The gradient field, one of the core magnetic fields in magnetic resonance imaging (MRI) systems, is generated by gradient coils and plays a critical role in spatial encoding and the generation of echo signals. The uniformity or linearity of the gradient field directly impacts the quality and distortion level of MRI images. However, traditional point measurement methods lack accuracy in assessing the linearity of gradient fields, making it difficult to provide effective parameters for image distortion correction. This paper introduced a spherical measurement-based method that involved measuring the magnetic field distribution on a sphere, followed by detailed magnetic field calculations and linearity analysis. This study, applied to assess the nonlinearity of asymmetric head gradient coils, demonstrated more comprehensive and precise results compared to point measurement methods. This advancement not only strengthens the scientific basis for the design of gradient coils but also provides more reliable parameters and methods for the accurate correction of MRI image distortions.
Magnetic Resonance Imaging/instrumentation* ; Humans ; Image Processing, Computer-Assisted/methods* ; Nonlinear Dynamics ; Magnetic Fields ; Algorithms ; Phantoms, Imaging

Objective To investigate the application value of single nucleotide polymorphism(SNP)linkage analysis based on next-generation sequencing(NGS)technology in preimplantation genetic testing(PGT)of families with autosomal recessive polycystic kidney disease(ARPKD).Methods A family with ARPKD was selected,where the female member had a pregnancy ultrasound revealing polycystic kidney in the fetus.Genetic testing showed compound heterozygous mutations of the polycystic kidney/polycystic liver disease 1 gene(PKHD1),c.10444C>T(paternal)and c.4303del(maternal),with the c.4303del mutation being reported for the first time.Targeting the coding region of the PKHD1 gene,335 high-density tightly linked SNP sites were selected in the upstream and downstream 2M regions using multiplex polymerase chain reaction(PCR)and NGS.The couple′s SNP risk haplotypes carrying gene mutations were constructed.After in vitro fertilization,blastocyst culture was performed.Trophoblastic cells obtained from the biopsy were subjected to whole-genome amplification,and NGS was used for linkage analysis and low-depth chromosomal aneuploidy screening of the embryos.Sanger sequencing was used to verify the results of embryo linkage analysis.Results Among the 6 biopsied embryos,4 were mutation-free and euploid,1 exhibited heterozygous for the mutation and mosaic while another unstable sequencing data,making it impossible to judge.One of the mutation-free and developmentally healthy euploid embryos was implanted into the maternal uterus,resulting in the full-term delivery of a healthy baby.Conclusion Application of NGS-based SNP linkage analysis in PGT can effectively blocking the vertical transmission of ARPKD within families,while avoiding abortion issues caused by aneuploid embryos.This study is also the first PGT report target-ing the PKHD1 gene c.4303del mutation.

Objective To investigate the clinical effects and pregnancy outcomes of using luteal phase long protocol and GnRH antagonist protocol in patients with polycystic ovary syndrome(PCOS)who have failed their first GnRH antagonist protocol therapy.Methods The clinical data of 163 PCOS patients who underwent IVF/ICSI-ET were retrieved.After the failure of their first GnRH antagonist protocol treatment,they were divided into two groups in the second controlled ovarian hyperstimulation(COH)cycle:Luteal phase long protocol group(n=95)and Gn-RH antagonist protocol group(n=68).A retrospective analysis and comparison of basic clinical data,clinical and laboratory indicators,and pregnancy outcomes between two groups were conducted.Results ① There was no sta-tistically significant difference in basic clinical indicators between two group except LH.② Compared the first and second cycle treatments of patients in the luteal phase long protocol group,the initiation dose of gonadotropin(Gn),total number of Gn days,total Gn usage,estradiol(E2)on the day of hCG injection,number of retrieved eggs,oocyte maturation rate,2PN fertilization rate,2PN cleavage rate,blastocyst formation rate,high-quality blas-tocyst formation rate,and moderate to severe OHSS rate were significantly higher than those in the first GnRH an-tagonist cycle(P＜0.05).The GnRH antagonist protocol group also showed similar improvements.③ The com-parison of the second COH cycle between two groups showed that the total number of Gn days,total Gn usage,and total Gn cost in the luteal phase long protocol group were significantly higher(P＜0.05),while the E2 and LH on the day of hCG injection,and the maturation rate of eggs were significantly lower than those in the GnRH antagonist protocol group(P＜0.05).However,there was no statistically significant difference in the number of retrieved eggs,2PN fertilization,2PN cleavage,blastocyst formation rate,high-quality blastocyst formation rate,and OHSS rate between the two groups;④ The comparison of fresh transplantation cycles for the second COH cycle between the two groups showed that the luteal phase long protocol fresh transplantation rate,implantation rate,clinical preg-nancy rate,and live birth rate were slightly higher than those of the GnRH antagonist protocol group,but the differ-ence was not statistically significant.Comparing the outcomes of pregnancy following the initial frozen-thawed em-bryo transfer(FET)between two groups,the biochemical pregnancy rate and clinical pregnancy rate of the GnRH antagonist protocol group were higher than those of the luteal phase long protocol group(P＜0.05).However,no significant statistical variations were found in implantation rate,live birth rate,neonatal gestational age,and birth weight.Conclusion For PCOS patients who fail the first GnRH antagonist protocol,an appropriate increase in the initiating dose and usage of Gn can achieve satisfactory pregnancy outcomes with both protocols.Compared with change to a luteal phase long protocol,reusing the GnRH antagonist protocol still maintains its long-standing advan-tages,such as shorter total Gn days,lower costs,and better patient compliance.

Objective To compare pregnancy outcomes among pregnant women undergoing cervical polypectomy during different gestational periods.Methods A total of 125 pregnant women were diagnosed with cervical polyps and underwent surgical removal.These participants were divided into the natural pregnancy group(n=71)and the in vitro fertilization and embryo transfer group(IVF-ET group,n=54).Retrospective analysis was conducted on various clinical parameters including age,gestational times,delivery times,abortion times,history of adverse preg-nancy outcomes,history of endometrial polyps,pre-polyp removal vaginal bleeding episodes,gestational age at the time of polyp removal procedure,number of polyps detected during surgery,postoperative pathology results as well as pregnancy outcomes.Results Vaginal bleeding was the most common symptom of pregnancy combined with cer-vical polyps,accounting for 111 cases(88.8％)(62 cases in the natural pregnancy group(87.32％)and 49 ca-ses in the IVF-ET group(90.74％)).Some patients had increased vaginal discharge or were found during a gyne-cological exam,accounting for 11.2％of the patients.All patients underwent cervical polypectomy during pregnan-cy,except for 9 cases of continued pregnancy(4 cases in the natural pregnancy group and 5 cases in the IVF-ET group),of which 13 had miscarriage,10 had preterm birth(6 in the natural pregnancy group and 4 in the IVF group)and 93(54 cases in natural pregnancy group,39 cases in IVF group)(74.4％)delivered at full term.Postoperative pathology was mostly inflammatory polyps(105 cases,84％),deciduous polyps(20 cases,8％)(10 cases in the natural pregnancy group and 10 cases in the IVF-ET group,14.09％and 18.52％,respective-ly).The incidence of preoperative vaginal bleeding,decidual polyp,postoperative abortion,and postoperative pre-term birth in the IVF-ET group exhibited higher rates compared to those observed in the natural pregnancy group;however,these differences did not reach statistical significance.Conclusion The cervical polypectomy procedure was performed during pregnancy for both the natural conception group and the IVF-ET group,with no significant disparity observed in pregnancy outcomes between these two cohorts.

Objective : To develop a prediction model for live birth based on the basic characters of patients after transcervical resection of adhesions (TCRA) undergoing frozen⁃thawed embryo transfer (F⁃ET) . Methods : A total of 491 cycles who went F ⁃ET after TCRA were included. The cycles were randomly divided into training (n = 347) and validation (n = 144) cohorts at 7 ∶ 3 ratio. Relevant factors of live birth were selected via logistic regression analysis based on the data from patients in the training cohort. Multivariate logistic regression analysis was used to establish a nomogram , and then this predict model was calibrated and verified. Results : Age , body mass index (BMI) , miscarriages and endometrial thickness were significantly related to the live birth. The statistical nomogram was built with the area under the ROC cu2rve for the training cohort was 0. 713 (95% CI: 0. 519 - 0. 815) , Hosmer⁃Lemeshow goodness of fit test were χ = 7. 062 , P = 0. 530 , and the slope of calibration curve was close to 1. AUC of validation cohort was 0. 609 (95% CI: 0. 660 - 0. 561) , presenting a well⁃pleasing goodness⁃of⁃fit and stability in this model. Conclusion Age , BMI , miscarriages and endometrial thickness can better predict the probability of live birth undergoing F ⁃ET after TCRA.

Objective : To analyze the data related to the clinical outcome of preimplantation genetic testing (PGT) for double frozen , double biopsied blastocysts and double frozen , once biopsied blastocysts , in order to expand the existing data and provide some guidance for the clinical value and safety of PGT for frozen⁃thawed embryos . Methods : Retrospective analysis was made on the 38 PGT cycles of frozen⁃thawed blastocysts . According to the frequency of biopsy , cases in the study were divided into two groups : double frozen , double biopsy ( DFDB) group and double frozen , single biopsy ( DFSB) group . The freezing method was vitrification . Results : There were 24 patients in DFDB group , 34 blastocysts were not diagnosed in the last PGT cycle , 32 blastocysts survived after thawing , and the survival rate of thawed blastocysts was 94. 12% . After the second biopsy of these 32 blastocysts , genetic testing was performed , and all of them were definitely diagnosed , including 15 normal blastocysts (46. 88% ) and 17 abnormal blastocysts (53 . 13% ) . There were 14 patients in DFSB . The remaining 50 blastocysts in the last ICSI cycle were thawed and all blastocysts survived after thawing . Biopsy of these 50 blastocysts and genetic analysis showed that 47 blastocysts were diagnosed , including 9 normal blastocysts (18 . 00% ) , 28 abnormal blastocysts (56. 00% ) , 10 mosaic blastocysts (20. 00% ) , and 3 undiagnosed blastocysts (6. 00% ) . In DFDB group and DFSB group , 8 patients and 5 patients transferred the normal blastocystswhich all survivedafter thawing . There were 5 clinical pregnancies and 3 clinical pregnancies , respectively . One healthy live birth was obtained respectively in each group . Conclusion Acceptable pregnancy rate can be obtained whatever DFSB or DFDB blastocyst , which is of clinical value . However , due to the small sample size , we need to expand the sample size to further explore its safety .

INTRODUCTION: Paraquat (PQ) intoxication is frequently associated with a high mortality rate. No specific treatment has been shown to reduce mortality in victims within the first 72 hours. We investigated the protective effects of rapamycin (Rapa) against PQ-induced toxicity in a zebrafish model. METHODS: To determine the maximum nonlethal concentration (MNLC) and lethal concentration 50 (LC50) of Rapa, zebrafish were treated at 2-5 days post fertilisation (dpf) and their mortality was recorded every 24 hours. At 5 dpf, the zebrafish were treated with PQ 100 µg/mL or PQ+Rapa (MNLC, 1/3 MNLC or 1/9 MNLC) for 72 hours, and the rate of survival was recorded every 24 hours. Reverse transcription-polymerase chain reaction was used to test the signalling pathway of mTOR (mammalian target of rapamycin). RESULTS: MNLC and LC50 of Rapa were determined to be 6.7 µg/mL and 28.9 µg/mL, respectively. At 48 hours, the PQ+Rapa groups had much lower mortality than the PQ group. The rates of survival of the PQ+Rapa groups were 43.33% (MNLC), 53.89% (1/3 MNLC) and 44.45% (1/9 MLNC), as compared to 19.45% in the PQ group, with the 1/3 MNLC group showing the highest rate of survival (p < 0.001). atg1 was slightly activated in the PQ group. In the PQ+Rapa groups, the expression of atg1 was markedly increased, suggesting strengthening of the autophagy process. CONCLUSION Rapa can increase the rate of survival of PQ-intoxicated zebrafish by inhibiting mTOR complex 1 and activating autophagy. Rapa could be an alternative first-line drug in the treatment of PQ poisoning.

Objective: To probe into the mechanism and interventional effects of silybin-phospholipid complex on amiodarone-induced steatosis in mice. Methods: Eight-week-old male C57BL/6 mice were divided into three groups (5 mice in each group): a control group (WT) with normal diet, a model group with amiodarone 150mg/kg/d by oral gavage (AM), and an intervention group on amiodarone 150mg/kg/d combined with silybin-phospholipid complex(AM+SILIPHOS. All mice were fed their assigned diet for one week. Then, one week later, serum alanine aminotransferase, aspartate aminotransferase, triglyceride, total cholesterol and high-density lipoprotein were detected of each group. A liver pathological change was observed by oil red O and H&E staining. Ultrastructural pathological changes of hepatocytes were observed to evaluate the intervention effect by transmission electron microscopy. RT-q PCR was used to detect the expression of peroxisome proliferator-activated receptor alpha and its regulated lipid metabolism genes CPTI, CPTII, Acot1, Acot2, ACOX, Cyp4a10 and Cyp4a14 in liver tissues. Intra-group comparison was done by paired t-test. One-way ANOVA was used for comparison between groups and semi-quantitative data were tested using Mann-Whitney U test. Results: Oil Red O and H&E staining results of liver tissue in the intervention group showed that intrahepatic steatosis was significantly reduced when compared to model group. Transmission electron microscopy showed that the model group had pyknotic nuclei, mitochondrial swelling, structural damage, and lysosomal degradation whereas the intervention group had hepatic nucleus without pyknosis, reduced mitochondrial swelling and slight structural damage than that of model group. RT-q PCR results showed that the expression of peroxisome proliferator-activated receptor alpha, CPTI, CPTII, Acot1, Acot2, ACOX, Cyp4a10 and Cyp4a14 were increased in the model group but the expression of CPTI, Cyp4a14, Acot1 and peroxisome proliferator-activated receptor alpha were decreased in the intervention group (P < 0.05). Conclusion Silybin-phospholipid complex can alleviate amiodarone-induced steatosis, and its mechanism may play a role in protecting mitochondrial function and regulating fatty acid metabolism. Thus, silybin-phospholipid complex has potential intervention effect on amiodarone-induced fatty liver.

Objective: To explore the changes of the peripheral invariant natural killer T (iNKT) cells in patients with human immunodeficiency virus (HIV) infection. Methods: A total of 101 patients with HIV infection including 52 asymptomatic patients and 49 acquired immunodeficiency syndrome (AIDS) patients were enrolled in the study from June 2016 to July 2017. Flow cytometry was used to detect iNKT cells, CD4⁺ T cells and CD8⁺ T cells, and the relationship among them and HIV RNA was studied. At same time, 12 healthy persons were enrolled as control group. T test or variance analysis, rank sum test, Chi-square test and Fisher exact test were used for statistical analysis. Results: In HIV infected asymptomatic patients, AIDS patients and healthy controls, iNKT cells were 0.135% (0.066%, 0.228%), 0.058% (0.034%, 0.100%) and 0.385% (0.205%, 0.600%), respectively, and the difference was statistical significant (Z=40.113, P<0.01). CD4⁺ T cell counts in the three groups were (340.82±119.26) cells/μL, (72.73±61.84) cells/μL and (555.17±229.43) cells/μL, respectively, and the difference was statistical significant (t=113.79, P<0.01); CD8⁺ T cell counts in the three groups were (842.29±423.68) cells/μL, (540.43±257.85) cells/μL and (875.92±516.45) cells/μL, respectively, and the difference was statistical significant (t=9.423, P<0.01). Ratios of CD4⁺ /CD8⁺ T cells in the three groups were 0.490 (0.240, 0.695), 0.120 (0.030, 0.210) and 0.600 (0.475, 0.895), respectively, and the difference was statistical significant (Z=53.603, P<0.01). iNKT cell counts in patients with or without hepatitis B virus infection, pneumocystis pneumonia, oral mold infection, treponema pallidum, latent tuberculosis or EB virus infection were not significantly different (Z=0.244, 2.325, 2.393, 0.168, 1.183 and 0.454, respectively, all P>0.05). There were correlations between iNKT cells and CD4⁺ T cells, CD4⁺ /CD8⁺ T cells (r=0.513 and 0.261, respectively, both P<0.05), and no relationship was found between iNKT cells and CD8⁺ T cells (r=0.155, P=0.126). In HIV infected asymptomatic patients and AIDS patients, iNKT cells was not associated with HIV RNA (r=-0.113 and -0.111, respectively, both P>0.05). Conclusions The level of peripheral iNKT cells in HIV infected patients decreases with the disease progression. To certain extent, iNKT cells can reflect the severity of immune damaging in HIV infected patients.

Background:Activation of hepatic stellate cells( HSCs)plays a pivotal role in development of liver fibrosis. Interleukin-17(IL-17)is the most important effector of T helper 17(Th17)cells that causes inflammatory cell infiltration and tissue damage. Preliminary studies showed that the number of IL-17-positive cells in liver tissue was positively correlated with the severity of liver fibrosis in patients with chronic hepatitis B and autoimmune hepatitis. However,the mechanism of IL-17 in liver fibrosis is not yet clarified. Aims:To investigate the effect of IL-17 on activation of human HSC cell line LX2 and collagen expression. Methods:Human HSC cell line LX2 was treated with different concentrations of IL-17. Viability of LX2 cells was measured by CCK-8 assay. mRNA expressions of α-smooth muscle actin(α-SMA), type Ⅰ collagen(Col-Ⅰ)and Col-Ⅲ were determined by real-time PCR. Protein expressions of α-SMA、Col-Ⅰ and Col-Ⅲ were detected by immunofluorescence. Results: Viability of LX2 cells increased with the increase of IL-17 concentration,but no significant differences were seen between any two groups(P > 0. 05). mRNA expressions of α-SMA, Col-Ⅰ and Col-Ⅲ in IL-17 treatment group(100 ng/ mL)were significantly higher than those in blank control group(P <0. 05). With the increase of IL-17 concentration,protein expressions of α-SMA,Col-Ⅰ and Col-Ⅲ gradually increased. Conclusions:IL-17 can promote the activation of HSCs and expressions of Col-Ⅰ and Col-Ⅲ,thereby contributing to the development of liver fibrosis.