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Species categorical authentication of accelerants has traditionally relied on fire debris analysis. To explore a novel method for identifying the accelerants species, four commonly used accelerants for arson were loaded onto different substrates and ignited at different locations. The entire combustion process was recorded and flame characteristics were analyzed. The results showed that the probability density function (PDF) of flame apex angle counts within a certain period after ignition can be used to distinguish accelerant species, and this method is not affected by accelerant loading amount, ignition location, and substrate, demonstrating strong stability and universality, while the temporal variation of flame area and the value obtained by dividing half of the flame width by the flame height (tangent of flame cone angle) can effectively differentiate gasoline and diesel. The utilization of flame characteristics for identifying accelerants species holds significant implications for arson investigation.

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A three-dimensional finite element model is used to investigate the vibrational properties of double-walled silicon carbide nano-cones with various dimensions. The dependence of the vibrational properties of double-walled silicon carbide nano-cones on their length, apex angles and boundary conditions are evaluated. Current model consists a combination of beam and spring elements that simulates the interatomic interactions of bonding and nonbonding. The Lennard-Jones potential is employed to model the interactions between two non-bonding atoms. The fundamental frequency and mode shape of the double-walled silicon carbide nano-cones are calculated.

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The shape of the cutting blades of the abrasive grains has an influence on the material separation process in the machining zone. The paper analyzes the influence of the geometrical parameters of the abrasive grains (rake angle γ, apex angle ε, opening angle α), as well as width bz and length bb of the cutting zone on the material removal efficiency. The material removal efficiency was determined taking into account the volume of the removed material VG and the volume of lateral piles-up VR. The analyses were carried out on the basis of the results of experimental and simulations using the finite element method. The relationship between the selected geometric parameters characterizing the cutting zone and the coefficient characterizing the efficiency of the material removal process was determined. A strong influence of the opening angle α as well as the width bz and length bb of the cutting zone on the material removal process by abrasive grain was demonstrated. It was observed that the wide cutting edge, and thus the large opening angle α of the grain, reduced the size of the pile-ups and more effectively removed the chip material.

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OBJECTIVE: Although anterior compression factors and cervical alignment affect neural decompression, cervical laminoplasty may be used to achieve indirect posterior decompression. The focal apex (FA) angle of the anterior compression factor of the spine represents the degree of anterior prominence toward the spinal cord. The authors investigated the mechanism underlying the influence of FA angle and cervical alignment on spinal cord alignment (SCA) after laminoplasty, including how high-intensity signal cord change (HISCC) on preoperative T2-weighted MRI (T2-MRI) may affect neurological improvement. METHODS: We performed a retrospective study of patients who underwent laminoplasty for CSM or OPLL at two hospitals (Kanto Rosai Hospital, Kawasaki City, and Yokohama Minami Kyousai Hospital, Yokohama City, Japan) between April 2004 and March 2015. In total, 109 patients (mean age 67.3 years) with cervical compression myelopathy were included. FA angle was defined as the preoperative angle between the lines from the top of the prominence to the upper and lower adjacent vertebrae. Preoperative cervical alignment was measured between the C2 and C7 vertebrae (C2-7 angle). MRI was used to classify SCA as lordosis (type-L SCA), straight (type-S), local kyphosis (type-LK), or kyphosis (type-K). Preoperative HISCC was investigated by using T2-MRI. Neurological status was evaluated by using the Japanese Orthopaedic Association score. RESULTS: The mean preoperative FA and C2-7 angles were 32.1° and 12.4°, respectively. Preoperative SCA was type-L or type-S in 53 patients. The neurological recovery rate (NRR) was significantly higher for patients with preoperative type-L and type-S SCA (51.4% for those with type-L and 45.0% for those with type-S) than for patients with other types (35.3% for those with type-LK and 31.7% for those with type-K). Among patients with preoperative type-L or type-S SCA, 87.3% maintained SCA; however, 5/12 (41.7%) patients with a preoperative average C2-7 angle < 12.4° and an average FA angle > 32.1° had postoperative type-LK or type-K SCA. SCA changed to type-L or type-S in 13.0% of patients with preoperative type-LK or type-K SCA. Moreover, in these patients, FA angle was significantly smaller and NRR was significantly higher than in other patients in whom postoperative SCA remained type-LK or type-K. Preoperative T2-MRI showed 73 patients with HISCC (43 with type-L and type-S, and 30 with type-LK and type-K SCA) and 36 without HISCC (20 with type-L and type-S, and 16 with type-LK and type-K SCA); the NRRs of these patients were 42.6% and 41.2%, respectively. No significant differences in SCA or NRR were observed between patients with and without HISCC. CONCLUSIONS: NRR depends on preoperative SCA type; however, it is possible to change the type of SCA after laminoplasty. Preoperative FA and C2-7 angles influence change in SCA; therefore, they are important parameters for successful decompression with cervical laminoplasty.

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BACKGROUND: Rocker sole (RS) shoes have been linked to impaired postural control. However, which features of RS design affect balance is unclear. RESEARCH QUESTION: Which RS design features affect standing balance and gait stability? METHODS: This study utilized an intervention and cross-over design. Twenty healthy young adults (10 males and 10 females) participated in this study. Standing balance and gait stability were measured using a single force platform and three-dimensional motion analysis system, respectively. The experimental conditions included the control shoe and five RS shoes in the combination of apex position (%) and apex angle (degree) for RS50-95, RS60-95, RS70-95, RS60-70, and RS60-110. The main outcome measures were the area surrounding the maximal rectangular amplitude, mean path length, average displacement of the center of pressure along the lateral and anterior/posterior directions, and maximal center of pressure excursion as the standing balance and lateral margin of stability as the gait stability. Statistical analyses were conducted using a two-way split-plot analysis of variance with repeated measures (with RS design as the within-subject factor and sex as the between-subject factor) and the Bonferroni post hoc test (α = .05). RESULTS: Regarding the mean path length, RS60-70 was significantly longer than the control shoe, and it showed a significantly increased lateral margin of stability. Thus, RS60-70 was shown to affect standing balance, limit of stability, and gait stability of the frontal plane during gait. SIGNIFICANCE: These results suggest that the apex angle of the RS design feature affects standing balance and gait stability, and RS60-70 is detrimental to stability. Therefore, when RS with a small apex angle is prescribed, it is necessary to consider the patient's balance ability.

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PURPOSE: The purpose of this study was to identify the different factors that an oculoplastic surgeon should consider while practicing cosmetic or reconstructive eyebrow surgery in order to have the final patient's satisfaction. SUBJECTS AND METHODS: In an observational case series study, five photographs were taken from each of 60 females to show ideal eyebrow positioning with fingers. Eyebrow landmarks, including tarsal plate show (TPS) and eyebrow height, were measured in the ideal position. Brow apex position and brow apex angle were evaluated in the desired position of eyebrow. RESULTS: The mean desired apex angle of eyebrow was measured as 135±9 mm. In all, 48.33% of our subjects preferred a wider brow angle, 28.33% a narrower one, and 23.33% a brow angle without any change. The location of brow peak was transferred to the lateral canthus in the desired position. The ideal brow peak in the lateral canthus and between lateral canthus and lateral limbus was assigned to 33.3% and 66.6% of cases, respectively. The desired eyebrow apex angle in two age groups of our subjects (>40 years and ≤40 years) was not statistically different. CONCLUSION: Landmarks of the eyebrow and its desired position are somehow different between different studies, which may be explained by the variation in race, gender, culture, and age. As there is not any uniform rule in planning of cosmetic surgeries of eyebrow, oculoplastic surgeons should consider the difference in culture, race, age, and desire of the patients and have their surgical plans for every individual patient distinctively.