High-Power Quantum Cascade Lasers Emitting at 8 µm: Technology and Analysis.

In this work, we demonstrate the features of a two-stage epitaxial growth technique and show the results of power and efficiency measurements for three different designs of quantum cascade lasers with a record-high peak power in the 8 µm spectral region. The time-resolved QCL spectral study proves that InP-based upper cladding paired with an InP contact layer provides better heat dissipation and allows one to reach better power characteristics in comparison with InGaAs-based contact, even with short pulse pumping.

Trace element fractions in sediments of urbanised lakes of the arctic zone of Russia.

This paper presents the comprehensive evaluation of the level of accumulation of some of the most dangerous environmental pollutants (V, Co, Sn, Ni, Cr, Mn, Cd, Cu, Pb, Sb, Zn) and analyses their chemical forms in sediments of four small lakes located within Murmansk urban territory. Furthermore, the authors first studied morphology and chemical composition of industrial dust collected from the snow covering the ice of Lake Srednee. Fieldwork was carried out in April 2019. The results showed that sediments of the Murmansk urban lakes are significantly enriched in the content of the toxic metals and metalloids Cd, Pb, Sb, Zn, Cu, V, and Ni. An integrated assessment of anthropogenic impact using the pollution load index (PLI) and geoaccumulation index (Igeo) revealed a moderate to the extremely strong pollution level in recent sediment layers. The analysis of the fractions of the elements showed that they are mainly associated with stable compounds, such as primary minerals or persistent technogenic compounds (slag, matte, and dust). However, humic substances are a significant accumulative matrix for most studied elements. The share of the most mobile fractions does not exceed 30% for the vast majority of elements, even in the most polluted layers. The accumulation of the major part of pollutants can be attributed to the activities of the main industrial objects of the city (thermal power plant, coal port, transport infrastructure), and the impact of the global atmospheric transport of pollutants to the Arctic regions of Russia.

Donor-Acceptor Bicyclopropyls as 1,6-Zwitterionic Intermediates: Synthesis and Reactions with 4-Phenyl-1,2,4-triazoline-3,5-dione and Terminal Acetylenes.

The bicyclopropyl system activated by incorporation of donor and acceptor groups in the presence of Lewis acids was used as a synthetic equivalent of 1,6-zwitterions. Opening of both cyclopropane rings in 2'-aryl-1,1'-bicyclopropyl-2,2-dicarboxylates (D-A bicyclopropyl, ABCDs) in the presence of GaI3 + Bu4N+GaI4- results in 5-iodo-5-arylpent-2-enylmalonates as products of HI formal 1,6-addition to the bicyclopropyl system. The use of GaCl3 or GaBr3 as a Lewis acid and terminal aryl or alkyl acetylenes as 1,6-zwitterion interceptors allows the alkyl substituent to be grown to give the corresponding acyclic 7-chloro(bromo)-hepta-2,6-dienylmalonates. The reaction of ABCDs with 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) catalyzed by Yb(OTf)3 also results in the opening of both cyclopropane rings. The reaction products are tetrahydropyridazine derivatives - (7,9-dioxo-1,6,8-triazabicyclo[4.3.0]non-3-en-2-ylmethyl)malonates - containing one more PTAD moiety in the malonyl group.

The crowding dynamics of the motor protein kinesin-II.

Intraflagellar transport (IFT) in C. elegans chemosensory cilia is an example of functional coordination and cooperation of two motor proteins with distinct motility properties operating together in large groups to transport cargoes: a fast and processive homodimeric kinesin-2, OSM-3, and a slow and less processive heterotrimeric kinesin-2, kinesin-II. To study the mechanism of the collective dynamics of kinesin-II of C. elegans cilia in an in vitro system, we used Total Internal Reflection Fluorescence microscopy to image the motility of truncated, heterodimeric kinesin-II constructs at high motor densities. Using an analysis technique based on correlation of the fluorescence intensities, we extracted quantitative motor parameters, such as motor density, velocity and average run length, from the image. Our experiments and analyses show that kinesin-II motility parameters are far less affected by (self) crowding than OSM-3. Our observations are supported by numerical calculations based on the TASEP-LK model (Totally Asymmetric Simple Exclusion Process-Langmuir Kinetics). From a comparison of data and modelling of OSM-3 and kinesin-II, a general picture emerges of the collective dynamics of the kinesin motors driving IFT in C. elegans chemosensory cilia and the way the motors deal with crowding.

On interevent time distributions of avalanche dynamics.

Physical systems characterized by stick-slip dynamics often display avalanches. Regardless of the diversity of their microscopic structure, these systems are governed by a power-law distribution of avalanche size and duration. Here we focus on the interevent times between avalanches and show that, unlike their distributions of size and duration, the interevent time distributions are able to distinguish different mechanical states of the system. We use experiments on granular systems and numerical simulations of emulsions to show that systems having the same probability distribution for avalanche size and duration can have different interevent time distributions. Remarkably, these interevent time distributions look similar to those for earthquakes and, if different from an exponential, are indirect evidence of non trivial space-time correlations among avalanches. Our results therefore indicate that interevent time statistics are essential to characterise the dynamics of avalanches.

Experience in Developing an FHIR Medical Data Management Platform to Provide Clinical Decision Support.

This paper is an extension of work originally presented to pHealth 2019-16th International Conference on Wearable, Micro and Nano Technologies for Personalized Health. To provide an efficient decision support, it is necessary to integrate clinical decision support systems (CDSSs) in information systems routinely operated by healthcare professionals, such as hospital information systems (HISs), or by patients deploying their personal health records (PHR). CDSSs should be able to use the semantics and the clinical context of the data imported from other systems and data repositories. A CDSS platform was developed as a set of separate microservices. In this context, we implemented the core components of a CDSS platform, namely its communication services and logical inference components. A fast healthcare interoperability resources (FHIR)-based CDSS platform addresses the ease of access to clinical decision support services by providing standard-based interfaces and workflows. This type of CDSS may be able to improve the quality of care for doctors who are using HIS without CDSS features. The HL7 FHIR interoperability standards provide a platform usable by all HISs that are FHIR enabled. The platform has been implemented and is now productive, with a rule-based engine processing around 50,000 transactions a day with more than 400 decision support models and a Bayes Engine processing around 2000 transactions a day with 128 Bayesian diagnostics models.

Three-Component GaHal3-Promoted Reactions of Substituted Methylidenemalonates and Donor-Acceptor Cyclopropanes with Propargyl Halides: Cascade Diastereoselective Construction of Five-Membered Lactones.

A new cascade three-component process for high trans,trans-diastereoselective assembly of five-membered (1-halovinyl)lactones has been developed. The process is based on reactions of substituted methylidenemalonates and cyclopropanedicarboxylates with 3-haloprop-1-ynes in the presence of GaHal3 and involves the intermediate in situ generation of 1,2-zwitterionic gallium complexes with [Ga(L)3]3+[GaX4-]3 composition. Chloro, bromo, and iodo derivatives can be obtained successfully. Mechanistic and stereochemical aspects of the process we developed have been studied and considered in detail.

Ionic Ga-Complexes of Alkylidene- and Arylmethylidenemalonates and Their Reactions with Acetylenes: An In-Depth Look into the Mechanism of the Occurring Gallium Chemistry.

A new synthetic concept was suggested in the chemistry of substituted methylidenemalonates that enables their utilization as 1,2-zwitterionic synthons. This strategy is to generate liquid ionic Ga complexes from methylidenemalonates and GaHal3 with a strict 3/4 composition and then use them in further synthesis. A number of complexes with different metal halides have been synthesized and studied in detail. The unique properties of gallium among all metals have been demonstrated and explained. On the basis of the discovered new class of gallium complexes of methylidenemalonates, a number of novel reactions with acetylenes have been elaborated, which are unknown in the conventional chemistry of methylidenemalonates. The main demonstrated process is a three-component addition to a triple bond involving halide anions, leading to the formation of polyfunctional vinyl halides with high E-selectivity. The mechanism has been studied experimentally in fine detail. Application of specially optimized 71Ga NMR spectroscopy makes it possible to take an in-depth look into the gallium chemistry in a new light. In particular, the key participation of GaHal4- anions in the occurring transformations has been established.

Optimization of the optical coupling in nanowire-based integrated photonic platforms by FDTD simulation.

The optimized design of a photonic platform based on a nanowire light emitting diode (LED) and a nanowire photodetector connected with a waveguide is proposed. The light coupling efficiency from the LED to the detector is optimized as a function of the geometrical parameters of the system using the finite difference time domain simulation tool Lumerical. Starting from a design reported in the literature with a coupling efficiency of only 8.7%, we propose an optimized photonic platform with efficiency reaching 65.5%.

Patients Decision Aid System Based on FHIR Profiles.

Patients are becoming more and more involved in clinical decision-making process. Several factors support this process. Advances in omics allows individualization of diagnosis and treatment. Patient awareness and easy availability of data on the Internet allows patients to become informed decision makers when it comes even to disease management. Mass media emphasize the issue of medical errors, making patients demanding for quality in medical care. In some healthcare settings, patents face a problem of interpreting medical data and making decisions on treatment tactics without having a doctor, who could potentially support them. Delegating this task to a Patient Decision Aide system can add automatically generated recommendations to result reports without adding significant workload on the doctors, increase patients' motivation and support their decisions. We have implemented a patient decision aid system based on the productions rules, which: Collects data from available sources; Automatically analyses and interprets laboratory test results; Recommends running additional tests for a more precise diagnostic; Delivers automatically generated reports to doctors and patients in a natural language. To achieve semantic interoperability with other systems we have implemented a FHIR engine. The knowledge base has been organized as a graph structure. The application is structured as a set of lightly coupled services, which implement the logic of the decision support system. In total, we have modelled 365 nodes of test components, 5084 nodes of inference rules, 49932 connections and 3072 blocks of text for medical certificates. The findings of the research provide a deep understanding of how the semantically interoperable clinical decision support systems are implemented. Advances in notification the patients with the elements of patient decision aid is important for clinical data management, and for patients' empowerment and protection. We suppose that the system empowering patients in such way can play a meaningful role in helping patients to make informed decisions during the process of diagnostics and treatment.

Cascade Cleavage of Three-Membered Rings in the Reaction of D-A Cyclopropanes with 4,5-Diazaspiro[2.4]hept-4-enes: A Route to Highly Functionalized Pyrazolines.

A new cascade process for reactions of donor-acceptor cyclopropanes (DACs) with spiro[cyclopropanepyrazolines] in the presence of EtAlCl2 or Ga halides is reported. The action of a Lewis acid results in DAC activation and addition of the carbocationic intermediate to the azocyclopropane system of the pyrazoline with opening of the second three-membered ring and addition of a halide anion from the Lewis acid. A specific feature of this process is that one activated cyclopropane ring activates another one, and depending on the component ratio, the process can involve two DAC molecules and one pyrazoline molecule or one DAC molecule and two pyrazoline molecules. The process is tolerant to various functional groups and occurs with a wide range of substrates to give polyfunctionalized structures based on a 2-pyrazoline moiety.

Selected aspects of the current state of freshwater resources in the Murmansk region, Russia.

Aspects of reducing the resource potential of surface waters of the Murmansk region in the global climate change and the environment and their irrational use have been considered. Increase of aquatic environment toxicity, drastic restructuring of the structural and functional characteristics of aquatic communities, changes in trophic status of lakes, reducing the stability of freshwater ecosystems, increasing the risk of catastrophic degradation have been shown. Taking into account the regional peculiarities, some indicators of surface water quality in the Murmansk region have been proposed.

Universal slip dynamics in metallic glasses and granular matter - linking frictional weakening with inertial effects.

Slowly strained solids deform via intermittent slips that exhibit a material-independent critical size distribution. Here, by comparing two disparate systems - granular materials and bulk metallic glasses - we show evidence that not only the statistics of slips but also their dynamics are remarkably similar, i.e. independent of the microscopic details of the material. By resolving and comparing the full time evolution of avalanches in bulk metallic glasses and granular materials, we uncover a regime of universal deformation dynamics. We experimentally verify the predicted universal scaling functions for the dynamics of individual avalanches in both systems, and show that both the slip statistics and dynamics are independent of the scale and details of the material structure and interactions, thus settling a long-standing debate as to whether or not the claim of universality includes only the slip statistics or also the slip dynamics. The results imply that the frictional weakening in granular materials and the interplay of damping, weakening and inertial effects in bulk metallic glasses have strikingly similar effects on the slip dynamics. These results are important for transferring experimental results across scales and material structures in a single theory of deformation dynamics.

[4 + 2] Annulation of Donor-Acceptor Cyclopropanes with Acetylenes Using 1,2-Zwitterionic Reactivity.

A new process for the [4 + 2] annulation of donor-acceptor cyclopropanes with acetylenes under the effect of anhydrous GaCl3 using 1,2-zwitterion reactivity was elaborated. The reaction opens access to substituted dihydronaphthalenes, naphthalenes, and other fused carbocycles. The direction of the reaction can be efficiently controlled by temperature.

Universal Quake Statistics: From Compressed Nanocrystals to Earthquakes.

Slowly-compressed single crystals, bulk metallic glasses (BMGs), rocks, granular materials, and the earth all deform via intermittent slips or "quakes". We find that although these systems span 12 decades in length scale, they all show the same scaling behavior for their slip size distributions and other statistical properties. Remarkably, the size distributions follow the same power law multiplied with the same exponential cutoff. The cutoff grows with applied force for materials spanning length scales from nanometers to kilometers. The tuneability of the cutoff with stress reflects "tuned critical" behavior, rather than self-organized criticality (SOC), which would imply stress-independence. A simple mean field model for avalanches of slipping weak spots explains the agreement across scales. It predicts the observed slip-size distributions and the observed stress-dependent cutoff function. The results enable extrapolations from one scale to another, and from one force to another, across different materials and structures, from nanocrystals to earthquakes.

Sharp symmetry-change marks the mechanical failure transition of glasses.

Glasses acquire their solid-like properties by cooling from the supercooled liquid via a continuous transition known as the glass transition. Recent research on soft glasses indicates that besides temperature, another route to liquify glasses is by application of stress that drives relaxation and flow. Here, we show that unlike the continuous glass transition, the failure of glasses to applied stress occurs by a sharp symmetry change that reminds of first-order equilibrium transitions. Using simultaneous x-ray scattering during the oscillatory rheology of a colloidal glass, we identify a sharp symmetry change from anisotropic solid to isotropic liquid structure at the crossing of the storage and loss moduli. Concomitantly, intensity fluctuations sharply acquire Gaussian distributions characteristic of liquids. Our observations and theoretical framework identify mechanical failure as a sharp atomic affine-to-nonaffine transition, providing a new conceptual paradigm of the oscillatory yielding of this technologically important class of materials, and offering new perspectives on the glass transition.

Shear-induced breaking of cages in colloidal glasses: Scattering experiments and mode coupling theory.

We employ x-ray scattering on sheared colloidal suspensions and mode coupling theory to study structure factor distortions of glass-forming systems under shear. We find a transition from quadrupolar elastic distortion at small strains to quadrupolar and hexadecupolar modes in the stationary state. The latter are interpreted as signatures of plastic rearrangements in homogeneous, thermalized systems. From their transient evolution with strain, we identify characteristic strain and length-scale values where these plastic rearrangements dominate. This characteristic strain coincides with the maximum of the shear stress versus strain curve, indicating the proliferation of plastic flow. The hexadecupolar modes dominate at the wavevector of the principal peak of the equilibrium structure factor that is related to the cage-effect in mode coupling theory. We hence identify the structural signature of plastic flow of glasses.

Correlations of plasticity in sheared glasses.

In a recent paper [Mandal et al., Phys. Rev. E 88, 022129 (2013)], the nature of spatial correlations of plasticity in hard-sphere glasses was addressed both via computer simulations and in experiments. It was found that the experimentally obtained correlations obey a power law, whereas the correlations from simulations are better fitted by an exponential decay. We here provide direct evidence-via simulations of a hard-sphere glass in two dimensions (2D)-that this discrepancy is a consequence of the finite system size in the 3D simulations. By extending the study to a 2D soft disk model at zero temperature [Durian, Phys. Rev. Lett. 75, 4780 (1995)], the robustness of the power-law decay in sheared amorphous solids is underlined. Deviations from a power law occur when either reducing the packing fraction towards the supercooled regime in the case of hard spheres or changing the dissipation mechanism from contact dissipation to a mean-field-type drag in the case of soft disks.

Chemical composition of lake sediments along a pollution gradient in a Subarctic watercourse.

Sediment cores were collected from seven lakes in the Subarctic Pasvik watercourse, polluted by sewage waters and air emissions from the Pechenganickel Metallurgical Company, in order to study chemical composition and estimate the intensity of pollution by taking into account background concentration of elements and the vertical and spatial distribution of their contents in cores and surficial layers of sediments. Sediment samples were analysed by atomic-absorption spectrophotometry for 18 elements (Ni, Cu, Co, Zn, Cd, Pb, Hg, As, Cr, Sr, Mn, Fe, Ca, Mg, Na, K, Al, P). Maximum concentrations of all investigated heavy metals (Ni, Cu, Co, Zn, Cd, Pb, Hg, As) were found in the surficial sediment layers of Lake Kuetsjarvi situated directly below the metallurgic smelters. Decreased contents of heavy metals were observed in surficial sediment layers further downstream in the Pasvik watercourse, although pollution remained rather high. Considerable increase in the contents of the heavy metals emitted into the atmosphere in significant amounts by the Pechenganickel Company (Ni, Cu, Co, Zn), was not observed in surficial sediment layers of lakes upstream in the watercourse polluted only by air contamination and household sewage, but substantial increase of the concentrations of chalcophile elements (Pb, Cd, Hg, As) was revealed. The increase in P contents towards the sediment surface in some lakes may suggest a development of eutrophication processes. Our studies reveal that the metallurgic processing of the Pechenganickel Company has resulted in comprehensive heavy metal pollution and contaminations of lakes sediments in the Inari-Pasvik watercourse. The pollution impact on the sediments is most severe in Lake Kuetsjarvi in the vicinity of the smelters, intermediate in lake localities in the main watercourse downstream the metallurgic enterprises and least in lake localities in the upstream part of the watercourse.