Comparison of the observer, single-frame video and computer vision hand activity levels.

Observer, manual single-frame video, and automated computer vision measures of the Hand Activity Level (HAL) were compared. HAL can be measured three ways: (1) observer rating (HALO), (2) calculated from single-frame multimedia video task analysis for measuring frequency (F) and duty cycle (D) (HALF), or (3) from automated computer vision (HALC). This study analysed videos collected from three prospective cohort studies to ascertain HALO, HALF, and HALC for 419 industrial videos. Although the differences for the three methods were relatively small on average (<1), they were statistically significant (p < .001). A difference between the HALC and HALF ratings within ±1 point on the HAL scale was the most consistent, where more than two thirds (68%) of all the cases were within that range and had a linear regression through the mean coefficient of 1.03 (R2 = 0.89). The results suggest that the computer vision methodology yields comparable results as single-frame video analysis.Practitioner summary: The ACGIH Hand Activity Level (HAL) was obtained for 419 industrial tasks using three methods: observation, calculated using single-frame video analysis and computer vision. The computer vision methodology produced results that were comparable to single-frame video analysis.

The Handling of Oxalate in the Body and the Origin of Oxalate in Calcium Oxalate Stones.

Urolithiasis is one of the most common urologic diseases in industrialized societies. More than 80% of renal stones are composed of calcium oxalate, and small changes in urinary oxalate concentrations affect the risk of stone formation. Elucidation of the source of oxalate and its mechanism of transport is crucial for understanding the etiology of urolithiasis. Sources of oxalate can be both endogenous and exogenous. With regard to oxalate transport, tests were carried out to prove the function of solute-linked carrier 4 (SLC4) and SLC26. The molecular mechanism of urolithiasis caused by SLC4 and SLC26 is still unclear. The growing number of studies on the molecular physiology of SLC4 and SLC26, together with knockout genetic mouse model experiments, suggest that SLC4 and SLC26 may be a contributing element to urolithiasis. This review summarizes recent research on the sources of oxalate and characterization of the oxalate transport ionic exchangers SLC4 and SLC26, with an emphasis on different physiological defects in knockout mouse models including kidney stone formation. Furthermore, SLC4 and SLC26 exchangers provide new insight into urolithiasis and may be a novel therapeutic target for modification of urinary oxalate excretion.

Predicting Sagittal Plane Lifting Postures From Image Bounding Box Dimensions.

OBJECTIVE: A method for automatically classifying lifting postures from simple features in video recordings was developed and tested. We explored if an "elastic" rectangular bounding box, drawn tightly around the subject, can be used for classifying standing, stooping, and squatting at the lift origin and destination. BACKGROUND: Current marker-less video tracking methods depend on a priori skeletal human models, which are prone to error from poor illumination, obstructions, and difficulty placing cameras in the field. Robust computer vision algorithms based on spatiotemporal features were previously applied for evaluating repetitive motion tasks, exertion frequency, and duty cycle. METHODS: Mannequin poses were systematically generated using the Michigan 3DSSPP software for a wide range of hand locations and lifting postures. The stature-normalized height and width of a bounding box were measured in the sagittal plane and when rotated horizontally by 30°. After randomly ordering the data, a classification and regression tree algorithm was trained to classify the lifting postures. RESULTS: The resulting tree had four levels and four splits, misclassifying 0.36% training-set cases. The algorithm was tested using 30 video clips of industrial lifting tasks, misclassifying 3.33% test-set cases. The sensitivity and specificity, respectively, were 100.0% and 100.0% for squatting, 90.0% and 100.0% for stooping, and 100.0% and 95.0% for standing. CONCLUSIONS: The tree classification algorithm is capable of classifying lifting postures based only on dimensions of bounding boxes. APPLICATIONS: It is anticipated that this practical algorithm can be implemented on handheld devices such as a smartphone, making it readily accessible to practitioners.

The Effect of Daily Fluid Management and Beverages Consumption on the Risk of Bladder Cancer: A Meta-analysis of Observational Study.

Epidemiological studies have evaluated the risk of bladder cancer (BCa) in relation to total fluid intake, as well as specific type of beverages consumption, with controversial results. The aim of this study was to further explore the potential relationship by conducting a meta-analysis. Fifty-four articles involving more than 43,000 BCa patients were included in this meta-analysis. A positive, though not statistically significant, association was found between total fluid intake and risk of BCa comparing the highest with lowest intake (SRRE: 1.16, 95%CI: 1.00-1.36). By conducting dose-response meta-analysis, we found that each 500 ml/day increase in total fluid intake was associated with 3.3% increased risk of BCa (RR: 1.03, 95%CI: 1.00-1.07). Pronounced increase in risk of BCa was detected when total fluid intake was more than 3000 ml/day. Meta-analyses of specific type of beverages showed increasing intake of coffee (RR: 1.03, 95%CI: 1.02-1.05) were risk factors for BCa. On the contrary, increasing intake of milk appeared to be a potential protective factor for BCa (RR: 0.90, 95%CI: 0.83-0.98). The risk of BCa was not significantly related to intake of water (RR: 1.01, 95%CI: 0.98-1.03), alcohol (RR: 1.01, 95%CI: 0.97-1.05), tea (RR: 1.01, 95%CI: 0.97-1.05) and soft drinks (RR: 1.04, 95%CI: 0.96-1.11).

An investigation into four different sit-stand workstation use schedules.

Twelve office workers participated in a study investigating effects of four sit/stand schedules (90-min sit/30-min stand, 80/40, 105/15, and 60/60) via several objective and subjective measures (muscle fatigue, foot swelling, spinal shrinkage, and self-reported discomfort). Results showed that there were no significant differences in shoulder and low back static muscle activities between sitting and standing. Muscle fatigue was developed during workday under all schedules. The longest standing schedule seemed to have a tendency of reducing muscle fatigue. None of the schedules helped or worsened foot swelling and spinal shrinkage. More active break-time activities seemed reducing muscle fatigue and foot swelling. While the self-reported bodily discomfort levels were generally low, the preferred schedules among the participants were varied, although the least standing schedule was the least preferred. We may conclude that effects of using sit-stand workstation to improve musculoskeletal health may be limited but promoting more active break-time activities can help. Practitioner Summary: Sit-stand workstations are used to reduce work-related musculoskeletal disorders. This study shows that office workers prefer sit/stand durations in the range between 1:1 and 3:1. Longer standing may have the potential to reduce muscle fatigue. However, active break-time activities may be more effective in reducing muscle fatigue and foot swelling.

Normative data on the one-handed static pull strength of a Chinese population and a comparison with American data.

We assess the one-handed static pull strength of a Chinese population and compare it to that of an American sample. Fifty men and 50 women in five age groups were asked to exert their maximum one-handed pull strength in three pulling directions (across, front and side) and from four pulling heights (61 cm, 76 cm, waist height and above-shoulder height). The results showed that women had less pull strength than men under all of the conditions tested. The front and side pulling resulted in the greatest pull strength, with a decrease detected when the pulling height was increased. The American sample exhibited greater strength than the Chinese. Body mass and men's handgrip force were also associated with the pull strength. These variables should be taken into account in the development of tasks related to one-handed pulling. Practitioner summary: In this paper, we report a laboratory-based experiment conducted to assess the one-handed static pull strength of a Chinese population and compare the results with those of an American population. The variables associated with pull strength included gender, pulling direction, pulling height, race, body mass and men's handgrip force.

Synthesis of novel lipophilic N-substituted norcantharimide derivatives and evaluation of their anticancer activities.

This research attempted to study the effect of lipophilicity on the anticancer activity of N-substituted norcantharimide derivatives. Twenty-three compounds were synthesized and their cytotoxicities against five human cancer cell lines studied. The lipophilicity of each derivative was altered by its substituent, an alkyl, alkyloxy, terpenyl or terpenyloxy group at the N-position of norcantharimide. Further, among all synthesized derivatives studied, the compounds N-farnesyloxy-7-oxabicyclo[2.2.1]heptane-2,3-dicarboximide (9), and N-farnesyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboximide (18), have shown the highest cytotoxicity, anti-proliferative and apoptotic effect against human liver carcinoma HepG2 cell lines, yet displayed no significant cytotoxic effect on normal murine embryonic liver BNL CL.2 cells. Their overall performance led us to believe that these two compounds might be potential candidates for anticancer drugs development.

Shoulder muscle fatigue development in young and older female adults during a repetitive manual task.

Age may modify the association between occupational physical demand and muscle loading, and ultimately increase the risk of musculoskeletal disorders. The goal of this study was to investigate age-related differences in shoulder muscle fatigue development during a repetitive manual task. Twenty participants in two age groups completed an 80-minute simulated low-intensity assembly task. Electromyographic (EMG) manifestation of muscle fatigue was observed in the upper trapezius, deltoid and infraspinatus muscles in both age groups, and coincided with an increase in the subjective ratings of perceived exertions. Compared with the younger group, older group showed a more monotonic decrease in EMG power frequency in the upper trapezius and deltoid muscles. However, the age-related difference in EMG amplitude was less consistent. Relative rest time of the upper trapezius muscle in the older group was less than the young group throughout the task. The observed patterns of EMG measures suggest that older participants may have disadvantages in fatigue resistance in the upper trapezius and posterior deltoid muscles during the simulated repetitive manual task.

A year-long case study of multicomponent interventions to promote physical activity in office workers: A randomized control trial.

The purpose of this study was to identify if workplace interventions, (i.e., mindfulness classes and monetary incentives for gym attendance), influenced workers' physical activity. Office-based participants were randomized into one of four intervention assignments: 1) CONTROL (no interventions) (n = 40), 2) MINDFULNESS (n = 33), 3) GYM INCENTIVE (n = 41), or 4) BOTH mindfulness and gym incentive (n = 31). Activity-tracker and self-reported metabolic expenditure and step counts were gathered between January 2020 and December 2020 whereas the eight-week long interventions were provided between January and March 2020, when the impact of COVID-19 pandemic started. While physical activity decreased during the follow-up months, percent changes of physical activity at 1-, 2-, and 9-month follow-ups compared to baseline show no significant differences between or across the four intervention assignments (p > 0.05). These results suggest that the intervention assignments had no effect on physical activity from baseline. The lack of effectiveness of these interventions on participant physical activity could be attributed to the influence of the COVID-19 pandemic, and any effects of the interventions could not outweigh the effects of the pandemic.

Work from home: Facilitators for an effective ergonomic work system.

Previous studies on Human Factors and Ergonomics (HFE) have primarily examined the impact of Work-From-Home (WFH) on worker health and well-being, yet little research has examined the optimal implementation process of WFH programs. Work systems perspective suggests that organizational policies, leadership, and psychological factors collectively influence the success of organizational change efforts. Our study explored the roles of managerial/supervisory, psychological, and organizational policy factors in facilitating the relationship between employees' HFE awareness and their acceptance and satisfaction with the WFH arrangement. Using data from 3195 knowledge workers in the US who use computers as their primary work tool and have worked from home at least one day in the past 30 days, we employed structural equation modeling to test our hypotheses. Transformational HFE leadership and employees' general self-efficacy are pivotal in implementing ergonomic WFH arrangements. The combination of employees' HFE awareness, transformational HFE leadership, and adequate levels of self-efficacy may foster positive process outcomes (e.g., readiness for WFH arrangement, workspace design satisfaction) in WFH arrangements. Efforts that are coordinated across organizational levels determine the effectiveness of organizational change.

Effect of aging on inter-joint synergies during machine-paced assembly tasks.

In recent years, uncontrolled manifold (UCM) analysis has emerged as an important method to study variability of human movements. The current study investigated the upper extremity movements during typical assembly tasks using the framework of the UCM analysis. Younger and older participants performed machine-paced assembly tasks, while the kinematics of upper extremities were recorded using a motion tracking system. The upper extremity was modeled as a 7 degrees-of-freedom system. The variance of joint angles within the UCM space (V UCM) and the variance perpendicular to the UCM space (V ORT) were analyzed. The results indicated that V UCM were not significantly different for the older and younger groups. For the older group, V ORT was significantly less than the younger group and resulted in less total variance (V TOT) and a better synergy level (Z ΔV ). Therefore, the synergies of upper extremity movement may not be impaired for machine-paced tasks as people age. While current results showed a different effect of aging on the synergies of body movement compared with one previous study, they were in line with a recently proposed theory that for natural tasks, aging people did not have impairment in the ability to organize upper extremity movement into synergies.

Shoulder joint loading and posture during medicine cart pushing task.

Excessive physical loads and awkward shoulder postures during pushing and pulling are risk factors for shoulder pain. Pushing a medicine cart is a major component of a work shift for nurses and medical assistants in hospitals and other health care facilities. A laboratory experiment was conducted to examine the effects of common factors (e.g., lane congestion, cart load stability, floor surface friction) on shoulder joint moment and shoulder elevation angle of participants during cart pushing. Participants pushed a medicine cart on straight tracks and turning around right-angle corners. Peak shoulder joint moments reached 25.1 Nm, 20.3 Nm, and 26.8 Nm for initial, transition, and turning phases of the pushing tasks, indicating that shoulder joint loading while pushing a medical cart is comparable to levels previously reported from heavy manual activities encountered in industry (e.g., garbage collection). Also, except for user experience, all other main study factors, including congestion level, cart load stability, location of transition strip, shoulder tendency, surface friction, and handedness, significantly influenced shoulder joint moment and shoulder elevation angle. The findings provide a better understanding of shoulder exposures associated with medicine cart operations and may be helpful in designing and optimizing the physical environment where medicine carts are used.

The natural angle between the hand and handle and the effect of handle orientation on wrist radial/ulnar deviation during maximal push exertions.

The purpose of this experiment was to quantify the natural angle between the hand and a handle, and to investigate three design factors: handle rotation, handle tilt and between-handle width on the natural angle as well as resultant wrist radial/ulnar deviation ('RUD') for pushing tasks. Photographs taken of the right upper limb of 31 participants (14 women and 17 men) performing maximal seated push exertions on different handles were analysed. Natural hand/handle angle and RUD were assessed. It was found that all of the three design factors significantly affected natural handle angle and wrist RUD, but participant gender did not. The natural angle between the hand and the cylindrical handle was 65 ± 7°. Wrist deviation was reduced for handles that were rotated 0° (horizontal) and at the narrow width (31 cm). Handles that were tilted forward 15° reduced radial deviation consistently (12-13°) across handle conditions. PRACTITIONER SUMMARY: Manual materials handling (MMH) tasks involving pushing have been related to increased risk of musculoskeletal injury. This study shows that handle orientation influences hand and wrist posture during pushing, and suggests that the design of push handles on carts and other MMH aids can be improved by adjusting their orientation to fit the natural interface between the hand and handle.

Physiological responses, trunk posture, and work pace in commercial building cleaning in Washington State: An observational field study.

INTRODUCTION: This study aimed to investigate whether work pace is a critical indicator for predicting a janitor's risk of work-related musculoskeletal disorders (WMSDs). METHOD: Field measurements were obtained from commercial building janitors as well as the determination of work pace. Physiological responses collected were heart rate, energy expenditure (calories), activity level (METs), steps, trunk posture. Data were obtained using direct measurements, along with a time study, which was performed by shadowing 13 janitors in Washington State. The measured values were summarized descriptively, and five of the most common janitorial tasks were compared. The relationships between work pace and the physiological response variables were determined by calculating the Pearson product-moment correlation coefficients. RESULTS: The highest average percent heart rate reserve (47.4%) was reported during restroom cleaning, while the highest activity and energy expenditure levels (3.6 METs and 217.1 calories/h) were reported for mopping. The top 90% of trunk flexion angles and the highest percentage of time in trunk flexion from 20° to 60° were recorded during restroom cleaning. Restroom cleaning showed the highest correlation between all the physiological response variables and work pace. In most of the tasks, a high work pace may have increased the degree and duration of severe trunk flexion. CONCLUSION: Overall, when several tasks were considered, the extent of physiological responses, trunk joint angles, and exposure time to awkward postures tended to increase with an increase in work pace. PRACTICAL APPLICATIONS: This study showed the feasibility of using the work pace measured from time studies as a predictive indicator of WMSDs risks. Using this information, managers may compose a schedule that can minimize WMSDs risks while considering actual work pace deviations that may impact a janitor's ability to complete assigned tasks properly within a shift.

A clinical epidemiological study on congenital ear malformation (CEM).

BACKGROUND: There is no report about the definition, classification and clinical epidemiological study of congenital ear malformation (CEM).Aims/Objectives: To investigate the definition, clinical classification and distribution of a large number of CEM cases, along with the clinical and epidemiological characteristics associated with congenital malformation of the middle and outer ear (CMMOE). MATERIAL AND METHODS: A total of 3231 cases (4714 ears) with CEM and related malformations were retrospectively analyzed, including 2,658 cases (4,064 ears) CEM and 573 cases (650 ears) preauricular fistulas and accessory ears, specifically related malformations to CEM. RESULTS: Among the 2,658 cases (4,064 ears) CEM, 64.9% cases were male and 35.1% were female. 52.9% cases with bilateral, 29.1% with right and 18.0% with left CEM. A subgroup of 1,050 cases (1,331 ears) was identified as CMMOE out of 1,090 cases (1,379 ears) microtia. In the CMMOE subgroup, 74.0% cases were male, 46.3% on the right side, 26.8% showed bilateral involvement. Out of the CMMOE with available images, there were 947 cases (1,105 ears). Additionally, related malformations including preauricular fistulas and accessory ears, were solely occured in 573 cases (650 ears), except for their occurrence simultaneously with CEM. The classification and distribution of CEM are as follows:1. 2658 cases of CEM (1) 69.9% of them were confined to the ear, including: ① the outer ear 2.6%, the middle ear 17.0% and the inner ear 32.4%, ② two parts simultaneous malformations of the outer ear, the middle ear and the inner ear 17.2%, ③ three parts simultaneous malformations of the outer ear, the middle ear and the inner ear 0.6%, (2) Multiple malformations including in CEM 29.1%; (3) syndromes related to CEM 1.0%.2. 1050 cases of CMMOE (1) 36.3% of them were confined to the middle and outer ears; (2) Multiple malformations associated with CMMOE 61.4%, including hemifacial microsomia 50.5%, accessory ears 9.8%, preauricular fistulas 9.2%, heart malformation 7.1%, and kidney malformation 2.0%; and (3) syndromes related to CMMOE 2.3%, (4) Complications of the ear 16.9%, mainly including otitis media 7.9%, outer ear canal cholesteatoma 6.3%, retroauricular abscess 1.1%, and nasal and pharyngeal complications 18.6%. The proportions of microcia grades I-Ⅴ based on the images of 1105 ears CMMOE were 5.2%, 10.5%, 74.1%, 6.9%, and 3.3%, respectively. Among the 1331 ears CMMOE, the incidence rates of outer ear canal atresia, stenosis, normal, and ossicles malformation were 86.5%, 9.9%, 3.6%, and 98.3%, respectively.Conclusion and Significance: Approximately 69.9% of CEM cases were confined to the ear itself, with the highest proportion being inner ear malformation alone. Multiple malformations were predominantly associated with CMMOE. Syndromes related to CEM were relatively rare. Among cases of microtia, 96.3% were classified as CMMOE. These cases were predominantly observed in males, right ear and exhibited characteristics such as grade III microtia, atresia of the outer ear canal, ossicles malformation, and multiple malformations. The multiple malformations frequently included hemifacial microsomia, accessory ear, preauricular fistula, as well as heart and kidney deformities. CMMOE often coexisted with ear infections, cholesteatoma, and complications in the nasal and pharyngeal regions.

The significance of masking for the poor hearing ear in pure tone audiometry.

BACKGROUND: In pure tone audiometry, when the difference of the Average Air Conduction Threshold of pure tone (AACT) between bilateral ears is more than 40 dB HL masking must be performed on the poor side, However, we found that masking also make significance difference when the binaural AACT difference (AACT-d)was less than 40 dB HL in some patients. AIMS/OBJECTIVE: Assessing the significance of masking for the poor ear in pure tone audiometry in patients with different types of deafness to obtain preoperative accurate hearing. MATERIAL AND METHODS: A comparative analysis of 163 cases (163 ears) with hearing difference between two ears was conducted, who were divided into three groups: G1 Congenital Malformation of the Middle and Outer Ear (CMMOE)as conductive deafness, 63 ears, G2 sudden deafness as sensorineural deafness, 65 ears, and G3 media otitis as conductive or mixed deafness,35 ears. AACT-d before and after the poor ear masking was analyzed under the following three conditions: (1) 0.125-8 KHz each frequency, (2) 0.5-4 KHz on average, (3) the frequencies of AACT-d ≥ 40 dB HL and <40 dB HL between the two ears before masking. If the sample data did not follow a normal distribution, the Wilcoxon rank sum test was used for comparasion of AACT, and p < 0.05 was considered statistically significant. It is clinically effective for AACT-d ≥ 15 dB HL at 1 frequency or 10 dB HL ≤ AACT-d at 2 frequencies <15 dB HL before and after masking. RESULTS: Among the three groups, (1) the comparasion of AACT-d before and after the poor ear masking for each frequency of 0.125-8 KHz and 0.5-4 KHz on average with all p < 0.05, and the AACT-d of the G1 group was the largest, with an average 0.5-4KHz of 7.5 dB HL, and the first two were 14.5 dB HL and 13.8 dB HL at 0.125 KHz and 0.25 KHz, respectively. (2) AACT-d ≥ 40 dB HL and <40 dB HL between the two ears before masking were distributed at the full frequency of 0.125-8KHz, the clinically effective rates of ≥40 dB HL groups were G1 (89.3%), G2 (45.5%) and G3 (5.3%), while those of < 40 dB HL groups were G1 (69.7%), G2 (34.4%) and G3 (31.3%), respectively. CONCLUSION AND SIGNIFICANCE: For all three groups, there was statistically significant in AACT-d before and after the poor ear masking across each frequency of 0.125-8 KHz and on average 0.5-4 KHz. The distribution of AACT-d ≥ 40 dB HL and <40 dB HL between the two ears before masking was observed throughout the full frequency range of 0.125-8 KHz. AACT-d before and after the poor ear masking showed clinical effectiveness in all three groups, with the highest effective rate observed in the G1 group and the highest AACT-d at 0.125 KHz and 0.25 KHz. Therefore, regardless of whether the AACT-d between the two ears before masking is ≥40 dB HL or <40 dB HL, the full frequency masking should be employed in three groups, especially for the G1 group of CMMOE, particularly at 0.125 KHz and 0.25 KHz.

Relationship between congenital malformation of the outer ear and hearing.

Background: There is no report on the relationship between congenital malformation of the outer ear and hearing, which makes it possible to predict the hearing level just based on microtia grades.Aims/Objectives: To investigate the correlation between two types of congenital malformation of the outer ear [microtia and Outer Ear Canal Malformation (OECM)] and hearing, as well as the interrelationship among all three variables.Material and methods: A total of 535 cases (598 ears) of congenital malformation of the middle and outer ear (CMMOE) with hearing data, out of which 319 cases (349 ears) microtia with available images and graded by I-V, 449 cases (482 ears) OECM graded by atresia, stenosis and normal, and 87 cases (87 ears) OEC atresia graded I-IV, 301 cases (301 ears) with materials of microtia, OECM and hearing at the same time were carried out correlation analysis. The Average Air-Conduction Threshold of pure tone (AACT) at 0.5-4 KHz was calculated corresponding to the ears with different malformation grades. The differences in AACT among different malformation grades, the correlation between malformation severity and AACT, as well as the relationship among microtia, OECM and AACT were analyzed. The one-way analysis of variance (ANOVA) was employed to compare the differences in AACT, Kendall's tau-b rank correlation coefficient test was used for correlation analysis. A statistical significance level of p < 0 .05 was applied.Results: Among the 349 ears with microtia, the corresponding AACT values for grades I to V were 61.6, 63.0, 69.9, 75.4, and 75.0 (dB HL), respectively. Comparing grade III to grades II or IV, both p < 0 .05. However, p > 0 .05 between grade I and II or between grade IV and V. The correlation coefficient between microtia grades and AACT r = 0.219, p < 0.05. Among the 482 ears of OECM, the distribution was as follows: 73.6% atresia, 19.1% stenosis, and 7.3% normal, the corresponding AACT values were 64.1, 61.7, and 52.5 (dB HL), respectively. Comparing normal to stenosis or atresia, both p < 0.05, while between atresia and stenosis p > 0.05. The correlation between OECM and AACT was r = 0.104, p < 0.05. The AACT values corresponding to grades I to IV of OEC atresia in the 87 ears were 59.9, 65.1, 71.1, and 64.1 (dB HL), respectively. Comparing these grades, all p > 0.05. The correlation between the degree of atresia and AACT r = 0.23, p < 0 .05. The correlation coefficients for 301 ears microtia to OECM, microtia to AACT, OECM to AACT were r = 0.339, r = 0.163 and r = 0.128 respectively, with all p < 0 .05.Conclusion and significance: There are positive correlations among the degree of microtia, degree of OECM, and AACT values for each other, and so between the degree of OEC atresia and AACT, suggesting that as the severity of microtia or OECM increased, the AACT also tended to be higher, which make it possible to predict the hearing level and the degree of OECM based on microtia grades in clinical practice. Additionally, there are significant differences in AACT values in microtia grade III to grades II or IV, OEC normal to stenosis or atresia, while no differences in microtia grade I to II and grade IV to V, OEC stenosis to atresia, and among the grades I-IV of the OEC atresia.

New strategies and methods for reconstruction of the outer ear canal (OEC).

Background: The incidence of re-stenosis or re-atresia after reconstruction of the Outer Ear Canal (OEC) in patients with Congenital Malformation of the Middle and Outer Ear (CMMOE) is very high (up to 48%), and it has been a difficult problem for otologists not being able to solve.Aims/Objectives: To explore new strategies and methods to improve re-stenosis or re-atresia after reconstruction of the OEC in patients with CMMOE.Material and Methods: According to the characteristics of reconstructed OEC (r-OEC) re-stenosis or re-atresia summarized by us, a number of new prevention strategies and methods have been proposed and related patent products have been designed, including the improvement of covering epithelium types and skin grafting methods (7 types), simulated drum ring function to prevent the formation of negative pressure in the cavity, and strengthen postoperative support to reduce skin shrinkage and bone hyperplasia. The postoperative effects of different ages and preoperative OEC malformations are statistically analyzed.Results: The incidence of re-stenosis/re-atresia is 14.3% (5/35) in the thin sectional skin of the temporal scalp overlap splicing skin grafting, which was significantly better than 45.5% (15/33) in the whole piece mosaic splicing and barrel skin grafting from the inner thin sectional thigh skin and overlay splicing other methods, including the inner thigh thin sectional skin, chest medium thick skin and subcutaneous pedicle + chest medium thick skin (p<0.05). The patent artificial drum ring and the model stent of the OEC have obvious effects. The mean operation age of postoperative atresia, stenosis, and good groups are 9.3, 13.1, and 12.5 years old, respectively. The proportion of preoperative atresia is 91.3%, 85.7%, and 57.7%, respectively. The total incidence of re-atresia and re-stenosis of r-OEC for two groups of atresia and stenosis of OEC before surgery is 40.5% (49/121) and 13.3% (8/60), respectively.Conclusions and Significance: The best result is found in overlapping the splicing thin sectional skin of the temporal scalp, combined with artificial drum ring implantation, effective support of postoperative model stent of OEC and post-pubertal surgery selection are new and effective strategies and methods to prevent re-stenosis or re-atresia of r-OEC. Atresia or stenosis of the OEC before the operation is the influence factor of the postoperative effect.

Innovated surgery incision for patients of congenital malformation of the middle and outer ear with infection (CMMOEI).

BACKGROUND: It is the challenging clinical issue of combining debridement of infected lesions and retaining the blood skin flap for auricle reconstruction in patients of Congenital Malformation of the Middle and Outer Ear with Infection (CMMOEI). AIMS/OBJECTIVES: To innovate and introduce an surgery incision to solve the challenging clinical issue of a combined debridement of infection yet retaining a well vascularized skin flap for auricle reconstruction in patients with CMMOEI. MATERIAL AND METHODS: A combined innovated incision of ear sulcus and prefabricated earlobe was used for 23 cases (23 ears) with CMMOEI, The success in the management of the encountered infections, and the short and moderate-term outcome of the innovated incision to preserve a well-vascularized skin flap for subsequent auricle reconstruction were reviewed. The 23 cases include 10 males and 13 females, aged 4-14 years (mean 8.4 years), 7 left ears and 16 right ears. 14 ears stenosis and 9 ears atresia of the outer ear canals. RESULTS: In all 23 cases, the infections were successfully cleared without recurrence or complication with 2-year follow-up. The local skin flap and its blood supply were well preserved for subsequent auricle reconstruction. CONCLUSIONS AND SIGNIFICANCE: The new incision can facilitate clearance of infection in CMOMEI patients, and preserve the retroauricular tissues for subsequent harvesting of a well-vascularized skin flap for subsequent auricle reconstruction.

The effects of joint torque, pace and work:rest ratio on powered hand tool operations.

Repetitive use of hand-held power tools is associated with work-related upper extremity musculoskeletal disorders. Using a pneumatic nutrunner, 21 men completed twelve 360 repetitive fastener-driving sessions on three joints (hard, soft and control) at slow and fast pace, and two different work:rest patterns. Handgrip force and perceived exertions were collected throughout each session. For the control joint, the mean grip force exerted was 39.6% of maximum voluntary exertion (MVE) whereas during hard and soft joint sessions it was 48.9% MVE and 56.9% MVE, respectively. Throughout each session, the grip force decreased, more while operating soft and hard joints as compared with the control joint (regression slope: -0.022 and -0.023, compared with -0.007 N/drive, respectively), suggesting considerable upper extremity muscular effort by participants during torque buildup. Fast work pace resulted in higher average grip forces by participants but a greater decrease in the force as the session progressed. Providing rest breaks reduced perceived exertions. The findings gain additional knowledge for assembly task design to possibly reduce the hand/arm injury risks for the operator. Practitioner Summary: Powered hand tools are widely used in assembly and manufacturing industries. However, the nature of their repetitive use on human operator biomechanical and perceptual responses is not fully understood. This study examined work-related risk factors such as joint torque, pace and work:rest ratios on powered hand tool performance.