bluuebunny/crossref_metadata_2025 huggingface dataset:
Escherichia colias an Experimental Organism
Authors: Cronan John E
Published: July 2014

Escherichia coli, a gram‐negative gamma proteobacterium, is presently the best‐understood organism. It is a paradigm organism in bacterial physiology and genetics as well as a key tool in molecular genetics in that many genetic manipulations throughout biology involveE. coli. Molecular cloning into one of manyE. colivector plasmids is a standard procedure in most molecular biology and biotechnology laboratories.E. coliis also the workhorse of recombinant protein production since conditions have been found that allow proteins from across biology to be efficiently expressed in and purified fromE. coli. Indeed, the bulk of x‐ray crystal structures are performed on proteins that were produced in this bacterium. Finally, a collection of mutantE. colistrains each deleted for a gene nonessential for growth in a rich medium provides a resource to test the functions of genes from other organisms by assaying their ability to replace the function of anE. coligene.

Key Concepts:

E. coliis a preferred host for gene cloning due to the high efficiency of introduction of DNA molecules into cells.

E. coliis a preferred host for protein production due to its rapid growth and the ability to express proteins at very high levels.

Bacterial conjugation can be used to transfer large DNA fragments from one bacterium to another.

E. coliis a preferred host for the study of phage biology due to the detailed knowledge of its nucleic acid and protein biosynthetic pathways.

The ability ofE. colito grow on chemically defined media coupled with its extensive genetic toolbox make it a key system in study of bacterial metabolic pathways.
Multivariate Techniques in Ecology
Authors: Reyment Richard A
Published: July 2014

Multivariate analysis (MA) is concerned with the simultaneous examination of two or more variables (in the case of full space) or parts (in the case of simplex space) by means of procedures based on the application of standard methods of linear algebra and differential geometry. The methods are largely universally applicable. In the life sciences, MA is of wide use in animal and plant taxonomy, quantitative genetics, environmetrics, ecology and aspects of evolutionary biology.
Mutualistic Symbioses
Authors: Saffo Mary Beth
Published: July 2014

Mutualistic symbioses are defined as intimate inter‐species interactions beneficial to all species partners. In reality, however, mutualistic symbioses are more intricate, complex, diverse and variable than the formal definition suggests; understanding this complexity is essential to understanding mutualism dynamics. Widely distributed both geographically and taxonomically, mutualistic symbioses play a significant role in the biology of organisms. Iconic examples of mutualisms such as lichens, reef‐building corals with algal symbionts, and mycorrhizal fungi with terrestrial plants, highlight the prevalence of many symbiotic mutualisms in resource‐limited conditions. The several important examples of hereditary microbial symbiosis in insects call attention to the importance of hereditarily transmitted symbioses as well. But there are also mutualisms that do not fit the ecological paradigm of partnerships forged by nutrient scarcity, and evolutionarily persistent, horizontally‐transmitted mutualisms which challenge the notion that hereditary symbiosis is the only stable form of mutualistic symbiosis. In the face of ubiquitous immune defences among organisms, the persistence and ubiquity of mutualistic symbiosis seems a physiologically improbable phenomenon. But recent research suggests a possible resolution to this paradox, in revealing the involvement of immune mechanisms in selection, tolerance and maintenance of beneficial foreign microbes, as well as recognition and elimination of pathogens.

Key Concepts:

Given the ubiquity and effectiveness of immune defences among plants and animals, the existence of chronic, beneficial infections seems a physiologically improbable situation.

Despite its improbability, mutualistic symbiosis is widespread in the biosphere, playing key roles in the evolution and ecology of land plants, tropical and deep‐sea marine ecosystems, the biology of herbivorous animals, and more.

Mutualistic symbioses are diverse, embracing a physiologically, taxonomically, and ecologically diverse array of interactions.

Mutualistic symbioses can incorporate antagonistic as well as mutualistic elements; many can also vary in their biological effects, depending on environmental conditions.

While the metabolic foundation of many mutualistic host‐symbiont interactions lies in symbiotic‐enhanced nutrient exchanges in nutrient‐limited conditions, benefits of symbiotic mutualisms can also include nonnutritional factors such as bioluminescence, drought resistance and enhanced defences against predators and pathogens.

Hereditarily‐transmitted symbioses are often considered the 'ultimate' mutualisms because of the extreme interdependence and striking coevolution of hosts and endosymbionts in such interactions.

However, nonhereditary (horizontally transmitted) mutualisms also can be strongly interdependent, evolutionarily persistent associations, with major impact on the ecology and evolution of plants and animals.
Cold Spring Harbor Laboratory
Authors: Witkowski Jan A
Published: July 2014

The Biological Laboratory was established at Cold Spring Harbor, New York, USA, in 1890 as a summer school for teachers of biology. It began a transition to becoming a research institute in 1898, and in 1904, the Carnegie Institution of Washington created the Station for Experimental Evolution. A third institute, the Eugenics Records Office (ERO), was established in 1910. The ERO was closed in 1940 and the two remaining institutes amalgamated to create the Cold Spring Harbor Laboratory of Quantitative Biology in 1963. Genetics was and remains the central theme of the Laboratory's research, focusing on cancer, but current areas of research also include quantitative biology, neurobiology and plant genetics. The Laboratory is also the leading centre for meetings and courses in experimental biology; over 8500 scientists attend over 50 meetings and 25 courses held annually. The Laboratory's DNA Learning Center provides education in molecular genetics for high school students, whereas the Watson School of Biological Sciences, founded in 1998, grants the PhD degree.

Key Concepts:

Cold Spring Harbor Laboratory is located in Nassau County on Long Island, New York, USA. It is a world‐renowned institute for research on topics of biological and biomedical importance.

The laboratory plays a key role in professional education through its meetings, courses and book publishing.

The Watson School of Biological Science offers graduate training leading to the PhD degree.

The DNA Learning Center provides teaching in molecular genetics for high school students.
Glycosidases: Functions, Families and Folds
Authors: Kötzler Miriam P , Hancock Susan M , Withers Stephen G
Published: July 2014

Glycosidases catalyse the hydrolysis of glycosidic linkages, thereby degrading oligosaccharides and glycoconjugates, the structurally most diverse class of biopolymers. These efficient and highly specific catalysts play important roles in biological processes thus a detailed knowledge of glycosidase function is invaluable for understanding and controlling diseases and for industrial applications. The classification of this huge class of enzymes into families on the basis of amino acid sequence has provided a highly valuable tool for the analysis of structure–function relationships. Furthermore, the steady increase in three‐dimensional structural information is revealing further evolutionary relationships between glycosidase families. In addition to the majority of glycosidases that act via the classical Koshland mechanisms, a growing number of such enzymes that use unusual mechanisms are being uncovered. This confluence of bioinformatics, structural and mechanistic studies has greatly advanced glycosidase engineering and the development of specific glycosidase inhibitors.

Key Concepts:

Classification of glycosidases by sequence similarity in a comprehensive database CAZy has proven to be an invaluable tool to analyse their structures and functions.

Glycosidases adopt a variety of folds.

The vast majority of glycosidases act via Koshland mechanisms with either retention or inversion of the anomeric configuration.

Some glycosidases use unusual mechanisms employing hydration, elimination and/or redox steps.

Detailed mechanistic understanding of glycosidase mechanism has allowed the engineering of glycosynthases and the development of specific inhibitors.
Copy Number Variations and Neuropsychiatric Diseases
Authors: Alliey‐Rodriguez Ney , Gershon Elliot S
Published: July 2014

Copy number variants (CNVs) are submicroscopic deletions and duplications of
deoxyribonucleic acid (DNA)
segments, which can have a high impact on gene expression. Methods to explore CNVs include array comparative genomic hybridisation, single‐nucleotide polymorphism microarrays and whole genome sequencing. Rare CNVs are strongly associated with neuropsychiatric diseases including autism spectrum disorder, schizophrenia, bipolar disorder and disruptions to some specific loci have been related to more than one disorder. The chromosome 22q11.21 deletion is so far the locus identified with the highest risk, 82% for any psychiatric disorder.
De novo
copy number events, those present in cases but not in their parents, also have a significant risk for any of these disorders, with an overall risk of 13% to develop a neuropsychiatric disorder if present anywhere in the genome.

Key Concepts:

Copy number variants are so far the most potent sources of genetic risk for neuropsychiatric disease.

Rare and
de novo
events are associated with neuropsychiatric disorders.
Plant Mineral Nutrition
Authors: Miller Anthony J
Published: July 2014

Several inorganic minerals are essential for plant growth and these are usually obtained by roots from the soil. Availability of minerals in the soil is determined by the physical and chemical characteristics of the soil. Plants can directly influence nutrient availability around the root surface; this zone is called the rhizosphere. Plants adjust root architecture and exudation according to their nutrient requirements and under deficiency these changes can be a marker for nutrient status. Nutrients are taken up from the soil using plasma‐membrane located transporter proteins and excess is stored in the cell vacuole or converted into polymerised storage forms. For crops it is essential to match nutrient supply to demand throughout the growth season to obtain the maximum yield. These nutrient storage forms can be used as agricultural indicators of crop nutrient status and the potential for fertilizer leaching losses. Membrane transporters provide a gateway for nutrient entry into plants, but the selectivity of these filters can breakdown when chemically similar minerals are present at very high concentrations. The minerals may not be essential for growth, but they can enter plant cells and cause toxicity.

Key Concepts:

Several mineral elements are essential for plant growth.

These nutrients are usually obtained from the soil and their availability depends on the physical and chemical properties of the soil.

Plants adjust their root growth according to their nutrient requirements and these changes can be a marker for nutrient status.

It is necessary to matching nutrient supply to demand throughout the growth season to obtain maximum crop yield.

Excess nutrients can be stored in the plant and these storage pools can be used as indicators of nutrient status.

Root plasma membrane located transporters are the gateway for entry of nutrients into the plant and their selectivity is important for determining the toxicity of some elements.
Determinism and Total Explanation in the Biological and Behavioral Sciences
Authors: Winther Rasmus Grønfeldt
Published: July 2014

Should we think of our universe as law‐governed and ‘clockwork’‐like or as disorderly and ‘soup’‐like? Alternatively, should we consciously and intentionally synthesise these two extreme pictures? More concretely, how deterministic are the postulated causes and how rigid are the modelled properties of the best statistical methodologies used in the biological and behavioural sciences? The charge of this entry is to explore thinking about causation in the temporal evolution of biological and behavioural systems. Regression analysis and path analysis are simply explicated with reference to a thought experiment of painting three universes (clockwork, soup and conscious) useful for imagining our actual universe. Attention to historical, structural and mechanistic explanatory perspectives broadens the palette of methodologies available for analysing determinism in, and explanation of, biological and behavioural systems. Each justified methodology provides a partial perspective on complex reality. Is a total explanation of any system ever possible and what would it require?

Key Concepts:

A thought experiment delineating three universes – clockwork, soup, and conscious – assists in understanding statistical methodologies.

Neither extreme rigid determinism nor radical chancy indeterminism permit accurate depictions of a ‘Laplacian chance’, conscious universe.

Standard statistical methodologies related to the General Linear Model (GLM), such as regression analysis and path analysis, synthesise determinism and indeterminism in important ways (e.g. via error terms).

History of science illustrates the plurality of scientific methods.

Inferring causes using statistical analysis is not impossible.

Indeed, randomised experiments and rigorous statistical methodologies can licence causal claims.

An analogy from the physical sciences, displacement of springs, provides a running example for the variety of questions asked of system behaviour from statistical, historical, structural, and mechanistic perspectives.

Historical explanation and mechanistic explanation remain autonomous explanatory perspectives interested, respectively, in the origin and part‐whole structure of a biological or behavioural system.

The general methodological analyses here presented should be complemented with more concrete case studies of, for example, sexuality, intelligence, autism, and ‘criminality’.

Are explanations from distinct explanatory perspectives ‘miscible’ or do we reach an ‘impasse when we attempt to integrate and mix them?
Genetic Profiling in Disaster Victim Identification
Authors: Montelius Kerstin , Stenersen Marguerethe , Sajantila Antti
Published: July 2014

About 30 years ago, Professor Sir Alec Jeffreys described the first
deoxyribonucleic acid (DNA)
‐profiling technique, and genetic profiling was soon implemented for immigration cases, paternity investigations and crime casework. Today, the methods have evolved from the original ‘DNA fingerprints’, to ‘DNA profiling’, which have been adopted as a standard procedure for human identification. New technological innovations, such as next‐generation sequencing, continue to improve the methods to be more efficient, such as throughput. In the disaster victim identification (DVI) context, DNA profiling is one of the primary tools in the aftermath of massive catastrophes and an important part in the process in repatriation of victims to their relatives. The first time DNA profiling was effectively used in a DVI process, was in 1990 in the identification of the victims of the fire on the Norwegian ferry ‘Scandinavian Star’. Since then, DNA profiling has been a mainstay in DVI work, and in some situations the method has proven to be the only doable method for victim identification.

Key Concepts:

Genetic profiling is a primary tool for identification of disaster victims.

A common ante‐mortem (AM) sample is often samples collected from a close relative(s) of the missing person.

Postmortem (PM) samples are appropriate tissue samples collected from the dead body or body part.

Potential contamination should be minimised during all processes.

AM samples and PM samples are analysed with the same genetic markers.

STR markers are at present the most widely used markers for genetic profiling for DVI.

A Bayesian approach regarding statistics (use of prior odds combined with genetic data) when evaluating associations between AM and PM genetic data, allows for an assessment of the strength of the alleged relationship in the identification process.
Genetics of Age at Menarche
Authors: He Chunyan
Published: July 2014

Age at menarche, defined as the age at first menstruation, is a complex trait influenced by both environmental and genetic factors. A younger age at menarche has been linked to increased risks later in life for a number of diseases including reproductive cancers, cardiovascular and metabolic disorders and osteoporosis. A better understanding of the genetic factors influencing menarche may not only help us to gain more mechanistic insight into normal reproduction functions and those associated diseases, but may also have important clinical implications for the identification of high‐risk subgroups that may benefit from early intervention. Our current knowledge of the genetic basis of age at menarche mainly comes from the results from linkage analysis, and candidate gene and genome‐wide association studies. New technologies and approaches, such as next‐generation sequencing and integrative molecular epidemiology, may provide useful tools for the further discovery of the genetic factors impacting age at menarche.

Key Concepts:

Age at menarche varies substantially between individuals. A younger age at menarche has been linked to increased risks for cancer, cardiovascular, and metabolic disorders.

Age at menarche is a complex trait that is influenced by both environmental and genetic factors. It is estimated that approximately 50% of the observed variation in age at menarche is contributed by genetic factors.

Different genetic approaches have identified genetic loci that are responsible for age at menarche. However, the confirmed genetic loci can only explain a small proportion of the observed variation.

Future studies of the genetics of age at menarche will focus on rare genetic variations, gene–environment interactions and functional characterisation of the identified genetic variations.

Identification of the genetic factors impacting age at menarche may help us to understand normal reproduction functions and diseases associated with menarche timing. This information may then be translated into clinical applications that might allow us to predict early menarche and to identify high‐risk subgroups that might benefit from early interventions.
Genetics of

PTEN

Hamartoma Tumour Syndrome
Authors: Pilarski Robert T
Published: July 2014

The
PTEN
hamartoma tumour syndrome (PHTS) represents a group of clinically related syndromes caused by germline mutations in the
PTEN
gene. These include Cowden syndrome (CS), Bannayan–Riley–Ruvalcaba syndrome, adult Lhermitte–Duclos disease and autism spectrum disorders with macrocephaly.
PTEN
mutations lead to increased cancer risks (including breast, thyroid, uterine, renal cell and colon cancers) and benign overgrowth of multiple tissues, presenting in part as dermatologic lesions, gastrointestinal polyps, thyroid structural lesions, lipomas and vascular lesions. Historically, data on the clinical features of PHTS have been based primarily on collected case reports from the literature. More recently, findings from several large United States and European cohorts have added greatly to our understanding of PHTS. The bulk of these data are on patients with CS, the most common of the PHTS component syndromes. Testing and management criteria and recently revised clinical diagnostic criteria have been established for PHTS.

Key Concepts:

PHTS is an important group of clinical disorders, including Cowden syndrome and Bannayan–Riley–Ruvalcaba syndrome, which are defined by presence of a mutation in the
PTEN
gene.

These conditions are of relevance to many clinical specialties because of significantly increased risks for benign and malignant tissue overgrowth.

The data that are available on risks for malignancy and other features of the syndrome have been almost entirely obtained on cohorts of patients who presented to medical attention and were tested because they demonstrated a significant number of PHTS features. This inherently should lead to overestimates of the prevalence of these features.

Projected lifetime cancer risks in recent studies have been approximately 77–85% for breast cancer (women only), 20–38% for thyroid cancer, 20–30% for uterine cancer, 15–34% for renal cell carcinoma and 9–16% for colon cancer.

Common nonmalignant features include gastrointestinal polyps, macrocephaly, specific skin lesions and structural thyroid lesions. Less common features include Lhermitte–Duclos disease, autism spectrum disorder, mental retardation/developmental delay, testicular lipomatosis and vascular anomalies.

Criteria for making a clinical diagnosis of this syndrome have been recently updated to reflect current literature.

The US National Comprehensive Cancer Network has developed testing criteria and medical management criteria which are updated annually.
One‐Step Fabrication of Nanocomposite Thin Films of PTFE in SiOx for Repelling Water
Authors: Zuber Kamil , Murphy Peter , Evans Drew
Published: July 2014

Two major areas of research over the past decades are thin films and nanocomposite materials. By no means are nanocomposite thin films a new concept, but due to improvements in deposition techniques, their use and production has become more popular. In this vein, the paper herein describes the fabrication of nanocomposite films of PTFE in a glass‐like material by introducing PTFE micropowder and siloxane monomer into an atmospheric microwave plasma. Direct analysis of the thin film illustrates that the nanocomposite consists of dispersed PTFE particles in a glass‐like matrix, with no observed chemical bonding between the two phases. Such nanocomposite films, and their fast one step deposition process, are easily applied to a range of substrates, both solid and liquid. At low PTFE content a hydrophobic film is fabricated that is robust to abrasive damage, optically transparent, and possesses excellent dynamic water repelling ability. Increasing the PTFE loading transforms the nanocomposite film into a superhydrophobic material. The practical application of such coatings as repellent optical surfaces in dynamic wetting scenarios is demonstrated.
Experimental validation of a flexible modeling approach for distillation columns with packings
Authors: Ehlers Christoph , Fieg Georg
Published: July 2014

The two main concepts for the modeling of distillation columns are the equilibrium‐stage (EQ) and the nonequilibrium‐stage (NEQ). A model is presented which combines decisive features of both conventional concepts. Based on the idea of a reduced nonequilibrium‐stage (RNEQ), this model can be used for the simulation of distillation columns with packings. In contrast to the conventional NEQ approach, this model neglects the influence of liquid side mass‐transfer coefficients, which ultimately allows to come up with only one empirical equation describing the overall mass transfer. Thus, a considerable reduction in model complexity is reached, which allows for an efficient consideration of new experimental distillation results. Fitted to experimental data, the model is able to predict, how different pressures and chemical systems might affect the separation efficiency. By comparing calculation results with experimentally determined separation efficiencies for three different packing types, these valuable RNEQ qualities are illustrated. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3833–3847, 2014
Spread of X inactivation on chromosome 15 is associated with a more severe phenotype in a girl with an unbalanced t(X; 15) translocation
Authors: Yeung KS , Chee YY , Luk HM , Kan Anita SY , Tang Mary HY , Lau Elizabeth T , Shuen Andrew Y , Lo Ivan FM , Chan Kelvin YK , Chung Brian HY
Published: July 2014

We report on a baby girl with multiple congenital abnormalities, including cleft palate, intrauterine growth restriction, and double outlet right ventricle (DORV) with ventricular septal defect. She had an unbalanced chromosome translocation t (X;15) resulting in monosomy 15pter → p10 and trisomy Xq13.1 → q28. All three copies of Xq encompass the XIST gene. It is known that X chromosome inactivation could spread to the autosome part of an unbalanced translocation involving chromosome X and an autosome. To confirm the spread of X chromosome inactivation on chromosome 15, we evaluate the methylation change by the HumanMethylation450 BeadChip, a whole genome DNA methylation micorarray that includes 15,259 probes spanning 717 genes on chromosome 15. Results showed there was gain in DNA methylation of more than 20% in 586 CpG sites spanning the long arm of chromosome 15. We further examined the hypermethylated CpG sites located in CpG‐island promoter, because genes subjected to X chromosome inactivation will have an increase in DNA methylation level in this region. A total of 75 sites representing 24 genes were hypermethylated. Nearly all of these probes are located in region proximal to the breakpoint, from 15q11.2 to 15q21.3 (35Mb) suggesting that X inactivation was spread to the proximal region of 15q. Gain of DNA methylation, especially in the CpG‐island promoter, can result in functional inactivation of genes, and therefore could potentially worsen the phenotype of our patient. © 2014 Wiley Periodicals, Inc.
Acoustical and Anatomical Determination of Sound Production and Transmission in West Indian (Trichechus manatus) and Amazonian (T. inunguis) Manatees
Authors: Landrau‐giovannetti Nelmarie , Mignucci‐giannoni Antonio A. , Reidenberg Joy S.
Published: July 2014

West Indian (Trichechus manatus) and Amazonian (T. inunguis) manatees are vocal mammals, with most sounds produced for communication between mothers and calves. While their hearing and vocalizations have been well studied, the actual mechanism of sound production is unknown. Acoustical recordings and anatomical examination were used to determine the source of sound generation. Recordings were performed on live captive manatees from Puerto Rico, Cuba and Colombia (T. manatus) and from Peru (T. inunguis) to determine focal points of sound production. The manatees were recorded using two directional hydrophones placed on the throat and nasal region and an Edirol‐R44 digital recorder. The average sound intensity level was analyzed to evaluate the sound source with a T test: paired two sample for means. Anatomical examinations were conducted on six T. manatus carcasses from Florida and Puerto Rico. During necropsies, the larynx, trachea, and nasal areas were dissected, with particular focus on identifying musculature and soft tissues capable of vibrating or constricting the airway. From the recordings we found that the acoustical intensity was significant (P < 0.0001) for both the individuals and the pooled manatees in the ventral throat region compared to the nasal region. From the dissection we found two raised areas of tissue in the lateral walls of the manatee's laryngeal lumen that are consistent with mammalian vocal folds. They oppose each other and may be able to regulate airflow between them when they are adducted or abducted by muscular control of arytenoid cartilages. Acoustic and anatomical evidence taken together suggest vocal folds as the mechanism for sound production in manatees. Anat Rec, 297:1896–1907, 2014. © 2014 Wiley Periodicals, Inc.
ORIGINS AND ACTIVATION OF PROPHENOLOXIDASES IN THE DIGESTIVE TRACT OF THE CRICKET, Gryllus bimaculatus
Authors: Joseph Woodring
Published: July 2014

The function of Phenoloxidases (POs) in sclerotization and defense in insects is well understood, but little is known concerning their occurrence, origins, and function in the digestive tract. In Gyrllus bimaculatus gut all of the PO activity is found in the lumen of the digestive tract, and no detectible activity is found in homogenates of the gut epithelium or secretions from incubated epithelial tissues. Prophenoloxidases (PPOs) are synthesized in the hemocytes of  Bombyx mori and are transported into the cuticle. It is suggested that the PPOs in the caecal lumen of G. bimaculatus likewise are synthesized in hemocytes and are transported by unknown means into the caecal lumen, where they are activated to POs by trypsin. Peristalsis transports the POs both forward into the crop and posterior within the peritrophic membrane into the hind gut. The PPOs in the hemolymph consist of a trimer (270–280 kDa) and a tetramer (340–370 kDa). The active POs in the gut lumen consist of a monomer (85–95 kDa) in addition to an activated trimer and tetramer.
Novel Coronene–Naphthalene Dimide‐Based Donor–Acceptor Pair for Tunable Charge‐Transfer Nanostructures
Authors: Kumar Mohit , George Subi J.
Published: July 2014

Charge‐transfer (CT) assemblies of aromatic donor (D) and acceptor (A) molecules have recently gained attention as a promising material for organic electronics and ferroelectrics. Two major factors which govern their functions are the strength of CT interaction and their supramolecular nanostructuring. Here we present coronene‐naphthalenediimide (NDI)‐based novel D‐A pairs that form alternately stacked CT assemblies. Through systematic substitution of the NDI derivatives and studying their CT interactions with coronene, a clear understanding of the secondary forces responsible for controlling their association is gained. Finally, the use of CT‐based supramolecular amphiphiles for their nanostructural engineering into ordered one‐dimensional (1‐D) assemblies is demonstrated.
Acid–Base‐Responsive Intense Charge‐Transfer Emission in Donor–Acceptor‐Conjugated Fluorophores
Authors: Inouchi Toshifumi , Nakashima Takuya , Kawai Tsuyoshi
Published: July 2014

Herein we report on the synthesis and acid‐responsive emission properties of donor–acceptor (D–A) molecules that contain a thienothiophene unit. 2‐Arylthieno[3,2‐b]thiophenes were conjugated with an N‐methylbenzimidazole unit to form acid‐responsive D–A‐type fluorophores. The D–A‐conjugated fluorophores showed intense intramolecular charge‐transfer (ICT) emission in response to acid. The effect of the substitution on their photophysical properties as well as their solvent‐dependence indicated non‐twisting ICT emission in protonated D–A molecules. The quinoidal character of 2‐arylthienothiophene as a donor part is discussed, as it is assumed that it contributes to suppression of the molecular twisting in the excited state, therefore decreasing the nonradiative rate constant, thereby resulting in the intense ICT emission. Acid–base‐sensitive triple‐color emission was also achieved by the introduction of a base‐responsive phenol group in the donor part.
Anal acoustic reflectometry predicts the outcome of percutaneous nerve evaluation for faecal incontinence
Authors: Hornung B R , Carlson G L , Mitchell P J , Klarskov N , Lose G , Telford K J , Kiff E S
Published: July 2014

Background

Sacral nerve stimulation (SNS) is effective for some patients with faecal incontinence. Before insertion of a costly implant, percutaneous nerve evaluation (PNE) is undertaken to identify patients likely to report success from SNS. The aim of this study was to determine whether variables of anal sphincter function measured by anal acoustic reflectometry (AAR) could predict the outcome of PNE for faecal incontinence.

Methods

Women with faecal incontinence undergoing PNE were recruited. AAR, followed by anal manometry, was performed on the day of surgery, immediately before PNE. The outcome of PNE was determined by bowel diary results and incontinence severity score. Patients with a successful PNE outcome were compared with those with an unsuccessful outcome; logistic regression analysis was used to identify any independent predictors of success.

Results

Fifty-two patients were recruited, of whom 32 (62 per cent) had a successful PNE outcome and 20 (38 per cent) an unsuccessful outcome. The AAR variable opening pressure was significantly greater in patients who subsequently had a successful PNE result compared with the pressure in patients who did not (28 versus 17 cmH2O; P = 0·008). No difference was seen in the manometric equivalent, maximum resting pressure. Opening pressure was an independent predictor of success with an odds ratio of 1·08 (95 per cent confidence interval 1·01 to 1·16; P = 0·018).

Conclusion

AAR is a sensitive test of sphincter function and can identify differences between patients who respond to PNE and those who do not. Opening pressure is an independent predictor of success in PNE, and may be of value in the selection of patients for this expensive treatment option.
Chain Length Effect of the Multidentate Block Copolymer Strategy to Stabilize Ultrasmall Fe3O4 Nanoparticles
Authors: Chan Nicky , Li Puzhen , Oh Jung Kwon
Published: July 2014

A multidentate block copolymer (MDBC) strategy to stabilize ultrasmall superparamagnetic iron oxide nanoparticles (USNPs) as biocompatible T1‐positive contrast agents for magnetic resonance imaging (MRI) is explored. The MDBC is designed with a poly(methacrylic acid) (PMAA) block having pendant carboxylates as multidentate anchoring groups and a hydrophilic polymethacrylate block having pendant oligo(ethylene oxide) chains (POEOMA). A series of multifunctional MDBCs with different chain lengths of POEOMA and PMAA blocks were synthesized by atom transfer radical polymerization and subsequent hydrolytic cleavage. The resultant aqueous MDBC/USNP colloids fabricated through a ligand‐exchange process were characterized to investigate the effect of chain lengths of POEOMA‐b‐PMAA copolymers on size, morphology, and colloidal stability as well as relaxometric properties and in vitro MRI performance. The results suggest that the optimal design of chain lengths of both anchoring and hydrophilic blocks is required for enhanced colloidal stability under biologically relevant conditions as well as effective T1‐weighted contrast enhancement.
Design and Characterization of Two Bifunctional Cryptophane A‐Based Host Molecules for Xenon Magnetic Resonance Imaging Applications
Authors: Rossella Federica , Rose Honor May , Witte Christopher , Jayapaul Jabadurai , Schröder Leif
Published: July 2014

Cryptophanes have been shown to be a promising tool in xenon magnetic resonance imaging (MRI) applications. The affinity of xenon for molecular host structures such as cryptophane‐A (CrA) and the large xenon chemical shift that can be detected in the presence of such hosts has motivated the synthesis of a number of cryptophane‐based MRI biosensors. Bifunctional biosensors that incorporate both a fluorophore and a cryptophane moiety are flexible tools for evaluating the intracellular localization and quantifying cellular uptake/binding of such xenon hosts in conjunction with testing their MRI capabilities. In this study, we compare the performance of a new compound that bears tetramethylrhodamine (TAMRA), CrA‐PEG‐TAMRA (PEG=polyethylene glycol), with our previously synthesized compound in which fluorescein (FAM) was the optical reporter. We demonstrate that these biosensors are suitable candidates for MRI‐based cell‐tracking studies; specifically, the new addition of a rhodamine derivative will allow for multiplexing experiments and showed slightly improved NMR spectroscopic behavior. Importantly, both biosensors display equally good cell‐labeling efficiency, which facilitates the acquisition of high‐quality xenon magnetic resonance images in two different cell lines. This study describes a simple synthetic approach for the production of biologically compatible bifunctional compounds. These biosensors can be used as they are for cell labeling but can also serve as building blocks for further functionalization and cryptophane‐based xenon biosensor design with MRI and fluorescence multiplexing options.
Spectroscopic techniques and chemometrics in analysis of blends of extra virgin with refined and mild deodorized olive oils
Authors: Wójcicki Krzysztof , Khmelinskii Igor , Sikorski Marek , Caponio Francesco , Paradiso Vito M. , Summo Carmine , Pasqualone Antonella , Sikorska Ewa
Published: July 2014

The capability of different spectroscopic techniques in estimation of adulteration of extra virgin olive oil with mild deodorized and refined olive oils was investigated. The visible absorption and ultraviolet–visible fluorescence spectra were distinctly different for oils of different quality grades. Differences in the near‐ and mid‐IR absorption spectra were less pronounced and could only be revealed by principal component analysis. The calibration models for estimation of adulterant oil in the blends obtained using partial least squares (PLS) and principal component regression (PCR) showed similar performance using all of the examined spectroscopic techniques. The simultaneous analysis of combined spectra using concatenated matrix did not improve the calibration results. The prediction parameters for the set of 20 samples were: R2>0.96, the relative error of prediction (REP) was in the range 5.6–12.0%. The RPD (ratio of the SD of reference values to RMSEP) were in the range of 5.1–10.9, indicating that all models were at least suitable for quality control.

MIR, NIR, VIS absorption and fluorescence spectra of extra virgin, mild deodorized and refined olive oils were characterized. Multivariate regression analysis of spectra using PCR and PLS methods enabled quantification of adulterant concentration in the blends of extra virgin olive oil with mild deodorized and refined olive oils. The calibration models showed similar performance using all of the examined spectroscopic techniques.
Stripping Analysis of Trace Arsenic Based on the MnOx/AuNPs Composite Film Modified Electrode in Alkaline Media
Authors: Wu Shouguo , Zhao Qiping , Zhou Lei , Zhang Zhixin
Published: July 2014

A simple, rapid fabricated and sensitive modified electrode for detection of As(III) in alkaline media was proposed. The modified electrode was prepared by co‐electrodeposition of manganese oxides (MnOx) and gold nanoparticles (AuNPs) on the glassy carbon electrode (GCE) with cyclic voltammetry. Linear sweep anodic stripping voltammetry (LS‐ASV) was employed for the determination of arsenic (III) without interference from Cu(II), Hg(II), and other coexisting metal ions. A lower detection limit of 0.057 µg L−1 (S/N=3) were obtained with a accumulation time of 200 s. The proposed method was successfully applied to determine arsenic (III) in real water samples with satisfactory recoveries.
Role of Solution‐Processable Polyethylenimine Electrode Interlayer in Fabricating Air‐Stable Polymer Light‐Emitting Diodes
Authors: Lin Ming‐Wei , Lin Yu‐Chun , Rauan Asslbekov , Wen Ten‐Chin , Hsu Yao‐Jane , Guo Tzung‐Fang
Published: July 2014

This work investigates the mechanisms for the enhanced injection of electrons from a solution‐processable polyethyleneimine (PEI) interlayer/aluminum (Al), silver (Ag), or gold (Au) electrodes in phenyl‐substituted poly(para‐phenylene vinylene) (PPV) copolymer (SY‐PPV)‐based polymer light‐emitting diodes (PLEDs). The bilayer cathode significantly enhances electron injection and device performance, and is comparable to that of PLEDs using low work function metals, such as calcium (Ca) or lithium fluoride (LiF)/Al as the cathode. The functions of the PEI interlayer are characterized by current densitylight intensityvoltage (JLV) and photovoltaic measurements, X‐ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. The thin PEI film forms a dipole layer to shift the vacuum level of the electroluminescent polymer and decrease the barrier height for electron injection. The existing dipoles are correlated with a large numbers of amino groups in the PEI polymer. As a result, the PLEDs with PEI/Al, PEI/Ag, and PEI/Au bilayer cathodes exhibit markedly enhanced performances. The application of air‐stable metals as the cathode allows flexibility in the design of device cathode structures for real applications.
Valence Bond‐Based Hybrid Quantum Mechanics Molecular Mechanics Approaches and Proper Inclusion of the Effect of the Surroundings
Authors: Shurki Avital , Sharir‐Ivry Avital
Published: July 2014

The pioneering development of multiscale models for complex chemical systems by Karplus, Levitt, and Warshel, including the hybrid quantum mechanics molecular mechanics (QM/MM) approach and its application to enzymes, established a new field in chemistry that allows the modeling of reactivity within complex chemical systems. Inspired by the potential of such methods, many groups developed different QM/MM variants. Valence bond (VB) theory, which always was and still is an important conceptual tool for chemists, is well suited to deal with problems of chemical reactivity. Hence, here we review VB‐based QM/MM methods, including the early semi‐empirical methods that utilize VB concepts and more recent ab initio VB‐based QM/MM methods. Special emphasis is given to the different ways to include effects of the surroundings on the solute. It is shown that within the VB framework, simple mechanical embedding for each diabatic state, followed by mixing of the states, accounts for most of these effects.
The role of moral commitment within the Investment Model
Authors: Rodrigues David , Lopes Diniz
Published: July 2014

The Investment Model (Rusbult, 1980) defines general commitment as a long‐term orientation towards relationship maintenance and feelings of psychological attachment, influenced by satisfaction, quality of alternatives and intrinsic/extrinsic investments. We suggest the importance of additionally assessing moral commitment, defined by an intrapersonal predisposition to remain in the relationship (Johnson, 1991). We argue moral commitment's association to perceived intrinsic investments acting as internal barriers influencing general commitment and promoting relationship maintenance. A correlational study resorting to structural equation modelling showed that moral commitment predicted intrinsic investments, which in turn predicted general commitment (Model 1). No direct paths emerged from moral commitment to satisfaction or quality of alternatives (Model 2), nor it emerged as a fourth direct predictor of general commitment (Model 3). Results are discussed under relationships maintenance and dissolution frameworks.
A New Utility‐Consistent Econometric Approach to Multivariate Count Data Modeling
Authors: Bhat Chandra R. , Paleti Rajesh , Castro Marisol
Published: July 2014

In the current paper, we propose a new utility‐consistent modeling framework to explicitly link a count data model with an event‐type multinomial‐choice model. The proposed framework uses a multinomial probit kernel for the event‐type choice model and introduces unobserved heterogeneity in both the count and discrete‐choice components. Additionally, this paper establishes important new results regarding the distribution of the maximum of multivariate normally distributed variables, which form the basis to embed the multinomial probit model within a joint modeling system for multivariate count data. The model is applied to analyzing out‐of‐home non‐work episodes pursued by workers, using data from the National Household Travel Survey. Copyright © 2014 John Wiley & Sons, Ltd.
Thermal acclimation and nutritional history affect the oxidation of different classes of exogenous nutrients in Siberian hamsters, Phodopus sungorus
Authors: McCue Marshall D. , Voigt Christian C. , Jefimow Małgorzata , Wojciechowski Michał S.
Published: July 2014

During acclimatization to winter, changes in morphology and physiology combined with changes in diet may affect how animals use the nutrients they ingest. To study (a) how thermal acclimation and (b) nutritional history affect the rates at which Siberian hamsters (Phodopus sungorus) oxidize different classes of dietary nutrients, we conducted two trials in which we fed hamsters one of three 13C‐labeled compounds, that is, glucose, leucine, or palmitic acid. We predicted that under acute cold stress (3 hr at 2°C) hamsters previously acclimated to cold temperatures (10°C) for 3 weeks would have higher resting metabolic rate (RMR) and would oxidize a greater proportion of dietary fatty acids than animals acclimated to 21°C. We also investigated how chronic nutritional stress affects how hamsters use dietary nutrients. To examine this, hamsters were fed four different diets (control, low protein, low lipid, and low‐glycemic index) for 2 weeks. During cold challenges, hamsters previously acclimated to cold exhibited higher thermal conductance and RMR, and also oxidized more exogenous palmitic acid during the postprandial phase than animals acclimated to 21°C. In the nutritional stress trial, hamsters fed the low protein diet oxidized more exogenous glucose, but not more exogenous palmitic acid than the control group. The use of 13C‐labeled metabolic tracers combined with breath testing demonstrated that both thermal and nutritional history results in significant changes in the extent to which animals oxidize dietary nutrients during the postprandial period. J. Exp. Zool. 321A: 503–514, 2014. © 2014 Wiley Periodicals, Inc.
Gender, age‐related, and regional differences of the magnetization transfer ratio of the cortical and subcortical brain gray matter
Authors: Mascalchi Mario , Toschi Nicola , Ginestroni Andrea , Giannelli Marco , Nicolai Emanuele , Aiello Marco , Soricelli Andrea , Diciotti Stefano
Published: July 2014

Purpose

To explore gender, age‐related, and regional differences of magnetization transfer ratio (MTR) of brain cortical and subcortical gray matter (GM).

Materials and Methods

In all, 102 healthy subjects (51 women and 51 men; range 25–84 years) were examined with 3‐mm thick MT images. We assessed MTR in automatically segmented GM structures including frontal, parietal‐insular, temporal, and occipital cortex, caudate, pallidus and putamen, and cerebellar cortex. A general linear model analysis was conducted to ascertain the linear and quadratic relationship among the MTR and gender, age, and anatomical structure.

Results

The effect of gender was borderline (P = 0.07) in all GM structures (with higher MTR values in men), whereas age showed a significant linear as well as quadratic effect in all cortical and subcortical GM structures (P ≤ 0.001). Quadratic age‐related decrease in MTR began at about 40 years of age. Mean and standard deviation (SD) of MTR had the following decreasing order: thalamus (58.3 + 0.8), pallidus (56.8 ± 1.3), caudate (55.5 ± 1.6) and putamen (54.6 ± 1.1); temporal (56.8 ± 0.9), parietal‐insular (56.8 ± 1.1), frontal (56.5 ± 1.1), occipital (55.4 ± 1.0) and cerebellar (53.2 ± 1.0) cortex. In post‐hoc testing, all regional pairwise differences were statistically significant except pallidus vs. temporal or parietal‐insular cortex, caudate vs. occipital cortex, frontal vs. parietal‐insular or temporal cortex.

Conclusion

MTR of the cortical and subcortical brain GM structures decreases quadratically after midlife and shows significant regional differences. J. Magn. Reson. Imaging 2014;40:360–366 © 2013 Wiley Periodicals, Inc.