scholarly journals Physically Consistent Scar Tissue Dynamics from Scattered Set of Data: A Novel Computational Approach to Avoid the Onset of the Runge Phenomenon

2021 ◽  
Vol 11 (18) ◽  
pp. 8568
Author(s):  
Pier Nicola Sergi ◽  
Natalia De la Oliva ◽  
Jaume del Valle ◽  
Xavier Navarro ◽  
Silvestro Micera
Keyword(s):  
Foreign Body Reaction ◽  
Scar Tissue ◽  
Nerve Fibers ◽  
Artificial Materials ◽  
Complex Biological Process ◽  
Runge Phenomenon ◽  
Standard Procedures ◽  
Low Degree ◽  
Before And After ◽  
Physically Based

The foreign body reaction is a complex biological process leading to the insulation of implanted artificial materials through a capsule of scar tissue. In particular, in chronic implantations of neural electrodes, the prediction of the scar tissue evolution is crucial to assess the implant reliability over time. Indeed, the capsule behaves like an increasing insulating barrier between electrodes and nerve fibers. However, no explicit and physically based rules are available to computationally reproduce the capsule evolution. In addition, standard approaches to this problem (i.e., Vandermonde-based and Lagrange interpolation) fail for the onset of the Runge phenomenon. More specifically, numerical oscillations arise, thus standard procedures are only able to reproduce experimental detections while they result in non physical values for inter-interval times (i.e., times before and after experimental detections). As a consequence, in this work, a novel framework is described to model the evolution of the scar tissue thickness, avoiding the onset of the Runge phenomenon. This approach is able to provide novel approximating functions correctly reproducing experimental data (R2≃0.92) and effectively predicting inter-interval detections. In this way, the overall performances of previous approaches, based on phenomenological fitting polynomials of low degree, are improved.

scholarly journals Pulsations of blue supergiants before and after helium core ignition

2013 ◽  
Vol 9 (S301) ◽  
pp. 321-324
Author(s):  
Jakub Ostrowski ◽  
Jadwiga Daszyńska-Daszkiewicz
Keyword(s):  
Energy Density ◽  
Kinetic Energy ◽  
Kinetic Energy Density ◽  
Low Degree ◽  
Before And After

AbstractWe present results of pulsation analyses of B-type supergiant models with masses of 14 – 18 M⊙, considering evolutionary stages before and after helium core ignition. Using a non-adiabatic pulsation code, we compute instability domains for low-degree modes. For selected models in these two evolutionary phases, we compare properties of pulsation modes. Significant differences are found in oscillation spectra and the kinetic energy density of pulsation modes.

Barbiturates depress vagal motor pathway to ferret trachea at ganglia

1982 ◽  
Vol 53 (1) ◽  
pp. 253-257 ◽  
Author(s):  
B. E. Skoogh ◽  
M. J. Holtzman ◽  
J. R. Sheller ◽  
J. A. Nadel
Keyword(s):  
Neuromuscular Junction ◽  
Vagus Nerve ◽  
Muscle Tension ◽  
Postsynaptic Membrane ◽  
Nerve Fibers ◽  
Motor Pathway ◽  
Parasympathetic Ganglia ◽  
Before And After ◽  
Nerve Muscle

To determine which site in the vagal motor pathway to airway smooth muscle is most sensitive to depression by barbiturates, we recorded isometric muscle tension in vitro and stimulated the vagal motor pathway at four different sites before and after exposure to barbiturates. In isolated tracheal rings from ferrets, we stimulated muscarinic receptors in the neuromuscular junction by exogenous acetylcholine, postganglionic nerve fibers by electrical fluid stimulation, and the postsynaptic membrane in ganglia by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP). We also developed a tracheal nerve-muscle preparation to stimulate preganglionic fibers in the vagus nerve electrically. Activation of ganglia by DMPP or by vagus nerve stimulation was depressed by barbiturates at 10-fold lower concentrations than those depressing the activation of postganglionic nerves or the neuromuscular junction. These findings suggest that the postsynaptic membrane in parasympathetic ganglia is the site in the vagal motor pathway most sensitive to depression by barbiturates.

Functional organization of ciliary muscle in the cat

1962 ◽  
Vol 203 (5) ◽  
pp. 857-859 ◽  
Author(s):  
Harris Ripps ◽  
Irwin M. Siegel ◽  
William B. Getz
Keyword(s):  
Functional Organization ◽  
Muscle Cells ◽  
Nerve Fibers ◽  
Fixed Number ◽  
Ciliary Muscle ◽  
Frequency Variation ◽  
Efferent Nerve ◽  
Ocular Accommodation ◽  
Before And After ◽  
Stimulation Of

Ocular accommodation was elicited by electric stimulation of the ciliary ganglion in cats. The responses to frequency variation were recorded before and after cutting a branch of the postganglionic motor supply to the ciliary muscle. At all stimulus frequencies the responses obtained after section were shown to be a constant fraction of those obtained in the intact preparation. This suggests that a fixed number of muscle cells are affected when a portion of the efferent nerve fibers is cut. It was concluded that smooth ciliary muscle is organized as independent functional units, akin to the motor-unit arrangement of skeletal muscle; a given nerve fiber influences the response of a limited number of muscle cells.

Efficacy of cognitive-behavioral therapy and deep relaxation for children with attention-deficit hyperactivity disorder

2019 ◽  
pp. 19-26
Author(s):  
Nawel Abdesslem ◽  
Sabeur Hamrouni ◽  
Roy Jesse Shephard ◽  
Mohamed Souhaiel Chelly
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Cognitive Behavioral Therapy ◽  
Attention Deficit ◽  
Behavioral Therapy ◽  
Cognitive Behavioral ◽  
Control Group ◽  
Hyperactivity Disorder ◽  
Before And After ◽  
Physically Based ◽  
One Year

Objective: This study made a preliminary exploration of the efficacy of physically-based cognitive-behavioral therapy and deep relaxation for children with attention-deficit hyperactivity disorder (ADHD). Methods: ADHD behavior and cognitive functions were assessed by test D2 and Conner’s scale before and after a one-year physically-based training program. The reliability of test scores was assessed by repeat testing of a control group (CG) of 10 students who did not have ADHD. Children (10 per group) with ADHD were assigned to physically-based cognitive-behavioral therapy and deep relaxation (E1) or physically-based cognitive-behavioral alone (E2). Results: After 52 weeks of treatment, an intra-group comparison showed that E1 and E2 had improved their scores on the test D2, whereas CG showed no significant change. In addition, most participants with ADHD showed a remarkable improvement in their attentional behavior, with group E1 responding better to treatment than group E2. Conclusions: Physically-based cognitive behavioral therapy appears to improve function and social competence in children with ADHD, and should be recommended as an alternative or supplement to pharmaceutical treatment.

False-Positive Titers of Thyroid Autoantibodies in Patients Undergoing Hemodialysis?

1991 ◽  
Vol 37 (12) ◽  
pp. 2153-2154 ◽  
Author(s):  
Ljerka Lukinac ◽  
Zvonko Kusic ◽  
Petar Kes
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
False Positive ◽  
Serum Samples ◽  
Standard Procedures ◽  
Before And After ◽  
Thyroid Function Testing ◽  
Total Triiodothyronine ◽  
The Difference ◽  
Function Testing

Abstract Concentrations of thyroid-related hormones in serum of patients with chronic renal failure are known to be abnormal (1, 2). In our study on thyroid-function testing of patients undergoing hemodialysis, we determined, in addition to concentrations of free and total triiodothyronine, free and total thyroxin, “reverse” triiodothyronine, and thyroxin-binding globulin, the titers of thyroglobulin and microsomal autoantibodies (TGA and TMA, respectively). The study was provoked by the appearance of an uncommon agglutination pattern in the control wells of some samples from patients with chronic renal failure during the standard procedures of detecting TGA and TMA with hemagglutination methods (Thymune-T and Thymune-M assays from Welcome, London, U.K.). For these samples we were not certain whether positive titers for TGA and (or) TMA represented false-positive or true-positive values. Therefore, we assayed the absorbed serum samples and samples after addition of excess nonspecific immunoglobulin. Furthermore, we wanted to determine the difference in TGA and TMA titers of serum samples before and after hemodialysis.

scholarly journals Distinguishing hair cell from neural potentials recorded at the round window

2014 ◽  
Vol 111 (3) ◽  
pp. 580-593 ◽  
Author(s):  
Mathieu Forgues ◽  
Heather A. Koehn ◽  
Askia K. Dunnon ◽  
Stephen H. Pulver ◽  
Craig A. Buchman ◽  
...  
Keyword(s):  
Hair Cell ◽  
Kainic Acid ◽  
Hair Cells ◽  
Phase Locking ◽  
Round Window ◽  
Nerve Fibers ◽  
Neural Firing ◽  
Low Frequencies ◽  
Before And After ◽  
Different Sources

Almost all patients who receive cochlear implants have some acoustic hearing prior to surgery. Electrocochleography (ECoG), or electrophysiological measures of cochlear response to sound, can identify remaining auditory nerve activity that is the basis for this residual hearing and can record potentials from hair cells that are no longer functionally connected to nerve fibers. The ECoG signal is therefore complex, being composed of both hair cell and neural signals. To identify signatures of different sources in the recorded potentials, we collected ECoG data across frequency and intensity from the round window of gerbils before and after treatment with kainic acid, a neurotoxin. Distortions in the recorded waveforms were produced by different sources over different ranges of frequency and intensity. In response to tones at low frequencies and low-to-moderate intensities, the major source of distortion was from neural phase-locking that was sensitive to kainic acid. At high intensities at all frequencies, the distortion was not sensitive to kainic acid and was consistent with asymmetric saturation of the hair cell transducer current. In addition to loss of phase-locking, changes in the envelope after kainic acid treatment indicate that sustained neural firing combines with receptor potentials from hair cells to produce the envelope of the response to tones. These results provide baseline data to interpret comparable recordings from human cochlear implant recipients.

scholarly journals Population dynamics and intra-litter transmission patterns of Isospora suis in suckling piglets under on-farm conditions

Parasitology ◽  
2007 ◽  
Vol 135 (3) ◽  
pp. 395-405 ◽  
Author(s):  
S. SOTIRAKI ◽  
A. ROEPSTORFF ◽  
J. P. NIELSEN ◽  
C. MADDOX-HYTTEL ◽  
C. ENøE ◽  
...  
Keyword(s):  
Effective Means ◽  
Age At Onset ◽  
Contamination Level ◽  
Oocyst Excretion ◽  
Infection Dynamics ◽  
Standard Procedures ◽  
Management Procedures ◽  
Before And After ◽  
Suckling Piglets ◽  
Isospora Suis

SUMMARYThe aim of this study was to investigate the intra-litter infection dynamics of Isospora suis under natural conditions, and to study any association between parasite transmission and the contamination level of the farrowing pen by applying different interventions in order to reduce the transmission of I. suis infection within the litter. The study was divided in 2 trials including in total 22 litters (254 piglets). The first trial included 4 litters (where standard procedures practiced routinely on the farm piglets were applied) and the piglets were followed coprologically from farrowing until 2 weeks after weaning. The sows of those litters were also examined at various intervals before and after farrowing. The second trial included the application of 3 different management procedures: (A) standard farm hygiene and management procedures, (B) standard farm hygiene and management procedures+the first piglets found to excrete I. suis oocysts in each pen were removed from the pen, and (C) reduced cleaning. Each procedure was studied in 2 litters. This was replicated 3 times to yield a total of 18 litters. The results suggested that (i) the sow does not play an important role in transmission of I. suis in the farrowing pen; (ii) in natural infections, both the age of the piglet age at onset of oocyst excretion and the oocyst excretion patterns may vary considerably; (iii) the course of oocyst excretion or development of diarrhoea is related to the time of initial infection and (iii) piglets, which are heavy at birth, are more prone to acquire I. suis infection. Moreover, it was demonstrated that cleaning could be an effective means of restricting the spread of the parasite within the litter and thus the development of diarrhoea.

scholarly journals Prevalence and Antimicrobial Susceptibility Pattern of Bacteria Isolated from Mobile Phones of Health Care Professionals Working in Gondar Town Health Centers

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Muktar Gashaw ◽  
Daniel Abtew ◽  
Zelalem Addis
Keyword(s):  
Health Care ◽  
Mobile Phones ◽  
Antimicrobial Susceptibility ◽  
Health Care Professionals ◽  
Prevention Measures ◽  
Susceptibility Pattern ◽  
Antimicrobial Susceptibility Pattern ◽  
Standard Procedures ◽  
Before And After ◽  
Gondar Town

Background. Mobile phones of health professionals can harbor various potential pathogens and become exogenous sources of infection for the patients, self, and family members. This study assessed the frequency and antimicrobial susceptibility pattern of bacteria from mobile phones of health care workers. Methods. In this crosssectional study a total of 58 health care professionals mobile phones were swabbed before and after decontamination with 70% alcohol and assessed for contamination with bacteria. Bacterial isolation, identification, and antimicrobial susceptibility test was done as per the standard procedures. Results. About 98% of the mobile phones assessed in this study were contaminated with bacteria. Coagulase negative Staphylococci, S. aureus, and E. coli were the most frequently isolated bacteria. Decontamination with 70% alcohol significantly decreased the rate of contamination from 98.3% to 55.2% (χ2=30.17;P-value<0.0001). About 17% of the isolates were resistant to two drugs. Conclusion. Appropriate infection prevention measures should be taken to minimize the risk that could be associated with mobile phones since the rate of contamination was high. Decontamination with 70% alcohol was effective in minimizing bacterial contamination of mobile phones so it should be used as a decontaminant agent for these apparatuses.

scholarly journals Mechanical matching of implant to host minimises foreign body reaction

2019 ◽  
Author(s):  
Alejandro Carnicer-Lombarte ◽  
Damiano G. Barone ◽  
Ivan B. Dimov ◽  
Russell S. Hamilton ◽  
Malwina Prater ◽  
...  
Keyword(s):  
Foreign Body ◽  
Foreign Body Reaction ◽  
Scar Tissue ◽  
Host Tissue ◽  
Medical Implants ◽  
Implant Surface ◽  
Biomedical Implant ◽  
Manufacturing Techniques ◽  
Implant Coatings

AbstractMedical implants offer a unique and powerful therapeutic approach in many areas of medicine. However, their lifetime is often limited as they may cause a foreign body reaction (FBR) leading to their encapsulation by scar tissue1–4. Despite the importance of this process, how cells recognise implanted materials is still poorly understood5, 6. Here, we show how the mechanical mismatch between implants and host tissue leads to FBR. Fibroblasts and macrophages, which are both crucially involved in mediating FBR, became activated when cultured on materials just above the stiffness found in healthy tissue. Coating implants with a thin layer of hydrogel or silicone with a tissue-like elastic modulus of ∼1 kPa or below led to significantly reduced levels of inflammation and fibrosis after chronic implantation both in peripheral nerves and subcutaneously. This effect was linked to the nuclear localisation of the mechanosensitive transcriptional regulator YAP in vivo. Hence, we identify the mechanical mismatch between implant and tissue as a driver of FBR. Soft implant coatings matching the mechanical properties of host tissue minimized FBR and may be used as a novel therapeutic strategy to improve long-term biomedical implant stability without extensive modification of current implant manufacturing techniques, thus facilitating clinical translation.One sentence summaryForeign body reaction to medical implants can be avoided by matching the stiffness of the implant surface to that of the host tissue.

Involvement of capsaicin-sensitive nerves in regulating the hormone and glucose metabolic response to endotoxin

1997 ◽  
Vol 273 (2) ◽  
pp. E328-E335 ◽  
Author(s):  
A. E. Morgan ◽  
C. H. Lang
Keyword(s):  
Metabolic Response ◽  
Critical Role ◽  
Glucose Production ◽  
Nerve Fibers ◽  
Sensory Nerves ◽  
Whole Body ◽  
Adult Rats ◽  
Glucose Flux ◽  
Before And After ◽  
Experiment Control

This study investigated the role that sensory nerves play in mediating the hormone and glucose metabolic response to endotoxin [lipopolysaccharide (LPS)]. Adult rats were pretreated subcutaneously with capsaicin to selectively destroy primary sensory afferent nerve fibers. Ten days later, [3-3H]glucose was infused intravenously to assess whole body glucose flux before and after the intravenous injection of Escherichia coli LPS (100 micrograms/100 g body wt). Control animals responded to LPS with characteristic increases in the plasma concentration of glucose (91%) and lactate (threefold) and elevations in the rates of glucose appearance and disappearance (77%). In capsaicin-treated rats, the maximal LPS-induced increase in these parameters was attenuated by 50-60%. In addition, these animals were hypoglycemic at the conclusion of the experiment. Control animals demonstrated early and sustained elevations in circulating levels of corticosterone, glucagon, and catecholamines. In contrast, the early LPS-induced elevation in epinephrine and norepinephrine, and to a lesser extent glucagon, was completely absent or greatly impaired by capsaicin pretreatment. In a separate study, the epinephrine-induced increase in glucose flux was blunted by 75% in capsaicin-treated rats. These data indicate that sensory afferent neurons play a critical role in the early secretory response of glucagon and catecholamines, the maintenance of tissue catecholamine responsiveness, and the stimulation of glucose production after LPS.

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