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At least 487 records · Page 27Linked to original sources
PubMed2026

A Foundation Model Based CT Biomarker for Non-Invasive Prediction of Response to Neoadjuvant Immunochemotherapy in Non-Small Cell Lung Cancer.

Predicting pathological complete response (pCR) to neoadjuvant immunochemotherapy in non-small cell lung cancer (NSCLC) is clinically important yet remains challenging. Here, we introduce a foundation model-derived computed tomography (CT) imaging biomarker established from a multi-center cohort of 702 patients. Specifically, we developed and validated a non-invasive baseline CT-based model for risk stratification of pathological response. To address scanner and protocol heterogeneity, we first built a 3D Vision Mamba-based CT super-resolution model trained on 2494 cases for image standardization. We then fine-tuned a lung cancer-specific CT foundation model from a pretrained 3D model (VoCo) using 6643 chest CT scans. Finally, we constructed a multi-task Swin Transformer that jointly performs risk stratification and segments tumors to generate the imaging biomarker. Across five centers, the model achieved consistently strong generalization (AUC: 0.75-0.87) for pCR prediction. Genomic analysis revealed that the biomarker was independent of tumor mutational burden but significantly associated with TP53 mutations, suggesting an association with a radiogenomic phenotype related to this alteration. Together, these results demonstrate a generalizable and biologically meaningful foundation model-based biomarker for non-invasive risk stratification of pathological response in NSCLC.

Female↗
PubMed1982

Multiplication noise in the human visual system at threshold: 2. Probit estimation of parameters.

A mathematical technique is described that relates detection model parameters to stimulus magnitude and experimental probability of detection. The normalizing transform is used to make the response statistics approximately Gaussian. Conventional probit analysis is then applied. From measurements at M stimulus levels, a system of M equations is solved and estimates of M unknown parameters of the detection model are obtained. The technique is applied to a threshold vision model based on additive and multiplicative Poisson noise. Results are obtained for the parameter estimates for individual subjects, and for the standard deviation of the estimates, for various values of the stimulus energy and number of trials. A frequency-of-seeing experiment is performed using a point-source stimulus that randomly assumes 3 energy levels with 200 trials per level. With a central efficiency of 50%, the estimated ocular quantum efficiency for our four subjects lies between 12% and 23%, the average dark count at the retina lies between 8 and 36 counts, and the threshold count for our (low false-report rate) data lies between 11 and 32. The theoretical results reduce to those obtained by Barlow (J. Physiol. London 160, 155-168, 1962), in the absence of dark light and multiplication noise.

Humans↗
PubMedDate not supplied

Sensory coding, decoding, and representations. Unnecessary and troublesome constructs?

Reception of certain environmental energy patterns can allow organisms to successfully respond to present or future environmental conditions. Sensory systems are the means by which this reception occurs. The bioelectric components of this process are typically characterized as "sensory coding." "Coding" logically requires subsequent "decoding," and implies that the decoder has a special, commanding role. In contrast, the term "transformation," which is sometimes applied to the prebioelectric components of sensory systems, can connote a series of changes in the medium, form, or content of sensory processes. Neither coding nor decoding are implied, no notions of "representation" or "reconstruction" of the world are introduced, and distributed, parallel processing is a natural corollary of transformations. It is proposed that the problematic construct of sensory coding, with its concomitant decoding, be replaced with the more neutral and physical concept of transformations. Elimination of the notions of representation or reconstruction of the world in some special nervous system locus is also suggested.

Animals↗
PubMed1998

An efficient motion estimator with application to medical image registration.

Image registration is a very important problem in computer vision and medical image processing. Numerous algorithms for registering single and multi-modal image data have been reported in these areas. Robustness as well as computational efficiency are prime factors of importance in image data registration. In this paper, a robust/reliable and efficient algorithm for estimating the transformation between two image data sets of a patient taken from the same modality over time is presented. Estimating the registration between two image data sets is formulated as a motion-estimation problem. We use a hierarchical optical flow motion model which allows for both global as well as local motion between the data sets. In this hierarchical motion model, we represent the flow field with a B-spline basis which implicitly incorporates smoothness constraints on the field. In computing the motion, we minimize the expectation of the squared differences energy function numerically via a modified Newton iteration scheme. The main idea in the modified Newton method is that we precompute the Hessian of the energy function at the optimum without explicitly knowing the optimum. This idea is used for both global and local motion estimation in the hierarchical motion model. We present examples of motion estimation on synthetic and real data (from a patient acquired during pre- and post-operative stages) and compare the performance of our algorithm with that of competing ones.

Algorithms↗
PubMed2006

Monocular cells without ocular dominance columns.

In many regions of the mammalian cerebral cortex, cells that share a common receptive field property are grouped into columns. Despite intensive study, the function of the cortical column remains unknown. In the squirrel monkey, the expression of ocular dominance columns is variable, with columns present in some animals and not in others. By searching for differences between animals with and without columns, it should be possible to infer how columns contribute to visual processing. Single-cell recordings outside layer 4C were made in nine squirrel monkeys, followed by labeling of ocular dominance columns in layer 4C. In the squirrel monkey, compared with the macaque, cells outside layer 4C were more likely to respond to stimulation of either eye whether ocular dominance columns were present or not. In three animals lacking ocular dominance columns, single cells were recorded from layer 4C. Remarkably, 20% of cells in layer 4C were monocular despite the absence of columns. This observation means that ocular dominance columns are not necessary for monocular cells to occur in striate cortex. In macaques each row of cytochrome oxidase (CO) patches is aligned with an ocular dominance column and receives koniocellular input serving one eye only. In squirrel monkeys this was not true: CO patches and ocular dominance columns had no spatial correlation and the koniocellular input to CO patches was binocular. Thus even when ocular dominance columns occur in the squirrel monkey, they do not transform the functional architecture to resemble that of the macaque.

Animals↗
PubMed2006

Solution focused teaching: a transformative approach to teaching nursing.

Nurses work in complex health care systems, which today are based not only on medical treatment and cure, but also on enabling individuals and strengthening communities. This paper describes a curriculum approach to teaching nursing in an Australian university which seeks to prepare students for this environment. Underpinned by transformative education principles, and termed Solution Focused Nursing, specific teaching and learning strategies are discussed. A goal is to cultivate critical thinkers and knowledge workers, that is, nurses who are not only able to work skillfully, strategically, and respectfully with clients, but who also demonstrate discernment, optimism, and vision about nursing and health care.

Australia↗
PubMed1993

Counterexample to the hypothesis of functional similarity between tactile and visual pattern perception.

In earlier work, the author has demonstrated that tactile pattern perception and visual pattern perception exhibit many parallels when the effective spatial resolution of vision is reduced to that of touch, thus supporting the hypothesis that the two pattern senses are functionally similar when matched in spatial bandwidth. The present experiments demonstrate a clear counterexample to this hypothesis of functional similarity. Specifically, it was found that the lateral masking effect of a surround on tactile character recognition increases when the surround changes in composition from solid lines to dots, whereas for vision, recognition performance goes in the opposite direction. This finding necessitates some modification of the model of character recognition proposed by the author (Loomis, 1990) as it applies to the sensing of raised tactile patterns. One possible modification would be to incorporate, as the initial stage of pattern transformation, the continuum mechanics model for the skin that was developed by Phillips and Johnson (1981b).

Adult↗
PubMed2005

[From the sociological factor to the genetic factor. Genes and disease in the pages of El País (1976-2002)].

Transformations in the Spanish public discourse on the link between genes and disease are analysed by an attentive reading of the journalistic texts published in El País between 1976 and 2002, and the newspaper's model of popularisation is explored. Whereas in the seventies a social and complex vision of disease was favoured, by the nineties the genetic approach was predominant. El País supported this "geneticisation" and forested an increasingly neutral and apolitical image of science.

Disease↗
PubMed1996

Isolation and characterization of a unique natural killer cell inhibitory factor present in the anterior chamber of the eye.

The eye is a classic example of an immunologically privileged organ. Immune privilege in the anterior chamber is a multifaceted phenomenon that may have evolved to protect delicate ocular tissues from immune-mediated damage. The anterior chamber of the eye is lined with corneal endothelial cells, which are terminally differentiated cells that are incapable of regeneration. Since corneal endothelial cells are crucial for maintaining corneal clarity, damage to these cells leads to impairment of vision and, in some cases, blindness. The absence of constitutive expression of MHC class I molecules on corneal endothelial cells makes them potential targets for NK cell-mediated cytolysis. The aqueous humor (AH) that fills the anterior chamber of the eye and bathes the corneal endothelial surface contains numerous immunomodulatory molecules, such as TGF-beta, which may protect the corneal endothelium from NK cell-mediated damage. Functionally significant levels of TGF-beta are present in AH. In this study, we demonstrate that AH inhibits NK cell-mediated cytotoxicity in vitro, but does not affect cytotoxic T lymphocyte-mediated lysis. The inhibitory effect was immediate and occurred without preincubation of NK cells with aqueous humor. The inhibitory factor could not be neutralized by Abs to TGF-beta, but was abrogated by treating AH with proteases. Inhibition was not simply due to lysis of NK cells, since AH did not alter NK cell viability. Initial purification using gel filtration chromatography showed that the activity was restricted to a single elution peak. Analysis of the active fractions by gel electrophoresis indicated that the inhibitory factor was a single protein of approximately 10 kilodaltons. The NK inhibitory factor might be an important modulator for protecting the corneal endothelium from unbridled NK cell-mediated injury and, thus, might be instrumental in preserving vision.

Animals↗
PubMed1998

Pagetic sarcoma of the calvarium: report of two cases.

Two cases of calvarium sarcoma with intracranial extension, consecutive to Paget disease of the skull are presented. The neurosurgical implications of this rare complication of a common disease are reviewed. In both cases, the symptoms of malignant degeneration were unspecific and blurred by the presence of a well-known Paget disease. Increasing headaches, focal neurological deficits and signs of intracranial hypertension were observed. Skull X-rays and Computerised Tomography did not allow to make the difference between Pagetic bone and sarcoma. In the second case, Magnetic Resonance Imaging was the most accurate in determining the precise localisation of the tumour, and the subdural invasion. Extensive surgical resection was carried out, by craniectomy of the tumoural bone, followed by cranioplasty. Dural sinus involvement and tumour hypervascularisation caused important peroperative blood loss in both patients. In the second case, the tumour invaded the subdural space through a Pacchioni granulation. Survival of patients with Pagetic sarcoma seems shorter when compared to post-radiation or primitive osteosarcoma, despite adjuvant therapies, probably because of late diagnosis and incomplete surgical resection. The mean reported survival rate is 6 months. Although the first patient died within 4 months, in the second case, the authors obtained a more than two year survival with aggressive surgery alone. These cases also illustrate the polymorphism of sarcomatous degeneration of Pagetic calvarium, the interest of MRI, and the need for close surveillance of patients with known Pagets disease of the skull.

Aged↗
PubMedDate not supplied

Building transformational partnerships in nursing.

Over the past decade, the nursing education and delivery system has moved to respond to the crisis in nursing workforce and to prepare itself for what promises to be a long and, at times, challenging struggle. Although much progress has been made, it is increasingly apparent that there are limits to what might be gained from primarily unilateral efforts. Already, issues such as scope of vision, resource constraints, and sustainability are beginning to crop up from even the best of the institutionally based efforts. What is becoming apparent to many leaders in organizations attempting to address these issues is that they cannot go it alone. They must develop partnerships with others in the education-care continuum to have any real hope of mounting and sustaining an effort to build the programs needed to address the long-term challenges of a nursing workforce that is adequate in number and skill. As this realization comes to consciousness, these leaders are becoming more aware of the need for partnerships as the foundation for a different type of strategic response. In taking the early steps toward a partnership, leaders are becoming sensitive to the different demands that a true partnership places on them and their colleagues. These demands may be periodically daunting, but they point to a set of outcomes that may actually have greater consequences for the public and patients. This article is about the creation, care, and feeding of these partnerships.

Clinical Competence↗
PubMed2005

Edge and corner detection by photometric quasi-invariants.

Feature detection is used in many computer vision applications such as image segmentation, object recognition, and image retrieval. For these applications, robustness with respect to shadows, shading, and specularities is desired. Features based on derivatives of photometric invariants, which we will call full invariants, provide the desired robustness. However, because computation of photometric invariants involves nonlinear transformations, these features are Instable and, therefore, impractical for many applications. We propose a new class of derivatives which we refer to as quasi-invariants. These quasi-invariants are derivatives which share with full photometric invariants the property that they are insensitive for certain photometric edges, such as shadows or specular edges, but without the inherent instabilities of full photometric invariants. Experiments show that the quasi-invariant derivatives are less sensitive to noise and introduce less edge displacement than full invariant derivatives. Moreover, quasi-invariants significantly outperform the full invariant derivatives in terms of discriminative power.

Algorithms↗
PubMed2006

Proprioceptive guidance of saccades in eye-hand coordination.

The saccade generator updates memorized target representations for saccades during eye and head movements. Here, we tested if proprioceptive feedback from the arm can also update handheld object locations for saccades, and what intrinsic coordinate system(s) is used in this transformation. We measured radial saccades beginning from a central light-emitting diode to 16 target locations arranged peripherally in eight directions and two eccentricities on a horizontal plane in front of subjects. Target locations were either indicated 1) by a visual flash, 2) by the subject actively moving the handheld central target to a peripheral location, 3) by the experimenter passively moving the subject's hand, or 4) through a combination of the above proprioceptive and visual stimuli. Saccade direction was relatively accurate, but subjects showed task-dependent systematic overshoots and variable errors in radial amplitude. Visually guided saccades showed the smallest overshoot, followed by saccades guided by both vision and proprioception, whereas proprioceptively guided saccades showed the largest overshoot. In most tasks, the overall distribution of saccade endpoints was shifted and expanded in a gaze- or head-centered cardinal coordinate system. However, the active proprioception task produced a tilted pattern of errors, apparently weighted toward a limb-centered coordinate system. This suggests the saccade generator receives an efference copy of the arm movement command but fails to compensate for the arm's inertia-related directional anisotropy. Thus the saccade system is able to transform hand-centered somatosensory signals into oculomotor coordinates and combine somatosensory signals with visual inputs, but it seems to have a poorly calibrated internal model of limb properties.

Adult↗
PubMed1984

Maximizing rigidity: the incremental recovery of 3-D structure from rigid and nonrigid motion.

The human visual system can extract 3-D shape information of unfamiliar moving objects from their projected transformations. Computational studies of this capacity have established that 3-D shape can be extracted correctly from a brief presentation, provided the moving objects are rigid. The human visual system requires a longer temporal extension, but it can cope with considerable deviations from rigidity. It is shown how the 3-D structure of rigid as well as nonrigid objects can be recovered by maintaining an internal model of the viewed object and modifying it at each instant by the minimal nonrigid change that is sufficient to account for the observed transformation. The results of applying this incremental rigidity scheme to rigid and nonrigid objects in motion are described and compared with human perception.

Computers↗
PubMed1993

How is depth perception affected by long-term wearing of left-right reversing spectacles?

The plasticity of binocular depth perception was investigated. Six subjects wore left-right reversing spectacles continuously for 10 or 11 days. On looking through the spectacles, the relation between the direction of physical depth (convex or concave) and the direction of binocular disparity (crossed or uncrossed) was reversed, but other depth cues did not change. When subjects observed stereograms through a haploscope and were asked to judge the direction of perceived depth, the directional relation between perceived depth and disparity was reversed both in the two line-contoured stereograms and in the random-dot stereogram in the middle of the wearing period, but the normal relation often returned late in the wearing period. When subjects observed two objects while wearing the spectacles and were asked which appeared the nearer, veridical depth perception increased as the wearing-time passed. These results indicate that the visual transformation reversing the direction of binocular disparity causes changes both in binocular stereopsis and in processes integrating different depth cues.

Depth Perception↗
PubMed1992

Visual and nonvisual information disambiguate surfaces specified by motion parallax.

Motion parallax has been shown to be an effective and unambiguous source of information about the structure of three-dimensional (3-D) surfaces, both when an observer makes lateral movements with respect to a stationary surface and when the surface translates with respect to a stationary observer (Rogers & Graham, 1979). When the same pattern of relative motions among parts of the simulated surface is presented to a stationary observer on an unmoving monitor, the perceived corrugations are unstable with respect to the direction of the peaks and troughs. The lack of ambiguity in the original demonstrations could be due to the presence of (1) non-visual information (proprioceptive and vestibular signals) produced when the observer moves or tracks a moving surface, and/or (2) additional optic flow information available in the whole array. To distinguish between these two possibilities, we measured perceived ambiguity in simulated 3-D surfaces in situations where either nonvisual information or one of four kinds of visual information was present. Both visual and nonvisual information were effective in disambiguating the direction of depth within the simulated surface. Real perspective shape transformations affecting the elements of the display were most effective in disambiguating the display.

Adult↗
PubMed1996

Spatial filter combination in human pattern vision: channel interactions revealed by adaptation.

Above threshold, two superimposed sinusoidal gratings of the same spatial frequency (eg 1 cycle deg-1), of equal moderate contrast (eg C1 = C2 = 6%), and with orientations of +/- 45 degrees, usually look like a compound structure containing vertical and horizontal edges (ie a blurred checkerboard). These feature orientations are very different from the dominant filter orientations in a wavelet-type (eg simple-cell) transform of the stimulus, and so present a serious challenge to conventional models of orientation coding based on labelled linear filters. Previous experiments on perceived structure in static plaids have led to the view that the outputs of tuned spatial filters are combined in a stimulus-dependent way, before features such as edges are extracted. Here an adaptation paradigm was used to investigate the cross-channel interactions that appear to underlie the spatial-filter-combination process. Reported are two aftereffects of selective adaptation: (i) adaptation to a 1 cycle deg-1 plaid whose component orientations are intermediate to those in a 1 cycle deg-1 test plaid 'breaks' perceptual combination of the components in the test plaid; (ii) adapting to a 3 cycles deg-1 plaid whose component orientations match those in a 1 cycle deg-1 test plaid facilitates perceptual combination of the components in the test plaid. The results are taken as evidence that spatial channels remote from those most responsive to a test plaid play a crucial role in determining whether the test plaid segments or coheres perceptually.

Adaptation, Ocular↗
PubMedDate not supplied

[Global analysis strategies. Toward the genetic management of neoplasias].

Biomedical research in oncological diseases, particularly focused on the study and understanding of the molecular mechanisms involved in cellular transformation, is opening new possibilities for the development of new and more efficient strategies for diagnosis and treatment. The generation and practical application of the results derived from molecular genetic studies in cancer, has evolved in parallel with the development of technological tools that allow us to get a global vision of diverse cellular processes, both in the normal and pathological states. This combination of basic research and technological application, has created methodologies that allow us to analyze the three principal levels of Molecular Genetics, the Genome (DNA, archive of the genetic information), the Transcriptome (RNA, expression of the genetic information), and finally, the Proteome (proteins, functional aspect of the genetic information). The vast amount of information obtained due to these advancements has begun to modify our fundamental vision about oncological diseases, and together with the traditional analytic tools, they hold the promise of changing the ways we classify, detect, diagnose and treat cancer. In this review, we present some of this methods for global genetic analysis, involving the three levels of genetic organization: the genome, with the Human Genome Project, comparative genomic hybridization and chromosome painting; the Transcriptome, with Serial analysis of Gene Expression and DNA microarrays; and the proteome, with bidimensional protein electrophoresis and antibody-microarrays. In each case, together with a brief description of the method, we also present the impact of every one of them on the study and management of neoplastic diseases.

Chromosome Painting↗