• Journal of International Academy of Physical Therapy Research
• /
• v.10 no.2
• /
• pp.1763-1767
• /
• 2019

Background: Although previous researches have developed interventions for neck problems, headache, and temporomandibular disorder in patients with forward head posture (FHP), changes in masticatory muscle tone or stiffness as FHP worsening have not been investigated. Objective: To examine changes in masticatory muscle tone and stiffness through craniovertebral angle (CVA). Design: Cross sectional study Methods: The subjects were 21 healthy males with normal head posture. Three CVA were established for posture measurement in which the bilateral anterior temporal and masseter muscles were measured during the subjects maintained a series of postures. Results: The Right masseter muscle significantly increased in stiffness with advancing FHP (p < 0.05). No significant changes were observed in the muscle tone or stiffness of any other masticatory muscles, and no significant differences were found in bilateral masticatory muscle tone or stiffness in each measurement posture. Conclusions: This study suggests that the increased stiffness of the right masseter muscle as the FHP worsened requires consideration in physical therapy assessment and intervention.

• Physical Therapy Korea
• /
• v.26 no.2
• /
• pp.61-68
• /
• 2019

Background: Forward head posture (FHP) is a postural alignment of the cervical vertebrae that leads to increased gravitational load on cervical segmental motions. The overhead arm lift test assesses the ability to actively dissociate and control low cervical flexion and move the shoulders through overhead flexion. Objects: The purpose of this study was to explore muscle activities in the upper trapezius (UT), serratus anterior (SA), sternocleidomastoid (SCM), and lower trapezius (LT) alongside changes in head position during the overhead arm lift test in individuals with FHP. Methods: Fifteen subjects with forward head posture and fifteen subjects with normal subjcects were enrolled in this study. The patients performed the overhead arm lift test, and muscle activities of the UT, SCM, SA, and LT were measured using surface electromyography and by evaluating changes in head position. Independent t-tests were used to detect significant differences between the two groups and Cohen's d was calculated to measure the size of the mean difference between the groups. Results: The FHP group demonstrated significantly increased muscle activity of the UT ($32.46{\pm}7.64$), SCM ($12.79{\pm}4.01$), and LT ($45.65{\pm}10.52$) and significantly decreased activity in the SA ($26.65{\pm}6.15$) than the normal group. The change in head position was significantly higher in the FHP group ($6.66{\pm}2.08$) than the normal group. Effect sizes for all parameters assessed were large between the two groups. Conclusion: The subjects with excessive FHP displayed were unable to fix their heads in position during the overhead arm lift test. The overhead arm lift test can thus be used in clinical settings to confirm control of the neck in these subjects.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.06a
• /
• pp.24-33
• /
• 2000

The effect of particulate contamination on friction and wear between a negative-pressure picoslider / tri-pad nanoslider and laser-textured disk was studied. Particles of different concentration were injected at the head-disk interface consisting of disks with various textures and slider types at different speed. Durability increased and coefficient of friction decreased as the disk speed increased in a contaminated environment. Frictional characteristics and durability in the data zone were better for those of the laser-textured zone. It was also found that durability of head-disk interface (HDI)decreased as the particle concentration increased. The interface durability with a picoslider was better than that with a nanoslider at any condition in a contaminated environment. Based on the test results, mechanisms were proposed to explain the reasons why durability with a picoslider was superior to that with a nanoslider.

• Tribology and Lubricants
• /
• v.16 no.6
• /
• pp.469-476
• /
• 2000

The effect of particulate contamination on the friction and wear between a negative-pressure picoslider/tri-pad nanoslider and laser-textured disk was studied. Particles of different concentration were injected at the head-disk interface consisting of disks with various textures and slider types at different speed. Durability increased and coefficient of friction decreased as the disk speed increased in a contaminated environment. Frictional characteristics and durability in the data Bone were better than those in the laser-textured zone. It was also found that durability of head-disk interface (HDI) decreased as the particle concentration increased. The interface durability with a picoslider was better than that with a nanoslider at any condition in a contaminated environment. Based on the test results, mechanisms were proposed to explain the reasons why durability with a picoslider was superior to that with a nanoslider.

• Journal of Korean Academy of Nursing
• /
• v.19 no.2
• /
• pp.212-222
• /
• 1989

When the head nurse who is pivotal in the nursing service administration of the hospital performs efficiently as a first-line manager, the effectiveness of the nursing unit, which includes the quality of nursing care, the jab satisfaction of staff members, and the cohesiveness of staff members is increased. With this point of view in mind, the researcher carried out a study to determine the actual work (the content of the work, the work process, the role of the head nurse, the activity media, and the purpose of the work) of the head nurse in a university hospital in Korea. In addition, this study was also carried out for the purpose of preparing an ideal model for the work of the head nurse. The research subjects were 39 head nurses. This included all the head nurses in two university hospitals except those who were working in outpatient care, operating rooms, central supply, nursing administration, in-service education and emergency care. Data were collected from September 24th to October 21th, 1987 and April 4th to 12th, 1988. A work activity record on which the head nurse recorded directly in a chronological narrative form, was used as the research instrument. The 234 work activity records, 39 head nurse's continuous recording over 6 days(from Monday to Saturday) were collected and analysed. The results were as follows ; 1. With regard to the work content for the total daily work of the head nurse, 45.2% of the activities were managerial activities but 58.1% of the head nurse' s time was spent in direct patient care. 2. With regard to the work process of the head nurse, specifically the location, the size and membership of groups contacted, the results were as follows : 1) Of the total daily work activities 92.4% were carried out in the nursing unit and this occupied 84.5% of total daily work time. Direct patient care was generally performed on the nursing unit and managerial work was performed in other areas. 2) Of the total daily work activities, 73% was with one or more persons and 51.2% of total daily work time was spent in groups. 3) A total of 51 persons, working in different capacities were contacted. These included 21 persons giving patient care, 19 persons working in nursing unit management, and 7 persons working in human resource management. 3. With regard to the head nurse's role in work activity, 53.3% of total daily work activities involved the informational role, 26.9%, the interpersonal role and 19.9%, the decisional role. With regard to time, 57.7% was spent in the informational role, 23.9%, in the interpersonal role and 18.3%, in the decisional role. When the head nurse performed managerial work, she gave nearly equal emphasis to all three roles when she gave direct patient care the informational role was increased. 4. With regard to the activity media, the number of unscheduled activities accounted for 27.1% of the activities, scheduled activities, 24.3%, desk work activity, 22.1%, rounds, 12.5% and telephone calls, made or received, 14.0%. In daily total work time managerial work related to desk work and scheduled activities were high, ranging from 29.8% to 29.9% but for direct patient care time, scheduled activities and unscheduled activities were high, ranging from 23.6％ to 35.3%. 5. With regard to the purpose of the work performed, 54.4% of the total daily work was concerned with the team and 41.4% was concerned with the agency. The managerial work was concerned mainly with the team and the direct patient care was concerned mainly with the patient. When the frequency of an activity and time were compared no significant difference was found between the days for which the work was recorded for any of the variables : the work content, the work process, the work role, the activity media and purpose of the work. On the basis of this study the following are proposed as an ideal model for head nurse work in Korea : The managerial work should be increased to 70%. The decisional role activities should be increased to 40%. Twenty percent of the work activity should be allocated to agency, community and profession. It is believed that this model for the head nurse's work can contribute to guidelines for job description development. Finally, educational programs, organizational and structural devices, and administrative support are needed for the proper function of the head nurse in this proposed model.

• Korean Journal of Plant Resources
• /
• v.14 no.1
• /
• pp.84-88
• /
• 2001

The growth of leaves in field-grown head lettuce(cv. Urake) was compared after conventional application of N-P-K fertilizer or after application of various dilutions of livestock waste solution. Plants treated with livestock waste solution diluted 25 times (Ef. 25) or 50 times (Ef. 50) had greater growth than that for any other treatment. The number of leaves was greater with Ef. 25 than that with other treatments, although the increase was not statistically significant. Total head yield increased by fertigation with livestock waste solution compared to yield resulting from conventional fertilization. Plant tissue weight was increased according to the increase in concentration of applied livestock waste solution. The soil chemical properties, pH, electrical conductivity, $NH_4^+-N$, NO$_3$-N, available P exchangeable Ca and Mg, all increased with the increased application of livestock waste solution. In conclusion, fertigation of the dilute livestock waste solution on the range of Ef. 25 to Ef. 50 could improve yield and quality in head lettuce.

• Journal of Radiation Protection and Research
• /
• v.10 no.1
• /
• pp.29-40
• /
• 1985

The objectives of present study is to investigate genetic damage of radiation in mammalian male germ cell and. to establish available screening method for determining genetic hazard by radiation. Several methods were employed to measure the genetic damage of radiation as follows: Sperm head counts, frequency occurrence of sperm with abnormal head shape, fertility, activity of LDH-X, and the induction of unscheduled DNA synthesis (U.D.S.) in male mouse were performed with the passing of time after irradiation by making use of the sequence of event that occurs during spermatogenesis. Sperm head counts and activity of LDH-X in testes were gradually reduced by increased radiation dose and with the passing of the time after irradiation. Frequency occurrence of sperm with abnormal head shape, sterile period, and the induction of unscheduled DNA synthesis were increased by increased radiation dose. It is suggested that since germ cell is a direct reflection of genetic complement, the use of male germ cell is rapid and convenient method for measuring genetic damage by radiation.

• Radiation Oncology Journal
• /
• v.38 no.2
• /
• pp.138-147
• /
• 2020

Purpose: To evaluate the dosimetric variations in patients of head and neck cancer treated with definitive or adjuvant radiotherapy using optimized non-coplanar (ncVMAT) beams with coplanar (cVMAT) beams using volumetric arc therapy. Materials and Methods: Twenty-two patients of head and neck cancer that had received radiotherapy using VMAT in our department were retrospectively analyzed. Each of the patients was planned using coplanar and non-coplanar orientations using an optimized couch angle and fluences. We analyzed the Conformity Index (C_IRTOG), Dose Homogeneity Index (DHI), Heterogeneity Index (HI_RTOG), low dose volume, target and organs-at-risk coverage in both the plans without changing planning optimization parameters. Results: The prescription dose ranged from 60 Gy to 70 Gy. Using ncVMAT, C_IRTOG, DHI and HI_RTOG, and tumor coverage (ID_95%) had improved, low dose spillage volume in the body V_5Gy was increased and V_10Gy was reduced. Integral dose and intensity-modulated radiation therapy factor had increased in ncVMAT. In the case of non-coplanar beam arrangements, maximum dose (D_max) of right and left humeral head were reduced significantly whereas apex of the right and left lung mean dose were increased. Conclusion: The use of ncVMAT produced better target coverage and sparing of the shoulder and soft tissue of the neck as well as the critical organ compared with the cVMAT in patients of head and neck malignancy.

• Journal of Auto-vehicle Safety Association
• /
• v.4 no.2
• /
• pp.22-26
• /
• 2012

Prasad and Mertz published head injury risk curves for skull fracture and for Abbreviated Injury Scale (AIS) ${\geq}4$ brain injury due to forehead impacts based on the 15 ms HIC criterion. KNCAP adopted the HIC36 criterion for the male dummy and the HIC15 criterion for the female dummy. In this paper, it was studied that which of the HIC15 and HIC36 was more effective for the male dummy head injury evaluation. The frontal US-NCAP data for the 7 vehicles from the NHTSA test database were used to evaluate the head injuries. In the case of using the HIC15 and evaluation range 250~700, the discrimination of the rating for the occupant head injury was increased.

• Journal of the Korean Society of Safety
• /
• v.19 no.2
• /
• pp.34-40
• /
• 2004

This paper presents an analysis of SAR(Specific Absorption Rate) distribution characteristics in a head model using FDTD(Finite Difference Time Domain). In this study human head was modelled in four elements-layered structure, consisting of skin, fat, skull and brain. To calculate the electromagnetic fields wihtin the head model, FDTD method was used. In the FDTD method, the electromagnetic wave is analyzed by solving a Maxwell's equations repeatedly. For the calculation, distance between power source and head model increased by 10[m]. Power density and incident electric field intensity were calculated. Based on the incident electric field, the program which calaculated internal electric fields intensity and SAR calculation of the head model were developed. The results of developed program using FDTD were compared with those of a commericial programs, which showed the availability and usefulness of the suggested scheme in this paper.