Multiparameter spectral CT-based radiomics in predicting the expression of programmed death ligand 1 in non-small-cell lung cancer

AIM

To explore the value of radiomics for predicting the expression of programmed death ligand 1 (PD-L1) in non-small-cell lung cancer (NSCLC) based on multiparameter spectral computed tomography (CT) images.

MATERIALS AND METHODS

A total of 220 patients with NSCLC were enrolled retrospectively and divided into the training (n=176) and testing (n=44) cohorts. The radiomics features were extracted from the conventional CT images, mono-energy 40 keV images, iodine density (ID) maps, Z-effective maps, and electron density maps. The logistic regression (LR) and support vector machine (SVM) algorithms were employed to build models based on radiomics signatures. The prediction abilities were qualified by the area under the curve (AUC) obtained from the receiver operating characteristic (ROC) curve. Internal validation was performed on the independent testing dataset.

RESULTS

The combined model for PD-L1 ≥1%, which consisted of the radiomics score (rad-score; p<0.0001), white blood cell (WBC; p=0.027) counts, and air bronchogram (p=0.003), reached the highest performance with the AUCs of 0.873 and 0.917 in the training and testing dataset, respectively, which was better than the radiomics model with the AUCs of 0.842 and 0.886. The combined model for PD-L1 ≥50%, which consisted of rad-score (p<0.0001) and WBC counts (p=0.027), achieved the highest performance in the training and testing dataset with AUCs of 0.932 and 0.903, respectively, which was better than the radiomics model with AUCs of 0.920 and 0.892, respectively.

CONCLUSION

The radiomics model based on the multiparameter images of spectral CT can predict the expression level of PD-L1 in NSCLC. The combined model can obtain higher prediction efficiency and serves as a promising method for immunotherapy selection.

Study on transient photocurrent induced by energy level defect of schottky diode irradiated by high power pulsed laser

The transient photocurrent is one of the key parameters of the spatial radiation effect of photoelectric devices, and the energy level defect affects the transient photocurrent. In this paper, by studying the deep level transient spectrum of a self-designed Schottky diode, the defect properties of the interface region of the anode metal AlCu and Si caused by high-temperature annealing at 150 ℃, 200 ℃ and 300 ℃ for 1200 h have been quantitatively analyzed. The study shows that the defect is located at the position of + 0.41 eV on the valence band, the concentration is 2.8 [Formula: see text] 1013/cm2, and the capture cross section is [Formula: see text] = 8.5 [Formula: see text] 1017. The impurity energy level mainly comes from the diffusion of Al atom in anode metal. We found that the defect did not cause the electrical performance degradation and obvious morphology change of the device, but the transient photocurrent increased significantly. The reason is that the high temperature treatment results in a growth in the density of states at the interface between AlCu-Si. The more mismatched dislocations and recombination center increased the reverse current of the heterojunction. The above view is proved by the TCAD simulation test.

Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.

Precision Measurement of Reactor Antineutrino Oscillation at Kilometer-Scale Baselines by Daya Bay

We present a new determination of the smallest neutrino mixing angle θ_{13} and the mass-squared difference Δm_{32}^{2} using a final sample of 5.55×10^{6} inverse beta-decay (IBD) candidates with the final-state neutron captured on gadolinium. This sample is selected from the complete dataset obtained by the Daya Bay reactor neutrino experiment in 3158 days of operation. Compared to the previous Daya Bay results, selection of IBD candidates has been optimized, energy calibration refined, and treatment of backgrounds further improved. The resulting oscillation parameters are sin^{2}2θ_{13}=0.0851±0.0024, Δm_{32}^{2}=(2.466±0.060)×10^{-3}  eV^{2} for the normal mass ordering or Δm_{32}^{2}=-(2.571±0.060)×10^{-3}  eV^{2} for the inverted mass ordering.

First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12 MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10 MeV is rejected with a significance of 6.2 standard deviations. A 29% antineutrino flux deficit in the prompt energy region of 8-11 MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-Q_{β} isotopes in commercial reactors.

Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT

A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.

[Comparison of the clinicopathological features between adenoid basal cell carcinoma and adenoid cystic carcinoma of the cervix]

Objective: To compare the clinical and histopathological characteristics of cervical adenoid basal cell carcinoma and adenoid cystic carcinoma for improving the diagnosis accuracy and differential diagnosis of these tumors. Methods: A retrospective study was conducted on 9 cases of cervical adenoid basal cell carcinoma and 3 cases of adenoid cystic carcinoma which were diagnosed and consulted at the First Medical Center of PLA General Hospital from March 2009 to April 2019. Detailed clinical data were reviewed. All pathological sections and immunohistochemical results were reviewed and the clinicopathological characteristics were analyzed. Follow-up information by telephone was collected and relevant literature was consulted. Results: Both tumors were more commonly found in postmenopausal women (the age of onset ranged 43-74 years). Adenoid basal cell carcinoma was often clinical asymptomatic. Most of them presented as abnormal smears of the cervix during physical examination, and there was no definite mass in colposcopy.Adenoid cystic carcinoma was mostly presented with abnormal vaginal bleeding. A mass was seen in colposcopy.Histologically, the two tumors were characterized by nest-like growth of the tumors, consisting of basal-like tumor cells, and often surrounded by palisade structures. The two lesions might coexist, or be mixed with squamous cell carcinoma or high-grade squamous intraepithelial lesions. The difference was that adenoid basal cell carcinoma was mostly located at the junction of cervical squamous epithelium and columnar epithelium and beneath the overlying epithelium, the tumor cells were arranged in nests, with squamous differentiation in the center of the nests, or in double-layer adenoid arrangement. The cell morphology was bland with occasional mitoses, and the stromal reaction was not obvious. And adenoid cystic carcinoma cells in the nest arranged like a sieve, the homogenous red-stained and blue-stained secretions were observed in the sieve holes, with obvious cell atypia, frequent mitoses, and obvious stromal reaction.In one case of adenoid cystic carcinoma, sarcomatoid area presented around the nests.Both of them were positive in clinical HPV test. Among the 9 cases of adenoid basal cell carcinoma, 3 were tested for HPV and 5 were tested for p16, and all showed positive expression. Among the 3 cases of adenoid cystic carcinoma, 2 were tested for HPV and 3 were tested for p16, both of which showed positive expression. Telephone follow-up was conducted by June 2019(follow-up time ranged 2-37 months). No recurrence or metastasis occurred in 7 of the 9 cases of adenoid basal cell carcinoma, while 1 case had a ground-glass nodule in lung and another had recurrence of vaginal stump 32 months after the surgery.One case of adenoid cystic carcinoma developed lung metastasis 8 months after surgery and died 2 years after surgery; another case was followed up for 6 months, which showed no recurrence or metastasis; the third case was lost to follow-up. Conclusions: Both adenoid cystic carcinoma and adenoid basal cell carcinoma of the cervix are the tumors originating from cervical reserve cells and are associated with high-risk HPV infection. Due to the differences in clinical treatment and prognosis, careful histological evaluation and immunohistochemical analysis should be carried out to make accurate pathological diagnosis.

Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments

Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θ_{μe} mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm_{41}^{2}, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL_{s} for Δm_{41}^{2}<13  eV^{2}. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CL_{s} for Δm_{41}^{2}<1.6 eV^{2}.

[Effects of parental rearing patterns and their consistency on the emotional and behavioral problems of preschool children]

Objective: To explore the effect of parental rearing patterns and their consistency on the emotional and behavioral problems of preschool children. Methods: From October to November 2017, 27 987 children aged 3 to 6 years old from 109 kindergartens in 11 cities of Hubei, Anhui and Jiangsu Provinces were selected by using the cluster sampling method. A total of 27 200 valid questionnaires which were completed by subjects' parents were collected. The emotional and behavioral problems of preschool children were collected by "strengths and difficulties questionnaire" and the parental rearing patterns were evaluated by the "Parental Behavior Scale". The differences in emotional and behavioral abnormality rates of preschool children with different characteristics were analyzed; with emotional and behavioral problems as dependent variables and parental support/participation and compulsion/hostility as independent variables, the multivariate logistic regression model was used to analyze the effect of parental rearing patterns and their consistency on the emotional and behavioral problems of preschool children. Results: The age of children was (4.35±0.96) years old, and 51.4% of children were 13 975 males. There were 24 634 (90.6%) urban children and 17 916 (65.9%) only children. Both parents with strong support/participation accounted for 14.9%, and those with poor support/participation accounted for 11.9%; both parents with strong compulsion/hostility accounted for 15.2%, and those with low compulsion/hostility accounted for 11.3%. The rates of emotional symptoms, conduct behavior, hyperactive behavior, peer interaction, total difficulty score, and abnormal prosocial behavior of preschool children were 9.5%, 9.5%, 18.2%, 24.5%, 11.2%, and 10.2%, respectively. The multivariate logistic regression model analysis showed that after adjusting for gender, only child, living area, family economic status, mother's age and education level, father's education level, and other factors, compared with fathers/mothers with strong support/participation and low compulsion/hostility and parents with strong support/participation and low compulsion/hostility, preschool children who had fathers/mothers with poor support/participation and strong compulsion/hostility or parents with poor support/participation and strong compulsion/hostility were more likely to have emotional symptoms, conduct behavior, hyperactive behavior, peer interaction, total difficulty score, and abnormal prosocial behavior (P<0.05). Conclusions: Parental rearing patterns and their consistency are related to the emotional and behavioral problems of preschool children.

Extraction of the ^{235}U and ^{239}Pu Antineutrino Spectra at Daya Bay

This Letter reports the first extraction of individual antineutrino spectra from ^{235}U and ^{239}Pu fission and an improved measurement of the prompt energy spectrum of reactor antineutrinos at Daya Bay. The analysis uses 3.5×10^{6} inverse beta-decay candidates in four near antineutrino detectors in 1958 days. The individual antineutrino spectra of the two dominant isotopes, ^{235}U and ^{239}Pu, are extracted using the evolution of the prompt spectrum as a function of the isotope fission fractions. In the energy window of 4-6 MeV, a 7% (9%) excess of events is observed for the ^{235}U (^{239}Pu) spectrum compared with the normalized Huber-Mueller model prediction. The significance of discrepancy is 4.0σ for ^{235}U spectral shape compared with the Huber-Mueller model prediction. The shape of the measured inverse beta-decay prompt energy spectrum disagrees with the prediction of the Huber-Mueller model at 5.3σ. In the energy range of 4-6 MeV, a maximal local discrepancy of 6.3σ is observed.

[Analysis of Transport and Transformation Characteristics Between Dissolved Phosphorus and Particulate Phosphorus in Water of the Three Gorges Reservoir]

To understand the difference between transport coefficients of water runoff, sand discharge, and phosphorus flux in each subsection of a river, a judgement method for analyzing the characteristics of phosphorus transport and transformation in water of rivers was established in this study. Based on the measured data of water runoff, sand discharge, and phosphorus fraction concentrations in the water of the Three Gorges Reservoir (TGR) in January and July 2015, characteristics of phosphorus transport and transformation in the water were analyzed by using the conceptual method. The results showed that the predominant phosphorus fraction in water of the TGR was total dissolved phosphorus (TDP), which accounted for 51%-96% of total phosphorus in water. The TDP flux relative to runoff in the TGR decreased in January 2015 That was caused by the adsorption of TDP by suspended particles in the dry season. In contrast, TDP flux showed additive effect relative to water runoff in July 2015 due to exogenous water inputs with high TDP concentrations in the wet season. Both sand and total particulate phosphorus (TPP) presence in the water showed obvious sediment and retention characteristics during the two periods. The TPP flux presented an additive effect relative to sand discharge, meaning that the major transformation direction of phosphorus fractions was from TDP to TPP. The subsection between Qingxichang and Wanzhou was the main retention area of water, sand, and phosphorus in the TGR, which can be associated with the enhancement of phosphorus adsorption capacity caused by particle size reduction of suspended particles in the subsection.

[Clinicopathological analysis of cervical basaloid squamous cell carcinoma]

Objective: To investigate the clinical and histopathological features of cervical basal squamous cell carcinoma (BSCC). Methods: A retrospective analysis of 10 cases of cervical BSCC was carried out. The clinical data and all the pathological sections were reviewed, the related immunohistochemical results were statistically analyzed, the clinicopathological features were analyzed, and then followed the prognosis. Results: (1) Clinical features: the median onset age of BSCC in cervix was 51 years old (ranged 35-69 years old), 5 of them were postmenopausal women. Vaginal bleeding was often seen in clinic (7 cases). Of the 10 cervical BSCC patients, 5 tested HPV types. All of them were HPV positive, including 2 cases of HPV 16 positive and 1 case of high-risk HPV positive. At the time of colposcopy, 3 cases showed exogenous nodular mass, 3 cases showed endogenous infiltrating mass, and 4 cases had unclear type of mass.(2)Treatment: of the 10 patients, 8 underwent hysterectomy+bilateral adnexal excision+pelvic lymphadenectomy, of which 6 underwent radiotherapy or chemotherapy after operation.Radiotherapy and chemotherapy were performed only in 2 cases. (3) Pathological features: histologically, the tumor cells were nests and stripe like growth, which were composed of basal like tumor cells. The cells had obvious heteromorphosis, less cytoplasm, deep dyed nuclei and common nuclear mitosis, and there were often palisade like structures around the cell nests, and some cells in the center of the cell nests were found to have acne like necrosis. It could be mixed with normal squamous cell carcinoma and squamous epithelial lesion. Among the 10 patients, 6 had immunohistochemical results. BSCC mainly expressed p16 and squamous cell markers such as p63, cytokeratin (CK) 5/6 and p40 protein, the positive expression rates were 3/3, 3/3, 2/2 and 3/3, respectively. A few expressed CK7 protein, and the positive expression rate was 1/3. (4) Prognosis: follow-up time ranged from 1 week to 64 months, and 2 cases were lost to follow-up. Among the 8 follow-up patients, 3 had iliac bone, lung or skin metastasis, and 5 had no recurrence or metastasis during the follow-up period. Conclusions: BSCC of cervix is a rare malignant tumor of cervix associated with high-risk HPV infection, p16 is more positive. The treatment is similar to that of normal cervical squamous cell carcinoma. Surgical resection and radiotherapy and chemotherapy are the most effective methods according to the clinical stage. At present, the disease is considered to be highly aggressive and the poor prognosis.

Therapeutic effect of ginsenoside Rg1 on mastitis experimentally induced by lipopolysaccharide in lactating goats

Escherichia coli is a cause of subclinical and clinical mastitis in dairy cattle and goats, and sometimes causes severe clinical disease that may result in death of the animal. Previous investigation showed that ginsenoside Rg1 extracted from Panax ginseng C.A. Meyer (Araliaceae) has an anti-inflammatory effect on the sepsis induced by E. coli lipopolysaccharide via competitive binding to toll-like receptor 4. We hypothesized that intravenous injection of Rg1 had therapeutic effect on mastitis experimentally induced by intramammary infusion of lipopolysaccharide in lactating goats. In this study, 9 lactating goats were randomly assigned to 1 of the 3 groups: (1) lipopolysaccharide intramammary infusion + saline intravenous injection, (2) lipopolysaccharide intramammary infusion + Rg1 intravenous injection, and (3) saline intramammary administration + saline intravenous injection. Because no adverse clinical signs were observed after intramammary infusion of saline and intravenous injection of Rg1 in a preliminary experiment, and available qualified goats were limited in this study, this treatment was not included in this study. One udder half of each goat received intramammary infusion of lipopolysaccharide (50 μg/kg of body weight; groups 1 and 2) or saline solution (group 3), and the other half was infused with 2 mL of saline solution at h 0. Afterward, intravenous injections of saline solution (groups 1 and 3) or Rg1 (2.5 mg/kg of body weight; group 2) were administered at h 2 and 4 post-lipopolysaccharide challenge. Blood and milk samples were collected 3, 6, 9, 12, 15, 18, 21, 24, 48, and 72 h post-lipopolysaccharide challenge, and clinical signs were monitored hourly after lipopolysaccharide challenge within the first 10 h and at the same time points as blood samples. The results showed that Rg1 treatment downregulated rectal temperature, udder skin temperature, udder girth, milk somatic cell count, and N-acetyl-β-d-glucosaminidase and upregulated milk production, lactose, and recovered blood components, such as white blood cells, neutrophils, lymphocytes, total proteins, albumin, and globulin. Considering the positive therapeutic effect on lipopolysaccharide-induced mastitis in goats presented in this study as well as the anti-inflammatory activity found previously, the botanical Rg1 deserves further study as a therapeutic agent in the treatment of E. coli mastitis in dairy animals.

Measurement of the Electron Antineutrino Oscillation with 1958 Days of Operation at Daya Bay

We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor ν[over ¯]_{e} inverse β decay candidates observed over 1958 days of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic ^{9}Li and ^{8}He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative ν[over ¯]_{e} rates and energy spectra among detectors yields sin^{2}2θ_{13}=0.0856±0.0029 and Δm_{32}^{2}=(2.471_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the normal hierarchy, and Δm_{32}^{2}=-(2.575_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the inverted hierarchy.

Two dcm Gene Clusters Essential for the Degradation of Diclofop-methyl in a Microbial Consortium of Rhodococcus sp. JT-3 and Brevundimonas sp. JT-9

The metabolism of widely used aryloxyphenoxypropionate herbicides has been extensively studied in microbes. However, the information on the degradation of diclofop-methyl (DCM) is limited, with no genetic and biochemical investigation reported. The consortium L1 of Rhodococcus sp. JT-3 and Brevundimonas sp. JT-9 was able to degrade DCM through a synergistic metabolism. To elaborate the molecular mechanism of DCM degradation, the metabolic pathway for DCM was first investigated. DCM was initially transformed by strain JT-3 to diclofop acid and then by strain JT-9 to 2-(4-hydroxyphenoxy) propionic acid as well as 2,4-dichlorophenol. Subsequently, the two dcm gene clusters, dcmAE and dcmB1B2CD, involved in further degradation of 2,4-dichlorophenol, were successfully cloned from strain JT-3, and the functions of each gene product were identified. DcmA, a glutathione-dependent dehalogenase, was responsible for catalyzing the reductive dehalogenation of 2,4-dichlorophenol to 4-chlorophenol, which was then converted by the two-component monooxygenase DcmB1B2 to 4-chlorocatechol as the ring cleavage substrate of the dioxygenase DcmC. In this study, the overall DCM degradation pathway of the consortium L1 was proposed and, particularly, the lower part on the DCP degradation was characterized at the genetic and biochemical levels.

[Comparison of epidermal growth factor receptor gene mutation in lung adenocarcinoma using biopsied tissue, pleural effusion and blood samples]

Objective: To compare different specimen types of lung adenocarcinoma in the detection of epidermal growth factor receptor (EGFR) gene and to correlate EGFR mutations with patient clinical features. Methods: One hundred lung adenocarcinoma cases were collected from June to December in 2015, at the First Affiliated Hospital of Xinjiang Medical University.Of the 100 lung adenocarcinoma samples, 43 were male and 57 were female. The age was from 40 to 88 years old, and the average age was 66 years. One hundred lung adenocarcinoma cases were divided equally into two groups. Mutation analysis of EGFR gene by real-time PCR was performed using biopsied tissue and paired blood samples in one group (n=50) and using pleural effusion and paired blood samples in the other group (n=50). Results: The mutation rate of EGFR gene in biopsy samples was 54% (27/50) , higher than that of blood samples (46%, 23/50), but without statistical differences (χ(2)=0.640, P=0.424). In contrast, mutation rate of EGFR gene in pleural effusion samples (42%, 21/50) was higher than that of blood samples (34%, 17/50), but without statistical differences(χ(2)=0.679, P=0.409). Two patients had EGFR mutation detected in paired blood samples but not in the corresponding biopsy samples, and four patients had EGFR mutation detected in pleural effusion samples but not in their paired blood samples. The mean progression-free survival of patients with detectable EGFR mutation were 9.5 months (tissue samples), 8.6 months (pleural effusion) and 8.5 months (blood). However, there was no statistical difference. Conclusions: Blood samples may be used to assess EGFR mutations for patients with lung adenocarcinoma. However, further studies are needed to improve the sensitivity and accuracy in the detection of EGFR mutations using blood samples.

[Distribution of Phosphorus Fractions in Surface Sediments of Minjiang Mainstreams]

In recent years, the total phosphorus pollution in Minjiang River was serious, and the surface sediments of the Minjiang River also threatened water quality. To study the spatial distributions of phosphorus in the surface sediments of the Minjiang River, samples of surface sediments were collected upstream (Aba District) and downstream (Yibin District) of the Minjiang River in December, 2016. The sediments were analyzed with the modified sequential extraction method (SEDEX) to obtain six forms of phosphorus, including exchangeable phosphorus (Ex-P), exchangeable organic phosphorus (Org-P), iron-bound phosphorus (Fe-P), authigenic phosphorus (Ca-P), detrital phosphorus (De-P), and refractory phosphorus (Res-P). The results indicated that the contents of total phosphorus (TP) in surface sediments ranged from 522.17 μg ·g^-1 to 979.22 μg ·g^-1, which were far more than the soil phosphorus background values (700 μg ·g^-1). The spatial distribution characteristics of the TP of surface sediments indicated that the TP concentrations in sediments at the Meishan sections (the middle reach of the Minjiang River) were higher than those in the other sections. This was related to the smaller particle size and higher OM contents in sediments in the Meishan sections. The main phosphorus forms in the sediments in the Minjiang River were Ca-P and De-P, with their concentrations accounting for 75% of TP in the sediments. The bio-available phosphorus, which included Ex-P, Org-P, and Fe-P, accounted for 0.31%-29.62% of TP in the sediments of the Minjiang River. The concentrations of bio-available phosphorus in sediments at the Meishan sections and Leshan sections (the middle reach) were highest, indicating that bio-available phosphorus in the surface sediments was high, and its potential environmental impact risks were higher.

Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

Infrared optical constants of liquid palm oil and palm oil biodiesel determined by the combined ellipsometry-transmission method

The optical constants of vegetable oils and biodiesels are the basic input parameters in the study of the thermal radiation transfer and monitoring the productivity of vegetable oils converting to biodiesels. In this work, a combined ellipsometry-transmission method is presented to obtain the optical constants of palm oil and palm oil biodiesel between 20°C and 150°C in the spectral range 600-4100  cm^-1 and to study the temperature effect on the optical constants. In the combined method, a modified ellipsometry method is used to measure the optical constants of palm oil and palm oil biodiesel for the whole researched wave bands. For the weak absorption regions in which the ellipsometry method cannot give precise absorption indices, the transmission method is conducted to get the absorption indices using the refractive indices obtained by the proposed ellipsometry method. Deionized water and methanol are taken as examples to verify the combined ellipsometry-transmission method. It is shown that the combined method can overcome the deficiencies of the traditional ellipsometry and transmission method, which can be used for the measurements of both strong and weak absorption wave bands. The experimental analyses indicate that temperature exerts a noticeable influence on the infrared optical constants of palm oil and palm oil biodiesel. With the increase of temperature, the refractive indices at certain wavenumbers decrease nearly linearly, and the amplitudes of dominant absorption peaks show a decreasing trend. The absorption peaks located around 3550  cm^-1 show blueshift trends as temperature increases. Comparing these two kinds of oils, palm oil presents larger values in refractive indices and dominant absorption peaks.

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}<0.8  eV^{2} at 95%  CL_{s}.

Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

[Response Behaviors of Heavy Metals at Tidal Currents Interface and Salinity Interface in the Estuary Area]

In China, trace metals (such as dissolved Cu, Zn, Pb, Cd, and Cr) are the routine mandatory monitoring indicators in existing Freshwater Quality Standard (FWQS, 2002) and Seawater Quality Standard (SWQS, 1997). Using Daliao River estuary as an example, we tried to research the general response patterns of these metals in estuarine system. Firstly, we determined the location of FSI (freshwater-seawater interface) and TCI (tidal currents interface), which were based on biological, chemical and geographic similarities by descriptive and quantitative methods, respectively. Secondly, two hypotheses were proposed to explain the difference based on distribution coefficient K_d along salinity and SS (suspended solids) gradient, these results revealed that the indicators for As, Cd and Cr may be prone to be affected by salinity, and the ones in the second pattern may be more sensitive to SS. Finally, we classified the response behaviors into two patterns based on the changing trends along the distance and magnitudes affected by the FSI and TCI: 1the obvious boundary break point from FSI for As, Cd and Cr; 2 the boundary zones from TCI for Zn, Cu, Pb and Ni. The partitioning behaviors showed similar changing trends at particle and sediment phases, especially for particle phase, depending on the concentration of SS along the salinity. The difference between general behaviors for the two patterns mainly existed at water phase. In general, this paper highlighted the need to consider the background difference of trace metals and identified the sensitive indicators controlled by different environment factors (such as salinity and SS) based on the native estuarine characteristics. Our work will assist the implementation of updating the current water quality standards in China.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Simultaneous effects of surface spins: rarely large coercivity, high remanence magnetization and jumps in the hysteresis loops observed in CoFe2O4 nanoparticles

Well-dispersed uniform cobalt ferrite nanoparticles were synthesized by thermal decomposition of a metal-organic salt in organic solvent with a high boiling point. Some of the nanoparticles were diluted in a SiO2 matrix and then the undiluted and diluted samples were characterized and their magnetic behavior explored. The undiluted and diluted samples exhibited maximum coercivity Hc of 23,817 and 15,056 Oe at 10 K, respectively, which are the highest values reported to date, and the corresponding ratios of remanence (Mr) to saturation (Ms) magnetization (Mr/Ms) were as high as 0.85 and 0.76, respectively. Interestingly, the magnetic properties of the samples changed at 200 K, which was observed in magnetic hysteresis M(H) loops and zero-field cooling curves as well as the temperature dependence of Hc, Mr/Ms, anisotropy, dipolar field, and the magnetic grain size. Below 200 K, both samples have large effective anisotropy, which arises from the surface spins, resulting in large Hc and Mr/Ms. Above 200 K, the effective anisotropy decreases because there is no contribution from surface spins, while the dipolar interaction increases, resulting in small Hc and Mr/Ms. Our results indicate that strong anisotropy and weak dipolar interaction tend to increase Hc and Mr/Ms, and also clarify that the jumps around H = 0 in M(H) loops can be attributed to the reorientation of surface spins. This work exposes the underlying mechanism in nanoscale magnetic systems, which should lead to improved magnetic performance.

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9  GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3)  eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

[Temporal-spatial distribution and pollution assessment of heavy metals in the upper reaches of Hunhe River (Qingyuan section), northeast China]

The aim of this article is to explore the pollution level and contamination degree of heavy metals in the upper reaches of Hunhe River (Qingyuan Section). The contents and temporal-spatial distribution of Fe, Mn, Cu, Zn, Cd and As in surface water and surface sediments from the upper reaches of Hunhe River were analyzed respectively. The integrated pollution index and geoaccumulation index were used to evaluate the contamination degree of Cu, Zn, Cd and As. The results indicated that the contents of Mn, Cu, Zn, Cd and As in surface water from the upper reaches of Hunhe River during the wet season were higher than those during normal and dry season. Similar patterns of spatial distribution of Fe, Mn, Cu, Zn and Cd in surface water were observed, which showed that the highest content appeared at H7 station. The influence of pH, DO and hardness in the upper reaches of Hunhe River during the wet, normal and dry season on the distribution of heavy metal contents in surface water varied. Significant positive correlations were found among these elements in surface water, which implied that these elements probably had common pollution sources. The contents of Cu, Zn, Cd and Fe in surface sediments from the upper reaches of Hunhe River during the dry season were higher than those during the wet and normal season. Similar patterns of spatial distribution of Mn, Cu, Zn, As and Cd in surface sediments were also observed, which showed that the highest metal contents appeared in the midway of Hunhe River. The integrated pollution index assessment showed that the water quality in the upper reaches of Hunhe River was good except for individual stations, and that Cu, Cd and As were the main pollution elements in surface sediments in the upper reaches of Hunhe River.

Observation of electron-antineutrino disappearance at Daya Bay

The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GWth reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43,000 ton-GWth-day live-time exposure in 55 days, 10,416 (80,376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940±0.011(stat.)±0.004(syst.). A rate-only analysis finds sin(2)2θ(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework.

Analysis of molluscicide metaldehyde in vegetables by dispersive solid-phase extraction and liquid chromatography-tandem mass spectrometry

This paper describes the development and validation of a new reverse-phase liquid chromatography-electrospray ionisation tandem mass spectrometric method (RP-HPLC-ESI-MS/MS) for the determination of metaldehyde in different kinds of vegetables. Metaldehyde was extracted with 20 ml acetonitrile from 10 g vegetable and followed by dispersive solid-phase extraction (Bondesil-primary secondary amine, PSA). The identification of metaldehyde was established by chromatographic retention times, analyte-specific fragmentation patterns and relative peak area ratios of two precursor/product ion pairs. The limit of detection of this method was 0.01 mg kg(-1) using an injection volume of 5 µl. The repeatability of this method is excellent and the relative standard deviation (RSD) is less than 4%.

Monomer-dimer reaction model with asymmetric adsorption of monomer and dimer on the catalyst surface

The irreversible kinetics of the Ziff-Gulari-Barshad model in the presence of inhomogeneity on a catalyst surface is investigated by means of Monte Carlo simulation. We assume that only part of catalyst surface sites are active for surface catalytic reaction and randomly distributed on the catalyst surface. The adsorption of a O2 molecule is permitted if one site of a nearest-neighbor vacant pair is active. CO can adsorb on all vacant sites, but the adsorption probability is p(p<1) if the site is not active. In our modified model, the O-passivated phase disappears and the continuous phase transition between the O passivated and the reactive state is eliminated. We also find that the transition between the CO passivated and the reactive state is continuous if the concentration of the active sites is small, and it becomes discontinuous with increasing concentrations of active sites. Furthermore, it is shown that a hysteresis loop exists whether the CO-passivated transition is continuous or discontinuous. Our simulation results are in good agreement with many relevant experimental results and may provide an alternative explanation for the experimental observations.

[Protection against paracetamol-induced hepatic damage using total flavonoids of Astragalus]

OBJECTIVE

To study the mechanism of the protection by total flavonoids of Astragalus protection against paracetamol-induced hepatic damage.

METHOD

Analysing paracetamol and its metabolites in mice urine by HPLC and studying the mechanism of anti-damage induced by paracetamol using experiment module of pentobarbital-induced sleeping time.

RESULT

Administration of large doses of paracetamol to C57BL/6J mice produced significant hepatic injury with marked elevation in serum ALT activity and severe hepatocellular necrosis. TFA showed a good protective capability against paracetamol-induced hepatic injury. TFA had no marked effect on paracetamol and its metabolites except for the mercapturate-conjugate. The concentration of mercapturate change decreased with increasing TFA dose. TFA had no effect on the pentobarbital metabolites (P > 0.05). However, paracetamol (400 mg.kg-1) prolonged the sleeping time (by 110 min relative to the controls, P < 0.001). The TFA (P < 0.005) caused significant reduction in paracetamol-prolonged pentobarbital-induced sleep.

CONCLUSIONS

The mechanism of TFA's protective effect against the paracetamol-induced damage may be related to the inhibition of some metabolism progress of paracetamol and the reduction of the toxicity metabolite such as mercapturate-conjugate.

[Studies on protective effect of total flavonoids of Astragalus on liver damage induced by paracetamol]

OBJECTIVE

To study the protective effect of total flavonoids of Astragalus (TFA) on the liver against large doses of paracetamol in mice.

METHOD

After oral administration of TFA or Vitamin C 1 h prior to giving large dose of paracetamol in mice, the changes of paracetamol-induced mortality rate, serum enzyme level and liver damage degree were observed.

RESULT

Paracetamol produced 80% mortality, within 24 hours of the administration of a dose of 1000 mg.kg-1 to the mice. Pre-treatment of the animals with TFA (100 mg.kg-1) or Vitamin C (1,000 mg.kg-1) reduced the death rate to 20% and 0% respectively. There was also a significant rise in the serum enzyme level of alanine transaminase (P < 0.001) and the area of liver necrosis (P < 0.001), 24 h after paracetamol (400 mg.kg-1) treatment. With pre-treatment with either TFA or Vitamin C, there was an obvious dose-dependent decrease in ALT levels and the area of hepatocellular necrosis.

CONCLUSION

TFA has potential protecting effect against the paracetamol-induced hepatic damage.

Entropy-driven phase transition in binary mixtures

Based on the principle of entropy maximum, a transparent method to study the phase separation is proposed. The excluded volume effects of binary mixtures of hard spheres with two different diameters are analyzed and the role of entropy is emphasized. As a result of the entropy variation caused by the packing of large spheres, there is a critical volume fraction to denote the phase boundary. It is shown that the variation of free volume fraction is influenced by the ratio alpha=d(L)/d(S) of large to small sphere diameters and the ratio x=eta(L)/(eta(L)+eta(S)) of large-sphere volume fraction to the total volume fraction of large- and small-spheres. We introduce a modification factor beta to describe the overlap degree of two large spheres excluded volumes when they pack together. The critical volume fractions for large-sphere packing with different values of alpha and x are calculated, and the corresponding phase boundaries are determined. Our results are in quite good agreement with previous experimental measurements.

Effect of Imidacloprid on Incidence of Tomato yellow leaf curl virus

Confidor, an imidacloprid insecticide, was used in two applications at four rates (47.6, 71.4, 95.2, and 119 g a.i./ha) for indirectly controlling Tomato yellow leaf curl virus (TYLCV) in field plantings of tomato. This spray regimen was compared with standard applications of cypermethrins at 10- to 15-day intervals throughout the growing season. In three field trials, a combination of integrated pest management (IPM) practices and two applications of Confidor at the two highest rates immediately after planting and 6 weeks later, protected tomato plants against the disease until 12 weeks after sowing. All rates of Confidor reduced disease incidence compared with standard chemical control applied in an integrated strategy, and quantitative efficacy increased with increase of insecticide rate. In the three seasons, the mean incidence of TYLCV 12 weeks after sowing was 42.7% in plots not adopting IPM compared with 15.7% in those that did. Disease incidence was reduced by Confidor treatments to 2.2 to 17%. Confidor-treated plots consistently had higher yields than control plots, and the yields decreased with the decrease in the rate of Confidor application. Confidor offers several advantages over standard applications of cypermethrins to control TYLCV. When applied immediately after planting, its long-lasting systemic activity protected the crop against the disease during early stages of growth. In addition, it reduced the number of sprays and increased tomato yield.

[Molecular tagging of a new recessive gene for late heading in a rice cultivar 8987]

8987 is a late flowering (lf) indica cultivar. In this study, genetic analysis for lf was carried out in the crosses between 8987 and four varieties with different heading time. Inheritance of lf in F1 plants and F2 populations clearly revealed that the lf of 8987 is controlled by one recessive gene. Bulked-segregant method and cosegregation analysis in F2 population were used to screen molecular markers, which were linked with lf gene. The results showed that the lf gene was mapped between the two RFLP marker C213 and RG404 on chromosome 7. The tagged gene will be utilized in molecular marker assisted selection in the future rice breeding program for new varieties.

Heparan sulfate-like proteoglycans mediate adhesion of human malignant melanoma A375 cells to P-selectin under flow

Selectins, a family of cell adhesion molecules, bind to sialylated and fucosylated carbohydrates, such as sialyl Lewisx (SLex) and its derivatives, as their minimal recognition motif. Here we report that P-selectin bound to human malignant melanoma A375 cells and mediated their adhesion under flow. However, probing with a specific Ab failed to detect any apparent expression of SLex. This finding was bolstered by reduced expression of alpha-1,3-fucosyltransferase VII mRNA and by absence of the cell surface expression of P-selectin glycoprotein ligand-1. Instead, they expressed heparan sulfate-like proteoglycans on their cell surfaces. Treatment with beta-d -xyloside (a proteoglycan biosynthesis inhibitor) or heparinases could reduce the binding of these cells to P-selectin. In the competition assays, heparin, but not other proteoglycans, could abolish the P-selectin recognition. Further, we found that P-selectin could bind specifically to human tongue squamous cancer Tca-8113 cells, which had negative staining of SLex but positive staining of heparan sulfates. Both beta-d -xyloside and heparinases could reduce the binding of P-selectin to Tca-8113 cells. Our results thus indicate that heparan sulfate-like proteoglycans can mediate adhesion of certain types of non-blood borne, "epithelial-like" human cancer cells to P-selectin.

[Spectrum distribution of ultra-weak luminescence of blood in lung cancer patients]

Using the single-photon counting detecting system manufactured by the Institute of Biophysics, Academia Sinica, the emission spectrum of ultra-weak luminescence of blood from 10 normal blood donors and 37 lung cancer patients were studied. The experimental results showed that ultra-weak photon emission of patients' was originated from the red region and three emission peaks were observed at 425-460, 535-595 and 620-660 nm. The intensity of photon emission at 425-460 nm of patient's blood was markedly higher than that of normal blood donors, with statistical significance. Furthermore, after operation, the spectrum distribution almost returned to that of what was seen in normal blood donors. Our observation shows that ultra-weak luminescence of blood may serve as an early detection of lung cancers.

[Morphological observation of termination of early pregnancy with anordrin in mice]

Twenty four mice were divided randomly into experimental and control groups. There were 10 animals in the control group. In experimental group, anordrin (3 mg/kg) was injected into the peritoneal cavity to terminate early pregnancy. The control group was treated with normal saline. Pathological changes in the decidual cells, blastocysts (including giant cells), corpora lutea and embryo were observed. It was found that the animals in the control group were developing normally. In all the experimental groups decidual cells and blastocysts showed degeneration and necrosis. The granulosa lutein cells also showed degeneration. The dead embryo was embedded in the necrotic decidual cells and blastocysts. The mechanism concerned may involve a combination of various factors. The degeneration of granulosa lutein cells may be the most important of the factors.