Orientation-dependent oxidation behavior of Cu under In-situ E-Beam irradiation

Herein, we present an atomic in-situ investigation of Cu oxidation along different orientations stimulated by high-energy electron beams (E-Beam) in transmission electron microscopy (TEM). By following the microstructural evolution of the Cu substrate in real time, high-resolution TEM (HRTEM) images reveal an orientation-dependent oxidation mechanism, whereby Cu along [110] zone axis migrates onto the surface and be oxidized while Cu along [100] zone axis is oxidized completely both in bulk and at the surface. The different oxidation mechanisms can be attributed to the differing diffusion rates of oxygen in Cu structures along directions. Moreover, the growth of Cu oxides is found to follow a layer-by-layer mechanism, where Cu mostly migrates onto nanocrystal {110} planes. This behavior would lead to the oxides wider in geometric shape and therefore promote the aggregation of adjacent oxides. These findings have important implications for the practical use of copper-based materials in oxidizing environments.

Surface slicing and toolpath planning forin-situbioprinting of skin implants

Bioprinting has emerged as a successful method for fabricating engineered tissue implants, offering great potential for wound healing applications. This study focuses on an advanced surface-based slicing approach aimed at designing a skin implant specifically forin-situbioprinting. The slicing step plays a crucial role in determining the layering arrangement of the tissue during printing. By utilizing surface slicing, a significant shift from planar fabrication methods is achieved. The developed methodology involves the utilization of a customized robotic printer to deliver biomaterials. A multilayer slicing and toolpath generation procedure is presented, enabling the fabrication of skin implants that incorporate the epidermal, dermal, and hypodermal layers. One notable advantage of using the approximate representation of the native wound site surface as the slicing surface is the avoidance of planar printing effects such as staircasing. This surface slicing method allows for the design of non-planar and ultra-thin skin implants, ensuring a higher degree of geometric match between the implant and the wound interface. Furthermore, the proposed methodology demonstrates superior surface quality of thein-situbio-printed implant on a hand model, validating its ability to create toolpaths on implants with complex surfaces.

Fabrication of Silver Iodide (AgI) Patterns via Photolithography and Its Application to In-Situ Observation of Condensation Frosting

This study introduces an innovative photolithography-based method for patterning ionic and inorganic particle materials such as silver iodide (AgI). Conventional methods lack precision when patterning powdered materials, which limits their applicability. The proposed method stacks layers of a particle material (AgI) and negative-tone photoresist for simultaneous ultraviolet exposure and development, resulting in well-defined AgI patterns. The sintering process successfully removed binders from the material layer and photoresist, yielding standalone AgI patterns on the Si substrate with good adhesion. The pitch remained consistent with the design values of the photomask when the pattern size was changed. In-situ observation of condensation frosting on the patterns was conducted, which confirmed the practicality of the developed patterning process. This versatile method is applicable to large areas with a high throughput and presents new opportunities for modifying functional surfaces.

Comparative analysis of patients undergoing lower extremity bypass using in-situ and reversed great saphenous vein graft techniques

OBJECTIVE

Autologous great saphenous vein (GSV) is considered the conduit of choice for lower extremity bypass (LEB). However, the optimal configuration remains the source of debate. We compared outcomes of patients undergoing LEB using in-situ and reversed techniques.

METHODS

The Vascular Quality Initiative database was queried for patients undergoing LEB with a single-segment GSV in in-situ (ISGSV) and reversed (RGSV) configurations for symptomatic occlusive disease from 2003 to 2021. Patient demographics, procedural detail, and in-hospital and follow-up outcomes were collected. The primary outcome measures included primary patency at discharge or 30 days and one year. Secondary outcomes were secondary patency, and reinterventions at discharge or 30 days and one year. Cox proportional hazards models were created to determine the association between bypass techniques and outcomes of interest.

RESULTS

Of 8234 patients undergoing LEBs, in-situ and reversed techniques were used in 3546 and 4688 patients, respectively. The indication for LEBs was similar between the two cohorts. ISGSV was performed more frequently from the common femoral artery and to more distal targets. RGSV bypass was associated with higher intraoperative blood loss and longer operative time. Perioperatively, ISGSV cohort had higher rates of reinterventions (13.2 vs 11.1%; p = 0.004), surgical site infection (4.2 vs 3%; p = 0.003), and lower primary patency (93.5 vs 95%; p = 0.004) but a comparable rate of secondary patency (99 vs 99.1%; p = 0.675). At 1 year, in-situ bypasses had a lower rate of reinterventions (19.4% vs 21.6%; p=0.02), with similar rates of primary (82.6 vs 81.8%; p = 0.237) and secondary patency (88.7 vs 88.9%; p = 0.625). After adjusting for significant baseline differences and potential confounders, in-situ bypass was independently associated with decreased risks of primary patency loss (HR 0.9; 95% CI, 0.82-0.98; p = 0.016) and reinterventions (HR 0.88; 95% CI, 0.8-0.97; p = 0.014) but a similar risk of secondary patency loss (HR 0.99; 95% CI, 0.86-1.16; p = 0.985) at follow-up, compared to reversed bypass. A subgroup analysis of bypasses to crural targets showed that in-situ and reversed bypasses had similar rates of primary patency loss and reinterventions at 1 year. Among patients with chronic limb-threatening ischemia, in-situ bypass was associated with a decreased risk of reinterventions but similar rates of primary and secondary patency and major amputations at 1 year.

CONCLUSIONS

In patients undergoing LEBs using the GSV, in-situ configuration was associated with more perioperative reinterventions and lower primary patency rate. However, this was offset by decreased risks of loss of primary patency and reinterventions at 1 year. A thorough intraoperative graft assessment with adjunctive imaging may be performed to detect abnormalities in patients undergoing in-situ bypasses to prevent early failures. Furthermore, closer surveillance of reversed bypass grafts is warranted given the higher rates of reinterventions.

Acrylate monomer polymerization triggered by iron oxide magnetic nanoparticles and catechol containing microgels

Phenol and its derivatives are the most used polymerization inhibitors for vinyl-based monomers. Here, we reported a novel catalytic system composed of mussel inspired adhesive moiety, catechol, in combination with iron oxide nanoparticles (IONPs) to generate hydroxyl radical (•OH) at pH 7.4. Catechol-containing microgel (DHM) was prepared by copolymerizing dopamine methacrylamide (DMA) and N-hydroxyethyl acrylamide (HEAA), which generated superoxide (•O₂^-) and hydrogen peroxide (H₂O₂) as a result of catechol oxidation. In the presence of IONPs, the generated reactive oxygen species were further converted to •OH, which initiated free radical polymerization of various water-soluble acrylate-based monomers including neutral (acrylamide, methyl acrylamide, etc.), anionic (2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt), cationic ([2-(methacryloyloxy)ethyl]trimethylammonium chloride), and zwitterionic (2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) monomers. Compared with the typical free radical initiating systems, the reported system does not require the addition of extra initiators for polymerization. During the process of polymerization, a bilayer hydrogel was formed in situ and exhibited the ability to bend during the process of swelling. The incorporation of IONPs significantly enhanced magnetic property of the hydrogel and the combination of DHM and IONPs also improved the mechanical properties of these hydrogels.

Early Identification of Root Damages Caused by Western Corn Rootworms Using a Minimally Invasive Root Phenotyping Robot-MISIRoot

Western corn rootworm (WCR) is one of the most devastating corn rootworm species in North America because of its ability to cause severe production loss and grain quality damage. To control the loss, it is important to identify the infection of WCR at an early stage. Because the root system is the earliest feeding source of the WCR at the larvae stage, assessing the direct damage in the root system is crucial to achieving early detection. Most of the current methods still necessitate uprooting the entire plant, which could cause permanent destruction and a loss of the original root's structural information. To measure the root damages caused by WCR non-destructively, this study utilized MISIRoot, a minimally invasive and in situ automatic plant root phenotyping robot to collect not only high-resolution images but also 3D positions of the roots without uprooting. To identify roots in the images and to study how the damages were distributed in different types of roots, a deep convolution neural network model was trained to differentiate the relatively thick and thin roots. In addition, a color camera was used to capture the above-ground morphological features, such as the leaf color, plant height, and side-view leaf area. To check if the plant shoot had any visible symptoms in the inoculated group compared to the control group, several vegetation indices were calculated based on the RGB color. Additionally, the shoot morphological features were fed into a PLS-DA model to differentiate the two groups. Results showed that none of the above-ground features or models output a statistically significant difference between the two groups at the 95% confidence level. On the contrary, many of the root structural features measured using MISIRoot could successfully differentiate the two groups with the smallest t-test p-value of 1.5791 × 10^-6. The promising outcomes were solid proof of the effectiveness of MISIRoot as a potential solution for identifying WCR infestations before the plant shoot showed significant symptoms.

Sorption and Desorption of Vapor of n-Pentane by Porphyrin Aluminum Metal-Organic Framework: Mechanism of Bonding, Kinetics and Stoichiometry by Complementary In-Situ Time-Dependent and Ex-Situ Methods

Metal-organic frameworks (MOFs) are highly nanostructured coordination polymers that contain metal cations and organic linkers and feature very large pore volumes and surface areas. The sorption and desorption of n-pentane vapor by porphyrin aluminum metal-organic framework Al-MOF-TCPPH₂ where TCPPH₂ is tetrakis(4-carboxyphenyl)porphyrin linker were studied by a novel method of in-situ time-dependent attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy in a controlled atmosphere and complementary in-situ and ex-situ methods. Sorption facilely occurs in the flow of dried air, and in the obtained adsorption complex the adsorbate molecules interact with phenyl and carboxylate groups of the linker and the O-H group. Sorption kinetics follows the pseudo-first-order rate law, as confirmed by in-situ time-dependent gravimetry. Further, an ex-situ (static) sorption of n-pentane vapor results in an adsorption complex with as much as 29.1 wt.% n-pentane with the stoichiometric formula [Al-MOF-TCPPH₂]₂(n-C₅H₁₂)₇ and a distinct XRD pattern. Finally, in the flow of dried air, the adsorption complex gradually desorbed n-pentane, following the pseudo-first-order rate law. The reversibility of sorption and desorption makes porphyrin aluminum MOF promising for the separation of light hydrocarbons and chemo-sensing. In-situ time-dependent ATR-FTIR spectroscopy in a controlled atmosphere, in combination with in-situ time-dependent gravimetry, is a new approach for the determination of binding sites of sorbents with adsorbate molecules, the stoichiometry of complexes, and chemical kinetics of "solid-gas" interactions.

A Feasibility Study of In-Situ Damage Visualization in Basalt-Fiber Reinforced Polymers with Open-Source Digital Volume Correlation

This work analyses damage formation within the bulk of basalt fiber-reinforced polymers (BFRP) by means of open-source Digital Volume Correlation (DVC). Volumetric image data were obtained from conventional in-situ X-Ray computed micro-tomography (µCT) of samples loaded in tension. The open-source image registration toolkit Elastix was employed to obtain full 3D displacement fields from the image data. We assessed the accuracy of the DVC results using the method of manufactured solution and showed that the approach followed here can detect deformation with a magnitude in the order of a fiber diameter which in the present case is 17 µm. The beneficial influence of regularization on DVC results is presented on the manufactured solution as well as on real in-situ tensile testing CT data of a BFRP sample. Results of the correlation showed that conventional µCT equipment in combination with DVC can be used to detect defects which could previously only be visualized using synchrotron facilities or destructive methods.

Experimental Investigation on the Use of a PEI Foam as Core Material for the In-Situ Production of Thermoplastic Sandwich Structures Using Laser-Based Thermoplastic Automated Fiber Placement

Laser-based thermoplastic automated fiber placement (TAFP) is nowadays mainly used to produce pure carbon fiber-reinforced plastic (CFRP) structures. This paper investigates the feasibility of a novel application: The deposition of thermoplastic prepreg tapes onto a thermoplastic foam for the production of thermoplastic sandwich structures. Therefore, simple deposition experiments of thermoplastic PEEK/CF prepreg tapes on a PEI closed-cell foam were carried out. 3D surface profile measurements and peel tests according to DIN EN 28510-1 standard were used to investigate the joining area and bonding quality. The results show that a cohesive bond is formed between the deposited tapes and the foam core, however the foam structure in the area of the deposited tapes deforms in dependence of the process parameters, and increasingly with higher deposition temperatures. Due to the deformations that occur during tape deposition, the thermomechanical foam behavior under the TAFP process conditions was investigated in more detail in a subsequent study for an extensive parameter space using a simple experimental setup. Results show that for suitable process parameters, namely a short contact time and a high temperature, the foam deformation can be minimized with the simultaneous formation of a thin melting layer required for cohesive bonding. The inner foam core structure remains unaffected.

In-situ Spontaneous Fabrication of Tough and Stretchable Polyurethane-Polyethyleneimine Hydrogels Selectively Triggered by CO2

We develop CO₂ -triggered in-situ hydrogels from waterborne poly(ε-caprolactone)-based polyurethane (PU) dispersion and aqueous polyethyleneimine (PEI) solution without any other chemicals and apparatus (e.g., UV light). In our approach, non-toxic CO₂ in air is used as a selective trigger for the hydrogel formation. CO₂ adsorption onto PEI results in the formation of ammonium cations in PEI and the subsequent multiple ionic crosslinking between PU and PEI chains. Besides the amount of CO₂ in air, the rate of hydrogel formation can be controlled by NaHCO₃ in the PU-PEI mixture, which serves as a CO₂ supplier. The PU hydrogels exhibit tough and stretchable properties with high tensile strength (2.05 MPa) and elongation at break (438.24%), as well as biocompatibility and biodegradability. In addition, the PU hydrogels exhibit high adhesion strength on skin and injectability due to the in-situ formation. We believe that these PU hydrogels have the ideal features for various future applications, such as tissue adhesion barriers, wound dressing, artificial skin, and injectable fillers. This article is protected by copyright. All rights reserved.

Growth and Persistence of an Aerobic Microbial Community in Wyoming Bentonite MX-80 Despite Anoxic in situ Conditions

Microbial activity has the potential to enhance the corrosion of high-level radioactive waste disposal canisters, which, in the proposed Swiss deep geological repository, will be embedded in bentonite and placed in the Opalinus Clay (OPA) rock formation. A total of 12 stainless steel cylindrical vessels (referred to as modules) containing bentonite were deployed in an anoxic borehole in OPA for up to 5.5 years. Carbon steel coupons were embedded in the bentonite. Individual modules were retrieved after 1, 1.5, 2.5, and 5.5 years. Enumeration of aerobic and anaerobic heterotrophs and sulfate-reducing bacteria (SRB) revealed microbial growth for 1.5 years followed by a decline or stagnation in microbial viability. It was surprising to observe the growth of aerobic heterotrophs followed by their persistent viability in bentonite, despite the nominally anoxic conditions. In contrast, SRB numbers remained at very low levels. DNA-based amplicon sequencing confirmed the persistence of aerobes and the relatively low contribution of anaerobes to the bentonite microbiome. Bentonite dry density, in situ exposure time, and bioavailable trapped oxygen are observed to shape the bentonite microbial community in the clay.

Fabrication of highly sensitive and uniform Ag/PS/PDMS SERS substrate and its application forin-situdetection

In this study, we developed a flexible and transparent silver/polystyrene/polydimethylsiloxane (Ag/PS/PDMS) substrate with both high density of hot spots and satisfactory uniformity using a cost-effective approach. Via template-guided self-assembly, PS beads were arranged regularly in nanobowls of a square array on PDMS, whose surface structure was transferred from a commercial complementary metal oxide semiconductor chip. Roughness was introduced onto the PS bead surface by nitrogen plasma treatment, followed by sputtering of Ag which generated many hot spots. Differential roughness on the PS bead surface greatly influenced the morphology of the Ag/PS/PDMS substrate. A meat-ball like surface structure was formed with a plasma etching time of 5 min, whose growth mechanism was proposed based on the scanning electron microscope analysis. The high sensitivity and desirable uniformity of the meat-ball like Ag/PS/PDMS substrate were demonstrated by using crystal violet as a Raman reporter, exhibiting an enhancement factor of 2.7 × 10⁷and a relative standard deviation of 5.04%. Thiram of a lower concentration than the maximum residue limit on the cucumber surface could easily be detectedin situby the proposed substrate, demonstrating its great potential forin-situfood safety analysis.

Inhibition of vacuum sublimation artefacts for (Scanning) Transmission Electron Microscopy ((S)TEM) of sulphur samples via encapsulation

Lithium-sulfur battery is one of promising candidates for next-generation energy storage device due to the sulfur cathode material with low cost and nontoxicity, and super high theoretical energy density (nearly 2600Wh kg -1) and specific energy (2567Wh kg -1). Sulphur, however, poses a few interesting challenges before it can gain widespread utilisation. The biggest issue is known as the polysulphide shuttling effect which contributes to rapid capacity loss after cycling. Accurate characterisation of sulphur cathodic materials becomes critical to our understanding polysulphide shuttling effect in the quest of finding mitigating solutions. Electron microscopy is playing a crucial role in battery research in determining structure-property-function relations. However, sulphur undergoes sublimation at a point above the typical pressures found in the column of a transmission electron microscope (TEM) at room temperature. This makes the imaging and characterisation of any sort of nanostructured sulphur samples challenging, as the material will be modified or even disappear rapidly as soon as it is inserted into the TEM vacuum. As a result, materials characterised by such methods are prone to deviation from normal conditions to a great extent. To prevent this, a novel method of encapsulating sulphur particles between silicon nitride (SiN x) membranes is demonstrated in this work.

Implementation of level-2 biosafety for a macromolecular crystallography beamline at SSRF

Macromolecular crystallography is commonly used to determine the structure of biological macromolecules. Currently the beamlines at synchrotron radiation facilities play an important role in macromolecular crystallography, and have produced an enormous number of molecular structures to help solve scientific questions and support applications. Structure information makes significant contributions to the virus-related research as well. However, it is mandatory to be protected the operators under a compatible biosafety infrastructure when a pathological agent is set up in a beamline. Here a level-2 biosafety protection for a macromolecular crystallography beamline at Shanghai Synchrotron Radiation Facility (SSRF) is introduced. To fulfill the biosafety in a radioactive environment, a dedicated design is implemented. Since the beamline will be opened to the external users from nationwide research units, the management process and experimental method are also drawn up.

A proof-of-concept study of an in-situ partial-ring time-of-flight PET scanner for proton beam verification

Development of a PET system capable of in-situ imaging requires a design that can accommodate the proton treatment beam nozzle. Among the several PET instrumentation approaches developed thus far, the dual-panel PET scanner is often used as it is simpler to develop and integrate within the proton therapy gantry. Partial-angle coverage of these systems can however lead to limited-angle artefacts in the reconstructed PET image. We have previously demonstrated via simulations that time-of-flight (TOF) reconstruction reduces the artifacts accompanying limited-angle data, and permits proton range measurement with 1-2 mm accuracy and precision. In this work we show measured results from a small proof-of-concept dual-panel PET system that uses TOF information to reconstruct PET data acquired after proton irradiation. The PET scanner comprises of two detector modules, each comprised of an array of 4×4×30 mm³ lanthanum bromide scintillator. Measurements are performed with an oxygen-rich gel-water, an adipose tissue equivalent material, and in vitro tissue phantoms. For each phantom measurement, 2 Gy dose was deposited using 54 - 100 MeV proton beams. For each phantom, a Monte Carlo simulation generating the expected distribution of PET isotope from the corresponding proton irradiation was also performed. Proton range was calculated by drawing multiple depth-profiles over a central region encompassing the proton dose deposition. For each profile, proton range was calculated using two techniques (a) 50% pick-off from the distal edge of the profile, and (b) comparing the measured and Monte Carlo profile to minimize the absolute sum of differences over the entire profile. A 10 min PET acquisition acquired with minimal delay post proton-irradiation is compared with a 10 min PET scan acquired after a 20 min delay. Measurements show that PET acquisition with minimal delay is necessary to collect ¹⁵O signal, and maximize ¹¹C signal collection with a short PET acquisition. In comparison with the 50% pick-off technique, the shift technique is more robust and offers better precision in measuring the proton range for the different phantoms. Range measurements from PET images acquired with minimal delay, and the shift technique demonstrate the ability to achieve <1.5 mm accuracy and precision in estimating proton range.

Machine Learning Assisted Classification of Aluminum Nitride Thin Film Stress via In-Situ Optical Emission Spectroscopy Data

In this study, we submit a complex set of in-situ data collected by optical emission spectroscopy (OES) during the process of aluminum nitride (AlN) thin film. Changing the sputtering power and nitrogen(N₂) flow rate, AlN film was deposited on Si substrate using a superior sputtering with a pulsed direct current (DC) method. The correlation between OES data and deposited film residual stress (tensile vs. compressive) associated with crystalline status by X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) measurements were investigated and established throughout the machine learning exercise. An important answer to know is whether the stress of the processing film is compressive or tensile. To answer this question, we can access as many optical spectra data as we need, record the data to generate a library, and exploit principal component analysis (PCA) to reduce complexity from complex data. After preprocessing through PCA, we demonstrated that we could apply standard artificial neural networks (ANNs), and we could obtain a machine learning classification method to distinguish the stress types of the AlN thin films obtained by analyzing XRD results and correlating with TEM microstructures. Combining PCA with ANNs, an accurate method for in-situ stress prediction and classification was created to solve the semiconductor process problems related to film property on deposited films more efficiently. Therefore, methods for machine learning-assisted classification can be further extended and applied to other semiconductors or related research of interest in the future.

Instant in-situ Tissue Repair by Biodegradable PLA/Gelatin Nanofibrous Membrane Using a 3D Printed Handheld Electrospinning Device

Background: This study aims to design a 3D printed handheld electrospinning device and evaluate its effect on the rapid repair of mouse skin wounds.

Methods: The device was developed by Solidworks and printed by Object 350 photosensitive resin printer. The polylactic acid (PLA)/gelatin blend was used as the raw material to fabricate in-situ degradable nanofiber scaffolds. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and water vapor permeability test were used to evaluate the material properties of the scaffolds; cytotoxicity test was performed to evaluate material/residual solvent toxicity, and in situ tissue repair experiments in Balb/c mouse were performed.

Results: The 3D printed handheld electrospinning device successfully fabricates PLA/gelatin nanofibrous membrane with uniformly layered nanofibers and good biocompatibility. Animal experiments showed that the mice in the experimental group had complete skin repair.

Conclusions: The 3D printed handheld device can achieve in situ repair of full-thickness defects in mouse skin.

Enhancing CO2 Catalytic Adsorption on an Fe Nanoparticle-Decorated LaSrFeO4 + δ Cathode for CO2 Electrolysis

The development of cathode materials with high catalytic activity and low cost is a challenge for CO₂ electrolysis based on solid oxide electrolysis cells. Herein, we report a low-cost and highly active metallic Fe nanoparticle-decorated Ruddlesden-Popper (La, Sr)FeO_4+δ cathode catalyst (Fe-RPLSF), which shows a high oxygen vacancy concentration and robust CO₂ reduction rate. At 850 °C, the current density of the electrolysis cell with the Fe-RPLSF cathode reaches -1920 mA cm^-2 at a voltage of 1.5 V, and the Faraday efficiency is as high as 100%. The polarization resistance at low frequency (0.1-10 Hz), which is the rate-limit step for CO₂ electrolysis, significantly decreases with the exsolved Fe nanoparticles because of improved CO₂ dissociative adsorption. Moreover, our electrolysis cell demonstrates acceptable short-term stability for direct CO₂ electrolysis.

Twelve Tips for running in-situ simulation during a Coronavirus pandemic

This article was migrated. The article was marked as recommended. The arrival of the coronavirus pandemic has caused massive disruption to medical education, with universities having to close and adopt new ways of teaching, ensuring social distancing as standard. Final year medical students from the University of Aberdeen graduated early and stepped up to start working as 'Foundation interim Year 1 doctors' (FiY1). With their final months of medical school and end of year examinations cancelled, we felt that an in-situ ward simulation would help them make that transition by giving them an opportunity to act up in a safe environment. Here we share our tips for designing and implementing an in-situ simulation aimed at junior doctors in the early stages of their training. We conclude by reflecting on what we have learnt and how we plan to take this method of simulation forward into future practice, once the pandemic is over.

4D In-Situ Microscopy of Aerosol Filtration in a Wall Flow Filter

The transient nature of the internal pore structure of particulate wall flow filters, caused by the continuous deposition of particulate matter, makes studying their flow and filtration characteristics challenging. In this article we present a new methodology and first experimental demonstration of time resolved in-situ synchrotron micro X-ray computed tomography (micro-CT) to study aerosol filtration. We directly imaged in 4D (3D plus time) pore scale deposits of TiO2 nanoparticles (nominal mean primary diameter of 25 nm) with a pixel resolution of 1.6 μm. We obtained 3D tomograms at a rate of ∼1 per minute. The combined spatial and temporal resolution allows us to observe pore blocking and filling phenomena as they occur in the filter’s pore space. We quantified the reduction in filter porosity over time, from an initial porosity of 0.60 to a final porosity of 0.56 after 20 min. Furthermore, the penetration depth of particulate deposits and filtration rate was quantified. This novel image-based method offers valuable and statistically relevant insights into how the pore structure and function evolves during particulate filtration. Our data set will allow validation of simulations of automotive wall flow filters. Evolutions of this experimental design have potential for the study of a wide range of dry aerosol filters and could be directly applied to catalysed automotive wall flow filters.

Contribution of Ex-Situ and In-Situ X-ray Grazing Incidence Scattering Techniques to the Understanding of Quantum Dot Self-Assembly: A Review

Quantum dots are under intense research, given their amazing properties which favor their use in electronics, optoelectronics, energy, medicine and other important applications. For many of these technological applications, quantum dots are used in their ordered self-assembled form, called superlattice. Understanding the mechanism of formation of the superlattices is crucial to designing quantum dots devices with desired properties. Here we review some of the most important findings about the formation of such superlattices that have been derived using grazing incidence scattering techniques (grazing incidence small and wide angle X-ray scattering (GISAXS/GIWAXS)). Acquisition of these structural information is essential to developing some of the most important underlying theories in the field.

In situ solid-state NMR characterization of pharmaceutical materials: An example of drug-polymer thermal mixing

Pharmaceutical amorphous solid dispersions, a multicomponent system prepared by dispersing drug substances into polymeric matrix via thermal and mechanical processes, represent a major platform to deliver the poorly water-soluble drug. Microscopic properties of drug-polymer contacts play mechanistic roles in manipulating long-term physical stability as well as dissolution profiles. Although solid-state nuclear magnetic resonance has been utilized as an indispensable tool to probe structural details, previous studies are limited to ex situ characterizations. Our work provides likely the first documented example to investigate comelting of ketoconazole and polyacrylic acid, as a model system, in an in situ manner. Their physical mixture is melted and mixed in the solid-state nuclear magnetic resonance rotor under magic angle spinning at up to approximately 400 K. Critical structural events of molecular miscibility and interaction have been successfully identified. These results design and evaluate the instrumental and experimental protocols for real-time characterizations of the comelting of pharmaceutical materials.

Microstructure Features and High Temperature Oxidation Resistance of In-Situ TiN-Ti Composite Coatings by Plasma Transferred Arc Welding

In order to improve the high temperature oxidation resistance of Ti6Al4V alloy, the in-situ TiN-Ti composite coatings were prepared with Ti-Cr-Ni-Nb powders by plasma transferred arc welding. Nitrogen gas was used as the transport gas and provided N source for the formation reaction of TiN. Microstructure features and high temperature oxidation behaviors of the composite coatings were studied. The phases in the composite coatings were TiN, Ti, CrN, and NiTi. It was clearly observed that in-situ TiN particles were evenly distributed in the Ti matrix. A little Nb atom dissolved in TiN particles, and others dissolved in the Ti matrix. By comparing the curve of Ti6Al4V alloy to that of the composite coatings, the oxidation mass gain of the composite coatings was comparatively less. The oxidation film of the composite coatings was smooth and compact, and no crack was visibly observed. Based on the results of the high temperature tests, the composite coatings exhibited superior high temperature oxidation resistance than Ti6Al4V alloy both at 650 °C and at 850 °C.

Microstructure and Wear Behavior of In-Situ NbC Reinforced Composite Coatings

In the present study, plasma spray welding was used to prepare an in-situ niobium carbide (NbC) reinforced Ni-based composite coating on the low carbon steel, and the phase composition and the microstructure of the composite coatings were studied. The wear resistance and the wear mechanism of the composite coatings were also researched by the wear tests. The results showed that the main phases of the composite coating were NbC, γ-Ni, Cr23C6, Ni3Si, CrB, Cr5B3, Cr7C3 and FeNi3. A number of fine in-situ NbC particles and numerous chromium carbide particles were distributed in the γ-Ni matrix. The increase in the mass fraction of Nb and NiCr-Cr3C2 could lead to the increase in NbC particles in the composite coatings. Due to the high hardness of NbC and chromium carbides, the micro-hardness and the wear resistance of the composite coatings were advanced. The composite coating with the powder mixtures of 20% (Nb + NiCr-Cr3C2) and 80% NiCrBSi had the highest micro-hardness and the best wear resistance in this study. The average micro-hardness reached the maximum value 1025HV0.5. The volume loss was 39.2 mm3, which was merely 37% of that of the NiCrBSi coating and 6% of that of the substrate under the identical conditions.

Thermal and Fire Behavior of a Bio-Based Epoxy/Silica Hybrid Cured with Methyl Nadic Anhydride

Thermosetting polymers have been widely used in many industrial applications as adhesives, coatings and laminated materials, among others. Recently, bisphenol A (BPA) has been banned as raw material for polymeric products, due to its harmful impact on human health. On the other hand, the use of aromatic amines as curing agents confers excellent thermal, mechanical and flame retardant properties to the final product, although they are toxic and subject to governmental restrictions. In this context, sugar-derived diepoxy monomers and anhydrides represent a sustainable greener alternative to BPA and aromatic amines. Herein, we report an "in-situ" sol-gel synthesis, using as precursors tetraethylorthosilicate (TEOS) and aminopropyl triethoxysilane (APTS) to obtain bio-based epoxy/silica composites; in a first step, the APTS was left to react with 2,5-bis[(oxyran-2-ylmethoxy)methyl]furan (BOMF) or diglycidyl ether of bisphenol A (DGEBA)monomers, and silica particles were generated in the epoxy in a second step; both systems were cured with methyl nadic anhydride (MNA). Morphological investigation of the composites through transmission electron microscopy (TEM) demonstrated that the hybrid strategy allows a very fine distribution of silica nanoparticles (at nanometric level) to be achieved within a hybrid network structure for both the diepoxy monomers. Concerning the fire behavior, as assessed in vertical flame spread tests, the use of anhydride curing agent prevented melt dripping phenomena and provided high char-forming character to the bio-based epoxy systems and their phenyl analog. In addition, forced combustion tests showed that the use of anhydride hardener instead of aliphatic polyamine results in a remarkable decrease of heat release rate. An overall decrease of the smoke parameters, which is highly desirable in a context of greater fire safety was observed in the case of BOMF/MNA system. The experimental results suggest that the effect of silica nanoparticles on fire behavior appears to be related to their dispersion degree.

In-Situ Fabrication of Bone-Like CoSe2 Nano-Thorn Loaded on Porous Carbon Cloth as a Flexible Electrode for Na-Ion Storage

Sodium-ion batteries (SIBs) based on flexible electrode materials are being investigated recently for improving sluggish kinetics and developing energy density. Transition metal selenides present excellent conductivity and high capacity; nevertheless, their low conductivity and serious volume expansion raise challenging issues of inferior lifespan and capacity fading. Herein, an in-situ construction method through carbonization and selenide synergistic effect is skillfully designed to synthesize a flexible electrode of bone-like CoSe₂ nano-thorn coated on porous carbon cloth. The designed flexible CoSe₂ electrode with stable structural feature displays enhanced Na-ion storage capabilities with good rate performance and outstanding cycling stability. As expected, the designed SIBs with flexible BL-CoSe₂ /PCC electrode display excellent reversible capacity with 360.7 mAh g^-1 after 180 cycles at a current density of 0.1 A g^-1 .

Melamine Foams Decorated with In-Situ Synthesized Gold and Palladium Nanoparticles

A versatile and straightforward route to produce polymer foams with functional surface through their decoration with gold and palladium nanoparticles is proposed. Melamine foams, used as polymeric porous substrates, are first covered with a uniform coating of polydimethylsiloxane, thin enough to assure the preservation of their original porous structure. The polydimethylsiloxane layer allows the facile in-situ formation of metallic Au and Pd nanoparticles with sizes of tens of nanometers directly on the surface of the struts of the foam by the direct immersion of the foams into gold or palladium precursor solutions. The effect of the gold and palladium precursor concentration, as well as the reaction time with the foams, to the amount and sizes of the nanoparticles synthesized on the foams, was studied and the ideal conditions for an optimized functionalization were defined. Gold and palladium contents of about 1 wt.% were achieved, while the nanoparticles were proven to be stably adhered to the foam, avoiding potential risks related to their accidental release.

3D Ultrasensitive Polymers-Plasmonic Hybrid Flexible Platform for In-Situ Detection

This paper introduces a three-dimensional (3D) pyramid to the polymers-plasmonic hybrid structure of polymethyl methacrylate (PMMA) composite silver nanoparticle (AgNPs) as a higher quality flexible surface-enhanced Raman scattering (SERS) substrate. Benefiting from the effective oscillation of light inside the pyramid valley could provide wide distributions of 3D “hot spots” in a large space. The inclined surface design of the pyramid structure could facilitate the aggregation of probe molecules, which achieves highly sensitive detection of rhodamine 6G (R6G) and crystal violet (CV). In addition, the AgNPs and PMMA composite structures provide uniform space distribution for analyte detection in a designated hot spot zone. The incident light can penetrate the external PMMA film to trigger the localized plasmon resonance of the encapsulated AgNPs, achieving enormous enhancement factor (~6.24×108). After undergoes mechanical deformation, the flexible SERS substrate still maintains high mechanical stability, which was proved by experiment and theory. For practical applications, the prepared flexible SERS substrate is adapted to the in-situ Raman detection of adenosine aqueous solution and the methylene-blue (MB) molecule detection of the skin of a fish, providing a direct and nondestructive active-platform for the detecting on the surfaces with any arbitrary morphology and aqueous solution.

Improvement in Cobalt Phosphate Electrocatalyst Activity toward Oxygen Evolution from Water by Glycine Molecule Addition and Functional Details

Electrochemical water splitting using renewable energy shows promise for the development of sustainable hydrogen production methods. The process requires a highly active electrocatalyst for oxygen evolution to improve the overall water splitting efficiency. The present study showed that oxygen evolution improved dramatically upon the addition of glycine to cobalt phosphate, when the glycine was added to the electrolyte solution during electrodeposition. The functionality of the organic molecules was investigated using in situ UV-vis absorption, in situ X-ray absorption fine structure, and in situ infrared (IR) absorption spectroscopy in the attenuated total reflection mode. The results demonstrated that the glycine molecules assembled cobalt oxide clusters composed of CoO₆ (CoOOH) octahedrons a few nanometers in diameter upon the electrodeposition of cobalt catalysts. This suggests that the cobalt-glycine catalyst can decompose water to oxygen gas efficiently, because the number of cobalt oxide clusters increased as active reaction sites upon the addition of glycine molecules.

Micro Electrochemical Machining of Array Micro-Grooves Using In-Situ Disk Electrode Fabricated by Micro-WEDM

This paper develops an array micro-grooves manufacturing method using micro electrochemical machining (ECM) with disk electrode, which is prepared by in-situ micro wire electrical discharge machining (WEDM). This technology focuses on the difficulty of array structure manufacture in micro-electro-mechanical systems (MEMS). A micro-ECM system is built based on the micro-WEDM machine to achieve high precision processing of the array micro-grooves. Since micro-WEDM has good performance in high precision machining of the rotating structure, single and multi-edge disk electrodes can be fabricated in-situ using graphite. The as-prepared disk tool electrode is directly used for micro-electrochemical milling of the array micro-grooves without disassembling away from the device, which avoids the positioning error caused by the re-clamping of the disk electrode. With the advantages of high surface quality and no electrode loss, micro-ECM improves the manufacture performance of the micro-parts. Through wire path optimization, the shape accuracy of the disk edge is improved. After the research of the micro-ECM parameters, the process is improved, and finally, the high precision array micro-grooves are obtained. This method combines the advantages of micro-WEDM and disk electrode micro-ECM milling, and it is convenient for large-scale manufacture of array micro-structures on micro-parts and MEMS.

Investigating Helium Bubble Nucleation and Growth through Simultaneous In-Situ Cryogenic, Ion Implantation, and Environmental Transmission Electron Microscopy

Palladium can readily dissociate molecular hydrogen at its surface, and rapidly accept it onto the octahedral sites of its face-centered cubic crystal structure. This can include radioactive tritium. As tritium β-decays with a half-life of 12.3 years, He-3 is generated in the metal lattice, causing significant degradation of the material. Helium bubble evolution at high concentrations can result in blister formation or exfoliation and must therefore be well understood to predict the longevity of materials that absorb tritium. A hydrogen over-pressure must be applied to palladium hydride to prevent hydrogen from desorbing from the metal, making it difficult to study tritium in palladium by methods that involve vacuum, such as electron microscopy. Recent improvements in in-situ ion implantation Transmission Electron Microscopy (TEM) allow for the direct observation of He bubble nucleation and growth in materials. In this work, we present results from preliminary experiments using the new ion implantation Environmental TEM (ETEM) at the University of Huddersfield to observe He bubble nucleation and growth, in-situ, in palladium at cryogenic temperatures in a hydrogen environment. After the initial nucleation phase, bubble diameter remained constant throughout the implantation, but bubble density increased with implantation time. β-phase palladium hydride was not observed to form during the experiments, likely indicating that the cryogenic implantation temperature played a dominating role in the bubble nucleation and growth behavior.

[Combined application of SNAP-tag and fluorescence technique in in-situ protein analysis]

The visualization of the microcosmic behavior of proteins in vivo is the key to real-time monitoring of proteins. A series of wash-free SNAP-tag probes were designed and synthesized based on the combination of SNAP-tag and small organic molecule fluorescent dyes. SNAP-tag, which specifically recognized O6-benzylguanine, could be labeled with a fluorophore (e. g., 1,8-naphthalimide) through the formation of covalent bonds. Furthermore, the change from a hydrophilic environment to the hydrophobic cavum of SNAP-tag realized a 2-13-fold enhancement in fluorescence. Through the fusion of SNAP-tag and the target protein, the probes could recognize the mitochondrial proteins (e. g., cytochrome oxidase, Cox8A) and nuclear proteins (e. g., H2B) in living cells. Besides, the fluorescent probes allowed the in-situ real-time monitoring of proteins without washing.

Ultrathin-Layer Structure of BiOI Microspheres Decorated on N-Doped Biochar With Efficient Photocatalytic Activity

Bismuth oxyiodide (BiOI) is among the most potential photocatalysts due to its photocatalytic activity under visible light irradiation. However, the photoinduced carrier separation efficiency has limited the BiOI photocatalytic activity. Herein, we utilized the direct carbonation of sapless cattail grass to obtain N-doped hierarchical structure cattail-based carbon (NCC). The NCC not only served as an appropriate host but also as a self-sacrificing template for BiOI microspheres for the preparation of BiOI/NCC composite material. The acidic solutions (HCl or AcOH) were used as a solvent which helped to obtain a well-defined micro/nano hierarchical BiOI microspheres composed of ultrathin nanosheets. Thus, BiOI/NCC composites were successfully designed through the in-situ self-template rapid dissolution-recrystallization mechanism. Additionally, numerous well-contacted interfaces were formed between NCC and BiOI, which served as an electron-acceptor bridge function for ultrafast electron transfer process in order to hinder the electron-hole pairs recombination. On account of the multiple synergistic effects of micro/nano hierarchical microsphere structure, ultrathin nanosheets, and well-contacted interface, the as-prepared BiOI/NCC composites exhibit the superior degradation of rhodamine B (RhB) than pure BiOI under visible light irradiation.

An interprofessional training program for intrahospital transport of critically ill patients: model build-up and assessment

Intrahospital transport of critically ill patients for diagnostic or therapeutic procedures can be compromised by patient instability, equipment problems or inexperienced teamworking. This quasi-experimental study aimed to assess the effectiveness of an in-situ interprofessional simulation-based training (IIST) model for junior member transport teams. Newly registered postgraduate physicians, nurses and respiratory therapists underwent the IIST. The technical skills (TS) of each participant and non-technical skills (NTS) of each interprofessional team were assessed using well-validated checklists. Thirty-six participants enrolled and were randomly assigned to six experimental and six control teams. Most participants achieved a significantly higher level of both TS and NTS. Both the control and experimental teams overvalued their NTS in the pretest, while the posttest self-assessment scores among the experimental groups more closely matched the expert assessments. Despite challenges in scheduling and the setting, the IIST was successfully conducted in a crowded hospital, which enabled trainees to optimize their learning in a real-life environment. In conclusion, the IIST model can facilitate the development of both TS and NTS for transport team members. Transport teams made up of newly registered staff from different disciplines may lack insight into their NTS in critical patient transfer management, but simulation training may cause improvements.

In-situ Raman spectroscopic measurements of the deformation region in indented glasses

This paper describes the design and integration of a custom-built optical instrument for in-situ Raman microscopy suitable for collecting high-quality spectroscopic data during the indentation of glass materials. It will further show that the reported experimental setup enables meaningful in-situ spectroscopic observations during indentation of fused silica at forces in the millinewton range. The aim of the paper is to demonstrate the vital importance of matching the analysis volume of the Raman microscope with the indentation-induced deformation volume to capture the full extent of the related spectral alterations by minimizing spectral contributions from the unperturbed bulk material (in-situ and ex-situ) and indenter probe (in-situ only). In this context, the paper will also touch upon possible pitfalls in ex-situ and in-situ Raman measurements on indented glasses in cases where the analysis and deformation volumes are not well matched and describe the misinterpretations that may result.

Spatio-Temporal Differences in Nitrogen Reduction Rates under Biotic and Abiotic Processes in River Water of the Taihu Basin, China

Understanding spatio-temporal differences in nitrogen (N) transformation, transport and reduction rates in water bodies is critical to achieve effective mitigation of river eutrophication. We performed culture experiments in six rivers in the Taihu Basin using a custom made in-situ experimental apparatus. We investigated spatio-temporal differences in reduce processes and rates of different N forms and assessed the contribution of biological processes to dissolved inorganic N (DIN) reduce. Results showed that biological processes played a major role in N reduction in summer, while non-microbial processes were dominant in winter. We observed significant spatial and temporal differences in the studied mechanisms, with reduction rates of different N compounds being significantly higher in summer and autumn than spring and winter. Reduction rates ranged from 105.4 ± 25.3 to 1458.8 ± 98.4 mg·(m³·d)^-1 for total N, 33.1 ± 12.3 to 440.9 ± 33.1 mg·(m³·d)^-1 for ammonium, 56.3 ± 22.7 to 332.1 ± 61.9 mg·(m³·d)^-1 for nitrate and 0.4 ± 0.3 to 31.8 ± 9.0 mg·(m³·d)^-1 for nitrite across four seasons. Mean DIN reduction rates with and without microbial activity were 96.0 ± 46.4 mg·(m³·d)^-1 and 288.1 ± 67.8 mg·(m³·d)^-1, respectively, with microbial activity rates accounting for 29.7% of the DIN load and 2.2% of the N load. Results of correlation and principal component analysis showed that the main factors influencing N processing were the concentrations of different N forms and multiple environmental factors in spring, N concentrations, DO and pH in summer, N concentrations and water velocity in autumn and N concentrations in winter.

Stem Cell-Mediated Angiogenesis in Tissue Engineering Constructs

Angiogenesis has always been a concern in the field of tissue engineering. Poor vascularization of engineered constructs is a problem for the clinical success of these structures. Among the various methods employed to induce angiogenesis, stem cells provide a promising tool for the future. The present review aims to present the application of stem cells in the induction of angiogenesis. Additionally, it summarizes recent advancements in stem cell-mediated angiogenesis of different tissue engineering constructs.

In-Situ Simulation Enhances Emergency Preparedness in Pediatric Care Practices

Background

It is not uncommon for emergencies to present at primary care offices. As such, it is necessary for those offices to be prepared to handle, at a minimum, the most common types of emergencies.

Objective

To evaluate the effectiveness of in-situ simulation training in improving emergency preparedness within pediatric primary care settings.

Methods

Simulation training was provided at 20 primary care offices in Central Florida. The participants were asked to complete a pre-simulation survey that utilized a five-point Likert-type scale to evaluate office preparedness and the confidence of staff members in managing emergency presentations within their settings. Subsequent to the simulation, participants were asked to complete a post-survey to evaluate the effectiveness of the simulation training.

Results

Primary care office staff members reported an enhanced preparedness in managing emergencies post-simulation training (pre-simulation 2.95 vs. post-simulation 4.02; p-value<0.05). They also reported higher levels of comfort in managing emergency situations after the simulation training (pre-simulation 3.22 vs. post-simulation 4.53; p-value<0.05). Overall, 100% of participants found the simulation to be effective or extremely effective.

Conclusions

Our data suggests that the simulation training has improved office preparedness in managing emergencies in a pediatric primary care setting. The simulation training has also been shown to improve the comfort level of pediatric primary care office staff in handling emergency situations. This study was limited to pediatric primary care settings in the Central Florida region, and it is unclear if the findings of this study are generalizable to all primary care practices. Further studies are required to explore whether such training can result in practice change and improve outcomes for more patients.

Microstructures and Compressive Properties of Al Matrix Composites Reinforced with Bimodal Hybrid In-Situ Nano-/Micro-Sized TiC Particles

Bimodal hybrid in-situ nano-/micro-size TiC/Al composites were prepared with combustion synthesis of Al-Ti-C system and hot press consolidation. Attempt was made to obtain in-situ bimodal-size TiC particle reinforced dense Al matrix composites by using different carbon sources in the reaction process of hot pressing forming. Microstructure showed that the obtained composites exhibited reasonable bimodal-sized TiC distribution in the matrix and low porosity. With the increasing of the carbon nano tube (CNT) content from 0 to 100 wt. %, the average size of the TiC particles decreases and the compressive strength of the composite increase; while the fracture strain increases first and then decreases. The compressive properties of the bimodal-sized TiC/Al composites, especially the bimodal-sized composite synthesized by Al-Ti-C with 50 wt. % CNTs as carbon source, were improved compared with the composites reinforced with single sized TiC. The strengthening mechanism of the in-situ bimodal-sized particle reinforced aluminum matrix composites was revealed.

Mechanisms and FEM Simulation of Chip Formation in Orthogonal Cutting In-Situ TiB₂/7050Al MMC

The in-situ TiB₂/7050Al composite is a new kind of Al-based metal matrix composite (MMC) with super properties, such as low density, improved strength, and wear resistance. This paper, for a deep insight into its cutting performance, involves a study of the chip formation process and finite element simulation during orthogonal cutting in-situ TiB₂/7050Al MMC. With chips, material properties, cutting forces, and tool geometry parameters, the Johnson–Cook (J–C) constitutive equation of in-situ TiB₂/7050Al composite was established. Then, the cutting simulation model was established by applying the Abaqus–Explicit method, and the serrated chip, shear plane, strain rate, and temperature were analyzed. The experimental and simulation results showed that the obtained material’s constitutive equation was of high reliability, and the saw-tooth chips occurred commonly under either low or high cutting speed and small or large feed rate. From result analysis, it was found that the mechanisms of chip formation included plastic deformation, adiabatic shear, shearing slip, and crack extension. In addition, it was found that the existence of small, hard particles reduced the ductility of the MMC and resulted in segmental chips.

Enhancement of Ocular In Situ Gelling Properties of Low Acyl Gellan Gum by Use of Ion Exchange

PURPOSE

The purpose of this study was to determine if the addition of calcium gluconate to gellan solution results in a stronger gel structure on initial exposure to tear fluid due to the displacement of calcium from the gluconate ion by tear monovalent cations (Na⁺, K⁺).

METHODS

Test solutions of gellan and gellan-calcium gluconate were mixed thoroughly with simulated tear fluid (STF) at a 5:1 ratio. The resulting gel was measured for viscosity at 32°C-36°C.

RESULTS

The addition of optimized amounts of calcium gluconate to gellan formulations resulted in gellan-calcium gluconate-STF gels of higher strength (statistically significant) than when gellan alone was mixed with STF. Gellan experimental preparations demonstrated thixotropic behavior both before and after addition of STF.

CONCLUSIONS

It appears possible to enhance the initial in situ gel-forming properties of gellan by adding a divalent cation bound to an ion exchange molecule or resin. Optimal amounts of polyvinylpyrrolidone (PVP) appear to be effective in slowing timolol release when added to gellan and calcium gluconate solutions.

In Situ, High-Resolution Profiles of Labile Metals in Sediments of Lake Taihu

Characterizing labile metal distribution and biogeochemical behavior in sediments is crucial for understanding their contamination characteristics in lakes, for which in situ, high-resolution data is scare. The diffusive gradient in thin films (DGT) technique was used in-situ at five sites across Lake Taihu in the Yangtze River delta in China to characterize the distribution and mobility of eight labile metals (Fe, Mn, Zn, Ni, Cu, Pb, Co and Cd) in sediments at a 3 mm spatial resolution. The results showed a great spatial heterogeneity in the distributions of redox-sensitive labile Fe, Mn and Co in sediments, while other metals had much less marked structure, except for downward decreases of labile Pb, Ni, Zn and Cu in the surface sediment layers. Similar distributions were found between labile Mn and Co and among labile Ni, Cu and Zn, reflecting a close link between their geochemical behaviors. The relative mobility, defined as the ratio of metals accumulated by DGT to the total contents in a volume of sediments with a thickness of 10 mm close to the surface of DGT probe, was the greatest for Mn and Cd, followed by Zn, Ni, Cu and Co, while Pb and Fe had the lowest mobility; this order generally agreed with that defined by the modified BCR approach. Further analyses showed that the downward increases of pH values in surface sediment layer may decrease the lability of Pb, Ni, Zn and Cu as detected by DGT, while the remobilization of redox-insensitive metals in deep sediment layer may relate to Mn cycling through sulphide coprecipitation, reflected by several corresponding minima between these metals and Mn. These in situ data provided the possibility for a deep insight into the mechanisms involved in the remobilization of metals in freshwater sediments.

Synthesis and Mechanical Characterisation of an Ultra-Fine Grained Ti-Mg Composite

The importance of lightweight materials such as titanium and magnesium in various technical applications, for example aerospace, medical implants and lightweight construction is well appreciated. The present study is an attempt to combine and improve the mechanical properties of these two materials by forming an ultra-fine grained composite. The material, with a composition of 75 vol% (88.4 wt%) Ti and 25 vol% (11.4 wt%) Mg , was synthesized by powder compression and subsequently deformed by high-pressure torsion. Using focused ion beam machining, miniaturised compression samples were prepared and tested in-situ in a scanning electron microscope to gain insights into local deformation behaviour and mechanical properties of the nanocomposite. Results show outstanding yield strength of around 1250 MPa, which is roughly 200 to 500 MPa higher than literature reports of similar materials. The failure mode of the samples is accounted for by cracking along the phase boundaries.

Simple NMR methods for evaluating higher order structures of monoclonal antibody therapeutics with quinary structure

Monoclonal antibody (mAb) drugs constitute the largest class of protein therapeutics currently on the market. Correctly folded protein higher order structure (HOS), including quinary structure, is crucial for mAb drug quality. The quinary structure is defined as the association of quaternary structures (e.g., oligomerized mAb). Here, several commonly available analytical methods, i.e., size-exclusion-chromatography (SEC) FPLC, multi-angle light scattering (MALS), circular dichroism (CD), NMR and multivariate analysis, were combined and modified to yield a complete profile of HOS and comparable metrics. Rituximab and infliximab were chosen for method evaluation because both IgG1 molecules are known to be homologous in sequence, superimposable in Fab crystal structure and identical in Fc structure. However, herein the two are identified to be significantly different in quinary structure in addition to minor secondary structure differences. All data collectively showed rituximab was mostly monomeric while infliximab was in mono-oligomer equilibrium driven by its Fab fragment. The quinary structure differences were qualitatively inferred from the less used but more reproducible dilution-injection-SEC-FPLC curve method. Quantitative principal component analysis (PCA) was performed on NMR spectra of either the intact or the in-situ enzymatic-digested mAb samples. The cleavage reactions happened directly in NMR tubes without further separation, which greatly enhanced NMR spectra quality and resulted in larger inter- and intra-lot variations based on PCA. The new in-situ enzymatic digestion method holds potential in identifying structural differences on larger therapeutic molecules using NMR.

Classification of different patterns of pulmonary adenocarcinomas

The epidemic increase of adenocarcinoma histology accounting for more than 50% of primary lung malignancies and the advent of effective molecular targeted-therapies against specific gene alterations characterizing this tumor type have led to the reconsideration of the pathologic classification of lung cancer. The new 2015 WHO classification provided the basis for a multidisciplinary approach emphasizing the close correlation among clinical, radiologic and molecular characteristics and histopathologic pattern of lung adenocarcinoma. The terms 'bronchioloalveolar carcinoma' and 'mixed adenocarcinoma' have been eliminated, introducing the concepts of 'adenocarcinoma in situ', 'minimally invasive adenocarcinoma' and the use of descriptive predominant patterns in invasive adenocarcinomas (lepidic, acinar, papillary, solid and micropapillary patterns). 'Invasive mucinous adenocarcinoma' is the new definition for mucinous bronchioloalveolar carcinoma, and some variants of invasive adenocarcinoma have been included, namely colloid, enteric and fetal-type adenocarcinomas. A concise update of the immunomorphologic, radiological and molecular characteristics of the different histologic patterns of lung adenocarcinoma is reported here.

In-situ Pb(2+) remediation using nano iron particles

Originally, application of nano zero valent iron (nZVI) particles for the removal of lead (Pb(2+)) in porous media was studied. At first, stabilized nZVI (S-nZVI) was prepared and characterized, then used in batch and continuous systems. Based on the batch experiments, corresponding reaction kinetics well fitted with the pseudo-first-order adsorption model, and reaction rate ranged from 0.01 to 0.04 g/mg/min depend on solution pH and the molar ratio between Fe and Pb. In batch tests, optimal condition with more than 90% removal efficiency at 60 min was observed at a pH range of 4 to 6 and Fe/Pb ratio more than 2.5. Continuous experiments exposed that Pb(2+) remediation was as well influenced by seepage velocity, grain size, and type of porous media. The maximum Pb(2+) removal efficiency in batch and bench-scale systems were 97% and 81%, correspondingly. The results have shown the ability of S-nZVI to use in permeable reactive barriers, as an efficient adsorbent for Pb(2+), because of its excellent stability, high reducing power, and a large surface area.

Reliability and validity of an accele-rometric system for assessing vertical jumping performance

The validity of an accelerometric system (Myotest©) for assessing vertical jump height, vertical force and power, leg stiffness and reactivity index was examined. 20 healthy males performed 3ד5 hops in place”, 3ד1 squat jump” and 3× “1 countermovement jump” during 2 test-retest sessions. The variables were simultaneously assessed using an accelerometer and a force platform at a frequency of 0.5 and 1 kHz, respectively. Both reliability and validity of the accelerometric system were studied. No significant differences between test and retest data were found (p < 0.05), showing a high level of reliability. Besides, moderate to high intraclass correlation coefficients (ICCs) (from 0.74 to 0.96) were obtained for all variables whereas weak to moderate ICCs (from 0.29 to 0.79) were obtained for force and power during the countermovement jump. With regards to validity, the difference between the two devices was not significant for 5 hops in place height (1.8 cm), force during squat (-1.4 N · kg⁻¹) and countermovement (0.1 N · kg⁻¹) jumps, leg stiffness (7.8 kN · m⁻¹) and reactivity index (0.4). So, the measurements of these variables with this accelerometer are valid, which is not the case for the other variables. The main causes of non-validity for velocity, power and contact time assessment are temporal biases of the takeoff and touchdown moments detection.

A randomised clinical study to evaluate experimental children's toothpastes in an in-situ palatal caries model in children aged 11-14 years

OBJECTIVES

To compare three children's sodium fluoride toothpastes to placebo with respect to enamel remineralisation potential, enamel fluoride uptake and net acid resistance using an in situ palatal caries model in children aged 11-14 years following a single brushing.

DESIGN

This was a randomised, single blind (laboratory analyst), single-centre, four-treatment, crossover study with a 7-day washout period between treatments. The treatments were 1,426 ppm fluoride, 1,000 ppm fluoride, 500 ppm fluoride and 0 ppm fluoride (placebo) toothpaste (NaF/silica). A custom made in situ palatal appliance was used by each subject in all treatment periods. At each of the four treatment visits subjects wore the appliance containing four partially demineralised human enamel specimens for 5 minutes and then brushed their teeth using a standardised procedure for 60 seconds under supervision using 1.0 g (±0.1 g) of their assigned toothpaste. After 4 hours the appliance was removed and enamel specimen recovered. This process was repeated until all subjects completed all four study treatment visits. Recovered enamel specimens were analysed for per cent surface microhardness recovery (%SMHR; Knoop) and enamel fluoride uptake (EFU; microdrill biopsy). Subsequently, specimens were demineralised in vitro to determine their % net acid resistance (%NAR; Knoop).

RESULTS

All three fluoride toothpastes demonstrated significantly greater %SMHR, EFU and %NAR compared with 0 ppm F toothpaste. The model demonstrated a dose response over the range 0 to 1,426 ppm fluoride for %SMHR, EFU and %NAR. There was no significant difference between 500 ppm F and 1,000 ppm F for %SMHR and between 1,000 ppm F and 1,426 ppm F for %SMHR, EFU and %NAR.

CONCLUSIONS

The present in situ study demonstrated that the children's fluoride toothpastes tested are capable of delivering cariostatic amounts of fluoride to early caries lesions following a single brushing.

Semisynthetic model calibration for monitoring glucose in mammalian cell culture with in situ near infrared spectroscopy

Near infrared (NIR) spectroscopy has the capability of providing real-time, multi-analyte monitoring of the complex reaction mixture associated with cell culture processes. However, the development of robust models to predict the concentration of key analytes has proven difficult. In this study, a modeling methodology using semisynthetic process samples was used to predict glucose concentrations in Chinese Hamster Ovary (CHO) cell culture processes. Partial Least Squares (PLS) regression models were built from in situ NIR spectra, and glucose levels between 4.0 and 14.0 g/L. Two models were constructed. The "standard model" used data provided by cell culture production process samples. The "full model" included the data provided from both cell culture production process samples and semisynthetic samples. The semisynthetic samples were generated by titrating cell culture samples with target viable cell density (VCD) and lactate levels to defined glucose concentrations. The robustness of each model was gauged by predicting glucose in a subsequent cell culture process utilizing a media formulation and cell line not contained in the calibration data sets. The "full model" generated glucose predictions with a root mean square error of prediction (RMSEP) of 0.99 g/L while the "standard model" provided glucose predictions with a RMSEP of 2.26 g/L. The modeling approach utilizing semisynthetic samples proved to be faster development and more effective than using just standard cell culture processes.

In-situ studies of cartilage microtribology: roles of speed and contact area

The progression of local cartilage surface damage toward early stage osteoarthritis (OA) likely depends on the severity of the damage and its impact on the local lubrication and stress distribution in the surrounding tissue. It is difficult to study the local responses using traditional methods; in-situ microtribological methods are being pursued here as a means to elucidate the mechanical aspects of OA progression. While decades of research have been dedicated to the macrotribological properties of articular cartilage, the microscale response is unclear. An experimental study of healthy cartilage microtribology was undertaken to assess the physiological relevance of a microscale friction probe. Normal forces were on the orderof50 mN. Sliding speed varied from 0 to 5 mm/s, and two probes radii, 0.8 mm and 3.2 mm, were used in the study. In-situ measurements of the indentation depth into the cartilage enabled calculations of contact area, effective elastic modulus, elastic and fluid normal force contributions, and the interfacial friction coefficient. This work resulted in the following findings: 1) at high sliding speed (V=1-5 mm/s), the friction coefficient was low (μ = 0.025) and insensitive to probe radius (0.8 mm 3.2 mm) despite the 4-folddifference in the resulting contact areas; 2) The contact area was a strong function of the probe radius and sliding speed; 3) the friction coefficient was proportional to contact area when sliding speed varied from 0.05mm/s-5mm/s; 4) the fluid load support was greater than 85% for all sliding conditions (0% fluid support when V=0) and was insensitive to both probe radius and sliding speed. The findings were consistent with the adhesive theory of friction; as speed increased, increased effective hardness reduced the area of solid-solid contact which subsequently reduced the friction force. Where the severity of the sliding conditions dominates the wear and degradation of typical engineering tribomaterials, the results suggest that joint motion is actually beneficial for maintaining low matrix stresses, low contact areas, and effective lubrication for the fluid-saturated porous cartilage tissue. Further, the results demonstrated effective pressurization and lubrication beneath single asperity microscale contacts. With carefully designed experimental conditions, local friction probes can facilitate more fundamental studies of cartilage lubrication, friction and wear, and potentially add important insights into the mechanical mechanisms of OA.