bluuebunny/crossref_metadata_2025 huggingface dataset:
Fitness: Philosophical Problems
Authors: Ramsey Grant , Pence Charles H
Published: June 2013

Fitness plays many roles throughout evolutionary theory, from a measure of populations in the wild to a central element in abstract theoretical presentations of natural selection. It has thus been the subject of an extensive philosophical literature, which has primarily centred on the way to understand the relationship between fitness values and reproductive outcomes. If fitness is a probabilistic or statistical quantity, how is it to be defined in general theoretical contexts? How can it be measured? Can a single conceptual model for fitness be offered that applies to all biological cases, or must fitness measures be case‐specific? Philosophers have explored these questions over the last several decades, largely in the context of an influential definition of fitness proposed in the late 1970s: the propensity interpretation. This interpretation as first described undeniably suffers from significant difficulties, and debate regarding the tenability of amendments and alternatives to it remains unsettled.

Key Concepts:

Actual offspring production is an unsuitable definition of fitness.

The propensity interpretation of fitness was proposed as a way to base fitness on expected, rather than actual, offspring production.

The propensity interpretation is problematic, as it makes fitness difficult to measure, relies centrally on the arithmetic mean and fails to take into account local environmental factors.

Some philosophers have rejected the propensity interpretation in favour of an ecological fitness concept or a purely statistical fitness concept.

Others have attempted to modify the propensity interpretation in order to resolve its problems.

The debate over which of these concepts of fitness best solves the philosophical problems at hand remains unsettled.
Fixation Probabilities and Times
Authors: Otto Sarah P , Whitlock Michael C
Published: June 2013

The fixation probability of an allele is the probability that it will eventually be the ancestor of all the alleles within a population at that locus. Population genetics theory has demonstrated that the probability of fixation is approximately proportional to the selection coefficient of a weak beneficial mutation, because such mutations are susceptible to stochastic loss while being rare despite their advantage. The time to fixation is the number of generations that it takes for an allele to progress from its initial frequency to fixation. This time is inversely proportional to the selection coefficient of a beneficial allele. Interestingly, though deleterious alleles are much less likely to fix, the time that they take to do so is, on average, the same as for a beneficial allele with the same magnitude of selective effect.

Key Concepts:

The fixation probability of an allele is the probability that it will eventually be the ancestor of all the alleles within a population at that locus.

Even beneficial mutations may not fix within a population.

The fixation probability of a beneficial allele is approximately proportional to its selection coefficient.

Deleterious mutations are unlikely to fix, but they can fix if their selective disadvantage is sufficiently weak and the population size sufficiently small.

The time for a new allele to fix within a population is inversely proportional to the magnitude of selection for both beneficial and deleterious alleles.
Ethylene
Authors: Chang Caren , Schaller G Eric , Resnick Josephine S
Published: June 2013

Ethylene, a simple hydrocarbon gas, is a plant growth regulator that profoundly affects growth and development. Ethylene plays an important role in a wide range of processes, including fruit ripening, abscission, senescence and responses to biotic and abiotic stresses. Plants synthesise ethylene in response to diverse developmental factors and environmental stimuli. Responses to ethylene occur through a conserved ethylene signalling pathway that was first elucidated by molecular genetic dissection in the plant

Arabidopsis thaliana

. The ethylene‐signalling pathway comprises a unique combination of signalling components, beginning with ethylene receptors localised primarily at the endoplasmic reticulum membrane. Ethylene signalling leads to changes in gene expression in the nucleus. Ethylene also exhibits complex interactions with the signalling pathways of a number of other plant signals. An understanding of the regulatory mechanisms involved in ethylene biosynthesis and ethylene signalling has important agricultural and economic implications.

Key Concepts:

Ethylene gas (C
2
H
4
) is a plant growth regulator that has profound effects on growth and development.

Plants synthesise ethylene from the amino acid
l
‐methionine via a simple biosynthetic pathway consisting of three enzymatic steps.

Gene family members encoding the ethylene biosynthesis enzymes are differentially expressed in response to diverse developmental and environmental factors; additionally, ACC synthase isozymes, which catalyse the penultimate step in the pathway, are regulated by protein turnover.

The ethylene signalling pathway, which was genetically dissected in the reference plant
Arabidopsis
, is conserved in plants and involves a unique combination of signalling components.

The ethylene signal is perceived by protein complexes residing at the ER membrane and transduction of the signal activates a transcriptional cascade resulting in rapid changes in gene expression.

Protein turnover plays a critical role in both ethylene biosynthesis and ethylene signalling.

Ethylene displays complex interactions with a variety of other signals to control a wide array of processes.

The ability to control ethylene biology has far‐reaching consequences in agriculture and horticulture.
Molecular Genetics of Achondroplasia
Authors: Narayana Jyoti , Horton William A
Published: June 2013

Affecting approximately 250 000 individuals worldwide, achondroplasia (Ach) represents a family of skeletal dysplasias. Although inherited as an autosomal dominant trait, it results most often from a new mutation to unaffected parents. Virtually all patients have the same mutation in the gene that codes for the receptor tyrosine kinase, FGFR3. The mutation exaggerates the receptor's inhibitory functions on bone growth resulting in characteristic clinical features. Similar mutations of
FGFR3
cause other members of this disease family. Our understanding of how mutant FGFR3 antagonises bone growth remains incomplete, and delineating the relevant molecular details has proved challenging. Nevertheless, new insights into the FGFR3 biology, that is, downstream FGFR3 signals are modulated by the paracrine hormone CNP, FGFR3 is processed to a fragment with potential nuclear function and FGFR3 signal output is influenced by the molecular chaperone Hsp90, have advanced the field and provided a glimpse into future growth stimulating treatments for Ach.

Key Concepts:

Achondroplasia is the prototype of a ‘family’ of human skeletal dysplasias characterised by dwarfism and characteristic craniofacial manifestations.

Achondroplasia results from gain of function mutations of the tyrosine kinase‐mediated receptor, FGFR3, which is an important negative regulator of linear bone growth.

Although achondroplasia can be inherited as an autosomal dominant trait, it most often results from
de‐novo
mutations to nonachondroplastic parents. The new mutations display a paternal age effect. Virtually all patients with achondroplasia have the same
FGFR3
mutation.

Other mutations of
FGFR3
that enhance its function cause similar but more or less severe dwarfing conditions, such as thanatophoric dysplasia and hypochondroplasia.

FGFR3 acts through ‘signals’ it transmits to the cellular machinery that regulates the proliferation and other behaviours of cells responsible for bone growth – chondrocytes that occupy the growth plates of growing bones. The predominant signalling output involves tyrosine kinase cascades collectively referred to as the MAPK signalling pathway. FGFR3 receptors bearing the achondroplasia mutation exhibit exaggerated MAPK signalling when investigated in both cell culture and mouse models of achondroplasia.

The major goal in developing treatments for achondroplasia has been to safely reduce the output of FGFR3 signals to or towards normal. Strategies have ranged from blocking receptor activation to inhibiting FGFR3 tyrosine kinase activity to shortening the survival of actively signalling receptor to antagonising signals downstream of the receptor. These strategies are based on understanding the relevant molecular events. The most promising strategy at present involves administration of the peptide, CNP, which antagonises MAPK signals initiated by FGFR3.
Genetics of Lipodystrophies
Authors: Vigouroux Corinne , Bidault Guillaume , Capeau Jacqueline
Published: June 2013

Human genetic lipodystrophic syndromes are rare conditions with total or partial body fat loss, severe lipid and glucose alterations and insulin resistance, leading to early diabetes, cardiovascular and hepatic complications. Most generalised forms, recessively inherited, result from mutations in four proteins, mainly 1‐acylglycerol‐3‐phosphate‐O‐acyltransferase‐2 (AGPAT2) involved in triglyceride synthesis, or seipin involved in the adipocyte lipid droplet formation/maintenance but also in caveolin‐1 and cavin‐1/polymerase I and transcript release factor, expressed in caveolae and at the lipid droplet surface. Partial lipodystrophic syndromes, generally dominantly inherited, mainly involve A‐type lamins (
LMNA)
, forming the nuclear lamina, or the adipogenic transcription factor peroxisome proliferator‐activated‐receptor‐gamma. Less frequently Akt2, in the insulin signalling pathway, perilipin and cell‐death‐inducing‐DFF45‐like‐effector‐C, controlling adipocyte triglyceride storage, are affected. Insulin resistance and lipodystrophy can also be present in genetic syndromes of premature ageing as the Hutchinson–Gilford progeria or mandibuloacral dysplasia (
LMNA
or
ZMPSTE24
) and the Werner syndrome (affecting the helicase WRN). Patients’ management is difficult and recombinant human leptin treatment could be helpful.

Key Concepts:

Adipose tissue releases a number of factors and hormones and plays an important physiological role, only recently considered.

Genetic lipodystrophic syndromes are a heterogeneous group of diseases with lipoatrophy either generalised or partial.

The very limited fat expansion seen in lipodystrophies results in severe metabolic alterations and early complications as a result of fat overwhelming by nutriments.

Partial lipodystrophies due to a single gene mutation associate both fat hypertrophy and fat atrophy, stressing for the differential physiology of differently located fat depots.

A number of genetic lipodystrophies affect proteins involved in lipid droplet function, which stresses the underrecognised role of lipid droplet in adipocyte physiology.

The transcription factor PPARγ plays important roles in adipogenesis but also at the level of the vascular wall.

Mutations in the gene encoding lamin A/C result in a wide range of diseases collectively called laminopathies.

Human recombinant leptin can improve the metabolic alterations present in lipodystrophic patients with a low leptin level.
PEGylated Micelle Nanoparticles Encapsulating a Non‐Fluorescent Near‐Infrared Organic Dye as a Safe and Highly‐Effective Photothermal Agent for In Vivo Cancer Therapy
Authors: Cheng Liang , He Weiwei , Gong Hua , Wang Chao , Chen Qian , Cheng Zhengping , Liu Zhuang
Published: June 2013

Photothermal therapy (PTT), as a minimally invasive and highly effective cancer treatment approach, has received widespread attention in recent years. Tremendous effort has been devoted to explore various types of photothermal agents with high near‐infrared (NIR) absorbance for PTT cancer treatment. Despite many exciting progresses in the area, effective yet safe photothermal agents with good biocompatibility and biodegradability are still highly desired. In this work, a new organic PTT agent based on polyethylene glycol (PEG) coated micelle nanoparticles encapsulating a heptamethine indocyanine dye IR825 is developed, showing a strong NIR absorption band and a rather low quantum yield, for in vivo photothermal treatment of cancer. It is found that the IR825–PEG nanoparticles show ultra‐high in vivo tumor uptake after intravenous injection, and appear to be an excellent PTT agent for tumor ablation under a low‐power laser irradiation, without rendering any appreciable toxicity to the treated animals. Compared with inorganic nanomaterials and conjugated polymers being explored in PTT, the NIR‐absorbing micelle nanoparticles presented here may have the least safety concern while showing excellent treatment efficacy, and thus may be a new photothermal agent potentially useful in clinical applications.
Toward Strong and Tough Glass and Ceramic Scaffolds for Bone Repair
Authors: Fu Qiang , Saiz Eduardo , Rahaman Mohamed N. , Tomsia Antoni P.
Published: June 2013

The need for implants to repair large bone defects is driving the development of porous synthetic scaffolds with the requisite mechanical strength and toughness in vivo. Recent developments in the use of design principles and novel fabrication technologies are paving the way to create synthetic scaffolds with promising potential for reconstituting bone in load‐bearing sites. Here, the state of the art in the design and fabrication of bioactive glass and ceramic scaffolds that have improved mechanical properties for structural bone repair is reviewed. Scaffolds with anisotropic and periodic structures can be prepared with compressive strengths comparable to human cortical bone (100−150 MPa), while scaffolds with an isotropic structure typically have strengths in the range of trabecular bone (2−12 MPa). However, the mechanical response of bioactive glass and ceramic scaffolds in multiple loading modes such as flexure and torsion—as well as their mechanical reliability, fracture toughness, and fatigue resistance—has received little attention. Inspired by the designs of natural materials such as cortical bone and nacre, glass‐ceramic and inorganic/polymer composite scaffolds created with extrinsic toughening mechanisms are showing potential for both high strength and mechanical reliability. Future research should include improved designs that provide strong scaffolds with microstructures conducive to bone ingrowth, and evaluation of these scaffolds in large animal models for eventual translation into clinical applications.
Understanding the Role of Nanostructures for Efficient Hydrogen Generation on Immobilized Photocatalysts
Authors: Jiang Zhelong , Tang Yuxin , Tay Qiuling , Zhang Yanyan , Malyi Oleksandr I. , Wang Danping , Deng Jiyang , Lai Yuekun , Zhou Huanfu , Chen Xiaodong , Dong Zhili , Chen Zhong
Published: June 2013

For the purpose of efficiently utilizing the renewable solar energy, it is of vital importance to understand the key factors that contribute to the performance merits for photocatalysis applications. In this work, we find that anatase titania nanostructures with high efficiency in photoelectrochemical cell (PEC) do not necessarily retain the same good performance when used in direct heterogeneous reaction (DHR). Investigation is carried out to elucidate how the electronic properties of the different nanostructures are correlated with the PEC and DHR efficiencies. Good PEC cell performance is identified to be related to topotactically formed samples with intimately connected particles that facilitate easy charge transfer. Additional benefit for PEC cell is found to be achieved from the vectorial conduction pathway in the pseudo one dimensional structure. On the other hand, high activity of DHR photocatalysis is attributed mainly to the exposed high reactivity crystal facets. The presence of anatase TiO2 {010} facets is identified to enhance electron‐hole separation and create specific surface states that facilitate interactions across the semiconductor/electrolyte interfaces.
Acquisition of cytogenetic abnormalities in patients with IPSS defined lower‐risk myelodysplastic syndrome is associated with poor prognosis and transformation to acute myelogenous leukemia
Authors: Jabbour Elias , Takahashi Koichi , Wang Xuemei , Cornelison A. Megan , Abruzzo Lynne , Kadia Tapan , Borthakur Gautam , Estrov Zeev , O'Brien Susan , Mallo Mar , Wierda William , Pierce Sherry , Wei Yue , Sole Francisco , Chen Rui , Kantarjian Hagop , Garcia‐Manero Guillermo
Published: June 2013

We hypothesized that the dynamic acquisition of cytogenetic abnormalities (ACA) during the follow up of myelodysplastic syndromes (MDS) could be associated with poor prognosis. We conducted a retrospective analysis of 365 patients with IPSS low or intermediate‐1 risk MDS who had at least two consecutive cytogenetic analyses during the follow up. Acquisition of cytogenetic abnormalities was detected in 107 patients (29%). The most frequent alteration involved chromosome 7 in 21% of ACA cases. Median transformation‐free and overall survival for patients with and without ACA were 13 vs. 52 months (P = 0.01) and 17 vs. 62 months (P = 0.01), respectively. By fitting ACA as a time‐dependent covariate, multivariate Cox regression analysis showed that patients with ACA had increased risk of transformation (HR = 1.40; P = 0.03) or death (HR = 1.45; P = 0.02). Notably, female patients with therapy‐related MDS (t‐MDS) had an increased risk of developing ACA (OR = 5.26; P < 0.0001), although subgroup analysis showed that prognostic impact of ACA was not evident in t‐MDS. In conclusion, ACA occurs in close to one third of patients with IPSS defined lower risk MDS, more common among patients with t‐MDS, but has a significant prognostic impact on de novo MDS. Am. J. Hematol. 88:831–837, 2013. © 2013 Wiley Periodicals, Inc.
Eosinophilia in routine blood samples and the subsequent risk of hematological malignancies and death
Authors: Andersen Christen Lykkegaard , Siersma Volkert Dirk , Hasselbalch Hans Carl , Lindegaard Hanne , Vestergaard Hanne , Felding Peter , de Fine Olivarius Niels , Bjerrum Ole Weis
Published: June 2013

Eosinophilia may represent an early paraclinical sign of hematological malignant disease, but no reports exist on its predictive value for hematological malignancies. From the Copenhagen Primary Care Differential Count (CopDiff) Database, we identified 356,196 individuals with at least one differential cell count (DIFF) encompassing the eosinophil count during 2000–2007. From these, one DIFF was randomly chosen and categorized according to no (<0.5 × 109/L), mild (≥0.5–1.0 × 109/L) or severe (≥1.0 × 109/L) eosinophilia. From the Danish Cancer Registry and the Danish Civil Registration System, we ascertained hematological malignancies and death within 3 years following the DIFF. Using multivariable logistic regression odds ratios (ORs) were calculated and adjusted for previous eosinophilia in a DIFF, sex, age, year, month, C‐reactive protein, previous cancer, and comorbidity. ORs for developing Hodgkin's lymphoma (HL) was significantly increased in individuals exhibiting severe eosinophilia, OR = 9.09 (C.I. 2.77–29.84), P = 0.0003. The association with classical myeloproliferative neoplasms (cMPNs) showed an increasing risk with OR = 1.65 (1.04–2.61) P = 0.0322 and OR = 3.87 (1.67–8.96) P = 0.0016 for mild and severe eosinophilia. Eosinophilia was in a similar fashion associated with chronic lymphatic leukemia (CLL), OR = 2.57 (1.50–4.43), P = 0.0006 and OR = 5.00 (1.57–15.94), P = 0.0065, and all‐cause death, OR of 1.16 (1.09–1.24), P < 0.0001 and 1.60 (1.35–1.91), P < 0.0001. We confirm associations between eosinophilia and HL and cMPNs, and in addition for the first time demonstrate a dose‐dependent association between eosinophilia and CLL as well as death. Unexplained eosinophilia should prompt clinicians to consider conditions where early diagnosis may improve prognosis. Am. J. Hematol. 88:843–847, 2013. © 2013 Wiley Periodicals, Inc.
BAALC overexpression retains its negative prognostic role across all cytogenetic risk groups in acute myeloid leukemia patients
Authors: Damiani Daniela , Tiribelli Mario , Franzoni Alessandra , Michelutti Angela , Fabbro Dora , Cavallin Margherita , Toffoletti Eleonora , Simeone Erica , Fanin Renato , Damante Giuseppe
Published: June 2013

Overexpression of brain and acute leukemia cytoplasmic (BAALC) gene confers poor prognosis in cytogenetically normal acute myeloid leukemia (AML) patients, while less defined is its role in AML with abnormal karyotype. We evaluated the effect of BAALC overexpression on outcome of 175 adult AML patients with different cytogenetic risks. Karyotype was favorable in 13, intermediate in 117 and unfavorable in 45 patients, respectively. Quantitative BAALC expression was determined by real‐time PCR, with cut off value set at 50th percentile. BAALC was overexpressed in 87/175 (50%) patients, without association with cytogenetic status. High BAALC was associated with unmutated NPM (P = 0.006) and CD34 positivity (P < 0.0001). Complete remission (CR) was attained in 111 patients (63%), and was maintained at 5 years in 52 ± 7%. BAALC overexpression had a negative impact on CR achievement (P = 0.04), while did not influence relapse probability. Median survival was 22 months with a 5‐years overall survival (OS) of 35%. Factors with a negative impact on OS were older age (P = 0.0001), unfavorable cytogenetic (P = 0.005), ABCG2 overexpression (P = 0.03) and high BAALC levels (P = 0.01). We observed a worse outcome in patients with high BAALC expression through all cytogenetic risk categories: 5‐years OS was 100% vs. 71% in patients with favorable cytogenetics (P = 0.05), 55% vs. 40% in cases with intermediate karyotype (P = 0.04) and 34% vs. 23% in unfavorable cytogenetic subgroup (P = 0.02). BAALC overexpression identified AML patients with poor prognosis in all cytogenetic groups. Though relatively rare, BAALC positivity in patients with favorable or unfavorable karyotype significantly worsened survival. Am. J. Hematol. 88:848–852, 2013. © 2013 Wiley Periodicals, Inc.
Asymmetric binuclear metallocene complexes and their application for olefin polymerization
Authors: Xu Sheng , Huang Jiling
Published: June 2013

Asymmetric double silylene‐bridged binuclear complexes [(η5‐RC5H4)MCl2]2[μ, μ‐(SiMe2)2(η5‐t‐BuC5H2)(η5‐C5H3)][R = H, M = Ti (1); R = Me, M = Ti (2); R = allyl, M = Ti(3); R = H, M = Zr (4); R = allyl, M= Zr (6)]; and [(η5‐C5H5)TiCl2]2[μ, μ‐(SiMe2)2(η5‐Me3SiC5H2)(η5‐C5H3)] (5) were synthesized by the reaction of (η5‐RC5H4) TiCl3 or (η5‐RC5H4)ZrCl3·DME (R = H, allyl) with [μ, μ‐ (SiMe2)2(η5‐t‐BuC5H2)(η5‐C5H3)] Li2 or [μ, μ‐(SiMe2)2(η5‐Me3Si C5H2)(η5‐C5H3)]Li2 in THF, and they were all well characterized by 1H NMR, MS, IR, and EA. When activated with methylaluminoxane (MAO), they are efficient catalysts for the polymerization of ethylene (Complex 4, 5.99 × 105 g‐PE/mol·Zr·h) and the polymer with multipeak broaden molecular weight distribution (PD = Mw/Mn) was obtained (polymer sample gained by complex 3, PD = 25.03). The copolymerization results indicate that 1‐hexene could incorporate into the growing PE chain with these complexes in the presence of MAO (Complex 4, 1.07 × 106 g‐PE/mol·Zr·h; 1‐hexene content, 1.57% mol). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2891–2900, 2013
Hydrophobically associating acrylamide‐based copolymer for chemically enhanced oil recovery
Authors: Ye Zhongbin , Feng Mingming , Gou Shaohua , Liu Man , Huang Ziyan , Liu Tongyi
Published: June 2013

A hydrophobically associating copolymer was prepared by free‐radical polymerization with acrylamide (AM), acrylic acid (AA), and N‐allyloctadec‐9‐enamide (NAE) as monomers. The structure was characterized by Fourier transform infrared spectroscopy, 1H‐NMR, 13C‐NMR, and scanning electron microscopy. The rheological experiments indicated that the copolymer possessed superior properties compared with partially hydrolyzed polyacryamide. It was found that an AM/AA/NAE/Tween‐80 system could effectively decrease the interfacial tension and reduce the surfactant loss caused by stratum adsorption in polymer–surfactant flooding. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2901–2911, 2013
Shear effect in beta‐phase induction of polypropylene in a single screw extruder
Authors: Navarro‐Pardo Fabiola , Laria Julio , Lozano Tomas , Morales‐Cepeda Ana B. , Lafleur Pierre G. , Sánchez‐Valdés Saul , Rodríguez‐González Francisco
Published: June 2013

In this work, we investigated the effect of four different configurations at the exit of a single‐screw extruder on the induction of beta phase in PP for four different rotational speeds. The configuration of a breaker plate with 120 orifices of 1‐mm diameter and 7‐mm length each, give the highest content of beta‐phase (56.92%), for a screw rotational speed of 20 rpm. It was due to the shear caused separation of the melt when it passes through the orifices of the breaker plate. The breaker plate of configuration 4 (breaker plate with the greatest number of orifices) provided the largest number of contacts between the melt and the orifice walls resulting in chain alignment. The results show that the beta‐phase can be induced in the polymer without any further additives, especially without any nucleating agents, but rather by using a special breaker plate configuration at the exit of the single‐screw extruder. The skin‐core structure of the polymer was only developed with one type of extruder configuration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2932–2937, 2013
Facile surface modification of PVDF microfiltration membrane by strong physical adsorption of amphiphilic copolymers
Authors: Peng Bo , Li Yuyan , Zhao Zhiguo , Chen Yongming , Han Charles C.
Published: June 2013

To endow the surface of poly(vinylidene fluoride) (PVDF) microfiltration (MF) membranes with hydrophilicity and antifouling property, physical adsorption of amphiphilic random copolymers of poly(ethylene glycol) methacrylate (PEGMA) and poly(methyl methacrylate) (PMMA) (P(PEGMA‐r‐MMA)) onto the PVDF membrane was performed. Scanning electron microscopy (SEM) images showed that the adsorption process had no influence on the membrane structure. Operation parameters including adsorption time, polymer concentration, and composition were explored in detail through X‐ray photoelectron spectroscopy (XPS), static water contact angle (CA), and water flux measurements. The results demonstrated that P(PEGMA‐r‐MMA) copolymers adsorbed successfully onto the membrane surface, and hydrophilicity of the PVDF MF membrane was greatly enhanced. The antifouling performance and adsorption stability were also characterized, respectively. It was notable that PVDF MF membranes modified by facile physical adsorption of P(PEGMA58‐r‐MMA33) even showed higher water flux and better antifouling property than the commercial hydrophilic PVDF MF membranes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3112–3121, 2013
Combined effect of relative humidity and temperature on dynamic viscoelastic properties and glass transition of poly(vinyl alcohol)
Authors: Hu Hongjiu , Zhang Xiaolong , He Yaolong , Guo Zhan‐sheng , Zhang Junqian , Song Yicheng
Published: June 2013

On the basis of the experimental studies on viscoelastic properties of poly vinyl alcohol (PVA) films at various relative humidity (RH) and temperature conditions by dynamic mechanical analysis (DMA), the influence of both temperature and RH on the glass transition are discussed and an improved property model is developed to relate the dynamic modulus to RH and temperature. The results indicate that (1) with increasing the RH, the storage modulus of PVA decrease remarkably, while both loss modulus and tanδ sharply increase to reach the peak and then markedly drops. The intensity of this variation is highly dependent upon temperature. (2) Moisture increase will cause the glass transition of PVA at isothermal condition and the transition point can be detected by glass transition relative humidity (RHg) that obtained by isothermal RH scans. (3) Similar to the relationship between Tg and RH, the RHg of PVA vary linearly with temperature. The state diagram of RHg versus temperatures is nearly consistent with that of Tg versus RH. (4)The present equation based on model of Mahieux and Reifsnider (Mahieux and Reifsnider, Polymer 2001, 42, 3281) can predict well the dynamic modulus of PVA at various RHs and temperatures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3161–3167, 2013
Effects of type of binder and conducting phase on the performance of solid‐state electrochemiluminescence composites
Authors: Safavi A. , Sedaghati F. , Shahbaazi H.
Published: June 2013

The electrochemiluminescence (ECL) of tris(2,2‐bipyridyl)ruthenium [Ru(bpy)3]2+ has received much attention. By immobilizing [Ru(bpy)3]2+ on an electrode surface, solid‐state ECL has several advantages over solution‐phase ECL, such as reduced amounts of costly reagent and a simplified experimental design. Herein, different types of solid‐state ECL sensors were fabricated and the performances of paraffin oil and two ionic liquids (ILs) as the binders were compared for the construction of solid‐state ECL. Scanning electron microscopy (SEM), CCD camera, UV–vis, fluorescence spectroscopy, electrochemistry and ECL were applied to characterize and evaluate the performance of the solid‐state composites. According to the obtained results, Ru–graphite/IL octyl pyridinium hexaflurophosphate (OPPF6) was introduced as a new solid‐state ECL with excellent properties such as simple preparation, low background current, fast electron‐transfer rate and good reproducibility and stability. Moreover, for a study of the effect of carbon structure on the performance of the electrode, graphite was replaced by multi‐walled carbon nanotubes (MWCNTs) and Ru–MWCNT/OPPF6 was constructed and its efficiency was compared with Ru–graphite/OPPF6 composite electrode. Copyright © 2013 John Wiley & Sons, Ltd.
Exploration of Sialic Acid Diversity and Biology Using Sialoglycan Microarrays
Authors: Deng Lingquan , Chen Xi , Varki Ajit
Published: June 2013

Sialic acids (Sias) are a group of α‐keto acids with a nine‐carbon backbone, which display many types of modifications in nature. The diversity of natural Sia presentations is magnified by a variety of glycosidic linkages to underlying glycans, the sequences and classes of such glycans, as well as the spatial organization of Sias with their surroundings. This diversity is closely linked to the numerous and varied biological functions of Sias. Relatively large libraries of natural and unnatural Sias have recently been chemically/chemoenzymatically synthesized and/or isolated from natural sources. The resulting sialoglycan microarrays have proved to be valuable tools for the exploration of diversity and biology of Sias. Here we provide an overview of Sia diversity in nature, the approaches used to generate sialoglycan microarrays, and the achievements and challenges arising. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 650–665, 2013.
Solution Phase Conformation and Proteolytic Stability of Amide‐Linked Neuraminic Acid Analogues
Authors: Saludes Jonel P. , Gregar Travis Q. , Monreal I. Abrrey , Cook Brandan M. , Danan‐Leon Lieza M. , Gervay‐Hague Jacquelyn
Published: June 2013

Amide‐linked homopolymers of sialic acid offer the advantages of stable secondary structure and increased bioavailability making them useful constructs for pharmaceutical design and drug delivery. Defining the structural characteristics that give rise to secondary structure in aqueous solution is challenging in homopolymeric material due to spectral overlap in NMR spectra. Having previously developed computational tools for heteroologomers with resolved spectra, we now report that application of these methods in combination with circular dichroism, NH/ND NMR exchange rates and nOe data has enabled the structural determination of a neutral, δ‐amide‐linked homopolymer of a sialic acid analogue called Neu2en. The results show that the inherent planarity of the pyranose ring in Neu2en brought about by the α,δ‐conjugated amide bond serves as the primary driving force of the overall conformation of the homooligomer. This peptide surrogate has an excellent bioavailability profile, with half‐life of ∼12 h in human blood serum, which offers a viable peptide scaffold that is resistant to proteolytic degradation. Furthermore, a proof‐of‐principle study illustrates that Neu2en oligomers are functionalizable with small molecule ligands using 1,3‐dipolar cycloaddition chemistry. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 686–696, 2013.
Visualization of the leakage of pancreatic juice using a chymotrypsin-activated fluorescent probe
Authors: Yamashita S , Sakabe M , Ishizawa T , Hasegawa K , Urano Y , Kokudo N
Published: June 2013

Background

Pancreatic fistula (PF) remains the most serious complication after digestive surgery. It is difficult to prevent because of the inability to visualize the leakage of pancreatic juice during surgery or to evaluate the protease activity of leaked fluid, which is responsible for PF formation.

Methods

The fluorescence intensities of a chymotrypsin probe (glutamyl-phenylalanine hydroxymethyl rhodamine green with added trypsin) in pancreatic juice and in intestinal or abdominal fluids drained after pancreatic resection were evaluated. The chymotrypsin probe was sprayed on to filter papers that had been placed on the resected pancreatic stump in patients undergoing pancreaticoduodenectomy or central pancreatectomy. The ability of this technique to visualize the leakage of pancreatic juice and predict postoperative PF formation was assessed.

Results

The fluorescence intensity of the chymotrypsin probe in 76 fluid samples correlated positively with amylase levels (rs = 0·678, P < 0·001). The fluorescence patterns of the pancreatic stump were classified grossly into the three types: duct (fluorescence signal visualized only on the stump of the main pancreatic duct, 16 patients), diffuse (ductal stump and surrounding pancreatic parenchyma, 7) and negative (no fluorescence signal, 7). Symptomatic PFs developed in 13 of 23 patients with duct- or diffuse-type fluorescence, but in none of the seven patients with negative-type fluorescence (P = 0·008).

Conclusion

The chymotrypsin probe enabled determination of the protease activity in drained pancreatic fluid samples and allowed real-time visualization of pancreatic juice leakage during surgery.
Comparative study on the excretion of vitexin‐4′′‐O‐glucoside in mice after oral and intravenous administration by using HPLC
Authors: Cai Shuang , Chen Yinghui , Zhang Wenjie , Ying Xixiang
Published: June 2013

The aim of the present study was to characterize the excretion of pure vitexin‐4”‐O‐glucoside (VOG) in mice following oral and intravenous administration at a dose of 30 mg/kg. A sensitive and specific HPLC method with hespridin as internal standard, a Diamonsil C18 column protected with a KR C18 guard column and a mixture consisting of methanol–acetonitrile–tetrahydrofuran–0.1% glacial acetic acid (6:2:18:74, v/v/v/v) as mobile phase was developed and validated for quantitative analysis in biological samples. VOG could be excreted as prototype in excreta including urine and feces after both routes of administration, and the cumulative excretion of VOG was 24.31 ± 11.10% (17.97 ± 5.59% in urinary excretion; 6.34 ± 5.51% in fecal excretion) following oral dosing and 5.66 ± 3.94% (4.78 ± 3.13% in urinary excretion; 0.88 ± 0.81% in fecal excretion) following intravenous dosing. The results showed that the elimination of VOG after the two routes was fairly low, which meant that VOG was metabolized as other forms and the elimination after oral dosing was almost 4.3‐fold that after intravenous dosing. For both routes of administration, VOG excreted as prototype in urine was much more than that in feces, nearly 2.83‐fold for oral administration and 5.43‐fold for intravenous administration, which should be attributed to enterohepatic circulation. Taken together, renal excretion was the dominant path of elimination of VOG for oral and intravenous administration in mice and biliary excretion contributed less. Copyright © 2013 John Wiley & Sons, Ltd.
A simple and accurate method to determine nitrite and nitrate in serum based on high‐performance liquid chromatography with fluorescence detection
Authors: Shu‐yu Zhan , Qing Shao , Li Liu , Xiao‐hui Fan
Published: June 2013

A simple method for accurate determination of nitrite and nitrate in serum was proposed to avoid the variation of nitrate reduction. For nitrite determination, serum samples were directly precipitated with methanol pre‐nitrate conversion, and then the supernatant reacted with 2,3‐diaminonaphthalene (DAN) to form 2,3‐naphthotriazole (NAT), which was quantitatively analyzed by high‐performance liquid chromatography coupled with fluorescence detection (HPLC‐FL). For nitrate determination, samples were firstly heated at 70°C for 10 min to inactivate endogenous reductase‐inhibiting proteins, then nitrate in the samples was quantitatively reduced to nitrite by reductase added experimentally. The difference in total nitrite concentrations between pre‐ and post‐nitrate conversion was used to calculate the amount of nitrate in the samples. In addition to good specificity, high sensitivity, satisfactory accuracy and reproducibility, our method is simple and suitable for the quantitative determination of nanomolar level of nitrite and nitrate in a large number of serum samples. Copyright © 2013 John Wiley & Sons, Ltd.
Post‐separation Fathering and Domestic Abuse: Challenges and Contradictions
Authors: Holt Stephanie
Published: June 2013

This paper explores the experience of post‐separation fathering, in the context of a prior history of domestic abuse from the perspectives of mothers, fathers, children and professionals participating in a three‐year doctoral research project. A mixed methodological research design conducted over two phases involved both the completion of survey questionnaires by 219 mothers and the participation in focus groups and individual interviews by children and young people, mothers, fathers and professionals. The findings highlight clear evidence of post‐separation contact facilitating the continued abuse of women and children. The findings also highlight a lack of attention to the parenting of abusive men who were identified as struggling to realise their fathering aspirations and take responsibility for the impact of their abusive behaviour on their children and ex‐partners. Particular constructions of family life are found to sustain the often unmonitored presence of abusive men in post‐separation family life. This paper concludes by asserting the need to prioritise the construction of fathers as ‘risk’ in the context of post‐separation father‐child contact. Doing so does not mean excluding fathers from children's lives; rather, what is critical is to find ways to ensure that abusive men can be ‘good enough’ fathers. Copyright © 2013 John Wiley & Sons, Ltd.

‘Clear evidence of post‐separation contact facilitating the continued abuse of women and children’

Key Practitioner Messages

Separation is not a ‘vaccine against domestic violence’, with women and children at risk of continued abuse in the post‐separation period.

Abusive men need to be held responsible for their abusive behaviour before the potential for safe contact can be considered.

All of the key players – mothers, children and fathers – may need support from the impact that domestic violence has on parenting capacity and family life.

‘Abusive men need to be held responsible for their abusive behaviour before the potential for safe contact can be considered’
Implementation of real‐time three‐dimensional transesophageal echocardiography for mitral balloon valvuloplasty
Authors: Eng Marvin H. , Salcedo Ernesto E. , Kim Michael , Quaife Robert A. , Carroll John D.
Published: June 2013

Background

Transthoracic (TTE) and intracardiac echocardiography (ICE) have both been established as modalities for imaging guidance in mitral balloon valvuloplasty (MBV). Real‐time three‐dimensional transesophageal echocardiography (RT3D‐TEE) improves depth resolution, characterization of pathology and visualization of interventional catheters and devices. Three‐dimensional imaging should enhance catheter navigation but improvements in procedural outcomes are not easily quantified. Using time from transseptal puncture to balloon inflation, procedure time and radiation exposure as surrogates for improvements linked to image guidance, we describe our early experience in implementing RT3D‐TEE during MBV, a prototypical left‐sided structural intervention.

Methods

Using a dedicated interventional procedures database, we reviewed the clinical and procedural variables of 70 consecutive cases of MBV utilizing either RT3D‐TEE or TTE combined with ICE from 12/2004 to 4/2009.

Results

The clinical characteristics of both groups were well matched and there was no difference in mean gradient reduction or complication rates. Fluoroscopy times (TTE/ICE 26.7 ± 5.6 min. vs. RT3D‐TEE 23.3 ± 6 min. P = 0.02) and radiation dose‐area product (TTE/ICE 216.2 ± 96.6 vs. RT3D‐TEE 171.5 ± 63.9) were lower with the RT3D‐TEE cohort. Time from 1st transseptal puncture attempt to 1st balloon inflation was found to be lower in the RT‐3DTEE cohort (TTE/ICE 36 ± 8 min vs. 28 ± 8 min P <0.01)

Conclusion

RT3D‐TEE is associated with expedited transseptal puncture and balloon catheter navigation as reflected in the decreased transseptal to balloon time. RT3D‐TEE is associated with less reliance on fluoroscopic navigation as compared to using TTE/ICE. This series demonstrates the feasibility and advantages of implementing RT3D‐TEE for MBV. © 2013 Wiley Periodicals, Inc.
Left main occlusion secondary to aortic root rupture following transcatheter aortic valve replacement managed by left main stenting
Authors: Kim Rebeca J. , McGehee Elizabeth , Mack Michael J.
Published: June 2013

Acute left main coronary occlusion secondary to a periaortic root hematoma secondary to annular rupture during transcatheter heart valve deployment is reported. © 2013 Wiley Periodicals, Inc.
Near‐Infrared‐Controlled, Targeted Hydrophobic Drug‐Delivery System for Synergistic Cancer Therapy
Authors: Yang Xinjian , Liu Zhen , Li Zhenhua , Pu Fang , Ren Jinsong , Qu Xiaogang
Published: June 2013

Hydrophobicity has been an obstacle that hinders the use of many anticancer drugs. A critical challenge for cancer therapy concerns the limited availability of effective biocompatible delivery systems for most hydrophobic therapeutic anticancer drugs. In this study, we have developed a targeted near‐infrared (NIR)‐regulated hydrophobic drug‐delivery platform based on gold nanorods incorporated within a mesoporous silica framework (AuMPs). Upon application of NIR light, the photothermal effect of the gold nanorods leads to a rapid rise in the local temperature, thus resulting in the release of the entrapped drug molecules. By integrating chemotherapy and photothermotherapy into one system, we have studied the therapeutic effects of camptothecin‐loaded AuMP‐polyethylene glycol‐folic acid nanocarrier. Results revealed a synergistic effect in vitro and in vivo, which would make it possible to enhance the therapeutic effect of hydrophobic drugs and decrease drug side effects. Studies have shown the feasibility of using this nanocarrier as a targeted and noninvasive remote‐controlled hydrophobic drug‐delivery system with high spatial/temperal resolution. Owing to these advantages, we envision that this NIR‐controlled, targeted drug‐delivery method would promote the development of high‐performance hydrophobic anticancer drug‐delivery system in future clinical applications.
Polynuclear Complexes with Alkoxo and Phenoxo Bridges from In Situ Generated Hydroxy‐Rich Schiff Base Ligands: Syntheses, Structures, and Magnetic Properties
Authors: Ding Caixia , Gao Chen , Ng Seikweng , Wang Bingwu , Xie Yongshu
Published: June 2013

Complexes of new Schiff base ligands generated in situ from the reaction of 1‐aminoglycerol, aldehydes, and metal ions are reported. [Cu4(HL1)4] (1) and [Ni4O(HL1)3(H2O)3)]⋅6 H2O⋅DMF⋅DMSO (2) have M4O4 cubane cores, with the L/M molar ratios of 4:4 and 3:4, respectively. [MnIII3MnIINaOCl4(HL1)3]⋅3 MeCN (3) has a unique pentanuclear trigonal propeller‐shaped MnIII3MnIINa core structure, and the coordination assemblies are linked by hydrogen bonds to afford a 3D channel structure. [Cu2(HL2)2] (4) has a bis(μ2‐alkoxo)‐bridged Cu2O2 core, with the binuclear species linked by hydrogen bonds to afford a 1D double‐chain. [Ni7(OH)2(OCH3)4(H2L3)2(MeOH)2(H2O)2]‐ (ClO4)2⋅10 H2O (5) has a heptanuclear structure containing heptadentate di‐Schiff base ligands, with the nickel(II) ions bridged by phenoxo, alkoxo, hydroxo, and methoxo groups to afford a very rare face‐sharing hexadruple defective cubane core with a Ni@Ni6 arrangement. The lattice water molecules are linked by hydrogen bonds to form helical chains, which are further hydrogen‐bonded to the coordination moieties to afford a 2D network. Variable temperature magnetic susceptibility measurements and nonlinear data‐fitting revealed that the “2+4” type of cubane complex 1 shows medium intradimeric ferromagnetic interactions and weak interdimeric ferromagnetic interactions. For complexes 2 and 5, coexistent ferro‐ and antiferromagnetic couplings afford a non‐zero spin ground state. However, compound 3 shows antiferromagnetic interactions between MnIII and MnII, and ferromagnetic interactions between the MnIII centers, resulting in a global antiferromagnetic behavior. In conclusion, the reaction of 1‐aminoglycerol with aldehydes and metal salts afforded polynuclear complexes with a rich structural diversity and remarkable magnetic behavior.
Electrospun Spinel LiNi0.5Mn1.5O4 Hierarchical Nanofibers as 5 V Cathode Materials for Lithium‐Ion Batteries
Authors: Liu Jun , Liu Wei , Ji Shaomin , Zhou Yichun , Hodgson Peter , Li Yuncang
Published: June 2013

Spinel LiNi0.5Mn1.5O4 hierarchical nanofibers with diameters of 200–500 nm and lengths of up to several tens of micrometers were synthesized using low‐cost starting materials by electrospinning combined with annealing. Well‐separated nanofiber precursors impede the growth and agglomeration of LiNi0.5Mn1.5O4 particles. The hierarchical nanofibers were constructed from attached LiNi0.5Mn1.5O4 nanooctahedrons with sizes ranging from 200 to 400 nm. It is proven that these LiNi0.5Mn1.5O4 hierarchical nanofibers exhibit a favorable electrochemical performance. At a 0.5 C (coulombic) rate, it shows an initial discharge capacity of 133 mA h g−1 with a capacity retention over 94 % after 30 cycles. Even at 2, 5, 10, and 15 C rates, it can still deliver a discharge capacity of 115, 100, 90, and 80 mA h g−1, respectively. Compared with self‐aggregated nanooctahedrons synthesized using common sol–gel methods, the LiNi0.5Mn1.5O4 hierarchical nanofibers exhibit a much higher capacity. This is owing to the fact that the self‐aggregation of the unique nanooctahedron‐in‐nanofiber structure has been greatly reduced because of the attachment of nanopolyhedrons in the long nanofibers. This unique microstructured cathode results in the large effective contact areas of the active materials, conductive additives and fully realize the advantage of nanomaterial‐based cathodes.