Stable and accurate atomistic simulations of flexible molecules using conformationally generalisable machine learned potentials.

Computational simulation methods based on machine learned potentials (MLPs) promise to revolutionise shape prediction of flexible molecules in solution, but their widespread adoption has been limited by the way in which training data is generated. Here, we present an approach which allows the key conformational degrees of freedom to be properly represented in reference molecular datasets. MLPs trained on these datasets using a global descriptor scheme are generalisable in conformational space, providing quantum chemical accuracy for all conformers.

Accuracy of correction of a hexapod frame, patient-specific osteotomy and reduction guides, and hinged circular external fixation in a 3D-printed canine antebrachial deformity model.

Objectives: This study aimed to objectively define whether human hexapod fixation (Maxframe), with or without the use of 3D-printed positioning guides, can correct a canine antebrachial deformity with greater accuracy than the clinically established techniques of 3D patient-specific osteotomy and reduction guides (3D-PSORG) or hinged circular external skeletal fixation (CESF).

Methods: CT of a canine antebrachium was manipulated to induce distal radial deformity of the valgus, external torsion, and procurvatum, each of magnitude 20. Five experiments were performed to correct the deformity via a distal radial and ulna opening osteotomy using: (1) A 3D-PSORG with the application of a locking plate, (2) hinged CESF, (3) Maxframe standard protocol, (4) Maxframe applied with patient-specific positioning guides (PSPGs), and (5) Maxframe with frame adjustment calculated from post-application CT.

A neural network potential based on pairwise resolved atomic forces and energies.

Molecular simulations have become a key tool in molecular and materials design. Machine learning (ML)-based potential energy functions offer the prospect of simulating complex molecular systems efficiently at quantum chemical accuracy. In previous work, we have introduced the ML-based PairF-Net approach to neural network potentials, that adopts a pairwise interatomic scheme to predicting forces within a molecular system.

A ring of rotaxanes: studies of a large paramagnetic assembly in solution.

Here we report the synthesis and structural characterization of four [7]rotaxanes formed by coordinating hybrid inorganic-organic [2]rotaxanes to a central {Ni} core. X-ray single crystal diffraction demonstrate that [7]rotaxanes are formed, with a range of conformations in the crystal. Small angle X-ray scattering supported by molecular dynamic simulations demonstrates that the large molecules are stable in solution and also show that the conformers present in solution are not those found in the crystal.

Review of minimally invasive surgical procedures for assessment and treatment of medial coronoid process disease.

Objective: To summarize the current peer-reviewed publications on minimally invasive surgery (MIS) for medial coronoid process disease (MCPD) in dogs.

Study Design: Invited review.

Methods: Pubmed, CAB Abstracts and Scopus databases were utilized for literature review (1990-2023).

Evaluation of cervical lymph nodes using multispectral optoacoustic tomography: a proof-of-concept study.

Objectives: Examination of lymph nodes is one of the most common indications for imaging in the head and neck region. The purpose of this study is to evaluate whether multispectral optoacoustic tomography can be used to observe chromophore differences between benign and malignant neck lymph nodes.

Materials And Methods: Proof-of-concept ex vivo study of resected cervical lymph nodes from 11 patients.

Adduct Ions as Diagnostic Probes of Metallosupramolecular Complexes Using Ion Mobility Mass Spectrometry.

Following electrospray ionization, it is common for analytes to enter the gas phase accompanied by a charge-carrying ion, and in most cases, this addition is required to enable detection in the mass spectrometer. These small charge carriers may not be influential in solution but can markedly tune the analyte properties in the gas phase. Therefore, measuring their relative influence on the target molecule can assist our understanding of the structure and stability of the analyte.

Disassembly Mechanisms and Energetics of Polymetallic Rings and Rotaxanes.

Understanding the fundamental reactivity of polymetallic complexes is challenging due to the complexity of their structures with many possible bond breaking and forming processes. Here, we apply ion mobility mass spectrometry coupled with density functional theory to investigate the disassembly mechanisms and energetics of a family of heterometallic rings and rotaxanes with the general formula [NHRR'][CrMF(OCBu)] with M = Mn, Fe, Co, Ni, Cu, Zn, Cd. Our results show that their stability can be tuned both by altering the d-metal composition in the macrocycle and by the end groups of the secondary ammonium cation [NHRR'].

Efficacy of Co-Trimoxazole against Experimental Melioidosis Acquired by Different Routes of Infection.

Burkholderia pseudomallei is the causative agent of melioidosis and presents with diverse clinical manifestations. Naturally occurring infection occurs following contamination of cuts or skin abrasions, or ingestion of contaminated water, and occasionally through inhalational of infected soil or water particles. The influence of the route of disease acquisition on the efficacy of medical countermeasures has not been explored in humans or in appropriate animal models.

Disproportionation of the Uranyl(V) Coordination Complexes in Aqueous Solution through Outer-Sphere Electron Transfer.

Among the linear actinyl(VI/V) cations, the uranyl(V) species are particularly intriguing because they are unstable and exhibit a unique behavior to undergo H promoted disproportionation in aqueous solution and form stable uranyl(VI) and U(IV) complexes. This study uses density functional theory (DFT) combined with the conductor-like polarizable continuum model approach to investigate [UO] to [UO] reduction free energies (RFEs) and explores the stability of uranyl(V) complexes in aqueous solution through computing disproportionation free energies (DFEs) for an outer-sphere electron transfer process. In addition to the aqua complex (U1), another three commonly encountered ligands such as chloride (U2), acetate (U3), and carbonate (U4) in aqueous environmental conditions are taken into account.

Clients' perception of referral and veterinary specialists in a U.K. small animal referral hospital.

Background: A 2011 RCVS report published following review of veterinary referral and specialisation suggested that the general public may have a lack of understanding of what constitutes specialisation. Our questionnaire study evaluated client understanding of the term 'Specialist' and the information obtained prior to referral.

Methods: Questionnaires were completed prior to consultation.

Gold(i) bridged dimeric and trimeric heterometallic {CrNi}-based qubit systems and their characterization.

Gold(i) bridged dimeric and trimeric structures of a ground state spin S = 1/2 heterometallic {CrNi} wheel have been prepared and studied by continuous wave (CW) and pulsed wave EPR spectrometry. The {CrNi} relaxation time constants (T and T) show rates matching well with previous observations. Four pulse Double Electron Resonance (DEER) studies suggest presence of more than one conformations.

The potential of microdialysis to estimate rifampicin concentrations in the lung of guinea pigs.

Optimised pre-clinical models are required for TB drug development to better predict the pharmacokinetics of anti-tuberculosis (anti-TB) drugs to shorten the time taken for novel drugs and combinations to be approved for clinical trial. Microdialysis can be used to measure unbound drug concentrations in awake freely moving animals in order to describe the pharmacokinetics of drugs in the organs as a continuous sampling technique. The aim of this work was to develop and optimise the microdialysis methodology in guinea pigs to better understand the pharmacokinetics of rifampicin in the lung.

Isolated Articular Fractures of the Canine Talus: Diagnosis and Signalment in Fourteen Dogs.

Objective:  The aim of this retrospective multicentre case series was to describe signalment, presenting signs and imaging findings in dogs with isolated articular fractures of the talus.

Study Design:  Medical records (2008-2019) of dogs with isolated articular talar fractures were reviewed.

Results:  Fourteen dogs met the inclusion criteria; affected breeds were four German Pointer (three shorthair and one wirehaired), three Labrador Retrievers, two Rottweilers, two Springer Spaniels, one cross breed, one Greyhound and one Great Münsterländer.

Outcome following surgical stabilization of distal diaphyseal and supracondylar femoral fractures in dogs.

Signalment, clinical features, fixation techniques, complications, and outcome for dogs presenting with distal diaphyseal and supracondylar femoral fractures were retrospectively reviewed. A total of 45 dogs with unilateral femoral fractures were included. Supracondylar femoral plates were the most popular method of fixation.

Conformational Flexibility of Hybrid [3]- and [4]-Rotaxanes.

The synthesis, structures, and properties of [4]- and [3]-rotaxane complexes are reported where [2]-rotaxanes, formed from heterometallic {CrNi} rings, are bound to a fluoride-centered {CrNi} triangle. The compounds have been characterized by single-crystal X-ray diffraction and have the formulas [CrNi(F)(OCBu)]{(H)[CrNiF(OCBu)]} () and [CrNi(F)(OCBu)(THF)]{(H)[CrNiF(OCBu)]} (), where = py-CHCHNHCHCHSCH. The [4]-rotaxane is an isosceles triangle of three [2]-rotaxanes bound to the central triangle while the [3]-rotaxane contains only two [2]-rotaxanes bound to the central triangle.

Three-Dimensional-Printed Patient-Specific Osteotomy Guides, Repositioning Guides and Titanium Plates for Acute Correction of Antebrachial Limb Deformities in Dogs.

Objective:  The aim of this study was to describe the use of patient-specific three-dimensional (3D)-printed osteotomy guides, repositioning guides and custom-printed titanium plates for acute correction of antebrachial limb deformities in four dogs.

Methods:  Retrospective review of antebrachial limb deformities in small breed chondrodystrophic dogs that were surgically corrected using a closing wedge ostectomy of the radius at a predetermined site using patient-specific osteotomy guides. Reduction was achieved without the need for intraoperative measurements using patient-specific 3D-printed repositioning guides secured and manipulated using temporary Kirschner wire fixation.

A [13]rotaxane assembled via a palladium molecular capsule.

Molecules that are the size of small proteins are difficult to make. The most frequently examined route is via self-assembly, and one particular approach involves molecular nanocapsules, where ligands are designed that will enforce the formation of specific polyhedra of metals within the core of the structure. Here we show that this approach can be combined with mechanically interlocking molecules to produce nanocapsules that are decorated on their exterior.

Uranyl-Bound Tetra-Dentate Non-Innocent Ligands: Prediction of Structure and Redox Behaviour Using Density Functional Theory.

Computational methods have been applied to understand the reduction potentials of [UO -salmnt-L] complexes (L=pyridine, DMSO, DMF and TPPO), and their redox behavior is compared with previous experiments in dichloromethane solution. Since the experimental results were inconclusive regarding the influence of the uranyl-bound tetra-dentate 'salmnt' ligand, here we will show that salmnt acts as a redox-active ligand and exhibits non-innocent behavior to interfere with the otherwise expected one-electron metal (U) reduction. We have employed two approaches to determine the uranyl (VI/V) reduction potentials, using a direct study of one-electron reduction processes and an estimation of the overall reduction using isodesmic reactions.

Lateral Radial Head Subluxation as a Complication Following Proximal Ulnar Osteotomy or Ostectomy in Eight Dogs.

Objectives:  The aim of this study was to report the complication of lateral radial head subluxation following proximal ulnar osteotomy (PUOO) or proximal ulnar ostectomy (PUOE) in eight dogs.

Materials And Methods:  Case records and diagnostic imaging of dogs developing lateral radial head subluxation following PUOO ( = 7) or PUOE ( = 2) were retrospectively reviewed. Information pertaining to clinical history, signalment, presenting condition, lameness grade, diagnostic imaging and initial surgery details, postoperative complications and their management were retrieved.

Density functional theory (DFT) calculations of VI/V reduction potentials of uranyl coordination complexes in non-aqueous solutions.

Of particular interest within the +6 uranium complexes is the linear uranyl(vi) cation and it forms numerous coordination complexes in solution and exhibits incongruent redox behavior depending on coordinating ligands. In this study, to determine the reduction potentials of uranyl complexes in non-aqueous solutions, a hybrid density functional theory (DFT) approach was used in which two different DFT functionals, B3LYP and M06, were applied. Bulk solvent effects were invoked through the conductor-like polarizable continuum model.

Evaluation of the milling technique on the component-bone interface in the TATE elbow.

Objective: To determine whether the surgeon can influence the accuracy of milling during the TATE elbow arthroplasty by applying force to the milling arm during the milling procedure.

Study Design: In vitro study on Sawbone specimens.

Sample Population: Thirty identical solid foam models of the canine right humerus, elbow joint, and antebrachium (size large).

Radiological Evaluation of TATE Elbow Cartridge Position in Dogs.

Objective:  The main purpose of this study was to evaluate the effect of varying elbow flexion angle and elbow orientation on the radiological measurement of component position for first (1G) and second-generation (2G) TATE elbow cartridges, and to test intra/inter-observer variability of measurements.

Materials And Methods:  A cadaveric thoracic limb was implanted with a 1G then 2G cartridge, and mounted in lateral recumbency on an acrylic platform. The platform was tilted by set increments up to 10° in both planes, and radiographs were performed at each angle before repeating with the limb in caudocranial positioning.