Patient-specific implants made of 3D printed bioresorbable polymers at the point-of-care: material, technology, and scope of surgical application

BACKGROUND

Bioresorbable patient-specific additive-manufactured bone grafts, meshes, and plates are emerging as a promising alternative that can overcome the challenges associated with conventional off-the-shelf implants. The fabrication of patient-specific implants (PSIs) directly at the point-of-care (POC), such as hospitals, clinics, and surgical centers, allows for more flexible, faster, and more efficient processes, reducing the need for outsourcing to external manufacturers. We want to emphasize the potential advantages of producing bioresorbable polymer implants for cranio-maxillofacial surgery at the POC by highlighting its surgical applications, benefits, and limitations.

METHODS

This study describes the workflow of designing and fabricating degradable polymeric PSIs using three-dimensional (3D) printing technology. The cortical bone was segmented from the patient's computed tomography data using Materialise Mimics software, and the PSIs were designed created using Geomagic Freeform and nTopology software. The implants were finally printed via Arburg Plastic Freeforming (APF) of medical-grade poly (L-lactide-co-D, L-lactide) with 30% β-tricalcium phosphate and evaluated for fit.

RESULTS

3D printed implants using APF technology showed surfaces with highly uniform and well-connected droplets with minimal gap formation between the printed paths. For the plates and meshes, a wall thickness down to 0.8 mm could be achieved. In this study, we successfully printed plates for osteosynthesis, implants for orbital floor fractures, meshes for alveolar bone regeneration, and bone scaffolds with interconnected channels.

CONCLUSIONS

This study shows the feasibility of using 3D printing to create degradable polymeric PSIs seamlessly integrated into virtual surgical planning workflows. Implementing POC 3D printing of biodegradable PSI can potentially improve therapeutic outcomes, but regulatory compliance must be addressed.

Zero-Quantum-Defect Method and the Fundamental Vibrational Interval of H_{2}^{+}

The fundamental vibrational interval of H_{2}^{+} has been determined to be ΔG_{1/2}=2191.126 614(17)  cm^{-1} by continuous-wave laser spectroscopy of Stark manifolds of Rydberg states of H_{2} with the H_{2}^{+} ion core in the ground and first vibrationally excited states. Extrapolation of the Stark shifts to zero field yields the zero-quantum-defect positions -R_{H_{2}}/n^{2}, from which ionization energies can be determined. Our new result represents a 4-order-of-magnitude improvement compared to earlier measurements. It agrees, within the experimental uncertainty, with the value of 2191.126 626 344(17)(100)  cm^{-1} determined in nonrelativistic quantum electrodynamic calculations [V. Korobov, L. Hilico and J.-Ph. Karr, Phys. Rev. Lett. 118, 233001 (2017)PRLTAO0031-900710.1103/PhysRevLett.118.233001].

Comparison of Artificial Intelligence-Based Applications for Mandible Segmentation: From Established Platforms to In-House-Developed Software

Medical image segmentation, whether semi-automatically or manually, is labor-intensive, subjective, and needs specialized personnel. The fully automated segmentation process recently gained importance due to its better design and understanding of CNNs. Considering this, we decided to develop our in-house segmentation software and compare it to the systems of established companies, an inexperienced user, and an expert as ground truth. The companies included in the study have a cloud-based option that performs accurately in clinical routine (dice similarity coefficient of 0.912 to 0.949) with an average segmentation time ranging from 3'54″ to 85'54″. Our in-house model achieved an accuracy of 94.24% compared to the best-performing software and had the shortest mean segmentation time of 2'03″. During the study, developing in-house segmentation software gave us a glimpse into the strenuous work that companies face when offering clinically relevant solutions. All the problems encountered were discussed with the companies and solved, so both parties benefited from this experience. In doing so, we demonstrated that fully automated segmentation needs further research and collaboration between academics and the private sector to achieve full acceptance in clinical routines.

CNN-Based Identification of Parkinson's Disease from Continuous Speech in Noisy Environments

Parkinson's disease is a progressive neurodegenerative disorder caused by dopaminergic neuron degeneration. Parkinsonian speech impairment is one of the earliest presentations of the disease and, along with tremor, is suitable for pre-diagnosis. It is defined by hypokinetic dysarthria and accounts for respiratory, phonatory, articulatory, and prosodic manifestations. The topic of this article targets artificial-intelligence-based identification of Parkinson's disease from continuous speech recorded in a noisy environment. The novelty of this work is twofold. First, the proposed assessment workflow performed speech analysis on samples of continuous speech. Second, we analyzed and quantified Wiener filter applicability for speech denoising in the context of Parkinsonian speech identification. We argue that the Parkinsonian features of loudness, intonation, phonation, prosody, and articulation are contained in the speech, speech energy, and Mel spectrograms. Thus, the proposed workflow follows a feature-based speech assessment to determine the feature variation ranges, followed by speech classification using convolutional neural networks. We report the best classification accuracies of 96% on speech energy, 93% on speech, and 92% on Mel spectrograms. We conclude that the Wiener filter improves both feature-based analysis and convolutional-neural-network-based classification performances.

Shape Resonances in H_{2} as Photolysis Reaction Intermediates

Shape resonances in H_{2}, produced as reaction intermediates in the photolysis of H_{2}S precursor molecules, are measured in a half-collision approach. Before disintegrating into two ground state H atoms, the reaction is quenched by two-photon Doppler-free excitation to the F electronically excited state of H_{2}. For J=13, 15, 17, 19, and 21, resonances with lifetimes in the range of nano- to milliseconds were observed with an accuracy of 30 MHz (1.4 mK). The experimental resonance positions are found to be in excellent agreement with theoretical predictions when nonadiabatic and quantum electrodynamical corrections are included. This is the first time such effects are observed in collisions between neutral atoms. From the potential energy curve of the H_{2} molecule, now tested at high accuracy over a wide range of internuclear separations, the s-wave scattering length for singlet H(1s)+H(1s) scattering is determined at a=0.2735_{31}^{39} a_{0}.

Photolysis Production and Spectroscopic Investigation of the Highest Vibrational States in H2 (X1Σg+ v = 13, 14)

Rovibrational quantum states in the X1Σg+ electronic ground state of H2 are prepared in the v = 13 vibrational level up to its highest bound rotational level J = 7, and in the highest bound vibrational level v = 14 (for J = 1) by two-photon photolysis of H2S. These states are laser-excited in a subsequent two-photon scheme into F1Σg+ outer well states, where the assignment of the highest (v,J) states is derived from a comparison of experimentally known levels in F1Σg+, combined with ab initio calculations of X1Σg+ levels. The assignments are further verified by excitation of F1Σg+ population into autoionizing continuum resonances, which are compared with multichannel quantum defect calculations. Precision spectroscopic measurements of the F-X intervals form a test for the ab initio calculations of ground state levels at high vibrational quantum numbers and large internuclear separations, for which agreement is found.

Bite force and its relationship to jaw shape in domestic dogs

Previous studies based on two-dimensional methods have suggested that the great morphological variability of cranial shape in domestic dogs has impacted bite performance. Here, we used a three-dimensional biomechanical model based on dissection data to estimate the bite force of 47 dogs of various breeds at several bite points and gape angles. In vivo bite force for three Belgian shepherd dogs was used to validate our model. We then used three-dimensional geometric morphometrics to investigate the drivers of bite force variation and to describe the relationships between the overall shape of the jaws and bite force. The model output shows that bite force is rather variable in dogs and that dogs bite harder on the molar teeth and at lower gape angles. Half of the bite force is determined by the temporal muscle. Bite force also increased with size, and brachycephalic dogs showed higher bite forces for their size than mesocephalic dogs. We obtained significant covariation between the shape of the upper or lower jaw and absolute or residual bite force. Our results demonstrate that domestication has not resulted in a disruption of the functional links in the jaw system in dogs and that mandible shape is a good predictor of bite force.

Determination of the Interval between the Ground States of Para- and Ortho-H_{2}

Nuclear-spin-symmetry conservation makes the observation of transitions between quantum states of ortho- and para-H_{2} extremely challenging. Consequently, the energy-level structure of H_{2} derived from experiment consists of two disjoint sets of level energies, one for para-H_{2} and the other for ortho-H_{2}. We use a new measurement of the ionization energy of para-H_{2} [E_{I}(H_{2})/(hc)=124 417.491 098(31)  cm^{-1}] to determine the energy separation [118.486 770(50)  cm^{-1}] between the ground states of para- and ortho-H_{2} and thus link the energy-level structure of the two nuclear-spin isomers of this fundamental molecule. Comparison with recent theoretical results [M. Puchalski et al., Phys. Rev. Lett. 122, 103003 (2019)PRLTAO0031-900710.1103/PhysRevLett.122.103003] enables the derivation of an upper bound of 1.5 MHz for a hypothetical global shift of the energy-level structure of ortho-H_{2} with respect to that of para-H_{2}.

A hydrochemically guided landscape classification system for modelling spatial variation in multiple water quality indices: Process-attribute mapping

Spatial variation in landscape attributes can account for much of the variability in water quality relative to land use on its own. Such variation results from the coupling between the dominant processes governing water quality, namely hydrological, redox, and weathering and gradients in key landscape attributes, such as topography, geology, and soil drainage. Despite the importance of 'process-attribute' gradients (PAG), few water quality models explicitly account for their influence. Here a processes-based water quality modelling framework is presented that more completely accounts for the role of landscape variability over water quality - Process-Attribute Mapping (PoAM). Critically, hydrochemical measures form the basis for the identification and mapping of effective landscape attributes, producing PAG maps that attempt to replicate the natural landscape gradients governing each dominant process. Application to the province of Southland (31,824 km²), New Zealand, utilised 12 existing geospatial datasets and a total of 28,626 surface water, groundwater, spring, soil water, and precipitation analyses to guide the identification and mapping of 11 individual PAG. The ability of PAGs to replicate regional hydrological, redox, and weathering gradients was assessed on the accuracy with which the hydrochemical indicators of each dominant process (e.g. hydrological tracers, redox indicators) were estimated across 93 long-term surface water monitoring sites (cross-validated R² values of 0.75-0.95). Given hydrochemical evidence that PAGs replicate actual landscape gradients governing the dominant processes, they were combined with a land use intensity layer and used to estimate steady-state surface water quality. Cross-validated R² values ranged between 0.81 and 0.92 for median total nitrogen, total oxidised nitrogen, total phosphorus and dissolved reactive phosphorus. Models of particulate species E. coli and total suspended sediment, although reasonable (R² 0.72-0.73), were less accurate, suggesting finer-grained land use, landscape attribute, and/or flow normalised measures are required to improve estimation.

Dissociation Energy of the Hydrogen Molecule at 10^{-9} Accuracy

The ionization energy of ortho-H_{2} has been determined to be E_{I}^{o}(H_{2})/(hc)=124 357.238 062(25)  cm^{-1} from measurements of the GK(1,1)-X(0,1) interval by Doppler-free, two-photon spectroscopy using a narrow band 179-nm laser source and the ionization energy of the GK(1,1) state by continuous-wave, near-infrared laser spectroscopy. E_{I}^{o}(H_{2}) was used to derive the dissociation energy of H_{2}, D_{0}^{N=1}(H_{2}), at 35 999.582 894(25)  cm^{-1} with a precision that is more than one order of magnitude better than all previous results. The new result challenges calculations of this quantity and represents a benchmark value for future relativistic and QED calculations of molecular energies.

Mineral mediated isotope fractionation of soil water

RATIONALE

The ability to recover the isotopic signature of water added to soil samples that have previously been oven-dried decreases with the increasing presence of silt and clay. The effects on the isotopic signature of water associated with physicochemical soil properties are not yet fully understood, for either hydration or dehydration of soil samples.

METHODS

The soil sample chemistry and the crystallinity of minerals were measured by X-ray fluorescence and X-ray diffraction. The organic carbon and the cation-exchange capacity were also determined. Water of known isotopic signature was used to spike an oven-dried substrate and subsequently extracted by cryogenic vacuum extraction at a temperature of 105°C. In addition, the soils were oven-dried at 205°C and water extractions were also performed at 205°C. The isotopic signatures of the water samples were determined by cavity-ring-down spectrometry.

RESULTS

The isotope effects caused by the cryogenic vacuum extraction method applied to soils with elevated clay content were reduced. First, by increasing the extraction temperature to 205°C, we improved the precision of the cryogenic vacuum extraction method and the recovery of the known isotopic signature of the spike water. Secondly, the post-correction of data based on the physicochemical soil properties and a common extraction temperature of 105°C improved the measurement trueness.

CONCLUSIONS

The isotopic signature of soil water is influenced by mineral-water interaction. During the hydration of clay, different minerals deplete free water in heavy isotopes. The extracted soil water (dehydration water) gathered from clay-rich soils is generally more depleted in the heavy isotopes than the spike water, making results obtained for different soil types difficult to compare. Isotope effects observed at the mineral-water interface highlight potential explanations for eco-hydrological separation of water pools. Copyright © 2016 John Wiley & Sons, Ltd.

[How Patients View and Accept Health Care Services Provided by Health Care Assistants in the General Practice: Survey of Participants of the GP-centered Health Care Program in Baden-Wuerttemberg]

BACKGROUND

In recent years, models for the delegation of GP tasks to non-physician medical staff have been tested, implemented in a general practice setting and, to some extent, funded by health insurance companies.

AIM

How were changes in the spectrum of tasks performed by non-physician staff viewed and accepted by patients?

METHODS

Between October 2014 and January 2015, a written survey was conducted among chronically ill patients (≥ 65 years of age) receiving health care from health care assistants (HCA) with or without the additional "health care assistant in the family practice", or VERAH qualification. Using a self-developed survey, based on a previous collection of data, patients were asked about various aspects of health care provided by HCAs.

RESULTS

77 practices participated and a total of 1 266 patients were surveyed. The patients said the HCAs had a role to play in many aspects of their health care. More than half the patients said HCAs could take responsibility for some of the home visits and contacts in the practice. Almost without exception, patients regarded the organisational, healthcare and other supporting services performed by the HCAs as very good. The results were more heterogeneous for specific consulting services. While consultations on vaccinations, preventive services, medical examinations and medication adherence were well accepted, this was much less often the case with advice on lifestyle. Many patients see HCAs as additional and competent persons they can trust, and could well imagine HCAs taking on responsibility for further delegable services.

CONCLUSION

At least among GP-centered health care programme participants, many healthcare services delegated to HCAs were appreciated and accepted by patients. Home visits and case management, in the sense of structured individual health care for patients with special needs, are further services that may be well suited for delegation. This should be investigated in further studies (including qualitative studies).

[Cutaneous Rosai-Dorfman syndrome. Successful therapy with intrralesional corticosteroids]

BACKGROUND

Cutaneous Rosai-Dorfman disease is a rare disorder belonging to the spectrum of non-Langerhans cell histiocytoses. It is characterized by dermal and subcutaneous infiltrates of histiocytes as well as accompanying lymphocytes, plasma cells and granulocytes. Because it is so rare, standard therapies have not been established.

CASE REPORT

A 27-year-old man showed an excellent response to intralesional corticosteroids after unsuccessful prior treatment with methotrexate, systemic steroids and surgery as well as laser therapy.

Precision measurements of ionization and dissociation energies by extrapolation of Rydberg series: from H2 to larger molecules

Recent experiments are reviewed which have led to the determination of the ionization and dissociation energies of molecular hydrogen with a precision of 0.0007 cm(-)1 (8 mJ/mol or 20 MHz) using a procedure based on high-resolution spectroscopic measurements of high Rydberg states and the extrapolation of the Rydberg series to the ionization thresholds. Molecular hydrogen, with only two protons and two electrons, is the simplest molecule with which all aspects of a chemical bond, including electron correlation effects, can be studied. Highly precise values of its ionization and dissociation energies provide stringent tests of the precision of molecular quantum mechanics and of quantum-electrodynamics calculations in molecules. The comparison of experimental and theoretical values for these quantities enable one to quantify the contributions to a chemical bond that are neglected when making the Born-Oppenheimer approximation, i.e. adiabatic, nonadiabatic, relativistic, and radiative corrections. Ionization energies of a broad range of molecules can now be determined experimentally with high accuracy (i.e. about 0.01 cm(-1)). Calculations at similar accuracies are extremely challenging for systems containing more than two electrons. The combination of precision measurements of molecular ionization energies with highly accurateab initio calculations has the potential to provide, in future, fully reliable sets of thermochemical quantities for gas-phase reactions.

High-resolution two-phase flow measurement techniques for the generation of experimental data for CFD code qualification

Computational fluid dynamics simulations for two-phase flows are important in different fields of engineering and science. Since two-phase flows are inherently complex, also CFD modeling development requires special attention. The validation of model implementation and the derivation of physics based models for momentum, heat, and mass transfer in two-phase flow require experiments with generation of high-resolution measurement data. This, however, is a great challenge, since most standard flow measurement tools used in single phase flow situations, are not suited for multiphase flows. In this article we report on advanced imaging and measuring methods for two-phase flow experiments, which have been extensively used in the recent past to conduct experiments for two-phase flows at the Helmholtz-Zentrum Dresden-Rossendorf. In particular the application of wire-mesh sensors, ultrafast X-ray tomography, gamma ray tomography and positron emission tomography will be introduced and discussed.

Phytotoxicity of zinc and manganese to seedlings grown in soil contaminated by zinc smelting

Historic emissions from two zinc smelters have injured the forest on Blue Mountain near Palmerton, Pennsylvania, USA. Seedlings of soybeans and five tree species were grown in a greenhouse in a series of mixtures of smelter-contaminated and reference soils and then phytotoxic thresholds were calculated. As little as 10% Palmerton soil mixed with reference soil killed or greatly stunted seedlings of most species. Zinc was the principal cause of the phytotoxicity to the tree seedlings, although Mn and Cd may also have been phytotoxic in the most contaminated soil mixtures. Calcium deficiency seemed to play a role in the observed phytotoxicity. Exposed soybeans showed symptoms of Mn toxicity. A test of the effect of liming on remediation of the Zn and Mn phytotoxicity caused a striking decrease in Sr-nitrate extractable metals in soils and demonstrated that liming was critical to remediation and restoration.

The multipurpose thermalhydraulic test facility TOPFLOW: an overview on experimental capabilities, instrumentation and results

A new multipurpose thermalhydraulic test facility TOPFLOW (TwO Phase FLOW) was built and put into operation at Forschungszentrum Rossendorf in 2002 and 2003. Since then, it has been mainly used for the investigation of generic and applied steady state and transient two phase flow phenomena and the development and validation of models of Computational Fluid Dynamic (CFD) codes in the frame of the German CFD initiative. The advantage of TOPFLOW consists in the combination of a large scale of the test channels with a wide operational range both of the flow velocities as well as of the system pressures and temperatures plus finally the availability of a special instrumentation that is capable in high spatial and temporal resolving two phase flow phenomena, for example the wire-mesh sensors.

Survivin in adrenocortical tumors - pathophysiological implications and therapeutic potential

Treatment options for adrenocortical carcinoma (ACC) are very limited. In other solid tumors, small vaccination trials targeting the anti-apoptotic molecule survivin suggested immunological and clinical benefit in selected patients. Therefore, we investigated whether survivin might be a suitable target for immunotherapy in ACC. Survivin mRNA and protein expression was assessed in adrenal tissue specimens [by real-time-PCR in 29 ACC, 24 adrenocortical adenomas (ACA) and 12 normal adrenal glands; by immunohistochemistry in 167 ACCs, 15 ACA, and 5 normal adrenal glands]. Expression was correlated with clinical outcome using Kaplan-Meier and Cox regression analyses. The anti-apoptotic role of survivin was investigated in the SW13 ACC cell line using survivin siRNA. The presence of spontaneous survivin specific T-cells in peripheral blood was assessed by FACS dextramere staining in 29 ACC patients in comparison to healthy controls. Survivin mRNA in ACC was significantly overexpressed when compared with ACA or normal adrenal glands. Immunohistochemistry confirmed survivin protein expression in 97% of the ACCs. In 83% of samples, staining was moderate or high and clinical outcome in this subgroup showed a trend towards poorer prognosis [hazard ratio for death 2.28 (95% CI 0.99-5.28); p=0.053]. Survivin knockdown in SW-13 cell significantly increased the rate of apoptosis. Finally, spontaneous survivin-reactive T cells were detectable in 3 of 29 ACC patients. In conclusion, our data suggest that survivin could play an important role in the anti-apoptotic mechanisms in ACC and provide first hints that targeting survivin might be an interesting new therapeutic approach in this rare disease.