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Abstract The count of mitotic figures (MFs) observed in hematoxylin and eosin (H&E)-stained slides is an important prognostic marker, as it is a measure for tumor cell proliferation. However, the identification of MFs has a known low inter-rater agreement. In a computer-aided setting, deep learning algorithms can help to mitigate this, but they require large amounts of annotated data for training and validation. Furthermore, label noise introduced during the annotation process may impede the algorithms’ performance. Unlike H&E, where identification of MFs is based mainly on morphological features, the mitosis-specific antibody phospho-histone H3 (PHH3) specifically highlights MFs. Counting MFs on slides stained against PHH3 leads to higher agreement among raters and has therefore recently been used as a ground truth for the annotation of MFs in H&E. However, as PHH3 facilitates the recognition of cells indistinguishable from H&E staining alone, the use of this ground truth could potentially introduce an interpretation shift and even label noise into the H&E-related dataset, impacting model performance. This study analyzes the impact of PHH3-assisted MF annotation on inter-rater reliability and object level agreement through an extensive multi-rater experiment. Subsequently, MF detectors, including a novel dual-stain detector, were evaluated on the resulting datasets to investigate the influence of PHH3-assisted labeling on the models’ performance. We found that the annotators’ object-level agreement significantly increased when using PHH3-assisted labeling (F1: 0.53 to 0.74). However, this enhancement in label consistency did not translate to improved performance for H&E-based detectors, neither during the training phase nor the evaluation phase. Conversely, the dual-stain detector was able to benefit from the higher consistency. This reveals an information mismatch between the H&E and PHH3-stained images as the cause of this effect, which renders PHH3-assisted annotations not well-aligned for use with H&E-based detectors. Based on our findings, we propose an improved PHH3-assisted labeling procedure.

Abstract Background Hip fracture is very common and it has life-shattering consequences for older persons. After discharge the older persons need help with even basic everyday activities from formal and informal caregivers. In Scandinavia formal care are well-developed however the presence of informal caregivers likely reflect on the amount of formal care and wears on the informal caregivers. This study explore how often and how much informal care (IC) older persons receive after hip fracture. Method We contacted 244 community-dwelling older persons every two weeks the first twelve weeks after discharge after hip fracture and asked them if they received care from family and/or friends and how much. We used non-parametric statistics and level of significance was 95%. Results The proportion of older persons receiving IC was 90% and the median amount of IC was 32 hours (IQR 14-66). The number of older persons who received IC was highest the first four weeks after discharge and so was the amount of hours of IC. The older persons that were high-dependence on IC received a median of 66 (IQR 46-107) hours compared to the low-dependent of 11 hours (IQR 2-20). Conclusion IC is very frequent, especially the first two to four weeks after discharge. The median IC was 32 hours from discharge to the 12-week follow-up. However, this figure tended to rise for persons with, among other, reduced functionality and those residing with a partner. Implications With respect to local differences, the findings in this study are likely applicable to other Scandinavian countries. We strongly suggest that the variation in older person need for informal caregiver be given consideration in the prioritisation of resources. Trial registration This prospective cohort study of informal care, was part of a cluster-randomised stepped-wedge clinical controlled trial. Written consent was obtained required by regional ethics committee S-20200070. Data was collected in accordance with the Danish Data Protection Agency (20-21854).

Abstract The prognostic value of mitotic figures in tumor tissue is well-established for many tumor types and automating this task is of high research interest. However, especially deep learning-based methods face performance deterioration in the presence of domain shifts, which may arise from different tumor types, slide preparation and digitization devices. We introduce the MIDOG++ dataset, an extension of the MIDOG 2021 and 2022 challenge datasets. We provide region of interest images from 503 histological specimens of seven different tumor types with variable morphology with in total labels for 11,937 mitotic figures: breast carcinoma, lung carcinoma, lymphosarcoma, neuroendocrine tumor, cutaneous mast cell tumor, cutaneous melanoma, and (sub)cutaneous soft tissue sarcoma. The specimens were processed in several laboratories utilizing diverse scanners. We evaluated the extent of the domain shift by using state-of-the-art approaches, observing notable differences in single-domain training. In a leave-one-domain-out setting, generalizability improved considerably. This mitotic figure dataset is the first that incorporates a wide domain shift based on different tumor types, laboratories, whole slide image scanners, and species.

BackgroundDigitally supported self-management tailored to an individual’s need, in addition to usual care, may reduce pain-related disability compared to usual care alone, and patients with low back pain (LBP) using mobile health (mHealth) solutions express positive experiences. Hence, implementing mHealth solutions designed to support self-management is desirable from a clinical and patient perspective. Easily accessible mHealth solutions that can support the self-management of patients with LBP are available, but interest may be subgroup specific. Understanding the characteristics and preferences of patients with LBP labeled as interested may help to reach relevant LBP patient groups and inform the development and implementation of effective interventions with mHealth for patients with LBP. ObjectiveThis study aims to explore the proportion of patients with LBP labeled as interested in testing an mHealth solution designed to support self-management in addition to usual care and to assess how these patients differ from those who were labeled as not interested. MethodsThis exploratory cross-sectional study analyzed demographic and patient-reported outcomes from the SpineData registry, a Danish registry of patients with LBP in an outpatient setting. Between February and December 2019, the SpineData registry was used to assess the preliminary eligibility of patients for a clinical trial (selfBACK). Patients were labeled as interested or uninterested depending on if they responded to an invitation to be tested for eligibility for the trial Outcomes were selected from the International Classification of Functioning core set of LBP using a clinical approach. Associations were assessed in a backward selection process, and the proportion of variance explained was assessed with pseudo-R2 statistic. ResultsThis study included 843 patients, with 181 (21%) individuals labeled as interested in participating in the selfBACK trial. Notably, the cohort labeled as interested differed from their uninterested counterparts in two key aspects: age (36-65 years: 116/181, 64.1% vs 347/662, 52.4%; P=.003) and smoking status (smokers: 22/181, 12.5% vs 174/662, 26.6%; P

Abstract Background A hip fracture is a serious event for older adults, given that approximately 50% do not regain their habitual level of physical function, and the mortality rate is high, as is the number of readmissions. The gap in healthcare delivery, as separated into two financial and self-governing sectors, might be a contributing cause of inferior rehabilitation and care for these patients. Therefore, we aim to assess the effect of continuous and progressive rehabilitation and care across sectors for older adults after hip fracture. Methods/design The project is designed as a stepped-wedge cluster randomised controlled trial. The study population of patients are older adults 65 years of age and above discharged after a hip fracture and healthcare professionals in primary and secondary care (municipalities and hospitals). Healthcare professionals from different sectors (hospital and municipalities) will be engaged in the empowerment-orientated praxis, through a workshop for healthcare professionals with knowledge sharing to the older adults using a digital health application (app). The rehabilitation intervention consists of 12 weeks of progressive resistance exercises initiated 1–2 days after discharge. To improve communication across sectors, a videoconference involving the patient and physiotherapists from both sectors will be conducted. On day, 3 after discharge, an outreach nurse performs a thorough assessment including measurement of vital signs. A hotline to the hospital for medical advice is a part of the intervention. The intervention is delivered as an add-on to the usual rehabilitation and care, and it involves one regional hospital and the municipalities within the catchment area of the hospital. The primary outcome is a Timed Up and Go Test 8 weeks post-surgery. Discussion Using a stepped-wedge design, the intervention will be assessed as well as implemented in hospital and municipalities, hopefully for the benefit of older adults after hip fracture. Furthermore, the collaboration between the sectors is expected to improve. Trial registration The study is approved by the Regional Scientific Ethics Committees of Southern Denmark (S-20200070) and the Danish Data Protection Agency (20-21854). Registered 9 of June 2020 at ClinicalTrials.gov, NCT04424186 .

In this overview, the latest achievements in dietary origins, absorption mechanism, bioavailability assay, health advantages, cutting-edge encapsulation techniques, fortification approaches, and innovative highly sensitive sensor-based detection methods of vitamin B12 (VB12) were addressed. The cobalt-centered vitamin B is mainly found in animal products, posing challenges for strict vegetarians and vegans. Its bioavailability is highly influenced by intrinsic factor, absorption in the ileum, and liver reabsorption. VB12 mainly contributes to blood cell synthesis, cognitive function, and cardiovascular health, and potentially reduces anemia and optic neuropathy. Microencapsulation techniques improve the stability and controlled release of VB12. Co-microencapsulation of VB12 with other vitamins and bioactive compounds enhances bioavailability and controlled release, providing versatile initiatives for improving bio-functionality. Nanotechnology, including nanovesicles, nanoemulsions, and nanoparticles can enhance the delivery, stability, and bioavailability of VB12 in diverse applications, ranging from antimicrobial agents to skincare and oral insulin delivery. Staple food fortification with encapsulated and free VB12 emerges as a prominent strategy to combat deficiency and promote nutritional value. Biosensing technologies, such as electrochemical and optical biosensors, offer rapid, portable, and sensitive VB12 assessment. Carbon dot-based fluorescent nanosensors, nanocluster-based fluorescent probes, and electrochemical sensors show promise for precise detection, especially in pharmaceutical and biomedical applications.

Abstract Driving a car requires high cognitive demands, from sustained attention to perception and action planning. Recent research investigated the neural processes reflecting the planning of driving actions, aiming to better understand the factors leading to driving errors and to devise methodologies to anticipate and prevent such errors by monitoring the driver’s cognitive state and intention. While such anticipation was shown for discrete driving actions, such as emergency braking, there is no evidence for robust neural signatures of continuous action planning. This study aims to fill this gap by investigating continuous steering actions during a driving task in a car simulator with multimodal recordings of behavioural and electroencephalography (EEG) signals. System identification is used to assess whether robust neurophysiological signatures emerge before steering actions. Linear decoding models are then used to determine whether such cortical signals can predict continuous steering actions with progressively longer anticipation. Results point to significant EEG signatures of continuous action planning. Such neural signals show consistent dynamics across participants for anticipations up to 1 s, while individual-subject neural activity could reliably decode steering actions and predict future actions for anticipations up to 1.8 s. Finally, we use canonical correlation analysis to attempt disentangling brain and non-brain contributors to the EEG-based decoding. Our results suggest that low-frequency cortical dynamics are involved in the planning of steering actions and that EEG is sensitive to that neural activity. As a result, we propose a framework to investigate anticipatory neural activity in realistic continuous motor tasks.

Objective: To provide a systematic review of the literature and knowledge base of cost per quality-adjusted life year of physical rehabilitation and care of older persons after hip fracture. Material and methods: A research librarian assisted in searching 9 databases (14 May to 27 May 2021), with exclusion of studies on cognitively impaired or institutionalized individuals. A stepwise selection process was conducted by 2 authors, study quality was assessed using Drummond et al.’s checklist, and comparison between different countries was assessed using Welte et al.’s checklist. Results: Three studies were included, which employed 3 different interventions initiated at 3 different postoperative time-points. One high-quality study demonstrated that comprehensive geriatric assessment was cost-effective compared with coordinated care. The other 2 studies did not find the interventions studied to be cost-effective, and both studies were deemed to be of moderate quality. Conclusion: The body of evidence on the cost-effectiveness of physical rehabilitation and care after hip fracture is limited and heterogeneous, with only 1 high-quality study. Thus, stakeholders perform decision-making with a limited knowledge base of the cost-effectiveness of physical rehabilitation and care. We recommend researchers to assess cost-per-QALY. LAY ABSTRACT Hip fractures have severe consequences for older persons and, after surgery, patients need physical rehabilitation and care to recover. Physical rehabilitation and care vary greatly in terms of effectiveness and cost. It is not known what kind of physical rehabilitation and care contribute most to health relative to their costs. This systematic review provides the first comprehensive description of the cost- effectiveness of physical rehabilitation and care of older persons after hip fracture. Nine databases were searched, and 3 economic evaluation studies were identified. One economic study identified comprehensive geriatric care as cost-effective compared with usual coordinated care. The other two studies consisting of an intervention of additional 10 weeks of physical rehabilitation initiated 4 months after discharge and an intervention physical rehabilitation and nutrient management proved not cost-effective compared to usual rehabilitation and care. In conclusion, the number of studies published in this field is very limited and further research is necessary.

Abstract Neutrophils represent one of the first immune cell types recruited to sites of infection, where they can control pathogens by phagocytosis and cytotoxic mechanisms. Intracellular pathogens such as Leishmania major can hijack neutrophils to establish an efficient infection. However the dynamic interactions of neutrophils with the pathogen and other cells at the site of the infection are incompletely understood. Here, we have investigated the role of Ly6G, a homolog of the human CD177 protein, which has been shown to interact with cell adhesion molecules, and serves as a bona fide marker for neutrophils in mice. We show that Ly6G deficiency decreases the initial infection rate of neutrophils recruited to the site of infection. Although the uptake of L. major by subsequently recruited monocytes was tightly linked with the concomitant uptake of neutrophil material, this process was not altered by Ly6G deficiency of the neutrophils. Instead, we observed by intravital 2-photon microscopy that Ly6G-deficient neutrophils entered the site of infection with delayed initial recruitment kinetics. Thus, we conclude that by promoting neutrophils’ ability to efficiently enter the site of infection, Ly6G contributes to the early engagement of intracellular pathogens by the immune system.

Summary: Neutrophils are specialized innate immune cells known for their ability to fight pathogens. However, the mechanisms of neutrophil trafficking to lymph nodes are not fully clear. Using a murine model of dermal infection with Leishmania parasites, we observe a transient neutrophil influx in draining lymph nodes despite sustained recruitment to the infection site. Cell-tracking experiments, together with intravital two-photon microscopy, indicate that neutrophil recruitment to draining lymph nodes occurs minimally through lymphatics from the infected dermis, but mostly through blood vessels via high endothelial venules. Mechanistically, neutrophils do not respond to IL-1β or macrophage-derived molecules. Instead, they are guided by the C5a-C5aR1 axis, using L-selectin and integrins, to extravasate into the draining lymph node parenchyma. We also report that C5, the C5a precursor, is locally produced in the draining lymph node by lymphatic endothelial cells. Our data establish and detail organ-specific mechanisms of neutrophil trafficking.

Abstract This study aimed at investigating how driver’s mental workload could be assessed during driving, using driving performance as well as electrophysiological and subjective data. Participants had to follow a lead vehicle at a safe and constant distance and to deal with two particular driving events (overtaking and pedestrian occurrence) within two sessions (baseline and experimental) on a driving simulator. Traffic density and time pressure (overtaking event) and time pressure (pedestrian event) were increased in the experimental session in order to induce a higher workload. Participants filled NASA TLX questionnaire after each driving session. Electrophysiological parameters (SCL, ECG), driving performance (SDLP and response to speed change of the lead vehicle: coherence, delay and gain) were analysed after each event in two temporal windows (30 s and 5 min). Results showed that both performance and physiological variables differed as a function of traffic conditions and time pressure. Moreover, while performance variations were systematically observed over a long period (5 min after the events), effects on mean SCL data obtained from experimental session notably differed from baseline values within 30 s after the events. Results are discussed in term of mental workload and suggestions are made about the safety systems that could monitor driver’s mental state.

Nowadays, the growing interest in gathering physiological data and human behavior in everyday life scenarios is paralleled by an increase in wireless devices recording brain and body signals. However, the technical issues that characterize these solutions often limit the full brain-related assessments in real-life scenarios. Here we introduce the Biohub platform, a hardware/software (HW/SW) integrated wearable system for multistream synchronized acquisitions. This system consists of off-the-shelf hardware and state-of-art open-source software components, which are highly integrated into a high-tech low-cost solution, complete, yet easy to use outside conventional labs. It flexibly cooperates with several devices, regardless of the manufacturer, and overcomes the possibly limited resources of recording devices. The Biohub was validated through the characterization of the quality of (i) multistream synchronization, (ii) in-lab electroencephalographic (EEG) recordings compared with a medical-grade high-density device, and (iii) a Brain-Computer-Interface (BCI) in a real driving condition. Results show that this system can reliably acquire multiple data streams with high time accuracy and record standard quality EEG signals, becoming a valid device to be used for advanced ergonomics studies such as driving, telerehabilitation, and occupational safety.

In most cases, the bearing capacity of the pile under natural conditions can be determined by applying static and dynamic pile tests as well as the numerical modelling of a dynamic test. The integrated business problem is employed for calculating vertical displacements. This integral is calculated using the summing method. In the majority of cases, real pile strength capacity can be investigated referring to the adapted means of testing applying the mathematical model that can calculate static or dynamic investigations. The idealized scheme of a pile test is presented including a hammering system and soil properties. Moreover, information on the analysis and work of the scheme is disclosed. The article also describes pile hammering models and the equation for Smith method improved by Edwards, Holloway, Briaud and Trucker, Rieke and Crowser, ”GRL“, including the advantages and disadvantages of the introduced method. Smith realized the mathematical analysis of wave propagation supported by a real hammer-pile-soil scheme by discretic elements interaction. Basing on this for classical one dimensional method of wave propagation (that is programmed in computer program MW87) the code of the computer program was changed by authors of this article. When using a computer program, an algorithm for an integral equation was created. The introduced algorithm was made for counting experimental displacement the growth of which along the pile was analyzed. All obtained results were compared with the engineering method indicating that diff erence in results made less than 2%. Using computer program MW87, a diff erent distribution of shaft friction along the pile was studied when the total shaft friction in all cases was constant, because, the results of numerical modelling disclosed that the shaft friction of the pile in one diameter above the pile’s toe was larger than that in the middle or at the top. The hammer-pile-soil system was analyzed with reference to the impact of the returning wave at the top of the pile. Wave propagation in the pile is vertical: the first wave moves from the top to the bottom of the pile. When the bottom is reached, impact wave returns to the top of the pile. All information about the pile of the returning wave is useful as then we can analyze the integrity and bearing capacity of the pile. All this information received from the returning wave is integrated and later shown in the scheme where we can see all steps of performed operations. This article investigates soil deformations and these deformations in soil influence for a hammering pile. A pile of 0,8 m in diameter and 3 m in height, which is in sand, is an object of investigation in this article. For calculation purposes, the pile is divided into 20 segments. Changes in velocities and displacements of pile segments during analysis are graphically shown. Aft er calculating tests on pile dynamics considering diff erent masses of hammers, falling heights of hammers, contribution of shaft friction and static resistances of the piles, a nomograme for determining static resistance of the pile was made. The article explains how the use of the nomograme determines static resistance of the pile and what data on conducting a pile test are needed. Grunto stiprio, kintančio išilgai polio, įtaka smūgio bangos sklidimui polyje Santrauka Daugeliu atvejų tikroji polio laikomoji galia gali būti nustatyta natūraliomis sąlygomis atlikus polio laikomosios galios statinius arba dinaminius bandymus bei atlikus skaitinį dinaminių bandymų modeliavimą. Pateikiama idealizuota polio bandymo arba kalimo sistema, kuri apima plaktą, kalimo sistemą ir grunto savybes. Nurodoma, kokia informacija reikalinga norint atlikti minėtos sistemos analizę, aprašoma, kaip ši sistema veikia. Pateikta idealizuotos polio bandymo arba kalimo sistemos sprendimo veiksmų seka – vienmatės bangos sklidimo polyje skaičiavimo metodas, užprogramuotas kompiuterinėje programoje MW87, kuri straipsnio autorių buvo pakoreguota. Šiame straipsnyje nagrinėjama skirtingai pasiskirsčiusio grunto stiprio, kintančio išilgai polio, įtaka polio kalimo atsakui, kai visas grunto stipris, kintantis išilgai polio, nekinta, nes, remiantis esant tampriajai stadijai gautais skaitinio modeliavimo rezultatais, nustatyta, kad grunto stipris, kintantis išilgai polio, virš pado vieno polio skersmens intervale yra kur kas didesnis negu per polio vidurį arba jo viršuje. Straipsnyje nagrinėjamas 0,8 m skersmens 3 m ilgio polis, esantis smėlio grunte. Skaičiuojant polis yra išdalintas į 20 baigtinių elementų (segmentų). Grafiškai pavaizduota, kaip, priklausomai nuo laiko intervalų, idealizuotoje polio skaičiuojamojoje schemoje kinta segmentų greičiai ir poslinkiai. Atlikus polio dinaminio bandymo skaičiavimus, kai plakto masės ir suminiai grunto stipriai, kintantys išilgai polio, yra skirtingi,buvo sudaryta nomograma, kuria naudojantis galima nustatyti polio statinį stiprį. Straipsnyje pateikiama, kaip, naudojantis nomograma, nustatyti polio laikomąją galią, kokie polio dinaminio bandymo duomenys tam reikalingi. First Published Online: 16 May 2013 Reikšminiai žodžiai: Smith modelis, grunto stipris, smūgio bangos sklidimas, nomograma

An influence of the end boundary conditions to distribution of stress and strains in a soil specimen during conventional compression triaxial tests is analyzed by the experimental and numerical methods. An evaluation of actual stress state is important when determining the shear strength parameters of soil. These methods are used in this paper to investigate and simulate the contact between the testing equipment and ends of sand specimen during the test. Two different conditions of sample boundaries are analyzed: the first case, when the friction between the sample ends and testing machine is not eliminated (fixed ends); the second case, when the friction between the sample ends and testing machine is eliminated (free ends). The friction is eliminated by allowing the sample base to move freely in any horizontal direction. Simulation results of stress-strain distribution in the sample by using the finite element method show that the shear stress at the contact plane increases for the sample with fixed ends. The stress restricts the displacement of sample ends in the horizontal direction. In the case of free ends the horizontal displacement of sample base occurs. Similar to simulation results have been obtained from the laboratory tests performed with triaxial compression apparatus.

Investigation of the porosity of Klaipėda sand by oedometric test is presented. The Klaipėda sand is typical Baltic see-shore sand consisting of grains the average diameter of which varies from 1.18 mm to 0.3 mm. Variation of the porosity during oedometric compression of the whole mixture of the sand and of three separate fractions were investigated experimentally. Porosity was characterised by the maximal (initial) and minimal (after compression) values of the void ratio. It was proved experimentally that porosity of the sand mixture is practically predicted by the coarse-grained fraction with grain diameters ranging between 1.18 mm and 0.6 mm. The role of microstucture in the densification mechanism is explained by employing the discrete element method simulations. The spherical particles and commercial EDEM code were used for modelling purposes. Discrete element method simulations confirmed generally the macroscopic experimental results and yielded additional data on microscopic behaviour. The non-smooth deformation behaviour was observed during detailed numerical time-history analysis. The detected instabilities are explained by rearrangement of the sand grains.

The triaxial test is a most widely used laboratory method for determining the soil shear strength. It is assumed that a soil sample deforms uniformly during triaxial testing. But one often faces a case when the sample in the triaxial apparatus deforms on the contrary. The non-uniformity can be caused by the end restraining effect, the sample height influence factor, the insufficient drainage, the membrane effect and the sample self-weight factor etc. An analysis of known investigations lead to the following tools that could be employed for reducing an inaccuracy related to the non-uniform stress-strain distribution per soil sample during triaxial testing: reducing the sample height/diameter ratio from 2 to 1, eliminating the friction between the sample ends and the plates. Having not eliminated the above - mentioned influence, factors during the testing procedure the angle of internal friction φ and the cohesion c for the sample of φ ≠ 0 are determined larger than the actual ones. The method for determining the angle of internal friction φ and the cohesion c, when testing the soil sample of height/diameter H/D = 1 is proposed.

According to the currently valid standards, bearing resistance can be calculated applying direct informationalstatistic method which includes probabilistic models of margin of resistance Z = R – E. Probabilistic methods allow to determine the influence of which design condition argument on the uncertainty of margin of bearing resistance is the greatest. That enables to project the directions of further investigations. The greatest influence on the uncertainty of margin of bearing resistance is made by the tangent of angle of internal friction and cohesion. Therefore it is required that these strength parameters should be determined more exactly. This would enable to achieve the economy of materials and labour expenditures for the construction of foundation without decreasing reliability of ground. In order to estimate the soil strength parameters more exactly, some changes in the triaxial test apparatus have been made so that the sample base has been allowed to move freely in the horizontal direction. Several experiments have been carried out by improved triaxial test apparatus. It has been determined that the values of the tangent of angle of internal friction and cohesion have been less by 10,8 % and 43 % respectively for dense sand samples with free horizontal base movement than those determined for samples with restricted horizontal movements of ends (regular ends). Foundation width B calculated according to the parameters of residual shearing strength, determined by usual triaxial test apparatus, is smaller by 23 % than that calculated according to the data obtained in the improved triaxial test apparatus. Reliability index of bearing resistance for a sample with regular ends calculated according to the residual values of soil shearing strength parameters by means of first order probabilistic methods for design approach 3 is β = 4,4.

The article focuses on the method for evaluation of ultimate bearing capacity for a vibratory pile having acceleration data recorded during the tests. The simulation vibratory pile installation test was performed in the testing stand. Accelerations were recorded on the top of the simulation vibratory pile during the test. The static test was performed for the installed pile. After the review of rheological models of the base, the Smith rheological model was chosen for determination of bearing capacity of the vibratory pile as this model, the rigidity of the final element of the spring is modelled as the finite rigidity of the base. Between the base of the modelled pile and the soil, a finite interface element is used. The interface element transfers only compression but it does not transfer tension to the base rheological model. The general stiffness of spring's finite element in the chosen rheological model is determined from experimental data of the static pile test. During the modelling, the damping coefficients and the ultimate displacements (responses) of the pile's shaft and base, to which the friction element became active, were determined so that the modelled pile accelerations and displacement (response) would coincide as much as possible with measured accelerations and their calculated response. The modelled and measured accelerations and responses showed high similarity.

Investigation of the compression properties of Klaipėda sand by oedometric testing and numerical modeling is presented. Klaipėda sand is characteristic of the Baltic seashore region sand. Experimental investigation was performed with fraction corresponding to diameter variation bounds of 0.6 and 0.425 mm. Compression test was realized with initial maximal void ratio (e 0 = 0.800) of sand. Employed vertical stress ramp value is 800.0 kPa/min, maximum loading σmax = 400.0 kPa. Applying loading within the range of 50.0 to 120.0, two vertical stress jumps have been identified. A rubber sample compression test has been performed aiming to deny an assumption, that vertical stress jumps are influenced by device construction. Experiment viewed that not any vertical stress jumps have been recognized. Numerical simulation yielded exactly the same two vertical stress jumps found by compression with oedometer. It proves that the nature of rearrangement of sand grains has been properly reflected by modeling compaction process by DEM. Sand compaction velocity is higher versus applied vertical stress ramp. This is the reason for appearing of the vertical stress jumps. Numerical simulation viewed that location of the largest compression in oedometer is at the top of the sample.

The analysis of load distribution in deep foundations found in dense and indiscrete sand between base and shaft is considered in this paper. The availability of designing deep foundations in sand with dilatancy was studied with changing dilatancy angle. For design, Plaxis 3D Foundation v2 MorhCoulomb model was used. Various load distributions between shaft and base were obtained when dilatancy angle varied from 0° to 5°. Skin friction increases significantly increasing dilatancy angle. However, in Mohr-Coulomb model, (drained conditions) soil will continue to dilate as long as shear deformations occurs. This error decreases in case relative foundation length L/D and dilatancy angle ψ decrease. Article in Lithuanian. Giliųjų pamatų modeliavimas taikant Mohr-Coulomb modelį tankiuose smėliuose, esant dilatacijai Anotacija. Straipsnyje nagrinėjamas giliųjų pamatų (standžių gręžtinių ir gręžtinių polių) apkrovos pasiskirstymas tarp pamato pado ir šonų, kai jie yra tankiuose vienalyčiuose smėliuose. Naudojant programinį paketą Plakis 3D Foundation v2, modeliuojama keičiant dilatacijos kampą ir vertinamas Mohr-Coulomb modelio tinkamumas giliųjų pamatų pagrindams modeliuoti. Skirtinguose kampuose yra nevienodas apkrovos pasiskirstymas tarp pado ir šonų, taip pat, didėjant kampui, didėja ir šoninė trintis. Tačiau Mohr-Coulomb grunto modelyje drenuojant grunto tūris didėja tol, kol vyksta skersinės deformacijos. Realiems gruntams tai nėra būdinga, nes dėl tam tikrų įtempių dilatacija nebevyksta. Paklaida mažėja, kai mažėja santykinis giliojo pamato ilgis L/D ir dilatacijos kampas ψ. Reikšminiai žodžiai: polis, gręžtinis pamatas, šoninė trintis, padas, dilatacija, tankus smėlis.

This work presents experimental tests on typical Baltic sea-shore sand along Klaipėda. The paper looks into changes in loaded soil void ratio when using different types of sand fractions in Klaipėda region. Three different types of sand fractions, including 1,18–0,6 mm, 0,6–0,425 mm and 0,425–0,3 mm were analyzed under laboratory conditions. In addition, one mixed sand fraction of diameter 1,18–0,3 mm was created from the equal parts (in mass) of these three different types of sand fractions. Soil usually consists of particles, water and air. An important basic parameter is void ratio e. The soil used under laboratory testing was air drained sand and water influence was not accounted. All tests on soil samples were recorded, because this is the only possible way of investigating the actual displacements versus time changes. Load increments were changed one minute later via the following loading steps: 0; 100; 200; 300; 400; 300; 200; 100; 0 kPa. Almost all displacements reached their final magnitudes in the first 5 seconds when load was increased; when unloaded, it took the first 3 seconds. When porosity is large, soil is called loosely packed. A laboratory test shows that maximum void ratio was in soil with 0,425–0,3 mm particle size where e = 0,840. The lowest maximum void ratio e = 0,714 was obtained for the mixed sand fraction and made 1,18–0,3 mm. The theoretical maximum soil void ratio can be e = 0,910, see Figure 3. This is the loosest packing of spherical particles that seems possible (minimum contact places between particle sizes are 4). Certainly, it is not stable: any small disturbance will make the assembly collapse. When using a very dense packing of spherical particles and the theoretical minimum soil void ratio of this assembly is e = 0,350, see Figure 4. This seems to be the major packing of a set of spherical particles (maximum contact places between particle sizes are 6). Minimum difference between the theoretical maximum void ratio and laboratory maximum void ratio was 0,07 in soil with particle sizes of 0,425–0,3 mm. Soil never consists of spherical particles and the values calculated above have no real meaning for actual soils. They may give a certain indication of what the void ratio of real soil may be. It can thus be expected that void ratio e may have a value somewhere in the range from 0,350 to 0,910. The results of the investigated sea-shore sand along Klaipėda confirms this statement. For Klaipėda sand, when loading it is better to show results of void ratio versus normal stress in lineral relationship (e = aσz + b), see Figure 10, and, when reloading to use semilogarithmic scale (e = alogσz + b), see Figure 11. In the general outline, one can make a conclusion that sand void ratio e decreases versus an increment in the size of soil fraction. Skirtingų smėlio frakcijų spūdumo tyrimas kompresiniu aparatu Santrauka Straipsnio tikslas – ištirti Baltijos jūros smėlinių gruntų ties Klaipėdos pakrante didžiausius poringumo koeficientus, palyginti atskirų frakcijų spūdumo rezultatus tarpusavyje, išnagrinėti atskirų grunto frakcijų spūdumo kitimą laiko atžvilgiu. Palyginti atskirų smėlio frakcijų tyrimų rezultatus su vienodais kiekiais (pagal masę) sumaišyta smėlio frakcija. Grunto tyrimai atlikti su kompresiniu aparatu, naudojant tokias Baltijos jūros pakrantės ties Klaipėda orasausio smėlio frakcijas: 1,18–0,6 mm, 0,6–0,425 mm, 0,425–0,3 mm, ir vienodais kiekiais (pagal masę) sumaišytą 1,18–0,3 mm frakciją. Išanalizavus skirtingų smėlio frakcijų bandymų duomenis, nustatyta, kad didžiausias poringumo koeficientas e = 0,840 būdingas 0,425–0,3 mm dydžio frakcijai. Didėjant frakcijų dydžiui didžiausias poringumo koeficientas mažėja. Sumaišius smėlio frakciją (1,18–0,3 mm) gauta mažiausia didžiausio poringumo koeficiento reikšmė e = 0,714. First Published Online: 16 May 2013 Reikšminiai žodžiai: gruntas, smėlio frakcijos, spūdumas, poringumo koeficientas, apkrova, laikas, nuosėdis.

The article considers linear half space subjected to the circular load of constant intensity. Point settlement is determined by integrating relation to an infinitesimally small area, as per the Bussinesque solution, for concentrated load. The authors propose to replace an integration technique with a summation technique aiming to reduce computational efforts. The application of the summation techniques developed by the authors and their subsequent employment to develop an engineering method ensures sufficient accuracy for engineering purposes for point settlement evaluation. An attractive feature of the proposed engineering method is its implementation via nomograms ready for fast usage. It is especially convenient for a design process that requires obtaining relatively rapid results for multi-variant geotechnical design situations. A calculation algorithm and computational program have been developed to perform the summation techniques. Thanks to the extensive numerical simulations of settlement evaluations under the developed method, variation in the loading surface radius has also been limited. When applying the engineering method, relative error does not exceed 2% for cases when the ratio of radii from the settlement point being investigated to the centre point of circular loading varies within the interval of 1.5 to 7 times. This degree of accuracy is sufficient for engineering design needs. In practice, this engineering method can be applied in case it is assumed that the circular load of constant intensity is the load that acts on the base at the point of contact between the foundation and the base. The point the settlement of which is calculated is the point of the base or the point at the centre of the foundation. It is recommended to apply the engineering method presented in the article when the distance between adjacent foundations is 10 times less than the diameter of the foundation. When the distance is 10 times more than the diameter, foundations almost do not affect each other. The engineering method is especially useful when differential settlements are being calculated, e.g. the impact of deformation seams on the foundations or the effects of a projected building that will be attached to an existing one. This method can be used for calculating both shallow and deep foundations. When deep foundations are calculated, it is necessary to evaluate the enlargement of the pile base occurring due to friction between the ground and the pile material. Inžinerinis metodas taško nuosėdžiui skaičiuoti nuo gretutinės apskritiminės tolygiai išskirstytos apkrovos Santrauka Tiesiškai deformuojamo puserdvio, apkrauto apskritimine tolygiai išskirstyta apkrova, vertikalieji poslinkiai apskaičiuojami integruojant Businesko sprendinio vertikaliojo poslinkio išraišką apkrautame plote. Šis integralas apskaičiuojamas sumavimo metodu. Darbe pateiktas tiesiškai deformuojamo pagrindo, apkrauto apskritimine tolygiai išskirstyta apkrova, nuosėdžių skaičiavimo metodas yra gana tikslus. Šiuo metodu galima įvertinti puserdvio paviršiaus nuosėdį ne tik nuo apskritiminės tolygiai išskirstytos apkrovos, bet ir nuo kitų, greta esančių apskritiminių tolygiai išskirstytų apkrovų. Inžineriniam metodui realizuoti taikytas sumavimo principas, pakeičiantis tiesioginį integravimą reikiamu tikslumu. Tuo tikslu sukurtas sumavimo algoritmas, jį realizuojanti kompiuterinė programa. Inžinerinis poslinkio skaičiavimo metodas realizuotas laipsnine lygtimi ir jam taikyti patogia naudoti nomogramų forma. Taikant sukurtą inžinerinį metodą atliktas nuosėdžių apskaičiavimo skaitinis modeliavimas. Atlikus skaitinio eksperimento rezultatų analizę, identifikuoti nuosėdžių kitimo dėsningumai. Pasiūlyta analizinė išraiška nuosėdžiams skaičiuoti. Nuosėdžių, apskaičiuotų inžineriniu metodu, santykinė paklaida neviršija 2 %, kai apskritiminės tolygiai išskirstytos apkrovos centro taško atstumo iki taško, kurio skaičiuojamas nuosėdis, santykis su apskritiminės tolygiai išskirstytos apkrovos spinduliu kinta nuo 1,5 iki 7. First Published Online: 16 May 2013 Reikšminiai žodžiai: apkritiminė išskirstytoji apkrova, Bussinesque sprendiniai, sumavimo algoritmas, inžinerinis metodas taško nuosėdžiui skaičiuoti

During the determination of soil strength and compressibility in a laboratory by different apparatus soil is loaded in a different way. It has an influence on stress‐strain distribution in a sample. Some factors are not evaluated during the results interpretation, for example, friction between soil and device metal parts. The finite‐element method analysis also shows that during triaxial, oedometer, shear box tests distribution of stress and strain in the sample is non‐uniform. A special apparatus was designed and used for determining horizontal component of stress in the cross‐section of the sample. It was determined for sands that horizontal component of stress in the cross‐section centre is significantly smaller than at the edges. Increasing load plastic deformations are developing not in the whole sample but in particular places. If we know a real distribution of stress and strain in the sample, it is possible to determine the soil strength and deformation parameters in a more precise way or to rate the influence of different factors on soil properties. Santrauka Tiriant gruntų mechanines savybes laboratorijoje kiekviename aparate bandinys apkraunamas skirtingai. Tai turi įtakos įtempimų ir deformacijų pasiskirstymui bandinyje. Interpretuojant bandymo duomenis ignoruojami kai kurie veiksniai, turintys įtaką įtempimams pasiskirstyti, pvz., bandinio galinių plokštumų ir štampo trinties jėgos tiriant gruntą triašio slėgio aparate, bandinio ir žiedo trinties jėgos tiriant gruntą odometre ar tiesioginio kirpimo aparate. Įtempimų pasiskirstymo skaitiniu modeliavimu nustatyta, kad ne tik odometre bei tiesioginio kirpimo aparate, bet ir triašio slėgio aparate bandinio įtempimo būvis nėra vienodas. Sukonstruotas prietaisas, kuriuo galima įvertinti įtempimų horizontaliosios komponentės kitimą bandinio skerspjūvyje. Tiriant smėlinį gruntą gauta, kad įtempimų horizontaliosios komponentės reikšmė bandinio centre yra gerokai mažesnė nei taškuose arti šoninio paviršiaus. Plastinių deformacijų didinant apkrovą atsiras ne visame bandinyje, o tik tam tikruose jo taškuose. Žinant tikrąjį įtempimų ir deformacijų pasiskirstymą bandinyje, bus galima tiksliau nustatyti grunto mechaninių savybių rodiklius arba įvertinti tam tikrų veiksnių įtaką grunto savybių rodikliams. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: įtempimų ir deformacijų pasiskirstymas, triašio slėgio aparatas, odometras, tiesioginio kirpimo aparatas, skaitinis modeliavimas, grunto mechaninių savybių rodikliai.

Designing foundations by soil safety factors is used for obtaining soil strength design values. The methods [10, 11, 12, 13] used for their calculations and minimal values of investigated coefficients are provided in the standards. The design values of soil characteristics computed by different methods do not match. In reality they should ensure the unique reliability of soil shear strength design values. In the present work, the soil shear strength values are computed by different methods. The experimental data are obtained for sands using direct shear strength apparatus. The comparative analysis of obtained results and methods for predicting the design values of soil strength characteristics is applied. When designing foundations, the relation between soil shear strength and normal stress is treated as linear (1, 2), but the dependency of the lower control limit on normal stress is nonlinear (5). Therefore, methods for getting experimental data of soil shear strength give different results. In corresponding standards, different additional conditions are considered for approximation of the investigated non-linear dependency to the linear one. The soil safety factors used for computing design values of tangent of internal friction angle and cohesion depend on these additional conditions. The approximation of non-linear dependency to the linear one does not allow ensuring the unique probability of soil shear strength design values. It is impossible to ensure the desired unique probability for different values of normal stress using traditional methods and constant soil safety factors. In order to obtain the same probability for soil shear strength values lower than the designed value, the probability-statistical methods should be applied. In this article, the method for determining soil shear strength design values is presented (10, 11). This method ensures the same probability of the soil shear strength design values for any values of normal stress. The probability-statistical methods should be applied for design of foundations when soil strength design values depend on normal stress. In order to apply the investigated methods, the probability of foundation collapse or reliability index β, the mean values of soil strength and their variance should be known. Dimensions of the foundation are obtained from mean value sand variance of soil strength characteristics solving the system of equations (13). The solution of this system is a combination of arguments of foundation design conditions that are investigated as normal random variable. The investigated combination corresponds to the limit state. First Published Online: 26 Jul 2012

Kuriant automatizuoto projektavimo sistemas ypač svarbu atkreipti dėmesį į tą. duomenų bei informacijos dalį, kuri dėl jai būdingų savitumų negali būti unifikuota. Ryškiausias pavyzdys šiuo požiūriu galėtų būti inžinerinėsgeologinės sąlygos, kurios įvairiuose pasaulio regionuose yra gana skirtingos. Pasitaiko ir taip, kad dėl to gali skirtis net pati gruntų klasifikacija. Panaši situacija yra ir Lietuvos teritorijoje, kur kai kurių grunto tipų spektras pasirodė platesnis, negu numato kitų valstybių gruntų klasifikacijos sistemos. Jau vien dėl šios priežasties kitose šalyse sukurtos programinės priemonės čia negali būti naudojamos neatlikus tam tikrų pakeitimų bei papildymų. Ne mažiau reikšminga ir kita aplinkybė, apimanti tradiciškai Lietuvoje susiklosčiusius pagrindų ir pamatų projektavimo principus, kurų neturi kitos šalys, kalbant, pavyzdžiui, apie gręžininių pamatų projektavimą ir statybą. Formuluojant patį automatizuoto projektavimo uždavinį, autorių nuomone, pirmiausia reikėtų sujungti iki šiol visiškai atskirtas inžinerinių tyrinėjimų, pagrindų ir pamatų projektavimo, statybos bei eksploatacijos sritis. Kitaip sakant, reikėtų orientuotis į tai, kad ateityje visus tyrinėjimų, projektavimo bei statybos darbus turėtų atlikti viena organizacija, išskiriant nebent inžinerinių tyrinėjimų dalį projekto techninio-ekonominio pagrindimo stadijoje, kai galėtų dirbti šioje srityje besispecializuojančios organizacijos. Tyrinėjimų apimtis šioje stadijoje turėtų būti bent jau tokia, kad iš gautos medžiagos matytųsi, koks pamatų tipas labiausiai tinka konkrečioms gruntinėms sąlygoms. Tada projekto darbo brėžinių stadijoje tyrinėti turėtų jau pati pamatų statybos darbus atliekanti organizacija. Šitaip nulinio ciklo projektavimo bei statybos darbai vyktų kompleksiškai ir vienu metu, pagal principą “nuo stalo į gamybą”. Pamatų automatizuoto projektavimo diegimo būdai gali būti labai įvairūs ir pirmiausia priklauso nuo to, kokios projektavimo sistemos bus laikomasi kiekvienu konkrečiu atveju. Atsižvelgiant į mūsų dabarties galimybes, šiam tikslui visai neblogai gali būti naudojami plačiai žinomi ir labiausiai prieinami CAD sistemoje bei jos terpėje dirbantys programų paketai. Antra vertus, nemažai projektavimo uždavinių galima išspręsti ir savo jėgomis. Darbe parodyta, kaip remiantis matematinės statistikos dėsniais gali būti analitiškai nustatomos pagrindo sluoksnių ribos. Be šio klausimo, yra išspręstas, tik netilpęs į šio straipsnio rėmus, ir vienas svarbiausių projektavimo uždavinių—pagrindo normuotam patikimumui skaičiuoti. Dabartiniu metu dirbama ties pagrindo skaitmeninio modelio sukūrimo problema. Visi šie, o ir kiti panašūs geotechnikos problemų sprendimo būdai, vadovaujantis išdėstytais automatizuotos projektavimo sistemos kūrimo principais, neabejotinai gali sudaryti atskiras šios sistemos grandis. First Published Online: 26 Jul 2012

Iš žinomų pamatų tipų pamato konstrukcijos stiprumas efektyviausiai naudojamas parenkant tuščiavidurius, vadinamuosius kevalinius pamatus, dažniausiai žiedinio skerspjūvio, cilindro arba kūgio formos. Tačiau šį privalumą, kaip taisyklė, menkina neracionali tokių pamatų gamybos bei įrengimo technologija. Darbe apsistota ties melioracijoje plačiai naudotais gelžbetoniniais beslėgiais vamzdžiais, kurių poreikis pastaruoju metu gerokai sumažėjęs. Jų cilindro forma leidžia šiai vamzdinei konstrukcijai taikyti pagrindinį gręžininių pamatų technologijos pranašumą, kurio dėka pamato pado projektinė altitudė pasiekiama ne tradiciniu kasimu, bet gręžimu. Šiuo atveju gelžbetoniniai vamzdžiai būtų įstatomi į šiek tiek didesnio skersmens gręžinius. Susidariusį tarpą, tarp pamato ir gręžinio sienučių būtina užpildyti tuo pačiu, tačiau sutankintu gruntu. Autorių įsitikinimu, viršutinėje pamato dalyje įrengus gelžbetoninę pagalvę, visą kitą vidinę pamato dalį pakanka užpildyti paprasčiausiu gerai sutankintu smęliu, vietoj seniau naudoto prekinio betono. Patentinė paieška parodė, kad toks būdas statybos praktikoje dar netaikytas. Lyginant su gręžininiais pamatais, šiuo metodu betono sutaupoma 3 ir daugiau kartų, o gamybos bei įrengimo išlaidų—iki 2 kartų. Tokio tipo kevaliniai pamatai, galbūt net vadintini vamzdiniais, taptų dar efektyvesniais, jeigu iki projektinės padėties būtų gramzdinami kalamuoju arba vibraciniu būdu. Straipsnyje paliesti naujos pamatų konstrukcijos taikymo, projektavimo bei tyrimo klausimai. Parodoma, kad pamato apkrovimo momento reikšmė labai priklauso nuo pasirinktos skaičiuojamosios schemos, pagal kurią pamato sujungimas su antžeminėmis konstrukcijomis gali būti laisvasis arba standusis. Kaip rodo skaičiavimo rezultatai, standžiojo sujungimo atveju pamato viršutinės dalies poslinkis bei posūkis sumažėja iki 2, o maksimalus lenkimo momentas—net iki 4 kartų. Aptariami ir kiti šių pamatų projektavimo ypatumai bei tolesnių tyrimų kryptys. First Published Online: 26 Jul 2012

Six different flexible stereocontrolled oligo(triazole-urethane)s substituted by precise sequences of nucleobases or analogs are synthesized. Molecular dynamics simulations indicate that the flexibility of the backbone leads to unspecific complexation of pairs of oligomers, irrespective of the complementarity of their sequences. This is ascribed to the existence of other interactions between pairs of oligomers, as well as to the spatial blurring of the sequence order encoded in the chemical structure of the chain due to its flexibility. The same conclusions are drawn when investigating the irreversible adsorption of different probe oligomers onto a layer of target oligomers grafted by click chemistry in a mushroom configuration on a silicon substrate. In contrast, when the target oligomers are grafted in denser brush configurations, irreversible adsorption becomes more specific, with it being twice as probable that probe chains of complementary sequence would be irreversibly-bound to the layer of target chains than those of non-complementary sequence. This is ascribed to lateral excluded volume interactions between chains in the brush, leading to partial chain stretching and increased spatial preservation of the information contained in the monomer sequence of the chains. At even higher grafting densities, however, the penetration of the probe chains in the brush becomes increasingly difficult, resulting in a loss of binding efficiency. Our work thus demonstrates the adverse role of chain flexibility in the specificity of complexation between nucleobase-functionalized oligomers and provides directions for an improvement of specificity by tuning the grafting density of target chains on a substrate.

Here, we report on the synthesis of discrete oligomers of alkyl-bridged naphthalenediimides (NDIs) and study their molecular nanostructures both in bulk, in solution, and at the liquid-solid interface. Via an iterative synthesis method, multiple NDI cores were bridged with short and saturated alkyl-diamines (C 3 and C 12 ) or long and unsaturated alkyl-diamines (u 2 C 33 to u 8 C 100 ) at their imide termini. The strong intermolecular interaction between the NDI cores was observed by probing their photophysical properties in solution. In bulk, the discrete NDI oligomers preferentially ordered in lamellar morphologies, irrespective of whether a saturated or unsaturated spacer was employed. Moreover, both the molecular architecture as well as the crystallization conditions play a significant role in the nanoscale ordering. The long unsaturated alkyl chains lead preferably to folded-chain conformations while their saturated analogues form stretched arrangements. At the solution-solid interface, well-defined lamellar regions were observed. These results show that precision in chemical structure alone is not sufficient to reach well-defined structures of discrete oligomers, but that it must be combined with precision in processing conditions., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

We show the emergence of strong catalytic activity at low concentrations in dynamic libraries of complementary sequence-defined oligomeric chains comprising pendant functional catalytic groups and terminal recognition units. In solution, the dynamic constitutional library created from pairs of such complementary oligomers comprises free oligomers, self-assembled di(oligomeric) macrocycles, and a virtually infinite collection of linear poly(oligomeric) chains. We demonstrate, on an exemplary catalytic system requiring the cooperation of no less than five chemical groups, that supramolecular di(oligomeric) macrocycles exhibit a catalytic turnover frequency ca. 20 times larger than the whole collection of linear poly(oligomers) and free chains. Molecular dynamics simulations and network analysis indicate that self-assembled supramolecular di(oligomeric) macrocycles are stabilized by different interactions, among which chain end pairing. We mathematically model the catalytic properties of such complex dynamic libraries with a small set of physically relevant parameters, which provides guidelines for the synthesis of oligomers capable to self-assemble into functionally-active supramolecular macrocycles over a larger range of concentrations., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Similar to biological macromolecules such as DNA and proteins, the precise control over the monomer position in sequence-defined polymers is of paramount importance for tuning their structures and properties toward achieving specific functions. Here, we apply molecular network analysis on three-dimensional structures issued from molecular dynamics simulations to decipher how the chain organization of trifunctional catalytic oligomers is influenced by the oligomer sequence and the length of oligo(ethylene oxide) spacers. Our findings demonstrate that the tuning of their primary structures is crucial for favoring cooperative interactions between the catalytic units and thus higher catalytic activities. This combined approach can assist in establishing structure-property relationships, leading to a more rational design of sequence-defined catalytic oligomers via computational chemistry.

Layer-by-layer (LbL) assembly is a versatile technology to construct multifunctional nanomaterials using various supporting substrates, enabled by the large selection freedom of building materials and diversity of possible driving forces. The fine regulation over the film thickness and structure provides an elegant way to tune the physical/chemical properties by mild assembly conditions (e.g. pH, ion strength). In this review, we focus on LbL in nanochannels, which exhibit a different growth mechanism compared to "open", convex substrates. The assembly mechanism in nanochannels is discussed in detail, followed by the summary of applications of LbL assemblies liberated from nanochannel templates which can be used as nanoreactors, drug carriers and transporting channels across cell membranes. For fluidic applications, robust membrane substrates are required to keep in place nanotube arrays for membrane-based separation, purification, biosensing and energy harvesting, which are also discussed. The good compatibility of LbL with crossover technologies from other fields allows researchers to further extend this technology to a broader range of research fields, which is expected to result in an increased number of applications of LbL technology in the future.

Imparting hydrophobicity to solid acid catalysts is critical to regulating their performances by allowing the creation of a less polar environment and improved partitioning of the reactants. Here we present different approaches for the preparation of silica-based catalysts comprising sulfonic acid (-SO 3 H) sites and hydrophobic decyl (-C 10 ) chains by either simultaneous or sequential postfunctionalization of an azide-functionalized mesoporous silica platform. This set of hybrid bifunctional catalysts is compared in the model esterification of octanol with acetic acid, and the influence of the preparation methods together with the resulting site spatial distribution is discussed. In parallel, we show that pairing the two functional groups affords a maximum synergistic effect compared to more traditional mixed catalysts with random distributions of acid and hydrophobic functions.

Cell culture on microcarriers emerges as an alternative of two-dimensional culture to produce large cell doses, which are required for cell-based therapies. Herein, we report a versatile and easy solvent-free greener fabrication process to prepare microcarriers based on a biosourced and compostable polymer. The preparation of the microcarrier core, which is based on poly(L-lactide) crystallization from a polymer blend, allows us to easily tune the density, porosity, and size of the microparticles. A bioadhesive coating based on biopolymers, devoid of animal protein and optimized to improve cell adhesion, is then successfully deposited on the surface of the microcarriers. The ability of these new microcarriers to expand human adipose-derived stromal cells with good yield, in semistatic and dynamic conditions, is demonstrated. Finally, bead-to-bead cell transfer is shown to increase the yield of cell production without having to stop the culture. These microcarriers are therefore a promising and efficient green alternative to currently existing systems.

Understanding the wetting properties of chemically modified inorganic surfaces with random nanoscale topographies is of fundamental importance for diverse applications. This issue has hitherto continuously been the subject of considerable controversies. Herein, we report a thorough investigation of the wettability-topography-chemistry balance for a nanostructured surface with random topography, the main challenge being decoupling topography from surface chemistry. For this purpose, we use a superficially nanostructured aluminum substrate chemically modified by fatty acid monolayers. From atomic force microscopic data, we extract a variety of parameters describing the surface topography by means of variogram calculations, a method originally developed by geostatisticians to explore large surfaces. Moreover, by using log and power transforms, we establish a consistent relationship relating wettability, topography, and surface chemistry. Interestingly, we demonstrate that the water contact angle comprises a contribution due to the surface composition, originating from hydrophobization through alkyl chains, and a contribution due to the surface topography, particularly its stochastic feature. This model is valid in the Wenzel region; it provides guidelines for tuning the wetting properties of inorganic surfaces with random nanoscale topographies.

The outbreak of vaping-related acute lung injury in the United States, named EVALI (e-cigarette or vaping product use associated acute lung injury), has reignited concerns about the health effects of vaping. Initial case reports of vaping-related lung injury date back to 2012, but the ongoing outbreak of EVALI began in the summer of 2019 and has been implicated in 2,807 cases and 68 deaths as of this writing. Review of the scientific literature revealed 216 patient cases that spanned 41 reports of parenchymal lung injury attributed to vaping. In this review, we detail the clinical, radiographic, and pathologic patterns of lung injury that are attributable to vaping and provide an overview of the scientific literature to date on the effects of vaping on respiratory health. Tetrahydrocannabinol was the most commonly vaped substance, and vitamin E acetate was found in BAL specimens from many affected individuals. However, no specific component or contaminant has been identified conclusively to date as the cause for the injury. Patients present with cough, dyspnea, constitutional symptoms, and GI symptoms. Radiologic and histopathologic findings demonstrate a spectrum of nonspecific acute injury patterns. A high index of suspicion combined with a good history are the keys to an accurate diagnosis. Treatment is supportive; the mortality rate is low, and most patients recover. Corticosteroids have been used with apparent success in patients with severe disease, but more rigorous studies are needed to clarify their role in the treatment of vaping-related lung injury., (Copyright © 2020 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

In addition to mesenchymal stem cells, adipose-derived stem/stromal cells (ASCs) are an attractive source for a large variety of cell-based therapies. One of their most important potential applications is related to the regeneration of bone tissue thanks to their capacity to differentiate in bone cells. However, this requires a proper control of their osteogenic differentiation, which depends not only on the initial characteristics of harvested cells but also on the conditions used for their culture. In this review, we first briefly describe the preclinical and clinical trials using ASCs for bone regeneration and present the quantitative parameters used to characterize the osteogenic differentiation of ASCs. We then focus on the soluble factors influencing the osteogenic differentiation of ACS, including the steroid hormones and various growth factors, notably the most osteoinductive ones, the bone morphogenetic proteins (BMPs). Impact statement Adipose-derived stromal/stem cells are reviewed for their use in bone regeneration.

The development of a functional in vitro model for microcirculation is an unresolved challenge, with major impact for the creation and regeneration of organs in the tissue engineering. The absence of prevascularized engineered tissues limits enormously their efficacy and integration. Therefore, in this study, the in vitro formation of tubular-like structures with human umbilical vein endothelial cells (HUVECs) is investigated thanks to three-dimensional polycarbonate (PC) microchannel (μCh) scaffolds, surface biofunctionalized with hyaluronic acid/chitosan (HA/CHI) layer-by-layer (LbL) films grafted with adhesive (RGD) and angiogenic (SVV and QK) peptides, alone and in combination. The importance of this work lies in the formation of capillaries in the order of tens of μm, developing spontaneous microvessels, without the complexity of microfluidic approaches, and in a short time-scale. Ellipsometry, confocal laser scanning microscopy, and fluorospectrometry are used to characterize the biofunctionalized microchannels. PC-μCh scaffolds functionalized with (HA/CHI) 12.5 film (PC-LbL) and further grafted with RGD and QK peptides (PC-RGD+QK) or with RGD and SVV peptides (PC-RGD+SVV) are then tested for in vitro blood vessel formation. These assays evidence a rapid formation of tubular-like structures after 2 h of incubation. Moreover, a coculture system involving HUVECs and human pericytes derived from placenta (hPCs-PL) stabilizes the tubes for a longer time.

An antioxidant material composed of halloysite nanotubes (HNTs), protamine sulfate polyelectrolyte (PSP), and superoxide dismutase (SOD) enzyme was prepared by self-assembly of the PSP and SOD biomacromolecules on the nanoparticulate support. The structural, colloidal and biocatalytic features were assessed. Adsorption of PSP on the oppositely charged HNT surface at appropriate loadings gave rise to charge neutralization and overcharging, which resulted in unstable and stable dispersions, respectively. The formation of a saturated PSP layer on the HNT led to the development of positive surface charge and to remarkable resistance against salt-induced aggregation making the obtained HNT-PSP hybrid suitable for immobilization of negatively charged SOD. No enzyme leakage was observed from the HNT-PSP-SOD composite indicating sufficient structural stability of this material due to electrostatic, hydrophobic, and hydrogen bonding interactions taking place between the particles and the biomacromolecules. Enzymatic assays revealed that SOD kept its functional integrity upon immobilization and showed high activity in superoxide radical dismutation. In this way, stable antioxidant bionanocomposite dispersions were obtained, which can be used as antioxidants in heterogeneous samples.

We report on a simple and versatile method for the preparation in one-step of omniphobic textiles, using only aqueous suspensions of silica particles and polyurethane devoid of long perfluoroalkyl chains (C8) that are now legally-banned because of severe environmental concerns. The omniphobic coatings can be applied on different substrates including fabrics, can resist acidic and basic conditions and a moderate number of washing cycles, and repel liquids such as n -octane, dodecane, hexadecane, ethylene glycol, glycerol, olive oil, and water. Analysis of the wetting properties of coated fabrics indicates that the liquid repellence results from the trapping of air in the re-entrant roughness created by aggregates of silica particles, together with the low surface tension of the polyurethane which bears legally accepted short perfluoroalkyl chains (C4). Our study is a significant step forward toward achieving more environmentally-friendly and robust omniphobic textiles., Competing Interests: The authors declare no competing financial interest., (Copyright © 2019 American Chemical Society.)

Background: Human adipose-derived stromal cells (hASCs) have been gaining increasing popularity in regenerative medicine thanks to their multipotency, ease of collection, and efficient culture. Similarly to other stromal cells, their function is particularly sensitive to the culture conditions, including the composition of the culture medium. Given the large number of parameters that can play a role in their specification, the rapid assessment would be beneficial to allow the optimization of their culture parameters., Method: Herein we used the design of experiments (DOE) method to rapidly screen the influence and relevance of several culture parameters on the osteogenic differentiation of hASCs. Specifically, seven cell culture parameters were selected for this study based on a literature review. These parameters included the source of hASCs (the different providers having different methods for processing the cells prior to their external use), the source of serum (fetal bovine serum vs. human platelet lysate), and several soluble osteoinductive factors, including dexamethasone and a potent growth factor, the bone morphogenetic protein-9 (BMP-9). The expression of alkaline phosphatase was quantified as a readout for the osteogenic differentiation of hASCs., Results: The DOE analysis enabled to classify the seven studied parameters according to their relative influence on the osteogenic differentiation of hASCs. Notably, the source of serum was found to have a major effect on the osteogenic differentiation of hASCs as well as their origin (different providers) and the presence of L-ascorbate-2-phosphate and BMP-9., Conclusion: The DOE-based screening is a valuable approach for the classification of the impact of several cell culture parameters on the osteogenic differentiation of hASCs.

The development of sturdy enzyme-containing hydrophilic coatings is important for applications such as water purification or biological sensing. Here, we investigate the encapsulation of a model enzyme (beta-lactamase, BlaP) into aluminosilicate halloysite nanotubes (HNTs), and their subsequent use for the fabrication of enzymatic coatings by layer-by-layer (LbL) assembly. Highly stable suspensions of enzymatically-active halloysite nanotubes were obtained by alkaline treatment of HNTs, followed by enzyme adsorption into the lumen of the nanotubes and of poly(ethylene imine) (PEI) onto their outer surface. Bioactive thin films based on the LbL-assembly of these modified nanotubes with negatively-charged alginate provided coatings with a significantly higher enzymatic activity compared to films in which the enzyme is not incorporated in the nanotubes. The obtained results show that the encapsulation of an enzyme in halloysite nanotubes is a viable route towards stable bioactive coatings, which could be easily adapted to entrap other types of biomacromolecules with the aim of preparing thin films for air or effluent decontamination., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Solid acid catalysts are central in our chemical industry and are major players in the valorization of bioresources. However, there is still a need to develop solid acid catalysts with enhanced acid strength and improved, or tunable, physicochemical profile to enhance the efficiency and sustainability of chemical processes. Here, a modular approach to tune the acid strength and surface polarity of silica-supported sulfonic acid catalysts, based on a versatile copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based anchoring scheme, is presented. The CuAAC-formed triazole link was used to enhance the activity of the grafted sulfonic acids and to pair the acid sites with secondary hydrophobic functions. The beneficial effects of both the triazolium link and the paired hydrophobic site, as well as the optimal positioning of the sulfonic moiety on the triazole ring, are discussed in model esterification reactions., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Cooperative catalysis on solid surfaces relies primarily on two or more catalytic partners being close enough to each other to sustain the catalytic cycle. We describe here the synthesis and preliminary investigation of discrete homo-oligomers as flexible scaffolds to inflect the intersite distance and blur the compositional heterogeneity in a silica-grafted catalytic triad., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We demonstrate entrapment of the commensal skin bacteria Staphylococcus epidermidis in mats composed of soft nanotubes made by membrane-templated layer-by-layer (LbL) assembly. When cultured in broth, the resulting nanofibrillar patches efficiently delay the escape of bacteria and their planktonic growth, while displaying high steady-state metabolic activity. Additionally, the material properties and metabolic activity can be further tuned by postprocessing the patches with additional polysaccharide LbL layers. These patches offer a promising methodology for the fabrication of bacterial skin dressings for the treatment of skin dysbiosis while preventing adverse effects due to bacterial proliferation.

Layer-by-layer (LbL) assembly is an attractive method for protein immobilization at interfaces, a much wanted step for biotechnologies and biomedicine. Integrating proteins in LbL thin films is however very challenging due to their low conformational entropy, heterogeneous spatial distribution of charges, and polyampholyte nature. Protein-polyelectrolyte complexes (PPCs) are promising building blocks for LbL construction owing to their standardized charge and polyelectrolyte (PE) corona. In this work, lysozyme was complexed with poly(styrenesulfonate) (PSS) at different ionic strengths and pH values. The PPCs size and electrical properties were investigated, and the forces driving complexation were elucidated, in the light of computations of polyelectrolyte conformation, with a view to further unravel LbL construction mechanisms. Quartz crystal microbalance and atomic force microscopy were used to monitor the integration of PPCs compared to the one of bare protein molecules in LbL assemblies, and colorimetric assays were performed to determine the protein amount in the thin films. Layers built with PPCs show higher protein contents and hydration levels. Very importantly, the results also show that LbL construction with PPCs mainly relies on standard PE-PE interactions, independent of the charge state of the protein, in contrast to classical bare protein assembly with PEs. This considerably simplifies the incorporation of proteins in multilayers, which will be beneficial for biosensing, heterogeneous biocatalysis, biotechnologies, and medical applications that require active proteins at interfaces.

Porous polymeric microcarriers are a versatile class of biomaterial constructs with extensive use in drug delivery, cell culture and tissue engineering. Currently, most methods for their production require potentially toxic organic solvents with complex setups which limit their suitability for biomedical applications and their large-scale production. Herein, we report an organic, solvent-free method for the fabrication of porous poly(l-lactide) (PLLA) microcarriers. The method is based on the spherulitic crystallization of PLLA in its miscible blends with poly(ethylene glycol) (PEG). It is shown that the PLLA spherulites are easily recovered as microcarriers from the blends by a water-based process. Independent control over microcarrier size and porosity is demonstrated, with a higher crystallization temperature leading to a larger size, and a higher PLLA content in the starting blend resulting in a lower microcarrier porosity. Microcarriers are shown to be biocompatible for the culture of murine myoblasts and human adipose stromal/stem cells (hASC). Moreover, they support not only the long-term proliferation of both cell types but also hASC differentiation toward osseous tissues. Furthermore, while no significant differences are observed during cell proliferation on microcarriers of two different porosities, microcarriers of lower porosity induce a stronger hASC osteogenic differentiation, as evidenced by higher ALP enzymatic activity and matrix mineralization. Consequently, the proposed organic-solvent-free method for the fabrication of biocompatible porous PLLA microcarriers represents an innovative methodology for ex vivo cell expansion and its application in stem cell therapy and tissue engineering., Statement of Significance: We report a new solvent-free method for the preparation of porous polymeric microcarriers for cell culture, based on biocompatible poly(l-lactide), with independently controllable size and porosity. This approach, based on the spherulitic crystallization in polymer blends, offers the advantages of simple implementation, biological and environmental safety, easy adaptability and up-scalablility. The suitability of these microcarriers is demonstrated for long-term culture of both murine myoblasts and human adipose stromal/stem cells (hASCs). We show that prepared microcarriers support the osteogenic differentiation of hASCs, provided microcarriers of properly-tuned porosity are used. Hence, this new method is an important addition to the arsenal of microcarrier fabrication techniques, which will contribute to the adoption, regulatory approval and eventually clinical availability of microcarrier-based treatments and therapies., (Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Commensal skin bacteria such as Staphylococcus epidermidis are currently being considered as possible components in skin-care and skin-health products. However, considering the potentially adverse effects of commensal skin bacteria if left free to proliferate, it is crucial to develop methodologies that are capable of maintaining bacteria viability while controlling their proliferation. Here, we encapsulate S. epidermidis in shells of increasing thickness using layer-by-layer assembly, with either a pair of synthetic polyelectrolytes or a pair of oppositely charged polysaccharides. We study the viability of the cells and their delay of growth depending on the composition of the shell, its thickness, the charge of the last deposited layer, and the degree of aggregation of the bacteria which is varied using different coating procedures-among which is a new scalable process that easily leads to large amounts of nonaggregated bacteria. We demonstrate that the growth of bacteria is not controlled by the mechanical properties of the shell but by the bacteriostatic effect of the polyelectrolyte complex, which depends on the shell thickness and charge of its outmost layer, and involves the diffusion of unpaired amine sites through the shell. The lag times of growth are sufficient to prevent proliferation for daily topical applications.

We report on a facile, versatile, and environmentally friendly method to prepare superhydrophobic fabrics by a simple dip-coating method in water-based suspensions and emulsions. All the materials used are fluorine-free and commercially available at a large scale. The method can be easily integrated into standard textile industrial processes and has a strong potential for the mass production of environmentally friendly superwater-repellent fabrics. The produced fabrics show good resistance to machine washing and acidic or alkaline treatments. In addition, it is shown that superhydrophobicity can be quantitatively predicted based on the combination of the roughness of the fabric and of the fiber coating.