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BACKGROUND: The risk factors for patellofemoral pain syndrome are still unclear and research on risk factors is gradually becoming a hot topic in order to improve the therapeutic outcome of this disease. OBJECTIVE: To investigate the relationship between lower limb alignment and patellofemoral pain syndrome in young male runners. METHODS: In the same running population, 21 patients with bilateral knee pain, 29 patients with single knee pain and 20 normal runners were collected from January 2021 to July 2022. Full-length X-ray examination of both lower limbs in standing position was performed in all subjects. The lateral distal femoral angle, medial tibial proximal angle, joint line congruence angle, hip-knee-ankle angle, and knee physical valgus angle were measured and statistically analyzed. RESULTS AND CONCLUSION: There was no significant difference in the parameters between the left and right knees in each group (P > 0.05). Compared with the normal group, no significant changes in lateral distal femoral angle, medial tibial proximal angle, joint line congruence angle, and hip-knee-ankle angle were observed in the single knee pain group and double knee pain group, while the knee physical valgus angle was significantly increased in these two groups (P < 0.05). To conclude, increased knee physical valgus angle may be a risk factor for patellofemoral pain syndrome. [ABSTRACT FROM AUTHOR]

Objective: To study and explore the clinical efficacy of improved Masquelet technique in the treatment of tibia infectious defect. A retrospective analysis was made of 21 patients with tibia infectious defect treated with improved Masquelet technique in the in our hospital from 2018.01 to 2022.01. To evaluate the clinical efficacy of Masquelet in the treatment of tibia infectious defect in the aspects of bone healing, soft tissue healing, infection control, limb function and complications. Results: A total of 21 patients were followed up for 12-36 months (mean 18.6 months) and they all achieved bone healing (3.2 +8.3 months). Bone healing was evaluated by Samantha X-ray score: 4 in 1 cases, 5 in 8 cases and 6 in 12 cases. According to PALEY score, the healing of bone defect and the functional classification of affected limb were excellent in 9 cases, good in 11 cases, fair in 1 cases and poor in 0 cases, and the excellent and good rate was 95.2% . There was no serious complication in all patients. Conclusion: The application of improved Masquelet technique in the treatment of tibia infectious defect is a simple, safe and effective method, which could be further promoted in clinic. [ABSTRACT FROM AUTHOR]

BACKGROUND: Intramedullary nail is a classical scheme for the treatment of femoral shaft fracture. Its distal aiming frame is widely used in the placement of distal locking nail, which improves the accuracy of distal locking nail placement, but its failure rate cannot be ignored. It is urgent to develop a new technology that can actualize the rapid and accurate locking of distal locking nail and reduce the X-ray radiation damage of bare-handed locking nail. OBJECTIVE: To compare the effect of place-occupying compression rod technique and bare-hand locking nail technique in distal locking nail placement of femoral intramedullary nail. METHODS: The eight model bones with the deviation of the compression rod that could not be accurately placed into the distal locking nail were divided into two groups. The place-occupying compression rod group (n=4) adopted the place-occupying compression rod technology. After drilling the hole adjacent to the original pressure rod hole, the accurate pressing rod was carried out, and then the distal locking nail placement carried on. In the bare-hand locking nail group (n=4), the technique of bare-hand nail under the supervision of C-arm was used to complete the placement of locking nail in the distal locking hole. The X-ray exposure times, nail locking time and nail placement accuracy were compared between the two groups. RESULTS AND CONCLUSION: (1) The number of X-ray exposure in the place-occupying compression rod group was significantly less than that in the bare-hand locking nail group (P < 0.05). The time of locking nail in the place-occupying compression rod group was significantly shorter than that in the bare-hand locking nail group (P < 0.05). The accuracy of nail placement in both groups was 100%. (2) The results showed that the technique of place-occupying compression rod and the technique of bare-hand locking nail could complete the placement of distal locking nail accurately, and the technique of place-occupying compression rod has the advantages of shorter operation time and less X-ray radiation compared with the technique of bare-hand locking nail. [ABSTRACT FROM AUTHOR]

Restricted by test conditions, performing spacecraft anti-multi-source X-ray ground simulation test is generally difficult. A single source X-ray numerical simulation equivalent test method is proposed. To overcome the “excessive greedy” phenomenon of the expected improvement(EI)method in the equivalent test points searching, a hierarchical EI equivalent test model is established. On this basis, by introducing quadratic terms into the improvement function, the model’s global searching ability is further improved. The anti-X-ray radiation numerical simulation test of CFRP material is subject to the object, and the hierarchical EI equivalent test model is used for equivalent test input value search. The results indicate that the hierarchical EI equivalent test model has higher search accuracy. [ABSTRACT FROM AUTHOR]

25. 4 mm diameter crystals of CeB- and three analogues doped with 0.1%, 0. 2% and 0. 5% of Sr2 + in molar ratio were grown by the vertical Bridgman method. The grown crystals were processed into 25. 4 mm diameter wafer with a thickness of 10 mm and characterized by fluorescence spectra excited by UV light and X-ray as well as multi-channel analysis with 137 Cs source. Results show that the emission bands of the crystals under X-ray excitation are slightly red-shifted by Sr2 + doping, and with the increase of Sr2 + doping content, the energy resolution of the crystals are successively improved, while the light yield are gradually reduced. The CeB- crystal doped with 0. 5% Sr2 + exhibits the best energy resolution of 3. 83% @ 662 keV. However, high Sr2 + doping also causes difficulty in crystal growth. A doping content of 0. 2% is considered appropriate with regards to both scintillation property and crystal growth availability. An encapsulated CeBr3: 0. 2% Sr crystal with dimension of ©25.4 mm X25.4 mm is obtained and the energy resolution is 3. 92% @662 keV. [ABSTRACT FROM AUTHOR]

The dislocation etch pit density (EPD) of the 2-inch diameter n-type (100) Te-GaSb single crystal grown in batches by the liquid encapsulated Czochralski (LEC) method is usually lower than 300 cm-2, reaching dislocation-free level. In this paper, the lattice perfection and subsurface damage of this GaSb single crystal polished substrate were characterized by X-ray rocking curve and reciprocal space map (RSM). The results show that after chemical mechanical polishing with optimized process conditions, the surface of GaSb single crystal substrate is atomically smooth, and there is no subsurface damaged layer. High-quality type-II superlattice epitaxial materials can be stably grown on this substrate by molecular beam epitaxy and exhibit excellent infrared detection performance. On this basis, the internal relationship between the physical properties, growth preparation and substrate processing conditions of GaSb substrate materials was comprehensively analyzed. [ABSTRACT FROM AUTHOR]

Objective To explore the correlation between the severity of emphysema and osteoporosis in patients with chronic obstructive pulmonary disease (COPD). Methods The chest CT and lumbar vertebral dual X-ray absorptiometry (DXA) examinations were retrospectively analyzed in 120 patients with COPD and 60 healthy control subjects. Severity of emphysema was categorized according to the percentage of low attenuation area (LAA%) as mild, moderate, or severe. The bone mineral density (BMD) T values of lumbar vertebrae were compared between COPD and control, and among the 3 severity groups of emphysema. The correlation between LAA% and T values was evaluated. The LAA% cut-off value in COPD patients for developing osteoporosis was determined using the receiver operating characteristic (ROC) curve. Results The T values decreased significantly in mild (T=0.081依0.74, LAA%=6.83依 1.37), moderate (-1.584依1.08, 15.77依2.81), and severe (-2.77依1.11, 29.26依6.05) emphysema. The LAA% was significantly negatively correlated with BMD T values (R=-0.806, P<0.05). Using the LAA% cutoff value of 19.7%, the area under the ROC curve for predicting osteoporosis was 0.950 (P<0.05) with sensitivity of 94.7% and specificity of 86.6%. Conclusion There is positive correlation between severity of emphysema and osteoporosis with cutoff value of >19.7%LAA%for developing osteoporosis. [ABSTRACT FROM AUTHOR]

BACKGROUND: Percutaneous vertebroplasty is one of the effective treatments for osteoporotic vertebral compression fractures. The distribution of bone cement in the vertebral body will influence the clinical efficacy. OBJECTIVE: To investigate the influence of the distribution of bone cement in percutaneous vertebroplasty on the early postoperative outcomes after osteoporotic vertebral compression fractures. METHODS: A total of 132 patients, including 52 males and 80 females, with a mean age of (76.3±8.2) years who diagnosed as osteoporotic vertebral compression fractures in First Hospital of Shanxi Medical University from January 2017 to June 2019 were enrolled. All patients were divided into underdispersion group (n=54) and diffuse distribution group (n=78) according to the pattern of cement distribution on postoperative X-rays. Visual analogue scale scores postoperatively, the height of anterior edge and midline of injured vertebrae, Cobb angle of local kyphosis and the incidence of complications after 1-year follow-up were compared between the two groups. The trial was performed in accordance with the relevant ethical requirements for research in the First Hospital of Shanxi Medical University. RESULTS AND CONCLUSION: (1) The visual analogue scale scores were lower at 2 days, 1 and 6 months after operation than those before operation in the two groups (P < 0.05). The visual analogue scale scores at 1 month after operation in the underdispersion group were higher than those in the diffuse distribution group (P < 0.05), and there was no significant difference between the two groups at 2 days and 6 months after operation (P > 0.05). (2) Cobb angle and vertebral body height improved in both groups postoperatively compared to preoperatively (P < 0.05). The difference in Cobb angle and vertebral body height was not statistically significant between the two groups (P > 0.05). (3) The rate of bone cement infiltration was not significantly different between the two groups (P > 0.05). Incidence of recurrent fractures in adjacent vertebrae was lower in the diffuse distribution group than that in the underdispersion group (P < 0.05). (4) These findings confirm that percutaneous vertebroplasty is an effective treatment for osteoporotic vertebral compression fractures. The distribution of bone cement in the vertebral body will affect the surgical results. The bone cement is diffusely distributed, which may reduce the incidence of recurrent fractures in adjacent vertebrae. [ABSTRACT FROM AUTHOR]

Objective: To compare the clinical value of low dose and conventional dose scanning in CT guided percutaneous lung biopsy. Methods: 96 patients with CT guided percutaneous lung biopsy in our hospital were selected from January 2018 to December 2019, and they were divided into low dose group and conventional dose group by using random digital table method. 48 patients in each group. The two groups were CT guided percutaneous lung biopsy under low dose scanning and conventional dose scanning respectively. The scanning range, X-ray dose, image quality, puncture success rate and complications were compared between the two groups. Results: The CT absorbed dose weighted index (CTDIW) and the product of average dose length (DLP) in the low dose group were significantly lower than those in the conventional dose group (P<0.05), and there was no significant difference in the scanning range between the two groups (P>0.05). In the low dose group, the image quality was grade 1 in 1 case, grade 2 in 1 case and grade 3 in 46 cases, in the routine dose group: Grade 1 in 0 cases, grade 2 in 1 case, grade 3 in 47 cases, there was no significant difference in image quality between the two groups (P>0.05). The success rate of low dose group was 87.50%, while that of conventional dose group was 89.58%. There was no significant difference between the two groups (P>0.05). The incidence of complications was 12.50% in the low-dose group and 10.42% in the conventional dose group. There was no significant difference between the two groups (P>0.05). Conclusion: Compared with conventional dose scanning, low dose scanning in CT guided percutaneous lung biopsy can effectively reduce the radiation dose, but it does not affect the image quality and the success rate of puncture, and the incidence of complications has not increased. [ABSTRACT FROM AUTHOR]

ACKGROUND: The single volar locking plate internal fixation is often used for type C distal radius fractures. However, some patients still fail to achieve good fracture reduction, and the grip strength of the affected limb is significantly weakened. How to restore the length of the radius and maintain the reduction and internal fixation during the operation is challenging. OBJECTIVE: To compare the clinical efficacy of external fixator-assisted reduction and locking plate internal fixation and simple locking plate internal fixation in the treatment of type C distal radius fractures. METHODS: A retrospective analysis was conducted in 93 patients with type C distal radius fractures who underwent surgical treatment from March 2017 to August 2019. There were 49 cases in the external fixator-assisted group, with an average follow-up period of (14.95±5.64) months (range, 6-30 months); there were 44 cases in the simple plate group, with an average follow-up period of (15.38±6.27) months (range, 6 to 24 months). The preoperative general information, surgical related indicators, postoperative follow-up X-ray measurements and wrist function were compared and analyzed between the two groups. RESULTS AND CONCLUSION: (1) The operation time, incision length, and number of X-ray exposures in the external fixator-assisted group were less than those in the simple plate group, and the differences were statistically significant (P < 0.05). (2) During the postoperative follow-up, the degree of radial height recovery in the external fixator-assisted group was better than that of the simple plate group, and the difference was statistically significant (P < 0.05). There was no statistical difference in the recovery of palm tilt and ulnar deviation between the two groups (P > 0.05). (3) On the second day after operation, the visual analogue scale score of the external fixator-assisted group was higher than that of the simple plate group, and the difference was statistically significant (P < 0.05). (4) At 1-year follow-up, the degree of grip strength recovery in the external fixator-assisted group was better than that in the simple plate group, and the difference was statistically significant (P < 0.05). (5) The results show that both methods can effectively reduce and fix type C distal radius fractures, and restore wrist function. The external fixator-assisted group has advantages such as shorter operation time, less trauma, less X-ray radiation, and better grip strength in comparison to the simple plate group. [ABSTRACT FROM AUTHOR]

BACKGROUND: The details of clinical symptoms of osteoporotic vertebral fracture with intravertebral clefts are poorly understood at present. OBJECTIVE: To investigate the relationship between clinical symptoms and imaging features of osteoporotic vertebral fracture with intravertebral clefts. METHODS: Clinical data of 168 patients with single-level osteoporotic vertebral fracture with intravertebral clefts were retrospectively analyzed. The clinical symptoms were evaluated by Visual Analogue Scale score and Oswestry Disability Index. The incidence of delayed neurologic deficit was recorded. X-ray was used to measure the local kyphosis angle and vertebral instability, and CT was used to diagnose the posterior wall fracture of the vertebral body. The relationship between clinical symptoms and imaging features of osteoporotic vertebral fracture with intravertebral clefts was analyzed. RESULTS AND CONCLUSION: (1) The Visual Analogue Scale score and Oswestry Disability Index were 7.7±1.6 and (62.9±19.2)%, respectively. Delayed neurologic deficit occurred in 37 patients (22.0%). Local kyphosis angle and vertebral instability was (16.8±7.7)° and (7.9±4.4)°, respectively. The incidence of posterior wall fracture was 89.8%. (2) The Visual Analogue Scale and Oswestry Disability Index were significantly correlated with vertebral instability (r=0.33, P < 0.001; r=0.53, P < 0.001), but had weak correlation with local kyphosis angle (r=-0.16, P=0.03; r=-0.16, P=0.03). (3) The incidence of vertebral instability in patients with delayed neurologic deficit was significantly higher than that in patients without delayed neurologic deficit (P < 0.001), but there was no difference in local kyphosis angle between two groups (P=0.18). All patients with delayed neurologic deficit had posterior wall fracture, but only 2/3 patients with posterior wall fracture had delayed neurologic deficit. (4) In summary, vertebral instability is one of the factors leading to clinical symptoms of osteoporotic vertebral fracture patients with intravertebral clefts. The vertebral instability may be the main cause of delayed neurologic deficit. In order to treat back pain and delayed neurologic deficit effectively, it is important to control vertebral instability of osteoporotic vertebral fracture patients with intravertebral clefts. [ABSTRACT FROM AUTHOR]

Objective: To explore the correlation between the prognosis of radiofrequency ablation (RFCA) and the origins in patients with premature ventricular contractions (PVCs). Methods: Clinical data of PVCs patients admitted to the department of cardiovascular medicine of Changhai hospital, the first affiliated hospital of the second military medical university, and treated with RFCA from December 2016 to December 2017 were retrospectively analyzed, and were divided into right ventricle group (n=58) and left ventricle group (n=24) according to the origins. The operation time of RFCA, X-ray exposure time, operation success rate and other indicators of the two groups were recorded. The patients were followed up for 6 months after the operation. The improvement of cardiac function indicators in the two groups after the operation was compared, and the total number of 24 h PVCs and the recurrence were recorded. Results: Compared with the left ventricle group, the operation time and X-ray exposure time in the right ventricle group were significantly prolonged, and the success rate of surgery was significantly decreased (P<0.05). At 6 months after surgery, the number of 24 h PVCs in both groups was significantly lower than that before surgery, and the decline was more significant in the right ventricle group (P<0.05). Three months after surgery, LVESD and LVEDD were significantly decreased and LVEF was significantly increased in the right ventricle group (P<0.05). At 6 months after surgery, all cardiac function indicators in the two groups were significantly improved compared with those before surgery, and the right ventricle group was further improved compared with that at 3 months after surgery, and was significantly better than that in the left ventricle group (P<0.05). Conclusions: The prognosis of PVCs has a certain correlation with the site of origin. The success rate of right ventricular origin PVCs is higher than that of left ventricular origin, which is more conducive to improving cardiac structural remodeling and function. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of 64-slice spiral CT on Evans classification of intertrochanteric fractures, and to provide reference for clinical use. Methods: From March 2015 to March 2017, 128 patients with unilateral unilateral intertrochanteric fractures were classified by Evans according to preoperative X-ray, preoperative 64-slice spiral CT plain scan and three-dimensional reconstruction, and were classified into X-ray and CT types. According to the perioperative X-ray, CT and intraoperative findings of the fracture, Evans classification(inverse intertrochanteric fracture defined as type V) as the final classification. The typing results were recorded, and the accuracy and misdiagnosis rate were calculated and compared. Results: 5 patients were excluded and 90.09%(123/128)completed the study. Typing results: 3 cases(2 cases of final type III, 1 case of type IV) could not be typed; 1 case of correct type I was changed to type II 1 case; 18 cases of correct type II were changed to type I 2 cases, changed to type III 3 cases, changed to type IV 2 cases; 45 cases of correct type III, changed to type II 7 cases, changed to type IV 1 case; 19 cases of correct type IV, changed to type II 3 cases. 15 cases were changed to type III. Among the CT typing, 3 were correct in type I, 29 in type II, 64 in type III, 1 in type IV, 22 in type IV, and 3 in type V. The total accuracy and misdiagnosis rate of CT typing were better than that of X-ray typing(99.19% vs 67.48%,0.81% vs 30.08%, P<0.05). For type I, type II, type III and type IV fractures, the accuracy of CT classification was higher than that of X-ray classification(P<0.05), and the misdiagnosis rate was lower than that of X-ray classification(P<0.05); for type V fractures, the accuracy and misdiagnosis rate of the two types were equal. Conclusion: 64-slice spiral CT plain scan and three-dimensional reconstruction are reliable auxiliary examinations for Evans classification of intertrochanteric fractures, and can be considered for popularization and application. [ABSTRACT FROM AUTHOR]

The effect of corn straw ash with different content(0%, 5%, 10% and 15%) on compressive strength and water purification characteristics of concrete was studied. The microstructure of corn stalk ash was determined by X ray diffraction(XRD). And the chemical composition was determined by X ray fluorescence(XRF). Concrete compressive strength was measured using standard methods. The water purification performance mainly tested several indicators such as water pH value, total dissolved solids(TDS), total nitrogen content and chemical oxygen demand(COD). The results showed that: for corn stalk ash with more than 70% of pozzolanic activity content, the compressive strength of specimens mixed with concrete was significantly higher than that of unmixed specimens. And the optimal dosage of corn straw was 10%. The concrete mixed with straw ash in the water purification test to maintain the pH of the test water at 7 to 10, was conducive to the purification of water purification microorganisms. The concrete mixed with straw ash had a good removal effect on TDS and total nitrogen content in sewage. The COD removal efficiency in the sewage was poor in the early stage of the test. However, when the biofilm was formed on the surface of the sample, the water purification effect was significantly enhanced. When the design porosity was 20% and the corn straw ash content was 10%, the biomass concrete has greater compressive strength and better water purification performance. [ABSTRACT FROM AUTHOR]

BACKGROUND: Navigation systems all can improve the accuracy rate in cervical pedicle screw insertion, but cannot achieve desired outcomes because of some shortcomings, such as poor imaging quality, complicated operation, poor real-time performance, and invasive navigation. OBJECTIVE: To study the accuracy of X-ray fluoroscopy and CT three-dimensional image navigation in cervical pedicle screw insertion. METHODS: Totally 90 patients undergoing cervical pedicle screw insertion from the First Affiliated Hospital of Nanyang Medical College were enrolled, and randomly divided into control and experimental groups (n=45 per group). 132 cervical pedicle screws were inserted into the patients in the control group manually under X-ray fluoroscopy, and 128 ones were inserted into the patients in the experimental group assisted with CT three-dimensional image navigation. The operation time and intraoperative blood loss in the two groups were recorded. Postoperative CT three-dimensional reconstruction was performed to compare the placement accuracy between two groups. RESULTS AND CONCLUSION: The excellent and good rate of placement in the experimental group (95.3%) was significantly higher than that in the control group (88.6%, P < 0.05). (2) The operation time and intraoperative blood loss in the experimental group were significantly higher than those in the control group, and the navigation matching time and radiant quantity in the experimental group were significantly less than those in the control group (P < 0.05). (3) The Japanese Orthopedic Association scores showed no significant difference between two groups before surgery (P > 0.05), and were significantly improved in the experimental group compared with the control group at 3 and 6 months postoperatively (P < 0.05). The incidence of complications in the experimental group was significantly lower than that in the control group (7% versus 16%, P < 0.05). (5) These results suggest that compared with X-ray fluoroscopy, CT three-dimensional image navigation can improve the accuracy of cervical pedicle screw insertion, showing higher safety and precision. However, it needs complicated operation skills, and long operation time results in massive intraoperative blood loss; thereafter, choosing which placement method depends on the patient condition. [ABSTRACT FROM AUTHOR]

The purpose of the experiment was to explore the feature on grayscale of CT images during frozen soil thawing. Siltyclay sample was taken into isothermal air (20 °C) to melt by natural convection after being frozen at -27 °C, and the CT images were obtained by X-ray scan, at the same time, its temperature-time history was recorded. The curve of grayscale-time was acquired by counted CT images at each moment, and compared with its temperature-time history. The results show that the average grayscale increases obviously with temperature rising and thawing in frozen soil. However, after sample thaws completely, the average grayscale is not practically changing even temperature still rising. A break point is obviously observed in the graph of grayscale-time at the moment of phase-ransition finished, which is considered as a symbol of frozen soil melting complete. [ABSTRACT FROM AUTHOR]

In tooth implantation surgery, it is important to acquire tooth-root orientation and the distribution of mandibular canal. However, these structures can't be shown clearly in panoramic radiography generated by X-ray machine. This paper proposed a metiiod to generate virtual dental panoramic radiographs (VDPR) from 3D CT images and enhanced tooth-root and mandibular canal in VDPR. The transfer function was redesigned to enhance tooth-root, and the mandibular canal was enhanced by incorporating its spatial information. In the end, some experiments show that tooth-root and mandibular canal are enhanced and clearly shown in VDPR. So the proposed method is effective and helpful in tooth implantation surgery. [ABSTRACT FROM AUTHOR]