMR spectra are compared with high‐resolution 13C and 15N CP/MAS spectra of four model compounds, L‐dopa, dopamine, 2‐methoxycarbonyl‐3‐ethoxycarbonyl‐4‐methylpyrrole and ethyl 5,6‐dimethoxyindole‐2‐carboxylate. To aid further in the assignment of protonated and non‐protonated carbon atoms, CP contact time dependence and non‐quaternary carbon suppression (NQS) experiments were performed on the melanin samples. The 15N CP/MAS spectra of the melanin samples confirm the presence of indole and pyrrole units in the melanin polymer chain. The NMR peaks observed in all of the melanin samples are relatively broad, presumably owing to the presence of free radicals. Electron spin resonance (ESR) data shows that all three melanin samples contain localized free radicals (g = 2.007), with the Sepia melanin containing a 10‐fold higher free radical density than Human hair melanin. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis and 1H and 13C NMR structural analysis of cis‐ and trans‐2‐imino‐1,3‐ and ‐3,1‐perhydrobenzoxazines and their 3‐ and 1‐N‐methyl derivatives
Authors: Pihlaja Kalevi , Sinkkonen Jari , Fülöp Ferenc
Published: May 2003

cis‐ and trans‐2‐imino‐1,3‐ and ‐3,1‐perhydrobenzoxazines and the N‐methyl derivatives of the latter were synthesized from the corresponding cyclic 1,3‐amino alcohol with cyanogen bromide. The configurations of the studied compounds were confirmed by 1H and 13C NMR spectra. All trans‐fused compounds exist in biased chair–chair conformations as expected, whereas the cis‐fused 1,3‐benzoxazines attain exclusively the O‐in conformations. The cis‐fused 3,1‐benzoxazines, especially the 1‐methyl‐substituted derivatives, tend to favor the N‐out form, obviously owing to the favorable axial orientation of this N‐methyl. Copyright © 2003 John Wiley & Sons, Ltd.
A fast method for the measurement of diffusion coefficients: one‐dimensional DOSY
Authors: Thrippleton Michael J. , Loening Nikolaus M. , Keeler James
Published: May 2003

A new experiment for the single‐scan measurement of diffusion coefficients is presented. The principle is to introduce a spatial variation in the parameters of a conventional pulse sequence, so that all of the scans required to determine some physical parameter can be recorded simultaneously from different parts of the sample. The spectrum is acquired in the presence of a weak read gradient so that the resulting lineshapes contain the information required. The pulse sequence is described in detail and demonstrated on a sample containing three components; its advantages and limitations are discussed in relation to those of existing techniques. For uncrowded spectra with high signal‐to‐noise ratio, this experiment provides an order of magnitude reduction in experiment time compared with conventional methods and is likely to be of most benefit where samples are changing rapidly with time or where a long period of polarization, which may be difficult to reproduce accurately, prohibits the use of multiple‐scan techniques. Copyright © 2003 John Wiley & Sons, Ltd.
Critical investigation of coupled liquid chromatography–NMR spectroscopy in pharmaceutical impurity identification
Authors: Sharman Gary J. , Jones Ian C.
Published: May 2003

In this paper, we investigate the application of coupled LC–NMR to the identification of low‐level impurities. We consider the absolute sensitivity of the technique with our instrumentation, and how this is degraded by peak broadening on and after column, and we compare the sensitivity and other aspects of LC–NMR with a more classical approach of impurity isolation and tube NMR. We show that despite the undoubted advantages of LC–NMR in many situations, for the identification of very low‐level impurities it may not always be the most efficient overall approach when all factors are considered. Copyright © 2003 John Wiley & Sons, Ltd.
Phenylselenenylalkanes, their adducts with the dirhodium complex Rh2(MTPA)4 and ligand exchange mechanisms in solution as studied by 1H, 13C and 77Se NMR spectroscopy
Authors: Malik Shahid , Moeller Stefan , Tóth Gábor , Gáti Tamás , Choudhary Muhammad Iqbal , Duddeck Helmut
Published: May 2003

Twelve secondary phenylselenenylalkanes and ‐cycloalkanes were studied by 1H, 13C and 77Se NMR spectroscopy in the presence of the chiral dirhodium complex Rh2[(R)‐MTPA]4 [Rh–Rh; MTPA‐H = (R)‐(+)‐methoxytrifluoromethylphenylacetic acid, Mosher's acid]. The 1 : 1 and 2 : 1 adducts were identified in solution at low temperatures. Two different mechanisms of ligand exchange, ‘switch’ and ‘replacement,’ were characterized and their energy barriers estimated and steric congestion during the exchange transitions is discussed. Coordination‐induced shifts Δδ(77Se) are generally negative (shielding). For menthone bis(phenylselenoacetal) (7), these values indicate that a selection of the two selenium atoms occurs showing that 7 prefers complexation at the equatorial selenium atom whereas the axial selenium atom is hardly involved. Copyright © 2003 John Wiley & Sons, Ltd.