The seventh blind test of crystal structure prediction: structure generation methods.

A seventh blind test of crystal structure prediction was organized by the Cambridge Crystallographic Data Centre featuring seven target systems of varying complexity: a silicon and iodine-containing molecule, a copper coordination complex, a near-rigid molecule, a cocrystal, a polymorphic small agrochemical, a highly flexible polymorphic drug candidate, and a polymorphic morpholine salt. In this first of two parts focusing on structure generation methods, many crystal structure prediction (CSP) methods performed well for the small but flexible agrochemical compound, successfully reproducing the experimentally observed crystal structures, while few groups were successful for the systems of higher complexity. A powder X-ray diffraction (PXRD) assisted exercise demonstrated the use of CSP in successfully determining a crystal structure from a low-quality PXRD pattern.

Machine Learning Classification of Local Environments in Molecular Crystals.

Identifying local structural motifs and packing patterns of molecular solids is a challenging task for both simulation and experiment. We demonstrate two novel approaches to characterize local environments in different polymorphs of molecular crystals using learning models that employ either flexibly learned or handcrafted molecular representations. In the first case, we follow our earlier work on graph learning in molecular crystals, deploying an atomistic graph convolutional network combined with molecule-wise aggregation to enable per-molecule environmental classification.

Human In Vitro Models of Neuroenergetics and Neurometabolic Disturbances: Current Advances and Clinical Perspectives.

Neurological conditions conquer the world; they are the leading cause of disability and the second leading cause of death worldwide, and they appear all around the world in every age group, gender, nationality, and socioeconomic class. Despite the growing evidence of an immense impact of perturbations in neuroenergetics on overall brain function, only little is known about the underlying mechanisms. Especially human insights are sparse, owing to a shortage of physiologically relevant model systems.

Controlling crystallization: what liquid structure and dynamics reveal about crystal nucleation mechanisms.

Over recent years, molecular simulations have provided invaluable insights into the microscopic processes governing the initial stages of crystal nucleation and growth. A key aspect that has been observed in many different systems is the formation of precursors in the supercooled liquid that precedes the emergence of crystalline nuclei. The structural and dynamical properties of these precursors determine to a large extent the nucleation probability as well as the formation of specific polymorphs.

Geometric Deep Learning for Molecular Crystal Structure Prediction.

We develop and test new machine learning strategies for accelerating molecular crystal structure ranking and crystal property prediction using tools from geometric deep learning on molecular graphs. Leveraging developments in graph-based learning and the availability of large molecular crystal data sets, we train models for density prediction and stability ranking which are accurate, fast to evaluate, and applicable to molecules of widely varying size and composition. Our density prediction model, MolXtalNet-D, achieves state-of-the-art performance, with lower than 2% mean absolute error on a large and diverse test data set.

Developer's Guide to an Organ-on-Chip Model.

Over the past decade, organ-on-chip research has been one of the most prolific areas of the entire field of tissue engineering. The development of organ-on-chip models requires an integrated interdisciplinary approach merging technologies and concepts from several different disciplines, including microfabrication, microfluidics, biomaterials, stem cell science, pharma-/toxicology, and medicine. In this perspective, we follow the journey of an organ-on-chip through its many different stages, from (i) the initial idea/specific scientific question to (ii) the design/concept phase, (iii) the engineering (fabrication and materials, sensor/actuator integration) and (iv) biology considerations (cell sources, biomaterials/scaffold), (v) the cell injection and tissue assembly process, (vi) the assay development, and (vii) the functional validation, all the way to (viii) the final applications.

Practical guide to replica exchange transition interface sampling and forward flux sampling.

Path sampling approaches have become invaluable tools to explore the mechanisms and dynamics of the so-called rare events that are characterized by transitions between metastable states separated by sizable free energy barriers. Their practical application, in particular to ever more complex molecular systems, is, however, not entirely trivial. Focusing on replica exchange transition interface sampling (RETIS) and forward flux sampling (FFS), we discuss a range of analysis tools that can be used to assess the quality and convergence of such simulations, which is crucial to obtain reliable results.

Template-Induced Precursor Formation in Heterogeneous Nucleation: Controlling Polymorph Selection and Nucleation Efficiency.

We present an atomistic study of heterogeneous nucleation in Ni employing transition path sampling, which reveals a template precursor-mediated mechanism of crystallization. Most notably, we find that the ability of tiny templates to modify the structural features of the liquid and promote the formation of precursor regions with enhanced bond-orientational order is key to determining their nucleation efficiency and the polymorphs that crystallize. Our results reveal an intrinsic link between structural liquid heterogeneity and the nucleating ability of templates, which significantly advances our understanding toward the control of nucleation efficiency and polymorph selection.

Autologous Human Immunocompetent White Adipose Tissue-on-Chip.

Obesity and associated diseases, such as diabetes, have reached epidemic proportions globally. In this era of "diabesity", white adipose tissue (WAT) has become a target of high interest for therapeutic strategies. To gain insights into mechanisms of adipose (patho-)physiology, researchers traditionally relied on animal models.

Interplay of structural and dynamical heterogeneity in the nucleation mechanism in nickel.

Gaining a fundamental understanding of crystal nucleation processes in metal alloys is crucial for the development and design of high-performance materials with targeted properties. Yet, crystallization is a complex non-equilibrium process and, despite having been studied for decades, the microscopic aspects that govern the crystallization mechanism of a material remain elusive to date. Recent evidence shows that the spatial heterogeneity in the supercooled liquid, characterised by extended regions with distinctive mobility and order, may be a key microscopic factor that determines the mechanism of crystal nucleation.

Peristaltic on-chip pump for tunable media circulation and whole blood perfusion in PDMS-free organ-on-chip and Organ-Disc systems.

Organ-on-chip (OoC) systems have become a promising tool for personalized medicine and drug development with advantages over conventional animal models and cell assays. However, the utility of OoCs in industrial settings is still limited, as external pumps and tubing for on-chip fluid transport are dependent on error-prone, manual handling. Here, we present an on-chip pump for OoC and Organ-Disc systems, to perfuse media without external pumps or tubing.

Isolation, Integration, and Culture of Human Mature Adipocytes Leveraging Organ-on-Chip Technology.

Research on white adipose tissue (WAT), which constitutes one-fifth to one-half of the total body mass of a human's body, has gained more and more interest and attention in the era of "diabesity". In vitro research on mature human WAT is hampered by many challenges and, hence, a majority of WAT-related research is conducted using animal models as well as clinical observations and genome-wide association studies (GWAS), both featuring limitations in terms of translatability and potential for experimental interventions, respectively. Here, we describe methods to isolate primary mature human adipocytes from biopsies and to fabricate tailored organ-on-chip platforms for the long-term culture of WAT constructs.

The Inflammatory Profile of Obesity and the Role on Pulmonary Bacterial and Viral Infections.

Obesity is a globally increasing health problem, entailing diverse comorbidities such as infectious diseases. An obese weight status has marked effects on lung function that can be attributed to mechanical dysfunctions. Moreover, the alterations of adipocyte-derived signal mediators strongly influence the regulation of inflammation, resulting in chronic low-grade inflammation.

Integration of Electrospun Membranes into Low-Absorption Thermoplastic Organ-on-Chip.

In recent years, organ-on-chip (OoC) systems have provoked increasing interest among researchers from different disciplines. OoCs enable the recreation of -like microenvironments and the generation of a wide range of different tissues or organs in a miniaturized way. Most commonly, OoC platforms are based on microfluidic modules made of polydimethylsiloxane (PDMS).

Trends in elastic properties of Ti-Ta alloys from first-principles calculations.

The martensitic start temperature () is a technologically fundamental characteristic of high-temperature shape memory alloys. We have recently shown [Chakraborty2016B224104] that the two key features in describing the composition dependence ofare the= 0 K phase stability and the difference in vibrational entropy which, within the Debye model, is directly linked to the elastic properties. Here, we use density functional theory together with special quasi-random structures to study the elastic properties of disordered martensite and austenite Ti-Ta alloys as a function of composition.

Role of pre-ordered liquid in the selection mechanism of crystal polymorphs during nucleation.

We investigate the atomistic mechanism of homogeneous nucleation during solidification in molybdenum employing transition path sampling. The mechanism is characterized by the formation of a pre-structured region of high bond-orientational order in the supercooled liquid followed by the emergence of the crystalline bulk phase within the center of the growing solid cluster. This precursor plays a crucial role in the process as it provides a diffusive interface between the liquid and crystalline core, which lowers the interfacial free energy and facilitates the formation of the bulk phase.

Identification of a multi-dimensional reaction coordinate for crystal nucleation in NiAl.

Nucleation during solidification in multi-component alloys is a complex process that comprises competition between different crystalline phases as well as chemical composition and ordering. Here, we combine transition interface sampling with an extensive committor analysis to investigate the atomistic mechanisms during the initial stages of nucleation in NiAl. The formation and growth of crystalline clusters from the melt are strongly influenced by the interplay between three descriptors: the size, crystallinity, and chemical short-range order of the emerging nuclei.

Safety and Efficacy of Non- and Minimally Irradiated Homologous Costal Cartilage in Primary and Revision Rhinoplasty.

Despite favorable results with conventionally irradiated homologous costal cartilage, there have been no clinical studies to date evaluating the utility of non- or minimally irradiated homologous costal cartilage (NIHCC) in rhinoplasty. To evaluate the safety and efficacy of NIHCC in primary and revision rhinoplasty. We conducted a retrospective medical record review of patients undergoing primary and revision rhinoplasty between January 2010 and December 2014.

Mechanism of collective interstitial ordering in Fe-C alloys.

Collective interstitial ordering is at the core of martensite formation in Fe-C-based alloys, laying the foundation for high-strength steels. Even though this ordering has been studied extensively for more than a century, some fundamental mechanisms remain elusive. Here, we show the unexpected effects of two correlated phenomena on the ordering mechanism: anharmonicity and segregation.

WAT-on-a-chip integrating human mature white adipocytes for mechanistic research and pharmaceutical applications.

Obesity and its numerous adverse health consequences have taken on global, pandemic proportions. White adipose tissue (WAT) - a key contributor in many metabolic diseases - contributes about one fourth of a healthy human's body mass. Despite its significance, many WAT-related pathophysiogical mechanisms in humans are still not understood, largely due to the reliance on non-human animal models.

Advanced gelatin-based vascularization bioinks for extrusion-based bioprinting of vascularized bone equivalents.

Bone tissue is highly vascularized. The crosstalk of vascular and osteogenic cells is not only responsible for the formation of the strongly divergent tissue types but also for their physiological maintenance and repair. Extrusion-based bioprinting presents a promising fabrication method for bone replacement.