槲皮素磁性分子印记聚合物的制备及其吸附性能

以槲皮素(Qu)为模板分子、N-乙烯基吡咯烷酮(NVP)和丙烯酸(AA)为功能单体、N,N'-亚甲基双丙烯酰胺(MBA)为交联剂、H₂O₂-Vc为引发剂、KH570修饰的Fe₃O₄纳米颗粒为磁性载体,借助表面分子印迹技术制备了能够对Qu进行特异性识别的槲皮素磁性分子印迹聚合物(Qu-MMIPs)。利用X射线衍射仪(XRD)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FT-IR)、振动样品磁强计(VSM)和紫外-可见分光光度计(UV-Vis)对样品进行了结构和性能表征。结果表明:Fe₃O₄磁性载体表面已成功包覆了分子印迹聚合物。与化学组成相同的磁性非印迹聚合物(Qu-MNIPs)相比,Qu-MMIPs对Qu有较高的吸附选择性。静态吸附平衡实验和Scatchard分析结果表明,Qu-MMIPs中存在两类不同的结合位点,平衡解离常数分别为1.646×10^-6mol/L和6.387×10^-6mol/L,最大吸附量分别为23.041 mg/g和29.923 mg/g。     

中空纤维膜反应器结合芬顿试剂脱除燃煤烟气中的Hg0

将中空纤维膜反应器和芬顿试剂结合脱除烟气中的Hg⁰。研究了不同参数以及SO₂、NO和O₂等杂质气体对Hg⁰脱除的影响。结果表明：随着H₂O₂浓度、Fe²⁺浓度、溶液初始pH和温度的增加,Hg⁰脱除率先增加后降低,其最佳工作条件是H₂O₂浓度为6 mmol/L,Fe²⁺浓度为9 mmol/L,溶液初始pH为2.5,温度为20℃;增大液气比和通过减小气相流量增大停留时间均对Hg⁰脱除有增强作用,当液气比超过0.11时,Hg⁰的脱除率不再增加;当气相流量为0.6 L/min时,Hg⁰脱除率超过85%;SO₂、NO对Hg⁰的脱除有抑制作用,O₂对Hg⁰的脱除几乎没有影响;还测定出温度20℃下中空纤维膜反应器的比相界面积a=270.29 m^-1和传质动力学参数k_L=8.13×10^-4 m/s,k_G=0.786×10^-6 mol/（m²·s·Pa）。     

硫化氢供体型美金刚衍生物的合成及其活性

H₂S具有保护缺血再灌注损伤的神经元、显著降低脑梗死面积的作用,但高浓度H₂S产生神经毒性。N-甲基-D-天冬氨酸(NMDA)受体拮抗剂美金刚可以降低高浓度H₂S引起的神经毒性。将硫化氢缓释供体5-对羟基苯基-1,2-二硫杂环戊烯-3-硫酮(ADT-OH)与美金刚通过烷烃连接臂拼合,设计了9个结构全新的化合物I₁~I₉,以ADT-OH为原料,经过4步反应得到目标化合物,其化学结构经¹H NMR、¹³C NMR和HRMS确证。利用MTT法评价不同浓度目标化合物对谷氨酸损伤的HT-22细胞的影响,结果发现,该类化合物在1 μmol/L时能明显提高受损HT-22细胞的生存率(P<0.01),对于谷氨酸诱导损伤的神经元细胞具有较好的保护作用。     

喹喔啉与二辛基芴交替共聚物的合成及其酸致变色性能

通过还原4,7-二溴-2,1,3-苯并噻二唑制备2,5-二溴邻苯二胺,并分别与1,10-邻菲罗啉-5,6-二酮、苊醌、菲醌和联苯甲酰缩合反应,制备了4种单喹喔啉衍生物（M1、M2、M3、M4）。在二乙酸钯（Pd（CH₃COO）₂）和配体三环己基膦的催化下,通过Suzuki反应将2,7-二（4,4,5,5-四甲基-1,3,2-二氧杂硼酸烷）-9,9-二辛基芴（M5）分别与M1、M2、M3、M4交替共聚制得4种聚合物（P1、P2、P3、P4）。通过FT-IR和¹H-NMR等测试方法表征所有单体及聚合物的结构。通过UV-Vis光谱和荧光光谱探讨了4种聚合物在CHCl₃溶液中本征态的光谱性能,以及相应聚合物的CHCl₃溶液被低浓度三氟乙酸（TFA）质子化时的光学性能。结果显示,4种聚合物对低浓度TFA有良好的敏感性。聚合物P1与2.17×10^-7 mol/L的TFA作用时,P1的CHCl₃溶液明显变色。聚合物P2~P4的CHCl₃溶液与4.32×10^-3 mol/L的TFA作用时,溶液颜色发生变化,与此同时在UV-Vis光谱上500~800 nm处出现新的吸收带。同时,4种交替共聚物的CHCl₃溶液具有较好的荧光性能,当溶液中加入低浓度的TFA时,即在4种聚合物的CHCl₃溶液中分别加入7.0×10^-10、1.73×10^-6、7.5×10^-7 mol/L和4.0×10^-6 mol/L的TFA时,其荧光发射强度明显减弱。     

参麦注射液抗氧化活性体外实验研究

[目的] 系统研究参麦注射液体外抗氧化性能。[方法] 采用铁还原抗氧化能力 （FRAP）法、1,1-二苯基-2-三硝基苯肼（DPPH）自由基清除法、一氧化氮（NO）自由基清除法、过氧化氢（H₂O₂）清除法、亚铁（Fe²⁺）离子螯合法分别测试不同稀释倍率参麦注射液的总抗氧化能力、DPPH·清除活性、NO·清除活性、H₂O₂清除活性和Fe²⁺离子螯合活性,并将结果与0.1mg/mL 2,6-二叔丁基对甲酚（BHT）、10 mmol/L水溶性维生素E（Trolox）和10%柠檬酸的结果进行比较。[结果] 参麦注射液具有一定的体外抗氧化能力,总抗氧化能力和对自由基清除活性均呈浓度正依赖性;10倍稀释参麦注射液总抗氧化能力显著低于BHT和Trolox （P<0.01）,但高于柠檬酸（P<0.01）;参麦注射液对不同自由基清除能力存在差异,其强弱顺序为：NO·[（54.4±6.6）%] > Fe²⁺离子螯[（42.6±3.2）%] > DPPH·[（36.2±2.8）%] > H₂O₂[（23.5±1.2）%]。[结论] 参麦注射液体外抗氧化活性研究将为其抗氧化药理学机制提供了实验依据。     

Nb2O5掺杂对SrTiO3陶瓷显微结构和微波介电损耗的影响

采用无压烧结工艺制备了Nb₂O₅掺杂SrTiO₃陶瓷,研究了Nb₂O₅掺杂量对SrTiO₃陶瓷相组成、显微结构和微波介电损耗的影响。结果表明：Nb₂O₅掺杂对SrTiO₃陶瓷的相结构没有产生明显的影响,但会在一定程度上阻碍样品的致密化,同时促进晶粒的生长。随着Nb₂O₅掺杂量的增加,SrTiO₃陶瓷的介电常数从296逐渐下降至230左右,温度系数从1.714×10^-3℃^-1逐渐下降至1.629×10^-3℃^-1,Q×f值则先急剧升高,之后又慢慢下降。当Nb₂O₅掺杂量为0.15%（质量分数,下同）时,SrTiO₃陶瓷样品的介电损耗最低,Q×f可达6 281 GHz,大约是纯SrTiO₃（1 145 GHz）陶瓷样品的5.5倍（此时介电常数约为270,温度系数约为1.684×10^-3℃^-1）。此外,对材料显微结构、介电常数、温度系数特别是介电损耗变化的原因进行了分析。     

P(St-co-MMA)微球表面包覆磁性氧化石墨烯的制备与表征

以单分散的苯乙烯-甲基丙烯酸甲酯共聚物(P(St-co-MMA))微球为载体,FeSO₄·7H₂O和FeCl₃·6H₂O为铁源,NaOH为沉淀剂,在氧化石墨烯(GO)存在下,利用反相共沉淀法通过原位复合技术在P(St-co-MMA)微球表面包覆磁性氧化石墨烯(P(St-co-MMA)/Fe₃O₄/GO)。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FT-IR)、X射线衍射仪(XRD)、振动样品磁强计(VSM)和氮吸附-脱附等温线对P(St-co-MMA)/Fe₃O₄/GO样品的结构和性能进行表征分析。研究结果表明:纳米级的磁性氧化石墨烯成功地负载在了微米级的共聚物P(St-co-MMA)表面,所制备的P(St-co-MMA)/Fe₃O₄/GO微纳米复合物平均孔径为14.55 nm,孔体积为0.204 2 cm³/g,比表面积为56.14 m²/g。该复合物具有超顺磁性和良好的磁响应性,能够满足磁分离的要求。     

富氢水对体外培养甲状腺相关眼病患者眼眶成纤维细胞氧化应激的影响

目的 探讨富氢水对甲状腺相关眼病（TAO）的抗氧化应激作用。方法 取TAO患者眼眶脂肪结缔组织的眼眶成纤维细胞进行体外培养,用不同浓度的过氧化氢（H₂O₂）处理细胞18 h后,用CCK-8法检测细胞增殖能力以确定合适的H₂O₂浓度。将细胞为4组：空白组（正常培养）、H₂O₂组（H₂O₂处理18 h）、富氢水+H₂O₂组（富氢水处理72 h的同时用H₂O₂处理18 h）、地塞米松+H₂O₂组（1 μmol/L地塞米松处理72 h的同时用H₂O₂处理18 h）。用流式细胞术检测各组细胞活性氧（ROS）荧光强度,用ELISA检测细胞培养液中丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）的含量。结果 TAO患者眼眶成纤维细胞体外培养成功。H₂O₂浓度越高对TAO患者眼眶成纤维细胞增殖能力的抑制效果越明显,本实验最终选取的H₂O₂浓度为100 μmol/L。培养TAO患者眼眶成纤维细胞72 h后,空白组、H₂O₂组、富氢水+H₂O₂组、地塞米松+H₂O₂组细胞培养液中MDA、SOD、GSH-Px的含量和细胞ROS荧光强度分别为（1.63±0.29）、（5.06±0.24）、（3.94±0.29）、（2.34±0.24）nmol/mL,（10.51±0.32）、（2.41±0.23）、（5.58±0.29）、（7.98±0.15）U/mL,（107.79±1.06）、（21.07±0.92）、（49.19±6.75）、（76.33±4.70）U/mL和18 275.82±521.05、92 524.81±2 097.01、54 460.87±572.64、35 961.37±540.61,统计分析发现富氢水和地塞米松均可抑制H₂O₂处理后眼眶成纤维细胞的氧化应激（P均<0.01）,且地塞米松的抑制效果较富氢水更明显（P均<0.01）。结论 氢分子可能通过抗氧化应激对TAO发挥治疗作用。     

二噻吩基喹喔啉的氧化聚合及其酸致变色性能

以双三苯基膦二氯化钯(Pd(PPh₃)₂Cl₂)为催化剂,通过Stille偶联反应合成二噻吩基苯并噻二唑,将其作为原料分别与5,6二酮-1,10-邻菲罗啉、菲醌、苊醌和联苯甲酰反应,分别制备了4个二噻吩基喹喔啉衍生物(P1、P2、P3、P4)。以无水FeCl₃作为氧化剂,4个二噻吩基喹喔啉衍生物通过溶液氧化聚合为4个均聚物。用FT-IR和¹H-NMR等测试手段对单体及聚合物的结构进行了表征。通过UV-Vis-NIR光谱和荧光光谱法,研究了聚合物本征态以及与不同浓度的三氟乙酸(TFA)作用时的光学性能。结果显示,聚合物P2~P4对低浓度TFA具有良好的敏感性,其中聚合物P2与8.0×10^-4 mol/L的TFA作用后,P2的CHCl₃溶液的颜色发生明显变化,并且其UV-Vis-NIR光谱在600~1 100 nm出现新的宽吸收带。P2~P4具有一定的荧光性能,且向溶液中加入一定浓度TFA时,聚合物荧光强度减弱且发射波长发生蓝移,其中聚合物P2与8.0×10^-6 mol/L的TFA作用时其荧光发射强度明显减弱。     

18F-FDG PET-CT与乳腺癌新辅助化疗疗效中的关联性分析

目的 本研究旨在探讨¹⁸F-FDG PET-CT与乳腺癌新辅助化疗疗效的关联性。方法 2014年1月~2015年12月,收集笔者医院收治的行新辅助化疗的乳腺癌患者98例。前瞻性分析¹⁸F-FDG PET-CT与乳腺癌新辅助化疗疗效的关联性。结果 与病理无效组相比,病理有效组患者SUV_max0显著增加（9.54±3.11 vs 6.12±3.21,P=0.015）;SUV_max1变化率显著增加（53%±17% vs 29%±11%,P=0.000）;SUV_max2变化率显著增加（61%±21% vs 34%±12%,P=0.000）。与未pCR组相比,pCR组患者SUV_max0显著增加（10.54±4.11 vs 5.87±2.21,P=0.000）;SUV_max1变化率显著增加（57%±17% vs 28%±10%,P=0.000）;SUV_max2变化率显著增加（64%±23% vs 33%±11%,P=0.000）。结论 ¹⁸F-FDG PET-CT可作为评价乳腺癌新辅助化疗效果的一种影像学方式,值得临床进一步推广。     

Value of D-Dimers in patients with acute aortic dissection

Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P ＜ 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (＞0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P ＜0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P ＜ 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.     

Research of combined liver-kidney transplantation model in rats

Objective： To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods： SD rats served as both donors and recipients. 4℃ sodium lactate Ringer＇s was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava （IVC） inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results： Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion： This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.     

BLOOD PRESSURE CHANGE WITH AGE IN SALT-SENSITIVE TEENAGERS

Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P＜ 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P＜ 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure.     

安心颗粒对急诊经皮冠状动脉介入术后生活质量影响的研究

目的：评价使用安心颗粒对急诊经皮冠状动脉介入术（PPCI）术后生活质量的影响.方法：将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组（术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次）和对照组（仅接受基础药物治疗）.所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表（MIDAS）、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果：入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异（P＞0.05）;出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低（P＜0.05）;组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低（P＜0.05）.两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血（P＞0.05）.两组发生轻度血小板减少症的患者数比较无差异（P＞0.05）.结论：PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.     

The comparative studies of the influences of Urapidil and Nicardipine on sino-atrial node function, atrio-ventricular node function and hemodynamics

Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P＜0.01);the MAP decreased(P＜0.01)and the HR increased drastically(P＜0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.     

Expression of OPGmRNA and ODFmRNA in the patients of hip fracture due to osteoporosis

Objective：To investigate the gene expression of osteoprotegerin（OPG） and osteoclast differentiation factor（ODF） in the bone tissue of patients with hip fracture due to osteoporosis. Methods：OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers（over 50 years old） with hip fracture（Observer Group） and 30 cases of hip facture sufferers with no osteoporosis（Control group） were analyzed with the Semi-Quantitative RT-PCR method. Results：The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion：Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.     

The clinicopathological and immuohistochemical analysis of solid-pseudopapillary tumor of the pancreas： report of 9 cases

Objective：To investigate the clinical features, pathological characteristics and immunophenotype of solid-pseudopapillary tumor of the pancreas（SPTP）. Methods：Nine surgically treated cases of SPTP were retrospectively reviewed. Hematoxylin and Eosin（HE） staining and immunohistochemical staining were used to analyze all cases, and the general clinical data was collected. Results：Six patients were asymptomatic except for a palpable mass. Two patients complained of vague-epigastric pain. One patient appeared jaundice. The tumor was encapsulated and solid tissues alternately with cystic tissues. Histologically, the histological structure of solid portion was pseudopapillary with a fibrovascular core. Tumor cells were uniform and medium-sized which were arranged in sheets ets or nests or pseudopapillary patterns. Immunohistochemical studies demonstrated that SPTP proved positive in vimentin（9/9 cases）, AAT（9/9 cases）, NSE（9/9 cases）, ACT（7/9 cases）, CK20（2/9 cases）, CgA（1/9 cases）, S-100（3/gcases）, PR（4/gcases）, Syn（3/9 cases） and CD56（5/9cases）, negative in CEA and ER. Conclusion：SPTP is a tumor predominantly occurring in young women frequently without special symptoms. This tumor has various characteristical histological patterns with different immunophenotype.     

Dynamic Changes in Serum Estradiol and Progesterone levels in Patients of Premenstrual Syndrome with Adverse Flow of Liver-qi

Objective:To probe into the influence of changes of ovarian hormones on the pathogenesis of the specific sub-type premenstrual syndrome(PMS)and reveal partial microcosmic mechanisms of adverse flow of liver-qi.Methods:Estradiol(E2)and progesterone(P)levels in serum were determined at different phases of menstrual cycle by radioimmunoassay.Results:In the group of PMS with adverse flow of liver-qi.the secretive peak value Of E2 and P at the follicular phase significantly decreased,and the secretive peak value at the luteal phase did not come into being.Conclusions:Low E2 and P secretive peak at the follicular phase and absence of secretive peak at the luteal phase is one of the microcosmic mechanisms of PMS with adverse flow of liver-qi.One of the pathophysiologic mechanisms of specific sub-type PMS is probably the continuous low level of E2and P.     

Real-time Three-dimensional Echocardiography in Assessment of Left Ventricular and Right Ventricular Volumes

Real-time three-dimensional echocardiography (RT3DE)is a new ultrasound technique that enables dynamic threedimensional visualization and quantification of the heart in real time. Investigation of feasibility and methodology of RT3DE in determining left ventricular (LV) and right ventricular (RV) volumes, RT3DE was performed in 35 normal adults using Philips SONOS 7500 system with a 2-4 MHz matrix array transducer. The 60°×60° "pyramid" volume database was obtained and analyzed on a TomTec echo workstation. Both LV and RV volumes were calculated with four 3DE methods (i.e. apical 2, 4, 8, and 16-plane) through manually tracing ventricular endocardial borders in end diastole and end systole. Stroke volumes were then calculated. LV volume was also measured by 2DE Simpson's rule using GE VIVID 7 ultrasound machine.     

SCREENING FOR A 21-CHROMOSOME ABNORMALITY IN PREIMPLANTED EMBRYOS OF ELDERLY WOMEN

Increasing maternal age is the only etiological factor unequivocally linked to Down's syndrome in humans. The occurrence rate of newborns with Down's syndrome is about 1/220 in women over 35 years old. However, the occurrence rate in embryos fertilized in vitro, of the elder woman is unclear. Using FISH we screened the number of chromosome 21 in preimplanted embryos of 5 elderly women (average age, 38.4 years) to study the feasibility and necessity of screening trisomy 21 in embryos in patients over 35 years old at the in vitro fertilization (IVF) center.