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.

Endovascular treatment of aortic saddle embolism through percutaneous mechanical Thrombectomy via Straub Rotarex catheter

BACKGROUND

To summarize our experience of endovascular treatment for abdominal aorta saddle embolism (ASE) through percutaneous mechanical thrombectomy (PMT).

METHODS

Clinical data of three ASE patients treated with an endovascular approach using percutaneous mechanical thrombectomy (PMT) were reviewed and analyzed.

RESULTS

After PMT, blood flow of limbs was restored in all of the three patients. However, two patients died from sudden cardiac arrest caused by hyperkalemia several hours after the procedure. The other one patient survived through continuous renal replacement therapy, which was initialized shortly after the surgical procedure.

CONCLUSION

Endovascular treatment through PMT can quickly restore blood flow in the ASE patients. Blood purification through renal replacement therapy is crucial to reduce mortality after restoring blood flow of the limbs.

Endovascular therapy for floating thrombus in the inferior vena cava

Objective

We aimed to summarize the clinical characteristics of floating thrombus in the inferior vena cava (IVC).

Methods

From January 2014 to June 2019, four patients with floating thrombus in the IVC were admitted to our hospital and underwent intracavitary therapy. Diagnosis, therapy, and clinical characteristics of floating thrombus were summarized.

Results

Three patients presented with pulmonary embolism. Three of the patients had a floating thrombus discovered by inferior venacavography and one was found by contrast-enhanced computed tomography. Two patients had deep venous thrombosis in the lower extremities. One patient had a double IVC, one had left iliac vein compression syndrome, and one had right renal phlebothrombosis. The four patients underwent implantation of a temporary IVC filter and were treated with anti-coagulation, debulking, and thrombolysis. All four patients achieved satisfactory results.

Conclusions

Floating thrombus in the IVC is often caused by spread of branch vein thrombosis, and is more likely to lead to pulmonary embolism. Anti-coagulant therapy and debulking under the protection of filters can achieve satisfactory clinical results.

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}.

Positive-Parity Linear-Chain Molecular Band in ^{16}C

An inelastic excitation and cluster-decay experiment ^{2}H(^{16}C,^{4}He+^{12}Be or ^{6}He+^{10}Be)^{2}H was carried out to investigate the linear-chain clustering structure in neutron-rich ^{16}C. For the first time, decay paths from the ^{16}C resonances to various states of the final nuclei were determined, thanks to the well-resolved Q-value spectra obtained from the threefold coincident measurement. The close-threshold resonance at 16.5 MeV is assigned as the J^{π}=0^{+} band head of the predicted positive-parity linear-chain molecular band with (3/2_{π}^{-})^{2}(1/2_{σ}^{-})^{2} configuration, according to the associated angular correlation and decay analysis. Other members of this band were found at 17.3, 19.4, and 21.6 MeV based on their selective decay properties, being consistent with the theoretical predictions. Another intriguing high-lying state was observed at 27.2 MeV which decays almost exclusively to ^{6}He+^{10}Be(∼6  MeV) final channel, corresponding well to another predicted linear-chain structure with the pure σ-bond configuration.

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.

[Application of image-guided system in endoscopic sinus and skull base surgery]

Objective:To evaluate the applicative value of image-guided system in endoscopic sinus and skull base surgeries. Method:A total of 103 endoscopic surgical procedures were performed.All these procedures were conducted with the utilization of image-guided system, among which there were 92 cases of sinonasal-skull base surgery(including nasal sinuses resection of benign and malignant tumors involving skull base lesions, the cumulative orbital lesion resection of nasal sinus lesions, etc. ), 6 repair of cerebrospinal fluid leak, 3 pituitary adenoma resection, 2 traumatic neuropathy optic nerve decompression. Result:With the utilization of image-guided system, all patients had successful surgery without major and minor complications. The image-guided system provided high precision with short registration time. Conclusion:Image-guided system can help the surgeon to identify accurately the vital anatomic landmarks of sinus and skull base, improving surgical accuracy and safety as well as reducing or avoiding the intraoperative and postoperative complications.

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.

[The study of growth differentiation factor-15 in chronic thromboembolic pulmonary hypertension following acute pulmonary thromboembolism]

Objective: To evaluate the incidence of chronic thromboembolic pulmonary hypertension (CTEPH) secondary to acute pulmonary thromboembolism (PTE) and the serum level of growth differentiation factor-15(GDF-15). Methods: Ninety-six acute PTE patients were recruited in the study. Clinical data, Wells score, blood gas analysis, D-dimmer level, GDF-15 level, atrial and ventricular sizes, pulmonary arterial systolic pressure (PASP) and pulmonary artery CT (CTPA) data were collected. Patients were followed up to evaluate the cardiac function (WHO class), ultrasonic cardiogram and CTPA to confirm the incidence of CTEPH. Results: Eighty-fivepatients were followed for 5 months to 58 months (average 26.5±14.7 months). The incidence of CTEPH was 12.9% (11/85). Between CTEPH patients and non-CTEPH patients, PASP, right atrial and ventricular sizes, and GDF-15in the acute stage were significantly different(P<0.05). According to binary logistic regression analysis, the incidence of CTEPH was correlated positively with acute PASP and the serum level of GDF-15. Conclusions: The incidence of CTEPH in acute PTE patients was 12.9% in this study. Acute PASP and higher level of GDF-15 are predictive factors for CTEPH secondary to acute PTE.

[Co-overexpression of human tissue kallikrein 1 and human metalloproteinase 1 tissue inhibitor inhibits neointima formation in the rat artery after balloon angioplasty]

OBJECTIVE

To investigate the effects of adenovirus-mediated human tissue kallikrein 1(hTK-1) and/or human tissue metalloproteinase inhibitor 1 (hTIMP-1) gene delivery on the neointima formation in balloon-injured rat carotids and related mechanism.

METHODS

Forty-six male Sprague-Dawley rats were randomly assigned into 6 groups with the random number table: (1) sham-operated group(n=6), (2) angioplasty group (n=8), (3) vector virus group (n=8), (4) hTK-1 group (n=8), (5) hTIMP-1 group (n=8), (6) hTK-1-hTIMP-1 group (n=8). Except sham rats, all rats underwent carotid artery balloon injury and local delivery of saline or different recombined adenoviruses respectively. Rats were sacrificed 14 days later. Intima/media area ratio was assessed on hematoxylin-eosin stained tissue section. Immunofluorescence images stained for hTK-1, hTIMP-1 were obtained and analyzed by the confocal microscope for co-localization examination of hTK-1 and hTIMP-1. The protein expression levels of hTK-1, hTIMP-1, matrix metalloproteinases(MMP)-2 and MMP-9 were determined by Western blot. Immune histochemical staining for PCNA was also performed.

RESULTS

(1)Intima area, intima/media area ratio, PCNA, MMP-2 and MMP-9 levels were all significantly increased in rats underwent angioplasty (did or did not receive vector virus) compared with sham-operated rats (all P<0.01) while above parameters were similar between rats underwent angioplasty or vector virus delivery (all P>0.05). (2) The intima area of rats received vector virus, hTK-1, hTIMP-1 or dual gene transfer were (0.160±0.010), (0.110±0.015), (0.121±0.016) or (0.081±0.008) mm(2) respectively, intima area was similar between rats received hTK-1 or hTIMP-1 (P>0.05), differences were found between other groups (all P<0.01). The intima/media area ratio of rats received vector virus, hTK-1, hTIMP-1 or dual gene transfer were 2.035±0.117, 1.443±0.097, 1.522±0.078 or 0.972±0.072 respectively, no difference was found between rats received hTK-1 or hTIMP-1 in intima/media area ratio (all P>0.05), differences were found between other groups (all P<0.01). The MMP-2 and MMP-9 expression of rats received vector virus, hTK-1, hTIMP-1 or dual gene transfer were 0.817±0.036, 0.606±0.044, 0.571±0.061 or 0.455±0.030 and 0.745±0.057, 0.613±0.038, 0.582±0.050 or 0.473±0.038 respectively, no difference was found between rats received hTK-1 or hTIMP-1 in MMP-2 or MMP-9 expression (all P>0.05), differences were found between other groups (all P<0.01). The PCNA expression of rats received vector virus, hTK-1, hTIMP-1 or dual gene transfer were 0.065±0.007, 0.052±0.004, 0.055±0.007 or 0.031±0.004 respectively, no difference was found between rats received hTK-1or hTIMP-1 in PCNA expression (all P>0.05), differences were found between other groups (all P<0.01).

CONCLUSION

hTK-1 and hTIMP-1 co-overexpression may synergistically inhibit neointimal hyperplasia, attenuate vascular remodeling and reduce restenosis possibly via down regulating the expressions of PCNA, MMP-2 and MMP-9 in balloon-injured rat carotids.

SERS Titration of 4-Mercaptopyridine Self-Assembled Monolayers at Aqueous Buffer/Gold Interfaces

Determination of the surface pK(a) of self-assembled monolayers (SAMs) at aqueous buffer/gold interfaces using surface-enhanced Raman scattering (SERS) measurements, namely, SERS titration, is reported for the first time. From the analysis of pH-dependent SERS spectra of 4-mercaptopyridine monolayers on gold, the pK(1/2) (3.9 ± 0.2) was determined. By further correlating the surface pH value with the bulk pH value in terms of the Gouy-Chapmann model, the surface pK(a) (5.3 ± 0.3) was evaluated accordingly. Compared to the conventional contact angle titration, SERS titration has the advantage of giving further insight into the microscopic and dynamic information of the surface-confined functional groups. In addition, such a technique has high sensitivity, micrometer spatial resolution, and chemical selectivity.

Self-assembly on "recordable CDs"

Gold substrates for self-assembly were constructed from recordable compact disks (CD-Rs) with simple and straight-forward wet-chemical treatment. In particular, they were made into desired sizes and shapes that satisfy different experimental needs. Self-assembled monolayers (SAMs) of long-chain alkanethiols (e.g., n-C18H37SH) adsorbed on gold substrates prepared from CD-Rs have been characterized by wetting measurements, electrochemistry, infrared (IR) spectroscopy, and scanning tunneling microscopy (STM). The results showed that there were no distinct differences in the quality and structure between these monolayers and SAMs formed on standard gold substrates (i.e., prepared from vacuum evaporation of pure gold onto glass slides). The present work demonstrates the applicability of recordable CDs as inexpensive, simple, and versatile gold substrates for self-assembly studies.

Triacylglycerols of the red microalga Porphyridium cruentum can contribute to the biosynthesis of eukaryotic galactolipids

A mutant of the red microalga Porphyridium cruentum was selected on the basis of impaired growth at suboptimal temperatures (15 vs. 25 degrees C). Fatty acid and lipid analyses revealed diminished proportions of eicosapentaenoic acid (from 41 to 30%) and of the eukaryotic molecular species (from 38 to 28% of monogalactosyldiacylglycerol (MGDG) and elevated proportion (10 vs. 2%) of triacylglycerols (TAG) in the mutant, as compared with the wild type. Pulse labeling of the wild type cells with radioactive fatty acid precursors indicated an initial incorporation of the fatty acids into phosphatidylcholine (PC) and TAG. Following the pulse, the label of PC and TAG decreased with time (from 25 to 5% of the total dpm in TAG) while that of chloroplastic polar lipids, mainly MGDG, continued to increase. In the mutant, however, the labeling of TAG after the pulse was higher (30% of the total dpm) than that of the wild type and decreased only slightly to 20%. This may indicate that in P. cruentum, TAG can contribute to the biosynthesis of eukaryotic species of MGDG.

SERS Titration of 4-Mercaptopyridine Self-Assembled Monolayers at Aqueous Buffer/Gold Interfaces

Determination of the surface pK(a) of self-assembled monolayers (SAMs) at aqueous buffer/gold interfaces using surface-enhanced Raman scattering (SERS) measurements, namely, SERS titration, is reported for the first time. From the analysis of pH-dependent SERS spectra of 4-mercaptopyridine monolayers on gold, the pK(1/2) (3.9 ± 0.2) was determined. By further correlating the surface pH value with the bulk pH value in terms of the Gouy-Chapmann model, the surface pK(a) (5.3 ± 0.3) was evaluated accordingly. Compared to the conventional contact angle titration, SERS titration has the advantage of giving further insight into the microscopic and dynamic information of the surface-confined functional groups. In addition, such a technique has high sensitivity, micrometer spatial resolution, and chemical selectivity.

[Tumor microvascular bed and its reactivity to vasoactive agents: measurement of tissue blood flow and patho-morphological study]

Structural characteristics of tumor microvascular bed and its reactivity to vasoactive agents were studied by histological and ultrastructural examination and tissue blood flow measurement. The results showed that newly formed vessels in the tumor tissue consisted of a single layer of endothelial cells with multi-layer basement membranes and a few pericytes. Smooth muscle cells and nerve endings were absent. The tissue blood flow in highly proliferative parts of tumors was relatively constant and not influenced by tumor size, even though the distribution of neovasculature in tumor tissue was very uneven in distribution. The only vasoactive agent which can selectively increase the tumor blood flow was angiotensin II, whereas other adrenergic vasoconstrictors did not show this action.

Partial protection from the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) by Pro-Leu-Gly-NH2(PLG; MIF-1)

The administration of MPTP to man and monkey has been shown to cause a neurotoxic effect on the nigrostriatal dopamine system. MPTP was injected in C57-BL black mice, 36 mg per kg for 7 days, which resulted in permanent reduction of dopamine and serotonin levels in the striatum. In the mice pretreated with PLG, although the striatal dopamine level was also reduced, mean dopamine and serotonin levels were significantly higher than in mice given MPTP alone. It is concluded that PLG could protect at least partially the neurotoxic effect of MPTP.