Cryofouling avoidance in the Antarctic scallop Adamussium colbecki

The presence of supercooled water in polar regions causes anchor ice to grow on submerged objects, generating costly problems for engineered materials and life-endangering risks for benthic communities. The factors driving underwater ice accretion are poorly understood, and passive prevention mechanisms remain unknown. Here we report that the Antarctic scallop Adamussium colbecki appears to remain ice-free in shallow Antarctic marine environments where underwater ice growth is prevalent. In contrast, scallops colonized by bush sponges in the same microhabitat grow ice and are removed from the population. Characterization of the Antarctic scallop shells revealed a hierarchical micro-ridge structure with sub-micron nano-ridges which promotes directed icing. This concentrates the formation of ice on the growth rings while leaving the regions in between free of ice, and appears to reduce ice-to-shell adhesion when compared to temperate species that do not possess highly ordered surface structures. The ability to control the formation of ice may enable passive underwater anti-icing protection, with the removal of ice possibly facilitated by ocean currents or scallop movements. We term this behavior cryofouling avoidance. We posit that the evolution of natural anti-icing structures is a key trait for the survival of Antarctic scallops in anchor ice zones.This work was supported by the European Union’s Horizon 2020 research and innovation program LubISS No. 722497 (W.S.Y.W.), the German Research Foundation (DFG) with the Priority Programme 2171 (L.H.), the NSF Award No. OPP 1559691 (P.A.C.). The Antarctic fieldwork was supported by the US Antarctic Program under OPP 1559691 to P.A.C. and OPP 1341612 to S. Bowser. We thank S. Bowser, H. Kaiser, and M. Koonce for their assistance in the field, G. Glaser, R. Berger, H. Burg for technical support, A. Naga, D. Vollmer, H.-J. Butt, and M. Bonn for stimulating discussions and the reviewers L. Harper and J. Raymond, whose comments helped to improve this manuscript.Ye

Wetting Mechanisms on Silicone Surfaces with Liquid, Frozen, and Vaporous Water

Silicone coatings show low contact friction, water repellency, and high mobility of wetting drops - features that are necessary for self-cleaning, lubrication, anti-icing/-biofouling, drag-reduction, and enhanced heat and mass transfer. For this, silicone coatings are found in numerous fields, such as life science, aerospace, automotive, and electronic industry. Silicones comprise polymeric chains; the most abundant silicone is polydimethylsiloxane (PDMS). PDMS is benign, environmentally friendly, safe, and easy to process, while its material properties are highly tunable. In the following, three distinct PDMS coatings are considered, which are distinguished by chain reticulation: PDMS oil coatings (mobile chains), PDMS elastomer coatings (crosslinked chains), and PDMS chain coatings (single-grafted chains). Contacting drops (and solids, too) induce shape and/or composition adaptations on the PDMS coating. Such wetting-induced coating responses alter the contact friction temporally and may cause irreversible structural degradation, over time. When phase change (condensation/sublimation/frosting) is involved the coating response (contact friction and surface deterioration) can be different. Understanding the coating responses to imposed wetting scenarios (e.g. forced wetting or phase change) is pivotal for smart coating designs with optimized and lasting surface functionality. Gaining insight, however, is challenging as the surface responses scatter over orders of magnitude on time and length scales, a multitude of physical and chemical concepts are involved, and the wetting interplayers are highly coupled. This brings even modern experimental and numerical methods to their limits and the full spectrum of surface responses is still elusive. In this cumulative dissertation, I explore wetting-associated mechanisms (i.e., drop sliding, condensation, frosting, and sorption) on PDMS coatings (i.e., oil, elastomer). I utilize micro- and macroscopic visualization (e.g. confocal microscopy) of different wetting scenarios. I focus on non-equilibrium wetting processes (e.g. drop sliding or frost formation) to explore the dynamic response of the PDMS coating. I use continuum mechanical and thermodynamical concepts to model experimental observations analytically and numerically. This complementary approach delivers a fundamental understanding of the wetting interactions on a theoretical level, supported by experimental evidence. This understanding allows coating and application to be matched, providing optimized surface functionality. In cases of mismatches, the surface may malfunction and degrade over time. In particular, I illustrate this with moving drops on PDMS elastomers: fast drop movement yields high surface dissipation, thus, poor drop mobility. However, slow movement yields strong surface deterioration as the coating material is (partially) entrained by the drop. The optimal operation point is met at intermediate sliding speeds, where surface dissipation and deterioration are low. In another demonstration, I show this optimal operation point for PDMS oil coatings under frost conditions: when frost forms fast and spiky, and the oil retention on the surface is poor, rapid oil depletion is unavoidable. The optimal operating point is found in warmer, very dry, or very humid atmospheres while the surface is equipped with nanometric scaffold structures to increase oil retention

General and oral health status of preterm one-year-old very low and extremely low birthweight infants (a cross - sectional study)

Aims. The aim of the present study was to evaluate the general and oral health status of a group of preterm one-year-old very low (VLBW) and extremely low birthweight (ELBW) infants and make a comparison with full-term one-year-old normal birthweight infants (NBW). Methods. A cross-sectional study was conducted in 102 one-year-old preterm VLBW and ELBW infants, and the data obtained were compared to 87 one-year-old full-term NBW infants. The infants' medical histories were obtained from hospital records and interviews with the mothers. The oral cavities of all infants were examined under the same conditions. The chi-square test, Pearson's chi-square test of independence and Mann-Whitney test were used for the statistical evaluation, with P < 0.05 considered statistically significant. Relative risk (RR) and 95% confidence interval (CI) estimates for variables significantly associated with oral findings were calculated. Results. Both perinatal variables (gestational age, mode of delivery, birthweight, Apgar score, resuscitation, orotracheal intubation and presence of intraoral pathology) and neonatal variables (antibiotic treatment and infections) had a significant association with prematurity, VLBW and ELBW. The one-year-old preterm VLBW and ELBW infants frequently suffered from general diseases, frequently received regular medication and had fewer erupted primary teeth; they also had a higher prevalence of developmental defects of the enamel and deformations of the hard palate. Conclusion. This study confirmed anamnestic, medical and oral differences between one-year-old preterm VLBW and ELBW and full-term NBW infants

Time-domain photocurrent spectroscopy based on a common-path birefringent interferometer

We present diffraction-limited photocurrent (PC) microscopy in the visible spectral range based on broadband excitation and an inherently phase-stable common-path interferometer. The excellent path-length stability guarantees high accuracy without the need for active feedback or post-processing of the interferograms. We illustrate the capabilities of the setup by recording PC spectra of a bulk GaAs device and compare the results to optical transmission data

A Monolithic Hybrid Cellulose-2.5-Acetate/Polymer Bioreactor for Biocatalysis under Continuous Liquid-Liquid Conditions Using a Supported Ionic Liquid Phase

Mesoporous monolithic hybrid cellulose-2.5-acetate (CA)/polymer supports were prepared under solvent-induced phase separation conditions using cellulose-2.5-acetate microbeads 8-14μm in diameter, 1,1,1-tris(hydroxymethyl)propane and 4,4′-methylenebis(phenylisocyanate) as monomers as well as THF and n-heptane as porogenic solvents. 4-(Dimethylamino)pyridine and dibutyltin dilaurate (DBTDL), respectively, were used as catalysts. Monolithic hybrid supports were used in transesterification reactions of vinyl butyrate with 1-butanol under continuous, supported ionic liquid-liquid conditions with Candida antarctica lipaseB (CALB) and octylmethylimidazolium tetrafluoroborate ([OMIM+][BF4-]) immobilized within the CA beads inside the polymeric monolithic framework and methyl tert-butyl ether (MTBE) as the continuous phase. The new hybrid bioreactors were successfully used in dimensions up to 2×30cm (V=94mL). Under continuous biphasic liquid-liquid conditions a constant conversion up to 96% was achieved over a period of 18days, resulting in a productivity of 58μmolmg-1(CALB)min-1. This translates into an unprecedented turnover number (TON) of 3.9×107 within two weeks, which is much higher than the one obtained under standard biphasic conditions using [OMIM+][BF4-]/MTBE (TON=2.7×106). The continuous liquid-liquid setup based on a hybrid reactor presented here is strongly believed to be applicable to many other enzyme-catalyzed reactions.</p

Oral presentation of paraneoplastic pemphigus as the first sign of tonsillar HPV associated squamous cell carcinoma. A case report.

Background. Paraneoplastic pemphigus (PNP) in the oral cavity is a rare variant of blistering pemphigus disease closely associated with mostly malignant tumors. The diagnosis may even precede an underlying malignancy enabling early detection. Here, we describe a previously unreported case of PNP associated with HPV-related tonsillar squamous cell carcinoma. Methods and Results. A 50-year-old woman was referred to a dentist because of painful oral lesions resembling aphthae major and minor. Later, blisters appeared and an incisional biopsy was performed. Histological examination revealed an unusual coexistence of subepithelial and intraepithelial blisters raising suspicion of paraneoplastic pemphigus. The patient underwent 18F-FDG PET/MRI, showing a metabolically active process in the left palatal tonsil. Diagnostic biopsy revealed HPV type 16 associated tonsillar squamous cell carcinoma. A left tonsillectomy with elective left-sided neck dissection was performed. The postoperative period was complicated by bilateral fluidothorax. Two weeks after radical tumor removal, the mucosal and skin lesions of PNP disappeared. The patient currently shows no evidence of recurrence either of malignancy or PNP eight months after the surgery. Conclusion. PNP is a rare autoimmune blistering disease characterized by polymorphous cutaneous and mucosal lesions associated with internal neoplasms including HPV associated squamous cell carcinoma of a tonsil. In order to identify an occult malignancy, a whole-body PET/CT or PET/MRI scan is recommended. Rarely, accurate patient management may depend on the dentist being familiar with this entity and on interdisciplinary cooperation involving dermatologist, radiologist, pathologist, and pneumologist. A strict patient follow-up is indicated

How Frost Forms and Grows on Lubricated Micro- and Nanostructured Surfaces

Frost is ubiquitously observed in nature whenever warmer and more humid air encounters colder than melting point surfaces (e.g., morning dew frosting). However, frost formation is problematic as it damages infrastructure, roads, crops, and the efficient operation of industrial equipment (i.e., heat exchangers, cooling fins). While lubricant-infused surfaces offer promising antifrosting properties, underlying mechanisms of frost formation and its consequential effect on frost-to-surface dynamics remain elusive. Here, we monitor the dynamics of condensation frosting on micro- and hierarchically structured surfaces (the latter combines micro- with nano- features) infused with lubricant, temporally and spatially resolved using laser scanning confocal microscopy. The growth dynamics of water droplets differs for micro- and hierarchically structured surfaces, by hindered drop coalescence on the hierarchical ones. However, the growth and propagation of frost dendrites follow the same scaling on both surface types. Frost propagation is accompanied by a reorganization of the lubricant thin film. We numerically quantify the experimentally observed flow profile using an asymptotic long-wave model. Our results reveal that lubricant reorganization is governed by two distinct driving mechanisms, namely: (1) frost propagation speed and (2) frost dendrite morphology. These in-depth insights into the coupling between lubricant flow and frost formation/propagation enable an improved control over frosting by adjusting the design and features of the surface.publishedVersionPeer reviewe

Metaverse and Medical Diagnosis: A Blockchain-Based Digital Twinning Approach Based on MobileNetV2 Algorithm for Cervical Vertebral Maturation

Advanced mathematical and deep learning (DL) algorithms have recently played a crucial role in diagnosing medical parameters and diseases. One of these areas that need to be more focused on is dentistry. This is why creating digital twins of dental issues in the metaverse is a practical and effective technique to benefit from the immersive characteristics of this technology and adapt the real world of dentistry to the virtual world. These technologies can create virtual facilities and environments for patients, physicians, and researchers to access a variety of medical services. Experiencing an immersive interaction between doctors and patients can be another considerable advantage of these technologies, which can dramatically improve the efficiency of the healthcare system. In addition, offering these amenities through a blockchain system enhances reliability, safety, openness, and the ability to trace data exchange. It also brings about cost savings through improved efficiencies. In this paper, a digital twin of cervical vertebral maturation (CVM), which is a critical factor in a wide range of dental surgery, within a blockchain-based metaverse platform is designed and implemented. A DL method has been used to create an automated diagnosis process for the upcoming CVM images in the proposed platform. This method includes MobileNetV2, a mobile architecture that improves the performance of mobile models in multiple tasks and benchmarks. The proposed technique of digital twinning is simple, fast, and suitable for physicians and medical specialists, as well as for adapting to the Internet of Medical Things (IoMT) due to its low latency and computing costs. One of the important contributions of the current study is to use of DL-based computer vision as a real-time measurement method so that the proposed digital twin does not require additional sensors. Furthermore, a comprehensive conceptual framework for creating digital twins of CVM based on MobileNetV2 within a blockchain ecosystem has been designed and implemented, showing the applicability and suitability of the introduced approach. The high performance of the proposed model on a collected small dataset demonstrates that low-cost deep learning can be used for diagnosis, anomaly detection, better design, and many more applications of the upcoming digital representations. In addition, this study shows how digital twins can be performed and developed for dental issues with the lowest hardware infrastructures, reducing the costs of diagnosis and treatment for patients