Search for Dark Photons with Superconducting Radio Frequency Cavities.

We conduct the first "light-shining-through-wall" (LSW) search for dark photons using two state-of-the-art high-quality-factor superconducting radio frequency (SRF) cavities -Dark SRF-and report the results of its pathfinder run. Our new experimental setup enables improvements in sensitivity over previous searches and covers new dark photon parameter space. We design delicate calibration and measurement protocols to utilize the high-Q setup at Dark SRF. Using cavities operating at 1.3 GHz, we establish a new exclusion limit for kinetic mixing as small as ε=1.6×10^{-9} and provide the world's best constraints on dark photons in the 2.1×10^{-7}-5.7×10^{-6} eV mass range. Our result is the first proof of concept for the enabling role of SRF cavities in LSW setups, with ample opportunities for further improvements. In addition, our data set a competitive lab-based limit on the standard model photon mass by searching for longitudinal photon polarization.

Retrospective comparison between MRI examinations during radiographer-administered intranasal sedation or general anesthesia.

INTRODUCTION: In order for young children to be able to undergo a Magnetic Resonance Imaging (MRI) examination, general anesthesia is often required. The aim of this study was to compare the image quality, times, and costs of the examinations of infant brains performed with MRI either during sedation with dexmedetomidine administered by radiographers or anesthesia with propofol administered by anesthesia staff. METHODS: This study was a quantitative retrospective study of 27 consecutive standard brain examinations performed under sedation or anesthesia, involving 15 children under sedation and 12 under anesthesia. The age of the children was from 0.5 to five years old. The image quality was evaluated by three radiologists experienced in pediatric MRI examinations. Information such as examination time and the expense of the examination was also collected. RESULTS: There was no statistically significant difference in the general image quality, but one image series was assessed to have significantly better image quality under sedation than under anesthesia, but all images had very high quality. However, it emerged that children under anesthesia were at the hospital on average 55 min longer and the scanner room was occupied 20 min longer on average. The anesthesia examinations were three times more expensive. CONCLUSION: This study demonstrated equivalent image quality between sedation and anesthesia. In addition, sedation was less time-consuming and had a lower price, partly because no extra anesthetic staff were required. The use of intranasal sedation offers a possibility to expand the competence area for radiographers. IMPLICATIONS FOR PRACTICE: If radiographers learn to perform intranasal sedation, examinations can be performed in less time, at a third of the staff costs while maintaining image quality.

Psychometric evaluation of the electronic faces thermometer scale for pain assessment in children 8-17 years old: A study protocol.

It is often a challenge for a child to communicate their pain, and their possibilities to do so should be strengthened in healthcare settings. Digital self-assessment provides a potential solution for person-centered care in pain management and promotes child participation when a child is ill. A child's perception of pain assessment differs when it is assessed using digital or analog formats. As we move into the digital era, there is an urgent need to validate digital pain assessment tools, including the newly developed electronic Faces Thermometer Scale (eFTS). This study protocol describes three studies with the overall aim to evaluate psychometric properties of the eFTS for assessing pain in children 8-17 years of age. A multi-site project design combining quantitative and qualitative methods will be used for three observational studies. Study 1: 100 Swedish-speaking children will report the level of anticipated pain from vignettes describing painful situations in four levels of pain and a think-aloud method will be used for data collection. Data will be analyzed with phenomenography as well as descriptive and comparative statistics. Study 2: 600 children aged 8-17 years at pediatric and dental settings in Sweden, Denmark, Iceland, and USA will be included. Children will assess their pain intensity due to medical or dental procedures, surgery, or acute pain using three different pain Scales for each time point; the eFTS, the Faces Pain Scale Revised, and the Coloured Analogue Scale. Descriptive and comparative statistics will be used, with subanalysis taking cultural context into consideration. Study 3: A subgroup of 20 children out of these 600 children will be purposely included in an interview to describe experiences of grading their own pain using the eFTS. Qualitative data will be analyzed with content analysis. Our pilot studies showed high level of adherence to the study procedure and rendered only a small revision of background questionnaires. Preliminary analysis indicated that the instruments are adequate to be used by children and that the analysis plan is feasible. A digital pain assessment tool contributes to an increase in pain assessment in pediatric care. The Medical Research Council framework for complex interventions in healthcare supports a thorough development of a new scale. By evaluating psychometric properties in several settings by both qualitative and quantitative methods, the eFTS will become a well-validated tool to strengthen the child's voice within healthcare.

Transcription of the mouse dihydrofolate reductase gene proceeds unabated through seven polyadenylation sites and terminates near a region of repeated DNA.

We observed equimolar transcription throughout the 35-kilobase mouse dihydrofolate reductase structural gene. Transcription termination occurred within a discrete region (900 base pairs) located 1 kilobase beyond the last of seven functional polyadenylation sites and near a repetitive DNA sequence element. The results imply that a distinct genetic signal may be associated with the process of transcription termination.

Control of cellular gene expression during adenovirus infection: induction and shut-off of dihydrofolate reductase gene expression by adenovirus type 2.

Infection of human cells by adenovirus results in multiple alterations of host gene expression. To examine the effects of viral infection on the expression of a single gene, a line of human cells was developed which is resistant to growth in methotrexate and which contains amplified RNA and protein specific for dihydrofolate reductase (DHFR). Cytogenetic evidence indicated the presence of amplified DNA. Adenovirus infection of these cells caused an induction and subsequent decline in the synthesis of DHFR protein. The maximum DHFR induction occurred 16 to 19 h after infection and reached a level 2.5-fold greater than that observed in uninfected cells. Induction of DHFR protein synthesis was accompanied by concomitant increases in the level of steady-state DHFR-specific cytoplasmic RNA. The relative rate of DHFR mRNA production (i.e., the appearance of DHFR-specific mRNA sequences in the cytoplasm) also increased 2.5-fold during induction. Later in infection, the relative rate of DHFR protein synthesis declined, reaching a level below that observed in uninfected cells. This decline was accompanied by a similar decline in the steady-state levels of DHFR RNA and in the relative rate of synthesis of DHFR mRNA. These data suggest that adenovirus infection controls DHFR gene expression by increasing and subsequently decreasing the relative rate at which DHFR-specific mRNA sequences appear in the cytoplasm and enter the pool of mRNA available for translation.

Engineering serendipity: High-throughput discovery of materials that resist bacterial attachment.

Controlling the colonisation of materials by microorganisms is important in a wide range of industries and clinical settings. To date, the underlying mechanisms that govern the interactions of bacteria with material surfaces remain poorly understood, limiting the ab initio design and engineering of biomaterials to control bacterial attachment. Combinatorial approaches involving high-throughput screening have emerged as key tools for identifying materials to control bacterial attachment. The hundreds of different materials assessed using these methods can be carried out with the aid of computational modelling. This approach can develop an understanding of the rules used to predict bacterial attachment to surfaces of non-toxic synthetic materials. Here we outline our view on the state of this field and the challenges and opportunities in this area for the coming years. STATEMENT OF SIGNIFICANCE: This opinion article on high throughput screening methods reflects one aspect of how the field of biomaterials research has developed and progressed. The piece takes the reader through key developments in biomaterials discovery, particularly focusing on need to reduce bacterial colonisation of surfaces. Such bacterial resistant surfaces are increasingly required in this age of antibiotic resistance. The influence and origin of high-throughput methods are discussed with insights into the future of biomaterials development where computational methods may drive materials development into new fertile areas of discovery. New biomaterials will exhibit responsiveness to adapt to the biological environment and promote better integration and reduced rejection or infection.

Job demand and control interventions: a stakeholder-centered best-evidence synthesis of systematic reviews on workplace disability.

BACKGROUND: Physical and psychological job demands in combination with the degree of control a worker has over task completion, play an important role in reducing stress. Occupational stress is an important, modifiable factor affecting work disability. However, the effectiveness of reducing job demands or increasing job control remains unclear, particularly for outcomes of interest to employers, such as absenteeism or productivity. OBJECTIVE: This systematic review reports on job demand and control interventions that impact absenteeism, productivity and financial outcomes. METHODS: A stakeholder-centered best-evidence synthesis was conducted with researcher and stakeholder collaboration throughout. Databases and grey literature were searched for systematic reviews between 2000 and 2012: Medline, EMBASE, the Cochrane Database of Systematic Reviews, DARE, CINAHL, PsycINFO, TRIP, health-evidence.ca, Rehab+, National Rehabilitation Information Center (NARIC), and Institute for Work and Health. Articles were assessed independently by two researchers for inclusion criteria and methodological quality. Differences were resolved through consensus. RESULTS: The search resulted in 3363 unique titles. After review of abstracts, 115 articles were retained for full-text review. 11 articles finally met the inclusion criteria and are summarized in this synthesis. The best level of evidence we found indicates that multimodal job demand reductions for either at-work or off-work workers will reduce disability-related absenteeism. CONCLUSION: In general, the impacts of interventions that aim to reduce job demands or increase job control can be positive for the organization in terms of reducing absenteeism, increasing productivity and cost-effectiveness. However, more high quality research is needed to further assess the relationships and quantify effect sizes for the interventions and outcomes reviewed in this study.

The fitness effects of spontaneous mutations in Caenorhabditis elegans.

Spontaneous mutation to mildly deleterious alleles has emerged as a potentially unifying component of a variety of observations in evolutionary genetics and molecular evolution. However, the biological significance of hypotheses based on mildly deleterious mutation depends critically on the rate at which new mutations arise and on their average effects. A long-term mutation-accumulation experiment with replicate lines of the nematode Caenorhabditis elegans maintained by single-progeny descent indicates that recurrent spontaneous mutation causes approximately 0.1% decline in fitness per generation, which is about an order of magnitude less than that suggested by previous studies with Drosophila. Two rather different approaches, Bateman-Mukai and maximum likelihood, suggest that this observation, along with the observed rate of increase in the variance of fitness among lines, is consistent with a genomic deleterious mutation rate for fitness of approximately 0.03 per generation and with an average homozygous effect of approximately 12%. The distribution of mutational effects for fitness appears to have a relatively low coefficient of variation, being no more extreme than expected for a negative exponential, and for one composite fitness measure (total progeny production) approaches constancy of effects. These results are derived from assays in a benign environment. At stressful temperatures, estimates of the genomic deleterious mutation rate (for genes expressed at such temperatures) is sixfold lower, whereas those for the average homozygous effect is approximately eightfold higher. Our results are reasonably compatible with existing estimates for flies, when one considers the differences between these species in the number of germ-line cell divisions per generation and the magnitude of transposable element activity.

Copper toxicity: evidence for the conversion of cupric to cuprous copper in vivo under anaerobic conditions.

We have determined the toxicity to cells of Escherichia coli B of cupric copper applied under aerobic and anaerobic conditions in two ways. The growth of cells in liquid medium incorporating cupric copper shows differential inhibition, comparing aerobic and anaerobic conditions--toxicity being greater under anoxia. The growth of colonies upon agar plates incorporating cupric copper does not show such a differential effect. We conclude that colonies on plates are largely anoxic even when incubated aerobically. EPR spectra of cells obtained at various times after application of cupric copper under anoxic conditions indicate the conversion of a considerable proportion of the Cu(II) to a non-paramagnetic species, probably Cu(I). We demonstrate that Cu(I) is more toxic than Cu(II) to cells when applied under anoxic conditions and conclude that the difference in toxicity of Cu(II) applied to cells under aerobic and anaerobic conditions results from the greater extent of reduction of Cu(II) to Cu(I) under anaerobic conditions.

Patterned and switchable surfaces for biomolecular manipulation.

The interactions of biomolecules and cells with solid interfaces play a pivotal role in a range of biomedical applications and have therefore been studied in great detail. An improved understanding of these interactions results in the ability to manipulate DNA, proteins and other biomolecules, as well as cells, spatially and temporally at surfaces with high precision. This in turn engenders the development of advanced devices, such as biosensors, bioelectronic components, smart biomaterials and microarrays. Spatial control can be achieved by the production of patterned surface chemistries using modern high-resolution patterning technologies based on lithography, microprinting or microfluidics, whilst temporal control is accessible through the application of switchable surface architectures. The combination of these two surface properties offers unprecedented control over the behaviour of biomolecules and cells at the solid-liquid interface. This review discusses the behaviour of biomolecules and cells at solid interfaces and highlights fundamental and applied research exploring patterned and switchable surfaces.

Solitonlike Stokes pulses in stimulated Raman scattering.

An analytical solution for compressed solitonlike Stokes pulses created by Raman amplification is presented in the limit where the relative velocity between a wide pump pulse and the Stokes pulse is large and pump-depletion effects can be neglected. The concomitant deviations from the classical soliton shape are shown to be harmless for optical communication purposes. In the opposite limit, where pump depletion becomes important, cross-phase modulation between the pump and the Stokes pulse destroys the conditions for compression during Raman amplification.

Localization and sequence analysis of poly(A) sites generating multiple dihydrofolate reductase mRNAs.

The murine dihydrofolate reductase (DHFR) gene gives rise to multiple polyadenylated mRNAs displaying heterogeneity in the length of the 3' untranslated region. These species are present in the cytoplasm at levels that vary over 2 orders of magnitude, suggesting that certain poly(A) sites are preferred over others. Previous observations have shown that three out of the four major sites of polyadenylation do not display consensus hexanucleotide (AATAAA, ATTAAA) signals. We have further analyzed the sequences involved in directing multiple polyadenylation events on the DHFR gene by focusing our attention on the 4.1- and 5.6-kilobase mRNAs, the lowest abundance DHFR species observed on RNA blot analysis. Identification and sequence analysis of the poly(A) addition sites corresponding to these species revealed appropriately positioned consensus hexanucleotide signals; additional nearby poly(A) sites were also detected which apparently do not use consensus hexanucleotides to direct poly(A) addition to DHFR mRNAs of relatively lower abundance. We have also identified polyadenylation sites downstream of the 4.1- and 5.6-kilobase sites which display consensus hexanucleotide signals and correspond to messenger species too rare for detection by routine RNA blot analysis. Our data bring to 11 the number of known functional poly(A) addition sites associated with the DHFR gene.

Binding of heparan sulfate to type V collagen. A mechanism of cell-substrate adhesion.

The functions and molecular interactions of type V collagen in the pericellular matrix are unclear. Our studies show that type V collagen adsorbed on a surface binds heparin/heparan sulfate with apparent higher affinity than do collagen types I, II, III, IV, or VI, fibronectin, or laminin. Therefore, heparin-like molecules may mediate interactions between cells and type V collagen. Hence, type V collagen may act as an anchor for proteoglycans in the extracellular matrix and function as a substrate for glycosaminoglycan-mediated cell attachment. This model is supported by studies showing that Chinese hamster ovary (CHO) cell mutants which are deficient in glycosaminoglycan synthesis attach poorly to type V collagen substrates compared to wild-type cells, whereas attachment of CHO cell mutants to fibronectin substrates is not affected. Also, exogenous heparin reduces attachment of CHO, endothelial, and smooth muscle cells to type V collagen but does not affect cell attachment to fibronectin. The inhibitory activity of the exogenous heparin/heparan sulfate depends on the size and sulfate content of the polysaccharide chains. At tested concentrations, chondroitin sulfate does not affect the attachment of CHO cells or the binding of biotin-conjugated heparan sulfate to wells coated with type V collagen. These data suggest that a certain degree of structural specificity is involved in glycosaminoglycan binding to type V collagen.

Esophageal stricture after cytomegalovirus ulcer treated with ganciclovir.

A 49-year-old man with the acquired immune deficiency syndrome (AIDS) developed epigastric pain, nausea, vomiting, and gastrointestinal bleeding secondary to a cytomegalovirus (CMV)-induced ulceration in the distal esophagus and proximal stomach. All symptoms improved on treatment with ganciclovir. However, 1 month later severe dysphagia led to discovery of a fibrous stricture in the area of the healed ulcer. The dysphagia was controlled by esophageal dilation. Ulcerative lesions caused by CMV can heal with ganciclovir treatment but, as with other esophageal ulcers, healing may be associated with fibrosis and stricture.

Trench-shaped binding sites promote multiple classes of interactions between collagen and the adherence receptors, alpha(1)beta(1) integrin and Staphylococcus aureus cna MSCRAMM.

Most mammalian cells and some pathogenic bacteria are capable of adhering to collagenous substrates in processes mediated by specific cell surface adherence molecules. Crystal structures of collagen-binding regions of the human integrin alpha(2)beta(1) and a Staphylococcus aureus adhesin reveal a "trench" on the surface of both of these proteins. This trench can accommodate a collagen triple-helical structure and presumably represents the ligand-binding site (Emsley, J., King, S. L., Bergelson, J. M., and Liddington, R. C. (1997) J. Biol. Chem. 272, 28512-28517; Symersky, J., Patti, J. M., Carson, M., House-Pompeo, K., Teale, M., Moore, D., Jin, L., Schneider, A., DeLucas, L. J., Höök, M., and Narayana, S. V. L. (1997) Nat. Struct. Biol. 4, 833-838). We report here the crystal structure of the alpha subunit I domain from the alpha(1)beta(1) integrin. This collagen-binding protein also contains a trench on one face in which the collagen triple helix may be docked. Furthermore, we compare the collagen-binding mechanisms of the human alpha(1) integrin I domain and the A domain from the S. aureus collagen adhesin, Cna. Although the S. aureus and human proteins have unrelated amino acid sequences, secondary structure composition, and cation requirements for effective ligand binding, both proteins bind at multiple sites within one collagen molecule, with the sites in collagen varying in their affinity for the adherence molecule. We propose that (i) these evolutionarily dissimilar adherence proteins recognize collagen via similar mechanisms, (ii) the multisite, multiclass protein/ligand interactions observed in these two systems result from a binding-site trench, and (iii) this unusual binding mechanism may be thematic for proteins binding extended, rigid ligands that contain repeating structural motifs.

Amplification and molecular cloning of murine adenosine deaminase gene sequences.

A previously isolated mouse Cl-1D derived cell line (B-1/25) overproduces adenosine deaminase (EC 3.5.4.4) by 3200-fold. The present studies were undertaken to determine the molecular basis of this phenomenon. Rabbit reticulocyte lysate and Xenopus oocyte translation studies indicated that the B-1/25 cells also overproduced adenosine deaminase mRNA. Total poly(A+) RNA derived from B-1/25 was used to construct a cDNA library. After prehybridization with excess parental Cl-1D RNA to selectively prehybridize nonamplified sequences, 32P-labeled cDNA probe synthesized from B-1/25 total poly(A+) RNA was used to identify recombinant colonies containing amplified mRNA sequences. Positive clones containing adenosine deaminase gene sequences were identified by blot hybridization analysis and hybridization-selected translation in both rabbit reticulocyte lysate and Xenopus oocyte translation systems. Adenosine deaminase cDNA clones hybridized with three poly(A+) RNA species of 1.5, 1.7, and 5.2 kilobases in length, all of which were overproduced in the B-1/25 cell line. Dot blot hybridization analysis using an adenosine deaminase cDNA clone showed that the elevated adenosine deaminase level in the B-1/25 cells was fully accounted for by an increase in adenosine deaminase gene copy number. The adenosine deaminase cDNA probes and the cell lines with amplified adenosine deaminase genes should prove extremely useful in studying the structure and regulation of the adenosine deaminase gene.

Multiple binding sites in collagen type I for the integrins alpha1beta1 and alpha2beta1.

Integrins alpha(1)beta(1) and alpha(2)beta(1) are two major collagen receptors on the surface of eukaryotic cells. Binding to collagen is primarily due to an A-domain near the N terminus of the alpha chains. Previously, we reported that recombinant A-domain of alpha(1)beta(1) (alpha(1)A) had at least two affinity classes of binding sites in type I collagen (Rich, R. L., et al. (1999) J. Biol. Chem. 274, 24906-24913). Here, we compared the binding of the recombinant A-domain of alpha(2)beta(1) (alpha(2)A) to type I collagen with that of alpha(1)A using surface plasmon resonance and showed that alpha(2)A exhibited only one detectable class of binding sites in type I collagen, with a K(D) of approximately 10 microm at approximately 3 binding sites per collagen molecule. We further demonstrated that alpha(1)A and alpha(2)A competed with each other for binding to type I collagen in enzyme-linked immunosorbent assay (ELISA), suggesting that the binding sites in collagen for the two A-domains overlap or are adjacent to each other. By using rotary shadowing, the complexes of alpha(1)A- and alpha(2)A-procollagen were visualized. Morphometric analyses indicated three major binding regions (near the N terminus, in the central part, and near the C terminus) along the type I procollagen molecule for both A-domains. The positions of the respective binding regions for alpha(1)A and alpha(2)A were overlapping with or adjacent to each other, consistent with the ELISA results. Analysis of the sequences of type I collagen revealed that GER or GER-like motifs are present at each of the binding regions, and notably, the central region contains the GFOGER sequence, which was previously identified as a high affinity site for both alpha(1)A and alpha(2)A (Knight, C. G., et al. (2000) J. Biol. Chem. 275, 35-40). Peptides containing GLOGERGRO (peptide I, near the N terminus), GFOGERGVQ (peptide II, central), and GASGERGPO (peptide III, near the C terminus) were synthesized. Peptides I and II effectively inhibited the binding of alpha(1)A and alpha(2)A to type I collagen, while peptide III did so moderately. The N-terminal site in type I collagen has the sequence GLOGER in all three chains. Thus, it seems that peptide I represents a newly discovered native high affinity site for alpha(1)A and alpha(2)A.

Improving foot care for people with diabetes mellitus--a randomized controlled trial of an integrated care approach.

AIMS: To evaluate a model of integrated diabetic footcare, for identification and clinical management of the high risk diabetic foot, centred on the primary care-based diabetic annual review. METHODS: A pragmatic randomized controlled study was undertaken with matched cluster randomization of practices from 10 towns drawn from mid and east Devon responsible for the care of 1,939 people with diabetes (age > or =18 years). Outcome measures were patients' attitudes regarding the value and importance of footcare, patients' footcare knowledge, healthcare professionals' footcare knowledge and pattern of service utilization. RESULTS: Attitudes towards footcare improved in both intervention and control groups (mean percentage change 3.91, 0.68) with a significant difference in change of 3.18 (95% confidence interval (CI) 1.29-5.07) between the groups. Patients' knowledge about diabetic foot problems improved significantly in both groups (mean percentage change 1.09, 1.32) but with no significant difference in change: -0.09 (95% CI -1.81-1.63) between groups. Health professionals' knowledge scores improved in the intervention group (mean percentage change 13.2; P < 0.001). No improvement was seen in the control group (mean percentage change -0.2; P = 0.1) with a significant difference in change of 13.46 (95% CI 8.30-18.62) between groups. Appropriate referrals from intervention practices to the specialized foot clinic rose significantly (P = 0.05) compared with control practices (P = 0.14). CONCLUSIONS: Provision of integrated care arrangements for the diabetic foot has a positive impact on primary care staffs' knowledge and patients' attitudes resulting in an increased number of appropriate referrals to acute specialist services.