Long-term trajectories of densely reported depressive symptoms during an extended period of the COVID-19 pandemic in Switzerland: Social worries matter.

Previous mental health trajectory studies were mostly limited to the months before access to vaccination. They are not informing on whether public mental health has adapted to the pandemic. The aim of this analysis was to 1) investigate trajectories of monthly reported depressive symptoms from July 2020 to December 2021 in Switzerland, 2) compare average growth trajectories across regions with different stringency phases, and 3) explore the relative impact of self-reported worries related to health, economic and social domains as well as socio-economic indicators on growth trajectories. As part of the population-based Corona Immunitas program of regional, but harmonized, adult cohorts studying the pandemic course and impact, participants repeatedly reported online to the DASS-21 instrument on depressive symptomatology. Trajectories of depressive symptoms were estimated using a latent growth model, specified as a generalised linear mixed model. The time effect was modelled parametrically through a polynomial allowing to estimate trajectories for participants' missing time points. In all regions level and shape of the trajectories mirrored those of the KOF Stringency-Plus Index, which quantifies regional Covid-19 policy stringency. The higher level of average depression in trajectories of those expressing specific worries was most noticeable for the social domain. Younger age, female gender, and low household income went along with higher mean depression score trajectories throughout follow-up. Interventions to promote long-term resilience are an important part of pandemic preparedness, given the observed lack of an adaptation in mental health response to the pandemic even after the availability of vaccines in this high-income context.

[Multilocular hepatic masses due to Enterobius vermicularis]. / Multilokuläre hepatische Raumforderungen durch Enterobius vermicularis.

Infestation with Enterobius vermicularis involving extraintestinal manifestation is rare. In a 50-year-old man with lower abdominal pain, computed tomography led to a suspected diagnosis of sigmoid carcinoma with liver metastasis. After ruling out colon cancer by endoscopy, laparoscopic resection of one suspected tumor nodule in the liver was performed. Histopathological examination revealed parasitic granulomas containing pinworms. Hematogenous migration was postulated in the setting of phlebitis with thrombosis of the inferior mesenteric vein.

The molecular structure and multifunctionality of the cryptic plant polymer suberin.

Suberin, a plant polyester, consists of polyfunctional long-chain fatty acids and glycerol and is an intriguing candidate as a novel antimicrobial material. We purified suberin from cork using ionic-liquid catalysis during which the glycerol bonds that ensure the polymeric nature of suberin remained intact or were only partially cleaved-yielding the closest to a native configuration reported to date. The chemistry of suberin, both in situ (in cryogenically ground cork) and ex situ (ionic-liquid extracted), was elucidated using high-resolution one- and two-dimensional solution-state NMR analyses. Centrifugation was used to isolate suberin particles of distinct densities and their monomeric composition, assembly, and bactericidal effect, inter alia, were assessed. Analysis of the molecular structure of suberin revealed the relative abundance of linear aliphatic vs. acylglycerol esters, comprising all acylglycerol configurations and the amounts of total carbonyls (C[bond, double bond]O), free acid end groups (COOH), OH aliphatics, and OH aromatics. Suberin centrifuged fractions revealed generic physiochemical properties and monomeric composition â€‹and self-assemble into polygonal structures that display distinct degrees of compactness when lyophilized. Suberin particles-suberinsomes-display bactericidal activity against major human pathogenic bacteria. Fingerprinting the multifunctionality of complex (plant) polyesters such as suberin allows for the identification of novel polymer assemblies with significant value-added properties.

Creating artificial Rhino Horns from Horse Hair.

Demand for rhino horn is driving poaching with devastating effect for the few individuals left of the few species surviving from this once numerous, widespread and cosmopolitan clade of pachyderms. We bundled together tail hairs of the rhino's ubiquitous near relative, the horse, to be glued together with a bespoke matrix of regenerated silk mimicking the collagenous component of the real horn. This approach allowed us to fabricate composite structures that were confusingly similar to real rhino horn in look, feel and properties. Spectral and thermal FT-IR, DSC and TGA analysis demonstrated the similar chemical composition and thermo-mechanical properties between the natural and the faux horns.

Decoding the locational information in the orb web vibrations of Araneus diadematus and Zygiella x-notata.

A spider's web is a multifunctional structure that captures prey and provides an information platform that transmits vibrational information. Many physical factors interact to influence web vibration and information content, from vibration source properties and input location, to web physical properties and geometry. The aim of the study was to test whether orb web vibration contains information about the location of the source of vibration. We used finite-element analysis model webs to control and vary major physical factors, investigating webs where spiders use a direct or remote monitoring strategy. When monitoring with eight sensors (legs) at the web centre, a comparison of longitudinal and transverse wave amplitude between the sensors gave sufficient information to determine source direction and distance, respectively. These localization cues were robust to changes in source amplitude, input angle and location, with increased accuracy at lower source amplitudes. When remotely monitoring the web using a single thread connected to the web's hub (a signal thread), we found that locational information was not available when the angle of the source input was unknown. Furthermore, a free sector and a stiff hub were physical mechanisms to aid information transfer, which provides insights for bioinspired fibre networks for sensing technologies.

Dynamic shear analysis: a novel method to determine mechanical integrity of normal and torn human acetabular labra: Implications for prediction of outcome of repair.

OBJECTIVES: The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue. METHODS: A total of 47 human labral specimens were obtained from a biobank. These included 22 torn specimens and 25 control specimens from patients undergoing total hip arthroplasty with macroscopically normal labra. The specimens underwent dynamic shear analysis using a rheometer to measure storage modulus, as an indicator of structural integrity. RESULTS: There was a significant difference in the storage modulus between torn (mean modulus = 2144.08 Pa) and non-torn (3178.1 Pa) labra (p = 0.0001). CONCLUSION: The acetabular labrum of young patients with a tear has significantly reduced structural integrity compared with a non-torn labrum in older patients with end-stage osteoarthritis. This study contributes to the understanding of the biomechanics of labral tears, and the observation of reduced structural integrity in torn labra may explain why some repairs fail. Our data demonstrate that labral tears probably have a relatively narrow phenotype, presenting a basis for further investigations that will provide quantifiable data to support their classification and a means to develop a standardized surgical technique for their repair. This study also demonstrates the value of novel biomechanical testing methods in investigating pathological tissues of orthopaedic interest.Cite this article: A. K. Woods, J. Broomfield, P. Monk, F. Vollrath, S. Glyn-Jones. Dynamic shear analysis: a novel method to determine mechanical integrity of normal and torn human acetabular labra: Implications for prediction of outcome of repair. Bone Joint Res 2018;7:440-446. DOI: 10.1302/2046-3758.77.BJR-2017-0282.R2.

Remote monitoring of vibrational information in spider webs.

Spiders are fascinating model species to study information-acquisition strategies, with the web acting as an extension of the animal's body. Here, we compare the strategies of two orb-weaving spiders that acquire information through vibrations transmitted and filtered in the web. Whereas Araneus diadematus monitors web vibration directly on the web, Zygiella x-notata uses a signal thread to remotely monitor web vibration from a retreat, which gives added protection. We assess the implications of these two information-acquisition strategies on the quality of vibration information transfer, using laser Doppler vibrometry to measure vibrations of real webs and finite element analysis in computer models of webs. We observed that the signal thread imposed no biologically relevant time penalty for vibration propagation. However, loss of energy (attenuation) was a cost associated with remote monitoring via a signal thread. The findings have implications for the biological use of vibrations by spiders, including the mechanisms to locate and discriminate between vibration sources. We show that orb-weaver spiders are fascinating examples of organisms that modify their physical environment to shape their information-acquisition strategy.

The potential of Antheraea pernyi silk for spinal cord repair.

One of the most challenging applications for tissue regeneration is spinal cord damage. There is no cure for this, partly because cavities and scar tissue formed after injury present formidable barriers that must be crossed by axons to restore function. Natural silks are considered increasingly for medical applications because they are biocompatible, biodegradable and in selected cases promote tissue growth. Filaments from wild Antheraea pernyi silkworms can support axon regeneration in peripheral nerve injury. Here we presented evidence that degummed A. pernyi filaments (DAPF) support excellent outgrowth of CNS neurons in vitro by cell attachment to the high density of arginine-glycine-aspartic acid tripeptide present in DAPF. Importantly, DAPF showed stiffness properties that are well suited to spinal cord repair by supporting cell growth mechano-biology. Furthermore, we demonstrated that DAPF induced no activation of microglia, the CNS resident immune cells, either in vitro when exposed to DAPF or in vivo when DAPF were implanted in the cord. In vitro DAPF degraded gradually with a corresponding decrease in tensile properties. We conclude that A. pernyi silk meets the major biochemical and biomaterial criteria for spinal repair, and may have potential as a key component in combinatorial strategies for spinal repair.

Tuning the instrument: sonic properties in the spider's web.

Spider orb webs are multifunctional, acting to absorb prey impact energy and transmit vibratory information to the spider. This paper explores the links between silk material properties, propagation of vibrations within webs and the ability of the spider to control and balance web function. Combining experimental and modelling approaches, we contrast transverse and longitudinal wave propagation in the web. It emerged that both transverse and longitudinal wave amplitude in the web can be adjusted through changes in web tension and dragline silk stiffness, i.e. properties that can be controlled by the spider. In particular, we propose that dragline silk supercontraction may have evolved as a control mechanism for these multifunctional fibres. The various degrees of active influence on web engineering reveals the extraordinary ability of spiders to shape the physical properties of their self-made materials and architectures to affect biological functionality, balancing trade-offs between structural and sensory functions.

Differential scanning fluorimetry illuminates silk feedstock stability and processability.

The ability to design and implement silk feedstock formulations for tailored spinning has so far eluded the bioengineers. Recently, the high throughput screening technique of differential scanning fluorimetry (DSF) demonstrated the link between the instability transition temperature (Ti) and the processability of the silk feedstock. Using DSF we screened a large set of chemicals known to affect solvent quality. A multivariate analysis of the results shows that, regardless of the diversity of chemicals, three groupings are significantly distinguishable: G1 = similar to native silk; G2 = largely dominated by electrostatic interactions; and G3 = dominated by chelating interactions. We propose a thermodynamic analysis based on a pre- and post-transition fit to estimate the van't Hoff enthalpies (ΔHv) and the instability temperature (Ti). Our analysis shows that the ΔTi and ΔHv values were distinct: G1 (ΔTi = 0.23 ± 0.2; ΔHv = -159.1 ± 5.6 kcal mol(-1)), G2 (ΔTi = -7.3 ± 0.7; ΔHv = -191.4 ± 5.5 kcal mol(-1)), and G3 (ΔTi = -19.9 ± 3.3; ΔHv = -68.8 ± 6.0 kcal mol(-1)). Our analysis further combined the ΔTi value and the ΔHv value using stability ΔΔG to find that G1 only marginally stabilizes native silks (ΔΔG = -0.15 ± 0.04 kcal mol(-1)), whereas G2 and G3 destabilize native silk (ΔΔG = 3.8 ± 0.11 and ΔΔG = 3.8 ± 0.3 kcal mol(-1), respectively). Here our analysis shows that native silk has a complex multistep transition that is possibly non-cooperative. However, all three groupings also show a direct and cooperative transition with varied stabilization effects. This analysis suggests that native silks are able to sample multiple substates prior to undergoing (or to delay) the final transition. We conclude by hypothesizing that the observed energetic plasticity may be mediated by a fragile packaging of the silk tertiary structure that is readily lost when the solvent quality changes.

Histological and mechanical differences in the skin of patients with rectal prolapse.

INTRODUCTION: It is still an enigma that some patients develop rectal prolapse whilst others with similar risk factors do not. Biomechanical assessment of the skin may provide further insight into the aetiology of this complex condition. Elastin fibres are an abundant and integral part of many extracellular matrices and are especially critical for providing the property of elastic recoil to tissues. The significance of elastin fibres is clearly reflected by the numerous human conditions in which a skin phenotype occurs as a result of elastin fibre abnormalities. METHOD: Between January and June 2013, skin specimens were obtained prospectively during surgery on 20 patients with rectal prolapse and 21 patients without prolapse undergoing surgery for other indications. Expression levels of elastin in the skin were measured by Orcein staining, and Image J. Tensile tests were performed using the Zwick Roell device, with custom ceramic clamps. For statistical analysis, Student's t test was used. RESULTS: Histological analysis of prolapse vs control showed percentage dermal elastin fibres of 9 vs 5.8 % (p = 0.001) in males and 6.5 vs 5.3 % (p = 0.05) in females. Patients with more severe prolapse (external) had a significantly (p = 0.05) higher percentage dermal elastin fibres 6.9 vs 6.1 % than internal prolapse. Young's modulus of patients with prolapse was lower in males (3.3 vs 2.8, p = 0.05) and females (3.1 vs 2.7, p = 0.05). CONCLUSION: Patients with prolapse have a higher concentration of elastin fibres in the skin, and these differences are quantitatively demonstrated through mechanical testing. This suggests that the aetiology may be a result of a dysfunction of elastin fibre assembly.

Horses and cows might teach us about human knees.

Our comparative study of the knees of horses and cows (paraphrased as highly evolved joggers and as domesticated couch-potatoes, respectively) demonstrates significant differences in the posterior sections of bovine and equine tibial cartilage, which are consistent with specialisation for gait. These insights were possible using a novel analytical measuring technique based on the shearing of small biopsy samples, called dynamic shear analysis. We assert that this technique could provide a powerful new tool to precisely quantify the pathology of osteoarthritis for the medical field.

Structure and function of the major ampullate spinning duct of the golden orb weaver, Nephila edulis.

Silks are fibres produced by spiders, some insects and even a crustacean, and are formed from protein solution by a pulltrusion process that is not well understood. Here we describe three aspects of the functional anatomy of the spinning apparatus in a spider: (i) changes in the diameter of the duct of the silk gland along its length for individuals at different stages of development, (ii) the correlation between the morphology of the duct and size and (iii) changes in the thickness of the wall of the duct. We conclude that in the distal part of the duct both the lumen's geometry and change in diameter with distance remains remarkably constant as the duct increases in length from moult to moult as the spider grows. This suggests constancy in the region where the nascent silk filament is drawn down within the lumen of the duct, which is likely to be fundamental for forming strong and tough fibres.

Comparing the rheology of mulberry and "wild" silkworm spinning dopes.

Lepidoperan silks provide a superb opportunity for comparative studies of spinning and fiber characteristics. Comparing the four species, Bombyx mori (China), Actias selene (India), Antheraea yamamai (Japan), Gonometa postica (Africa), allows us to examine differences on the family, species, and race levels. Measured rheological properties were consistent with phylogenetic relationships and in the context of resource allocation and gland morphology. We propose that the thorough domestication of the mulberry silkworm B. mori for high silk yield has resulted in a compensatory optimization for spinning efficiency. This is in stark contrast to the wild silkworms, where Saturnids appear to minimize their energetic input toward silk output and G. postica seems to balance both. We conclude that comparative studies provide valuable baseline information for future biomimetic applications and modeling, as well as illuminating biologically important details of silk processing.

Comparing normal and torn rotator cuff tendons using dynamic shear analysis.

This study reports the application of a novel method for quantitatively determining differences in the mechanical properties of healthy and torn rotator cuff tissues. In order to overcome problems of stress risers at the grip-tendon interface that can obscure mechanical measurements of small tendons, we conducted our investigation using dynamic shear analysis. Rotator cuff tendon specimens were obtained from 100 patients during shoulder surgery. They included 82 differently sized tears and 18 matched controls. We subjected biopsy samples of 3 mm in diameter to oscillatory deformation under compression using dynamic shear analysis. The storage modulus (G') was calculated as an indicator of mechanical integrity. Normal tendons had a significantly higher storage modulus than torn tendons, indicating that torn tendons are mechanically weaker than normal tendons (p = 0.003). Normal tendons had a significantly higher mean shear modulus than tendons with massive tears (p < 0.01). Dynamic shear analysis allows the determination of shear mechanical properties of small tissue specimens obtained intra-operatively that could not be studied by conventional methods of tensile testing. These methods could be employed to investigate other musculoskeletal tissues. This pilot study provides some insight into mechanisms that might contribute to the failure of repair surgery, and with future application could help direct the most appropriate treatment for specific rotator cuff tears.

Fourier transform infrared spectroscopic analysis of normal and torn rotator-cuff tendons.

We have used Fourier transform infrared spectroscopy (FTIR) to characterise the chemical and structural composition of the tendons of the rotator cuff and to identify structural differences among anatomically distinct tears. Such information may help to identify biomarkers of tears and to provide insight into the rates of healing of different sizes of tear. The infrared spectra of 81 partial, small, medium, large and massive tears were measured using FTIR and compared with 11 uninjured control tendons. All the spectra were classified using standard techniques of multivariate analysis. FTIR readily differentiates between normal and torn tendons, and different sizes of tear. We identified the key discriminating molecules and spectra altered in torn tendons to be carbohydrates/phospholipids (1030 cm(-1) to 1200 cm(-1)), collagen (1300 cm(-1) to 1700 cm(-1) and 3000 cm(-1) to 3350 cm(-1)) and lipids (2800 cm(-1) to 3000 cm(-1)). Our study has shown that FTIR spectroscopy can identify tears of the rotator cuff of varying size based upon distinguishable chemical and structural features. The onset of a tear is mainly associated with altered structural arrangements of collagen, with changes in lipids and carbohydrates. The approach described is rapid and has the potential to be used peri-operatively to determine the quality of the tendon and the extent of the disease, thus guiding surgical repair.

The role of kinetics of and amide bonding in protein stability.

The physical properties and function of biological tissues depend critically upon the hydration of proteins; in particular, their thermal, mechanical, and chemical stability. Here, we show quantitatively how thermal, mechanical, and chemical conditions can denature a protein. An elastic instability criterion is applied to localised ab initio quantum mechanics simulations of water and amide bond energies to predict both denaturing conditions and the effect of water on the glass transition temperature of a protein. The kinetics of bond instability for denaturation over a wide range of time scales is quantified by an expression for a second order phase change using parameters derived directly from the quantum simulations. We also show how the zero point energy of vibrations in a potential energy well of intermolecular bonding can differentiate between crystal and amorphous states of matter and their corresponding transition temperatures; this is illustrated by calculating the crystal melt and glass transition temperatures of water.

Time-resolved torsional relaxation of spider draglines by an optical technique.

The sensitivity of the torsional pendulum demonstrates the self-shape-memory effect in different types of spider draglines. Here we report the time-resolved noncovalent bonds recovery in the protein structure. The torsional dynamics of such multilevel structure governed by reversible interactions are described in the frame of a nested model. Measurement of three different relaxation times confirms the existence of three energy storage levels in such two protein spidroin systems. Torsion opens the way to further investigations towards unraveling the tiny torque effects in biological molecules.

Comparing the rheology of native spider and silkworm spinning dope.

Silk production has evolved to be energetically efficient and functionally optimized, yielding a material that can outperform most industrial fibres, particularly in toughness. Spider silk has hitherto defied all attempts at reproduction, despite advances in our understanding of the molecular mechanisms behind its superb mechanical properties. Spun fibres, natural and man-made, rely on the extrusion process to facilitate molecular orientation and bonding. Hence a full understanding of the flow characteristics of native spinning feedstock (dope) will be essential to translate natural spinning to artificial silk production. Here we show remarkable similarity between the rheologies for native spider-dragline and silkworm-cocoon silk, despite their independent evolution and substantial differences in protein structure. Surprisingly, both dopes behave like typical polymer melts. This observation opens the door to using polymer theory to clarify our general understanding of natural silks, despite the many specializations found in different animal species.