Experimental and computational evaluation of knee implant wear and creep under in vivo and ISO boundary conditions.

Background: Experimental knee implant wear testing according to ISO 14243 is a standard procedure, but it inherently possesses limitations for preclinical evaluations due to extended testing periods and costly infrastructure. In an effort to overcome these limitations, we hereby develop and experimentally validate a finite-element (FE)-based algorithm, including a novel cross-shear and contact pressure dependent wear and creep model, and apply it towards understanding the sensitivity of wear outcomes to the applied boundary conditions.

Methods: Specifically, we investigated the application of in vivo data for level walking from the publicly available "Stan" data set, which contains single representative tibiofemoral loads and kinematics derived from in vivo measurements of six subjects, and compared wear outcomes against those obtained using the ISO standard boundary conditions.

Cryogenic propellant management in space: open challenges and perspectives.

This paper presents open challenges and perspectives of propellant management for crewed deep space exploration. The most promising propellants are liquid hydrogen and liquid methane, together with liquid oxygen as an oxidizer. These fluids remain liquid only at cryogenic conditions, that is, at temperatures lower than 120 K.

The influence of implant design and limb alignment on in vivo wear rates of fixed-bearing and rotating-platform knee implant retrievals.

Analysis of polyethylene (PE) wear in knee implants is crucial for understanding the factors leading to revision in total knee arthroplasty. Importantly, current experimental and computational methods for predicting insert wear can only be validated against true in vivo measurements from retrievals. This study quantitatively investigated in vivo PE wear rates in fixed-bearing (FB) (n = 21) and rotating-platform (n = 53) implant retrievals.

Knee kinematics are primarily determined by implant alignment but knee kinetics are mainly influenced by muscle coordination strategy.

Implant malalignment has been reported to be a primary reason for revision total knee arthroplasty (TKA). In addition, altered muscle coordination patterns are commonly observed in TKA patients, which is thought to alter knee contact loads. A comprehensive understanding of the influence of surgical implantation and muscle recruitment strategies on joint contact mechanics is crucial to improve surgical techniques, increase implant longevity, and inform rehabilitation protocols.

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride.

Magnetic transition metal chalcogenides form an emerging platform for exploring spin-orbit driven Berry phase phenomena owing to the nontrivial interplay between topology and magnetism. Here we show that the anomalous Hall effect in pristine CrTe thin films manifests a unique temperature-dependent sign reversal at nonzero magnetization, resulting from the momentum-space Berry curvature as established by first-principles simulations. The sign change is strain tunable, enabled by the sharp and well-defined substrate/film interface in the quasi-two-dimensional CrTe epitaxial films, revealed by scanning transmission electron microscopy and depth-sensitive polarized neutron reflectometry.

A novel method to accurately recreate in vivo loads and kinematics in computational models of the knee.

Despite availability of knee loads and kinematics data, conventional load- and displacement-controlled configurations still can't accurately predict tibiofemoral loads from kinematics or vice versa. We propose a combined load- and displacement-control method for joint-level simulations of the knee to reliably reproduce contact mechanics. Prediction errors of the new approach were compared to those of conventional purely load- or displacement-controlled models using implant loads and kinematics for multiple subjects and activities (CAMS-Knee dataset).

SiOC Screens with Aligned and Adjustable Pore Structure for Screen Channel Liquid Acquisition Device.

The development of porous ceramic screens with high chemical stability, low density, and thermal conductivity can lead to promising screen channel liquid acquisition devices (SC-LADs) for propellant management under microgravity conditions in the future. Therefore, SiOC screens with aligned pores were fabricated via freeze-casting and applied as a SC-LAD. The pore window sizes and open porosity varied from 6 µm to 43 µm and 65% or 79%, depending on the freezing temperature or the solid loading, respectively.

European Society of Biomechanics S.M. Perren Award 2022: Standardized tibio-femoral implant loads and kinematics.

Knowledge of both tibio-femoral kinematics and kinetics is necessary for fully understanding knee joint biomechanics, guiding implant design and testing, and driving and validating computational models. In 2017, the CAMS-Knee datasets were presented, containing synchronized in vivo implant kinematics measured using a moving fluoroscope and tibio-femoral contact loads measured using instrumented implants from six subjects. However, to date, no representative summary of kinematics and kinetics obtained from measurements at the joint level of the same cohort of subjects exists.

Oblique saccades in internuclear ophthalmoplegia.

Oblique saccades often display component stretching, in which the shorter vector in one cardinal direction is slowed so that its duration matches that of the longer vector in the orthogonal direction, resulting in a straighter trajectory. In internuclear ophthalmoplegia, adducting saccades are typically slowed while vertical saccades are unaffected. It is not known whether these slowed adducting movements are accompanied by adaptive component stretching of the vertical vector during oblique saccades.

B-Doped δ-Layers and Nanowires from Area-Selective Deposition of BCl on Si(100).

Atomically precise, δ-doped structures forming electronic devices in Si have been routinely fabricated in recent years by using depassivation lithography in a scanning tunneling microscope (STM). While H-based precursor/monatomic resist chemistries for incorporation of donor atoms have dominated these efforts, the use of halogen-based chemistries offers a promising path toward atomic-scale manufacturing of acceptor-based devices. Here, B-doped δ-layers were fabricated in Si(100) by using BCl as an acceptor dopant precursor in ultrahigh vacuum.

Two case reports of acquired haemophilia A as complications of alemtuzumab treatment for multiple sclerosis.

Objective: To describe the case histories of two patients who developed acquired haemophilia A following treatment with alemtuzumab for multiple sclerosis.

Results: Two patients, a 48-year-old woman and a 31-year-old woman, developed acquired haemophilia A 21 months after their second doses of alemtuzumab. Both presented with spontaneous bruising, and the second case reported menorrhagia.

STM-Induced Desorption and Lithographic Patterning of Cl-Si(100)-(2 × 1).

A scanning tunneling microscope (STM) was used to investigate tip-induced chlorine desorption and lithographic patterning of Cl-terminated Si(100)-(2 × 1) surfaces from 4 to 600 K in ultrahigh vacuum. Until now, STM lithography has exclusively focused on hydrogen-based chemistry for donor device fabrication. As the initial step in developing halogen-based chemistries for STM fabrication of acceptor-based devices, we substituted the hydrogen resist with chlorine.

Hypothalamic demyelination causing panhypopituitarism.

Hypothalamic involvement in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is rare and endocrinopathies involving the hypothalamic-pituitary axis in patients with demyelinating conditions have rarely been reported. We present two cases of MS/NMOSD with associated hypothalamic-pituitary involvement and subsequent hypopituitarism, including the first report of a patient with hypothalamic demyelination causing panhypopituitarism. Differential diagnoses, including alemtuzumab-related and primary pituitary pathology are discussed.

Sr adatoms on As bridge positions on SrFe2As2 observed by scanning tunneling microscopy at 4.2 K.

We used a scanning tunneling microscope to image the surface of SrFe(2)As(2) single crystals at 4.2 K. We found, besides the commonly reported row structures and some disordered areas, also maze-like regions.

Phenolic analogs of the N,C-coupled naphthylisoquinoline alkaloid ancistrocladinium A, from Ancistrocladus cochinchinensis (Ancistrocladaceae), with improved antiprotozoal activities.

The first N,8'-coupled naphthylisoquinoline alkaloids with free phenolic OH groups, 4'-O-demethylancistrocladinium A and 6,4'-O-didemethylancistrocladinium A, have been isolated from the leaves and bark of the Vietnamese liana Ancistrocladus cochinchinensis, along with its known, non-phenolic parent compound, ancistrocladinium A, and four C,C-coupled representatives. The structure elucidation was achieved by chemical, spectroscopic, and chiroptical methods. The mono-phenolic alkaloid showed excellent activities in particular against the pathogen causing Chagas' disease, Trypanosoma cruzi.

A low temperature scanning tunneling microscopy system for measuring Si at 4.2 K.

In this paper we describe our low temperature scanning tunneling microscopy system with ultrahigh vacuum sample preparation capabilities. The main focus lies on the specialized silicon preparation facility which is the most unusual part. Other special solutions such as sample transport will also be described in detail.

Optic nerve head drusen and idiopathic intracranial hypertension in a 14-year-old girl.

A 14-year-old girl had a 3-month history of headache and blurred vision. Funduscopy showed bilateral optic disc edema. Findings on brain imaging were normal, and a diagnosis of idiopathic intracranial hypertension was confirmed after lumbar puncture showed an elevated opening pressure of 32 cm H(2)O.

A scanning tunneling microscopy study of a new superstructure around defects created by tip-sample interaction on 2H- NbSe(2).

A low temperature scanning tunneling microscope (LT-STM) was used to investigate a new superstructure on the cleaved surface of a 2H- NbSe(2) single crystal after introduction of structural defects through bias voltage pulses during tunneling at 4.2 K. A charge density wave (CDW) with a [Formula: see text] reconstruction was observed in the vicinity of the defects and the well-known 3 × 3 CDW was observed far from these defects.

Six naphthylisoquinoline alkaloids and a related benzopyranone from a Congolese Ancistrocladus species related to Ancistrocladus congolensis.

From the roots of a recently discovered Ancistrocladus taxon, with close affinities to Ancistrocladus congolensis regarding molecular ITS sequence data, six naphthylisoquinoline alkaloids, 5'-O-demethylhamatine (2), 5'-O-demethylhamatinine (3), 6-O-demethylancistroealaine A (4), 6,5'-O,O-didemethylancistroealaine A (5), 5-epi-6-O-methylancistrobertsonine A (6), and 5-epi-4'-O-demethylancistrobertsonine C (7), have been isolated, along with a likewise benzopyranone carboxylic acid, 8. The structural elucidation succeeded by chemical, spectroscopic, and chiroptical methods. Their bioactivities were tested against protozoan parasites causing severe tropical diseases.

Myotonic dystrophy type 1 presenting with ventilatory failure.

Objective: To report a series of patients with adult onset myotonic dystrophy type 1 (DM1) in whom the presenting symptom was ventilatory failure.

Background: Ventilatory failure is a common complication of DM1 and may be a presenting symptom in the setting of anesthesia or surgery, but it is not known to be a heralding manifestation.

Method: Case series.

Polyketide folding in higher plants: biosynthesis of the phenylanthraquinone knipholone.

The biosynthesis of knipholone, as an axially chiral phenylanthraquinone, in higher plants was examined by feeding experiments with [13C2]-labeled precursors. [13C2]-Acetate and advanced synthetic intermediates were fed to sterile cultures of Kniphofia pumila (Asphodelaceae), with subsequent NMR analysis on the isolated natural product involving 2D INADEQUATE and SELINQUATE experiments. Due to its uneven number of carbon atoms, and because of its uncertain decarboxylation site, the "northern" part of the molecule (i.

Flow rate limitation in open capillary channel flows.

This paper reports the experimental and theoretical investigations of forced liquid flows through open capillary channels under reduced gravity conditions. An open capillary channel is a structure that establishes a liquid flow path at low Bond numbers, when the capillary pressure caused by the surface tension force dominates in comparison to the hydrostatic pressure induced by gravitational or residual accelerations. In case of steady flow through the channel, the capillary pressure of the free surface balances the pressure difference between the liquid and the surrounding constant-pressure gas phase.

Axisymmetric surface oscillations in a cylindrical container with compensated gravity.

In this study the first mode of axisymmetric surface oscillations of a free liquid interface in a partly filled right circular cylinder under compensated gravity is investigated numerically. The situation is similar to a spacecraft that enters a ballistic flight at the end of thrust. A reorientation of the liquid of the free liquid surface toward the new equilibrium position takes place.

Different polyketide folding modes converge to an identical molecular architecture.

Metabolic diversity is being studied intensively by evolutionary biologists, but so far there has been no comparison of biosynthetic pathways leading to a particular secondary metabolite in both prokaryotes and eukaryotes. We have detected the bioactive anthraquinone chrysophanol, which serves as a chemical defense in diverse eukaryotic organisms, in a bacterial Nocardia strain, thereby permitting the first comparative biosynthetic study. Two basic modes of folding a polyketide chain to fused-ring aromatic structures have so far been described: mode F (referring to fungi) and mode S (from Streptomyces).

Surface composition of myrmecophilic plants: cuticular wax and glandular trichomes on leaves of Macaranga tanarius.

Primary plant surfaces, covered with cuticles consisting of cutin and waxes, are important substrates for interaction with insects. The composition of leaf surfaces of the myrmecophilic plant Macaranga tanarius was studied. The prenylated flavanone nymphaeol-C was identified in surface extracts and was localized exclusively in glandular trichomes on the abaxial leaf side.