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Synthetic biology has a huge potential to produce the next generation of advanced materials by accessing previously unreachable (bio)chemical space. In this prospective review, we take a snapshot of current activity in this rapidly developing area, focusing on prominent examples for high-performance applications such as those required for protective materials and the aerospace sector. The continued growth of this emerging field will be facilitated by the convergence of expertise from a range of diverse disciplines, including molecular biology, polymer chemistry, materials science, and process engineering. This review highlights the most significant recent advances and addresses the cross-disciplinary challenges currently being faced.
Geosphere-biosphere interactions are ubiquitous features of the Earth surface, yet the development of interactions between newly exposed lithologic surfaces and colonizing plants during primary succession after glaciation are lacking temporal detail. To assess the nature, rate, and magnitude of vegetation influence on parent material and sediment delivery, we analyzed ecosystem and geochemical proxies from lacustrine sediment cores at a grassland site and a forested site in the northern United States. Over time, terrigenous inputs declined at both sites, with increasing amounts of organic inputs toward present. The similarities between sites were striking given that the grassland sequence began in the Early Holocene, and the forested sequence began after the last glacial maximum. Multiple mechanisms of chemical weathering, hydrologic transport, and changes in source material potentially contribute to this pattern. Although there were strong links between vegetation composition and nitrogen cycling at each site, it appears that changes in forest type, or from oak woodland to grassland, did not exert a large influence on elemental (K, Ti, Si, Ca, Fe, Mn, and S) abundance in the sedimentary sequences. Rather, other factors in the catchment-lake system determined the temporal sequence of elemental abundance.
A new deep level transient spectroscopy (DLTS) technique is described, called half-width at variable intensity analysis. This method utilizes the width and normalized intensity of a DLTS signal to determine the activation energy and capture cross section of the trap that generated the signal via a variable, kO. This constant relates the carrier emission rates giving rise to the differential capacitance signal associated with a given trap at two different temperatures: the temperature at which the maximum differential capacitance is detected, and an arbitrary temperature at which some nonzero differential capacitance signal is detected. The extracted activation energy of the detected trap center is used along with the position of the peak maximum to extract the capture cross section of the trap center.
Studies have been made of the application of X-ray spectrography to continuous analysis for process control. To date the most widespread application of fluorescent X-ray spectrography to process control has been in measurement of plating thickness. Realizing that many other processes could use a method of continuous analysis of moving materials, these studies were undertaken.
A modified tube housing and sample holder was constructed so that material could be passed through the X-ray beam, of a conventional X-ray spectrograph at various linear speeds. Detectability versus material speeds were studied for a number of elements in various mediums.
Application of fluorescent X-ray spectrography as a continuous analytical tool looks very promising. Further studies on specific plant problems should provide useful and advantageous industrial applications of the basic information developed here.
Small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (WAXD) data are used to establish relationships among the degree of crystallinity, melting temperature and lamellar thickness for random copolymers of poly(β-hydroxybutyrate-co-β-hydroxyvaierate) (PHB/V). The morphology of this isodimorphic system is best described by a two phase model consisting of crystalline and amorphous domains having density fluctuations within each domain. The Sanchez-Eby inclusion model is used to predict melting point depression in these materials and, combined with SAXS data, to gain insight into the degree of inclusion of hydroxy valerate units within the polyhydroxybutyrate crystalline domains.
The euarthropod Luohuilinella deletres sp. nov. is described from rare material from the Chengjiang biota, Cambrian Series 2, Stage 3, of Yunnan Province, China. Phylogenetic analysis recovers a xandarellid affinity for L. deletres, representing only the fifth described species of this clade. L. deletres possesses a head shield that is about one-fifth of the total body length and a trunk with 30 tergites, the reduced anterior-most tergite and terminal three tergites lacking pleural elongations. Anteriorly situated notches in the head shield are associated with stalked eyes, in contrast to the more posterior, enclosed eye slits present in Xandarella. Posterior to the antennae there are at least 11 pairs of biramous appendages preserved, including three pairs in the head. The morphology of the midline gut of L. deletres, in which lateral, unbranched diverticula are wider towards the front of the body, is a characteristic also found in various trilobites. The dorsoventrally flattened exoskeleton suggests a benthic or nektobenthic mode of life for L. deletres, as for other trilobitomorphs, and it likely used its well-developed anteriorly positioned eyes for searching out food, either to scavenge or to find prey.
Radiocarbon (14C or carbon-14, half-life 5730 yr) is a key radionuclide in the assessment of the safety of a geological disposal facility (GDF) for radioactive waste. In particular, the radiological impact of gaseous carbon-14 bearing species has been recognized as a potential issue. Irradiated steels are one of the main sources of carbon-14 in the United Kingdom’s radioactive waste inventory. However, there is considerable uncertainty about the chemical form(s) in which the carbon-14 will be released. The objective of the work was to measure the rate and speciation of carbon-14 release from irradiated 316L(N) stainless steel on leaching under high-pH anoxic conditions, representative of a cement-based near field for low-heat generating wastes. Periodic measurements of carbon-14 releases to both the gas phase and to solution were made in duplicate experiments over a period of up to 417 days. An initial fast release of carbon-14 from the surface of the steel is observed during the first week of leaching, followed by a drop in the rate of release at longer times. Carbon-14 is released primarily to the solution phase with differing fractions released to the gas phase in the two experiments: about 1% of the total release in one and 6% in the other. The predominant dissolved carbon-14 releases are in inorganic form (as 14C-carbonate) but also include organic species. The predominant gas-phase species are hydrocarbons with a smaller fraction of 14CO (which may include some volatile oxygen-containing carbon-species). The experiments are continuing, with final sampling and termination planned after leaching for a total of two years.
The OSU-FEI Electron Microscopy Collaboratory multiplies the number of individuals who can experience hands-on advanced microscopy techniques. The microscopy classroom allows up to 33 attendees to operate, individually and in real time, electron microscopes as if they were sitting in front of the actual instruments. The communications link, a fast backbone augmented by Internet2, allows various microscopes to be operated from the classroom or by collaborators in another city. This system transforms the training of new users from a one-person-at-a-time session with an expert operator to a group collaborative activity that can include users from around the world.
In “Toward a Theory of Race, Crime, and Urban Inequality,” Sampson and Wilson (1995) argued that racial disparities in violent crime are attributable in large part to the persistent structural disadvantages that are disproportionately concentrated in African American communities. They also argued that the ultimate causes of crime were similar for both Whites and Blacks, leading to what has been labeled the thesis of “racial invariance.” In light of the large scale social changes of the past two decades and the renewed political salience of race and crime in the United States, this paper reassesses and updates evidence evaluating the theory. In so doing, we clarify key concepts from the original thesis, delineate the proper context of validation, and address new challenges. Overall, we find that the accumulated empirical evidence provides broad but qualified support for the theoretical claims. We conclude by charting a dual path forward: an agenda for future research on the linkages between race and crime, and policy recommendations that align with the theory’s emphasis on neighborhood level structural forces but with causal space for cultural factors.
Isotopic investigations of human burials from excavations of the Autonomous University of Campeche (CIHS) at the prehispanic Maya capital of Calakmul in southeastern Mexico, near the border with Guatemala, include determination of radiocarbon dates; carbon and nitrogen isotope ratios in collagen; and strontium, carbon, and oxygen isotope ratios in tooth enamel. A total of 22 human and 5 faunal samples analyzed for strontium isotopes reveal a narrow range of variation in values, pointing to the likely local origin of over two-thirds of the central population of Calakmul, including two of its rulers. Carbon and nitrogen data confirm a typical Classic Maya diet at the site and identify a diet high in meat consumption for one dynastic individual. Interpreted jointly, the isotopic information offers new perspectives on the provenience and lifestyles of the residents of Calakmul, including a potential place of origin for the royal occupant of chamber tomb Burial VII-1.
Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88) presented a critique of our recently published paper in Cell Reports entitled ‘Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets’ (Lam et al., Cell Reports, Vol. 21, 2017, 2597–2613). Specifically, Hill offered several interrelated comments suggesting potential problems with our use of a new analytic method called Multi-Trait Analysis of GWAS (MTAG) (Turley et al., Nature Genetics, Vol. 50, 2018, 229–237). In this brief article, we respond to each of these concerns. Using empirical data, we conclude that our MTAG results do not suffer from ‘inflation in the FDR [false discovery rate]’, as suggested by Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88), and are not ‘more relevant to the genetic contributions to education than they are to the genetic contributions to intelligence’.
Neothaumalea atlanticanew genus, new species (Diptera: Thaumaleidae), is described from the state of Santa Catarina in southern Brazil. This represents the first thaumaleid collected east of the Andes mountain range. The egg, larva, pupa, and both adults are described and illustrated, distribution map presented, and phylogenetic affinities discussed. A key to the genera of South America is also provided.
To evaluate probiotics for the primary prevention of Clostridium difficile infection (CDI) among hospital inpatients.
A before-and-after quality improvement intervention comparing 12-month baseline and intervention periods.
A 694-bed teaching hospital.
We administered a multispecies probiotic comprising L. acidophilus (CL1285), L. casei (LBC80R), and L. rhamnosus (CLR2) to eligible antibiotic recipients within 12 hours of initial antibiotic receipt through 5 days after final dose. We excluded (1) all patients on neonatal, pediatric and oncology wards; (2) all individuals receiving perioperative prophylactic antibiotic recipients; (3) all those restricted from oral intake; and (4) those with pancreatitis, leukopenia, or posttransplant. We defined CDI by symptoms plus C. difficile toxin detection by polymerase chain reaction. Our primary outcome was hospital-onset CDI incidence on eligible hospital units, analyzed using segmented regression.
The study included 251 CDI episodes among 360,016 patient days during the baseline and intervention periods, and the incidence rate was 7.0 per 10,000 patient days. The incidence rate was similar during baseline and intervention periods (6.9 vs 7.0 per 10,000 patient days; P=.95). However, compared to the first 6 months of the intervention, we detected a significant decrease in CDI during the final 6 months (incidence rate ratio, 0.6; 95% confidence interval, 0.4–0.9; P=.009). Testing intensity remained stable between the baseline and intervention periods: 19% versus 20% of stools tested were C. difficile positive by PCR, respectively. From medical record reviews, only 26% of eligible patients received a probiotic per the protocol.
Despite poor adherence to the protocol, there was a reduction in the incidence of CDI during the intervention, which was delayed ~6 months after introducing probiotic for primary prevention.
UK Biobank is a well-characterised cohort of over 500 000 participants that offers unique opportunities to investigate multiple diseases and risk factors.
An online mental health questionnaire completed by UK Biobank participants was expected to expand the potential for research into mental disorders.
An expert working group designed the questionnaire, using established measures where possible, and consulting with a patient group regarding acceptability. Case definitions were defined using operational criteria for lifetime depression, mania, anxiety disorder, psychotic-like experiences and self-harm, as well as current post-traumatic stress and alcohol use disorders.
157 366 completed online questionnaires were available by August 2017. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status than the general population across a range of indicators. Thirty-five per cent (55 750) of participants had at least one defined syndrome, of which lifetime depression was the most common at 24% (37 434). There was extensive comorbidity among the syndromes. Mental disorders were associated with high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation.
The questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed owing to selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health.
Declaration of interest
G.B. received grants from the National Institute for Health Research during the study; and support from Illumina Ltd. and the European Commission outside the submitted work. B.C. received grants from the Scottish Executive Chief Scientist Office and from The Dr Mortimer and Theresa Sackler Foundation during the study. C.S. received grants from the Medical Research Council and Wellcome Trust during the study, and is the Chief Scientist for UK Biobank. M.H. received grants from the Innovative Medicines Initiative via the RADAR-CNS programme and personal fees as an expert witness outside the submitted work.
The History, Electrocardiogram (ECG), Age, Risk Factors, and Troponin (HEART) score is a decision aid designed to risk stratify emergency department (ED) patients with acute chest pain. It has been validated for ED use, but it has yet to be evaluated in a prehospital setting.
A prehospital modified HEART score can predict major adverse cardiac events (MACE) among undifferentiated chest pain patients transported to the ED.
A retrospective cohort study of patients with chest pain transported by two county-based Emergency Medical Service (EMS) agencies to a tertiary care center was conducted. Adults without ST-elevation myocardial infarction (STEMI) were included. Inter-facility transfers and those without a prehospital 12-lead ECG or an ED troponin measurement were excluded. Modified HEART scores were calculated by study investigators using a standardized data collection tool for each patient. All MACE (death, myocardial infarction [MI], or coronary revascularization) were determined by record review at 30 days. The sensitivity and negative predictive values (NPVs) for MACE at 30 days were calculated.
Over the study period, 794 patients met inclusion criteria. A MACE at 30 days was present in 10.7% (85/794) of patients with 12 deaths (1.5%), 66 MIs (8.3%), and 12 coronary revascularizations without MI (1.5%). The modified HEART score identified 33.2% (264/794) of patients as low risk. Among low-risk patients, 1.9% (5/264) had MACE (two MIs and three revascularizations without MI). The sensitivity and NPV for 30-day MACE was 94.1% (95% CI, 86.8-98.1) and 98.1% (95% CI, 95.6-99.4), respectively.
Prehospital modified HEART scores have a high NPV for MACE at 30 days. A study in which prehospital providers prospectively apply this decision aid is warranted.
The Neotoma Paleoecology Database is a community-curated data resource that supports interdisciplinary global change research by enabling broad-scale studies of taxon and community diversity, distributions, and dynamics during the large environmental changes of the past. By consolidating many kinds of data into a common repository, Neotoma lowers costs of paleodata management, makes paleoecological data openly available, and offers a high-quality, curated resource. Neotoma’s distributed scientific governance model is flexible and scalable, with many open pathways for participation by new members, data contributors, stewards, and research communities. The Neotoma data model supports, or can be extended to support, any kind of paleoecological or paleoenvironmental data from sedimentary archives. Data additions to Neotoma are growing and now include >3.8 million observations, >17,000 datasets, and >9200 sites. Dataset types currently include fossil pollen, vertebrates, diatoms, ostracodes, macroinvertebrates, plant macrofossils, insects, testate amoebae, geochronological data, and the recently added organic biomarkers, stable isotopes, and specimen-level data. Multiple avenues exist to obtain Neotoma data, including the Explorer map-based interface, an application programming interface, the neotoma R package, and digital object identifiers. As the volume and variety of scientific data grow, community-curated data resources such as Neotoma have become foundational infrastructure for big data science.