bluuebunny/crossref_metadata_2025 huggingface dataset:
Supra-company apprenticeship training in Austria: a synopsis of empirical findings on a possibly early phase of a new pillar within VET
Authors: Schlögl Peter , Mayerl Martin , Löffler Roland , Schmölz Alexander
Published: November 2020

Since 2008, the Austrian Vocational Training Act has given young people the opportunity to obtain vocational qualifications in supra-company training workshops. In addition to the traditional full-time vocational school system and company-based apprenticeship training, a third vocational qualification path has thus been established. This article presents empirical findings on this innovation in skill formation and examines the question of whether conditions for the sustainable establishment of a third pillar for acquiring vocational qualifications are given with regard to regulatory, normative, and cultural cognitive dimensions.
Functional genomic analyses uncover APOE-mediated regulation of brain and cerebrospinal fluid beta-amyloid levels in Parkinson disease
Authors: Ibanez Laura , Bahena Jorge A. , Yang Chengran , Dube Umber , Farias Fabiana H. G. , Budde John P. , Bergmann Kristy , Brenner-Webster Carol , Morris John C. , Perrin Richard J. , Cairns Nigel J. , O’Donnell John , Álvarez Ignacio , Diez-Fairen Monica , Aguilar Miquel , Miller Rebecca , Davis Albert A. , Pastor Pau , Kotzbauer Paul , Campbell Meghan C. , Perlmutter Joel S. , Rhinn Herve , Harari Oscar , Cruchaga Carlos , Benitez Bruno A.
Published: November 2020

Alpha-synuclein is the main protein component of Lewy bodies, the pathological hallmark of Parkinson’s disease. However, genetic modifiers of cerebrospinal fluid (CSF) alpha-synuclein levels remain unknown. The use of CSF levels of amyloid beta1–42, total tau, and phosphorylated tau181 as quantitative traits in genetic studies have provided novel insights into Alzheimer’s disease pathophysiology. A systematic study of the genomic architecture of CSF biomarkers in Parkinson’s disease has not yet been conducted. Here, genome-wide association studies of CSF biomarker levels in a cohort of individuals with Parkinson’s disease and controls (N = 1960) were performed. PD cases exhibited significantly lower CSF biomarker levels compared to controls. A SNP, proxy for APOE ε4, was associated with CSF amyloid beta1–42 levels (effect = − 0.5, p = 9.2 × 10−19). No genome-wide loci associated with CSF alpha-synuclein, total tau, or phosphorylated tau181 levels were identified in PD cohorts. Polygenic risk score constructed using the latest Parkinson’s disease risk meta-analysis were associated with Parkinson’s disease status (p = 0.035) and the genomic architecture of CSF amyloid beta1–42 (R2 = 2.29%; p = 2.5 × 10−11). Individuals with higher polygenic risk scores for PD risk presented with lower CSF amyloid beta1–42 levels (p = 7.3 × 10−04). Two-sample Mendelian Randomization revealed that CSF amyloid beta1–42 plays a role in Parkinson’s disease (p = 1.4 × 10−05) and age at onset (p = 7.6 × 10−06), an effect mainly mediated by variants in the APOE locus. In a subset of PD samples, the APOE ε4 allele was associated with significantly lower levels of CSF amyloid beta1–42 (p = 3.8 × 10−06), higher mean cortical binding potentials (p = 5.8 × 10−08), and higher Braak amyloid beta score (p = 4.4 × 10−04). Together these results from high-throughput and hypothesis-free approaches converge on a genetic link between Parkinson’s disease, CSF amyloid beta1–42, and APOE.
Characteristics of secondary-ruptured faults in the Aso Caldera triggered by the 2016 Mw 7.0 Kumamoto earthquake
Authors: Fukushima Yo , Ishimura Daisuke
Published: November 2020

The 16 April 2016 Mw 7.0 Kumamoto earthquake caused prominent fault displacements and crustal deformation, not only around the main rupture faults but also around numerous secondary-ruptured faults. The physics and characteristics of such secondary faulting have not yet been studied in detail. We investigated a set of two secondary faults that appeared at the timing of the Mw 7.0 quake in the Aso Caldera by mainly using synthetic aperture radar interferometry and fault slip modeling. The two faults were found to be associated with surface displacement offsets of several centimeters or more, in the oblique sense of right-lateral and vertical motion. Fault slip inversions found that the slip was dominantly in normal sense with smaller contribution from the right-lateral component. The deeper limit of the slips was estimated to be around 1.3 km, which may coincide with the boundary between the superficial sediment layer and the basement rock. The shallowness of the slip and the difference in the dip angles of the main secondary fault and the Mw 7.0 seismogenic fault suggest separation of the two fault systems, although the fault strike and sense of motions were similar. The amount of slip on the two secondary faults was larger than that expected from the scaling law derived from seismogenic faults, which may indicate the difference in the physics of seismogenic and secondary faultings.
Understanding subjective well-being: perspectives from psychology and public health
Authors: Das Kirti V. , Jones-Harrell Carla , Fan Yingling , Ramaswami Anu , Orlove Ben , Botchwey Nisha
Published: November 2020

Background

Individual subjective well-being (SWB) is essential for creating and maintaining healthy, productive societies. The literature on SWB is vast and dispersed across multiple disciplines. However, few reviews have summarized the theoretical and empirical tenets of SWB literature across disciplinary boundaries.

Methods

We cataloged and consolidated SWB-related theories and empirical evidence from the fields of psychology and public health using a combination of online catalogs of scholarly articles and online search engines to retrieve relevant articles. For both theories and determinants/correlates of SWB, PubMed, PsychINFO, and Google Scholar were used to obtain relevant articles. Articles for the review were screened for relevance, varied perspectives, journal impact, geographic location of study, and topicality. A core theme of SWB empirical literature was the identification of SWB determinants/correlates, and over 100 research articles were reviewed and summarized for this review.

Results

We found that SWB theories can be classified into four groups: fulfillment and engagement theories, personal orientation theories, evaluative theories, and emotional theories. A critical analysis of the conflicts and overlaps between these theories reveals the lack of a coherent theoretical and methodological framework that would make empirical research systematically comparable. We found that determinants/correlates of SWB can be grouped into seven broad categories: basic demographics, socioeconomic status, health and functioning, personality, social support, religion and culture, and geography and infrastructure. However, these are rarely studied consistently or used to test theories.

Conclusions

The lack of a clear, unifying theoretical basis for categorizing and comparing empirical studies can potentially be overcome using an operationalizable criterion that focuses on the dimension of SWB studied, measure of SWB used, design of the study, study population, and types of determinants and correlates. From our review of the empirical literature on SWB, we found that the seven categories of determinants/correlates identified may potentially be used to improve the link between theory and empirical research, and that the overlap in the determinant/correlates as they relate to multiple theory categories may enable us to test theories in unison. However, doing so in the future would require a conscious effort by researchers in several areas, which are discussed.
Cell Banking of HEK293T cell line for clinical-grade lentiviral particles manufacturing
Authors: Perpiñá Unai , Herranz Cristina , Martín-Ibáñez Raquel , Boronat Anna , Chiappe Felipe , Monforte Verónica , Orpella-Aceret Gemma , González Ester , Olivé Myriam , Castella María , Suñé Guillermo , Urbano-Ispizua Álvaro , Delgado Julio , Juan Manel , Canals Josep M.
Published: November 2020

Background

Cell banks are widely used to preserve cell properties as well as to record and control the use of cell lines in biomedical research. The generation of cell banks for the manufacturing of Advanced Therapy Medicinal Products, such as cell and gene therapy products, must comply with current Good Manufacturing Practice regulations. The quality of the cell lines used as starting materials in viral-vector manufacturing processes must be also assessed.

Methods

Three batches of a Master Cell Bank and a Working Cell Bank of the HEK293T cell line were manufactured under current Good Manufacturing Practices regulations. Quality control tests were performed according to product specifications. Process validation includes the training of manufacturing personnel by performing simulation tests, and the continuous measurement of environmental parameters such as air particles and microorganisms. Cell number and viability of cryopreserved cells were periodically measured in order to define the stability of these cellular products.

Results

All batches of HEK293T Master and Working Cell Banks met the acceptance criteria of their specifications showing the robustness and homogeneity of the processes. In addition, both Master and Working Cell Banks maintained the defined cell viability and concentration over a 37 month-period after cryopreservation.

Conclusions

Manufacturing cell banks under Good Manufacturing Practice regulations for their use as raw materials or final cellular products is feasible. HEK293T cell banks were used to manufacture clinical-grade lentiviral particles for Chimeric Antigen Receptor T-cell based clinical trials.
Nutritive value and digestibility of macronutrients from sheep and alpaca skin hydrolysates as a new alternative in juvenile rainbow trout (Oncorhynchus mykiss) feeding
Authors: Araníbar-Araníbar Marcelino Jorge , Roque-Huanca Bernardo , Portocarrero-Prado Harnold Segundo , Rodríguez-Huanca Francisco Halley , del Pilar Blanco-Espezúa María , Araníbar-Béjar Heidi Karol , Foraquita-Choque Simón
Published: November 2020

Background

The protein source from fish meal is very important in trout feeding, but it is expensive and very scarce. Alternative nutrient sources are required to achieve sustainability as trout production rapidly grows in Peru. The objective of this research was to determine the proximate chemical composition and the apparent digestibility coefficient (ADC) of dry matter, organic matter, crude protein, crude fat, and digestible energy of hydrolyzed sheep (HSS) and alpaca (HSA) skins in juvenile rainbow trout.

Methods

A total of 450 fishes were randomly distributed in nine digestibility tanks, with 60.0 ± 1.32 g of initial weight and 6.4 kg/m3 of stocking density. The water quality parameters were as follows: pH 8.4, temperature 11.5 °C, and dissolved oxygen 6.2 mg/l. The skin hydrolysates were treated at 130 °C with 15 psi pressure for 120 min. Fish were fed a reference diet and an experimental diet containing 70% reference diet and 30% skin hydrolysate. The ingredients of the diets were mixed and then extruded at 95 °C with 4-mm diameter (Extruder Khal® EE800). The ADC was determined by the indirect method using insoluble ash as a non-digestible marker.

Results

The ADC in HSS and HSA was similar for dry matter (67.7 vs 69.1%), organic matter (66.9 vs 68.2%), crude protein (70.4 vs 70.1%), and digestible energy (3.35 vs 3.24 Mcal/kg DM), but crude fat values were different (12.3 vs 48.0%; p < 0.001, respectively).

Conclusion

The hydrolyzed sheep and alpaca skins had a high content of macronutrients with an acceptable apparent digestibility of nutrients, making them a viable alternative to improve the nutritive value of more economical feeds for rainbow trout feed.
RETRACTED ARTICLE: Does serum B lymphocyte chemoattractant protein13 (CXCL13) level correlate with parameters of disease activity and severity in rheumatoid arthritis? Clinical and musculoskeletal ultrasonographic assessment
Authors: Baraka Eman A. , Egilla Sami A. , Hamad Gamal A. , Khalil Maiada A. , Ahmed Shereen H. , Elbehisy Mona M.
Published: November 2020

Background

Rheumatoid arthritis (RA) affects about 1–3% of the population making it one of the most popular autoimmune diseases. Chemokines through switching on their receptors exert a climacteric role in RA pathogenesis. The purpose of this cross-sectional study was to quantify the serum levels of serum B lymphocyte chemoattractant protein13 (CXCL13) chemokine in recent onset RA patients and to correlate its levels with clinical, laboratory, and musculoskeletal ultrasonographic parameters (MSUS) of disease activity and severity.

Results

The mean serum CXCL13 value showed a significant increase in the RA patients (388.86 ± 283.63 pg/ml) than in the controls (62.94 ± 31.62 pg/ml) (P < 0.001). Highly active RA patients had significantly the highest mean of CXCL13 (mean ± SD 819.13 ± 191.05) compared with the moderately active RA patients (mean ± SD 284.95 ± 137.93) (P < 0.001) and the RA patients with low disease activity (mean ± SD 129.5 ± 21.27) (P < 0.001) and its levels were positively related with clinical disease activity and musculoskeletal ultrasonographic severity parameters.

Conclusion

Serum CXCL13 is correlated with clinical disease activity and MSUS disease severity that encourages its use for monitoring the activity and severity of synovitis in recent onset RA patients. Future studies to detect the effect of disease activity control by medications on CXCL13 levels and the effect of the CXCL13 antagonist on controlling RA disease activity and severity are recommended.
The Pax6 master control gene initiates spontaneous retinal development via a self-organising Turing network
Authors: Grocott Timothy , Lozano-Velasco Estefania , Mok Gi Fay , Münsterberg Andrea E.
Published: November 2020

Understanding how complex organ systems are assembled from simple embryonic tissues is a major challenge. Across the animal kingdom a great diversity of visual organs are initiated by a ‘master control gene’ called Pax6, which is both necessary and sufficient for eye development. Yet precisely how Pax6 achieves this deeply homologous function is poorly understood. Using the chick as a model organism, we show that vertebrate Pax6 interacts with a pair of morphogen-coding genes, Tgfb2 and Fst, to form a putative Turing network, which we have computationally modelled. Computer simulations suggest that this gene network is sufficient to spontaneously polarise the developing retina, establishing the eye's first organisational axis and prefiguring its further development. Our findings reveal how retinal self-organisation may be initiated independent of the highly ordered tissue interactions that help to assemble the eye in vivo. These results help to explain how stem cell aggregates spontaneously self-organise into functional eye-cups in vitro. We anticipate these findings will help to underpin retinal organoid technology, which holds much promise as a platform for disease modelling, drug development and regenerative therapies.
Snx3 is important for mammalian neural tube closure via its role in canonical and non-canonical WNT signaling
Authors: Brown Heather Mary , Murray Stephen A. , Northrup Hope , Au Kit Sing , Niswander Lee A.
Published: November 2020

Disruptions in neural tube (NT) closure result in neural tube defects (NTDs). To understand the molecular processes required for mammalian NT closure, we investigated the role of Snx3, a sorting nexin gene. Snx3−/− mutant mouse embryos display a fully-penetrant cranial NTD. In vivo, we observed decreased canonical WNT target gene expression in the cranial neural epithelium of the Snx3−/− embryos and a defect in convergent extension of the neural epithelium. Snx3−/− cells show decreased WNT secretion, and live cell imaging reveals aberrant recycling of the WNT ligand-binding protein WLS and mis-trafficking to the lysosome for degradation. The importance of SNX3 in WNT signaling regulation is demonstrated by rescue of NT closure in Snx3−/− embryos with a WNT agonist. The potential for SNX3 to function in human neurulation is revealed by a point mutation identified in an NTD-affected individual that results in functionally impaired SNX3 that does not colocalize with WLS and the degradation of WLS in the lysosome. These data indicate that Snx3 is crucial for NT closure via its role in recycling WLS in order to control levels of WNT signaling.
‘The long tail of Covid-19’ - The detection of a prolonged inflammatory response after a SARS-CoV-2 infection in asymptomatic and mildly affected patients
Authors: Doykov Ivan , Hällqvist Jenny , Gilmour Kimberly C. , Grandjean Louis , Mills Kevin , Heywood Wendy E.
Published: November 2020

‘Long Covid’, or medical complications associated with post SARS-CoV-2 infection, is a significant post-viral complication that is being more and more commonly reported in patients. Therefore, there is an increasing need to understand the disease mechanisms, identify drug targets and inflammatory processes associated with a SARS-CoV-2 infection. To address this need, we created a targeted mass spectrometry based multiplexed panel of 96 immune response associated proteins. We applied the multiplex assay to a cohort of serum samples from asymptomatic and moderately affected patients. All patients had tested positive for a SARS-CoV-2 infection by PCR and were determined to be subsequently positive for antibodies. Even 40-60 days post-viral infection, we observed a significant remaining inflammatory response in all patients. Proteins that were still affected were associated with the anti-inflammatory response and mitochondrial stress. This indicates that biochemical and inflammatory pathways within the body can remain perturbed long after SARS-CoV-2 infections have subsided even in asymptomatic and moderately affected patients.
PET measured hypoxia and MRI parameters in re-irradiated head and neck squamous cell carcinomas: findings of a prospective pilot study
Authors: Rogasch Julian , Beck Marcus , Stromberger Carmen , Hofheinz Frank , Ghadjar Pirus , Wust Peter , Budach Volker , Amthauer Holger , Tinhofer Ingeborg , Furth Christian , Walter-Rittel Thula C. , Zschaeck Sebastian
Published: November 2020

Background: Tumor hypoxia measured by dedicated tracers like [18F]fluoromisonidazole (FMISO) is a well-established prognostic factor in head and neck squamous cell carcinomas (HNSCC) treated with definitive chemoradiation (CRT). However, prevalence and characteristics of positron emission tomography (PET) measured hypoxia in patients with relapse after previous irradiation is missing. Here we report imaging findings of a prospective pilot study in HNSCC patients treated with re-irradiation.

Methods: In 8 patients with recurrent HNSCC, diagnosed at a median of 18 months after initial radiotherapy/CRT, [18F]fluorodeoxyglucose (FDG)-PET/CT (n=8) and FMISO-PET/MRI (n=7) or FMISO-PET/CT (n=1) were performed. Static FMISO-PET was performed after 180 min. MRI sequences in PET/MRI included diffusion-weighted imaging with apparent diffusion coefficient (ADC) values and contrast enhanced T1w imaging (StarVIBE). Lesions (primary tumor recurrence, 4; cervical lymph node, 1; both, 3) were delineated on FDG-PET and FMISO-PET data using a background-adapted threshold-based method. SUVmax and SUVmean in FDG- and FMISO-PET were derived, as well as maximum tumor-to-muscle ratio (TMRmax) and hypoxic volume with 1.6-fold muscle SUVmean (HV1.6) in FMISO-PET. Intensity of lesional contrast enhancement was rated relative to contralateral normal tissue. Average ADC values were derived from a 2D region of interest in the tumor.

Results: In FMISO-PET, median TMRmax was 1.7 (range: 1.1-1.8). Median HV1.6 was 0.05 ml (range: 0-7.3 ml). Only in 2/8 patients, HV1.6 was ≥1.0 ml. In FDG-PET, median SUVmax was 9.3 (range: 5.0-20.1). On contrast enhanced imaging four lesions showed decreased and four lesions increased contrast enhancement compared to non-pathologic reference tissue. Median average ADC was 1,060 ×106 mm2/s (range: 840-1,400 ×106 mm2/s).

Conclusions: This pilot study implies that hypoxia detectable by FMISO-PET may not be as prevalent as expected among loco-regional recurrent HNSCC. ADC values were only mildly reduced, and contrast enhancement was variable. The results require confirmation in larger sample sizes.
Mouth Cancer: the Maxillofacial Surgeon's perspective
Authors: Goodson Alexander MC , Parmar Satyesh , Praveen Prav , Idle Matthew , Martin Timothy
Published: November 2020

This article summarizes current practice according to UK guidelines for the management of oral cancer from the perspective of the oral and maxillofacial surgeon. The article discusses the patient pathway, starting with recognition of sinister features by the general dental practitioner in primary care and referral to specialist oral and maxillofacial surgery services, followed by the multidisciplinary approach to tumour staging, cancer treatment planning and delivery, and finally key issues in the ‘post-treatment’ phase of cancer care. Additional focus is provided for some of the surgical treatments and anatomical and physiological changes, of which the general dental practitioner should have some understanding.

CPD/Clinical Relevance: General dental practitioners play a key role in the detection and early management of oral cancer, referring approximately 40% of all cases to secondary care. It is therefore important to understand key milestones and technical elements of the patient's journey.
A Practical Guide to Caries Prevention in Children
Authors: Rashid Mishaal , Ellis Amy , Deery Chris
Published: November 2020

Caries is one of the most common diseases in the world and it is mostly preventable. Caries can have a large impact on a child's physical, social and mental health. There are a number of clinical interventions available to prevent caries and this article provides a summary of the general guidelines and tips on their implementation in relation to caries prevention in children.

CPD/Clinical Relevance: This article highlights the importance of caries prevention and the relevant interventions, especially in the context of limited access to health services. These guidelines can be beneficial for all dental health professionals.
Comprehensive Assessment of Individuals With Significant Levels of Intellectual Disability: Challenges, Strategies, and Future Directions
Authors: DiStefano Charlotte , Sadhwani Anjali , Wheeler Anne C.
Published: November 2020

The variety and extent of impairments in individuals with severe-profound levels of intellectual disability (ID) impact their ability to complete valid behavioral assessments. Although standardized assessment is crucial for objectively evaluating patients, many individuals with severe-profound levels of ID perform at the floor of most assessments designed for their chronological age. Additionally, the presence of language and motor impairments may influence the individual's ability to perform a task, even when that task is meant to measure an unrelated construct leading to an underestimation of their true ability. This article provides an overview of the assessment protocols used by multiple groups working with individuals with severe-profound levels of ID, discusses considerations for obtaining high-quality assessment results, and suggests guidelines for standardizing these protocols across the field.
Development of Neural Response to Novel Sounds in Fragile X Syndrome: Potential Biomarkers
Authors: Ethridge Lauren , Thaliath Andrew , Kraff Jeremy , Nijhawan Karan , Berry-Kravis Elizabeth
Published: November 2020

Auditory processing abnormalities in fragile X syndrome (FXS) may contribute to difficulties with language development, pattern identification, and contextual updating. Participants with FXS (N = 41) and controls (N = 27) underwent auditory event-related potentials during presentation of an oddball paradigm. Data was adequate for analysis for 33 participants with FXS and 27 controls (age 4–51 y, 13 females [FXS]; 4–54 y, 11 females [control]). Participants with FXS showed larger N1 and P2 amplitudes, abnormal lack of modulation of P1 and P2 amplitudes and P2 latency in response to oddball stimuli ) relative to controls: Females with FXS were more similar to controls. Participants with FXS showed a marginal speeding of the P2 latency, suggesting potentiation to oddball stimuli rather than habituation. Participants with FXS showed a heightened N1 habituation effect compared to controls. Gamma power was significantly higher for participants with FXS. Groups did not differ on mismatch negativity. Both controls and participants with FXS showed similar developmental trajectories in P1 and N1 amplitude, P2 latency, and gamma power, but not for P2 amplitude. One month retest analyses performed in 14 participants suggest strong test-retest reliability for most measures. Individuals with FXS show previously demonstrated increased response amplitude and high frequency neural activity. Despite an overall normal developmental trajectory for most measures, individuals with FXS show age-independent but gender-dependent decreases in complex processing of novel stimuli. Many markers show strong retest reliability even in children and thus are potential biomarkers for clinical trials in FXS.
Psychophysiological and Eye-Tracking Markers of Speech and Language Processing in Neurodevelopmental Disorders: New Options for Difficult-to-Test Populations
Authors: Key Alexandra P. , Venker Courtney E. , Sandbank Micheal P.
Published: November 2020

It can be challenging to accurately assess speech and language processing in preverbal or minimally verbal individuals with neurodevelopmental disabilities (NDD) using standardized behavioral tools. Event-related potential and eye tracking methods offer novel means to objectively document receptive language processing without requiring purposeful behavioral responses. Working around many of the cognitive, motor, or social difficulties in NDDs, these tools allow for minimally invasive, passive assessment of language processing and generate continuous scores that may have utility as biomarkers of individual differences and indicators of treatment effectiveness. Researchers should consider including physiological measures in assessment batteries to allow for more precise capture of language processing in individuals for whom it may not behaviorally apparent.
Measuring Change in the Communication Skills of Children With Autism Spectrum Disorder Using the Communication Complexity Scale
Authors: Brady Nancy C. , Romine Rebecca E. Swinburne , Holbrook Alison , Fleming Kandace K. , Kasari Connie
Published: November 2020

Changes in minimal verbal communication by children with autism spectrum disorder (ASD) were measured with the Communication Complexity Scale (CCS) and other communication assessments. The CCS measures complexity of preverbal and beginning verbal communication used to communicate behavior regulation and joint attention. The purpose was to investigate if the CCS was responsive to changes associated with a behavioral intervention aimed at improving communication skills. Changes were detected with CCS scores, rates of initiating joint attention, and the Mullen Scales of Early Learning (MSEL) Expressive Language subscale. Significant changes in CCS scores were also detected for a subgroup of participants who did not show significant changes on the MSEL Expressive Language subscale, demonstrating that CCS scores are sensitive to changes associated with a behavioral intervention.
Fundamental precision bounds for three-dimensional optical localization microscopy using self-interference digital holography
Authors: Marar Abhijit , Kner Peter
Published: November 2020

Localization based microscopy using self-interference digital holography (SIDH) provides three-dimensional (3D) positional information about point sources with nanometer scale precision. To understand the performance limits of SIDH, here we calculate the theoretical limit to localization precision for SIDH when designed with two different configurations. One configuration creates the hologram using a plane wave and a spherical wave while the second configuration creates the hologram using two spherical waves. We further compare the calculated precision bounds to the 3D single molecule localization precision from different Point Spread Functions. SIDH results in almost constant localization precision in all three dimensions for a 20 µm thick depth of field. For high signal-to-background ratio (SBR), SIDH on average achieves better localization precision. For lower SBR values, the large size of the hologram on the detector becomes a problem, and PSF models perform better.
Adaptive optics enables aberration-free single-objective remote focusing for two-photon fluorescence microscopy
Authors: Yang Yuhan , Chen Wei , Fan Jiang Lan , Ji Na
Published: November 2020

Two-photon fluorescence microscopy has been widely applied to three-dimensional (3D) imaging of complex samples. Remote focusing by controlling the divergence of excitation light is a common approach to scanning the focus axially. However, microscope objectives induce distortion to the wavefront of non-collimated excitation beams, leading to degraded imaging quality away from the natural focal plane. In this paper, using a liquid-crystal spatial light modulator to control the divergence of the excitation beam through a single objective, we systematically characterized the aberrations introduced by divergence control through microscope objectives of NA 0.45, 0.8, and 1.05. We used adaptive optics to correct the divergence-induced-aberrations and maintain diffraction-limited focal quality over up to 800-µm axial range. We further demonstrated aberration-free remote focusing for in vivo imaging of neurites and synapses in the mouse brain.
Correcting intra-volume distortion for AO-OCT using 3D correlation based registration
Authors: Li Zhenghan , Pandiyan Vimal Prabhu , Maloney-Bertelli Aiden , Jiang Xiaoyun , Li Xinyang , Sabesan Ramkumar
Published: November 2020

Adaptive optics (AO) based ophthalmic imagers, such as scanning laser ophthalmoscopes (SLO) and optical coherence tomography (OCT), are used to evaluate the structure and function of the retina with high contrast and resolution. Fixational eye movements during a raster-scanned image acquisition lead to intra-frame and intra-volume distortion, resulting in an inaccurate reproduction of the underlying retinal structure. For three-dimensional (3D) AO-OCT, segmentation-based and 3D correlation based registration methods have been applied to correct eye motion and achieve a high signal-to-noise ratio registered volume. This involves first selecting a reference volume, either manually or automatically, and registering the image/volume stream against the reference using correlation methods. However, even within the chosen reference volume, involuntary eye motion persists and affects the accuracy with which the 3D retinal structure is finally rendered. In this article, we introduced reference volume distortion correction for AO-OCT using 3D correlation based registration and demonstrate a significant improvement in registration performance via a few metrics. Conceptually, the general paradigm follows that developed previously for intra-frame distortion correction for 2D raster-scanned images, as in an AOSLO, but extended here across all three spatial dimensions via 3D correlation analyses. We performed a frequency analysis of eye motion traces before and after intra-volume correction and revealed how periodic artifacts in eye motion estimates are effectively reduced upon correction. Further, we quantified how the intra-volume distortions and periodic artifacts in the eye motion traces, in general, decrease with increasing AO-OCT acquisition speed. Overall, 3D correlation based registration with intra-volume correction significantly improved the visualization of retinal structure and estimation of fixational eye movements.
Young’s double-slit experiment with a partially coherent vortex beam
Authors: Chen Tianchi , Lu Xingyuan , Zeng Jun , Wang Zhuoyi , Zhang Hao , Zhao Chengliang , Hoenders Bernhard J. , Cai Yangjian
Published: November 2020

We perform a Young’s double-slit experiment with a partially coherent vortex beam (PCVB) and explore its cross-spectral density (CSD) at the focal plane after passing through a double-slit. Our results reveal that the phase of the CSD distribution with respect to an on-axis reference point can simultaneously quantitatively characterize the sign and magnitude of the topological charge (TC) carried by such a beam. In particular, the magnitude of the TC is half of the number of coherence singularities and the sign of the TC is determined by the phase winding of the coherence singularities (i.e., counterclockwise- and clockwise increases correspond to positive and negative, respectively). Based on this property, we present and demonstrate experimentally a simple technique to measure the sign and magnitude of the TC of a PCVB through its CSD distribution after a double-slit. Our method allows for easy measurement of the TC by being conceptually simpler than other methods.
Effective photon recycling in solar thermophotovoltaics using a confined cuboid emitter
Authors: Kohiyama Asaka , Shimizu Makoto , Konno Kana , Furuhashi Tomoya , Yugami Hiroo
Published: November 2020

For effective photon conversion in solar-thermophotovoltaic (TPV) systems, an enclosed-space confined emitter system is proposed, and its power generation potential is demonstrated. A cuboid monolithic absorber/emitter is applied for higher extraction efficiency without dead areas. An analysis using an enclosed space shows a 4.1% higher absolute system efficiency than that using a planar absorber/emitter system. In the experiment, system efficiency reaches 7.0%, which is obtained after multiplying the power measured from one cell by five. A system efficiency more than 20% is achievable by further improvement with a back surface reflecting TPV cells and a perfectly enclosed space.
Tool path generation of turning optical freeform surfaces using arbitrary rake angle tools
Authors: You Kaiyuan , Yan Guangpeng , Fang Fengzhou , Li Zexiao , Zhang Yue
Published: November 2020

Slow tool servo diamond turning has widespread application in fabricating freeform optics. Previous studies are focused on the methods of the tool path generation and verification of zero-rake-angle tools. However, these methods are unsuitable for non-zero-rake tools that are used for machining hard-and-brittle materials. This paper presents a universal location-point-drive tool path generation method, which caters to arbitrary rake angle tools and the steady X movement feature, and the corresponding universal tool interference check method. Systematic analysis and ultra-precision machining experiments confirmed the feasibility of our methods and present better surface quality and form accuracy compared to the traditional method.
Light-field multi-spectral radiation thermometry
Authors: Luan Yinsen , Mei Di , Shi Shengxian
Published: November 2020

This Letter proposes light-field multi-spectral radiation thermometry based on an unfocused light-field camera, which can simultaneously record directions and intensities of incident rays. In this method, the direction information of rays is substituted by radiation spectrums via placing an array of filters in front of camera main lens, such that the image sensor can simultaneously acquire spectrums and intensities of rays. By decoupling a raw multi-spectral light-field (MSLF) image and utilizing traditional multi-wavelength pyrometer algorithms, the scalar field of surface temperature distribution can be achieved. To verify the method, measurement errors of different temperature levels on several typical areas of MSLF images are analyzed. In addition, the validation experiment demonstrates that accurate surface temperature measurement can be achieved with a single lens, single monochromatic image sensor, and just one snapshot in the proposed method.
Low-cost single-point optoacoustic sensor for spectroscopic measurement of local vascular oxygenation
Authors: Stylogiannis Antonios , Riobo Lucas , Prade Ludwig , Glasl Sarah , Klein Sabine , Lucidi Giulia , Fuchs Martin , Saur Dieter , Ntziachristos Vasilis
Published: November 2020

Optical sensors developed for the assessment of oxygen in tissue microvasculature, such as those based on near-infrared spectroscopy, are limited in application by light scattering. Optoacoustic methods are insensitive to light scattering, and therefore, they can provide higher specificity and accuracy when quantifying local vascular oxygenation. However, currently, to the best of our knowledge, there is no low-cost, single point, optoacoustic sensor for the dedicated measurement of oxygen saturation in tissue microvasculature. This work introduces a spectroscopic optoacoustic sensor (SPOAS) for the non-invasive measurement of local vascular oxygenation in real time. SPOAS employs continuous wave laser diodes and measures at a single point, which makes it low-cost and portable. The SPOAS performance was benchmarked using blood phantoms, and it showed excellent linear correlation (

R

2

=

0.98

) with a blood gas analyzer. Subsequent measurements of local vascular oxygenation in living mice during an oxygen stress test correlated well with simultaneous readings from a reference instrument.
Energy deposition parameters revealed in the transition from 3D to 1D femtosecond laser ablation of fluorite at high-NA focusing
Authors: Kudryashov Sergey , Danilov Pavel , Rupasov Alexey , Khonina Svetlana , Nalimov Anton , Ionin Andrey , Krasin George , Kovalev Michael
Published: November 2020

Ultrashort-pulse laser surface and bulk nano- and micromachining of dielectrics have multiple promising applications in micro-optics, microfluidics, and memory storage. The fundamental principles relate intrinsic inter-band multi-photon (MPA) and laser-induced intra-band free-carrier absorption (FCA) to particular ablation mechanisms and features. These principles are yet to be quantified into a complete set of basic experimental laser-matter interaction parameters, describing photoexcitation, relaxation, and final ablation. In this study, we considered the characteristic double-crater structure of single-shot ablation spots on dielectric surfaces and single-shot transmission spectra to extract crucial information about the underlying basic processes of ultrafast photoexcitation and laser energy deposition. Specifically, energy-dependent crater profiles and accompanying prompt self-phase modulation (SPM) spectral broadening were studied in single-shot surface ablation experiments on fluorite (CaF2) surface photo-excited by tightly focused 515- or 1030-nm, 300-fs laser pulses. Crater size dependence demonstrated two slopes, scaling proportionally to the squared focal 1/e-radius at higher energies (intensities) for larger ablated spots, and a much smaller squared 1/e-radius at lower energies (intensities) for (sub) micron-wide ablated spots, indicating a transition from 1D to 3D-ablation. As a result, these slopes were related to lower-intensity wavelength-dependent multi-photon inter-band transitions and wavelength-independent higher-intensity linear absorption in the emerging near-critical electron-hole plasma (EHP), respectively. Crater depth dependences on the local laser intensity fitted in the corresponding ranges by multi- and one-photon absorption provided the corresponding absorption coefficients. Spectral broadening measurements indicated even values for the red and blue shoulders of the laser pulse spectrum, representing the SPM effect in the weakly excited fluorite at the leading pulse front and providing the corresponding Kerr coefficient. In the second regime, the blue-shoulder broadening value saturated, indicating the appearance of near-critical plasma screening at the trailing pulse front, which is consistent with our calculations. These complementary experiments and related analysis provided an important set of key basic parameters, characterizing not only surface ablation, but also propagation of high-intensity ultrashort laser pulses in bulk fluorite, and enabling precise forecasting of optimal energy deposition for high-efficiency ultrashort-laser micro-structuring of this dielectric material.
Modeling HIV-1 infection in the brain
Authors: Barker Colin T. , Vaidya Naveen K.
Published: November 2020

While highly active antiretroviral therapy (HAART) is successful in controlling the replication of Human Immunodeficiency Virus (HIV-1) in many patients, currently there is no cure for HIV-1, presumably due to the presence of reservoirs of the virus. One of the least studied viral reservoirs is the brain, which the virus enters by crossing the blood-brain barrier (BBB) via macrophages, which are considered as conduits between the blood and the brain. The presence of HIV-1 in the brain often leads to HIV associated neurocognitive disorders (HAND), such as encephalitis and early-onset dementia. In this study we develop a novel mathematical model that describes HIV-1 infection in the brain and in the plasma coupled via the BBB. The model predictions are consistent with data from macaques infected with a mixture of simian immunodeficiency virus (SIV) and simian-human immunodeficiency virus (SHIV). Using our model, we estimate the rate of virus transport across the BBB as well as viral replication inside the brain, and we compute the basic reproduction number. We also carry out thorough sensitivity analysis to define the robustness of the model predictions on virus dynamics inside the brain. Our model provides useful insight into virus replication within the brain and suggests that the brain can be an important reservoir causing long-term viral persistence.
Effects of the invasive plant Xanthium strumarium on diversity of native plant species: A competitive analysis approach in North and Northeast China
Authors: Iqbal Mazher Farid , Liu Ming-Chao , Iram Aafia , Feng Yu-Long
Published: November 2020

Xanthium strumarium is native to North America and now has become one of the invasive alien species (IAS) in China. In order to detect the effects of the invader on biodiversity and evaluate its suitable habitats and ecological distribution, we investigated the abundance, relative abundance, diversity indices, and the number of the invasive and native plants in paired invaded and non-invaded quadrats in four locations in North and Northeast China. We also analyzed the effects of monthly mean maximum and minimum temperatures, relative humidity (%), and precipitations (mm). Strong positive significant (P < 0.01) correlation and maximum interspecific competition (41%) were found in Huailai between invaded and non-invaded quadrats. Shannon’s Diversity Index showed that non-invaded plots had significantly (P < 0.05) more diversified species than invaded ones. The significant (P < 0.05) Margalef’s Richness Index was found in Huailai and Zhangjiakou in non-invaded recorded heterogeneous nature of plant communities. Similarly, significant (P < 0.05) species richness found in Huailai and Zhangjiakou in non-invaded quadrats compared to invaded ones. Maximum evenness of Setaria feberi (0.47, 0.37), Seteria viridis (0.43) found in Fushun and Zhangjiakou recorded more stable in a community compared to other localities. Evenness showed positive relationship of Shannon Entropy within different plant species. The higher dissimilarity in plant communities found in Huailai (87.06%) followed by Yangyuan (44.43%), Zhangjiakou (40.13%) and Fushun (29.02%). The significant (P < 0.01) value of global statistics R (0.943/94.3%) showed high species diversity recorded in Huailai followed by Zhangjiakou recorded by non-metric multidimensional scaling and analysis of similarity between invaded and non-invaded plots. At the end it was concluded that the diversity indices reduced significantly (P < 0.05) in invaded quadrats indicated that native plant species become less diverse due to X. strumarium invasion. The degrees of X. strumarium invasion affected on species richness resulted to reduce diversity indices significantly in invaded quadrats.
Comparison of MR findings of acute traumatic peripheral nerve injury and acute compressive neuropathy in a rat model
Authors: Kim Bo Ra , Ha Dong-Ho , Kim Jong Kuk , Kim Young Hee
Published: November 2020

Purpose

The treatment strategy is different for acute traumatic peripheral nerve injury and acute compressive neuropathy. This study aimed to compare magnetic resonance imaging (MRI) features of acute traumatic peripheral nerve injury and acute compressive neuropathy in a rat model.

Materials and methods

Twenty female Sprague-Dawley rats were divided into two groups. In the crush injury group (n = 10), the unilateral sciatic nerve was crushed using forceps to represent acute traumatic peripheral nerve injury. In the compression injury group (n = 10), the unilateral sciatic nerve was ligated using silk to represent acute compressive neuropathy. The MRI of eight rats from each group were acquired on postoperative days 3 and 10. Fat-suppressed T2-weighted images were acquired. Changes in the injured nerve were divided into three grades. A Fisher’s exact test was used to compare the changes in the nerves of the two groups. Histological staining and a western blot analysis were performed on one rat in each group on day 3. Neurofilament, myelin basic protein (MBP), and p75NTR staining were performed. Expression of neurofilament, MBP, p75NTR, and c-jun was evaluated by western blot analysis.

Results

MR neurography revealed substantial nerve changes in the compression injury group compared with the crush injury group at two-time points (p = 0.001 on day 3, p = 0.026 on day 10). The histopathological analysis indicated the destruction of the axon and myelin, mainly at the injury site and the distal portion of the injury in the crush injury group. It was prominent in the proximal portion, the injury site, and the distal portion of the injury in the compression injury group. The degree of axonal and myelin destruction was more pronounced in the compression injury group than in the crush injury group.

Conclusion

MR neurography showed prominent and long-segmental changes associated with the injured nerve in acute compressive neuropathy compared with acute traumatic peripheral nerve injury.
Quantifying myelin content in brain tissue using color Spatial Light Interference Microscopy (cSLIM)
Authors: Fanous Michael , Caputo Megan P. , Lee Young Jae , Rund Laurie A. , Best-Popescu Catherine , Kandel Mikhail E. , Johnson Rodney W. , Das Tapas , Kuchan Matthew J. , Popescu Gabriel
Published: November 2020

Deficient myelination of the brain is associated with neurodevelopmental delays, particularly in high-risk infants, such as those born small in relation to their gestational age (SGA). New methods are needed to further study this condition. Here, we employ Color Spatial Light Interference Microscopy (cSLIM), which uses a brightfield objective and RGB camera to generate pathlength-maps with nanoscale sensitivity in conjunction with a regular brightfield image. Using tissue sections stained with Luxol Fast Blue, the myelin structures were segmented from a brightfield image. Using a binary mask, those portions were quantitatively analyzed in the corresponding phase maps. We first used the CLARITY method to remove tissue lipids and validate the sensitivity of cSLIM to lipid content. We then applied cSLIM to brain histology slices. These specimens are from a previous MRI study, which demonstrated that appropriate for gestational age (AGA) piglets have increased internal capsule myelination (ICM) compared to small for gestational age (SGA) piglets and that a hydrolyzed fat diet improved ICM in both. The identity of samples was blinded until after statistical analyses.