bluuebunny/crossref_metadata_2025 huggingface dataset:
Dust-ion-acoustic shock waves in a two-electron-temperature dusty plasma
Authors: MASUD M. M. , ASADUZZAMAN M. , MAMUN A. A.
Published: October 2012

Properties of dust-ion-acoustic shock waves (DIASWs) in an unmagnetized dusty plasma (containing inertial ions, Maxwellian electrons with two distinctive temperatures and negatively charged immobile dust) are investigated. The hydrodynamic equation for inertial ions has been used to derive the Burgers equation. The effects of two-electron-temperature and ion kinematic viscosity, which are found to significantly modify the basic features of the DIASWs, are discussed.
DGPS Enhancement to GPS NMEA Output Data: DGPS by Correction Projection to Position-Domain
Authors: Park Byungwoon , Lee Jeongkeun , Kim Younsil , Yun Ho , Kee Changdon
Published: October 2012

Most Differential Global Positioning System (DGPS) correction formats are based on range information, and thus typical DGPS systems can be implemented only on correction message-readable or raw observable-providing devices. There is no other way to improve an already-calculated position than a ‘block shift technique’, which has a very limited applicability. This paper suggests an algorithm to project measurement correction directly to position domain data without requiring raw pseudorange data. By post-processing methodology, we evaluated the performance of our new algorithm compared to conventional DGPS, which requires raw pseudorange data; the observed difference between them was only 0·1 mm . The proposed correction projection algorithm can be used with commercial off-the-shelf receivers that provide National Marine Electronics Association (NMEA) format data. Our testing with a U-blox LEA-5H receiver resulted in a drastic reduction of horizontal Root Mean Square (RMS) error from 4·75 m to 1·09 m.
Impaired Decision-Making as a Young Adult Outcome of Girls Diagnosed with Attention-Deficit/Hyperactivity Disorder in Childhood
Authors: Miller Meghan , Sheridan Margaret , Cardoos Stephanie L. , Hinshaw Stephen P.
Published: October 2012

We examined decision-making in young adulthood in a follow-up study of females diagnosed with attention-deficit/hyperactivity disorder (ADHD) between 6 and 12 years. Participants with childhood ADHD (n = 114) and matched comparison females (n = 77), followed prospectively for 10 years, performed the Iowa Gambling Task (IGT) at ages 17–25 years. This task assesses preference for high-reward/high-risk chances that result in lower overall gains (disadvantageous decks of cards) compared to low-reward/low-risk chances that result in higher overall gains (advantageous decks of cards). Relative to comparison participants, young adult females with a history of ADHD did not increase their preference for advantageous decks across time blocks, suggesting difficulties in learning to change behavior over the course of the IGT. Overall, childhood diagnoses of ADHD were associated with disadvantageous decision-making in young adulthood. These results extend findings on decision-making in males with ADHD by demonstrating comparable levels of impairment in an all-female sample. (JINS, 2013, 19, 1–5)
Genetic variability and interrelationships of phenological, physicochemical and cooking quality traits in chickpea
Authors: Tripathi Shailesh , Sridhar Vindla , Jukanti Aravind K. , Suresh Kamatam , Rao B. V. , Gowda C. L. L. , Gaur Pooran M.
Published: October 2012

Eighty-six chickpea (Cicer arietinum L.) genotypes, including 44 Kabuli type and 42 Desi type, were evaluated for their phenological, physicochemical and cooking quality traits. There were significant differences among the genotypes for days to 50% flowering (34–81 d), days to maturity (85–122 d), number of pods per plant (13–66), number of seeds per plant (15–85), 100-seed weight (10.5–58.6 g), seed yield (561–1852 kg/ha), hydration capacity (0.11–0.68 g water/seed), hydration index (0.80–1.21), swelling capacity (0.11–0.7 ml/seed), seed volume (0.1–0.52 ml/seed) and cooking time (38–125 min). The Desi and Kabuli types of chickpea differed significantly from each other for all the traits except for hydration index, swelling index and cooking time. High heritability coupled with high genetic advance was recorded for 100-seed weight, hydration capacity, swelling capacity and seed volume in both Desi and Kabuli genotypes. Seed size (100-seed weight and seed volume) showed significant positive correlations with hydration capacity and swelling capacity. Cooking time did not show any significant positive or negative correlation with any of the traits studied, including seed size, indicating that other additional factors may be involved in controlling cooking time. The results of this study indicate that it is possible to develop cultivars with faster cooking time in both Kabuli and Desi types and in all seed size categories.
Dichotomizing rating scale scores in psychiatry: a bad idea?
Authors: Purgato M. , Barbui C.
Published: October 2012

In psychiatry, the use of rating scales as measures of outcome in clinical trials allows us to generate continuous outcome data, where each individual's outcome is measured in numbers. Continuous outcomes can be divided into two categories, such as improved and not improved, or may be kept continuous. This article briefly presents the main advantages and disadvantages of these two approaches, which are commonly employed in the analyses of rating scale scores in clinical trials and systematic reviews.
Improvements in the CMIP5 simulations of ENSO‐SSTA meridional width
Authors: Zhang Wenjun , Jin Fei‐Fei
Published: October 2012

The recent study demonstrated the existence of a systematical narrow bias in the simulated El Niño‐Southern Oscillation (ENSO) meridional width of surface temperature anomaly (SSTA) of ENSO by the models participating in Phase 3 of the Coupled Model Inter‐comparison Project (CMIP3). The current models developed for Phase 5 of the CMIP (CMIP5) still have this narrow bias in ENSO width relative to the observation, but with a modest improvement over previous models. The improvement can partly be attributed to a better simulation in trade wind, and partly to a better simulation in ENSO period. It has also been demonstrated that the models with a better performance in ENSO width tend to simulate the precipitation response to ENSO over the off‐equatorial eastern Pacific more realistically.
Long‐lasting convective systems in the outer region of tropical cyclones in the western North Pacific
Authors: Lee Cheng‐Shang , Chen Buo‐Fu , Elsberry Russell L.
Published: October 2012

Long‐lasting mesoscale convective systems (MCSs) may occur in the outer region of tropical cyclones in the western North Pacific, especially in conjunction with the southwest monsoon as in the case of Typhoon Morakot that caused great flooding and landslides in Taiwan. These “outer‐MCSs” are linear convective systems that develop from distant rainbands, have a large cold cloud shield, and last more than six hours. These outer‐MCSs are important for typhoon rainfall forecasting because of the torrential rainfall when they interact with land and terrain to produce serious flooding that is separate from the rainfall near the center. A total of 109 outer‐MCSs that occurred during 1999–2009 are identified using infrared and passive microwave images. About 22% of all typhoons in the western North Pacific have at least one outer‐MCS during their life cycle. In 85% of the QuikSCAT oceanic 10‐m wind observations of outer‐MCSs, positive shear vorticity on the left side of mesoscale surface jets below the stratiform precipitation regions may be contributing to the continuous formation of new convective cells.
Changes in thermospheric temperature induced by high‐speed solar wind streams
Authors: Gardner Larry , Sojka Jan J. , Schunk Robert W. , Heelis Rod
Published: October 2012

During high‐speed stream (HSS) events the solar wind speed increases, and the cross polar cap potential increases, leading to increased Joule heating at high latitudes. The heat input at high latitudes heats the polar regions, which then conducts to lower latitudes, producing global heating. The heating occurs during the risetime of the cross polar cap potential and throughout the period of high cross polar cap potential as seen in our simulation. These simulations are performed using the Utah State University global thermosphere model driven by Joule heating rates that are consistent with electric fields observed by DMSP‐15 observations of HSS events. Cooling occurs as the cross polar cap potential decreases and continues for several days after the cross polar cap potential has returned to background values. Polar cap ionospheric observations are compared to model simulations of heating and cooling, providing evidence that the thermospheric model is capturing the HSS energy input and the post‐HSS multiday return to pre‐HSS conditions. The HSS heating can be as high as 100 K (as seen from both the model and the data) at high latitudes, with a corresponding, but lower, global increase in thermospheric temperature.
Rain, rock moisture dynamics, and the rapid response of perched groundwater in weathered, fractured argillite underlying a steep hillslope
Authors: Salve Rohit , Rempe Daniella M. , Dietrich William E.
Published: October 2012

Various field studies have concluded that shallow groundwater in weathered bedrock underlying hillslopes can contribute to both base and stormflow and thus dominate runoff. The processes associated with recharge from the ground surface, through this unsaturated zone, have received little study, yet they influence runoff dynamics, the chemical evolution of water, and moisture availability. Here we use five measurement systems to document soil and rock moisture dynamics within a 4000 m2zero‐order basin in which all runoff occurs through weathered argillite. At this site, the weathered bedrock zone (in which the groundwater fluctuates by 8 m seasonally) varies in depth from ∼4 m at the base of the hillslope to nearly 19 m near the hill top. An aggregate‐rich, porous, 0.5 m thick soil overlies the weathered bedrock. We find that during the first rains of the wet season, water rapidly travels meters into the weathered bedrock zone. Consistently, however, groundwater at some places responds quickly to the first major storm, well before the wetting front has been detected much beyond about 1 m. Furthermore, throughout the wet season, the lower portion of the unsaturated weathered bedrock shows little or no moisture change. These observations suggest a fracture‐dominated flow path, leading to a highly variably groundwater response across the hillslope for a given storm. Seasonal changes in rock moisture content are greatest in the first 5 to 10 m depth and may exceed the magnitude of moisture changes in the soil, suggesting that it could constitute a significant unmapped moisture reservoir.
A novel transcriptional regulator, Sll1130, negatively regulates heat-responsive genes in Synechocystis sp. PCC6803
Authors: Krishna Pilla Sankara , Rani Balaga Radha , Mohan M. Karthik , Suzuki Iwane , Shivaji Sisinthy , Prakash Jogadhenu S. S.
Published: October 2012

A conserved hypothetical protein, Sll1130, is a novel transcription factor that regulates the expression of major heat-responsive genes in Synechocystis sp. PCC6803. Synechocystis exhibited an increased thermotolerance due to disruption of sll1130. Δsll1130 cells recovered much faster than wild-type cells after they were subjected to heat shock (50°C) for 30 min followed by recovery at 34°C for 48 h. In Δsll1130 cultures, 70% of the cells were viable compared with the wild-type culture in which only 30% of the cells were viable. DNA microarray analysis revealed that in Δsll1130, expression of the heat-responsive genes such as htpG, hspA, isiA, isiB and several hypothetical genes were up-regulated. Sll1130 binds to a conserved inverted-repeat (GGCGATCGCC) located in the upstream region of the above genes. In addition, both the transcript and protein levels of sll1130 were immediately down-regulated upon shift of wild-type cells from 34 to 42°C. Collectively the results of the present study suggest that Sll1130 is a heat-responsive transcriptional regulator that represses the expression of certain heat-inducible genes at optimum growth temperatures. Upon heat shock, a quick drop in the Sll1130 levels leads to de-repression of the heat-shock genes and subsequent thermal acclimation. On the basis of the findings of the present study, we present a model which describes the heat-shock response involving Sll1130.
N-Myristoylation is essential for protein phosphatases PPM1A and PPM1B to dephosphorylate their physiological substrates in cells
Authors: Chida Toko , Ando Masakatsu , Matsuki Tasuku , Masu Yutaro , Nagaura Yuko , Takano-Yamamoto Teruko , Tamura Shinri , Kobayashi Takayasu
Published: October 2012

PPM [metal-dependent protein phosphatase, formerly called PP2C (protein phosphatase 2C)] family members play essential roles in regulating a variety of signalling pathways. While searching for protein phosphatase(s) that act on AMPK (AMP-activated protein kinase), we found that PPM1A and PPM1B are N-myristoylated and that this modification is essential for their ability to dephosphorylate the α subunit of AMPK (AMPKα) in cells. N-Myristoylation was also required for two other functions of PPM1A and PPM1B in cells. Although a non-myristoylated mutation (G2A) of PPM1A and PPM1B prevented membrane association, this relocalization did not likely cause the decreased activity towards AMPKα. In in vitro experiments, the G2A mutants exhibited reduced activities towards AMPKα, but much higher specific activity against an artificial substrate, PNPP (p-nitrophenyl phosphate), compared with the wild-type counterparts. Taken together, the results of the present study suggest that N-myristoylation of PPM1A and PPM1B plays a key role in recognition of their physiological substrates in cells.
The promise and challenge of systems biology in translational medicine
Authors: Thongboonkerd Visith
Published: October 2012

Abnormalities in clinical parameters and routine laboratory tests are frequently detected at late stages of many diseases (too late to cure or to prevent life-threatening complications). Hence earlier diagnostic and prognostic markers are needed for decision making and improving therapeutic outcome. In the present issue of Clinical Science, Rudiger and co-workers report findings from a transcriptomic study, which revealed that changes in transcripts involved in amino-sugar metabolism, p53-dependent cell-cycle arrest, β-adrenergic signalling and intracellular calcium cycling in cardiac tissue of rats with early sepsis could discriminate survivors from non-survivors. These findings underscore the great potential of systems biology in translational medicine. However, further investigations should be done to make the benchside results more feasible for routine clinical practice.
Supervision
: The New Clinical Supervisor: Tools for the Medical Setting
Authors: Lulai Rebecca , DeRuiter Mark
Published: October 2012

Placement of graduate student clinicians in medical environments continues to serve as an ongoing challenge for many universities. This article addresses five questions, proposed by clinical supervisors, with focus on maintaining productivity while a student is present. Specific emphasis is given to preparations that can occur before the student arrives at the practicum location. The authors provide practical suggestions and templates in the appendices.
Traumatic Brain Injury: A Trauma Surgeon's Perspective
Authors: Guillamondegui Oscar D.
Published: October 2012

Traumatic brain injury (TBI) is a serious epidemic in the United States. It affects patients of all ages, race, and socioeconomic status (SES). The current care of these patients typically manifests after sequelae have been identified after discharge from the hospital, long after the inciting event. The purpose of this article is to introduce the concept of identification and management of the TBI patient from the moment of injury through long-term care as a multidisciplinary approach. By promoting an awareness of the issues that develop around the acutely injured brain and linking them to long-term outcomes, the trauma team can initiate care early to alter the effect on the patient, family, and community. Hopefully, by describing the care afforded at a trauma center and by a multidisciplinary team, we can bring a better understanding to the armamentarium of methods utilized to treat the difficult population of TBI patients.
Understanding the Process of Backsourcing: Two Cases of Process and Product Backsourcing in Europe
Authors: Kotlarsky Julia , Bognar Lars
Published: October 2012

Backsourcing, defined generally as bringing services outsourced to a third party back in-house, is now a growing phenomenon. The decision to backsource has several significant implications for an organization, as it requires the organization to manage organizational change, reintegrate knowledge, and develop new capabilities and competences. Taking into account there is very limited empirical evidence of how to successfully accomplish the backsourcing process, two case studies included in this teaching case offer additional insight into the process of backsourcing. To prepare students for case analysis, this teaching case starts by describing the backsourcing phenomenon, followed by an overview of the backsourcing trend, and includes a brief review of the relevant literature that mainly focuses on backsourcing decisions and touches on critical success factors for implementing a backsourcing initiative. This is followed by two case studies that describe two essentially different examples of backsourcing. The first case study (MediaCorp) deals with the example of backsourcing IT hosting services, which is considered a business process, whereas the second case study (ITServCorp) talks about bringing an IT product development back in-house. However, regardless of the nature of the backsourced activity, analysis of these two cases allows deeper understanding of the process through which the backsourcing initiative has been implemented. Therefore, while each case can be used separately to analyze different aspects of backsourcing, they also can be analyzed in a comparative manner to better understand the process of backsourcing.
Feeding level and dietary energy source have no effect on embryo survival in gilts, despite changes in systemic progesterone levels
Authors: Athorn R. Z. , Stott P. , Bouwman E. G. , Edwards A. C. , Blackberry M. A. , Martin G. B. , Langendijk P.
Published: October 2012

This study was designed to assess the effect of feeding level and dietary energy source on luteal function, systemic progesterone concentration and embryo survival in gilts during early gestation. At Day 0 of pregnancy, 104 gilts were allocated to one of four experimental diets (LStarch: 1.2 × maintenance requirement (M) Starch diet (43.3% starch), n = 31; HStarch: 2.4 × M Starch diet (43.3% starch), n = 21; HFat: 2.4 × M Fat diet (13.5% fat), n = 23; and HFibre: 2.4 × M Fibre diet (7.2% fibre), n = 23). On Day 5 of gestation, no significant difference in circulating concentration of systemic progesterone was seen among the treatments. However, on Day 15 of pregnancy, gilts on the HStarch diet had a significantly lower concentration of systemic progesterone than did gilts on both the LStarch and HFat diets (P < 0.05; 24.8 ± 2.4 v. 32.7 ± 2.4 and 36.1 ± 2.1 ng/mL, respectively). At Day 35 of gestation, there was also a tendency for gilts on the HStarch and HFat diets to have a higher total luteal weight than for gilts on the LStarch diets (7.2 ± 0.2 and 7.1 ± 0.2 v. 6.7 ± 0.2 g (P < 0.05)). No difference in embryo survival was seen among the treatments. From the present study, we can conclude that altering feeding level and dietary energy source did not affect embryo survival, despite the fact that systemic progesterone concentrations were affected on Day 15 of gestation. Also, luteal weight was greater for those gilts on the high feeding level than for those on the low feeding level when fed the same energy source.
InCl3 Catalysed One-Pot Synthesis of Substituted Pyrroles and 2-Pyrones
Authors: Mahato Sanjit K. , Vinayagam Jayaraman , Dey Sumit , Timiri Ajay K. , Chatterjee Sourav , Jaisankar Parasuraman
Published: October 2012

An efficient InCl3 catalysed one-pot strategy has been developed for the synthesis of tetra-substituted pyrroles and tri-substituted 2-pyrones in very good yields. Tetra-substituted pyrroles were prepared from 1,4-enediones and β-dicarbonyls employing NH4OAc as a nitrogen source, through a combination of Michael addition and Paal–Knorr methods. Tri-substituted 2-pyrones were synthesised from 1,4-ynediones and appropriate β-dicarbonyls using a sequential Michael addition and 6-exo-trig cyclisation.
Poorer breeding by little penguins near Perth, Western Australia is correlated with above average sea surface temperatures and a stronger Leeuwin Current
Authors: Cannell Belinda L. , Chambers Lynda E. , Wooller Ron D. , Bradley J. Stuart
Published: October 2012

Using 20 years of data (1986 to 2008), we examined relationships between oceanographic variables (Fremantle sea level (FSL) – a proxy for the strength of the Leeuwin Current – and sea surface temperature (SST)) and five measures of little penguin, Eudyptula minor, breeding performance near Perth, Western Australia: namely (1) the laying date, (2) the number of chicks produced per pair, (3) the proportion of eggs that hatched, (4) the overall breeding success, defined as the proportion of total eggs laid that resulted in successful fledglings and (5) chick mass at fledging. The next three years of data (2009 to 2011) were used to test the performance of our statistical predictive models. FSL provided more accurate predictions of timing of laying, whereas SST provided more accurate predictions of breeding success. A later end to laying was associated with a high FSL during the summer (December to February) before breeding. Higher SSTs in the pre-breeding period from April to May corresponded to reduced breeding success, with lower fledgling success, fewer chicks per pair and generally a lower mean mass of chicks at fledging. The models predict that future oceanographic warming is expected to reduce the breeding success of this colony of little penguins.
Sulfur record of rising and falling marine oxygen and sulfate levels during the Lomagundi event
Authors: Planavsky Noah J. , Bekker Andrey , Hofmann Axel , Owens Jeremy D. , Lyons Timothy W.
Published: October 2012

Carbonates from approximately 2.3–2.1 billion years ago show markedly positive δ
13
C values commonly reaching and sometimes exceeding +10‰. Traditional interpretation of these positive δ
13
C values favors greatly enhanced organic carbon burial on a global scale, although other researchers have invoked widespread methanogenesis within the sediments. To resolve between these competing models and, more generally, among the mechanisms behind Earth’s most dramatic carbon isotope event, we obtained coupled stable isotope data for carbonate carbon and carbonate-associated sulfate (CAS). CAS from the Lomagundi interval shows a narrow range of δ
34
S values and concentrations much like those of Phanerozoic and modern marine carbonate rocks. The δ
34
S values are a close match to those of coeval sulfate evaporites and likely reflect seawater composition. These observations are inconsistent with the idea of diagenetic carbonate formation in the methanic zone. Toward the end of the carbon isotope excursion there is an increase in the δ
34
S values of CAS. We propose that these trends in C and S isotope values track the isotopic evolution of seawater sulfate and reflect an increase in pyrite burial and a crash in the marine sulfate reservoir during ocean deoxygenation in the waning stages of the positive carbon isotope excursion.
High-resolution, low-dose phase contrast X-ray tomography for 3D diagnosis of human breast cancers
Authors: Zhao Yunzhe , Brun Emmanuel , Coan Paola , Huang Zhifeng , Sztrókay Aniko , Diemoz Paul Claude , Liebhardt Susanne , Mittone Alberto , Gasilov Sergei , Miao Jianwei , Bravin Alberto
Published: October 2012

Mammography is the primary imaging tool for screening and diagnosis of human breast cancers, but ∼10–20% of palpable tumors are not detectable on mammograms and only about 40% of biopsied lesions are malignant. Here we report a high-resolution, low-dose phase contrast X-ray tomographic method for 3D diagnosis of human breast cancers. By combining phase contrast X-ray imaging with an image reconstruction method known as equally sloped tomography, we imaged a human breast in three dimensions and identified a malignant cancer with a pixel size of 92 μm and a radiation dose less than that of dual-view mammography. According to a blind evaluation by five independent radiologists, our method can reduce the radiation dose and acquisition time by ∼74% relative to conventional phase contrast X-ray tomography, while maintaining high image resolution and image contrast. These results demonstrate that high-resolution 3D diagnostic imaging of human breast cancers can, in principle, be performed at clinical compatible doses.
Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution
Authors: Fonseca-Azevedo Karina , Herculano-Houzel Suzana
Published: October 2012

Despite a general trend for larger mammals to have larger brains, humans are the primates with the largest brain and number of neurons, but not the largest body mass. Why are great apes, the largest primates, not also those endowed with the largest brains? Recently, we showed that the energetic cost of the brain is a linear function of its numbers of neurons. Here we show that metabolic limitations that result from the number of hours available for feeding and the low caloric yield of raw foods impose a tradeoff between body size and number of brain neurons, which explains the small brain size of great apes compared with their large body size. This limitation was probably overcome in
Homo erectus
with the shift to a cooked diet. Absent the requirement to spend most available hours of the day feeding, the combination of newly freed time and a large number of brain neurons affordable on a cooked diet may thus have been a major positive driving force to the rapid increased in brain size in human evolution.
Functional MYCN signature predicts outcome of neuroblastoma irrespective of
MYCN
amplification
Authors: Valentijn Linda J. , Koster Jan , Haneveld Franciska , Aissa Rachida Ait , van Sluis Peter , Broekmans Marloes E. C. , Molenaar Jan J. , van Nes Johan , Versteeg Rogier
Published: October 2012

Neuroblastoma is a pediatric tumor of the sympathetic nervous system.
MYCN
(V-myc myelocytomatosis viral-related oncogene, neuroblastoma derived [avian]) is amplified in 20% of neuroblastomas, and these tumors carry a poor prognosis. However, tumors without
MYCN
amplification also may have a poor outcome. Here, we identified downstream targets of MYCN by shRNA-mediated silencing MYCN in neuroblastoma cells. From these targets, 157 genes showed an expression profile correlating with MYCN mRNA levels in NB88, a series of 88 neuroblastoma tumors, and therefore represent in vivo relevant MYCN pathway genes. This 157-gene signature identified very poor prognosis tumors in NB88 and independent neuroblastoma cohorts and was more powerful than
MYCN
amplification or
MYCN
expression alone. Remarkably, this signature also identified poor outcome of a group of tumors without
MYCN
amplification. Most of these tumors have low MYCN mRNA levels but high nuclear MYCN protein levels, suggesting stabilization of MYCN at the protein level. One tumor has an
MYC
amplification and high
MYC
expression. Chip-on-chip analyses showed that most genes in this signature are directly regulated by MYCN. MYCN induces genes functioning in cell cycle and DNA repair while repressing neuronal differentiation genes. The functional MYCN-157 signature recognizes classical neuroblastoma with
MYCN
amplification, as well as a newly identified group marked by MYCN protein stabilization.
Adaptation to a new environment allows cooperators to purge cheaters stochastically
Authors: Waite Adam James , Shou Wenying
Published: October 2012

Cooperation via production of common goods is found in diverse life forms ranging from viruses to social animals. However, natural selection predicts a “tragedy of the commons”: Cheaters, benefiting from without producing costly common goods, are more fit than cooperators and should destroy cooperation. In an attempt to discover novel mechanisms of cheater control, we eliminated known ones using a yeast cooperator–cheater system engineered to supply or exploit essential nutrients. Surprisingly, although less fit than cheaters, cooperators quickly dominated a fraction of cocultures. Cooperators isolated from these cocultures were superior to the cheater isolates they had been cocultured with, even though these cheaters were superior to ancestral cooperators. Resequencing and phenotypic analyses revealed that evolved cooperators and cheaters all harbored mutations adaptive to the nutrient-limited cooperative environment, allowing growth at a much lower concentration of nutrient than their ancestors. Even after the initial round of adaptation, evolved cooperators still stochastically dominated cheaters derived from them. We propose the “adaptive race” model: If during adaptation to an environment, the fitness gain of cooperators exceeds that of cheaters by at least the fitness cost of cooperation, the tragedy of the commons can be averted. Although cooperators and cheaters sample from the same pool of adaptive mutations, this symmetry is soon broken: The best cooperators purge cheaters and continue to grow, whereas the best cheaters cause rapid self-extinction. We speculate that adaptation to changing environments may contribute to the persistence of cooperative systems before the appearance of more sophisticated mechanisms of cheater control.
Transcription factor ATF5 is required for terminal differentiation and survival of olfactory sensory neurons
Authors: Wang Shu-Zong , Ou Jianhong , Zhu Lihua J. , Green Michael R.
Published: October 2012

Activating transcription factor 5 (ATF5) is a member of the ATF/cAMP response element-binding family of transcription factors, which compose a large group of basic region leucine zipper proteins whose members mediate diverse transcriptional regulatory functions. ATF5 has a well-established prosurvival activity and has been found to be overexpressed in several human cancers, in particular glioblastoma. However, the role(s) of ATF5 in development and normal physiology are unknown. Here we address this issue by deriving and characterizing homozygousAtf5knockout mice. We find thatAtf5−/−pups die neonatally, which, as explained below, is consistent with an olfactory defect resulting in a competitive suckling deficit. We show thatAtf5is highly expressed in olfactory sensory neurons (OSNs) in the main olfactory epithelium starting from embryonic stage 11.5 through adulthood. Immunostaining experiments with OSN-specific markers reveal that ATF5 is expressed in some immature OSNs and in all mature OSNs. Expression profiling and immunostaining experiments indicate that loss ofAtf5leads to a massive reduction in mature OSNs resulting from a differentiation defect and the induction of apoptosis. Ectopic expression ofAtf5in neural progenitor cells induces expression of multiple OSN-specific genes. Collectively, our results suggest a model in whichAtf5is first expressed in immature OSNs and the resultant ATF5 functions to promote differentiation into mature OSNs. Thus, ATF5 is required for terminal differentiation and survival of OSNs.
Fiber orientation-dependent white matter contrast in gradient echo MRI
Authors: Wharton Samuel , Bowtell Richard
Published: October 2012

Recent studies have shown that there is a direct link between the orientation of the nerve fibers in white matter (WM) and the contrast observed in magnitude and phase images acquired using gradient echo MRI. Understanding the origin of this link is of great interest because it could offer access to a new diagnostic tool for investigating tissue microstructure. Since it has been suggested that myelin is the dominant source of this contrast, creating an accurate model for characterizing the effect of the myelin sheath on the evolution of the NMR signal is an essential step toward fully understanding WM contrast. In this study, we show by comparison of the results of simulations and experiments carried out on human subjects at 7T, that the magnitude and phase of signals acquired from WM in vivo can be accurately characterized by (
i
) modeling the myelin sheath as a hollow cylinder composed of material having an anisotropic magnetic susceptibility that is described by a tensor with a radially oriented principal axis, and (
ii
) adopting a two-pool model in which the water in the sheath has a reduced
T
2
relaxation time and spin density relative to its surroundings, and also undergoes exchange. The accuracy and intrinsic simplicity of the hollow cylinder model provides a versatile framework for future exploitation of the effect of WM microstructure on gradient echo contrast in clinical MRI.
Simplified mechanism for new particle formation from methanesulfonic acid, amines, and water via experiments and ab initio calculations
Authors: Dawson Matthew L. , Varner Mychel E. , Perraud Véronique , Ezell Michael J. , Gerber R. Benny , Finlayson-Pitts Barbara J.
Published: October 2012

Airborne particles affect human health and significantly influence visibility and climate. A major fraction of these particles result from the reactions of gaseous precursors to generate low-volatility products such as sulfuric acid and high-molecular weight organics that nucleate to form new particles. Ammonia and, more recently, amines, both of which are ubiquitous in the environment, have also been recognized as important contributors. However, accurately predicting new particle formation in both laboratory systems and in air has been problematic. During the oxidation of organosulfur compounds, gas-phase methanesulfonic acid is formed simultaneously with sulfuric acid, and both are found in particles in coastal regions as well as inland. We show here that: (i) Amines form particles on reaction with methanesulfonic acid, (ii) water vapor is required, and (iii) particle formation can be quantitatively reproduced by a semiempirical kinetics model supported by insights from quantum chemical calculations of likely intermediate clusters. Such an approach may be more broadly applicable in models of outdoor, indoor, and industrial settings where particles are formed, and where accurate modeling is essential for predicting their impact on health, visibility, and climate.
Structural analysis of human Cdc20 supports multisite degron recognition by APC/C
Authors: Tian Wei , Li Bing , Warrington Ross , Tomchick Diana R. , Yu Hongtao , Luo Xuelian
Published: October 2012

The anaphase-promoting complex/cyclosome (APC/C) promotes anaphase onset and mitotic exit through ubiquitinating securin and cyclin B1. The mitotic APC/C activator, the cell division cycle 20 (Cdc20) protein, directly interacts with APC/C degrons––the destruction (D) and KEN boxes. APC/C
Cdc20
is the target of the spindle checkpoint. Checkpoint inhibition of APC/C
Cdc20
requires the binding of a BubR1 KEN box to Cdc20. How APC/C recognizes substrates is not understood. We report the crystal structures of human Cdc20 alone or bound to a BubR1 KEN box. Cdc20 has a disordered N-terminal region and a C-terminal WD40 β propeller with a preformed KEN-box-binding site at its top face. We identify a second conserved surface at the side of the Cdc20 β propeller as a D-box-binding site. The D box of securin, but not its KEN box, is critical for securin ubiquitination by APC/C
Cdc20
. Although both motifs contribute to securin ubiquitination by APC/C
Cdh1
, securin mutants lacking either motif are efficiently ubiquitinated. Furthermore, D-box peptides diminish the ubiquitination of KEN-box substrates by APC/C
Cdh1
, suggesting possible competition between the two motifs. Our results indicate the lack of strong positive cooperativity between the two degrons of securin. We propose that low-cooperativity, multisite target recognition enables APC/C to robustly ubiquitinate diverse substrates and helps to drive cell cycle oscillations.
T-cell receptor (TCR) interaction with peptides that mimic nickel offers insight into nickel contact allergy
Authors: Yin Lei , Crawford Frances , Marrack Philippa , Kappler John W. , Dai Shaodong
Published: October 2012

T cell-mediated allergy to Ni++is one of the most common forms of allergic contact dermatitis, but how the T-cell receptor (TCR) recognizes Ni++is unknown. We studied a TCR from an allergic patient that recognizes Ni++bound to the MHCII molecule DR52c containing an unknown self-peptide. We identified mimotope peptides that can replace both the self-peptide and Ni++in this ligand. They share a p7 lysine whose εNH2group is surface-exposed when bound to DR52c. Whereas the TCR uses germ-line complementary-determining region (CDR)1/2 amino acids to dock in the conventional diagonal mode on the mimotope–DR52c complex, the interface is dominated by the TCR Vβ CDR3 interaction with the p7 lysine. Mutations in the TCR CDR loops have similar effects on the T-cell response to either the mimotope or Ni++ligand. We suggest that the mimotope p7 lysine mimics Ni++in the natural TCR ligand and that MHCII β-chain flexibility in the area around the peptide p7 position forms a common site for cation binding in metal allergies.
Functional eukaryotic nuclear localization signals are widespread in terminal proteins of bacteriophages
Authors: Redrejo-Rodríguez Modesto , Muñoz-Espín Daniel , Holguera Isabel , Mencía Mario , Salas Margarita
Published: October 2012

A number of prokaryotic proteins have been shown to contain nuclear localization signals (NLSs), although its biological role remains sometimes unclear. Terminal proteins (TPs) of bacteriophages prime DNA replication and become covalently linked to the genome ends. We predicted NLSs within the TPs of bacteriophages from diverse families and hosts and, indeed, the TPs of Φ29, Nf, PRD1, Bam35, and Cp-1, out of seven TPs tested, were found to localize to the nucleus when expressed in mammalian cells. Detailed analysis of Φ29 TP led us to identify a bona fide NLS within residues 1–37. Importantly, gene delivery into the eukaryotic nucleus is enhanced by the presence of Φ29 TP attached to the 5′ DNA ends. These findings show a common feature of TPs from diverse bacteriophages targeting the eukaryotic nucleus and suggest a possible common function by facilitating the horizontal transfer of genes between prokaryotes and eukaryotes.
Numerical analysis of magnetic nanoparticle transport in microfluidic systems under the influence of permanent magnets
Authors: Cao Quanliang , Han Xiaotao , Li Liang
Published: October 2012

A finite element technique was employed for analysing the transport behaviour of magnetic nanoparticles (MNPs) under the gradient magnetic field generated by rectangular permanent magnets with different configurations. To predict the exact particle dynamic behaviour, the governing non-linear differential equations, Navier–Stokes and convection–diffusion were coupled with the magnetic field equation. The MNP concentration distribution was calculated and taken as an evaluation parameter to show where MNPs are preferentially captured in a microchannel. Since the dynamic behaviour of MNPs in the flow was dependent on the competition between magnetic and fluidic forces, the effects of the flow velocity and magnetic field strength on the MNP concentration distribution were analysed. Meanwhile, the effects of magnetic design parameters for permanent magnets on the magnetic force and MNP concentration distribution were analysed. Results showed that the MNP concentration in the capture region increased with magnetic field strength and decreased with increasing flow velocity. And the shape and position of the high concentration regions were related to the applied inlet velocity, magnetic field strength, geometry of the magnets and the orientation of the remanent flux density. The simulations performed can be used as a tool for the design and optimization of millimetre-sized rectangular magnets for developing efficient lab-on-a-chip systems.
Electrical properties of novel three-phase polymer nanocomposites with a high dielectric constant
Authors: Goyal R K , Kulkarni A B
Published: October 2012

Novel three-phase poly(vinylidene fluoride) (PVDF)/lead zirconate titanate (PZT)/expanded graphite (EG) nanocomposites were prepared using the solution method followed by hot pressing. The loading of PZT powder was varied from 0 to 85 wt% (∼57 vol%) in the PVDF matrix. Scanning electron microscopy revealed uniform dispersion of PZT particles in the matrix. X-ray diffraction showed the presence of α-phase of PVDF in the nanocomposites. Dielectric constant of the 80 wt% (C-80) composites increased to approximately 57 and it was further increased to approximately 192, 237 and 842 for the C-80 nanocomposites containing additional EG content of 0.25 wt%, 0.50 wt% and 0.75 wt%, respectively. However, it decreased with increasing frequency. The electrical conductivity and dissipation factor also increased significantly with increasing content of EG. Various theoretical models were used to rationalize the dielectric behaviour of binary composites.
The Fate of Maleic Hydrazide on Tobacco during Smoking
Authors: Zhang Hongfei , Tang Gangling , Liu Nan , Bian Zhaoyang , Hu Qingyuan
Published: October 2012

Tobacco mainstream smoke (MSS) and sidestream smoke (SSS), butts, and ashes from commercial cigarettes and maleic hydrazide (MH) spiked cigarettes were analyzed for their MH contents. The MH transfer rates obtained for MSS ranged from 1.4% to 3.7%, for SSS ranged from 0.2% to 0.9%, and for butts ranged from 1.1% to 1.9%. And as expected, MH is absent in ashes. The transfer rate of MH into mainstream smoke is the top one during in transfer rate into main-stream, side-stream, ashes, and butts, and higher MH levels lead to more MH in smoke. Further, analysis of total MH in butts and ashes along with that in MSS and SSS indicates that much MH is destructed during the smoking process.
On the structural relations of malachite. II. The brochantite MDO polytypes
Authors: Girgsdies Frank , Behrens Malte
Published: October 2012

The structural relation between malachite and the brochantite MDO (maximum degree of order) polytypes is discussed. It is demonstrated that the same building blocks which form the basis of brochantite polytypism also occur in malachite. The different arrangements of these building blocks in the two mineral structures are rationalized as a result of the different coordination geometries required by the respective non-metal atoms acting as linkers. The compound stoichiometries are discussed in light of a common structured formula scheme, in which pairs of H atoms can play a similar role as single non-H atoms. An overview on the occurrence of malachite-like building blocks in several other crystal structures is given.
Sebaceous‐like clear cell changes in primary lung cancer
Authors: Matsukuma Susumu , Obara Kiyohaya , Kono Takako , Takeo Hiroaki , Sato Kimiya
Published: October 2012

We examined two cases of primary lung cancer with sebaceous‐like clear cells (SLCCs), defined as clear carcinoma cells with microvacuolated cytoplasm and centrally located nuclei, which were selected from among 281 surgical/autopsy cases of lung cancer (2/281, 0.7%). Both cases were higher stage (stage IIA and IIIA), and SLCCs were intermingled with adenocarcinoma cells of usual type. They showed minute mucin staining, no evidence of glycogen, diffuse positivity for epithelial membrane antigen and carcinoembryonic antigen, focal positivity for thyroid transcription factor‐1, and negativity for Napsin A and gross cystic disease fluid protein‐15. Oil red O stain and ultrastructural examination in both cases failed to reveal lipid in SLCCs. SLCCs could represent non‐specific changes of lung adenocarcinoma with a relatively advanced stage, and should be discriminated from true sebaceous differentiation.
A molecular phylogeny of the cosmopolitan hyperdiverse genusHydraenaKugelann (Coleoptera, Hydraenidae)
Authors: TRIZZINO MARCO , JÄCH MANFRED A. , AUDISIO PAOLO , ALONSO ROCIO , RIBERA IGNACIO
Published: October 2012

With almost 900 described species,HydraenaKugelann (Hydraenidae) is one of the largest genera among Coleoptera. The subgeneric classification ofHydraenahas been controversial, with 11 subgeneric names having so far been attributed to it. Some of these,HaenydraRey andSpanglerinaPerkins, have been treated as valid genera, as subgenera or as species groups. The most recent complete treatment of the genus, based on a cladistic analysis of morphological characters, recognized two major lineages, and only these were classified as subgenera:Hydraenopsis(mainly Gondwanan distribution), andHydraenas.str. (mainly Laurasian). Here, we reconstruct the phylogeny ofHydraenausing 212 species plus several outgroups and approximately 4 kb of sequence data from two nuclear (SSUandLSU) and four mitochondrial genes (cox1,rrnL,trnLandnad1). Data were aligned with two different strategies of multiple alignment (implemented inmafftandprank), and the phylogenies reconstructed using maximum likelihood and Bayesian methods. We estimated approximate ages of the main nodes using a relaxed molecular clock with Bayesian methods, and ana priorievolutionary rate of 0.01 substitutions/site/million years (Ma) plus a calibration point based on a biogeographical split. We found strong support for the monophyly ofHydraenaand many of the clades recognized with morphological data. The following clades are considered as subgenera:PhothydraenaKuwert,SpanglerinaPerkins,HolcohydraenaKuwert,HydraenopsisJanssens andHydraenas.str. The placement of three species groups, two Neotropical (H. multispinagroup,H. paeminosagroup) and one South African/Madagascan (H. monikaegroup), is uncertain, and they are consideredincertae sediswithinHydraena. The origin of the genus was estimated to be in the Lower Eocene, with many species complexes diversifying in the Pleistocene. Dispersal events seem to have played a key role in order to determine the current distribution of the species groups in the southern hemisphere (mainly inHydraenopsis).