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Vision Research Nov 1998The experimental data in this paper show that chromatic bars presented in alternation with equiluminant neutral-appearing bars are seen as more saturated than the same...
The experimental data in this paper show that chromatic bars presented in alternation with equiluminant neutral-appearing bars are seen as more saturated than the same chromaticity presented as a uniform rectangle. This effect was diminished but not eliminated when test and match stimuli were presented within a slightly dimmer neutral surround. The test stimulus was a 2 x 5 degrees rectangle with a 0.7 cpd square wave grating composed of alternating equiluminant chromatic test bars and neutral bars. Asymmetric matching was used to match the test bar appearance to a uniform 2 x 5 degrees comparison rectangle. Test and comparison stimuli were presented to separate eyes in a haploscope and appeared flanking a central fixation target. Data were collected with test and inducing stimuli on the cardinal axes of color space. Test bars separated by neutral bars appeared more saturated than the comparison rectangle for both the l- and s-axis directions. Manipulation of excitation on one cardinal axis did not affect the appearance matches made for the other cardinal axis.
Topics: Adult; Color Perception; Color Perception Tests; Female; Humans; Male; Pattern Recognition, Visual; Spectrophotometry
PubMed: 9893836
DOI: 10.1016/s0042-6989(98)00027-3 -
Journal of Anatomy Jul 1999The subchondral bone plate supports the articular cartilage in diarthrodial joints. It has a significant mechanical function in transmitting loads from the cartilage... (Comparative Study)
Comparative Study
The subchondral bone plate supports the articular cartilage in diarthrodial joints. It has a significant mechanical function in transmitting loads from the cartilage into the underlying cancellous bone and has been implicated in the destruction of cartilage in osteoarthritis (OA) and its sparing in osteoporosis (OP), but little is known of its composition, structure or material properties. This study investigated the microscopic appearance and mineral composition of the subchondral bone plate in femoral heads from patients with OA or OP to determine how these correspond to changes in composition and stiffness found in other studies. Freeze-fractured full-depth samples of the subchondral bone plate from the femoral heads of patients with osteoarthritis, osteoporosis or a matched control group were examined using back scattered and secondary emission scanning electron microscopy. Other samples were embedded and polished and examined using back-scattered electron microscopy and electron probe microanalysis. The appearances of the samples from the normal and osteoporotic patients were very similar, with the subchondral bone plate overlayed by a layer of calcified cartilage. Osteoporotic samples presented a more uniform fracture surface and the relative thicknesses of the layers appeared to be different. In contrast, the OA bone plate appeared to be porous and have a much more textured surface. There were occasional sites of microtrabecular bone formation between the trabeculae of the underlying cancellous bone, which were not seen in the other groups, and more numerous osteoclast resorption pits. The calcified cartilage layer was almost absent and the bone plate was apparently thickened. The appearance of the osteoarthritic subchondral bone plate was, therefore, considerably different from both the normal and the osteoporotic, strongly indicative of abnormal cellular activity.
Topics: Aged; Bone Density; Electron Probe Microanalysis; Female; Femur Head; Freeze Fracturing; Humans; Male; Microscopy, Electron, Scanning; Osteoarthritis; Osteoporosis
PubMed: 10473297
DOI: 10.1046/j.1469-7580.1999.19510101.x -
AJNR. American Journal of Neuroradiology May 2003During the review of MR studies of multiple patients with polymicrogyria (PMG), it was noted that the patterns of cortical abnormality differed significantly among...
BACKGROUND AND PURPOSE
During the review of MR studies of multiple patients with polymicrogyria (PMG), it was noted that the patterns of cortical abnormality differed significantly among affected patients. In particular, the cortex appeared very thin in some patients, but was thick in others. The purpose of the present study was to attempt to clarify the cause of the different imaging appearances.
METHODS
T1- and T2-weighted images obtained in 17 patients (age range, 3 days to 43 years) with PMG diagnosed on the basis of imaging characteristics were retrospectively reviewed. One patient was examined four times over a period of 21 months. Particular attention was paid to the thickness and signal intensity of the cortex and underlying white matter and how these features varied with maturation of the cortex and white matter.
RESULTS
T2-weighted images revealed two patterns of PMG. Pattern 1 showed small, fine, and undulating cortex with normal thickness (3-4 mm) in seven patients, all younger than 12 months; and pattern 2, a bumpy cortex that appeared abnormally thick (6-8 mm) and had an irregular cortical-white matter junction in seven patients older than 18 months. Both patterns were observed in four patients between 15 months and 2 years of age (ie, pattern 1 in the anterior frontal region and pattern 2 in the posterior frontal, parietal, or perisylvian regions). A layer of T2 prolongation (2-3 mm) was recognized between pattern 1 PMG and underlying myelinated white matter in four patients 11 months to 2 years of age. T1-weighted images showed either poor differentiation of the cortex and underlying white matter or pattern 2. Serial MR imaging in one patient depicted longitudinal changes of the PMG from pattern 1 to pattern 2.
CONCLUSION
These findings suggest that the two appearances (thin and thick) of the cortex seen in PMG likely represent the same process, with the apparent difference being the result of myelination in subcortical and intracortical fibers that cause a change of the appearance and apparent thickness of PMG on T2-weighted images.
Topics: Adolescent; Adult; Cerebral Cortex; Child; Child, Preschool; Female; Humans; Infant; Infant, Newborn; Magnetic Resonance Imaging; Male; Myelin Sheath; Retrospective Studies
PubMed: 12748072
DOI: No ID Found -
Seminars in Nephrology Sep 2004Almost every patient with chronic renal failure (CRF) eventually develops secondary hyperparathyroidism (SH) unless they are treated with proper and novel medications in...
Almost every patient with chronic renal failure (CRF) eventually develops secondary hyperparathyroidism (SH) unless they are treated with proper and novel medications in advanced medical centers by skilled medical personnel. Every kind of bone abnormality including skull deformities has been described in detail by almost every concerned researcher and textbook, but descriptions of this phenomenon are limited in the medical literature to the years from 1973 to 1977. To our knowledge, extensive data regarding uglifying human face appearances have not been defined so far in the literature. We are therefore making this addition to the clinical nephrology field by accumulating such data. After we found 2 consecutive peculiar and unique patients with uglifying human face appearances in 2000, we attempted to inform and draw attention to this new entity to all hemodialysis (HD) centers in Turkey, as well as in other developing countries around the world to collect data on this phenomenon. Accordingly, we visited dialysis centers and patients' houses to collect detailed information, including medical clinical histories, physical examinations, laboratory data, biographies, current medications, and so forth. We found 25 patients who had CRF, SH, short stature, extremely severe skull changes, maxillary and mandibular bone changes, teeth/dental abnormalities, and soft and innocuous tumoral tissues in the mouth (hence, uglifying the appearance of the face), fingertip changes, severe psychologic problems, and depression. It appears that patients with CRF may have a new syndrome of bone deformities that have long been neglected, ignored, and forgotten since the mid-1970s when they were first described. This is vital and critical information for the clinical status of patients who suffered from the syndrome that we have named Sagliker syndrome (SS), and we believe there are many more patients in the world who are suffering from it.
Topics: Abnormalities, Multiple; Age Factors; Child; Face; Facial Bones; Female; Humans; Hyperparathyroidism, Secondary; Kidney Failure, Chronic; Male; Severity of Illness Index; Syndrome
PubMed: 15490409
DOI: 10.1016/j.semnephrol.2004.06.021 -
Radiographics : a Review Publication of... 2008Many extraocular masses involving the pediatric orbit have an osseous origin. The most common is the dermoid inclusion cyst; these cystic lesions may contain lipid and... (Review)
Review
Many extraocular masses involving the pediatric orbit have an osseous origin. The most common is the dermoid inclusion cyst; these cystic lesions may contain lipid and are most often found near the zygomaticofrontal suture, adjacent to an indolent-appearing erosion of bone. Some primary bone lesions may involve the orbit, producing a lytic or dense lesion with enlargement of the bone; these lesions include fibrous dysplasia, juvenile ossifying fibroma, and osteosarcoma. Fibrous dysplasia tends to produce a mass of ground-glass appearance with longitudinal osseous expansion, whereas juvenile ossifying fibroma is likely to produce a mixed lytic and sclerotic lesion and focal osseous enlargement. Osteosarcoma causes marked bone destruction and variable osteoid production. Langerhans cell histiocytosis, an idiopathic reticuloendothelial proliferative disorder, tends to involve the bones of the skull, especially the lateral orbital roof; it produces lytic destruction of bone with a sclerotic rim and a large intraorbital soft-tissue mass. Granulocytic sarcoma is a solid tumor that may occur in children with myelogenous leukemia. These tumors tend to arise in the subperiosteum of the lateral orbital wall, although they usually do not disrupt the bone. Finally, the orbit is a common site for bone metastases from neuroblastoma, which cause aggressive periosteal reaction in the orbital roof or lateral wall. The last three conditions are often bilateral. At imaging evaluation, osseous lesions may appear similar to each other and to nonosseous masses of the orbit. Knowledge of the pathologic features of these tumors and how these features are reflected in their imaging appearances may help radiologists differentiate them.
Topics: Child; Humans; Orbital Neoplasms; Tomography, X-Ray Computed
PubMed: 18635637
DOI: 10.1148/rg.284085013 -
Oecologia May 2008Data on the first appearance of species in the field season are widely used in phenological studies. However, there are probabilistic arguments for bias in estimates of...
Data on the first appearance of species in the field season are widely used in phenological studies. However, there are probabilistic arguments for bias in estimates of phenological change if sampling methods or population abundances change. We examined the importance of bias in three measures of phenological change: (1) the date of the first X appearances, (2) the date of the first Y% of all first appearances and (3) the date of the first Z% of the individuals observed during the entire flight period. These measures were tested by resampling the data of the Dutch Butterfly Monitoring Scheme and by simulations using artificial data. We compared datasets differing in the number of sampling sites, population abundance and the start of the observation period. The date of the first X appearances proved to be sensitive to the number of sampling sites. Both the date of the first X appearances and the date of the first Y% of all first appearances were sensitive to population trend. No such biases were found for estimates of the first Z% of the flight period, but all three measures were sensitive to changes in the start of the observation period. The conclusions were similar for both the study on butterfly data and the simulation study. Bias in phenology assessments based on first appearance data may be considerable and should no longer be ignored in phenological research.
Topics: Animals; Bias; Butterflies; Computer Simulation; Ecology; Monte Carlo Method; Population Density
PubMed: 18236084
DOI: 10.1007/s00442-008-0959-4 -
Arquivos de Neuro-psiquiatria Jun 1998Dystonia is a rare consequence of head trauma. We describe one case of post-traumatic spasmodic torticollis and review thirty-one cases reported in the literature. The... (Review)
Review
Dystonia is a rare consequence of head trauma. We describe one case of post-traumatic spasmodic torticollis and review thirty-one cases reported in the literature. The time course among the head injury and the onset of dystonia ranged from two hours to nine years. Eleven cases had mild head injury and twenty had severe. On CT studies, the most frequent lesion was extradural, subdural and thalamic hemorrhagies; on MRI there were lesions in contralateral basal ganglia or thalamus. In our case, initial CT findings were bilateral hygroma and generalized brain edema. A follow-up CT sixt days after head injury showed cerebral atrophy and MRI scan (one year later) showed cerebral atrophy either. The pathophysiologic mechanisms related to the appearence of dystonia are poorly understood. However, there are evidences suggesting that some dysfunction of lenticulothalamic neuronal circuits plays an important role. The period of time between the head injury and the appearance of post-traumatic dystonia, seems to be related to aberrant central neurons.
Topics: Adolescent; Adult; Brain Injuries; Child; Child, Preschool; Dystonia; Female; Humans; Male; Middle Aged; Spasm; Torticollis
PubMed: 9698745
DOI: 10.1590/s0004-282x1998000200023 -
Acta Neurologica Scandinavica May 2021Minor hallucinations (MHs), including sense of presence, passage hallucinations, and visual illusions, have been reported in Parkinson's disease (PD). Here, we...
OBJECTIVES
Minor hallucinations (MHs), including sense of presence, passage hallucinations, and visual illusions, have been reported in Parkinson's disease (PD). Here, we investigated the prevalence and associated risk factors for MHs according to appearance time.
METHODS
Data on the clinical characteristics and the appearance time of MHs for 100 PD patients were collected using a questionnaire and analyzed. MHs were classified into two groups according to the time when MHs appeared: MHs appearing while awake during the daytime (dMHs) and MHs appearing at arousal from sleep during the night or early morning (aMHs).
RESULTS
Thirty-eight patients (38%) experienced MHs. dMHs and aMHs were present in 21 (21%) and 28 patients (28%), respectively. Compared to patients without MHs, patients with dMHs had more severe motor symptoms, longer disease duration, higher levodopa equivalent daily dose (LEDD), and higher rates of cognitive impairment and visual hallucinations during the daytime, whereas patients with aMHs had a higher rate of rapid eye movement sleep behavior disorder (RBD), longer disease duration, higher LEDD, and higher dopamine agonist dosage. Logistic regression analysis showed that cognitive impairment was significantly associated with dMHs (odds ratio (OR) 7.292, p = .001), and that RBD (OR 8.306, p < .001) and LEDD (OR 1.002, p = .049) were significantly associated with aMHs.
CONCLUSIONS
Patients with MHs have different clinical characteristics according to the time when MHs appear. These findings have important clinical and prognostic implications and suggest appropriate therapeutic options for psychotic symptoms.
Topics: Aged; Female; Hallucinations; Humans; Male; Middle Aged; Parkinson Disease; Prevalence; Risk Factors
PubMed: 33222164
DOI: 10.1111/ane.13380 -
IEEE Transactions on Pattern Analysis... Jan 2021Multiple Object Tracking (MOT) plays an important role in solving many fundamental problems in video analysis and computer vision. Most MOT methods employ two steps:...
Multiple Object Tracking (MOT) plays an important role in solving many fundamental problems in video analysis and computer vision. Most MOT methods employ two steps: Object Detection and Data Association. The first step detects objects of interest in every frame of a video, and the second establishes correspondence between the detected objects in different frames to obtain their tracks. Object detection has made tremendous progress in the last few years due to deep learning. However, data association for tracking still relies on hand crafted constraints such as appearance, motion, spatial proximity, grouping etc. to compute affinities between the objects in different frames. In this paper, we harness the power of deep learning for data association in tracking by jointly modeling object appearances and their affinities between different frames in an end-to-end fashion. The proposed Deep Affinity Network (DAN) learns compact, yet comprehensive features of pre-detected objects at several levels of abstraction, and performs exhaustive pairing permutations of those features in any two frames to infer object affinities. DAN also accounts for multiple objects appearing and disappearing between video frames. We exploit the resulting efficient affinity computations to associate objects in the current frame deep into the previous frames for reliable on-line tracking. Our technique is evaluated on popular multiple object tracking challenges MOT15, MOT17 and UA-DETRAC. Comprehensive benchmarking under twelve evaluation metrics demonstrates that our approach is among the best performing techniques on the leader board for these challenges. The open source implementation of our work is available at https://github.com/shijieS/SST.git.
PubMed: 31329110
DOI: 10.1109/TPAMI.2019.2929520 -
AJR. American Journal of Roentgenology Nov 2004We sought to investigate the efficacy of contrast-enhanced sonography using a second-generation contrast agent for the evaluation of hepatocellular carcinoma in patients... (Comparative Study)
Comparative Study
OBJECTIVE
We sought to investigate the efficacy of contrast-enhanced sonography using a second-generation contrast agent for the evaluation of hepatocellular carcinoma in patients with cirrhosis by comparing the results to those obtained with contrast-enhanced helical CT.
SUBJECTS AND METHODS
Between October 2002 and March 2003, 74 patients with cirrhosis (60 men and 14 women; age range, 47-80 years; mean age, 67 years) who had a single nodule of hepatocellular carcinoma were selected to be studied from a cohort of 437 patients with cirrhosis. The size range of the 74 nodules was 9-65 mm (mean, 28.2 mm). Twenty-eight (38%) were 20 mm smaller (range, 9-20 mm; mean, 16.6 mm), and 46 (62%) were larger than 20 mm (range, 21-65 mm; mean, 35.2 mm). Contrast-enhanced sonography was performed at a low mechanical index after IV administration of the contrast agent SonoVue. CT scans were obtained in all patients. The enhancement pattern related to tumor hypervascularity was analyzed. The chi-square test was used for statistical analysis.
RESULTS
For the 28 hepatocellular carcinomas 20 mm or smaller, contrast-enhanced sonography showed 15 (53.6%) as hypervascular and 10 (35.7%) as avascular; three (10.7%) carcinomas were missed. On CT, 12 (42.9%) of the 28 hepatocellular carcinomas appeared hypervascular, 13 (46.4%) appeared hypovascular, and three (10.7%) were missed. For the 46 hepatocellular carcinomas larger than 20 mm, contrast-enhanced sonography showed 42 (91.3%) as hypervascular and four (8.7%) as avascular. On CT, 35 (76.1%) hepatocellular carcinomas appeared hypervascular, eight (17.4%) appeared hypovascular, and three (6.5%) were missed. Differences between CT appearance of hepatocellular carcinomas and contrast-enhanced sonographic appearance of the carcinomas were not statistically significant. Concordance between contrast-enhanced sonographic and CT appearances was observed in 61 (82.4%) of 74 cases.
CONCLUSION
Contrast-enhanced sonography is similar to CT for detecting hepatocellular carcinoma hypervascularity. It could be complementary to conventional unenhanced sonography for evaluation of liver nodules.
Topics: Aged; Aged, 80 and over; Carcinoma, Hepatocellular; Contrast Media; Female; Humans; Liver Cirrhosis; Liver Neoplasms; Male; Middle Aged; Phospholipids; Sulfur Hexafluoride; Tomography, Spiral Computed; Ultrasonography
PubMed: 15505297
DOI: 10.2214/ajr.183.5.1831319