Fluctuating selection and global change: a synthesis and review on disentangling the roles of climate amplitude, predictability and novelty.

A formidable challenge for global change biologists is to predict how natural populations will respond to the emergence of conditions not observed at present, termed novel climates. Popular approaches to predict population vulnerability are based on the expected degree of novelty relative to the amplitude of historical climate fluctuations experienced by a population. Here, we argue that predictions focused on amplitude may be inaccurate because they ignore the predictability of environmental fluctuations in driving patterns of evolution and responses to climate change. To address this disconnect, we review major findings of evolutionary theory demonstrating the conditions under which phenotypic plasticity is likely to evolve in natural populations, and how plasticity decreases population vulnerability to novel environments. We outline key criteria that experimental studies should aim for to effectively test theoretical predictions, while controlling for the degree of climate novelty. We show that such targeted tests of evolutionary theory are rare, with marine systems being overall underrepresented in this venture despite exhibiting unique opportunities to test theory. We conclude that with more robust experimental designs that manipulate both the amplitude and predictability of fluctuations, while controlling for the degree of novelty, we may better predict population vulnerability to climate change.

NWChem: Past, present, and future.

Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook.

Fast and direct measurements of the electrical properties of graphene using micro four-point probes.

We present measurements of the electronic properties of graphene using a repositionable micro four-point probe system, which we show here to have unique advantages over measurements made on lithographically defined devices; namely speed, simplicity and lack of a need to pattern graphene. Measurements are performed in ambient, vacuum and controlled environmental conditions using an environmental scanning electron microscope (SEM). The results are comparable to previous results for microcleaved graphene on silicon dioxide (SiO(2)). We observe a pronounced hysteresis of the charge neutrality point, dependent on the sweep rate of the gate voltage; and environmental measurements provide insight into the sensor application prospects of graphene. The method offers a fast, local and non-destructive technique for electronic measurements on graphene, which can be positioned freely on a graphene flake.

High cortisol awakening response is associated with an impairment of the effect of bright light therapy.

OBJECTIVE: We investigated the predictive validity of the cortisol awakening response (CAR) in patients with non-seasonal major depression. METHOD: Patients were treated with sertraline in combination with bright or dim light therapy for a 5-week period. Saliva cortisol levels were measured in 63 patients, as an awakening profile, before medication and light therapy started. The CAR was calculated by using three time-points: awakening and 20 and 60 min after awakening. RESULTS: Patients with low CAR had a very substantial effect of bright light therapy compared with dim light therapy, whereas patients with a high CAR had no effect of bright light therapy compared with dim light therapy. CONCLUSION: High CAR was associated with an impairment of the effect of bright light therapy. This result raises the question of whether bright light acts through a mechanism different from that of antidepressants.

Application of adjoint Monte Carlo to accelerate simulations of mono-directional beams in treatment planning for boron neutron capture therapy.

This paper deals with the application of the adjoint transport theory in order to optimize Monte Carlo based radiotherapy treatment planning. The technique is applied to Boron Neutron Capture Therapy where most often mixed beams of neutrons and gammas are involved. In normal forward Monte Carlo simulations the particles start at a source and lose energy as they travel towards the region of interest, i.e., the designated point of detection. Conversely, with adjoint Monte Carlo simulations, the so-called adjoint particles start at the region of interest and gain energy as they travel towards the source where they are detected. In this respect, the particles travel backwards and the real source and real detector become the adjoint detector and adjoint source, respectively. At the adjoint detector, an adjoint function is obtained with which numerically the same result, e.g., dose or flux in the tumor, can be derived as with forward Monte Carlo. In many cases, the adjoint method is more efficient and by that is much quicker when, for example, the response in the tumor or organ at risk for many locations and orientations of the treatment beam around the patient is required. However, a problem occurs when the treatment beam is mono-directional as the probability of detecting adjoint Monte Carlo particles traversing the beam exit (detector plane in adjoint mode) in the negative direction of the incident beam is zero. This problem is addressed here and solved first with the use of next event estimators and second with the application of a Legendre expansion technique of the angular adjoint function. In the first approach, adjoint particles are tracked deterministically through a tube to a (adjoint) point detector far away from the geometric model. The adjoint particles will traverse the disk shaped entrance of this tube (the beam exit in the actual geometry) perpendicularly. This method is slow whenever many events are involved that are not contributing to the point detector, e.g., neutrons in a scattering medium. In the second approach, adjoint particles that traverse an adjoint shaped detector plane are used to estimate the Legendre coefficients for expansion of the angular adjoint function. This provides an estimate of the adjoint function for the direction normal to the detector plane. In a realistic head model, as described in this paper, which is surrounded by 1020 mono-directional neutron/gamma beams and from which the best ones are to be selected, the example calculates the neutron and gamma fluxes in ten tumors and ten organs at risk. For small diameter beams (5 cm), and with comparable relative errors, forward Monte Carlo is seen to be 1.5 times faster than the adjoint Monte Carlo techniques. For larger diameter neutron beams (10 and 15 cm), the Legendre technique is found to be 6 and 20 times faster, respectively. In the case of gammas alone, for the 10 and 15 cm diam beams, both adjoint Monte Carlo Legendre and point detector techniques are respectively 2 and 3 times faster than forward Monte Carlo.

DNA-binding domain of human c-Myc produced in Escherichia coli.

We have identified the domain of the human c-myc protein (c-Myc) produced in Escherichia coli that is responsible for the ability of the protein to bind sequence-nonspecific DNA. Using analysis of binding of DNA by proteins transferred to nitrocellulose, DNA-cellulose chromatography, and a nitrocellulose filter binding assay, we examined the binding properties of c-Myc peptides generated by cyanogen bromide cleavage, of mutant c-Myc, and of proteins that fuse portions of c-Myc to staphylococcal protein A. The results of these analyses indicated that c-Myc amino acids 265 to 318 were responsible for DNA binding and that other regions of the protein (including a highly conserved basic region and a region containing the leucine zipper motif) were not required. Some mutant c-Mycs that did not bind DNA maintained rat embryo cell-cotransforming activity, which indicated that the c-Myc property of in vitro DNA binding was not essential for this activity. These mutants, however, were unable to transform established rat fibroblasts (Rat-1a cells) that were susceptible to transformation by wild-type c-Myc, although this lack of activity may not have been due to their inability to bind DNA.

Transcription factor ATF2 cooperates with v-Jun to promote growth factor-independent proliferation in vitro and tumor formation in vivo.

ATF2 belongs to the bZIP family of transcription factors and controls gene expression via 8-bp ATF/CREB motifs either as a homodimer or as a heterodimer-for instance, with Jun-but has never been shown to be directly involved in oncogenesis. Experiments were designed to evaluate a possible role of ATF2 in oncogenesis in chick embryo fibroblasts (CEFs) in the presence or absence of v-Jun. We found that (i) forced expression of ATF2 cannot alone cause transformation, (ii) overexpression of ATF2 plus v-Jun specifically stimulates v-Jun-induced growth in medium with a reduced amount of serum, and (iii) the efficiency of low-serum growth correlates with the activity of a Jun-ATF2-dependent model promoter in stably transformed CEFs. Analysis of ATF2 and Jun dimerization mutants showed that the growth-stimulatory effect of ATF2 is likely to be mediated by v-Jun-ATF2 heterodimers since (i) v-Jun-m1, a mutant with enhanced affinity for ATF2, induces growth in low-serum medium much more efficiently than v-Jun, when expressed alone or in combination with ATF2; and (ii) ATF2/fos, a mutant that efficiently binds to v-Jun but is unable to form stable homodimers, shows enhanced oncogenic cooperation with v-Jun. In addition, we examined the role of ATF2 in tumor formation by subcutaneous injection of CEFs into chickens. In contrast to v-Jun, v-Jun-m1 gave rise to numerous fibrosarcomas while coexpression of ATF2 and v-Jun-m1 led to a dramatic development of fibrosarcomas visible within 1 week. Together these data demonstrate that overexpressed ATF2 potentiates the ability of v-Jun-transformed CEFs to grow in low-serum medium in vitro and contributes to the formation of tumors in vivo.

Ras-dependent regulation of c-Jun phosphorylation is mediated by the Ral guanine nucleotide exchange factor-Ral pathway.

The transcription factor c-Jun is critically involved in the regulation of proliferation and differentiation as well as cellular transformation induced by oncogenic Ras. The signal transduction pathways that couple Ras activation to c-Jun phosphorylation are still partially elusive. Here we show that an activated version of the Ras effector Rlf, a guanine nucleotide exchange factor (GEF) of the small GTPase Ral, can induce the phosphorylation of serines 63 and 73 of c-Jun. In addition, we show that growth factor-induced, Ras-mediated phosphorylation of c-Jun is abolished by inhibitory mutants of the RalGEF-Ral pathway. These results suggest that the RalGEF-Ral pathway plays a major role in Ras-dependent c-Jun phosphorylation. Ral-dependent regulation of c-Jun phosphorylation includes JNK, a still elusive JNKK, and possibly Src.

Differential effects of the adenovirus E1A oncogene on members of the AP-1 transcription factor family.

The adenovirus early region 1A (E1A) oncogene interferes with the expression level and activity of the AP-1 transcription factor family. E1A abolished the transactivating function of AP-1 (Jun/Fos), which binds to the 12-O-tetradecanoylphorbol-13-acetate-responsive element of the collagenase gene (collTRE). In contrast, the activity of another member of the AP-1 family that binds to the c-junTRE was not repressed. The mRNA expression of the c-jun gene was, in fact, strongly elevated in various cell types expressing the E1A gene of either adenovirus type 5 (Ad5) or Ad12. The regulation of the junB gene by adenovirus E1A, on the other hand, depended both on the cell type and on the transforming adenovirus serotype. The fact that E1A-induced alterations in the repertoire of AP-1 transcription factors depend on its transforming domain in conserved region 1 suggests that the effects are relevant for the transformation process.

Design of a rotating facility for extracorporal treatment of an explanted liver with disseminated metastases by boron neutron capture therapy with an epithermal neutron beam.

In 2001, at the TRIGA reactor of the University of Pavia (Italy), a patient suffering from diffuse liver metastases from an adenocarcinoma of the sigmoid was successfully treated by boron neutron capture therapy (BNCT). The procedure involved boron infusion prior to hepatectomy, irradiation of the explanted liver at the thermal column of the reactor, and subsequent reimplantation. A complete response was observed. This encouraging outcome stimulated the Essen/Petten BNCT group to investigate whether such an extracorporal irradiation could be performed at the BNCT irradiation facility at the HFR Petten (The Netherlands), which has very different irradiation characteristics than the Pavia facility. A computational study has been carried out. A rotating PMMA container with a liver, surrounded by PMMA and graphite, is simulated using the Monte Carlo code MCNP. Due to the rotation and neutron moderation of the PMMA container, the initial epithermal neutron beam provides a nearly homogeneous thermal neutron field in the liver. The main conditions for treatment as reported from the Pavia experiment, i.e. a thermal neutron fluence of 4 x 10(12) +/- 20% cm(-2), can be closely met at the HFR in an acceptable time, which, depending on the defined conditions, is between 140 and 180 min.

Distinct roles of Jun : Fos and Jun : ATF dimers in oncogenesis.

Jun : Fos and Jun : ATF complexes represent two classes of AP-1 dimers that (1) preferentially bind to either heptameric or octameric AP-1 binding sites, and (2) are differently regulated by cellular signaling pathways and oncogene products. To discriminate between the functions of Jun : Fos, Jun : ATF and Jun : Jun, mutants were developed that restrict the ability of Jun to dimerize either to itself, or to Fos(-like) or ATF(-like) partners. Introduction of these mutants in chicken embryo fibroblasts shows that Jun : Fra2 and Jun : ATF2 dimers play distinct, complementary roles in in vitro oncogenesis by inducing either anchorage independence or growth factor independence, respectively. v-Jun : ATF2 rather than v-Jun : Fra2 triggers the development of primary fibrosarcomas in the chicken wing. Genes encoding extracellular matrix components seem to constitute an important subset of v-Jun : ATF2-target genes. Repression of the matrix component SPARC by Jun is essential for the induction of fibrosarcomas. Avian primary cells transformed by either Jun : Fra2 or Jun : ATF2 thus provide powerful tools for the investigation of the downstream pathways involved in oncogenesis. Further genetic studies with Jun dimerization mutants will be required to be precise and extend the specific roles of the Jun : Fos and Jun : ATF dimers during cancer progression in avian and mammalian systems.

Transcription factor ATF3 partially transforms chick embryo fibroblasts by promoting growth factor-independent proliferation.

Activating Transcription Factor 3 (ATF3) is a member of the bZip family of transcription factors. Previous studies in mammalian cells suggested that like other bZip family members e.g. Jun and Fos, ATF3 might play a role in the control of cell proliferation and participate in oncogenic transformation. To investigate this putative ATF3 function directly, the rat ATF3 protein was compared with v-Jun for its ability to transform primary cultures of chick embryo fibroblasts (CEFs). Like CEFs accumulating v-Jun, CEFs accumulating the ATF3 protein displayed a typical, fusiform morphology, associated with an enhanced capacity to grow in medium with reduced amount of serum. However, in contrast to v-Jun-transformed CEFs, the ATF3 overexpressing cells could not promote colony formation from single cells in agar. Partial transformation induced by ATF3 was found to be associated with repression of multiple cellular genes that are also down-regulated by v-Jun, including those coding for the extracellular components fibronectin, decorin, thrombospondin 2, and the pro-apoptotic protein Par-4. These data demonstrate that, at least in primary avian cells, rat ATF3 possesses an intrinsic oncogenic potential. Moreover, the results suggest that ATF3 might induce growth factor independence by down-regulating a subset of the genes repressed by v-Jun.

Increased cyclin A and decreased cyclin D levels in adenovirus 5 E1A-transformed rodent cell lines.

Adenovirus-(Ad)- E1A proteins carry two conserved domains (CR1 and CR2) required for transformation of primary rodent cells and essential for association with cellular proteins, including p105RB, p58cyclin A and p33cdk2. We show that in normal rat kidney 49F (NRK) cell lines expressing various mutant Ad5-E1A genes, CR2-, but not CR-1-, deletion mutants induce a typical transformed phenotype as characterized by morphology, absence of density arrest and loss of serum requirement. This indicates that induction of these transformed properties is a function of CR1. The fact that E1A proteins with deletions in CR2 show a greatly reduced association with RB, cyclin A and p33cdk2 suggests that these associations are dispensable for E1A-mediated transformation of NRK cells. Induction of the transformed properties is accompanied by a CR1-dependent increase in Proliferating Cell Nuclear Antigen and cyclin A gene expression. Elevated mRNA and protein levels of cyclin A were also found in Ad12-E1-transformed NRK cells but not in ras-transformed NRK cells. On the other hand, cyclin D expression is decreased in a CR1-dependent manner. Although Ad5-E1A proteins are sufficient to transform NRK cells, further deregulation of growth is obtained when Ad5-E1B proteins are co-expressed. One of the Ad5-E1B effects is the sequestration of the p53 protein into a cytoplasmic body containing the p53/Ad5-E1B-55 kD complex. Interestingly, in NRK cell lines expressing Ad5-E1B-55 kD, cyclin A could be detected not only in the nucleus but also in the cytoplasmic bodies. These results indicate that the deregulation of cell cycle control by the Adenovirus-E1 region may be due to a CR1-dependent alteration of the expression of cyclins A and D.

Co-regulated expression of junB and MHC class I genes in adenovirus-transformed cells.

The expression of the junB gene parallels the expression of the MHC class I genes in Adenovirus (Ad) transformed cells. In Ad12E1-transformed primary BRK cells both genes are transcriptionally repressed only when the 13S product of Ad12E1A is present. This indicates that repression of MHC class I and junB genes is a function of conserved region 3 (CR3) of the Ad12E1A protein. In Ad5-transformed BRK cells expression of these genes is unchanged. In established NRK cells, however, introduction of Ad12E1A does not cause repression of the MHC class I and junB genes, but in these cells Ad5E1A increases the expression of both MHC class I and junB. Using mutant Ad5E1A genes, it is shown that this activation is mediated by CR1. Introduction of a functional junB gene under the control of a heterologous promoter in Ad12E1-transformed BRK cells causes no increase in MHC class I expression. This demonstrates that the down-regulation of junB is not directly responsible for class I repression, but rather that both genes are coregulated by the Ad12E1 region.

The repression of the growth factor-inducible genes JE, c-myc and stromelysin by adenovirus E1A is mediated by conserved region 1.

The growth factor-inducible cellular genes JE, c-myc and stromelysin (sml) are strongly repressed upon transformation by adenovirus E1A. As E1A proteins are multifunctional and apparently contain distinct domains (conserved regions 1, 2 and 3), each with a specific effect on gene regulation and cell-transformation, we have investigated which of the three conserved regions are responsible for the reduced expression of these genes. To this end, we monitored the expression of the JE, sml and c-myc genes in a panel of normal rat kidney (NRK) cells expressing different mutant E1A genes. Only CR1, and not CR2 or CR3 were found to be essential for the repression of the genes, indicating that CR1, one of the regions essential for cell transformation, represents an autonomous gene regulatory function that can operate in the absence of CR2. We also show that the association of E1A proteins to a 300 kD cellular protein in NRK cells coincides with the ability to repress these genes.

The N-terminal transactivation domain of ATF2 is a target for the co-operative activation of the c-jun promoter by p300 and 12S E1A.

The adenovirus E1A proteins activate the c-jun promoter through two Jun/ATF-binding sites, jun1 and jun2. P300, a transcriptional coactivator of several AP1 and ATF transcription factors has been postulated to play a role in this activation. Here, we present evidence that p300 can control c-jun transcription by acting as a cofactor for ATF2: (1) Over-expression of p300 was found to stimulate c-jun transcription both in the presence and absence of E1A. (2) Like E1A, p300 activates the c-jun promoter through the junl and jun2 elements and preferentially activates the N-terminal domain of ATF2. (3) Co-immunoprecipitation assays of crude cell extracts indicate that endogenous p300/CBP(-like) proteins and ATF2 proteins are present in a multiprotein complex that can bind specifically to the jun2 element. We further demonstrate that the Stress-Activated-Protein-Kinase (SAPK) target sites of ATF2, Thr69 and Thr71 are not required for the formation of the p300/CBP-ATF2 multiprotein complex. These data indicate that E1A does not inhibit all transcription activation functions of p300, and, in fact, cooperates with p300 in the activation of the ATF2 N-terminus.

Gelina neutron target optimisation.

A study is being performed on the properties of the Geel Electron Linear Accelerator (GELINA), a powerful white neutron source, designed for the high-energy resolution time-of-flight measurements. The main aim of this study is to reduce the time spread of neutrons of the given energy without compromising the neutron yield. Both time spread and neutron intensity influence the experimental accuracy of high-resolution neutron cross section measurements, which are particularly important in the resonance region. The quantities of interest have been simulated with coupled electron-photon-neutron steady state and transient MCNP4C3 calculations. Following benchmarking of the code to the properties of the existing target, neutron yield, energy spectra, resolution functions, and neutron and heat spatial distributions have been determined for various alternative geometries and materials. At a fixed accelerator power, actinides deliver the highest neutron yield and a small target provides the best time resolution. The resulting high-power density requires a joint optimisation of the thermal hydraulics and neutronics properties.

Improving organic tandem solar cells based on water-processed nanoparticles by quantitative 3D nanoimaging.

Organic solar cells have great potential for upscaling due to roll-to-roll processing and a low energy payback time, making them an attractive sustainable energy source for the future. Active layers coated with water-dispersible Landfester particles enable greater control of the layer formation and easier access to the printing industry, which has reduced the use of organic solvents since the 1980s. Through ptychographic X-ray computed tomography (PXCT), we image quantitatively a roll-to-roll coated photovoltaic tandem stack consisting of one bulk heterojunction active layer and one Landfester particle active layer. We extract the layered morphology with structural and density information including the porosity present in the various layers and the silver electrode with high resolution in 3D. The Landfester particle layer is found to have an undesired morphology with negatively correlated top- and bottom interfaces, wide thickness distribution and only partial surface coverage causing electric short circuits through the layer. By top coating a polymer material onto the Landfester nanoparticles we eliminate the structural defects of the layer such as porosity and roughness, and achieve the increased performance larger than 1 V expected for a tandem cell. This study highlights that quantitative imaging of weakly scattering stacked layers of organic materials has become feasible by PXCT, and that this information cannot be obtained by other methods. In the present study, this technique specifically reveals the need to improve the coatability and layer formation of Landfester nanoparticles, thus allowing improved solar cells to be produced.

Ultraviolet photoelectron spectroscopy of cyclic amidines. 2. Electronic structure of clonidine and some related 2-(phenylimino)imidazolidines with alpha-adrenergic activity.

Ultraviolet photoelectron spectroscopy (UV PES) and CNDO/s molecular orbital calculations have been employed to investigate the electronic structure of clonidine and some other 2-(phenylimino)imidazolidines. The assignment of the bands in the spectra to particular molecular orbitals is based on the CNDO/s results in conjunction with Koopmans' theorem, substituent effects, and differences in intensity between the He (I) and He(II) spectra. The location of the energy levels of orbitals with mainly nN and delta character is not correctly estimated estimated by CNDO/s, while the pi orbital energy levels are satisfactorally predicted. The UV PES and CNDO/s results indicate in contrast investigated 2-(phenylimino)imidazolidines, which may indicate that differences in hypotensive activity cannot be ascribed to variations in steric hindrance within the molecules. The first ionization energies of the pharmacologically active 20-(phenylimino)imidazolidines do not correlate with hypotensive activity based on dosage data after intravenous administration to rats.

Tyrosine hydroxylase polymorphism and phenotypic heterogeneity in bipolar affective disorder: a multicenter association study.

Tyrosine hydroxylase (TH), the rate-limiting enzyme in the metabolism of catecholamines, is considered a candidate gene in bipolar affective disorder (BPAD) and has been the subject of numerous linkage and association studies. Taken together, most results do not support a major gene effect for the TH gene in BPAD. Genetic and phenotypic heterogeneity may partially explain the difficulty of confirming the exact role of this gene using both association and linkage methods. Four hundred one BPAD patients and 401 unrelated matched controls were recruited within a European collaborative project (BIOMED1 project in the area of brain research, European Community grant number CT 92-1217, project leader: J. Mendlewicz) involving 14 centers for a case-control association study with a tetranucleotide polymorphism in the TH gene. Patients and controls were carefully matched for geographical origin. Phenotypic heterogeneity was considered and subgroup analyses were performed with relevant variables: age at onset, family history, and diagnostic stability. No association was observed in the total sample or for subgroups according to age at onset (n = 172), family history alone (n = 159), or high degree of diagnostic stability and a positive family history (n = 131). The results of this association study do not confirm the possible implication of TH polymorphism in the susceptibility to BPAD.