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1.
AJNR Am J Neuroradiol ; 44(1): 11-16, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36521960

RESUMO

BACKGROUND AND PURPOSE: Protocolling, the process of determining the most appropriate acquisition parameters for an imaging study, is time-consuming and produces variable results depending on the performing physician. The purpose of this study was to assess the potential of an artificial intelligence-based semiautomated tool in reducing the workload and decreasing unwarranted variation in the protocolling process. MATERIALS AND METHODS: We collected 19,721 MR imaging brain examinations at a large academic medical center. Criterion standard labels were created using physician consensus. A model based on the Long Short-Term Memory network was trained to predict the most appropriate protocol for any imaging request. The model was modified into a clinical decision support tool in which high-confidence predictions, determined by the values the model assigns to each possible choice, produced the best protocol automatically and low confidence predictions provided a shortened list of protocol choices for review. RESULTS: The model achieved 90.5% accuracy in predicting the criterion standard labels and demonstrated higher agreement than the original protocol assignments, which achieved 85.9% accuracy (κ = 0.84 versus 0.72, P value < .001). As a clinical decision support tool, the model automatically assigned 70% of protocols with 97.3% accuracy and, for the remaining 30% of examinations, achieved 94.7% accuracy when providing the top 2 protocols. CONCLUSIONS: Our model achieved high accuracy on a standard based on physician consensus. It showed promise as a clinical decision support tool to reduce the workload by automating the protocolling of a sizeable portion of examinations while maintaining high accuracy for the remaining examinations.


Assuntos
Inteligência Artificial , Sistemas de Apoio a Decisões Clínicas , Humanos , Imageamento por Ressonância Magnética/métodos , Neuroimagem , Encéfalo/diagnóstico por imagem
2.
J Phys Chem B ; 122(29): 7319-7331, 2018 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-29912560

RESUMO

Neural stimulation has widespread applications in investigating brain functions, restoring impaired neural functions, and treating numerous neurological/psychiatric diseases. Use of infrared pulses to stimulate neurons (infrared neural stimulation) offers a direct and non-invasive technique. Recent research has demonstrated that transient heating associated with the absorption of infrared light by the local aqueous medium around the cell membrane can stimulate nerves. One mechanism for this stimulation is due to a thermally induced increase in the membrane electrical capacitance, which causes cell depolarization as well as action potential production under certain physiological conditions. A theoretical and computational model helps better understand the mechanism of thermally induced electrical capacitance changes and optimize the stimulus parameters. In this article, we develop the existing theoretical models for membrane electrical capacitance and its thermally induced changes. We improve the formulation of Gouy-Chapman-Stern theory by Genet et al. and Shapiro et al. with the addition of a diffuse layer to the electrical double layer and by modifying the relation of Stern layer capacitance, to calculate the membrane capacitive charge and capacitive current. We also present a new method to calculate the membrane electrical capacitance and the rate of its thermally induced changes. In our calculations, two new factors are considered including the temperature dependence of the surface charge density and the hydrophobic core dielectric constant of the lipid bilayer. Our developed model predicts rates of 0.3 and 0.26%/°C for the thermally induced capacitance changes of the artificial lipid bilayer under two different sets of conditions previously reported by Shapiro et al. and Carvalho-de-Souza et al., respectively. Our model is in very good agreement with the corresponding experimental values given by these groups. The presented model is also able to calculate the membrane capacitive currents and investigate the voltage dependence of this current.


Assuntos
Lasers , Bicamadas Lipídicas/química , Modelos Teóricos , Capacitância Elétrica , Bicamadas Lipídicas/efeitos da radiação , Potenciais da Membrana , Temperatura
4.
Biol Reprod ; 96(3): 635-651, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28339602

RESUMO

Neuroendocrine regulation of metabolism and reproduction are tightly interlinked. Nesfatin-1 is an 82 amino acid metabolic peptide derived from nucleobindin-2 (NUCB2). NUCB2 mRNA and protein significantly increase in the hypothalamus of rats during puberty-to-adult transition. Administration of nesfatin-1 modulates circulating LH and testosterone in male rats. However, whether nesfatin-1 acts directly on neurons and gonadotropes remain unknown. In addition, whether reproductive hormones of the hypothalamo-pituitary gonadal axis modulate NUCB2/nesfatin-1 is unclear. To address these, we employed murine hypothalamic (GT1-7) and pituitary (LßT2) cells in vitro. Nucb2 expression, and NUCB2/nesfatin-1 immunoreactivity were observed in both GT1-7 and LßT2 cells, and in the hypothalamus of mice. Nesfatin-1 co-localized GnRH in GT1-7 cells, and in the hypothalamic perikarya of mice. Cells were treated with kisspeptin, GnRH, and estradiol and testosterone, as well as nesfatin-1 for 2, 6 or 24 hours. Synthetic nesfatin-1 increased Kiss1r and Gnrh expression in GT1-7 cells and Lhß in LßT2. Nesfatin-1 increased GnRH and LHß protein expression in GT1-7 and LßT2 at 6-hour post incubation respectively. Both NUCB2 mRNA and protein were increased in GT1-7 cells treated with kisspeptin. Testosterone increased NUCB2 mRNA and protein expression in GT1-7 and LßT2. 17ß-estradiol increased NUCB2 mRNA and protein expression in LßT2. Nesfatin-1 acts directly on hypothalamic neurons and gonadotropes to elicit a generally positive influence on the endocrine milieu regulating reproduction in mice. Reproductive hormones, in turn, modulate brain and pituitary NUCB2/nesfatin-1. In conclusion, we provide additional information to designate nesfatin-1 as a novel, additional factor that helps reproductive success.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ligação a DNA/metabolismo , Gonadotrofos/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Receptores de Kisspeptina-1/metabolismo , Animais , Linhagem Celular , Estradiol , Receptor alfa de Estrogênio/metabolismo , Kisspeptinas , Camundongos , Nucleobindinas , Testosterona
5.
Nanotechnology ; 24(20): 205201, 2013 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-23609222

RESUMO

Interaction of a hybrid system consisting of a semiconductor quantum dot and a metallic nanoparticle (MNP) with a laser beam can replace the intrinsic plasmonic field of the MNP with a coherently normalized field (coherent-plasmonic or CP field). In this paper we show how quantum coherence effects in such a hybrid system can form a coherent barrier (quantum cage) that spatially confines the CP field. This allows us to coherently control the modal volume of this field, making it significantly smaller or larger than that of the intrinsic plasmonic field of the MNP. We investigate the spatial profiles of the CP field and discuss how the field barrier depends on the collective states of the hybrid system.

6.
Theriogenology ; 74(2): 317-25, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20416931

RESUMO

In Vimba vimba, GSI, sperm volume, and spermatozoa concentration range from 3.4-7.4 %, 0.1-1.1 ml, and 13.3-34.8 x 10(9) spz ml(-1), respectively. Gonad mass (r = 0.90) and sperm volume (r = 0.35) significantly correlated with weight of males. Significant correlation was also found between gonad mass and length of males (r = 0.85). Sperm motility (r = 0.99) and velocity (r = 098) significantly decreased after activation in Tris-HCl 20 mM, pH 8.5. Osmolality of the seminal plasma was 273.2 mOsmol kg(-1). Sperm motility and velocity were significantly affected by the osmolality of the activation medium (P < 0.01). Hyper-osmolality compared to seminal plasma osmolality totally suppressed the sperm activation. At 15 s post-activation, the sperm motility significantly decreased at 240 mOsmol kg(-1) in KCl or NaCl media. The highest sperm motility and velocity (at 60 s post-activation) were observed at 200 mOsmol kg(-1) in NaCl, KCl, or sucrose media. In all treatments, the tip of the flagellum of spermatozoa became curled into a loop shape after activation of sperm in distilled water containing 20 mM Tris-HCl, pH 8.5 that shortened the flagellum.


Assuntos
Cyprinidae/fisiologia , Reprodução , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/fisiologia , Animais , Tamanho Corporal , Técnicas de Cultura de Células , Meios de Cultura , Cyprinidae/anatomia & histologia , Masculino , Concentração Osmolar , Cloreto de Potássio/farmacologia , Sêmen/efeitos dos fármacos , Comportamento Sexual Animal , Cloreto de Sódio/farmacologia , Espermatozoides/citologia , Espermatozoides/efeitos dos fármacos
7.
Anim Reprod Sci ; 100(3-4): 356-63, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16987621

RESUMO

In order to study the effects of storage media and time of storage on the viability of unfertilized eggs of endangered Caspian brown trout (Salmo trutta caspius), the ova of this fish was stored in coelomic fluid and Cortland artificial media at 2-3 degrees C for 120 h. In this research, Cortland artificial medium was buffered with 20 mM of three different buffers: Hepes (C(8)H(18)N(2)O(4)S), Tris-HCl (C(4)H(11)NO(3)-HCl) and sodium salt Hepes (C(8)H(17)N(2)O(4)SNa). The pH of these media were adjusted according to natural pH of coelomic fluid. The eggs that stored in these media fertilized at times 0 h (eggs fertilized prior to storage), 48, 72 and 120 h of post-stripping, using fresh and pooled sperm obtained from four to six males. According to the results of present study, time of storage showed a significant (p<0.05) main effect on eyeing, hatching and eyed eggs mortality rates. Eyeing and hatching rates significantly (p<0.05) decreased from 97.4+/-2.1% and 95.1+/-4.4% at time 0 (eggs fertilized prior to storage) to 77.9+/-3% and 65.5+/-5% after 120 h of storage. Within a similar period of time, eyed eggs mortality significantly (p<0.05) increased from 2.4+/-2.4% to 17.2+/-3.9%. No significant (p>0.05) main effect was found among media buffered with Tris-HCl (82.8+/-3.2%, 73.4+/-5.4%, 12.1+/-4.5%), Hepes (88.2+/-3.4%, 80.7+/-5.5%, 9.3+/-3.4%), sodium salt Hepes (77.8+/-3.8%, 69.3+/-5.7%, 12.2+/-3.9%) and coelomic fluid (84.8+/-3.8%, 77.7+/-5.1%, 8.9+/-2.7%) for eyeing, hatching and eyed eggs mortality rates. There was a negative correlation (r=-0.895, p<0.001) between eyed eggs mortality and hatching rates. In conclusion, unfertilized eggs of endangered Caspian brown trout can be successfully stored for 48 h without significant loss of fertility. But, storage for 120 h results in the falling of hatching rate. In addition, no significant difference was found between viability rates of ova stored in coelomic fluid and artificial media, 120 h post-storage. It reveals that artificial media could be substituted for coelomic fluid as storage medium at least for 120 h in Caspian brown trout.


Assuntos
Óvulo/fisiologia , Preservação Biológica , Truta/fisiologia , Animais , Meios de Cultura , Feminino , Fertilidade , Concentração de Íons de Hidrogênio , Fatores de Tempo
8.
Cancer ; 51(4): 618-22, 1983 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-6681593

RESUMO

A first case of angiosarcoma of the vagina is described. Review of medical literature fails to show any documented cases of primary angiosarcoma of the vagina. Because of its rarity, no definite treatment could be suggested. The guideline for the management of this disease can only be drawn from several previously reported angiosarcomas of the uterus, cervix, and pelvis. It is recommended that a combined form of external irradiation and intracavitary brachytherapy be used after removal of the tumor.


Assuntos
Hemangiossarcoma/patologia , Neoplasias Vaginais/patologia , Braquiterapia , Feminino , Hemangiossarcoma/radioterapia , Hemangiossarcoma/cirurgia , Humanos , Pessoa de Meia-Idade , Neoplasias Pélvicas/radioterapia , Neoplasias do Colo do Útero/radioterapia , Neoplasias Uterinas/radioterapia , Neoplasias Vaginais/radioterapia , Neoplasias Vaginais/cirurgia
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