After the production of the gradient coil of the magnetic resonance imaging system, electromagnetic field testing is required to verify whether the assembly accuracy meets the electromagnetic field requirements. Since the passive magnetic field B _z satisfies the Laplace ^,s equation and is a harmonic function, and according to the extreme value principle of harmonic function, the maximum or minimum values of B _z can only appear on the boundaries, so the observation points of the magnetic field are generally selected on the surface of the spherical imaging area. For superconducting magnets used for human body magnetic resonance imaging, a spherical area with a center diameter of 40~50 cm is generally selected as the shimming target area. Only the field value of the target area needs to be measured, and the spherical harmonic coefficients obtained after data processing are used to determine the magnetic field performance of the gradient coil. There are many testing principles and methods for electromagnetic fields, so there is no unified way and method in the field of commercial applications. This article is based on the Gauss-Legendre numerical integration, measures and analyzes the magnetic field performance of gradient coils by building a data acquisition system, and this article applies numerical analysis methods to calculate the spherical harmonic coefficients of the magnetic field using discrete test data, providing a feasible method for the production and testing of gradient coils.
Magnetic Resonance Imaging/methods* ; Magnetic Fields ; Electromagnetic Fields ; Equipment Design

The casting and curing of gradient coils in the production process is a relatively complex process. The chemical process similar to the black box model requires confirmation of the impact of each step of input on the output results, while the curing temperature and molding method affect the roundness and deformation of the gradient coils. The analysis of the curing temperature and demolding method of gradient coils has important practical significance for the formation and micro deformation of gradient coils. This article uses ANSYS finite element simulation software to analyze the thermal structural coupling and the specific performance of actual products. It has been found that the product quality is more stable under the heat conduction mode, and the roundness of the mold is better when placed vertically and waiting for temperature cooling before being demolding than when placed horizontally.

OBJECTIVETo screen methylations of CpG islands in prostate cancer using restriction landmark genomic scanning (RLGS).

METHODSThe DNA was extracted from homogeneous cells captured by laser capture microdissection in 20 prostate cancer and 18 benign prostatic hyperplasia (BPH) tissues for scanning the CpG islands using RLGS. The methylation status of each CpG island was compared between the cancer and BPH samples to screen the genes involved in prostate cancer development. The screened genes were uploaded to DAVID database for GO analysis, and the genes with the most significant methylation were analyzed by pyrosequencing.

RESULTS AND CONCLUSIONAmong all the tested CpG islands, 10245 (37.2%) in prostate cancer and 8658 (30.3%) in BPH samples were found to be abnormally methylated, and >60% of the methylated CpG islands were in the promoter region. Compared with BPH samples, the prostate cancer samples showed differential methyation in 735 CpG islands, including 458 hepermethyated and 256 hypomethelated ones. Seven genes (DPYS, P16, APC, GSTP1, TMEM122, RARB, and ARHGAP20) in prostate cancer were identified to have distinct methylations. Bioinformatics analysis suggested that these genes were associated with several biomolecular and biological processes, and among them DPYS gene was involved in 13 GO anotated biologic functions, development of 50 diseases and 47 protein interactions. Pyrosequencing of 7 sites of the CPG island in DPYS gene showed a methylation frequency of 32.7%, suggesting the importance of DPYS gene in the carcinogenesis and progression of prostate cancer.

CpG Islands ; DNA Methylation ; DNA, Neoplasm ; genetics ; Genomics ; Humans ; Male ; Polymerase Chain Reaction ; Prostatic Hyperplasia ; genetics ; Prostatic Neoplasms ; diagnosis ; genetics

OBJECTIVETo compare the safety, feasibility and efficacy of transperitoneal and retroperitoneal laparoscopic partial nephrectomy (LPN) in the treatment of renal tumors with R. E. N. A. L score more than 7.

METHODSThe clinical data were collected from 62 patients undergoing transperitoneal LPN (32 cases) and retroperitoneal LPN (30 cases) for a complex renal mass (R.E.N.A.L. score≥7) between January 2012 and March 2014. The surgical and early postoperative outcomes and complications were analyzed to evaluate the efficacy of the treatments. The mean operative time, estimated blood loss, warm ischemia time, surgical complications, blood transfusion rate, tolerating regular diet time, postoperative hospital stay and surgical margin were compared between the two groups.

RESULTSThe operations were completed successfully in all cases except for 1 case in transperitoneal group and 3 in retroperitoneal group that required conversion to open surgery. No significant differences were found in age, body mass index, ASA score, Charlson comorbidity index, tumor size or R.E.N.A.L. nephrometry score (P>0.05), nor in estimated blood loss, warm ischemia time, intraoperative complication, blood transfusion rate or surgical margin between the two groups (P>0.05, respectively). The transperitoneal LPN group had a shorter mean operative time than retroperitoneal LPN group (210.4∓59.2 vs 252∓58.3 min, P<0.05) but showed longer tolerating regular diet time (47∓10 h vs 23∓6 h, P<0.05) and postoperative hospital stay time (8.4∓1.9 days vs 6.5∓1.6 days, P<0.05).

CONCLUSIONBoth transperitoneal LPN and retroperitoneal LPN are safe, feasible and effective for surgical management of complex localized tumors, but the transperitoneal procedure offers larger operative space with better exposure; the retroperitoneal procedure better promotes postoperative recovery of the patients.

Humans ; Kidney Neoplasms ; diagnosis ; surgery ; Laparoscopy ; Length of Stay ; Nephrectomy ; Operative Time ; Retroperitoneal Space ; Retrospective Studies ; Treatment Outcome

OBJECTIVETo explore the clinical value of preserving the integrity of the bladder neck in plasmakinetic vaporization of the prostate (PKVP) in protecting the erectile function and improving the quality of life of patients with benign prostatic hyperplasia (BPH) below 60 years of age.

METHODSThirty-two patients with BPH, with a mean age of 55.4 years (range 50-60 years), were enrolled the study to undergo PKVP with Gyrus bipolar systems, in which the transverse fiber muscle area of the bladder neck were carefully preserved. The erectile function and the quality of life of the patients were evaluated with the International Index of Erectile Function (IIEF)-5 and Quality of Life (QoL) before and after the operation. Retrograde ejaculation was also observed after the operation.

RESULTSIn the 6-month follow-up, only 1 (3.13%) patient was found to have erectile dysfunction. Five patients (15.6%) reported retrograde ejaculation 3 months after the surgery, and only 3 patients (9.4%) had retrograde ejaculation at 6 months.

CONCLUSIONSPreserving the bladder neck in PKVP may protect the erectile function with BPH below 60 years of age.

Erectile Dysfunction ; prevention & control ; Humans ; Laser Therapy ; Male ; Middle Aged ; Organ Sparing Treatments ; Penile Erection ; Prostatic Hyperplasia ; surgery ; Quality of Life ; Urinary Bladder ; Volatilization

Objective To explore the clinical value of preserving the integrity of the bladder neck in plasmakinetic vaporization of the prostate (PKVP) in protecting the erectile function and improving the quality of life of patients with benign prostatic hyperplasia (BPH) below 60 years of age. Methods Thirty-two patients with BPH, with a mean age of 55.4 years (range 50-60 years), were enrolled the study to undergo PKVP with Gyrus bipolar systems, in which the transverse fiber muscle area of the bladder neck were carefully preserved. The erectile function and the quality of life of the patients were evaluated with the International Index of Erectile Function (IIEF)-5 and Quality of Life (QoL) before and after the operation. Retrograde ejaculation was also observed after the operation. Results In the 6-month follow-up, only 1 (3.13%) patient was found to have erectile dysfunction. Five patients (15.6%) reported retrograde ejaculation 3 months after the surgery, and only 3 patients (9.4%) had retrograde ejaculation at 6 months. Conclusion Preserving the bladder neck in PKVP may protect the erectile function with BPH below 60 years of age.

Objective To compare the safety, feasibility and efficacy of transperitoneal and retroperitoneal laparoscopic partial nephrectomy (LPN) in the treatment of renal tumors with R. E. N. A. L score more than 7. Methods The clinical data were collected from 62 patients undergoing transperitoneal LPN (32 cases) and retroperitoneal LPN (30 cases) for a complex renal mass (R.E.N.A.L. score≥7) between January 2012 and March 2014. The surgical and early postoperative outcomes and complications were analyzed to evaluate the efficacy of the treatments. The mean operative time, estimated blood loss, warm ischemia time, surgical complications, blood transfusion rate, tolerating regular diet time, postoperative hospital stay and surgical margin were compared between the two groups. Results The operations were completed successfully in all cases except for 1 case in transperitoneal group and 3 in retroperitoneal group that required conversion to open surgery. No significant differences were found in age, body mass index, ASA score, Charlson comorbidity index, tumor size or R.E.N.A.L. nephrometry score (P>0.05), nor in estimated blood loss, warm ischemia time, intraoperative complication, blood transfusion rate or surgical margin between the two groups (P>0.05, respectively). The transperitoneal LPN group had a shorter mean operative time than retroperitoneal LPN group (210.4±59.2 vs 252±58.3 min, P<0.05) but showed longer tolerating regular diet time (47 ± 10 h vs 23 ± 6 h, P<0.05) and postoperative hospital stay time (8.4 ± 1.9 days vs 6.5 ± 1.6 days, P<0.05). Conclusion Both transperitoneal LPN and retroperitoneal LPN are safe, feasible and effective for surgical management of complex localized tumors, but the transperitoneal procedure offers larger operative space with better exposure; the retroperitoneal procedure better promotes postoperative recovery of the patients.

Objective To explore the clinical value of preserving the integrity of the bladder neck in plasmakinetic vaporization of the prostate (PKVP) in protecting the erectile function and improving the quality of life of patients with benign prostatic hyperplasia (BPH) below 60 years of age. Methods Thirty-two patients with BPH, with a mean age of 55.4 years (range 50-60 years), were enrolled the study to undergo PKVP with Gyrus bipolar systems, in which the transverse fiber muscle area of the bladder neck were carefully preserved. The erectile function and the quality of life of the patients were evaluated with the International Index of Erectile Function (IIEF)-5 and Quality of Life (QoL) before and after the operation. Retrograde ejaculation was also observed after the operation. Results In the 6-month follow-up, only 1 (3.13%) patient was found to have erectile dysfunction. Five patients (15.6%) reported retrograde ejaculation 3 months after the surgery, and only 3 patients (9.4%) had retrograde ejaculation at 6 months. Conclusion Preserving the bladder neck in PKVP may protect the erectile function with BPH below 60 years of age.

Objective To compare the safety, feasibility and efficacy of transperitoneal and retroperitoneal laparoscopic partial nephrectomy (LPN) in the treatment of renal tumors with R. E. N. A. L score more than 7. Methods The clinical data were collected from 62 patients undergoing transperitoneal LPN (32 cases) and retroperitoneal LPN (30 cases) for a complex renal mass (R.E.N.A.L. score≥7) between January 2012 and March 2014. The surgical and early postoperative outcomes and complications were analyzed to evaluate the efficacy of the treatments. The mean operative time, estimated blood loss, warm ischemia time, surgical complications, blood transfusion rate, tolerating regular diet time, postoperative hospital stay and surgical margin were compared between the two groups. Results The operations were completed successfully in all cases except for 1 case in transperitoneal group and 3 in retroperitoneal group that required conversion to open surgery. No significant differences were found in age, body mass index, ASA score, Charlson comorbidity index, tumor size or R.E.N.A.L. nephrometry score (P>0.05), nor in estimated blood loss, warm ischemia time, intraoperative complication, blood transfusion rate or surgical margin between the two groups (P>0.05, respectively). The transperitoneal LPN group had a shorter mean operative time than retroperitoneal LPN group (210.4±59.2 vs 252±58.3 min, P<0.05) but showed longer tolerating regular diet time (47 ± 10 h vs 23 ± 6 h, P<0.05) and postoperative hospital stay time (8.4 ± 1.9 days vs 6.5 ± 1.6 days, P<0.05). Conclusion Both transperitoneal LPN and retroperitoneal LPN are safe, feasible and effective for surgical management of complex localized tumors, but the transperitoneal procedure offers larger operative space with better exposure; the retroperitoneal procedure better promotes postoperative recovery of the patients.

OBJECTIVETo evaluate the effects of different CO(2) pneumoperitoneum conditions on renal function in rats and provide experimental evidence for improving renal graft function after transplantation.

METHODSSD rats were randomized into 10 groups (n=12) and subject to CO(2) pneumoperitoneum at different pressures (0.67, 1.33 and 2.0 kPa) for 60 or 120 min. Serum urea nitrogen (BUN), creatinine (Cr) and N-acetyl-β-D-glocosaminidase (NAG) levels were detected after pneumoperitoneum.

RESULTSAs the pressure and time of pneumoperitoneum increased, the renal function deteriorated gradually, showing significant differences between the groups (P<0.05).

CONCLUSIONIncreased pressure and prolonged duration of CO(2) pneumoperitoneum causes impairment of the renal function, suggesting the necessity of reducing the operative time and lowering the pressure of pneumoperitoneum when harvesting renal graft in living donors.

Animals ; Carbon Dioxide ; Female ; Kidney ; physiology ; Kidney Transplantation ; Laparoscopy ; methods ; Male ; Nephrectomy ; methods ; Pneumoperitoneum, Artificial ; adverse effects ; methods ; Rats ; Rats, Sprague-Dawley ; Retroperitoneal Space ; surgery ; Time Factors ; Tissue and Organ Harvesting ; methods