Computer-assisted arthroplasty using bioengineered autografts.

Recent advances in tissue-engineered cartilage open the door to new clinical treatments of joint lesions. Common to all therapies with in-vitro-engineered autografts is the need for optimal fit of the construct to allow screwless implantation and optimal integration into the live joint. Computer-assisted surgery (CAS) techniques are prime candidates to ensure the required accuracy, while at the same time simplifying the procedure. A pilot study has been conducted aiming at assembling a new set of methods to support ankle joint arthroplasty using bioengineered autografts. Computer assistance allows planning of the implant shape on a computed tomography (CT) image, manufacturing the construct according to the plan, and interoperatively navigating the surgical tools for implantation. A rotational symmetric model of the joint surface was used to avoid segmentation of the CT image; new software was developed to determine the joint axis and make the implant shape parameterizable. A complete cycle of treatment from planning to operation was conducted on a human cadaveric foot, thus proving the feasibility of computer-assisted arthroplasty using bioengineered autografts.     

Classrooms' indoor environmental conditions affecting the academic achievement of students and teachers in higher education: A systematic literature review

This study reports the outcomes of a systematic literature review, which aims to determine the influence of four indoor environmental parameters — indoor air, thermal, acoustic, and lighting conditions —on the quality of teaching and learning and on students' academic achievement in schools for higher education, defined as education at a college or university. By applying the Cochrane Collaboration Method, relevant scientific evidence was identified by systematically searching in multiple databases. After the screening process, 21 publications of high relevance and quality were included. The collected evidence showed that the indoor environmental quality (IEQ) can contribute positively to the quality of learning and short-term academic performance of students. However, the influence of all parameters on the quality of teaching and the long-term academic performance could not be determined yet. Students perform at their best in different IEQ conditions, and these conditions are task-dependent, suggesting that classrooms which provide multiple IEQ classroom conditions facilitate different learning tasks optimally. In addition, the presented evidence illuminates how to examine the influence of the IEQ on users. Finally, this information supports decision-makers in facility management and building systems engineering to improve the IEQ, and by doing so, allow teachers and students to perform optimally.     

Dipeptidyl Enoates As Potent Rhodesain Inhibitors That Display a Dual Mode of Action

Dipeptidyl enoates were prepared through a high‐yielding two‐step synthetic route. They have a dipeptidic structure with a 4‐oxoenoate moiety as a warhead with multiple reactive sites. Dipeptidyl enoates were screened against rhodesain and human cathepsins B and L, and were found to be potent and selective inhibitors of rhodesain. Among them (S,E)‐ethyl 5‐((S)‐2‐{[(benzyloxy)carbonyl]amino}‐3‐phenylpropanamido)‐7‐methyl‐4‐oxooct‐2‐enoate ( 6 ) was the most potent, with an IC₅₀ value of 16.4 nM and k_inact/K_i=1.6×10⁶ M ^?1 s^?1 against rhodesain. These dipeptidyl enoates display a reversible mode of inhibition at very low concentrations and an irreversible mode at higher concentrations. Inhibition kinetics data, supported by docking studies, suggest a dual mode of action via attack of cysteine thiolate at two reactive positions.     

Synthesis and Pharmacological Properties of Silicon‐Containing GPR81 and GPR109A Agonists

The GPR81 and GPR109A receptors mediate antilipolytic effects and are potential drug targets for the treatment of metabolic disorders such as dyslipidemia and type 2 diabetes. There is still a need to identify potent GPR81 agonists as pharmacological tools. A high‐throughput screen identified an acylurea‐based GPR81 agonist lead series, with activities at the GPR109A receptor as well. To expand the chemical scope and to explore the pharmacological and pharmacokinetic consequences, a series of structurally related organosilicon compounds with a 6‐sila‐4,5,6,7‐tetrahydrobenzo[d]thiazole skeleton was synthesized and studied for their physicochemical properties [octanol/water distribution coefficient (pH 7.4), solubility in HBSS buffer (pH 7.4)], agonistic potency at rat GPR81 and GPR109A receptors, and intrinsic clearance in human liver microsomes and rat hepatocytes. The straightforward synthesis of these organosilicon compounds offered a valuable expansion of the chemical scope in the above‐mentioned GPR81 agonist lead series, provided potency and efficacy SAR, and yielded compounds with sub‐micromolar GPR81 potency. This work supports the value of including silicon chemistry into the toolbox of medicinal chemistry.     

Writing Silica Structures in Liquid with Scanning Transmission Electron Microscopy

Silica nanoparticles are imaged in solution with scanning transmission electron microscopy (STEM) using a liquid cell with silicon nitride (SiN) membrane windows. The STEM images reveal that silica structures are deposited in well‐defined patches on the upper SiN membranes upon electron beam irradiation. The thickness of the deposits is linear with the applied electron dose. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrate that the deposited patches are a result of the merging of the original 20 nm‐diameter nanoparticles, and that the related surface roughness depends on the electron dose rate used. Using this approach, sub‐micrometer scale structures are written on the SiN in liquid by controlling the electron exposure as function of the lateral position.     

Organic Thin Film Transistors Based on Highly Dipolar Donor–Acceptor Polymethine Dyes

Organic thin film transistors (OTFTs) of a series of twenty dipolar donor–acceptor‐substituted polymethine dyes (D–A dyes, dipole moments from 3–15 D) are investigated. The employed merocyanine dyes contain a dimethine bridge that is substituted with 1‐alkyl‐3,3‐dimethylindolin‐2‐ylidene (“Fischer base”), 3‐alkyl‐2,3‐dihydrobenzothiazol‐2‐ylidene or 1,3‐benzodithiole‐2‐ylidene, respectively, as electron‐donating unit and various acceptor heterocycles. These studies show that thin films formed by these D–A dyes upon deposition in high vacuum are all composed of antiparallel π‐stacked dimers. However, they are either amorphous, discontinuous or highly crystalline due to the interplay between molecule‐substrate and dimer–dimer interactions. With the help of single crystal X‐ray analysis, out‐of‐plane X‐ray studies (XRD), selected area electron diffraction (SAED), and atomic force microscopy (AFM), a correlation between the molecular structure, film ordering, and hole charge transport ability can be established. The mobility values are compared to Bässler's disorder charge transport theory and a film growth mechanism is proposed based on DFT calculations and single crystal structures. The results show that with carefully adjusted bulky substituents and high dipolarity an intimate centrosymmetric packing with a slipped, but tight π‐stacking arrangement could be realized. This provides two‐dimensional percolation pathways for holes and ultimately results in charge carrier mobilities up to 0.18 cm² V^?1 s^?1.     

Entwicklung eines Ionisationsmanometers mit Feldemitterkathode

Development of an ion gauge with field emissionin cryogenic vacuum environments cathode for pressure measurements The measurement of UHV or even XHV pressures in low‐temperature vacuum systems has always been considered as a metrological problem. In principle, conventional hot‐cathode ion gauges can be used for pressure measurement in cryogenic vacuum environments. However, as a consequence of their high heat generation several disadvantages must be taken into account. With the development of an ion gauge of extractor‐type whose heat‐generating thermionic cathode is replaced by a non‐thermal field emission cathode, a promising approach to realize a reliable pressure gauge for cryogenic vacuum applications can be presented in this paper. The gauge equipped with a CNT cathode was investigated both experimentally and by numerical simulations in terms of their operating characteristics. It has been successfully demonstrated that the modified extractor gauge works reliably under low temperature conditions and provides meaningful pressure readings.     

Simulation‐Experimental Approach to Investigate the Role of Interfaces in Self‐Replenishing Composite Coatings

To investigate self‐replenishing on surface‐structured composite coatings a dual simulation‐experimental approach is employed to study the decisive role of polymer‐air and polymer‐particle interfaces. Experimentally, the composite system consists of a cross‐linked polymer network with fluorinated‐dangling chains, embedding colloidal SiO₂ nanoparticles which are incorporated in the network via covalent bonding. These particles provide the desired surface structure at the air‐interface before and after damage. Any damage replicates the rough surface, while the polymer layer on top of the particles serves as source of low surface energy groups which are able to reorient towards the new air‐interfaces. Using coarse‐grained simulations details of these self‐replenishing composite systems are revealed such as the minimum thickness of the polymer layer necessary for providing optimal self‐replenishing ability and the distribution profile of the dangling chains at the various interfaces. The principles and dual approach reported here may be applied to other self‐healing composite systems with applications in self‐cleaning, anti‐fouling or low adhesion materials.