Objective To explore the frequency domain characteristics of pedestrian head dynamic response in vehicle collisions and investigate the correlation between frequency domain parameters and time domain injury criteria.Methods Finite element modelling based on human body model was used to simulate the process of pedestrian head-vehicle impacts,and the wavelet packet signal analysis method was employed to obtain the frequency domain response of pedestrian head in the simulations.Results The head energy under impacts at the bonnet area was mainly dispersed in the 0-300 Hz frequency band,while the head energy under impacts at the windshield area was mainly concentrated in the 0-5 Hz frequency band.The peak energy of frequency band for pedestrian head generally increased with the increase of linear and rotational speed,and the influence of rotational speed on the peak energy of frequency band was more significant when the linear speed was higher.The linear correlation R2 between the peak energy of the head frequency band caused by the collision between the bonnet and windshield area and the time-domain criterion for skull injury were 0.85 and 0.61,respectively.But their correlation with the time-domain indicators for brain injury evaluation was relatively low(R2＜0.5).Conclusions The frequency domain response characteristics of pedestrian heads are affected by collision speed and location.The peak energy of the frequency band can potentially characterize the risk of skull injury,but the frequency band and concentration of the peak energy in the frequency band are not related to the risk of head injury.This study can provide references for the evaluation of head blunt injury combined with time-frequency response.

Objective To explore the frequency domain characteristics of pedestrian head dynamic response in vehicle collisions and investigate the correlation between frequency domain parameters and time domain injury criteria.Methods Finite element modelling based on human body model was used to simulate the process of pedestrian head-vehicle impacts,and the wavelet packet signal analysis method was employed to obtain the frequency domain response of pedestrian head in the simulations.Results The head energy under impacts at the bonnet area was mainly dispersed in the 0-300 Hz frequency band,while the head energy under impacts at the windshield area was mainly concentrated in the 0-5 Hz frequency band.The peak energy of frequency band for pedestrian head generally increased with the increase of linear and rotational speed,and the influence of rotational speed on the peak energy of frequency band was more significant when the linear speed was higher.The linear correlation R2 between the peak energy of the head frequency band caused by the collision between the bonnet and windshield area and the time-domain criterion for skull injury were 0.85 and 0.61,respectively.But their correlation with the time-domain indicators for brain injury evaluation was relatively low(R2＜0.5).Conclusions The frequency domain response characteristics of pedestrian heads are affected by collision speed and location.The peak energy of the frequency band can potentially characterize the risk of skull injury,but the frequency band and concentration of the peak energy in the frequency band are not related to the risk of head injury.This study can provide references for the evaluation of head blunt injury combined with time-frequency response.

Objective:To compare 2 modalities of Kirschner pin fixation for severely displaced (Campbell type Ⅱ) juxta-epiphyseal fracture of the proximal phalanx in children.Methods:A retrospective study was conducted to analyze the clinical data of 69 children with severely displaced (Campbell type Ⅱ) juxta-epiphyseal fracture of the proximal phalanx who had been treated at Department of Orthopaedics, Shenzhen Children's Hospital from January 2018 to December 2020. Clinical data: 41 boys and 28 girls; (7.6±3.2) years in age; 34 left hands and 35 right hands affected; 4 thumbs, 4 middle fingers, 5 ring fingers, and 56 little fingers injured. The patients were divided into 2 groups according to surgical modalities. Group A (35 fingers in 35 cases) was treated by closed reduction, longitudinal intramedullary fixation with a single Kirschner pin, and external plaster fixation while group B (34 fingers in 34 cases) by closed reduction, crossing fixation with 2 Kirschner pins, and external plaster fixation. The 2 groups were compared in terms of preoperative fracture angulation, operation time, postoperative fracture angulation, hospitalization days, and postoperative functional recovery.Results:There was no statistically significant difference in the preoperative general data between the 2 groups, indicating comparability ( P>0.05). All fractures got united after 3 to 6 weeks. There was no statistically significant difference between the 2 groups in terms of preoperative fracture angulation, operation time, or postoperative fracture angulation ( P>0.05). The hospitalization days in group A were significantly shorter than that in group B ( P<0.05). Fifty children (24 cases in group A and 26 cases in group B) were followed up for (54.3±10.5) months. By the trial criteria for upper limb functional evaluation of the Hand Surgery Society, the hand function was evaluated at the last follow-up as excellent in 24 cases in group A, giving an excellent rate of 100% (24/24), and as excellent in 26 cases in group B, giving an excellent rate of 100% (26/26) too, showing no significant difference between the 2 groups ( P<0.05). No postoperative complications such as Kirschner wire breakage, needle tract infection, significant angular deformity, rotational deformity, or bone bridge formation occurred in any of the patients. Conclusion:For children with severely displaced (Campbell type Ⅱ) juxta-epiphyseal fracture of the proximal phalanx, longitudinal intramedullary fixation with a single Kirschner pin and crossing fixation with 2 Kirschner pins may achieve comparable efficacy in terms of fracture stability and function, but the former may result in shorter hospitalization days.

OBJECTIVE: To study the preparation and properties of the hyaluronic acid (HA)/α-calcium sulfate hemihydrate (α-CSH)/β-tricalcium phosphate (β-TCP) material (hereinafter referred to as composite material). METHODS: Firstly, the α-CSH was prepared from calcium sulfate dihydrate by hydrothermal method, and the β-TCP was prepared by wet reaction of soluble calcium salt and phosphate. Secondly, the α-CSH and β-TCP were mixed in different proportions (10∶0, 9∶1, 8∶2, 7∶3, 5∶5, and 3∶7), and then mixed with HA solutions with concentrations of 0.1%, 0.25%, 0.5%, 1.0%, and 2.0%, respectively, at a liquid-solid ratio of 0.30 and 0.35 respectively to prepare HA/α-CSH/ β-TCP composite material. The α-CSH/β-TCP composite material prepared with α-CSH, β-TCP, and deionized water was used as the control. The composite material was analyzed by scanning electron microscope, X-ray diffraction analysis, initial/final setting time, degradation, compressive strength, dispersion, injectability, and cytotoxicity. RESULTS: The HA/α-CSH/β-TCP composite material was prepared successfully. The composite material has rough surface, densely packed irregular block particles and strip particles, and microporous structures, with the pore size mainly between 5 and 15 μm. When the content of β-TCP increased, the initial/final setting time of composite material increased, the degradation rate decreased, and the compressive strength showed a trend of first increasing and then weakening; there were significant differences between the composite materials with different α-CSH/β-TCP proportion ( P<0.05). Adding HA improved the injectable property of the composite material, and it showed an increasing trend with the increase of concentration ( P<0.05), but it has no obvious effect on the setting time of composite material ( P>0.05). The cytotoxicity level of HA/α-CSH/β-TCP composite material ranged from 0 to 1, without cytotoxicity. CONCLUSION The HA/α-CSH/β-TCP composite materials have good biocompatibility. Theoretically, it can meet the clinical needs of bone defect repairing, and may be a new artificial bone material with potential clinical application prospect.
Calcium Phosphates ; Bone and Bones ; Phosphates

Objective To establish a valid human head-neck model and ballistic helmet model, and analyze biomechanical responses of the cervical spine under bullet impacts on ballistic helmet with different weights. Methods A uniformly distributed weight of 2 kg was applied on the helmet (1.24 kg), and bullet impacts from frontal, lateral and crown directions at the speed of 450 m/s were considered to obtain the mechanical response of human vertebrae. Results The stress of the cervical spine was significantly higher than that of the skull under bullet impacts, and the stress of C3 segment was the largest, indicating that the cervical spine was more vulnerable than the head during bullet impacts under the protection of ballistic helmet. When the weight of helmet attachment was not considered, the maximum stress of the cervical spine under lateral impact was 2.58% higher than that under frontal and crown impacts. The frontal impact led to the greatest damage to the head, with an increase of 59.4% in head stress. When the weight of helmet attachment was considered, a lager helmet weight would cause a more serious spine injure. When the helmet weight was increased from 1.24 kg to 3.24 kg, the crown impact led to the greatest damage to the cervical spine, with an increase of 12.98% in cervical stress compared with impacts from other directions. Conclusions Lightweight should be considered in the design of ballistic helmet, and the research findings provide scientific references for the design of ballistic helmet.

The observation statistics suggested that the haemolymph melanization speed of larvae became fast and the growth inhibition of Escherichia coli was strong as the quantities of feeding on mulberry leaves increased. The RT-PCR result showed that the mRNA expressions of melanin biosynthesis enzyme BmTan, BmPo-1, BmYellow-f and BmDdc were high in the haemolyph of 5 L 3 d larvae. The qPCR analysis showed Bmtan, Bmddc, Bmyellow, Bmebony and Bmblack, especially Bmddc expression were significantly higher in black disease larvae than in normal larvae. Compared with control, Ddc inhibitors drastically inhibited the lipopolysaccharide-induced haemolymph melanization. In addition, the content of Dopa and Dopamine markedly rose after E. coli injection. These indicated that haemolymph melanization was linked to immune defenses and Bmddc may play a role in melanization response of haemolymph immune in silkworm.
Animals ; Bombyx ; enzymology ; genetics ; microbiology ; Escherichia coli ; Genes, Insect ; Hemolymph ; chemistry ; Larva ; Melanins ; biosynthesis

Objective To investigate the value of KIM-1 and NGAL in predicting the early diabetes nephropathy(DN).Meth-ods 132 cases of type 1 and type 2 diabetic patients were recruited in this study,patients were divided into four groups based on the urine albumin/creatinine and serum creatinine levels,as follows:normal albuminuria group (45 cases),mi-croalbuminuria group (36 cases),clinical albuminuria group (30 cases),renal failure group (21 cases),65 healthy subjects were recruited as control group.Urinary KIM-1 and NGAL levels were measured by enzyme linked immunosorbent assay (ELISA).Results With the progress of DN,urinary KIM-1 and NGAL levels gradually increased (P<0.05),the urinary KIM-1/Ucr level was positively correlated with ACR (r=0.822,P<0.01),and the urinary NGAL/Ucr was positively cor-related with ACR (r=0.842,P<0.01).Conclusion The urinary KIM-1 and NGAL level can predict the occurrence of ear-ly DN,and also monitor the progression of DN.

OBJECTIVETo investigate the predictors of local recurrence and survival in primary retroperitoneal leiomyosarcoma (PRLS).

METHODSA retrospective analysis was conducted on 46 cases of PRLS between August 2006 and April 2012. There were 9 male and 37 female patients, and they were 30-79 year old (median 49 year old). Kaplan-Meier estimations and Cox regression analyses were performed.

RESULTSThe tumor size were 5-36 cm, and 29 cases (63.1%) of this group was more than 10 cm. Local 3- and 5-year control rates after complete resection were 47% and 30%. FNCLCC (Fédération Nationale des Centres de Lutte Contre le Cancer) grading (RR = 3.10, 95%CI: 1.59-6.04), gender (RR = 5.30, 95%CI: 1.64-17.13) and blood loss (RR = 3.12, 95%CI: 1.28-7.60) were independent prognostic factor of local recurrence in multivariable analysis (P < 0.05). The 5-year disease-free survival rates after complete resection of PRLS was 26%; and the 5-year disease-specific survival (DSS) rates after complete resection was 48%. The median DSS was 60 months in negative margin of resection and 50 months in positive margin. However, by multivariate analysis, only FNCLCC grading was significant independent predictors of DSS (RR = 2.01, 95%CI: 1.16-3.49, P = 0.013).

CONCLUSIONSGender, FNCLCC grading and blood loss were independent prognostic factor of local recurrence. The disease-specific survival in PRLS varied significantly according to FNCLCC grading.

Adult ; Aged ; Female ; Follow-Up Studies ; Humans ; Kaplan-Meier Estimate ; Leiomyosarcoma ; pathology ; Male ; Middle Aged ; Neoplasm Recurrence, Local ; pathology ; Prognosis ; Retroperitoneal Neoplasms ; pathology ; Retrospective Studies ; Survival Rate

Objective Radiation can cause multiple damages to tissues and organs.This study aimed to explore the protec-tive effect of Ganoderma lucidum polysaccharides ( GLPs) against the 60 Co-γray radiation injury in mice and provide an experimental basis for the clinical use of GLPs. Methods One hundred mice were randomly divided into five groups of equal number: normal control, gavage control, radiation control, high-dose GLPs, and low-dose GLPs.Models of radiation injury were made in the mice by whole-body exposure to 60 Co-γrays.Three days before and after mod-eling, the animals in the high-dose and low-dose GLPs groups were given GLPs intragastrically at the dose of 100 and 50 mg/kg respec-tively, once daily for 14 days.Then the 30 day survival rate and sur-vival time of the model mice were recorded and the changes in the pe-ripheral blood index, spleen index, and serum superoxide dismutase( SOD) activity were observed. Results GLPs significantly increased the 30-day survival rate and the mean survival time of the mouse models (P<0.05), decreased the reduction of WBC count in the peripheral blood, and shortened the time of WBC restoration ( P<0.05 ) .Furthermore, GLPs obviously improved the spleen index and SOD activity of the Co-γray irradiated animals. Conclusion GLPs, with a significant anti-radiation effect, can effectively raise the survival rate of the mice exposed to a lethal dose of 60 Co-γrays, reduce radiation injury to WBC and platelets, and increase the activity of SOD in irradiated mice.

Objective To describe the evolution of oculomotor nerve paresis (ONP) after endovascular packing of posterior communicating artery aneurysms (PcomA) to prospectively evaluate the effect of mecobalamine treatment on ONP prospective recovery.Methods A total of 56 patients with ONP attributable to PcomA,treated with coils in our hospital from July 2007 to January 2013,were enrolled in a randomized,controlled open study,and 55 of them got follow up;embolization+mecobalamine treatment was performed in 28 and embolization treatment was in 27.The degrees of ONP were recorded one year after treatment.Results All patients succeeded in one year follow-up; 31 patients (56.4％) achieved complete resolution of ONP,19 (34.5％) partial improvement and 5 (9.1％) no changes.The complete recovery rate in the embolization+mecobalamine treatment group was 71.4％ (20/28) and that in the embolization treatment group was 40.7％ (11/27),with statistically significant differences (P＜0.05).Conclusion Endovascular treatment is highly efficacious in treating ONP-inducing PcomA and mecobalamine treatment can promote the recovery of oculomotor nerve palsy after embolism.