bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of Magnetic Fields (0.05 T ≤ B ≤ 7 T) on the Response of Personal Thermoluminescent Dosimeters to Ionizing Radiation
Authors: Copty Atallah , Rabineg Günter , Berg Andreas 
Published: May 2019

Abstract
We investigated the main question of whether thermoluminescent dosimeters indicate the correct dose when exposed to magnetic fields from low stray fields up to high magnetic resonance imaging fields inside human magnetic resonance imaging scanners (0.05 T ≤ B ≤ 7 T) during and after irradiation. Medical personnel working in radiology, oncology, or nuclear medicine are regularly monitored with thermoluminescent dosimeters. They might also enter the magnetic field of a magnetic resonance imaging scanner while supervising patients as well as during positron emission tomography-magnetic resonance imaging and magnetic resonance imaging-linac integrated imaging systems and will therefore be exposed to the magnetic fields of magnetic resonance imaging scanners and low stray fields of several millitesla outside of the magnetic resonance imaging scanner, not only before and after, but also during irradiation. Panasonic thermoluminescent dosimetry badges and ring dosimeters for personal monitoring were exposed to magnetic fields originating from a 7 T and a 3 T magnetic resonance imaging scanner as well as neodymium permanent magnets. Four different sealed 137Cs sources were used in two sets of experiments: (1) magnetically induced fading: irradiated thermoluminescent dosimeters (D ≈ 100 mSv) were exposed to a strong magnetic field (B = 7 T) of a human high-field magnetic resonance imaging scanner after irradiation; no magnetically induced fading (magnetoluminescence) for LiBO:Cu or CaSO:Tm was observed; (2) magnetically induced attenuation: thermoluminescent dosimeters were placed during irradiation in a magnetic field for about 60 h; a significantly reduced dose response was observed for LiBO:Cu—interestingly not at maximum B ≈ 7 T but at B ≈ 0.2 T. This experimental observation is possibly relevant especially for medical and technical personnel in nuclear medicine before and during a magnetic resonance imaging scanning procedure. Follow-up studies need to be made to clarify the kinetics of this effect.
Developing Detection DecisioNS on the Absence or Presence of a Radiological Source using a Bayesian Interaction Model
Authors: Brogan John , Brandl Alexander 
Published: May 2019

Abstract
Bayesian statistics have been used in various health physics applications, but only limited material exists on the development of a decision threshold for simple gross count measurements using Bayesian statistics. Bayesian modeling specifies a logical procedure for processing information and provides the means to obtain abstract statistical knowledge about the data in question. A Bayesian interaction model was developed to analyze gross count measurements. This linear regression model studies the relationship between a gross count measurement and the standard deviation of the gross counts obtained in the current and the previous four measurements, and conditions the analysis on whether the data originate from background measurements or from measurements with a source present. The measure of that relationship is expressed statistically by the constructed parameter ζ, which in the Bayesian framework possesses a probability distribution that can be used to achieve detection decisions. The model was validated statistically and under operationally equivalent conditions. Specifically, it was applied to analyze sequential data obtained from continuous gross count measurements at fixed time intervals. The Bayesian analysis used five sequential measurements per detection decision. The model performs optimally for weaker source detections, and presents promising operational application. Its usefulness derives from the facts that an established training data set is not necessary, long-run background measurements are not required to establish parameter estimates, and ζ and the model are universally applicable such that their use is not limited to the predictor variable presented here.
STRICT POSTURING WITH OR WITHOUT BILATERAL PATCHING FOR POSTERIOR VITREOUS DETACHMENT–RELATED VITREOUS HEMORRHAGE
Authors: van Etten Peter G. , van Overdam Koen A. , Reyniers Rudolf , Veckeneer Marc , Faridpooya Koorosh , Wubbels René J. , Manning Sonia , La Heij Ellen C. , van Meurs Jan C. 
Published: May 2019

Purpose:
To determine whether bilateral patching with posturing is superior to posturing alone in visualizing the superior retina in suspected posterior vitreous detachment (PVD)–related vitreous hemorrhage (VH).

Methods:
Prospective randomized controlled trial: 80 patients with fundus-obscuring VH due to suspected retinal tear were randomized to strict posturing and bilateral patching overnight (Treatment A, 40 patients) or posturing (Treatment B, 40 patients).

Primary outcome:
Visualization of ≥4 clock hours superior retina. Secondary outcome measures: laser treatment, vitrectomy rate, and retinal detachment within 12 months.

Results:
Intention-to-treat analysis: In 38/40 (95%) with Treatment A and 32/40 (80%) with Treatment B, the confirmed diagnosis was PVD-related VH. Visibility of the superior retina for all patients: 29/40 (73%) after Treatment A and 21/40 (53%) after Treatment B (P = 0.07). Subgroup analysis for confirmed PVD-related VH; visibility of the superior retina: 29/38 (76%) after Treatment A and 15/32 (47%) after Treatment B (P = 0.01). In subgroup analysis, vitrectomy rate within 12 months was 61% (Treatment A) and 53% (Treatment B) (P = 0.63). Retinal detachment: eight patients after each treatment.

Conclusion:
In patients with suspected PVD-related VH, overnight bilateral patching was not superior to posturing alone in superior retina visualization, but in a post-hoc analysis of patients with confirmed PVD-related VH, bilateral patching was superior.
EN FACE IMAGE–BASED ANALYSIS OF RETINAL TRACTION CAUSED BY EPIRETINAL MEMBRANE AND ITS RELATIONSHIP WITH VISUAL FUNCTIONS
Authors: Hirano Masayuki , Morizane Yuki , Kanzaki Yuki , Kimura Shuhei , Hosokawa Mio , Shiode Yusuke , Doi Shinichiro , Toshima Shinji , Takahashi Kosuke , Hosogi Mika , Fujiwara Atsushi , Takasu Ippei , Shiraga Fumio 
Published: May 2019

Purpose:
To evaluate the relationship between retinal traction caused by epiretinal membrane and visual functions.

Methods:
In this institutional study, en face swept-source optical coherence tomography images of 141 eyes of 130 patients with epiretinal membrane were analyzed to investigate maximum depth of retinal folds, which represents retinal traction strength and the distribution pattern of retinal folds. We investigated the relationships between the maximum depth and distribution pattern of retinal folds and visual functions as well as the effects of membrane peeling.

Results:
Maximum retinal fold depth was significantly correlated with the metamorphopsia score (P < 0.001). Fifteen eyes showed retinal folds radially extending from the macular epiretinal membrane (radiating folds group), whereas 126 eyes showed a multidirectional pattern of retinal folds (multidirectional folds group). The radiating folds group showed a significantly lower metamorphopsia score (P = 0.014). Multiple regression analysis revealed that the metamorphopsia score was significantly related to maximum retinal fold depth (P = 0.003), distribution pattern (P = 0.015), and central retinal thickness (P < 0.001). One month after membrane peeling, parafoveal retinal folds resolved completely in all cases, and both visual acuity (P < 0.001) and average metamorphopsia score (P = 0.036) were significantly improved.

Conclusion:
Both the strength and the distribution pattern of retinal traction are significantly related to metamorphopsia in epiretinal membrane patients.
Portopulmonary Hypertension: A Survey of Practice Patterns and Provider Attitudes
Authors: DuBrock Hilary M. , Salgia Reena J. , Sussman Norman L. , Bartolome Sonja D. , Kadry Zakiyah , Mulligan David C. , Jenkins Sarah , Lackore Kandace , Channick Richard N. , Kawut Steven M. , Krowka Michael J. 
Published: May 2019

Background.
The role of liver transplantation (LT) in the management of portopulmonary hypertension (POPH) is poorly understood. The aim of this study was to better understand provider attitudes and practice patterns regarding the management of patients with POPH and to assess the concordance between clinical practice and current guidelines.

Methods.
We performed a multicenter survey study of hepatologists and pulmonary hypertension (PH) physicians at US LT centers that performed >50 transplants per year. Survey responses are summarized as number (%). Associations were assessed using a Wilcoxon-rank sum, chi-square, or Fisher exact test, as appropriate.

Results.
Seventy-four providers from 35 centers were included. There was marked variability regarding screening practices, management, and attitudes. Forty-two percent responded that POPH nearly always or often improves with LT, and 15.5% reported that POPH rarely or never improves. In contrast to current guidelines, 50.7% agreed that treated POPH should be an indication for LT in patients with compensated cirrhosis. Hepatologists were more likely than PH physicians to agree that POPH should be an indication for LT (P = 0.02). Forty-nine percent of respondents thought that the current POPH Model for End-stage Liver Disease exception criteria should be modified, and management of patients with an elevated mean pulmonary arterial pressure and normal pulmonary vascular resistance differed from current policies.

Conclusions.
There is marked variability in provider attitudes and practice patterns regarding the management of POPH. This study highlights the need for prospective studies to inform practice and for improved implementation of practice guidelines in order to standardize care.
Strong magnetic exchange and frustrated ferrimagnetic order in a weberite-type inorganic–organic hybrid fluoride
Authors: Clark L. , Albino M. , Pimenta V. , Lhoste J. , da Silva I. , Payen C. , Grenèche J.-M. , Maisonneuve V. , Lightfoot P. , Leblanc M. 
Published: May 2019

We combine powder neutron diffraction, magnetometry and
57
Fe Mössbauer spectrometry to determine the nuclear and magnetic structures of a strongly interacting weberite-type inorganic–organic hybrid fluoride, Fe
2
F
5
(H
taz
). In this structure, Fe
2+
and Fe
3+
cations form magnetically frustrated hexagonal tungsten bronze layers of corner-sharing octahedra. Our powder neutron diffraction data reveal that, unlike its purely inorganic fluoride weberite counterparts which adopt a centrosymmetric
Imma
structure, the room-temperature nuclear structure of Fe
2
F
5
(H
taz
) is best described by a non-centrosymmetric
Ima
2 model with refined lattice parameters
a
= 9.1467(2) Å,
b
= 9.4641(2) Å and
c
= 7.4829(2) Å. Magnetic susceptibility and magnetization measurements reveal that strong antiferromagnetic exchange interactions prevail in Fe
2
F
5
(H
taz
) leading to a magnetic ordering transition at
T
N
= 93 K. Analysis of low-temperature powder neutron diffraction data indicates that below
T
N
, the Fe
2+
sublattice is ferromagnetic, with a moment of 4.1(1)

µ
B

per Fe
2+
at 2 K, but that an antiferromagnetic component of 0.6(3)

µ
B

cants the main ferromagnetic component of Fe
3+
, which aligns antiferromagnetically to the Fe
2+
sublattice. The zero-field and in-field Mössbauer spectra give clear evidence of an excess of high-spin Fe
3+
species within the structure and a non-collinear magnetic structure.

This article is part of the theme issue ‘Mineralomimesis: natural and synthetic frameworks in science and technology’.
Prospects for electroactive and conducting framework materials
Authors: Murase Ryuichi , Ding Bowen , Gu Qinyi , D'Alessandro Deanna M. 
Published: May 2019

Electroactive and conducting framework materials, encompassing coordination polymers and metal–organic frameworks, have captured the imagination of the scientific community owing to their highly designable nanoporous structures and their potential applications in electrochromic devices, electrocatalysts, porous conductors, batteries and solar energy harvesting systems, among many others. While they are now considered integral members of the broader field of inorganic materials, it is timely to reflect upon their strengths and challenges compared with ‘traditional’ solid-state materials such as minerals, pigments and zeolites. Indeed, the latter have been known since ancient times and have been prized for centuries in fields as diverse as art, archaeology and industrial catalysis. This opinion piece considers a brief historical perspective of traditional electroactive and conducting inorganic materials, with a view towards very recent experimental progress and new directions for future progress in the burgeoning area of coordination polymers and metal–organic frameworks. Overall, this article bears testament to the rich history of electroactive solids and looks at the challenges inspiring a new generation of scientists.
This article is part of the theme issue ‘Mineralomimesis: natural and synthetic frameworks in science and technology’.
Hydrogen-bond-mediated structural variation of metal guanidinium formate hybrid perovskites under pressure
Authors: Yang Zhengqiang , Cai Guanqun , Bull Craig L. , Tucker Matthew G. , Dove Martin T. , Friedrich Alexandra , Phillips Anthony E. 
Published: May 2019

The hybrid perovskites are coordination frameworks with the same topology as the inorganic perovskites, but with properties driven by different chemistry, including host-framework hydrogen bonding. Like the inorganic perovskites, these materials exhibit many different phases, including structures with potentially exploitable functionality. However, their phase transformations under pressure are more complex and less well understood. We have studied the structures of manganese and cobalt guanidinium formate under pressure using single-crystal X-ray and powder neutron diffraction. Under pressure, these materials transform to a rhombohedral phase isostructural to cadmium guanidinium formate. This transformation accommodates the reduced cell volume while preserving the perovskite topology of the framework. Using density-functional theory calculations, we show that this behaviour is a consequence of the hydrogen-bonded network of guanidinium ions, which act as struts protecting the metal formate framework against compression within their plane. Our results demonstrate more generally that identifying suitable host–guest hydrogen-bonding geometries may provide a route to engineering hybrid perovskite phases with desirable crystal structures.
This article is part of the theme issue ‘Mineralomimesis: natural and synthetic frameworks in science and technology’.
The olfactory basis of orchid pollination by mosquitoes
Authors: Lahondère Chloé , Vinauger Clément , Okubo Ryo P. , Wolff Gabriella H. , Chan Jeremy K. , Akbari Omar S. , Riffell Jeffrey A. 
Published: May 2019

AbstractMosquitoes are important vectors of disease and require sources of carbohydrates for reproduction and survival. Unlike host-related behaviors of mosquitoes, comparatively less is understood about the mechanisms involved in nectar-feeding decisions, or how this sensory information is processed in the mosquito brain. Here we show that Aedes spp. mosquitoes, including Aedes aegypti, are effective pollinators of the Platanthera obtusata orchid, and demonstrate this mutualism is mediated by the orchid’s scent and the balance of excitation and inhibition in the mosquito’s antennal lobe (AL). The P. obtusata orchid emits an attractive, nonanal-rich scent, whereas related Platanthera species – not visited by mosquitoes – emit scents dominated by lilac aldehyde. Calcium imaging experiments in the mosquito AL revealed that nonanal and lilac aldehyde each respectively activate the LC2 and AM2 glomerulus, and remarkably, the AM2 glomerulus is also sensitive to DEET, a mosquito repellent. Lateral inhibition between these two glomeruli reflects the level of attraction to the orchid scents: whereas the enriched nonanal scent of P. obtusata activates the LC2 and suppresses AM2, the high level of lilac aldehyde in the other orchid scents inverts this pattern of glomerular activity, and behavioral attraction is lost. These results demonstrate the ecological importance of mosquitoes beyond operating as disease vectors and open the door towards understanding the neural basis of mosquito nectar-seeking behaviors.Significance StatementNectar-feeding by mosquitoes is important for survival and reproduction, and hence disease transmission. However, we know little about the sensory mechanisms that mediate mosquito attraction to sources of nectar, like those of flowers, or how this information is processed in the mosquito brain. Using a unique mutualism between Aedes mosquitoes and Platanthera obtusata orchids, we reveal that this mutualism is mediated by the orchid’s scent. Furthermore, lateral inhibition in the mosquito’s antennal (olfactory) lobe – via the neurotransmitter GABA – is critical for the representation of the scent. These results have implications toward understanding the olfactory basis of mosquito-nectar-seeking behaviors.
Spatial control of viscoelasticity in phototunable hyaluronic acid hydrogels
Authors: Hui Erica , Gimeno Kathryn I. , Guan Grant , Caliari Steven R. 
Published: May 2019

AbstractViscoelasticity has emerged as a critical regulator of cell behavior. However, there is an unmet need to develop biomaterials where viscoelasticity can be spatiotemporally tuned to mimic the dynamic and heterogeneous nature of tissue microenvironments. Toward this objective, we developed a modular hyaluronic acid hydrogel system combining light-mediated covalent and supramolecular crosslinking to afford spatiotemporal control of network viscoelastic properties. Covalently crosslinked elastic hydrogels or viscoelastic hydrogels combining covalent and supramolecular interactions were fabricated to match healthy and fibrotic liver stiffness. LX-2 human hepatic stellate cells cultured on viscoelastic substrates displayed reduced spreading, less actin stress fiber organization, and lower myocardin-related transcription factor A (MRTF-A) nuclear localization compared to cells on elastic hydrogels. We further demonstrated the dynamic capabilities of our hydrogel system through photomediated secondary incorporation of either covalent or supramolecular crosslinks to modulate viscoelastic properties. We used photopatterning to create hydrogel models with well-controlled patterned regions of stiff elastic mechanics representing fibrotic tissue nodules surrounded by regions of soft viscoelastic hydrogel mimicking healthy tissue. Cells responded to the local mechanics of the patterned substrate with increased spreading in fibrosis-mimicking regions. Together, this work represents an important step forward toward the creation of hydrogel models with spatiotemporal control of both stiffness and viscoelastic cell-instructive cues.
An adult brain atlas reveals broad neuroanatomical changes in independently evolved populations of Mexican cavefish
Authors: Loomis Cody , Peuß Robert , Jaggard James , Wang Yongfu , McKinney Sean , Raftopoulos Stephen , Raftopoulos Austin , Whu Daniel , Green Matthew , McGaugh Suzanne E. , Rohner Nicolas , Keene Alex C. , Duboue Erik R. 
Published: May 2019

AbstractA shift in environmental conditions impacts the evolution of complex developmental and behavioral traits. The Mexican cavefish, Astyanax mexicanus, is a powerful model for examining the evolution of development, physiology, and behavior because multiple cavefish populations can be compared to an extant and ancestral-like surface population of the same species. Many behaviors have diverged in cave populations of A. mexicanus, and previous studies have shown that cavefish have a loss of sleep, reduced stress, an absence of social behaviors, and hyperphagia. Despite these findings, surprisingly little is known about the changes in neuroanatomy that underlie these behavioral phenotypes. Here, we use serial sectioning to generate a brain atlas of surface fish and three independent cavefish populations. Volumetric reconstruction of serial-sectioned brains confirms convergent evolution on reduced optic tectum volume in all cavefish populations tested. In addition, we quantified volumes of specific neuroanatomical loci within several brain regions, which have previously been implicated in behavioral regulation, including the hypothalamus, thalamus, and habenula. These analyses reveal an expansion of the hypothalamus across all three cavefish populations relative to surface fish, as well as subnuclei-specific differences within the thalamus and habenulae. Taken together, these analyses support the notion that changes in environmental conditions are accompanied by neuroanatomical changes in brain structures associated with behavior. This atlas provides a resource for comparative neuroanatomy of additional brain regions and the opportunity to associate brain anatomy with evolved changes in behavior.
A stress-induced block in dicarboxylate uptake and utilization in Salmonella
Authors: Hersch Steven J. , Radan Bojana , Ilyas Bushra , Lavoie Patrick , Navarre William Wiley 
Published: May 2019

AbstractBacteria have evolved to sense and respond to their environment by altering gene expression and metabolism to promote growth and survival. In this work we demonstrate that Salmonella displays an extensive (>30 hour) lag in growth when subcultured into media where dicarboxylates such as succinate are the sole carbon source. This growth lag is regulated in part by RpoS, the RssB anti-adaptor IraP, translation elongation factor P, and to a lesser degree the stringent response. We also show that small amounts of proline or citrate can trigger early growth in succinate media and that, at least for proline, this effect requires the multifunctional enzyme/regulator PutA. We demonstrate that activation of RpoS results in the repression of dctA, encoding the primary dicarboxylate importer, and that constitutive expression of dctA induced growth. This dicarboxylate growth lag phenotype is far more severe across multiple Salmonella isolates than in its close relative E. coli. Replacing 200 nt of the Salmonella dctA promoter region with that of E. coli was sufficient to eliminate the observed lag in growth. We hypothesize that this cis-regulatory divergence might be an adaptation to Salmonella’s virulent lifestyle where levels of phagocyte-produced succinate increase in response to bacterial LPS. We found that impairing dctA repression had no effect on Salmonella’s survival in acidified succinate or in macrophage but propose alternate hypotheses of fitness advantages acquired by repressing dicarboxylate uptake.ImportanceBacteria have evolved to sense and respond to their environment to maximize their chance of survival. By studying differences in the responses of pathogenic bacteria and closely related non-pathogens, we can gain insight into what environments they encounter inside of an infected host. Here we demonstrate that Salmonella diverges from its close relative E. coli in its response to dicarboxylates such as the metabolite succinate. We show that this is regulated by stress response proteins and ultimately can be attributed to Salmonella repressing its import of dicarboxylates. Understanding this phenomenon may reveal a novel aspect of the Salmonella virulence cycle, and our characterization of its regulation yields a number of mutant strains that can be used to further study it.