Optimization design and analysis of mobile pump truck frame using response surface methodology.

In order to realize the lightweight design of mobile pump truck, this paper takes the frame of a certain type of mobile pump truck as the research object. The response surface method is used to carry out lightweight design of the longitudinal beam structure of the frame, and the finite element method is used to establish the finite element model to compare and analyze the optimized and original designs. The results show that the height, width and thickness of the optimized longitudinal beam section are reduced by 10mm, 11mm, and 0.8mm respectively, and the weight of the whole frame is reduced by 35.8kg. Before and after optimization, the displacement and stress changes of the frame are small in four motion situations, which meet the lightweight requirements of optimization design.

Prenatal diagnosis of triphalangeal thumb-polysyndactyly syndrome by ultrasonography combined with genetic testing: A case report.

BACKGROUND: Triphalangeal thumb-polysyndactyly syndrome (TPT-PS) is a rare type of congenital limb deformity, and most studies focus on the genetics. Case reports of the sonographic characteristics of TPT-PS during pregnancy are rare. CASE SUMMARY: A 30-year-old woman (G3P1) who had pregnancies with TPT-PS fetuses is presented. The possibility of TPT-PS was shown by ultrasound performed at the 19th wk of pregnancy, featuring hands with six metacarpals, an extra digit at the 5th finger side, and an abnormally widened thumb. Whole-exome sequencing was subsequently conducted. The results showed that exons 1-17 of the LMBR1 gene had a heterozygous duplication, with a length of approximately 253 kb. CONCLUSION: We suggest prenatal ultrasound examination combined with genetic testing to diagnose TPT-PS accurately and to help clinicians and patients make decisions.

The value of repeated CT in monitoring the disease progression in moderate COVID-19 pneumonia: A single-center, retrospective study.

ABSTRACT: The role of thoracic CT (computerized tomography) in monitoring disease course of COVID-19 is controversial. The purpose of this study is to investigate the risk factors and predictive value of deterioration on repeatedly performed CT scan during hospitalization.All COVID-19 patients treated in our isolation ward, from January 22, 2020 to February 7, 2020, were reviewed. Patients included were categorized into RD (Radiological Deterioration) group or NRD (No Radiological Deterioration) group according to the manifestation on the CT routinely performed during the hospitalization. All clinical data and CT images were analyzed.Forty three patients were included in our study. All are moderate cases with at least 4 CT scans each. Eighteen (42.9%) patients had radiological deteriorations which were all identified in CT2 (the first CT after admission). Patients in RD group had lower leukocyte count (P = .003), lymphocyte count (P = .030), and higher prevalence (P = .012) of elevated C-reactive protein (CRP) at admission. NRD patients had a lower prevalence of reticulations (P = .034) on baseline CT (CT1, performed within 2 days before admission) and a longer duration between symptom onset and the time of CT2 (P < .01). There was no significant difference in hospital stay or fibrotic change on CT4 (follow-up CT scan performed 4 weeks after discharge) between 2 groups. Shorter duration between symptom onset and CT2 time (odds ratio [OR], 0.436; 95% confidence interval: 0.233-0.816; P < .01) and lower leukocyte count in baseline evaluation (OR, 0.316; 95% CI: 0.116-0.859; P < .05) were associated with increased odds of radiological deterioration on CT image during hospitalization.For moderate COVID-19 patients, the value of routinely performed CT during the treatment is limited. We recommend avoiding using CT as a routine monitor in moderate COVID-19 patients.

Morphometric measurement of lower lumbar intervertebral foramina based on digital three-dimensional simulation.

AIM: This study aimed to investigate the morphology of the lower lumbar intervertebral foramina through use of a digital three-dimensional (3D) simulation model to guide the endoscope through the intervertebral foramina. MATERIAL AND METHODS: Individuals without disease affecting the lumbar vertebrae underwent computed tomography (CT) scanning in the supine position. The CT images obtained were imported to medical software to reconstruct a 3D model of the lumbar vertebrae. The stereoscopic longitudinal and transverse diameters of the lumbar intervertebral foramina were measured directly on the established simulation model. Comparisons in terms of sex and age were performed using t-test or analysis of variance. RESULTS: In total, 100 individuals were included in the study. Average longitudinal and transverse diameters of the lower lumbar intervertebral foramen decreased moving inferiorly. The longitudinal and transverse diameters of the lower lumbar intervertebral foramina were similar between sexes and between age groups. However, longitudinal diameter decreased with age (P 0.05). CONCLUSION: The reconstructed lumbar vertebrae simulation model presented in this study has high fidelity to the structure of the human lumbar spine. This approach provides individualized, accurate, standardized, and detailed guidance for endoscopic surgery through the lumbar intervertebral foramen.

Grass carp (Ctenopharyngodon idellus) invariant chain of the MHC class II chaperone protein associates with the class I molecule.

The invariant chain (Ii) is an important immune molecule, as it assists major histocompatibility complex (MHC) class II molecules to present antigenic peptides. The relationship between the Ii and MHC molecules in teleosts remains poorly understood. This study focused on the molecular structure of grass carp Ii (gIi), its organ distribution, correlations with gene transcription, and the association with MHC. gIi cDNA was cloned using designed degenerate primers and the rapid amplification of cDNA ends method (RACE). The gIi sequence was 92%-96% similar to that of other teleosts, but only 52%-67% similar to that of mammals, respectively. The gIi gene was distributed in all 12 organs examined by PCR. The gIi gene transcription levels were markedly higher in organs enriched with immune cells than in other organs (P < 0.01). Moreover, positive correlations were detected between transcription levels of the gIi and gMhcI or II genes in different organs (r = 8.415-8.523, P = 0.001). The gIi co-localized on endomembrane systems with either class I or II molecules in co-transfected cells observed by a laser confocal. Further testing confirmed that the gIi bound gMHCI and II molecules. Taken together, these results indicate that the gIi is associated with MHC class I and II molecules, suggesting homology of both MHC molecules.

[Preliminary clinical study on the posterior lumbar minimally invasive surgery assisted by 3D-Viewer system under a direct vision].

OBJECTIVE: To study the methods and preliminary clinical efficacy of posterior lumbar minimally invasive surgery assisted by 3D-Viewer system under a direct vision and provide rationales for further clinical applications. METHODS: From September 2008 to September 2009, a total of 84 lumbar degenerative disease patients were enrolled and randomly divided into 2 groups (n = 42 each). One group was treated operatively by 3D-Viewer system under a direct vision while another treated with conventional operations. The lumbar paraspinal muscle approach was employed. Surgery was assisted by 3D-Viewer system under a direct vision. The operative duration, intra-operative blood loss volume, CK (creatine kinase) levels at Days 1 & 7 post-operation, atrophic rates of cross-sectional areas of bilateral multifidus muscles on MRI (magnetic resonance imaging) at 12 months post-operation were recorded. At Month 12 post-operation, the therapeutic efficacy was evaluated by Oswestry disability index (ODI) and the post-operative clinical effects assessed. RESULTS: The operative duration, intra-operative blood loss volume and CK level at Days 1 & 7 post-operation were statistically different (P < 0.05); there was significant difference in the atrophic rates of cross-sectional areas of bilateral multifidus muscles on MRI and the improvement rates of ODI (P < 0.001); the therapeutic efficacy of the invasive group was significantly better than that of the group treated with traditional operations (P < 0.05). CONCLUSION: The 3D-Viewer technique reduces the risk of damage. As an ideal minimally invasive procedure, it may achieve satisfactory outcomes for spinal diseases.

[The correlation between the level of serum VEGF and bFGF with metastasis and prognosis of osteosarcoma].

AIM: To investigate the correlation between the level of serum VEGF and bFGF with metastasis and re- currence of osteosarcoma. METHODS: 52 patients with osteosarcoma and 60 healthy people as control group were selected. The serum contents of VEGF and bFGF were determined with ELISA before and after operation. RESULTS: The serum contents of VEGF and bFGF before operation were significantly higher than that in control group ( P < 0.01). The serum contents of VEGF and bFGF after operation descreased significantly but were significantly higher than that in control group(P<0. 01). The serum contents of VEGF and bFGF before operation were positively related to the size of primarily tumor, Enneking type and tumor differentiation(P<0.05). The serum contents of VEGF and bFGF before and after operation were different significantly between recurrence and metastasis positive group with recurrence and metastasis negative group ( P < 0. 01). The Cox proportional hazards model showed that the serum contents of VEGF and bFGF before and after operation were an independent factor of the recurrence and metastasis for osteosar- coma patients after operative ( P <0. 01). CONCLUSION: The serum contents of VEGF and bFGF before and after operation can offer valuable assessments in evaluation of progression and metastasis prognosis.

[Metrx quadrant system in the surgery of lumbar spondylolisthesis: preliminary clinical application].

OBJECTIVE: To evaluate the clinical efficacy and minimal invasiveness of quadrant posterior distraction system in the posterior lumbar spondylolisthesis (LS) surgery. METHODS: Sixty-one LS patients were randomly divided into two groups: quadrant posterior minimally invasive surgery system as invasive group (n = 30) and traditional open surgery as open group (n = 31). The clinical outcome of pain relief was assessed by the scoring systems of visual analogue scale (VAS) and Oswestry disability index (ODI) for low back pain. Radiographic assessment: preoperative and 1-day, 3-month and last follow-up (12 months) radiographs were analyzed including the index of relative posterior disc height. RESULTS: The scores of VAS and ODI of invasive group were less than open group at Months 3 and 12 post-operation (P < 0.01). Relative posterior disc height of intra-operation and Month 3 was not significantly different (P > 0.05). And there was only statistical significance difference within 12 months (P < 0.05). At Month 12 post-operation, the fluctuating rate was slight. CONCLUSION: The minimally invasive operation with Quadrant is less traumatic to the patients than traditional open operation in the protection of spinal stability, postoperative rehabilitation and radiographs. This new minimally invasive spine technique should be popularized.

[Experimental study of reservation flaval ligament on prevention of peridural adhesion after operation on lumbar disc].

OBJECTIVE: Through an experiment in rabbits, to evaluate the role of reservation flaval ligament using different methods to prevent the epidural adhesion by observing the morphological changes and provide experiment evidences for clinic. METHODS: 45 adult rabbits were divided into three groups: Group A (treated with no reservation of flaval ligament), Group B (treated with reserving half flaval ligament), and Group C (treated with reserving the complete flaval ligament). Every group has 15 rabbits. At the 2nd, 4th and 8th weeks, the samples were obtained for gross observation, histological examinations, and the images were analysed by computer. The data were processed using SPSS11.5. RESULT: Gross Observation and Histological Examinations, at the 2nd, 4th and 8th postoperative week, there was significant difference between the group A, B and C (gross observation: F2w=4.660, F4w=8.591, F8w=31.858, P<0.05; histological examinations: F2w=5.190, F4w=9.561, F8w=34.658, P<0.05). Images analysis: the difference was very significant in the groups at 2nd, 4th and 8th weeks (F2w=30.783, F4w=47.350, F8w=25.544, P<0.01). With time passing, the ratio became larger and larger in the same group. CONCLUSIONS: Reserving the complete flaval ligament can significantly prevent the peridural adhesion from the back as a barrier, and can reduce the adhesion formed.

[Research process on dynamic stabilization system of low back pain].

Dynamic stabilization system plays an important role in the treatment of the degenerative lumbar spine. Fusion of short movement segments has little influences on the motion of lumbar spine. Meanwhile, preservation of movements of segment can prevent the degeneration of adjacent segment and maintain the possibility of disc replacement even under the condition that facet joints need to be excised. While maintaining the normal lumbar motion, dynamic stabilization system can not only decrease the load of intervertebral disc of corresponding movement segments and provide a good environment for the recovery of intervertebral disc and soft tissues, but also delay the degeneration of small facet and reconstruct the biomechanical function of spine.

[Bony anatomical characteristics of posterolateral region of lumbar vertebrae and clinical significance thereof].

OBJECTIVE: To offer anatomical supports to the approach of lateral par interarticularis for far lateral lumbar discectomy. METHODS: In 30 lumber spine specimens taken from adult cadavers the relevant osseous distances of posterolateral region of lumbar vertebrae and its changing regularity with the sequences of lumbar spine were measured: (1) width of isthmus; (2) distance from midline to lateral border of vertebral body; (3) distance from lateral margin of isthmus to lateral border of vertebral body; (4) distance from inferior border of transverse process to superior rim of superior facet; (5) distance from accessory process to superior rim of superior facet; and (6) distance from central plane of lumbar disc to superior rim of superior facet. RESULTS: From L1-L2 towards L5-S1, the operative window representing the operating area of the approach of lateral par interarticularis for far lateral lumbar discectomy became progressively smaller in its longitudinal, transverse direction and outer exit. The distance from lateral margin of isthmus to lateral border of vertebral body representing the transverse diameter of the operative window was reduced to 0.32 cm (P < 0.05). While the distance from inferior border of transverse process to superior rim of superior facet and distance from accessory process to superior rim of superior facet representing the longitudinal diameter of operative window were reduced to 0.17 cm and 0.46 cm respectively (both P < 0.05). The distance from central plane of lumbar disc to superior rim of superior facet increased gradually from -0.20 cm in L1-2 to 0.86 cm in L5-S1 (P < 0.05). The articular process extended upward and covered more lumbar disc plane. CONCLUSION: At the level L1-L2 to L4-L5, the lateral par interarticularis approach is an easy, convenient, and anatomically favorable way to reach the far lateral lumbar disc herniation, but the progressive diminution of operative window increases the bony excision in lateral par interarticularis, root of transverse process, inferior portion of pedicle and superior portion of zygapophysial joint. At the level of 15-S1, the operative window becomes very tight. The excess of bone removal and expected instability of lumbar spine make the lateral par interarticularis approach tough to be done.

[Prevention of dura adherence in spinal canal after microendoscopic discectomy by different methods: a clinical study of 165 cases].

OBJECTIVE: To evaluate the effects of different methods in prevention of post-operational scar formation and dura adherence in the spinal canal after microendoscopic discectomy (MED). METHODS: 165 patients undergoing MED were randomly divided into 3 equal groups: Group A, with the yellow ligament dissected and with the space between vertebral laminae sprinkled with sodium hyaluronate before the closing of the incision; Group B, with the yellow ligament reserved; and Group C, with the yellow ligament reserved and with the space between vertebral laminae sprinkled with sodium hyaluronate before the closing of the incision. All the patients were followed up 2, 4, and 8 weeks, and 1 and 2 years after the operation. Japanese Orthopedic Association (JOA) scoring system was used to evaluate the outcomes. RESULTS: The JOA scores 2 weeks after MED were not significantly different among the 3 groups; and from then on the JOA scores of Groups B and C were all higher than those of group A (A and B: t(4w) = 0.602, t(8w) = 0.701, t(1y) = 0.623, t(2y) = 0.654; A and C: t(4w) = 0.833, t(8w) = 0.759, t(1y) = 0.714, t(2y) = 0.771, all P < 0.05), however, there were not significantly differences at all time points between Groups B and C (B and C: t(2w) = 0.041, t(4w) = 0.135, t(8w) = 0.980, t(1y) = 0.530, t(2y) = 0.103, all P > 0.05). CT showed that a great amount of scar was seen, surrounding the dura mater sac and nerve roots in Group A, and there was a great amount of scar outside the yellow ligament and no remarkable compression of dura mater sac and nerve roots in Groups B and C. CONCLUSION: Reservation of yellow ligament effectively prevents scar adhesion inside the vertebral canal after MED. Sprinkling of sodium hyaluronate is also effective, however, its effect only lasts a short time.