Multiscale static and dynamic mechanical study of the Turritella terebra and Turritellinella tricarinata seashells

Marine shells are designed by nature to ensure mechanical protection from predators and shelter for molluscs living inside them. A large amount of work has been done to study the multiscale mechanical properties of their complex microstructure and to draw inspiration for the design of impact-resistant biomimetic materials. Less is known regarding the dynamic behaviour related to their structure at multiple scales. Here, we present a combined experimental and numerical study of the shells of two different species of gastropod sea snail belonging to the Turritellidae family, featuring a peculiar helicoconic shape with hierarchical spiral elements. The proposed procedure involves the use of micro-computed tomography scans for the accurate determination of geometry, atomic force microscopy and nanoindentation to evaluate local mechanical properties, surface morphology and heterogeneity, as well as resonant ultrasound spectroscopy coupled with finite element analysis simulations to determine global modal behaviour. Results indicate that the specific features of the considered shells, in particular their helicoconic and hierarchical structure, can also be linked to their vibration attenuation behaviour. Moreover, the proposed investigation method can be extended to the study of other natural systems, to determine their structure-related dynamic properties, ultimately aiding the design of bioinspired metamaterials and of structures with advanced vibration control.

The public health implications of the Paris Agreement: a modelling study

BACKGROUND

nationally determined contributions (NDCs) serve to meet the goals of the Paris Agreement of staying "well below 2°C", which could also yield substantial health co-benefits in the process. However, existing NDC commitments are inadequate to achieve this goal. Placing health as a key focus of the NDCs could present an opportunity to increase ambition and realise health co-benefits. We modelled scenarios to analyse the health co-benefits of NDCs for the year 2040 for nine representative countries (ie, Brazil, China, Germany, India, Indonesia, Nigeria, South Africa, the UK, and the USA) that were selected for their contribution to global greenhouse gas emissions and their global or regional influence.

METHODS

Modelling the energy, food and agriculture, and transport sectors, and mortality related to risk factors of air pollution, diet, and physical activity, we analysed the health co-benefits of existing NDCs and related policies (ie, the current pathways scenario) for 2040 in nine countries around the world. We compared these health co-benefits with two alternative scenarios, one consistent with the goal of the Paris Agreement and the Sustainable Development Goals (ie, the sustainable pathways scenario), and one in line with the sustainable pathways scenario, but also placing health as a central focus of the policies (ie, the health in all climate policies scenario).

FINDINGS

Compared with the current pathways scenario, the sustainable pathways scenario resulted in an annual reduction of 1·18 million air pollution-related deaths, 5·86 million diet-related deaths, and 1·15 million deaths due to physical inactivity, across the nine countries, by 2040. Adopting the more ambitious health in all climate policies scenario would result in a further reduction of 462 000 annual deaths attributable to air pollution, 572 000 annual deaths attributable to diet, and 943 000 annual deaths attributable to physical inactivity. These benefits were attributable to the mitigation of direct greenhouse gas emissions and the commensurate actions that reduce exposure to harmful pollutants, as well as improved diets and safe physical activity.

INTERPRETATION

A greater consideration of health in the NDCs and climate change mitigation policies has the potential to yield considerable health benefits as well as achieve the "well below 2°C" commitment across a range of regional and economic contexts.

FUNDING

This work was in part funded through an unrestricted grant from the Wellcome Trust (award number 209734/Z/17/Z) and supported by an Engineering and Physical Sciences Research Council grant (grant number EP/R035288/1).

The 2020 report of The Lancet Countdown on health and climate change: responding to converging crises

For the Chinese, French, German, and Spanish translations of the abstract see Supplementary Materials section.

Three-dimensional modeling and numerical predictions of multimodal nonlinear behavior in damaged concrete blocks

In this paper, the multimodal nonlinear elastic behavior of concrete, which is representative of a consolidated granular material, is modeled numerically. Starting from a local three-dimensional softening law, the initial stiffness properties are re-estimated according to the local strain field. The experiments deal with samples of thermally damaged concrete blocks successively excited around their first three modes of vibration. The geometry of these samples cannot be described by a one-dimensional approximation in these experiments where compressional and shear motions are strongly coupled. Despite this added complexity, the nonlinear behavior for the three modes of vibration of the samples is well captured by the simulations using a single scalar nonlinear parameter appropriately integrated into the elasticity equations. It is shown that without sufficient attention paid to the latter, the conclusions would have brought erroneous statements such as nonlinearity dispersion or strain type dependence.

The Lancet Countdown: tracking progress on health and climate change

The Lancet Countdown: tracking progress on health and climate change is an international, multidisciplinary research collaboration between academic institutions and practitioners across the world. It follows on from the work of the 2015 Lancet Commission, which concluded that the response to climate change could be "the greatest global health opportunity of the 21st century". The Lancet Countdown aims to track the health impacts of climate hazards; health resilience and adaptation; health co-benefits of climate change mitigation; economics and finance; and political and broader engagement. These focus areas form the five thematic working groups of the Lancet Countdown and represent different aspects of the complex association between health and climate change. These thematic groups will provide indicators for a global overview of health and climate change; national case studies highlighting countries leading the way or going against the trend; and engagement with a range of stakeholders. The Lancet Countdown ultimately aims to report annually on a series of indicators across these five working groups. This paper outlines the potential indicators and indicator domains to be tracked by the collaboration, with suggestions on the methodologies and datasets available to achieve this end. The proposed indicator domains require further refinement, and mark the beginning of an ongoing consultation process-from November, 2016 to early 2017-to develop these domains, identify key areas not currently covered, and change indicators where necessary. This collaboration will actively seek to engage with existing monitoring processes, such as the UN Sustainable Development Goals and WHO's climate and health country profiles. The indicators will also evolve over time through ongoing collaboration with experts and a range of stakeholders, and be dependent on the emergence of new evidence and knowledge. During the course of its work, the Lancet Countdown will adopt a collaborative and iterative process, which aims to complement existing initiatives, welcome engagement with new partners, and be open to developing new research projects on health and climate change.

Dynamic acousto-elastic test using continuous probe wave and transient vibration to investigate material nonlinearity

This study demonstrates the feasibility of the dynamic acousto-elastic effect of a continuous high frequency wave for investigating the material nonlinearity upon transient vibration. The approach is demonstrated on a concrete sample measuring 15×15×60cm(3). Two ultrasonic transducers (emitter and receiver) are placed at its middle span. A continuous high frequency wave of 500kHz propagates through the material and is modulated with a hammer blow. The position of the hammer blow on the sample is configured to promote the first bending mode of vibration. The use of a continuous wave allows discrete time extraction of the nonlinear behavior by a short-time Fourier transform approach, through the simultaneous comparison of a reference non-modulated signal and an impact-modulated signal. The hammer blow results in phase shifts and variations of signal amplitude between reference and perturbed signals, which are driven by the resonant frequency of the sample. Finally, a comprehensive analysis of the relaxation mechanisms (modulus and attenuation recovery) is conducted to untangle the coupled fast and slow hysteretic effects.

[The mitochondrial genome and human mitochondrial diseases]

To date, more than 100 point mutations and several hundreds of structural rearrangements of mitochondrial DNA (mtDNA) are known too be connected with characteristic neuromuscular and other mitochondrial syndromes varying form those causing death at the neonatal stage to diseases with late ages of onset. The immediate cause of mitochondrial disorders is a defective oxidative phosphorylation. Wide phenotypic variation and the heteroplasmy phenomenon, which some authors include in mutation load, are characteristic of human mitochondrial diseases. As the numbers of cases identified and pedigrees described increase, data on the genotype--phenotype interaction and the structure and frequency of pathogenic and conditionally pathogenic mtDNA mutations in human populations are rapidly accumulated. The data on the genetics and epidemiology of mitochondrial diseases are not only important for differential diagnosis and genetic counseling. Since both neutral and mildly pathogenic mutations of mtDNA are progressively accumulated in maternal phyletic lines, molecular analysis of these mutations permits not only reconstruction of the genealogical tree of modern humans, but also estimation of the role that these mutations play in natural selection.

Brush cytology in the diagnosis of neoplasia in Barrett's esophagus

Esophageal cytology may improve sensitivity for the detection of malignancy but can be difficult to interpret in the presence of inflammation. To assess the value of cytology in assessing patients with Barrett's esophagus a retrospective review was performed. One hundred and sixty two patients (87 esophageal/gastroesophageal junction adenocarcinoma, 65 non-dysplastic Barrett's esophagus and 10 dysplastic Barrett's esophagus) had biopsies and brushings taken for histological and cytological assessment. Eighty two of 92 patients with carcinoma or high-grade dysplasia had true positive malignant cytology. Seven of 65 patients with non-dysplastic but inflamed Barrett's esophagus had false positive malignant cytology. One of these patients had an esophagectomy on the basis of cytology but no tumor was found in the resection specimen. This translates into an 89% sensitivity and specificity of cytology for the detection of esophageal columnar neoplasia. Cytology from Barrett's esophagus can be misleading in the presence of severe inflammation. Cells from a benign Barrett's ulcer may appear frankly malignant when examined in isolation. Esophagectomy should not be performed on the basis of cytological evidence alone.

Brofaromine for social phobia: a multicenter, placebo-controlled, double-blind study

The safety and efficacy of brofaromine, a reversible and selective monoamine oxidase inhibitor, were examined in a multicenter trial of 102 outpatients with social phobia. After a 1-week placebo washout, subjects were randomly assigned to 10 weeks of treatment with either brofaromine (N = 52) or placebo (N = 50). Brofaromine dosage began at 50 mg/day and was titrated to a maximum of 150 mg/day, depending on treatment response. Brofaromine produced a significantly greater change from baseline in Liebowitz Social Anxiety Scale (LSAS) scores compared with placebo, F(1) = 6.01, p < 0.016. Mean LSAS scores decreased from 81.8 at baseline to 62.6 at endpoint for brofaromine, t = 5.41,p < 0.001, and from 79.8 to 70.7 for placebo, t = 3.66, p < 0.001. Eleven of the 14 brofaromine early terminators discontinued because of adverse experiences, as did 4 of the 17 placebo early terminators. Side effects more common with brofaromine than placebo included insomnia, dizziness, dry mouth, anorexia, tinnitus, and tremor. No clinically significant variations in vital signs or laboratory values were found. The findings are consistent with the clinical efficacy for the treatment of social phobia.

Choriocarcinoma presenting as a breast lump

A case of choriocarcinoma in a previously well 32-year-old woman presenting as a tender breast lump whilst she is breastfeeding.

Mitochondrial encephalomyopathy associated with a single nucleotide pair deletion in the mitochondrial tRNALeu(UUR) gene

The investigation of pathogenic mitochondrial DNA (mtDNA) mutations has revealed a complex relation between patient genotype and phenotype. For unknown reasons, some mtDNA mutations produce specific clinical manifestations such as chronic progressive external ophthalmoplegia; myoclonic epilepsy and ragged-red fiber disease (MERRF); and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). To enhance our understanding of the association between genotype and phenotype, we investigated a patient with mitochondrial encephalomyopathy and severe cerebral calcifications for a mtDNA mutation. There was a deletion of one of three T:A nucleotide pairs in the tRNALeu(UUR) gene of the mtDNA involving positions 3271 to 3273. Pedigree analysis suggested that this mutation may have occurred spontaneously in the proband. This analysis represents the smallest mtDNA deletion observed to date and is the first deletion identified within a mitochondrial tRNA. This observation emphasizes the importance of delineating the precise mutation responsible for an oxidative phosphorylation disease for patient diagnosis as well as for genetic counseling of maternal lineage relatives.

Serotonergic (5-HT2) mediation of anxiety-therapeutic effects of serazepine in generalized anxiety disorder

Serotonin 1a and serotonin-2 receptors are implicated in anxiety. Serazepine (CGS-15040A, (R,S)-1,3,4,16b-Tetrahydro-2-methyl-2H,10H-indolo[2,1-c] Pyrazino-[1,2-a][1,4] benzodiazepine-16-carboxylic acid, methyl ester hydrochloride]) is a representative of a novel pentacyclic ring system containing a stabilized indole. In chemical assays it was a highly specific inhibitor of serotonin (5-HT2) binding, and it was active in preliminary preclinical assays of anxiolytic potential. This multicenter trial of CGS-15040A in patients with generalized anxiety disorder demonstrated clinical anxiolytic effects consistent with established preclinical effects. Doses greater than or equal to 10 mg reduced Hamilton Anxiety Scale scores. However, the dose-response relationship was nonlinear. Effects appeared primarily related to the psychic components of anxiety.

A clinical test of noradrenergic involvement in the therapeutic mode of action of an experimental antidepressant

The noradrenaline (NA) hypothesis of depression is founded primarily on preclinical and clinically indirect evidence. In two three-compartment randomized parallel clinical trials conducted serially, we examined the significance of NA uptake for antidepressant activity. The racemic compound oxaprotiline (hydroxymaprotiline) is a highly specific inhibitor of NA uptake, whereas its R-(-) enantiomer levoprotiline is totally devoid of this property. Oxaprotiline significantly resembled amitriptyline in its antidepressant potential. Conversely, levoprotiline significantly resembled placebo in antidepressant potential. Therefore, NA uptake was necessary for the observed therapeutic effect of this experimental antidepressant.

CAI: a strategy for retaining minority and academically disadvantaged students

A computer assisted instruction (CAI) program was implemented as a teaching-learning strategy to retain students with academic deficiencies and increase their chances of being successful. The CAI programs were based on curriculum, course, and specific unit objectives. The CAI programs helped reduce the number of student failures in a medical-surgical nursing course which previously had a high attrition rate. The authors discuss the potential CAI has for assisting minority and disadvantaged students in successfully completing the baccalaureate nursing program.

Tumour thickness in malignant melanoma: the limitations of frozen section

This paper reports a prospective study to compare maximal tumour thickness values of the same lesion obtained by frozen and paraffin sections in 20 patients with malignant melanoma over a one-year period. Significant differences were found between tumour thickness values obtained by frozen section and paraffin section. There was no constant relationship between the two sets of values. As present prognostic and therapeutic criteria are based on tumour thickness measurements obtained from paraffin sections, we recommend that clinical decisions should not be based on results obtained from frozen sections.

Renal medullary "rings": possible CT manifestation of hypercalcemia

Bilateral dense rings in the renal medulla were found on noncontrasted computed tomography in a patient with marked hypercalcemia and suspected primary hyperparathyroidism. The rings were not present on plain radiographs and were obscured on contrasted scans, and may represent occult nephrocalcinosis. Associated findings--renal insufficiency induced by hypercalcemia and interstitial nephritis--may be reversible with early recognition of this CT finding.

Massive retroperitoneal lymphadenopathy as a terminal event in hairy cell leukaemia

A case of hairy cell leukaemia complicated as a terminal event by massive retroperitoneal lymphadenopathy is described. The patient had recently been treated with lithium carbonate and had previously been demonstrated to suffer from a systemic vasculitis, either or both of which may have contributed to the development of this rare complication.

Transmission of salmonid whirling disease by birds fed trout infected with Myxosoma cerebralis

Mallard ducks, Anas platyrhynchos and a black crested night heron, Nycticorax nycticorax were fed trout infected with Myxosoma cerebralis (HOFER) in 2 separate experiments. Feces from the birds were deposited in troughs containing M. cerebralis-free mud as well as in 1 trough without mud. Spore suspensions were also added directly to mud in 1 trough and to another without mud. Susceptible rainbow trout, Salmo gairdneri, developed whirling disease in all troughs containing mud contaminated with M. cerebralis but remained free of infection when exposed to M. cerebralis in troughs without mud. This demonstrates the possibility of bird transmission of the organism causing whirling disease to previously non-contaminated waters.