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Results for “multimodal integration”

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PubMed2004

Analysis of characteristics of bent rib waveguides.

With a perfectly matched layer boundary treatment, a semivectorial finite-difference method is used to calculate the eigenmodes of a single-mode (SM) or multimode (MM) bent rib waveguide. A detailed analysis is given for the dependence of the bending losses (including the pure bending loss and the transition loss) on geometrical parameters of the bent rib waveguide such as the rib width, the rib height, and the bending radius. The characteristics of the higher-order modes are analyzed. It is shown that the bending loss of the fundamental mode can be reduced effectively by increasing the width and height of the rib. For an integrated device, undesired effects due to the higher-order modes of a MM bent waveguide can be removed by appropriate choice of the geometrical parameters. An appropriately designed MM bent waveguide is used to reduce effectively the bending loss of the fundamental mode, and a low-loss SM propagation in a MM bent waveguide is realized when the bending losses of the higher-order modes are large enough.

Journal Article↗

PubMed1991

Role of a multichannel electrotactile speech processor in a cochlear implant program for profoundly hearing-impaired adults.

Four profoundly hearing-impaired adults who did not meet current selection criteria for implantation at the University of Melbourne were each fitted with a wearable multichannel electrotactile speech processor (Tickle Talker). The subjects were evaluated with a test battery of speech discrimination tests subsequent to training in use of the device. Thresholds for detection of pure tones were lower for the Tickle Talker than for hearing aids across the frequency range 250 to 4000 Hz. Mean speech detection thresholds for the Ling 5-sound test showed that all sounds were detected by users of the electrotactile device at normal conversational speech intensity levels. Mean speech discrimination scores were significantly higher (p less than 0.05) in the tactually aided condition as compared with the tactually unaided for identification of vowels and consonants, on open-set words, open-set sentences, and on connected discourse tracking. Mean scores increased by 20% for vowels, 19% for consonants, 30% for open-set words, and 25% for open-set sentences when the Tickle Talker was used in a multimodal combination with lipreading or lipreading and hearing aids. Speechtracking rates for three subjects showed increases of from 18 to 28 wpm when the tactile device was used. Comparison of tactually aided versus unaided tracking rates for two subjects with long-term experience shows continuing improvement with additional experience with the device. These results demonstrate that hearing-impaired adults not meeting selection criteria for cochlear implantation may benefit from use of an electrotactile speech processor, and highlight the potential benefits from integration of such devices into cochlear implant programs for profoundly hearing-impaired patients.

Acoustics↗

PubMed1994

Recent developments in radioimmunotherapy.

With the advent of monoclonal antibody techniques, there has been renewed interest in RIT as a treatment modality in patients with a variety of tumour types. There has been a considerable research effort to increase understanding of the scientific basis of such therapy at all levels. Antibody, chelator and radioisotope factors are all the subject of research aimed at producing a potent effector system capable of maximal target cell kill with acceptable normal tissue toxicity. Improved knowledge of the host and tumour factors which limit access to the target cell offers the possibility of optimizing targeting and increasing the therapeutic index. Target cell factors that influence response to low dose rate RIT have been elucidated and provide an opportunity to integrate the treatment modality into radical therapy regimens. A number of Phase I and II trials have now been performed in various tumour types. The results have been promising but, as yet, the prospect of radical RIT remains a research goal. Before it can be achieved it will be necessary to improve specific tumour cell targeting and to increase both the initial dose rates and the total dose delivered to tumour deposits. Until such time, it is likely that RIT will be incorporated into multimodality protocols to deliver a moderate (10-20 Gy) tumour boost, or in an adjuvant setting in patients with minimal residual disease.

Antibodies, Monoclonal↗

PubMed2006

A simplified method to integrate metabolic images in stereotactic procedures using a PET/CT scanner.

We have developed a method that needs only the computed tomography (CT) indicator box to coregister positron emission tomography (PET) images and integrates this information with magnetic resonance imaging. The study was performed using a PET/CT scanner. A standard CT bed adapter was attached to the scanner couch. Then, the patient, with the Leksell G frame fixed, was positioned into the scanner with the CT indicator box. PET images were acquired using either [18F]fluorodeoxyglucose or [11C]choline as radioisotopes. After acquisition, CT and PET images were exported in DICOM 3 standard and transferred to a dedicated workstation via data link. Homemade software was implemented for multimodal image fusion. PET images were overwritten to their corresponding CT point values using a threshold algorithm, maintaining the stereotactic CT markers. The use of a CT indicator simplifies the procedure, because there is no need for a radioactive solution filling the indicator box. This method was tested first using a phantom and then in patients. The localization accuracy of the PET images is limited only by the slice thickness.

Aged↗

PubMed2006

An integrated biological approach to nuclear receptor signaling in physiological control and disease.

The nuclear receptors (NRs)--vitamin D receptor (VDR); peroxisome proliferator-activated receptor (PPAR) alpha, delta, gamma; and pregnane X receptor (PXR)--act as sensors for various molecules encountered by the body on a daily basis. The effects of these ligands can be understood by the fact that numerous genes involved in the cellular processes, such as general homeostasis, growth, and defense against microbes, are under the control of these five NRs. The target gene and protein expression patterns of VDR, PPARs, and PXR; the resulting changes in metabolite levels; and their physiological consequences create a network that can be monitored by high-throughput methods and analyzed by multimodal approaches, such as systems biology. We suggest that the fine regulation of this NR network is specific to each human individual and depends, in part, on the constellation of regulatory small nucleotide polymorphisms (SNPs) in his or her genome. When regulatory SNPs affect NRs response elements, lifetime exposure to food components will have different accumulative consequences on the expression of the respective NR target genes. These differences will influence the individual's susceptibility to aging-related diseases, such as type 2 diabetes, atherosclerosis, cancer, and osteoporosis. Furthermore, it is anticipated that systems biology methods will also help to identify the most critical genes, proteins, or metabolites in the NR network that will serve as biomarkers for the early detection of these diseases.

Computational Biology↗

PubMed2004

Early use of artificial sensibility in hand transplantation.

Hands were transplanted from brain-dead donors for the treatment of two male unilateral amputees, aged 35 years and 32 years, involved in the Italian Hand Transplantation Programme. Each had lost his right dominant hand, in a farming accident and an explosion, respectively. In one case artificial sensibility was applied postoperatively using a Sensor Glove that transformed vibrotactile stimuli induced by touch, to stereophonic vibroacoustic stimuli perceived through earphones. The principle is based on the brain's capacity for multimodal plasticity, implying that deprivation of one sense (somatosensory) can be compensated for by another sense (auditory). Functional magnetic resonance images (fMRI) taken at regular intervals showed that cortical remodelling of the transplanted hand within the sensory-motor maps occurred early in the patient who used the artificial sensibility regimen compared with the one who did not. We conclude that postoperative use of a device using hearing as a substitution for sensation in hand transplantation may have considerable potential value for speeding up cortical integration of a transplanted hand.

Adult↗

PubMed1998

Phasic flow events at the aortic isthmus-ductus arteriosus junction and branch pulmonary artery evaluated by multimodal ultrasonography in fetal lambs.

OBJECTIVES: We assessed the phasic flow and interaction between the pulmonary trunk and aortic isthmus flow at their junction in the lamb fetus in late gestation and also assessed the interaction of the left pulmonary artery branch. STUDY DESIGN: With echocardiographic and Doppler ultrasonographic and saline-contrast techniques, we studied 7 fetal lambs with arterial and venous catheters in place to assess direction, velocity, and timing of flow at the aortic isthmus, ductus arteriosus, and proximal left pulmonary artery. RESULTS: At the isthmus-ductus junction, ductus systolic flow occurred later (0.048 +/- 0.006 second, mean +/- SD) and accelerated more slowly than isthmus flow but with higher velocities (peak 70.7 +/- 7.1 vs 63.1 +/- 6.3 cm/s, velocity time integral 5.7 +/- 1.2 vs 4.5 +/- 1.3 cm, respectively; P <.001). There was a small degree of late systolic flow reversal and admixture from both sources. Signals from the left pulmonary arterial branch showed a sharp, brief systolic forward flow with a peak velocity of 48.8 +/- 9.1 cm/s, followed by late systolic and diastolic flow reversal with a peak velocity of 23.5 +/- 8.7 cm/s. CONCLUSION: The differences in the flow timing may be the result of different timing of ventricular contraction, resistances in the vascular beds, and ductus constriction, both anatomic and physiologic.

Animals↗

PubMed2001

Thoracic and thoracoabdominal aortic aneurysm repair: use of evoked potential monitoring in 118 patients.

PURPOSE: Paraplegia is the most dreaded and severe complication of surgery on the descending thoracic aorta (TAA) and thoracoabdominal aorta (TAAA). The functional integrity of the spinal cord can be monitored by means of intraoperative recording of myogenic-evoked responses after transcranial electrical stimulation (tcMEP) and somatosensory-evoked potential (SEP) monitoring. In this study, we evaluated the results of evoked potential monitoring and the adequacy of the strategy followed. METHOD: The spinal cord of 118 patients (78 men; age, 65 +/- 12 years; 79 TAAAs, 39 TAAs) undergoing surgery on the TAA or TAAA was monitored with tcMEP and SEP. Spinal cord protection was achieved by means of a multimodality approach: moderate hypothermia (32 degrees C rectal temperature), continuous cerebrospinal fluid drainage to keep the pressure less than 10 mm Hg, reimplantation of intercostal arteries, left ventricular bypass grafting, and staged clamping. In the case of evoked potential changes more than 50% of baseline, the strategy was adjusted: reattachment of more segmental arteries when technically feasible, higher distal and proximal perfusion pressures, and enhanced cerebrospinal fluid drainage. RESULTS: Forty-two of 118 patients (35.6%) had a more than 50% of baseline tcMEP reduction during cross-clamping. At this point, only 5 of those 42 cases were also associated with SEP reduction of more than 50% of baseline. On the basis of the tcMEP findings, the strategy was adjusted. Five patients had postoperative paraplegia (4.2%). CONCLUSION: tcMEP monitoring seems to be a useful adjunct of the protective techniques and may cause substantial adjustments in strategy, reducing the incidence of postoperative paraplegia.

Aged↗

PubMed2004

Nonlinear dynamics of semiconductor lasers with active optical feedback.

An in-depth theoretical as well as experimental analysis of the nonlinear dynamics in semiconductor lasers with active optical feedback is presented. Use of a monolithically integrated multisection device of submillimeter total length provides access to the short-cavity regime. By introducing an amplifier section as a special feature, phase and strength of the feedback can be separately tuned. In this way, the number of modes involved in the laser action can be adjusted. We predict and observe specific dynamical scenarios. Bifurcations mediate various transitions in the device output, from single-mode steadystate to self-pulsation and between different kinds of self-pulsations, reaching eventually chaotic behavior in the multimode limit.

Journal Article↗

PubMed1989

Anatomical investigation of projections to the basis pontis from posterior parietal association cortices in rhesus monkey.

The projections to the basis pontis from cytoarchitectonically defined subregions of the superior (SPL) and inferior (IPL) parietal lobules were investigated in 14 rhesus monkeys by using the anterograde tracing techniques of autoradiography and horseradish peroxidase histochemistry. The results of our study confirm and complement available information regarding the parietopontine projections. The projections are found in clusters distributed in lamellae approximately concentric to the peduncle. They are directed most heavily towards the peripeduncular and lateral nuclei of the pons. There are also lesser, but nevertheless substantial projections to other nuclei including the intrapeduncular, ventral, dorsolateral, extreme dorsolateral, and dorsal nuclei. The dorsomedial, paramedian, and NRTP nuclei receive only minor projections. The SPL projections are relatively widespread with respect to the more focussed IPL projections. The IPL projections are, in general, situated more laterally and at more rostral levels of the pontine nuclei than are those of the SPL. The sulcal cortex of the SPL (area PEa) favors the dorsolateral, extreme dorsolateral, and ventral nuclei compared to the light projections to these nuclei from the convexity of the SPL. The sulcal cortex of the IPL, area POa, differs from the gyral cortex in favoring the ventral and extreme dorsolateral nuclei. The rostral IPL differs from the caudal IPL in that the intrapeduncular nucleus receives projections only from rostral regions, while the lateral nucleus receives projections preferentially from caudal regions. The pontine projections from the medial SPL, area PGm, are unique in the parietal lobe in that they include the paramedian nucleus. Projections arising from multimodal regions located caudally in the SPL (areas PEa and PGm) and IPL (areas PG and Opt) are more strongly represented and more laterally placed within the pontine nuclei than projections arising from more rostral, unimodal, posterior parietal regions. The heavy projections to the pontine nuclei from the posterior parietal cortex, and particularly from those caudal parietal regions that have prominent associative and limbic connections, seem to suggest that the corticopontocerebellar pathways permit a cerebellar contribution not only to the coordination of movement, but also to the modulation and integration of higher function.

Animals↗

PubMed2002

The neurophysics of consciousness.

Consciousness combines information about attributes of the present multimodal sensory environment with relevant elements of the past. Information from each modality is continuously fractionated into distinct features, processed locally by different brain regions relatively specialized for extracting these disparate components and globally by interactions among these regions. Information is represented by levels of synchronization within neuronal populations and of coherence among multiple brain regions that deviate from random fluctuations. Significant deviations constitute local and global negative entropy, or information. Local field potentials reflect the degree of synchronization among the neurons of the local ensembles. Large-scale integration, or 'binding', is proposed to involve oscillations of local field potentials that play an important role in facilitating synchronization and coherence, assessed by neuronal coincidence detectors, and parsed into perceptual frames by cortico-thalamo-cortical loops. The most probable baseline levels of local synchrony, coherent interactions among brain regions, and frame durations have been quantitatively described in large studies of their age-appropriate normative distributions and are considered as an approximation to a conscious 'ground state'. The level of consciousness during anesthesia can be accurately predicted by the magnitude and direction of reversible multivariate deviations from this ground state. An invariant set of changes takes place during anesthesia, independent of the particular anesthetic agent. Evidence from a variety of neuroscience areas supporting these propositions, together with the invariant reversible electrophysiological changes observed with loss and return of consciousness, are used to provide a foundation for this theory of consciousness. This paper illustrates the increasingly recognized need to consider global as well as local processes in the search for better explanations of how the brain accomplishes the transformation from synchronous and distributed neuronal discharges to seamless global subjective awareness.

Brain↗

PubMedDate not supplied

Multimodality paradigms for a healthy multimodality society.

The American Radium Society encourages the study of cancer in all its aspects, encourages liaison among the various medical specialists and allied scientists, and thereby champions multimodality oncologic care. Past and present membership rolls of the Society read like a "Who's Who" of cancer care and include distinguished physicians and allied scientists whose primary focus spans the spectrum of oncologic subspecialties; however, the current distribution of areas of expertise may not necessarily be optimal. Moreover, the practice of medicine constantly is changing, and we, as a society, should be prepared to evolve with it. For example, treatment of cancers arising in the head and neck region has changed dramatically during the past decade. The successful integration of concurrent chemotherapy with radiation therapy has created new paradigms for optimal care. These paradigms potentially decrease the risk of distant metastases, improve the local-regional control of disease, increase the likelihood of organ preservation, and reduce the risk posed by microscopic-sized unresected disease. Yet, much remains unknown, some of the available data appear contradictory, and much is left to do. Similar analysis persuasively argues that other groups that have specific expertise must also play a vital role in modern oncologic care, including radiation biologists, medical physicists, and molecular biologists. Yet, the current environment creates formidable obstacles to participation in the American Radium Society's mission. We must improve our understanding of these barriers and implement original solutions to ensure that our society remains in the forefront of progress in the fight against cancer. In particular, programs to increase the educational reach of the ARS need to be devised, implemented, and nurtured. The ARS has a long, proud history, but we should not seek to live in its past. We must seek continuously and welcome enthusiastically changes in the Society that will align the ARS with paradigms of cutting-edge oncologic care.

Combined Modality Therapy↗

PubMed2003

Multimodal management - of value in fulminant acute pancreatitis?

BACKGROUND: The multiple organ dysfunction syndrome (MODS) is the major cause of morbidity and mortality associated with acute pancreatitis. Presently, therapy is merely organ supportive as no effective therapy against underlying causative pathophysiological mechanisms exists. AIMS: To evaluate the effect of treatment with a platelet-activating factor inhibitor (PAFI), a monoclonal antibody against platelet endothelial cell adhesion molecule 1 (PECAM-1-MAb) and an oxygen free radical scavenger (N-acetylcystein; NAC), alone or in combination, on systemic organ dysfunction in experimental acute pancreatitis. METHODS: Severe acute pancreatitis was induced in rats by the intraductal administration of taurodeoxycholate. Treatment was given after 1 or 3 h, and evaluations were performed 6 h after induction. Organ dysfunction was evaluated by means of endothelial integrity impairment expressed as endothelial barrier leakage index. RESULTS: Severe acute pancreatitis caused a significant impairment in endothelial integrity in all organs studied and decreased levels of protease inhibitors compared to controls. The endothelial barrier impairment was significantly ameliorated by all treatment modalities, either given early or later. Combinations of NAC and the PECAM-1-MAb or the PECAM-1-MAb and the PAFI were the only schedules to restore endothelial barrier integrity to normal levels in most of the organs studied. CONCLUSION: Combination therapy with NAC and PECAM-1-MAb and/or PAFI may offer effective, causative-directed supplements to organ-supportive therapy of MODS in severe acute pancreatitis.

Acetylcysteine↗

PubMed2002

Local frequency representations for robust multimodal image registration.

Automatic registration of multimodal images involves algorithmically estimating the coordinate transformation required to align the data sets. Most existing methods in the literature are unable to cope with registration of image pairs with large nonoverlapping field of view (FOV). We propose a robust algorithm, based on matching dominant local frequency image representations, which can cope with image pairs with large nonoverlapping FOV. The local frequency representation naturally allows for processing the data at different scales/resolutions, a very desirable property from a computational efficiency view point. Our algorithm involves minimizing-over all rigid/affine transformations--the integral of the squared error (ISE or L2 E) between a Gaussian model of the residual and its true density function. The residual here refers to the difference between the local frequency representations of the transformed (by an unknown transformation) source and target data. We present implementation results for image data sets, which are misaligned magnetic resonance (MR) brain scans obtained using different image acquisition protocols as well as misaligned MR-computed tomography scans. We experimently show that our L2E-based scheme yields better accuracy over the normalized mutual information.

Brain↗

PubMed1998

Dysautonomia in fatal familial insomnia as an indicator of the potential role of the thalamus in autonomic control.

Fatal familial insomnia (FFI) is characterized by insomnia, dysautonomia, disruption of circadian rhythms, and motor dysfunction. The typical neuropathological findings in FFI are severe neuronal depletion in the mediodorsal (MD) and anteroventral nuclei of the thalamus. The interaction between the thalamus and central autonomic control mechanisms is poorly understood. The central autonomic areas include the anterior cingulate and insular cortices; amygdala, paraventricular nucleus, dorsomedial nucleus, and lateral hypothalamic area; periaqueductal gray; parabrachial nucleus; ventrolateral medulla; and nucleus of the solitary tract. Several nuclei of the thalamus have connections with areas of the central autonomic network. The paraventricular nucleus (PVT) projects to the medial prefrontal cortex, and receives multimodal visceral and somatosensory inputs. The MD nucleus is connected with several "limbic" areas involved in autonomic control. The autonomic manifestations of FFI are exaggerated sympathetic activation with preserved parasympathetic drive to the cardiovascular system. This reflects an exaggerated sympathetic drive from supramedullary structures. Bicuculline, administered into the MD, elicits an increase in arterial pressure and heart rate. The medial portion of the MD may share with the PVT a relay function for circuits controlling autonomic responses. MD involvement in FFI suggests a role of the thalamus in central autonomic and other integrative functions.

Autonomic Nervous System↗

PubMed2004

Heterodyne mixing of two far-infrared quantum cascade lasers by use of a point-contact Schottky diode.

We demonstrate heterodyne mixing of two free-running, multimode, 3.3-THz quantum cascade lasers by use of a point-contact Schottky diode. By temperature tuning the emission wavelength of one laser, a difference frequency signal spanning the 2-4-GHz range is obtained, with a signal-to-noise ratio of 30 dB. The frequency of the heterodyne signal is subject to random fluctuations of a few megahertz, principally from instabilities in the temperatures of the devices. From single-shot measurements we derive an instantaneous linewidth for a single Fabry-Perot mode of 20 kHz, corresponding to an integration time of 3.6 ms.

Journal Article↗

PubMed2026

Artificial Intelligence for Natural Products Discovery and Development.

Natural products (NPs) remain a cornerstone of modern drug discovery, offering stereochemical complexity and diverse bioactivities that precisely modulate therapeutic targets, refined through billions of years of evolution. However, their research has long been hindered by inefficient, empirical workflows, high resource consumption, structural complexity, and the "multicomponent, multi-target" nature of their mechanisms. The exponential growth of genomic, metabolomic, and spectral data has overwhelmed conventional analytical methods, exposing critical bottlenecks in handling high-dimensional, heterogeneous datasets that exceed human interpretive capacity. Artificial intelligence (AI) is emerging as a transformative paradigm to address these challenges, integrating multi-omics and chemical data to shift NP research from fragmented empiricism toward mechanism-driven, precision-oriented development. By leveraging deep learning architectures- including graph neural networks, Transformers, and diffusion-based generative models-AI enables systematic decoding of NP biosynthesis, automated structure elucidation, rational target identification, knowledge extraction from vast unstructured scientific literature, and de novo molecular design. This review comprehensively surveys recent advances in AI applications across the full NP discovery and development pipeline, encompassing genome mining, structure-based and ligand-based virtual screening, multimodal structural characterization, lead optimization, and biosynthetic pathway engineering. We further examine the emerging roles of protein-centric, molecule- centric, and multimodal foundation models, as well as large language models, in bridging genotype-to-chemotype gaps and unlocking unstructured scientific knowledge. Finally, we discuss critical challenges including data scarcity, representational limitations for complex stereochemistry, physical plausibility in generative models, and the urgent need for experimental validation, while outlining future directions toward autonomous experimentation, closed-loop optimization, and human-AI collaborative discovery.

Artificial intelligence↗

PubMed1995

Correlative morphologic and functional imaging for diagnosis, staging and follow up in AIDS: an overview.

The immunocompromised patient can be affected by different opportunistic infections and tumors, that can involve all organ systems, and particularly, the central nervous system, the respiratory system, the gastrointestinal tract. The extreme variability of AIDS presentations requires a specific preparation and cooperation between the different diagnostic imaging specialists and a close collaboration with the clinicians. With AIDS, different morphologic and functional imaging techniques can be used for detection of disease sites, assessment of the extent of the disease and monitoring of disease changes over time and response to treatment. The complexity of AIDS presentations is such that full integration of the complementary information obtained with different techniques could be most useful. Image registration (coregistration, fusion) indicates approaches where precise spatial cross-references are obtained, in order to combine the information acquired with different imaging modalities, in particular by blending morphologic CT/MRI data with functional SPET/PET data. In this paper, an overview of the developments in the field of "image fusion" follows some comments on the results of morphologic and functional assessment of brain, chest and abdominal diseases in the course of AIDS, as illustrative examples of the potential benefits of multimodality image correlation.

AIDS-Related Opportunistic Infections↗