[Establishment method and significance of birthweight curve and reference in single center]

Objective: To establish neonatal birthweight percentile curves based on single-center cohort database using different methods, compare them with the current national birthweight curves and discuss the appropriateness and significance of single-center birthweight standard. Methods: Based on a prospective first-trimester screening cohort at Nanjing Drum Tower Hospital from January 2017 to February 2022, the generalized additive models for location, scale and shape (GAMLSS) and semi-customized method were applied to generate local birthweight percentile curves (hereinafter referred to as the local GAMLSS curves, semi-customized curves) for 3 894 cases who were at low risk of small for gestation age (SGA) and large for gestation age (LGA). Infants were categorized as SGA (birth weight<10th centile) by both semi-customized and local GAMLSS curves, semi-customized curves only, or not SGA (met neither criteria). The incidence of adverse perinatal outcome between different groups was compared. The same method was used to compare the semi-customized curves with the Chinese national birthweight curves (established by GAMLSS method as well, hereinafter referred to as the national GAMLSS curves). Results: (1) Among the 7 044 live births, 404 (5.74%, 404/7 044), 774 (10.99%, 774/7 044) and 868 (12.32%, 868/7 044) cases were diagnosed as SGA according to the national GAMLSS curves, the local GAMLSS curves and the semi-customized curves respectively. The birth weight of the 10th percentile of the semi-customized curves was higher than that of the local GAMLSS curves and the national GAMLSS curves at all gestational age. (2) When comparing semi-customized curves and the local GAMLSS curves, the incidence of admission to neonatal intensive care unit (NICU) for more than 24 hours of infants identified as SGA by semi-customized curves only (94 cases) and both semi-customized and local GAMLSS curves (774 cases) was 10.64% (10/94) and 5.68% (44/774) respectively, both significantly higher than that in non SGA group [6 176 cases, 1.34% (83/6 176); P<0.001]. The incidence of preeclampsia, pregnancy<34 weeks, and pregnancy<37 weeks of infants identified as SGA by the semi-customized curves only and both semi-customized and local GAMLSS curves was 12.77% (12/94) and 9.43% (73/774), 9.57% (9/94) and 2.71% (21/774), 24.47% (23/94) and 7.24% (56/774) respectively, which were significantly higher than those of the non SGA group [4.37% (270/6 176), 0.83% (51/6 176), 4.23% (261/6 176); all P<0.001]. (3) When comparing semi-customized curves and the national GAMLSS curves, the incidence of admission to NICU for more than 24 hours of infants identified as SGA by semi-customized curves only (464 cases) and both semi-customized and national GAMLSS curves (404 cases) was 5.60% (26/464) and 6.93% (28/404) respectively, both significantly higher than that in non SGA group [6 176 cases, 1.34% (83/6 176); all P<0.001]. The incidence of emergency cesarean section or forceps delivery for non-reassuring fetal status (NRFS) in infants identified as SGA by semi-customized curves only and both semi-customized and national GAMLSS curves was 4.96% (23/464) and 12.38% (50/404), both significantly higher than that in the non SGA group [2.57% (159/6 176); all P<0.001]. The incidence of preeclampsia, pregnancy<34 weeks, and pregnancy<37 weeks in the semi-customized curves only group and both semi-customized and national GAMLSS curves group was 8.84% (41/464) and 10.89% (44/404), 4.31% (20/464) and 2.48% (10/404), 10.56% (49/464) and 7.43% (30/404) respectively, all significantly higher than those in the non SGA group [4.37% (270/6 176), 0.83% (51/6 176), 4.23% (261/6 176); all P<0.001]. Conclusion: Compared with the national GAMLSS birthweight curves and the local GAMLSS curves, the birth weight curves established by semi-customized method based on our single center database is in line with our center' SGA screening, which is helpful to identify and strengthen the management of high-risk infants.

[Treatment and prognosis analysis of 488 patients with FIGO 2018 stage Ⅲc squamous cervical cancer]

Objective: To analyze the treatment and prognosis of patients with International Federation of Gynecology and Obstetrics (FIGO) 2018 stage Ⅲc cervical squamous cell carcinoma. Methods: A total of 488 patients at Zhejiang Cancer Hospital between May, 2013 to May, 2015 were enrolled. The clinical characteristics and prognosis were compared according to the treatment mode (surgery combined with postoperative chemoradiotherapy vs radical concurrent chemoradiotherapy). The median follow-up time was (96±12) months ( range time from 84 to 108 months). Results: (1) The data were divided into surgery combined with chemoradiotherapy group (surgery group) and concurrent chemoradiotherapy group (radiotherapy group), including 324 cases in the surgery group and 164 cases in the radiotherapy group. There were significant differences in Eastern Cooperation Oncology Group (ECOG) score, FIGO 2018 stage, large tumors (≥4 cm), total treatment time and total treatment cost between the two groups (all P<0.01). (2) Prognosis: ① for stage Ⅲc1 patients, there were 299 patients in the surgery group with 250 patients survived (83.6%). In the radiotherapy group, 74 patients survived (52.9%). The difference of survival rates between the two groups was statistically significant (P<0.001). For stage Ⅲc2 patients, there were 25 patients in surgery group with 12 patients survived (48.0%). In the radiotherapy group, there were 24 cases, 8 cases survived, the survival rate was 33.3%. There was no significant difference between the two groups (P=0.296). ② For patients with large tumors (≥4 cm) in the surgery group, there were 138 patients in the Ⅲc1 group with 112 patients survived (81.2%); in the radiotherapy group, there were 108 cases with 56 cases survived (51.9%). The difference between the two groups was statistically significant (P<0.001). Large tumors accounted for 46.2% (138/299) vs 77.1% (108/140) in the surgery group and radiotherapy group. The difference between the two groups was statistically significant (P<0.001). Further stratified analysis, a total of 46 patients with large tumors of FIGO 2009 stage Ⅱb in the radiotherapy group were extracted, and the survival rate was 67.4%, there was no significant difference compared with the surgery group (81.2%; P=0.052). ③ Of 126 patients with common iliac lymph node, 83 patients survived, with a survival rate of 65.9% (83/126). In the surgery group, 48 patients survived and 17 died, with a survival rate of 73.8%. In the radiotherapy group, 35 patients survived and 26 died, with a survival rate of 57.4%. There were no significant difference between the two groups (P=0.051). (3) Side effects: the incidence of lymphocysts and intestinal obstruction in the surgery group were higher than those in the radiotherapy group, and the incidence of ureteral obstruction and acute and chronic radiation enteritis were lower than those in the radiotherapy group, and there were statistically significant differences (all P<0.01). Conclusions: For stage Ⅲc1 patients who meet the conditions for surgery, surgery combined with postoperative adjuvant chemoradiotherapy and radical chemoradiotherapy are acceptable treatment methods regardless of pelvic lymph node metastasis (excluding common iliac lymph node metastasis), even if the maximum diameter of the tumor is ≥4 cm. For patients with common iliac lymph node metastasis and stage Ⅲc2, there is no significant difference in the survival rate between the two treatment methods. Based on the duration of treatment and economic considerations, concurrent chemoradiotherapy is recommended for the patients.

[Outcomes and prognosis of radical surgery in patients with stageⅠb2 and Ⅱa2 cervical squamous cell carcinoma]

Objective: To evaluate the survival, complications and prognostic factors in patients with stageⅠb2 and Ⅱa2 cervical squamous cell carcinoma treated by primarily radical surgery with or without postoperative adjuvant therapy. Methods: The clinical and pathological data of patients with stageⅠb2 and Ⅱa2 cervical squamous cell carcinoma treated in the Cancer Hospital of the University of Chinese Academy of Sciences from January 2015 to January 2018 were retrospectively analyzed. All patients underwent Querleu-Morrow classification (Q-M classification) C2 radical surgery, including extensive hysterectomy+pelvic lymphadenectomy with or without adjuvant therapy based on postoperative risk factors. Survival rate was calculated by Kaplan-Meier method and survival curve was drawn. Univariate analysis was performed by using the log-rank test to analyze the clinicopathological factors related to the prognosis of patients. Multivariate analysis was performed by using Cox regression method to analyze independent risk factors affecting survival prognosis. Results: (1) The median age of 643 patients with cervical squamous cell carcinoma was 50 years old (45-58 years old). Clinical stage: 260 cases (40.4%, 260/643) of stage Ⅰb2, 383 cases (59.6%, 383/643) of stage Ⅱa2. (2) Among 643 cases underwent Q-M classification C2 surgery, 574 cases (89.3%, 574/643) of them received adjuvant therapy and 184 cases (28.6%, 184/643) of them had grade 3-4 complications after treatment, including 134 cases (20.8%, 134/643) early complications and 66 cases (10.3%, 66/643) late complications. The incidence of grade 3-4 complications in 574 patients received postoperative adjuvant therapy was 30.1% (173/574), which was significantly different from that in 69 patients who received surgery alone (15.9%, 11/69; χ²=6.08, P=0.014). (3) All 643 cases were followed up, and the median follow-up time was 40 months (3-76 months). During the follow-up period, 117 cases (18.2%, 117/643) recurred, including 45 cases (7.0%, 45/643) of local recurrence, 54 cases (8.4%, 54/643) of distant metastasis, and 18 cases (2.8%, 18/643) of local recurrence and distant metastasis. The 5-year progression-free survival (PFS) and 5-year overall survival (OS) rates of patients with stage Ⅰb2 and Ⅱa2 cervical squamous cell carcinoma were 79.9% and 85.5%, respectively. Univariate analysis showed that pelvic lymph node metastasis, para-aortic lymph node metastasis, deep stromal infiltration, and lymph-vascular space invasion were significantly associated with 5-year PFS in patients with stage Ⅰb2 and Ⅱa2 cervical squamous cell carcinoma (all P<0.05). The maximum diameter of tumor, pelvic lymph node metastasis and para-aortic lymph node metastasis were significantly associated with the 5-year OS of cervical squamous cell carcinoma in stages Ⅰb2 and Ⅱa2 (all P<0.05). Multivariate analysis showed that pelvic lymph node metastasis and para-aortic lymph node metastasis were independent factors affecting 5-year PFS and 5-year OS in patients with stage Ⅰb2 and Ⅱa2 cervical squamous cell carcinoma (all P<0.01). Conclusion: Radical surgery is a feasible and effective primary treatment for stagesⅠb2 and Ⅱa2 cervical squamous cell carcinoma, with a high 5-year survival rate and an acceptable complication rate.

Methylene-bridge tryptophan fatty acylation regulates PI3K-AKT signaling and glucose uptake

Protein fatty acylation regulates numerous cell signaling pathways. Polyunsaturated fatty acids (PUFAs) exert a plethora of physiological effects, including cell signaling regulation, with underlying mechanisms to be fully understood. Herein, we report that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) regulate PI3K-AKT signaling by modifying PDK1 and AKT2. DHA-administered mice exhibit altered phosphorylation of proteins in signaling pathways. Methylene bridge-containing DHA/EPA acylate δ1 carbon of tryptophan 448/543 in PDK1 and tryptophan 414 in AKT2 via free radical pathway, recruit both the proteins to the cytoplasmic membrane, and activate PI3K signaling and glucose uptake in a tryptophan acylation-dependent but insulin-independent manner in cultured cells and in mice. DHA/EPA deplete cytosolic PDK1 and AKT2 and induce insulin resistance. Akt2 knockout in mice abrogates DHA/EPA-induced PI3K-AKT signaling. Our results identify PUFA's methylene bridge tryptophan acylation, a protein fatty acylation that regulates cell signaling and may underlie multifaceted effects of methylene-bridge-containing PUFAs.

[Association between gestational blood pressure and pregnancy induced hypertension or pre-eclampsia]

Objective: To construct the gestational-age-specific blood pressure curve and percentile blood pressure values of pregnant women in Jiangsu Province, and to explore the clinic significance of the blood pressure changes in women whose blood pressure was less than 140/90 mmHg (1 mmHg=0.133 kPa) in each trimester and eventually developed pregnancy induced hypertension (PIH) or pre-eclampsia (PE). Methods: A prospective longitudinal cohort during pregnancy was built. Singleton pregnant women in the first trimester (11-13⁺⁶ weeks) were recruited from July 2017 to September 2020 in Nanjing Drum Tower Hospital, and were followed up in the second trimester (19-23⁺⁶ weeks), the third trimester (30-33⁺⁶ weeks) and approaching the expected date of delivery (35-38⁺⁶ weeks). The Viewpoint 6.0 software was used to record pregnancy-related information. The blood pressure was measured by standard methods in our clinic. Least mean square (LMS) function was performed to fit the gestational-age-specific blood pressure curve and percentile blood pressure values were calculated at every follow-up time point. Logistic regression was applied to calculate the OR for the groups with blood pressure ≥95th percentile (P₉₅). Results: There were 3 728 singleton pregnant women invited in this study, including 3 490 normal pregnant women (93.62%, 3 490/3 728), and 238 pregnant women with PIH or PE (6.38%, 238/3 728). Gestational-age-specific blood pressure curve showed that systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) decreased in the second trimester, compared with those in the first and the third trimester, however the fluctuation of blood pressure was low, but regardless of the gestational age, P₉₅ of SBP, DBP and MAP increased by 14, 11 and 11 mmHg respectively, compared with 50th percentile (P₅₀). In the first trimester, the risk of developing PIH or PE finally in pregnant women with blood pressure ≥P₉₅ was 4.36-fold (95%CI: 2.99-6.35) for SBP than women with SBP<P₉₅, 5.22-fold (95%CI: 3.65-7.46) for DBP and 5.14-fold (95%CI: 3.61-7.32) for MAP. When approaching the expected date of delivery, the corresponding risks of the women with blood pressure ≥P₉₅ were 16.76 times, 27.45 and 27.31 times respectively than those of the women with blood pressure <P₉₅. In the first trimester, every 1 mmHg elevation of SBP the risk developing PIH or PE increased by 24% (OR=1.24, 95%CI: 1.15-1.33), 44% (OR=1.44, 95%CI: 1.31-1.59) for DBP and 47% (OR=1.47, 95%CI: 1.33-1.61) for MAP, respectively. The risk in the second trimester was similar to that in the first trimester, and in the third trimester, the risk was further increased. When approaching the expected date of delivery, DBP or MAP increased by 1 mmHg, the risk developing PIH or PE was double; while SBP increased by 1 mmHg, the risk increased by 58%. The areas under the receiver operator characteristic curves of SBP, DBP and MAP were similar for predicting PIH or PE, and the predictive efficiency were all poor. Conclusions: Construction of percentile blood pressure values for pregnant women is helpful in identification of high-risk women of developing PIH or PE. The risk of PIH or PE in pregnant women with blood pressure ≥P₉₅ but <140/90 mmHg has significantly increased compared with women with blood pressure <P₉₅.

New types of ATP-grasp ligase are associated with the novel pathway for complicated mycosporine-like amino acid production in desiccation-tolerant cyanobacteria

Mycosporine-like amino acids (MAAs) were widespread in diverse organisms to attenuate UV radiation. We recently characterized the large, complicated MAA mycosporine-2-(4-deoxygadusolyl-ornithine) in desert cyanobacterium Nostoc flagelliforme. Synthesis of this MAA requires the five-gene cluster mysABDC2C3. Here, bioinformatic analysis indicated that mysC duplication within five-gene mys clusters is strictly limited to drought-tolerant cyanobacteria. Phylogenic analysis distinguished these duplicated MysCs into two clades that separated from canonical MysCs. Heterologous expression of N. flagelliforme mys genes in Escherichia coli showed that MysAB produces 4-deoxygadusol. The ATP-grasp ligase of MysC3 catalyses the linkage of the δ- or ε-amino group of ornithine/lysine to 4-deoxygadusol, yielding mycosporine-ornithine or mycosporine-lysine respectively. The ATP-grasp ligase of MysC2 strictly condenses the α-amino group of mycosporine-ornithine to another 4-deoxygadusol. MysD (D-Ala-D-Ala ligase) functions following MysC2 to catalyse the formation of mycosporine-2-(4-deoxygadusolyl-ornithine). High arginine content likely provides a greater pool of ornithine over other amino acids during rehydration of desiccated N. flagelliforme. Duplication of ATP-grasp ligases is specific for the use of substrates that have two amino groups (such as ornithine) for the production of complicated MAAs with multiple chromophores. This five-enzyme biosynthesis pathway for complicated MAAs is a novel adaptation of cyanobacteria for UV tolerance in drought environments.

Elevated plasma β-hydroxybutyrate predicts adverse outcomes and disease progression in patients with arrhythmogenic cardiomyopathy

Sudden death could be the first symptom of patients with arrhythmogenic cardiomyopathy (AC), a disease for which clinical indicators predicting adverse progression remain lacking. Recent findings suggest that metabolic dysregulation is present in AC. We performed this study to identify metabolic indicators that predicted major adverse cardiac events (MACEs) in patients with AC and their relatives. Comparing explanted hearts from patients with AC and healthy donors, we identified deregulated metabolic pathways using quantitative proteomics. Right ventricles (RVs) from patients with AC displayed elevated ketone metabolic enzymes, OXCT1 and HMGCS2, suggesting higher ketone metabolism in AC RVs. Analysis of matched coronary artery and sinus plasma suggested potential ketone body synthesis at early-stage AC, which was validated using patient-derived induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) in vitro. Targeted metabolomics analysis in RVs from end-stage AC revealed a "burned-out" state, with predominant medium-chain fatty acid rather than ketone body utilization. In an independent validation cohort, 65 probands with mostly non-heart failure manifestations of AC had higher plasma β-hydroxybutyrate (β-OHB) than 62 healthy volunteers (P < 0.001). Probands with AC with MACE had higher β-OHB than those without MACE (P < 0.001). Among 94 relatives of probands, higher plasma β-OHB distinguished 25 relatives having suspected AC from nonaffected relatives. This study demonstrates that elevated plasma β-OHB predicts MACE in probands and disease progression in patients with AC and their clinically asymptomatic relatives.

[Analysis of pregnancy outcome after fertility-preserving treatment among women with atypical endometrial hyperplasia or endometrial carcinoma]

Objective: To analyze the pregnancy outcome, influencing factors and recurrence of fertility-preserving therapy for women with atypical endometrial hyperplasia (AEH) or endometrial carcinoma (EC). Methods: The multi-center retrospective study included 107 women with AEH or EC for fertility-preserving therapy in 10 hospitals from January 1st, 2009 to December 31st, 2018. The clinical pregnancy rate, live birth rate and recurrence of 66 patients with urgent child-bearing requirements after fertility-preserving treatment were analyzed. Results: (1) Among the 66 AEH and EC women with urgent child bearing requirements, 24 women chose spontaneous pregnancy, the clinical pregnancy rate was 54.2% (13/24) and the live birth rate was 41.7% (10/24), the median time from fertility-preserving therapy withdrawal to clinical pregnancy was 5.5 months. Forty-two women chose assisted reproductive technology (ART), the clinical pregnancy rate was 59.5% (25/42) and the live birth rate was 35.7% (15/42), the median time from fertility-preserving therapy withdrawal to clinical pregnancy was 19.5 months. The time from fertility-preserving therapy withdrawal to pregnancy in women receiving ART was significantly longer than that in women with spontaneous pregnancy (P=0.048). (2) Age and intrauterine adhesions were independent factors affecting the clinical pregnancy rate (P<0.05). (3) Among 107 patients with AEH or EC, the recurrence rate was 27.1% (29/107). Among the 42 cases who chose ART, 9 of them recurred before ART treatment, who received the fertility-preserving therapy again and then ART treatment, 8 women got clinical pregnancy,5 of them delivered at least a live birth. Conclusions: Women with AEH or EC could achieved satisfactory clinical pregnancy rate and live birth rate after fertility-preserving therapy. Age and intrauterine adhesions are independent factors affecting clinical pregnancy rate. The women with recurrent AEH or EC could be treated with fertility-preserving therapy again and get a satisfactory pregnancy outcome.

[Analysis of the feasibility and prognostic value of circulating tumor DNA in detecting gene mutations in small cell lung cancer]

Objective: To investigate the feasibility of circulating tumor DNA (ctDNA) in detecting small cell lung cancer (SCLC) gene mutations and its prognostic value in chemotherapy and/or radiotherapy for SCLC patients. Methods: A total of 77 SCLC patients who were admitted to the Department of Thoracic Medical Oncology and the Department of Thoracic Radiation Oncology of Zhejiang Cancer Hospital from July 2016 to November 2019 were included. There were 66 males and 11 females, with a median age of 60 years. Among them, 42 cases were in limited stage (LS) and 35 cases were in extensive stage (ES). Next-generation sequencing (NGS) of patients' plasma ctDNA was performed before treatment. The differences of mutated genes and signaling pathways between LS and ES patients were analyzed and compared. Blood-based tumor mutation burden (bTMB) was calculated according to detected somatic cell mutations. Patients were divided into the high bTMB and the low bTMB groups according to the optimal threshold calculated by R software. Log-rank tests were used to compare progression-free survival (PFS) between the high bTMB and the low bTMB groups. Results: Among the 77 patients, 76 patients had gene mutations detected in their plasma, and the positive rate of ctDNA test was 98%. Among the 76 patients, the genes with the highest mutation frequency were TP53 (89%), RB1 (70%), LRP1B (34%), CREBBP (21%), MLL3 (21%), MLL2 (16%), NOTCH1 (13%), ROS1 (13%), BRCA2 (12%), and PTPRD (12%). The most common mutated genes in LS patients were TP53 (90%), RB1 (68%), LRP1B (24%), MLL2 (22%), and BRCA2 (17%); the most common mutated genes in ES patients were TP53 (89%), RB1 (71%), LRP1B (46%), CREBBP (31%), and MLL3 (29%). The mutation rates of NOTCH1 and CREBBP genes were significantly higher in ES patients (31.4% and 22.9%) than those in LS patients (11.9% and 4.8%) (both P<0.05). Signaling pathway analysis showed that there were more NOTCH pathway gene variations in ES patients. Among LS patients, patients in the high bTMB group (≥ 6.96 mutations/Mb) had a longer PFS than that in the low bTMB group (<6.96 mutations/Mb) (P=0.033); but no such difference was noted in ES patients. Conclusion: Plasma ctDNA sequencing detected SCLC gene mutation profiles similar to those reported in previous literature, thus ctDNA could be used as a tool to study SCLC genomics; the mutation spectra of ES-SCLC and LS-SCLC were different. bTMB has potential prognostic value in LS-SCLCs treated with chemoradiotherapy.

[Prospective cohort study of fetal nuchal translucency in first-trimester and pregnancy outcome]

Objective: To explore the relationship between fetal nuchal translucency (NT) in the first trimester and pregnancy outcome. Methods: A prospective cohort study was conducted in Nanjjing Drum Tower Hospital from December 2015 to December 2018, 4 958 singleton pregnant women were enrolled to screen fetal ultrasound structure and serology in the first trimester, ultrasound in the second trimester and neonatus physical examination 28 days after birth. According to the results of NT, 167 cases of fetus with increased NT (≥3.0 mm) and 4 791 cases of normal NT were divided, moreover, 86 cases with isolate increased NT and 81 cases of increased NT combined with structural abnormality. The prognosis of fetuses with different NT thickness was analyzed, and the pregnancy outcome of fetuses with isolate increased NT or combined with structural abnormality were analyzed. In the first trimester, if the fetal structure was abnormal or the serological screening result was high risk, the chromosomal microarray analysis (CMA) would be performed by chorionic villus sampling to determine the prenatal diagnosis. Results: (1) The pregnancy outcome for fetus of normal NT: there were 4 791 cases with normal NT. Totally, 4 726 cases with normal NT and no structural abnormalities were screened out in the firsttrimester. In this group, 5 cases of aneuploidies were diagnosed based on high risk of maternal serum biomarkers and 83 cases of structural abnormalities were screened out in the subsequent ultrasound scan and the neonatal examination. Another 65 cases with normal NT present complicated with structural anomalies were screened out in the first trimester and 4 cases were diagnosed as aneuploidies. (2) The pregnancy outcome for fetus of isolate increased NT: 66 (76.7%, 66/86) cases of isolated increased NT were performed CMA, 3 cases were diagnosed as trisomy 21 and terminated pregnancy. Another 4 cases were terminated pregnancy privately without cytogenetic diagnosis. No further anomalies were found in 79 cases till 6 to 21 months postnatally. (3) The pregnancy outcome for fetus of increased NT with structural anomalies: increased NT present with structural anomalies were screened out by detailed anomaly scan in the first trimester and 32 of them were confirmed as aneuploidies. In this group, 70 cases terminated pregnancy, 2 cases had spontaneous miscarriages and 9 cases had liveborns (1 newborn was found ventricular septal defect). (4) The pregnancy outcome for fetus of increased NT with or without structural anomalies: the percentage of aneuploidies in fetuses with isolated increased NT (3.5%, 3/86) was significantly lower than those with structural abnormalities (39.5%,32/81). The healthy survival rate in fetuses with isolated increased NT (91.9%,79/86) was significantly higher than those with structural abnormalities (9.9%, 8/81). Conclusions: A detailed first-trimester anomaly scan could improve prenatal screening efficiency of birth defects. Compared to the fetuses with increased NT combined with structural abnormalities, the healthy survival rate of fetuses with isolated increased NT based on detailed first-trimester anomaly scan is higher and the percentage of fetal aneuploidies is lower.

[Clinical efficacy and pregnancy outcomes of fertility-preserving re-treatment after recurrence of the patient with atypical endometrial hyperplasia and early stage endometrial carcinoma]

Objective: To analyze the clinical efficacy and pregnancy outcomes of fertility- preserving re-treatment in patients with recurrent atypical endometrial hyperplasia (AEH) and early stage endometrial carcinoma (EEC) after achieved complete remission (CR) of primary fertility-preserving therapy. Methods: There were 104 cases of AEH and EEC collected from 9 hospitals in the multi-center research network platform of fertility-preserving therapy of endometrial carcinoma in China from January 2005 to May 2019. Thirth-one cases of them relapsed from four hospitals mentioned above,who achieved CR after primary fertility-preserving therapy,was analyzed retrospectively. Of the 31 cases, 27 cases chose fertility-preserving re-treatment. The demographic characteristics, re-treatment effect, clinical factors and pregnancy outcomes were observed. Results: (1) There were 16 AEH cases and 11 ECC cases among 27 recurrent patients who chose fertility-preserving therapy again. After re-treatment, CR was found in 13 out of 16 cases of AEH and 9 out of 11 cases of EEC. The overall CR rate was 81% (22/27). (2) After CR of recurrence, 5 cases (23%, 5/22) of re-recurrence were found after with a median time of 33 months (range 21-80 months). There were 4 cases underwent comprehensive surgical staging, and 1 patient chose the third round of fertility preservation therapy with fully informed consent, and CR was reached after 15 months. (3) There were 16 cases with pregnancy intention, with a total of 12 pregnancies, including 5 cases were natural pregnancy and 7 cases were assisted reproductive technology pregnancy. There were 5 live births. The follow-up time was up to May 2019, and the median follow-up time was 73 months (range 0-123 months). All 27 patients had disease free survival. Conclusions: Recurrent patients with AEH and EEC after achieving successful fertility-preserving therapy could choose fertility-preserving therapy again with comprehensive assessment and fully informed consent. After re-treatment, there is a certain tumor CR rate and pregnancy rate, while the close follow-up is required during treatment.

Deficiency of Gpr1 improves steroid hormone abnormality in hyperandrogenized mice

BACKGROUND

Polycystic ovary syndrome (PCOS) is a complex genetic disease with multifarious phenotypes. Many researches use dehydroepiandrosterone (DHEA) to induce PCOS in pubertal mouse models. The aim of this study was to investigate the role of GPR1 in dehydroepiandrosterone (DHEA)-induced hyperandrogenized mice.

METHODS

Prepubertal C57BL/6 mice (25 days of age) and Gpr1-deficient mice were each divided into two groups and injected daily with sesame oil with or without DHEA (6 mg/100 g) for 21 consecutive days. Hematoxylin and eosin (H&E) staining was performed to determine the characteristics of the DHEA-treated ovaries. Real-time PCR was used to examine steroid synthesis enzymes gene expression. Granulosa cell was cultured to explore the mechanism of DHEA-induced, GPR1-mediated estradiol secretion.

RESULTS

DHEA treatment induced some aspects of PCOS in wild-type mice, such as increased body weight, elevated serum testosterone, increased number of small, cystic, atretic follicles, and absence of corpus luteum in ovaries. However, Gpr1 deficiency significantly attenuated the DHEA-induced weight gain and ovarian phenotype, improving steroidogenesis in ovaries and estradiol synthesis in cultured granulosa cells, partially through mTOR signaling.

CONCLUSIONS

In conclusion, Gpr1 deficiency leads to the improvement of steroid synthesis in mice hyperandrogenized with DHEA, indicating that GPR1 may be a therapeutic target for DHEA-induced hyperandrogenism.

Sensing and Transmitting Intracellular Amino Acid Signals through Reversible Lysine Aminoacylations

Amino acids are known regulators of cellular signaling and physiology, but how they are sensed intracellularly is not fully understood. Herein, we report that each aminoacyl-tRNA synthetase (ARS) senses its cognate amino acid sufficiency through catalyzing the formation of lysine aminoacylation (K-AA) on its specific substrate proteins. At physiologic levels, amino acids promote ARSs bound to their substrates and form K-AAs on the ɛ-amine of lysines in their substrates by producing reactive aminoacyl adenylates. The K-AA marks can be removed by deacetylases, such as SIRT1 and SIRT3, employing the same mechanism as that involved in deacetylation. These dynamically regulated K-AAs transduce signals of their respective amino acids. Reversible leucylation on ras-related GTP-binding protein A/B regulates activity of the mammalian target of rapamycin complex 1. Glutaminylation on apoptosis signal-regulating kinase 1 suppresses apoptosis. We discovered non-canonical functions of ARSs and revealed systematic and functional amino acid sensing and signal transduction networks.

An alternative cetyltrimethylammonium bromide-based protocol for RNA isolation from blackberry (Rubus L.)

Isolation of high-quality RNA free of contaminants, such as polyphenols, proteins, plant secondary metabolites, and genomic DNA from plant tissues, is usually a challenging but crucial step for molecular analysis. We developed a novel protocol based on the cetyltrimethylammonium bromide method to isolate high-quality RNA from blackberry plant tissues, especially fruits. Most DNA was removed when acetic acid was utilized, before RNA precipitation. Thus, lithium chloride, a reagent widely used for RNA purification, was not needed. The isolation time was shortened to less than 3 h. The RNA was quite pure, with little DNA contamination. The quality of the RNA was assessed by spectrophotometric readings and electrophoresis on agarose gels. It was good enough for downstream enzymatic reactions, such as reverse transcription-PCR, cloning and real-time PCR assay. The method yielded an amount of total RNA comparable to previously described protocols.

Metabolic alterations in the hamster co-infected with Schistosoma japonicum and Necator americanus

Co-infection with hookworm and schistosomes is a common phenomenon in sub-Saharan Africa, as well as in parts of South America and southeast Asia. As a first step towards understanding the metabolic response of a hookworm-schistosome co-infection in humans, we investigated the metabolic consequences of co-infection in an animal model, using a nuclear magnetic resonance (NMR)-based metabolic profiling technique, combined with multivariate statistical analysis. Urine and serum samples were obtained from hamsters experimentally infected with 250 Necator americanus infective L(3) and 100 Schistosoma japonicum cercariae simultaneously. In the co-infection model, similar worm burdens were observed as reported for single infection models, whereas metabolic profiles of co-infection represented a combination of the altered metabolite profiles induced by single infections with these two parasites. Consistent differences in metabolic profiles between the co-infected and non-infected control hamsters were observed from 4 weeks p.i. onwards. The predominant metabolic alterations in co-infected hamsters consisted of depletion of amino acids, tricarboxylic acid cycle intermediates (e.g. citrate and succinate) and glucose. Moreover, alterations of a series of gut microbial-related metabolites, such as decreased levels of hippurate, 3-hydroxyphenylpropionic acid, 4-hydroxyphenylpropionic acid and trimethylamine-N-oxide, and increased concentrations of 4-cresol glucuronide and phenylacetylglycine were associated with co-infection. Our results provide a first step towards understanding the metabolic response of an animal host to multiple parasitic infections.

Structure-activity relationships in the hydrophobic interactions of polyphenols with cellulose and collagen

Polyphenol interactions with both cellulose and collagen in the solid state have been studied by using chromatography on cellulose and by evaluating the hydrothermal stability of the polyphenol treated sheepskin collagen. Twenty-four polyphenolic compounds were studied, including seven glucose-based gallotannins, five polyalcohol-based gallotannins, and twelve ellagitannins. In the cellulose-polyphenols systems, the polyphenol's affinity to cellulose is positively correlated with their molecular masses, the number of galloyl groups, and their hydrophobicity (logP). The polyphenol treatment increased the hydrothermal stability of collagen samples, and such effects are also positively correlated with the molecular masses, total number of galloyl groups and the hydrophobicity of polyphenols. Ellagitannins showed much weaker interactions with both biopolymers than gallotannins having similar molecular mass, the same number of galloyl groups, and the same number of phenolic hydroxyl groups. It is concluded that, for the polyphenol interactions with both cellulose and collagen, (1) the galloyl group of polyphenols is the functional group; (2) the strength of interactions are positively correlated with molecular size, the number of galloyl groups and the hydrophobicity of polyphenols; (3) the hydrophobic interactions are of great significance; and (4) the interactions are strongly dependent on the flexibility of galloyl groups.

Use of DSC to detect the heterogeneity of hydrothermal stability in the polyphenol-treated collagen matrix

The hydrothermal stability of the collagen matrixes treated with plant polyphenols (tannins) depends on not only the strength of the polyphenol-collagen interactions but also the distribution uniformity of polyphenolic molecules within the collagen fibrils. Traditional methods of uniformity tests rely heavily on the expertise of workers and are thus subjective. This paper describes a differential scanning calorimetry (DSC) study of the sheepskin collagen samples treated with hydrolyzable tannins, including two commercial tannins' extracts (chestnut and valonea), two pure ellagitannins (vescalagin and castalagin), and six synthetic gallotannins (di-galloyl-ethylene glycol (DGE), tri-galloyl-glycerol, tetra-galloyl-meso-erythritol, penta-galloyl-adonitol, penta-galloyl-glucose, and hexa-galloyl-ducitol). The collagen sample without polyphenol treatment and the sample treated with DGE showed a single sharp peak in their DSC thermogram with a full peak width at half height (fwhh) of 3-4 degrees C. The samples treated with other tannins all showed multiple peak DSC profiles with the fwhh of each peak at about 3-4 degrees C. These multiple peak profiles imply that in these polyphenol-treated samples, there is a distribution of collagen molecules having different hydrothermal stability. The results have demonstrated that DSC offers an objective method to detect the stability heterogeneity of collagen matrixes in the solid state, providing a useful tool for the leather industry to evaluate the uniformity of leather tanning.

Molecular dynamics of polycrystalline cellobiose studied by solid-state NMR

Molecular motions of polycrystalline cellobiose have been investigated by measuring proton spin-lattice relaxation times, T1 and T1rho, and the second moment, M2, in both protonated and D2O exchanged forms over the temperature range 120-380 K. T1 relaxation is dominated by the motions of hydroxyl groups between 150 and 380 K, characterised by an activation energy of about 8.74 kJ/mol, whereas T1rho relaxation is driven by the motions of the same groups between 120 and 300 K. T1rho results suggest that hydroxyl groups have a distribution of dynamics. Motion of methylene groups was detected in the second-moment experiments at about 350 K, characterised by activation energy of about 40 kJ/mol. Consideration of the calculated and observed rigid-lattice second moments suggests that the reported X-ray data are incorrect for the inter-proton distance on C6'. 13C CPMAS spectra of both protonated and deuterated cellobiose have also been measured. Spectra of the deuterated material showed the existence of a second crystalline form in addition to the normal form.

Correlation of tumor and whole-body dosimetry with tumor response and toxicity in refractory neuroblastoma treated with (131)I-MIBG

The purpose of our study was to determine the effect of tumor-targeted radiation in neuroblastoma by correlating administered (131)I-metaiodobenzylguanidine (MIBG) activity to tumor and whole-body dosimetry, tumor volume change, overall response, and hematologic toxicity.

METHODS

Eligible patients had MIBG-positive lesions and tumor-free, cryopreserved hematopoietic stem cells. Activity was administered according to body weight and protocol as part of a phase I and phase II study. The whole-body radiation dose was derived from daily 1-m exposure measurements, the tumor self-absorbed radiation dose (TSARD) was determined from scintillation-camera conjugate views, and the tumor volume was measured using CT or MRI.

RESULTS

Forty-two patients with refractory neuroblastoma (16 with prior hematopoietic stem cell transplant) received a median activity of 555 MBq/kg (15 mCi/kg) (range, 93-770 MBq/kg) and a median total activity of 11,470 MBq (310 mCi) (range, 3,330-30,969 MBq). The median whole-body radiation dose was 228 cGy (range, 57-650 cGy) and the median TSARD was 3,300 cGy (range, 312-30,500 cGy). Responses among evaluable patients included 16 partial response, 3 mixed response, 14 stable disease, and 9 progressive disease. Higher TSARD values predicted better overall disease response (P < 0.01). The median decrease in tumor volume was 19%; 18 tumors decreased, 4 remained stable, and 5 increased in size. Correlation was seen between administered activity per kilogram and whole-body dose as well as hematologic toxicity (assessed by blood platelet and neutrophil count nadir) (P < 0.05). The median whole-body dose was higher in the 11 patients who required hematopoietic stem cell infusion for prolonged neutropenia versus the 31 patients who did not (323 vs. 217 cGy; P = 0.03).

CONCLUSION

Despite inaccuracies inherent in dosimetry methods, (131)I-MIBG activity per kilogram correlated with whole-body radiation dose and hematologic toxicity. The TSARD by conjugate planar imaging predicted tumor volume decrease and also correlated with overall tumor response.

Absolute quantification of regional myocardial uptake of 99mTc-sestamibi with SPECT: experimental validation in a porcine model

We have evaluated a method for absolute in vivo quantification of 99mTc-sestamibi uptake in a porcine model of myocardial perfusion.

METHODS

Correlated CT and radionuclide images were obtained from eight adult pigs using a combined CT-SPECT imaging system. In each case, the CT image is used to generate an object-specific attenuation map that is incorporated into an iterative algorithm for reconstruction and attenuation correction of the radionuclide image. Anatomic information available from the correlated CT image is used to correct the radionuclide image for partial-volume errors by mathematically modeling the radionuclide imaging process. A volume of interest, or template, that approximates the geometric extent of the myocardium is defined from the CT image. Once defined, the template is assigned unit activity and is mathematically projected using a realistic physical model of the radionuclide imaging process including nonideal collimation and object-specific attenuation. The template is then reconstructed from these projections to obtain a pixel-by-pixel partial-volume correction for the myocardium in the radionuclide image. The CT image is also used to delimit the anatomic boundaries of the myocardium for quantification of the radionuclide images. The pixel intensities in the corrected radionuclide image are calibrated in units of activity concentration (MBq/g) and compared with the ex vivo activity concentration measured directly from the excised myocardium.

RESULTS

Without corrections, the measured in vivo activity concentration in the porcine myocardium was only 10% of the true value. Correcting for object-specific attenuation improved the accuracy of this measurement but resulted in values that were still only 42% of the true value. By correcting for both attenuation and partial-volume errors, we were able to achieve absolute quantification with an accuracy error near 10%.

CONCLUSION

We have shown that, by applying object-specific attenuation corrections and suitable partial-volume corrections, absolute regional activity concentration can be measured accurately in the porcine myocardium.

NMR diffusometry of oil-in-water emulsions

The diffusion propagator of the continuous aqueous phase of concentrated oil-in-water emulsions is used to probe the relationship between emulsion microstructure and bulk rheological properties. This is done by expanding the stimulated echo amplitude, S(q,Delta), as a multiple exponential time series expansion in Delta, with wavevector dependent expansion coefficients. These coefficients are compared with predictions from several theoretical models for three types of stable emulsion, each differing in microstructure. Empiric relationships between the wavevector expansion coefficients and bulk rheology are established.

Solid state NMR and X-ray diffraction studies of alpha-D-galacturonic acid monohydrate

Crystalline alpha-D-galacturonic acid monohydrate has been studied by 13C CPMAS NMR and X-ray crystallography. The molecular dynamics were investigated by evaluating 13C spin-lattice relaxation in the rotating frame (T1rho) and chemical-shift-anisotropy properties of each carbon. Only limited molecular motions can be detected in the low frequency (< 10(4) Hz) range by 13C relaxation time measurements (T1rho) and changes of chemical shift anisotropy properties as a function of temperature. X-ray analysis (at both ambient temperature and 150 K) shows that the acid has the usual chair-shaped, pyranose ring conformation, and that the acid and water molecules are linked, through all their O-H groups, in an extensively hydrogen-bonded lattice.

Neuroblastoma imaging using a combined CT scanner-scintillation camera and 131I-MIBG

High-dose administration of 131I-metaiodobenzylguanidine (131I-MIBG) continues to be a promising treatment for neuroblastoma. However, currently used methods of estimating 131I-MIBG uptake in vivo may be too inaccurate to properly monitor patient radiation exposure doses. To improve localization and uptake measurements over currently practiced techniques, we evaluated different methodologies that take advantage of the correlated patient data available from a combined CT-scintillation camera imaging system.

METHODS

Serial CT and radionuclide scans of three patients were obtained on a combined imaging system. SPECT images were reconstructed using both filtered backprojection and maximum-likelihood expectation maximization (MLEM). Volumes of interest (VOIs) were defined on anatomic images and automatically correlated to spatial volumes in reconstructed SPECT images. Several radionuclide quantification methods were then compared. First, the mean reconstructed values within coregistered SPECT VOIs were estimated from MLEM reconstructed images. Next, we assumed that reconstructed activity in SPECT voxels were linear combinations of activities present in individual objects, weighted by geometric factors derived from CT images. After calculating the weight factors by modeling the SPECT imaging process with anatomically defined VOIs, least-squares fitting was used to estimate the activities within lesion volumes. We also estimated the lesion activities directly from planar radionuclide images of the patients using similar linearity assumptions. Finally, for comparison, lesion activities were estimated using a standard conjugate view method.

RESULTS

Activities were quantified from three patients having a total of six lesions with volumes ranging from 0.67 to 117 mL. Methods that used CT data to quantify lesion activities gave similar results for planar and tomographic radionuclide data. Estimating activity directly from mean VOI values in MLEM-reconstructed images alone consistently provided estimates lower than CT-aided methods because of the limited spatial resolution of SPECT. Values obtained with conjugate views produced differences up to fivefold in comparison with CT-aided methods.

CONCLUSION

These results show that anatomic information available from coregistered CT images may improve in vivo localization and measurement of 131I-MIBG uptake in tumors.

Green tea polyphenols react with 1,1-diphenyl-2-picrylhydrazyl free radicals in the bilayer of liposomes: direct evidence from electron spin resonance studies

Free radical scavenging reactions of green tea polyphenols (GTP) were investigated with electron spin resonance (ESR) spectroscopy in the phospholipid bilayer of liposomes, using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical as a model. The results showed that (1) GTP reacts with DPPH radicals in the bilayer of liposomes of both 1-hexadecanoyl-2-[(cis,cis,cis,cis,cis,cis)-4,7,10, 13,16,19-docosahexaenoyl]-sn-glycero-3-phosphocholine (DHAPC) and 1, 2-di[cis-9-hexadecenoyl]-sn-glycero-3-phosphocholine) (DPPC); and (2) GTP protects DHAPC liposomes effectively from the oxidation initiated by DPPH radicals. These results provide direct evidence that GTP reacts with free radicals in the model membrane and support the hypothesis that GTP protects unsaturated phospholipids from oxidation by reacting directly with the radicals.

Intrinsic dual-energy processing of myocardial perfusion images

We have developed a software-based method for processing dual-energy 201TI SPECT emission projection data with the goal of calculating a spatially dependent index of the local impact of gamma-ray attenuation. We refer to this method as intrinsic dual-energy processing (IDEP).

METHODS

IDEP exploits the differential attenuation of lower energy emissions (69-83 keV) and higher energy emissions (167 keV) resulting from the decay of 201TI to characterize the relative degree of low-energy gamma-ray attenuation throughout the myocardium. In particular, IDEP can be used to estimate the relative probability that a low-energy gamma-ray emitted from a particular region of the myocardium is detected during the acquisition of SPECT projection data. Studies on phantoms and healthy human volunteers were performed to determine whether the IDEP method yielded detection probability images with systematic structure visible above the noise of these images and whether the systematic structure in the detection probability images could be rationalized physically. In patient studies, the relative regional detection probabilities were applied qualitatively to determine the likely effects of attenuation on the distribution of mapped photon emissions.

RESULTS

Measurements of the detection probability in uniform phantoms showed excellent agreement with those obtained from computer simulations for both 180 degrees and 360 degrees acquisitions. Additional simulations with digital phantoms showed good correlation between IDEP-estimated detection probabilities and calculated detection probabilities. In patient studies, the IDEP-derived detection probability maps showed qualitative agreement with known nonuniform attenuation characteristics of the human thorax. When IDEP data were integrated with the findings on the emission scan, the correlation with coronary anatomy (known in 6 patients and hypothesized on the basis of clinical and electrocardiographic parameters in 5 patients) was improved compared with evaluating the mapped emission image alone.

CONCLUSION

The IDEP method has the potential to characterize the attenuation properties of an object without use of a separate transmission scan. Coupled with the emission data, it may aid coronary diagnosis.

13C CPMAS studies of plant cell wall materials and model systems using proton relaxation-induced spectral editing techniques

The solid state 13C CPMAS NMR spectra of plant cell walls are often complex owing to superposition of resonances from different polysaccharides and the heterogeneity of the cell wall assembly. In this paper, we describe the application of a set of proton relaxation-induced spectral editing (PRISE) experiments which combine 1H relaxation properties (T1, T1rho, T2) with 13C high resolution spectroscopy (CPMAS) to relate the dynamics of the plant cell walls and model systems to their domain structural details. With PRISE it has been found that in plant cell wall materials, cellulose is always associated with the long components of spin-lattice relaxation in both the laboratory and rotating frames whereas non-cellulose polysaccharides (pectin and hemicellulose) are associated with the short ones. For the proton T2 relaxation, cellulose is only associated with the short component (below 20 micros), pectin contributes to both the short component and the long one.

Proton NMR relaxation studies of solid tyrosine derivatives and their mixtures with L-leucinamide

Proton NMR relaxation time measurements were carried out on solid tyrosine derivatives: acetyl-L-tyrosine ethyl ester (Ac-Tyroet), N-carbobenzyloxy-L-tyrosine ethyl ester (CBZ-Tyroet), N-trifluoroacetyl-L-tyrosine ethyl ester (TFAc-Tyroet) and their mixtures with L-leucinamide. It was found that spin-lattice relaxation was driven mainly by methyl group rotation it low temperature for the pure solids and the mixtures. Benzene ring flipping motion and a third motion (possibly whole molecule tumbling) were found to be responsible for relaxing Ac-Tyroet and CBZ-Tyroet at high temperature. However, these motions were highly hindered in TFAc-Tyroet. Molecular tumbling motion was detected in the supercooled liquid mixtures of L-leuNH/CBZ-Tyroet and L-leuNH/Ac-Tyroet, while this motion is absent in the mixture L-leuNH/TFAc-Tyroet. The hindered motion in TFAc-Tyroet may be one of the factors affecting its ability to form a supercooled liquid with L-leucinamide.

Molecular motions of D-alpha-galacturonic acid (GA) and methyl-D-alpha-galacturonic acid methyl ester (MGAM) in the solid state-A proton NMR study

The molecular motions of D-alpha-galacturonic acid monohydrate (GA) and its derivative methyl-alpha-D-galacturonic acid methyl ester monohydrate (MGAM) in the solid state have been studied using 1H NMR. Both protonated and deuterium exchanged samples have been used. Spin-lattice relaxation times in the laboratory and rotating frames as well as second moments have been measured over the temperature range 90-370 K. Analysis of results has shown that in GA spin-lattice relaxation is chiefly by hydroxyl groups and water of crystallization. In MGAM, methyl groups dominate spin-lattice relaxation in the laboratory frame at the low temperature. Hydroxyl groups and water of crystallization contribute to the spin-lattice relaxation in the laboratory frame in the high temperature region. In the rotating frame motion of hydroxyl groups and water of crystallization provide the main relaxation pathway. Changes in the static second moment with temperature can be reasonably well predicted using values of correlation time and motionally averaged second moments obtained by fitting the spin-lattice relaxation data. 13C CPMAS spectra for GA and MGAM are also described.

A bound on the energy resolution required for quantitative SPECT

Scattered radiation is one of several physical perturbations that limit the accuracy of quantitative measurements in single-photon emission computed tomography (SPECT). Improvement in detector energy resolution leads to a reduction of scatter counts and a corresponding improvement in the quantitative accuracy of the SPECT measurement. In this study, simulated SPECT projections of a simple myocardial perfusion phantom were used to investigate the effect of detector energy resolution on the data. The phantom consists of a spherical shell of radionuclide within a 15 cm radius water-filled cylinder. Each projection contains on the order of 3 x 10(5) counts. The results demonstrate that a full-width, half-maximum energy resolution of 3-4 keV is sufficient to render the error due to scatter insignificant compared to the uncertainty due to photon statistics in this case. Further simulations verify that because smaller objects produce less scatter, they can be imaged accurately with degraded energy resolution. These results are useful when designing prototype systems that utilize solid-state detectors and low-noise electronics to achieve improved energy resolution.

Study on the composition and structure of commercial chestnut tanning agent

Current research has focused on the composition of commercially used chestnut tannin extracts so as to provide a quantitative basis for studies of reactions, structure-property relationships, and applications of chestnut tannin extract. Two chestnut tannins, vescalagin and castalagin, have been isolated using chromatography on Sephadex LH-20 and cellulose. The structures of these compounds have been established by means of nuclear magnetic resonance and fast atom bombardment mass spectroscopy. Some other components have been found and analyzed by chromatography and spectroscopy, but their structures have not as yet been completely defined. These structural features, together with quantitative results for each component, provide a better understanding of the mode of action of complex commercial chestnut tannin extracts.