Biomedical subjects

G M Davis

Publications and source records attributed to G M Davis.

At least 19 recordsLinked to original sources

PubMed2005

Sleep and breathing on the first night after adenotonsillectomy for obstructive sleep apnea.

Adenotonsillectomy (T&A) has established effectiveness for the treatment of obstructive sleep apnea (OSA). However, more than 20% of children with OSA have respiratory compromise requiring medical intervention in the postoperative period. The reasons for this complication are not well-defined. We aimed to compare the nature and severity of sleep-disordered breathing in children with mild and severe OSA on the first night following adenotonsillectomy. Ten children were classified into groups of mild and severe OSA, based on preoperative testing. On the first night after T&A, they underwent polysomnography, including electroencephalograph, submental electromyography, bilateral electro-oculograms, monitoring of respiratory movements, heart rate, ECG, and oxygen saturation. Sleep-disordered breathing was assessed by the apnea-hypopnea index, the SaO(2) nadir, and the desaturation index, including dips in saturation below 90% (DI(90)). Sleep quality was assessed by sleep efficiency, time spent in each sleep state, and respiratory arousal index. Obstructive events occurred postoperatively in all children, but were more frequent in those with severe OSA preoperatively: the median (interquartile range) mixed/obstructive apnea/hypopnea indicies were 6.9 (2.2-9.8) events/hr and 21.5 (15.1-112.1) events/hr for the mild OSA group and the severe OSA group, respectively (P = 0.009). Obstructive events were the major cause of desaturation during sleep postoperatively. Sleep quality was severely disrupted in both groups, with reductions in both slow-wave sleep and rapid eye movement sleep. In conclusion, despite removal of obstructing lymphoid tissue, upper airway obstruction occurred on the first postoperative night in children with OSA. This study is the first to demonstrate the mechanism of respiratory compromise after adenotonsillectomy, a common postoperative complication in children with severe OSA.

Adenoids↗

PubMed2003

Acoustic reflectance of pharyngeal structures in children.

The aim of this study was to examine whether Eccovision Reflectance Pharyngometer could assess the anatomical structure of the upper airway in young children. Secondary aims were to assess changes in pharyngeal volume in children with tonsillar (Group A, n=13) and adenoidal hypertrophy (Group B, n=17) at pre- and post- surgical procedures, respectively and further compare them to children who underwent myringotomy (Control Group C, n=10). In all 40 children (aged 3-9 years, median 6 years) enrolled in this pilot prospective study, six recordings (equally dispersed at pre- and 3 month post- operation per subject) of the pharyngeal cavity along with demographic (age, gender), somatic (standing and sitting height, body weight, head and neck circumference) and anatomic (bimaxilliary and bregma) characteristics, were captured. No significant intra-subject variability was noted within the multiple measurements of the pharyngeal volume at pre- as well as post-incision (ANOVA, P>0.1) in all groups. However, in Group A there was a marked increase from pre- to post-pharyngeal volumes in males (P=0.007), which was not observed in females (P=0.13). In Group B pharyngeal volumes decreased from pre- to post- in both males (P=0.87) and females (P=0.34). On the contrary, in Group C there was no change in pharyngeal volumes. These findings contradicted the visual evaluation of the size of the removed tonsillar and/or adenoidal mass in the first two groups and thus suggested that Eccovision Pharyngometer does not reliably assess pharyngeal volumes in a pediatric population.

Adenoidectomy↗

PubMed2003

Weaning infants with respiratory syncytial virus from mechanical ventilation through a fuzzy-logic controller.

We have previously developed a fuzzy logic controller for weaning adults with chronic obstructive pulmonary disease using pressure support ventilation (PSV). We used the core of our fuzzy logic-based weaning platform and further developed parametrizable components for weaning newborns of differing body size and disease-state. The controller was validated on neonates recovering from congenital heart disease (CHD) while receiving synchronous intermittent mandatory ventilation (SIMV). We wished to compare the efficacy of this controller versus the bedside weaning protocol in children with respiratory syncytial virus pneumonitis/bronchiolitis (RSV) in the pediatric intensive care unit (PICU). The fuzzy controller evaluated the "current" and "trend" weaning status of the newborn to quantitatively determine the change in the SIMV integrated ventilatory setting. For the "current" status it used heart rate (HR), respiratory rate (RR), tidal volume (VT) and oxygen saturation (SaO2), while for the "trend" status the differences of deltaRR/ deltat, deltaHR/ deltat, and deltaSaO2/ deltat recorded between two subsequent time points were utilized. The enumerated vital signs were fuzzified and then probability levels of occurrence were assigned. Individualized "golden" goals for SaO2 were set for each newborn. We retrospectively assessed the charts of 19 newborns, 113+/-128 days old, 5,546+/-2,321 gr body weight, weaning for 99+/-46 days, at 2-hour intervals. The SIMV levels proposed by the fuzzy controller were matched to those levels actually applied. In 60% of the time both values coincided. For the remaining 40%, the controller was more aggressive suggesting lower values of SIMV than the applied ones. The Area under the SIMV curves over time was 1,969+/-1,044 for the applied vs 1,886+/-978 for the suggested levels, respectively. The fuzzy controller adjusted for body size and disease-pattern can approximate the actual weaning course of newborns with RSV.

Female↗

PubMed2002

Effects of electrical stimulation-induced leg training on skeletal muscle adaptability in spinal cord injury.

Neuromuscular electrical stimulation has grown in popularity as a therapeutic device for training and an ambulation aid to human paralyzed muscle. Despite its current clinical use, few studies have attempted to concurrently investigate the functional and intramuscular adaptations which occur after electrical stimulation training. Six individuals with a spinal cord injury performed 10 weeks of electrical stimulation leg cycle training (30 min d(-1), 3 d week(-1)). The paralyzed vastus lateralis muscle showed significant alterations in skeletal muscle characteristics after the training, indicated by an improvement in total work output (52-112 kJ; P < 0.05), an increase in fiber cross-sectional area (18 to 41 x 10(2) microm(2); P < 0.05), a reduction in the percentage of type IIX fibers (75% to 12%; P < 0.05), a decrease in myosin heavy chain IIx (68% to 44%; P < 0.05), an increase in capillary density (2-3.5 capillaries around fiber; P < 0.05) and increases in activity levels of citrate synthase (7-16 mU mg(-1) protein) and hexokinase (1.2-2.4 mU mg(-1) protein). This study showed that 10 weeks of electrical stimulation training of human paralyzed muscle induces concurrent improvements in functional capacity and oxidative metabolism.

Adaptation, Physiological↗

PubMed2002

External power output changes during prolonged cycling with electrical stimulation.

This study analysed external power output and physiologic responses in 5 individuals with paraplegia during 40 minutes of electrical stimulation leg cycle exercise. Cycling was performed on a motor-driven isokinetic ergometer that enabled precise determinations of power output. Electrical stimulation was increased to 120-140 mA within the first 5 minutes and remained constant thereafter. Power output increased to 10.7 +/- 3.0 W after 2 minutes, dropped to 5.3 +/- 1.8 W after 6 minutes and subsequently recovered to 8.2 +/- 2.2 and 6.1 +/- 2.3 W after 19.5 and 40 minutes, respectively. Oxygen consumption increased to 0.47 +/- 0.09 l/min after 6 minutes and declined during the second half of the exercise bout. Gross mechanical efficiency after 19.5 minutes was elevated compared with the value after 6 minutes. Heart rate was significantly increased at the end of the trial. The time-dependent variability of power output and physiological responses question the concept of steady state for this form of exercise.

Adult↗

PubMed2002

Fuzzy logic controller for weaning neonates from mechanical ventilation.

Weaning from mechanical ventilation is the gradual detachment from any ventilatory support till normal spontaneous breathing can be fully resumed. To date, we have developed a fuzzy logic controller for weaning COPD adults using pressure support ventilation (PS). However, adults and newborns differ in the pathophysiology of lung disease. We therefore used our fuzzy logic-based weaning platform to develop modularized components for weaning newborns with lung disease. Our controller uses the heart rate (HR), respiratory rate (RR), tidal volume (VT) and oxygen saturation (SaO2) and their trends deltaHR/deltat, deltaVT/deltat and deltaSaO2/deltat to evaluate, respectively, the Current and Trend weaning status of the newborn. Through appropriate fuzzification of these vital signs, Current and Trend weaning status can quantitatively determine the increase/decrease in the synchronized intermittent mandatory ventilation (SIMV) setting. The post-operative weaning courses of 10 newborns, 82+/-162 days old, were assessed at 2-hour intervals for 68+/-39 days. The SIMV levels, proposed by our algorithm, were matched to those levels actually applied. For 60% of the time both values coincided. For the remaining 40%, our algorithm suggested lower SIMV support than what was applied. The Area Under the Curve for integrated ventilatory support over time was 1203+/-846 for standard ventilatory strategies and 1152+/-802 for fuzzy controller. This suggests that the algorithm, approximates the actual weaning progression, and may advocate a more aggressive strategy. Moreover, the core of the fuzzy controller facilitates adaptation for body size and diversified disease patterns and sets the premises as an infant-weaning tool.

Area Under Curve↗

PubMed2001

Cardiovascular responses during arm exercise and orthostatic challenge in individuals with paraplegia.

In this study the cardiorespiratory responses during arm crank ergometry (ACE) performed at two submaximal intensities (30% and 50% of heart rate reserve) and moderate orthostatic challenge were investigated in individuals with paraplegia (PARA). The effect of concurrent electrical stimulation (ES)-induced leg muscle contractions on the responses to ACE during orthostatic challenge was also investigated. Eight PARA (T5-T12) and eight able-bodied (AB) individuals participated in this study, however only seven subjects from each group completed all tests and were used in subsequent data analyses. Oxygen uptake (VO2), heart rate (fc), stroke volume (SV) and cardiac output (Qc) were assessed during (1) ACE alone, (2) ACE and lower body negative pressure (ACE + LBNP), and, in PARA only, (3) ACE + LBNP with ES (ACE + LBNP+ ES). In both PARA and AB, ACE + LBNP decreased SV (by 13-18% and 20-23%, respectively) and increased fc (by 13-15% and 16%, respectively) compared to ACE alone. The decrease in SV was greater in AB than in PARA (significant group x trial interaction; both ACE intensities pooled), but there was no difference in the magnitude of increase in fc between groups. ES-induced leg muscle contractions increased SV (up to 16%) but did not change VO2 or Qc. The smaller reduction in SV from ACE to ACE + LBNP in PARA may indicate a mechanism by which adequate central blood volume can be maintained in the face of orthostatic challenge, despite the absence of supraspinal control below the spinal cord lesion. With ES-induced leg muscle contractions, the decrease in SV, which occurred during ACE + LBNP, was reversed via reactivation of the lower limb muscle pump and augmented venous return.

Adult↗

PubMed2001

Evolutionary relationships between trematodes and snails emphasizing schistosomes and paragonimids.

Snails and digeneans have been associated for at least 200 million years. Their inter-relationships over such a time-span must have been complex and varied. Few studies have attempted to explore these relationships in the light of knowledge of the phylogeny of both host and parasite groups. Here we focus on two important families of digeneans, the Schistosomatidae and the Paragonimidae, for which molecular phylogenies are available. We investigate the types of evolutionary relationships between host and parasite, operating at different phylogenetic depths, that might explain current host specificity and distributions of both associates. Both families of parasites utilise a number of highly diverged gastropod families, indicating that host extensions have featured in their histories. However, schistosomatids and paragonimids show different patterns of association with their snail hosts. As befits the apparently more ancient group, schistosomatids utilise snails from across a wide phylogenetic range within the Gastropoda. The genus Schistosoma itself has experienced one long-range host switch between pulmonates and caenogastropods. By contrast, paragonimids are restricted to two superfamilies of caenogastropods. Despite these differences, modern schistosomatid species appear to be more host specific than are paragonimids and host additions, at the level of host family, are far less common among species of schistosomatids than among paragonimids. Some species of Paragonimus exhibit remarkably low levels of host specificity, with different populations utilising snails of different families. Existing knowledge relating to the phenomenon will be presented in the context of phylogenies of schistosomatids, paragonimids, and their snail hosts. Discussion focuses on the usefulness of current theories of snail-digenean coevolution for interpreting these findings. In the past, much emphasis has been placed on the idea that digeneans engage in a one-to-one arms race with their snail host. We consider that phylogenetic tracking rather than an arms-race relationship might be a common alternative. Not being bound by the restrictions imposed by an arms race, some digeneans might be able to extend to new host species more easily than the literature suggests. Switches into related host taxa are most likely. However, ecologically equivalent but unrelated gastropod hosts may also be exploited. Given the right ecological setting, digeneans are able to switch across considerable phylogenetic distances. Examples from the Paragonimidae and Schistosomatidae are given.

Animals↗

PubMed2001

Quantifying pulmonary hypertension in ventilated infants with bronchiolitis: a pilot study.

OBJECTIVE: To determine whether previously well infants ventilated for bronchiolitis have sufficiently elevated pulmonary artery pressures (PAP) to warrant a trial of inhaled nitric oxide (iNO) therapy. METHODS: Consecutive infants mechanically ventilated for bronchiolitis were offered Doppler echocardiography between 24 and 72 h after intubation. Patients were divided into those with normal PAP, mild, moderate or severe pulmonary hypertension. Patients with at least moderate pulmonary hypertension (systolic PAP > 30 mmHg and > 50% of systemic systolic arterial pressure) were offered a 60 min trial of iNO therapy at a concentration of 20 ppm and repeat echocardiography. RESULTS: Six infants (four preterm, two term) were studied at a mean corrected age of 13 weeks (4, 24). Respiratory syncytial virus was confirmed on immunofluorescence of nasal secretions in five of six subjects (84%). Echocardiography was performed (mean, 5.5 days) (95%CI 3.8-7.3) after the onset of symptoms. All patients had structurally normal hearts. Four patients had mild pulmonary artery hypertension and two had normal pulmonary artery pressures. None of the patients qualified for iNO therapy. The mean (range) duration of intubation was 14 days (9-19) and the duration of hospitalization was 28 days (14-42). All patients recovered. CONCLUSION: Significant pulmonary hypertension should not be presumed in previously well preterm and term infants ventilated for bronchiolitis.

Bronchiolitis↗

PubMed2001

Schistosomiasis in the People's Republic of China: prospects and challenges for the 21st century.

Schistosomiasis japonica is a serious communicable disease and a major disease risk for more than 30 million people living in the tropical and subtropical zones of China. Infection remains a major public health concern despite 45 years of intensive control efforts. It is estimated that 865,000 people and 100,250 bovines are today infected in the provinces where the disease is endemic, and its transmission continues. Unlike the other schistosome species known to infect humans, the oriental schistosome, Schistosoma japonicum, is a true zoonotic organism, with a range of mammalian reservoirs, making control efforts extremely difficult. Clinical features of schistosomiasis range from fever, headache, and lethargy to severe fibro-obstructive pathology leading to portal hypertension, ascites, and hepatosplenomegaly, which can cause premature death. Infected children are stunted and have cognitive defects impairing memory and learning ability. Current control programs are heavily based on community chemotherapy with a single dose of the drug praziquantel, but vaccines (for use in bovines and humans) in combination with other control strategies are needed to make elimination of the disease possible. In this article, we provide an overview of the biology, epidemiology, clinical features, and prospects for control of oriental schistosomiasis in the People's Republic of China.

Animals↗

PubMed2001

A baseline study on the importance of bovines for human Schistosoma japonicum infection around Poyang Lake, China.

We hypothesize that bovine infections are responsible for the persistence of human schistosomiasis transmission in the Yangtze marshlands of China. To test this hypothesis, we are carrying out a comparative intervention among four administrative villages in the Poyang Lake region, Jiangxi Province, two of which are experimental and two are control. The primary design involves treating, at the onset of the study, all the inhabitants in all four villages with praziquantel and all the bovines in two villages (the experimental or intervention villages). Following treatment, rates of reinfection in people of all villages, and in bovines in the experimental villages, will be assessed as will the ongoing prevalence of infection in bovines in the control villages. Before treatment, the prevalence and intensity of infection among humans and bovines was ascertained in the four villages. Our study design and baseline information are presented here, along with a description of the ecology of the study villages.

Adolescent↗

PubMed2001

[Preliminary study on cytochrome C oxidase 1 gene of Oncomelania hupensis from Miao River area in Hubei province].

OBJECTIVE: To study the mitochondrial cytochrome C oxidase 1(CO1) gene of Oncomelania snails from Miao River area in Hubei Province. METHODS: Oncomelania snails were collected from Miao River area, including upstream and downstream. Genomic DNA was extracted from the tissue of the snail. PCR was used to amplify a fragment of the CO1 gene. Sequences of the CO1 fragment were determined directly from the purified PCR products by an automated sequencer. Sequences for each individual were assembled and edited using ESEE 3.0 s. A distance matrix was computed using program DNADISt of PHYLIP(3.57). Unrooted maximum likelihood trees were calculated from program FITCH. RESULTS: The amplified CO1 gene of the snail was a fragment of 638 bp in length. Sequence analysis showed that the accumulated variable sites were significant different between upstream and downstream populations, being 29 and 46, respectively. From the number of variable sites in the gene, snails in this area were roughly separated into two groups. Each of them was a mixture of both upstream and downstream snails. Same haplotypes were confirmed to be present among the collected sites along the river. From the distance matrix of sequence divergence, the population upstream vs downstream differed by 0.0221 +/- 0.0105. CONCLUSION: There were more variation in downstream population than that in upstream. Gene flow was identified in these populations. The phylogenetic trees suggest the existence of two groups, but all of them belong to 0. h. hupensis.

Animals↗

PubMed2001

Observer error and prediction of outcome--grading of head injury based on computerised tomography.

OBJECTIVE: To measure inter-observer error of a recently reported computerised tomography scoring system and to assess the ability of the scoring system to predict outcome in head injury patients. METHODS: Two radiologists independently graded all CT scans performed during the admission of all head injured patients. They were blinded to the clinical condition of the patient. Patients were followed up at 12 months and given a Glasgow outcome score. Outcomes were matched to the 2 independent assessments done on the first CT scan for each patient. RESULTS: A total of 123 head injury patients were studied. For the diffuse injury categories, there were 410 gradings made. Of these, 32% differed by at least one category. Where at least one of the radiologists identified non-evacuated mass lesions there were 148 gradings. Of these, one radiologist reported an un-evacuated mass lesion in 47%, which was not reported by the other. The first CT scan was evaluated on 119 patients. Using the Chi-Squared test, the diffuse injury IV category was the only one to show a strong relationship with outcome as measured by the Glasgow outcome score. CONCLUSIONS: The prediction of outcome for head injury patients based on CT scans has significant shortcomings. In our study, there was significant variation in grading by experienced radiologists. The separate categories were also poor predictors of outcome at 12 months except for diffuse injury IV. The classification of mass lesions needs modification to be useful.

Journal Article↗

PubMed2000

Oncomelania hupensis (Gastropoda: rissooidea) in eastern China: molecular phylogeny, population structure, and ecology.

The rissooidean snail genus Oncomelania is of medical interest as various taxa are hosts for the human blood fluke Schistosoma and the lung fluke Paragonimus; because of close co-evolved host-parasite-relationships, snail diversity may reflect parasite diversity. There is a considerable amount of confusion regarding the identity of smooth- and ribbed-shelled populations of Oncomelania hupensis in eastern China. We therefore studied the genetic variation, population structure, phylogenetic relationships and ecology of five smooth- and five ribbed-shelled populations in Hubei, Hunan, Anhui, Zhejiang, and Jiangsu provinces. Based on sequencing data of a fragment of the mitochondrial gene for cytochrome oxidase I from 80 individuals, we found little genetic variability within the ingroup-individuals studied here (average pi=0.01922). Moreover, within the ingroup, smooth-shelled individuals cluster together with ribbed-shelled individuals. We therefore consider all smooth- and ribbed-shelled populations of Oncomelania throughout the lower Yangtze River basin to belong to the subspecies O. hupensis hupensis. Our data indicate that ribbing in O. h. hupensis is associated with the annual floods of the Yangtze River. The greatest haplotype (d(H)) and nucleotide diversities (pi) are found in aggregates of ribbed-shelled snails along areas of the Yangtze River drainage subject to flooding. In areas not affected by flooding, the shells are smooth and genetic diversity decreases significantly.

Animals↗

PubMed2000

Effects of electrical stimulation leg training during the acute phase of spinal cord injury: a pilot study.

Four individuals with a spinal cord injury underwent 16 weeks of isometric electrical stimulation training to both legs for 60 min, five times per week during the first 5 months after injury, while two SCI individuals remained untrained. A baseline biopsy sample of the vastus lateralis muscle was obtained within 1 month of injury, and another biopsy sample was taken after a further 16 weeks. The untrained, paralyzed skeletal muscle displayed a reduction in (1) type I fibers (from 50% to 9%), (2) myosin heavy chain (MHC) I (from 27% to 6%), and (3) fiber cross-sectional area of type I, type IIA and type IIX fibers (-62%, -68%, and -55%, respectively) when compared to the baseline sample of muscle taken within 1 month of injury. In contrast, the trained group showed smaller alterations in type I fibers (from 49% to 40%) and MHC I composition (from 39% to 25%), while fiber cross-sectional area was similar to baseline levels for type I, type IIA and type IIX fibers (-3%, -8%, and -4%, respectively). In conclusion, electrical stimulation training can largely prevent the adverse effects of a spinal cord injury upon paralyzed human skeletal muscle if applied soon after the injury.

Adolescent↗

PubMed2000

The Preschool Respiratory Assessment Measure (PRAM): a responsive index of acute asthma severity.

OBJECTIVE: To elaborate and validate a Preschool Respiratory Assessment Measure (PRAM) that would accurately reflect the severity of airway obstruction and the response to treatment in young patients with asthma. STUDY DESIGN: A prospective cohort study was performed in 217 children aged 3 to 6 years who presented to a pediatric emergency department with acute asthma. Respiratory resistance measured by forced oscillation served as a gold standard. Children were randomized to either the test group, in which multivariate analyses were performed to elaborate the PRAM, or the validation group, in which the characteristics of the PRAM were tested. RESULTS: For the test group (N = 145), the best multivariate model contained 5 variables: wheezing, air entry, contraction of scalenes, suprasternal retraction, and oxygen saturation. In the validation group (N = 72), the PRAM correlated substantially with the change in resistance (r = 0.58) but modestly with the % predicted resistance measured before (r = 0.22) and after bronchodilation (r = 0.36). A change of 3 (95% CI: 2.2, 3.0) indicated a clinically important change. CONCLUSIONS: PRAM appears to be a responsive but moderately discriminative tool for assessing acute asthma severity. This measure, designed for preschool-aged children, has been validated against a concurrent measure of lung function.

Acute Disease↗

PubMed2000

Carotid baroreflex control of heart rate and blood pressure during ES leg cycling in paraplegics.

This study investigated control of heart rate (HR) and mean arterial pressure (MAP) at rest and during electrical stimulation (ES) leg cycling exercise (LCE) in paraplegics (Para). Seven men with complete spinal lesions (T(5)-T(11)) and six able-bodied (AB) men participated in this study. Beat-to-beat changes in HR and MAP were recorded during carotid sinus perturbation. Carotid baroreflex function curves were derived at rest and during ES-LCE for Para and during voluntary cycling (Vol) for AB. From rest to ES-LCE, oxygen uptake (VO(2)) increased (by 0.43 l/min) and HR rose (by 11 beats/min), yet MAP remained unchanged. In AB, Vol increased VO(2) (by 0.53 l/min), HR (by 22 beats/min), and MAP (by 8 mmHg). ES-LCE did not alter the carotid sinus pressure (CSP)-MAP relationship, but it displaced the CSP-HR relationship upward relative to rest. No rightward shift was observed during ES-LCE. Vol by AB produced an upward and rightward displacement of the CSP-MAP and CSP-HR relationships relative to rest. These findings suggested that the carotid sinus baroreflex was not reset during ES-LCE in Para.

Adult↗

PubMed2000

Treating internal resorption using a syringeable composite resin.

BACKGROUND: Internal resorption is a pathological process initiated within the pulp space with the loss of dentin. It often is described as an oval shaped enlargement of the root canal space and usually is asymptomatic and detectable by routine radiographs. Treatment of internal resorption has included several materials--gutta-percha, zinc oxide eugenol and amalgam alloy. These materials do not provide strength to the tooth structure. CASE DESCRIPTION: A 29-year-old woman was referred to a dental clinic for treatment of a large internal resorptive defect in the coronal and middle one-third of the maxillary left central incisor root with no apparent periapical pathosis, as well as a large periapical radiolucency at the apex of the maxillary left lateral incisor that was associated with a necrotic pulp. The authors used a dual-cure syringable composite resin in conjunction with a bonding agent within the defect to treat it. CLINICAL IMPLICATIONS: This technique seals the dentinal tubules and strengthens the remaining tooth structure. It also improves the outcome of resorptive defects and reduces operators' chair time.

Adult↗