Iterative shepherding control for agents with heterogeneous responsivity.

In the context of the theory of multi-agent systems, the shepherding problem refers to designing the dynamics of a herding agent, called a sheepdog, so that a given flock of agents, called sheep, is guided into a goal region. Although several effective methodologies and algorithms have been proposed in the last decade for the shepherding problem under various formulations, little research has been directed to the practically important case in which the flock contains sheep agents unresponsive to the sheepdog agent. To fill in this gap, we propose a sheepdog algorithm for guiding unresponsive sheep in this paper. In the algorithm, the sheepdog iteratively applies an existing shepherding algorithm, the farthest-agent targeting algorithm, while dynamically switching its destination. This procedure achieves the incremental growth of a controllable flock, which finally enables the sheepdog to guide the entire flock into the goal region. Furthermore, we illustrate by numerical simulations that the proposed algorithm can outperform the farthest-agent targeting algorithm.

Characteristics of aspiration pneumonia patients in acute care hospitals: A multicenter, retrospective survey in Northern Japan.

BACKGROUND: Pneumonia is a common cause of illness and death of the elderly in Japan. Its prevalence is escalating globally with the aging of population. To describe the latest trends in pneumonia hospitalizations, especially aspiration pneumonia (AP) cases, we assessed the clinical records of pneumonia patients admitted to core acute care hospitals in Miyagi prefecture, Japan. METHODS: A retrospective multi-institutional joint research was conducted for hospitalized pneumonia patients aged ≥20 years from January 2019 to December 2019. Clinical data of patients were collected from the medical records of eight acute care hospitals. RESULTS: Out of the 1,800 patients included in this study, 79% of the hospitalized pneumonia patients were aged above 70 years. The most common age group was in the 80s. The ratio of AP to total pneumonia cases increased with age, and 692 out of 1,800 patients had AP. In univariate analysis, these patients had significantly older ages, lower body mass index (BMI), a lower ratio of normal diet intake and homestay before hospitalization, along with more AP recurrences and comorbidities. During hospitalization, AP patients had extended fasting periods, more swallowing assessments and interventions, longer hospitalization, and higher in-hospital mortality rate than non-AP patients. A total of 7% and 2% AP patients underwent video endoscopy and video fluorography respectively. In multivariate analysis, lower BMI, lower C-reactive protein, a lower ratio of homestay before hospitalization, a higher complication rate of cerebrovascular disease, dementia, and neuromuscular disease were noted as a characteristic of AP patients. Swallowing interventions were performed for 51% of the AP patients who had been hospitalized for more than two weeks. In univariate analysis, swallowing intervention improved in-hospital mortality. Lower AP recurrence before hospitalization and a lower ratio of homestay before hospitalization were indicated as characteristics of AP patients of the swallowing intervention group from multivariate analysis. Change in dietary pattern from normal to modified diet was observed more frequently in the swallowing intervention group. CONCLUSION: AP accounts for 38.4% of all pneumonia cases in acute care hospitals in Northern Japan. The use of swallowing evaluations and interventions, which may reduce the risk of dysphagia and may associate with lowering mortality in AP patients, is still not widespread.

Early neurosyphilis presenting with multiple cranial nerve palsies: A case report of management by combined penicillin-corticosteroid treatment.

Early neurosyphilis commonly appears in basilar meninges, and its meningeal inflammation can spread to neighboring cranial nerves, resulting in some cranial nerve palsies. Herein, we report a case of a 51-year-old man who presented with right peripheral facial nerve palsy. His symptoms completely disappeared with prednisolone monotherapy without antibiotics use and were not exacerbated during clinical treatment. However, 2 months after remission of seventh cranial neuropathy, fifth and eighth cranial neuropathies appeared on the right side. Serologic tests for syphilis were revealed to be abnormal. Finally, the patient was diagnosed with early neurosyphilis with multiple cranial palsies. His neurological symptoms were markedly improved by combined penicillin-corticosteroid treatment. Systemic corticosteroids could be effective as adjunctive therapy to ameliorate neurological sequelae in early neurosyphilis.

Delayed bet-hedging resilience strategies under environmental fluctuations.

Many biological populations, such as bacterial colonies, have developed through evolution a protection mechanism, called bet hedging, to increase their probability of survival under stressful environmental fluctuation. In this context, the concept of preadaptation refers to a common type of bet-hedging protection strategy in which a relatively small number of individuals in a population stochastically switch their phenotypes to a dormant metabolic state in which they increase their probability of survival against potential environmental shocks. Hence, if an environmental shock took place at some point in time, preadapted organisms would be better adapted to survive and proliferate once the shock is over. In many biological populations, the mechanisms of preadaptation and proliferation present delays whose influence in the fitness of the population are not well understood. In this paper, we propose a rigorous mathematical framework to analyze the role of delays in both preadaptation and proliferation mechanisms in the survival of biological populations, with an emphasis on bacterial colonies. Our theoretical framework allows us to analytically quantify the average growth rate of a bet-hedging bacterial colony with stochastically delayed reactions with arbitrary precision. We verify the accuracy of the proposed method by numerical simulations and conclude that the growth rate of a bet-hedging population shows a nontrivial dependency on their preadaptation and proliferation delays. Contrary to the current belief, our results show that faster reactions do not, in general, increase the overall fitness of a biological population.

Epidemic processes over adaptive state-dependent networks.

In this paper we study the dynamics of epidemic processes taking place in adaptive networks of arbitrary topology. We focus our study on the adaptive susceptible-infected-susceptible (ASIS) model, where healthy individuals are allowed to temporarily cut edges connecting them to infected nodes in order to prevent the spread of the infection. In this paper we derive a closed-form expression for a lower bound on the epidemic threshold of the ASIS model in arbitrary networks with heterogeneous node and edge dynamics. For networks with homogeneous node and edge dynamics, we show that the resulting lower bound is proportional to the epidemic threshold of the standard SIS model over static networks, with a proportionality constant that depends on the adaptation rates. Furthermore, based on our results, we propose an efficient algorithm to optimally tune the adaptation rates in order to eradicate epidemic outbreaks in arbitrary networks. We confirm the tightness of the proposed lower bounds with several numerical simulations and compare our optimal adaptation rates with popular centrality measures.

Central-part laryngectomy is a useful and less invasive surgical procedure for resolution of intractable aspiration.

A novel narrow-field laryngectomy procedure known as central-part laryngectomy (CPL) for less invasive laryngeal diversion in patients with intractable aspiration is introduced. We conducted retrospective case reviews of 15 patients who underwent CPL. In this procedure, an area of the glottis including the mid-part of the thyroid cartilage and cricoid cartilage is removed to separate the digestive tract from the air way. The lateral part of the thyroid cartilage, the entire hypopharyngeal mucosa and epiglottis are preserved. The superior laryngeal vessels and nerve are not invaded. All fifteen patients were relieved of aspiration without major complications. In good accordance with cutting of the cricopharyngeal muscles and removal of the cricoid cartilage, postoperative videofluoroscopy demonstrated smooth passages of barium. Ten of 12 patients who had hoped to resume oral food intake became able to do so after CPL and two others also achieved partial oral deglutition. CPL is a useful procedure for treatment of intractable aspiration and offers considerable advantages over other laryngotracheal diversion procedures from the view point of oral food intake.

Acquired idiopathic laryngomalacia treated by laser supraglottic laryngoplasty.

Laryngomalacia is the most common cause of stridor in neonates and infants, where the soft cartilages and tissues surrounding the upper larynx collapse inward during respiration. On the other hand, acquired idiopathic laryngomalacia in adults is quite rare, but should be borne in mind for differential diagnosis of upper airway distress. Allergic factors may cause airway distress, but have not been highlighted previously as the background of laryngomalacia. In this report, we describe two patients with acquired idiopathic laryngomalacia with reference to allergic rhinitis and high serum levels of immunoglobulin E. The first patient was a 16-year-old female who presented with inspiratory stridor and dyspnea due to attachment between the epiglottis and bilateral arytenoids, and the second patient was an 18-year-old male who also presented with inspiratory stridor due to attachment between the epiglottis and posterior pharyngeal wall. The respiratory function of both patients was within the normal range but the inspiratory stridor interfered with daily life. Laryngomicrosurgery was performed in both patients using a CO2 laser to remove the arytenoid mucosa in the first patient, and to remove the tip of the epiglottis in the second. Both patients were followed up while receiving oral anti-allergic agents. Laser supraglottic laryngoplasty to remove the vibrating excess tissue was effective for resolving the symptoms. However, recurrence occurred three times in the first patient, and inferior turbinotomy to improve nasal respiration was useful for diminishing the symptoms.

Isolated juvenile xanthogranuloma in the larynx of a three-year-old child.

Juvenile xanthogranuloma (JXG) is a benign manifestation of non-Langerhans cell histiocytosis characterized by yellowish cutaneous nodules. Its occurrence in the larynx is very rare, but laryngeal JXG may cause severe respiratory distress. We report a patient with isolated laryngeal JXG treated by laryngomicrosurgery, and this is the first report of JXG extending to vocal fold. A 3-year-old girl presented with hoarseness and inspiration stridor. A bulky tumor was found in right glottic to subglottic region. Subtotal resection of the tumor was carried out by laryngomicrosurgery, and airway distress was diminished after the operation. In pathological examination, the resected specimen showed proliferation of histiocytic cells and spindle cells with Touton giant cells that are characterized by polynuclei or wreath nuclei and are known to appear in JXG but not in LCH. Immunohistochemistry of histiocytic cell markers demonstrated positivity for CD68, lysozyme, alpha1-anti-chymotrypsin, factor XIIIa and vimentin, and negativity for CD1a and S-100, leading to diagnosis of JXG, but not LCH. The patient was thus expected with benign prognosis, and additional resection of the tumor including vocal fold was not indicated in the initial treatment. Six weeks later, the JXG recurred and a second procedure using CO2 laser was needed. The tumor did not re-grow thereafter, and there was no residual voice handicap. Because of its favorable prognosis and tendency for spontaneous regression, JXG in the larynx needs to be considered carefully with regard to whether reduction surgery and/or tracheotomy are necessary, and thus precise diagnosis is required.

Osseous hamartoma arising from the eustachian tube.

A fairly quite rare case of osseous tumor arising from the Eustachian tube (ET) is described. A 56-year-old man presented with a smooth bulky mass in the nasopharynx and secretory otitis media in the right ear. Computed tomography and magnetic resonance imaging indicated a solid tumor-like region occupying the nasopharynx with apparent extension to the right ET. Transnasal endoscopic surgery demonstrated that the tumor had originated from the ET, and the tumor was partially removed in the area where it had expanded into the nasopharynx. The pathological diagnosis was an osseous hamartoma consisting of bony tissue, fat cells and fibroblasts. To our knowledge, this is the first reported case of osseous hamartoma arising from the ET in the world literature. The patient presented symptoms of nasal obstruction and unilateral aural fullness. Reduction surgery and tympanostomy tube insertion were useful for accurate diagnosis and resolution of the symptoms.

Involvement of pterygoid venous plexus in patulous eustachian tube symptoms.

CONCLUSIONS: The pterygoid venous plexus (PVP) is an important factor in the mechanism of eustachian tube (ET) closure under conditions that can cause increased venous pressure in the head, such as during neck compression and postural change from the sitting/standing to the recumbent position. OBJECTIVES: The symptoms of patulous ET are usually improved by neck compression or postural change (from sitting/standing to recumbent position). Venous congestion around the ET and/or gravitational change may be involved in the changing degree of symptoms, but its mechanism is not understood. This study investigated whether the PVP is involved. MATERIALS AND METHODS: The dimensions of soft tissues surrounding ET were measured on magnetic resonance images before and after neck compression. RESULTS: The lateral pterygoid muscle became enlarged after neck compression. Simultaneously, the volume of venous plexus observed between the medial pterygoid muscle and tensor veli palatini muscle was increased. Such enlargement was probably due to blood pooling in the PVP, resulting in protrusion of the ET anterior wall to the luminal side, and decreased ET patency.

Three-dimensional computed tomography imaging in the sitting position for the diagnosis of patulous eustachian tube.

OBJECTIVE: Computed tomography (CT) in the sitting position was useful for detecting patulous Eustachian tube (ET). STUDY DESIGN: Retrospective. SETTING: Tertiary referral center. PATIENTS: Eighty-seven patients divided into two groups. The patulous ET group consisted of 111 ears of 67 patients with patulous ET. The control group consisted of 30 ears of 20 patients without symptoms characteristic of patulous ET or abnormal findings in ET function tests. MAIN OUTCOME MEASURES: CT was performed under the resting condition and during Valsalva maneuver (Valsalva condition). The multiplanar reconstruction technique was used to reconstruct 1-mm-thick gapless images parallel to and perpendicular to the ET long axis. The open tubal distance (OTD) and average ET-gram were examined. RESULTS: The OTD was significantly longer in the patulous ET group than in the control group under both resting and Valsalva conditions (both p < 0.001). The OTD was also significantly longer under the Valsalva condition than under the resting condition in both groups (p < 0.01 in the patulous ET group, p < 0.001 in the control group). The average ET-gram showed an occlusive zone in the cartilaginous portion medial to the isthmus under both the resting and Valsalva conditions in the control group (n = 30). However, the occlusive zone could not be observed under either the resting or Valsalva conditions in the patulous ET group (n = 111). Completely patent (open) ET was observed with continuous hyperlucency from the pharyngeal to the tympanic orifices in 88 of 111 patients in the patulous ET group, but in none of the control group, indicative of 100% specificity. CONCLUSION: Computed tomography in the sitting position employing Valsalva maneuver is useful for the diagnosis of patulous ET.

Neuromagnetic evaluation of binaural unmasking.

Binaural unmasking refers to the improvement in intelligibility under conditions of masking when a tone is presented out of phase rather than in phase. In the present study, binaural unmasking was evaluated using auditory-evoked magnetoencephalography (MEG) in eight healthy right-handed volunteers (7 males and 1 female, mean age 25.9 years). Peak latency and amplitude of the N1m response to tone bursts of 250 Hz (n = 8), 1000 Hz (n = 3), and 4000 Hz (n = 3) were measured under S0N0 (binaural phase difference was zero radian (in phase) for both stimulus sound and masker noise) and SpiN0 (binaural phase difference was pi radian (out of phase) for stimulus sound and zero radian for masker noise) conditions. The level of tone bursts was swept by 5 or 10 dB steps from the level of 20 dB above the psychophysical threshold under the S0N0 condition until no significant auditory-evoked field could be observed. Identical background noise was presented to both ears continuously at 50 dB SPL. N1m responses to stimuli at or above the psychophysical threshold were found bilaterally in all subjects except one who had only right hemispheric N1m. N1m response for the SpiN0 stimulus had larger amplitude and shorter latency than that for the S0N0 stimulus in each hemisphere and at each sound level. Neuromagnetic binaural unmasking was greatest around the threshold level, corresponding to psychophysical binaural unmasking; became smaller with greater stimuli, indicating the suprathreshold unmasking effect; and disappeared at around 15-20 dB above the threshold. Psychophysical binaural unmasking can be quantitatively evaluated by MEG in the auditory cortex level of the bilateral hemispheres.

Modified binaural pitch-matching test for the assessment of diplacusis.

Diplacusis is defined as the phenomenon of hearing the same tone at different pitches in the two ears. Although binaural pitch-matching using method-of-adjustment has been employed in most studies, it is sometimes hard for subjects with impaired hearing to judge 'equal pitch' as one frequency. To resolve this problem. a modified pitch-matching test, in which the relation of pitch sensation between the two ears was assessed as a matched frequency 'range' using the randomized maximum likelihood sequential procedure, was developed. Eight subjects with unilaterally impaired hearing, as well as eight normal subjects, were examined to evaluate this new test procedure. In the present method, matched frequency is assessed as a frequency range, in which subjects cannot judge whether the pitch of the signal in one ear is higher or lower than that in the opposite ear. This method appeared to be useful for assessing the characteristics of diplacusis in subjects with impaired hearing as well as in normal subjects.

Effects of contralateral noise on the measurement of auditory threshold.

It is well known that sound presented in the contralateral ear can elicit the activity of the olivocochlear (OC) efferent. In the present study, the effects of the addition of contralateral noise on the psychophysical measurements of auditory thresholds were investigated in human subjects with normal hearing. The results obtained in the present study indicate that the addition of contralateral noise at a level of only 20 or 30 dB sound pressure level (SPL) may cause a significant elevation of the auditory threshold in the mid-frequency area (usually 2-3 dB). When the level of contralateral noise was elevated, the elevation of the auditory threshold tended to be larger and the affected frequency area became wider. Although other factors that elevate the auditory thresholds, such as cross-talk effects and the acoustic reflex of the middle ear muscles, may be involved in the above-mentioned paradigm, especially when higher levels of contralateral noise are used, it is important to know the degree of OC-mediated threshold elevation in usual audiometric measurement.

Effect of iC3b binding to immune complexes upon the phagocytic response of human neutrophils: synergistic functions between Fc gamma R and CR3.

We compared the phagocytosis of immune complexes (IC) and iC3b-opsonized derivatives (iC3b-IC) by human neutrophils. The phagocytosis of iC3b-IC via Fc gamma R and CR3 was much greater than that of IC via Fc gamma R alone. Adding ethanol to the cells decreased iC3b-IC phagocytosis to that of IC, which was not affected by these reagents, suggesting that the enhanced phagocytosis is attributable to CR3-mediated phospholipase D activation. The IC phagocytosis was inhibited more effectively by anti-Fc gamma IIIB, whereas the iC3b-IC phagocytosis was partly inhibited only by anti-Fc gamma RII. The main Fc gamma R might differ in IC and iC3b-IC phagocytosis.