Three-Dimensional Polar Perovskites for Highly Sensitive Self-Driven X-Ray Detection

Three-dimensional (3D) organic-inorganic hybrid perovskites (OIHPs) have achieved tremendous success in direct X-ray detection due to their high absorption coefficient and excellent carrier transport. However, owing to the centrosymmetry of classic 3D structures, these reported X-ray detectors mostly require external electrical fields to run, resulting in bulky overall circuitry, high energy consumption, and operational instability. Herein, we first report the unprecedented radiation photovoltage in 3D OIHP for efficient self-driven X-ray detection. Specifically, the 3D polar OIHP MhyPbBr3 (1, Mhy=methylhydrazine) shows an intrinsic radiation photovoltage (0.47 V) and large mobility-lifetime product (1.1×10-3  cm2  V-1 ) under X-ray irradiation. Strikingly, these excellent physical characteristics endow 1 with sensitive self-driven X-ray detection performance, showing a considerable sensitivity of 220 μC Gy-1  cm-2 , which surpasses those of most self-driven X-ray detectors. This work first explores highly sensitive self-driven X-ray detection in 3D polar OIHPs, shedding light on future practical applications.

Chiral-Achiral Cations Intercalation Induced Lead-Free Chiral-Polar Hybrid Perovskites Enable Self-Powered X-Ray and Ultraviolet-Visible-Near-Infrared Photo Detection

Lead halide hybrid perovskites have made great progress in direct X-ray detection and broadband photodetection, but the existence of toxic Pb and the demand for external operating voltage have severely limited their further applications and operational stability improvements. Therefore, exploring "green" lead-free hybrid perovskite that can both achieve X-ray detection and broadband photodetection without external voltage is of great importance, but remains severely challenging. Herein, using centrosymmetric (BZA)3BiI6 (1, BZA = benzylamine) as a template, a pair of chiral-polar lead-free perovskites, (BZA)2(R/S-PPA)BiI6 (2-R/S, R/S-PPA = (R/S)-1-Phenylpropylamine) are successfully obtained by introducing chiral aryl cations of (R/S)-1-Phenylpropylamine. Compared to 1, chiral-polar 2-R presents a significant irradiation-responsive bulk photovoltaic effect (BPVE) with an open circuit photovoltage of 0.4 V, which enables it with self-powered X-ray, UV-vis-NIR broadband photodetection. Specifically, 2-R device exhibits an ultralow detection limit of 18.5 nGy s-1 and excellent operational stability. Furthermore, 2-R as the first lead-free perovskite achieves significant broad-spectrum (377-940 nm) photodetection via light-induced pyroelectric effect. This work sheds light on the rational crystal reconstruction engineering and design of "green" hybrid perovskite toward high-demanded self-powered radiation detection and broadband photodetection.

Regulating Circularly Polarized Light Detection via Polar-Phase Transition in Alternating Chiral-Achiral Cations Intercalation-Type Hybrid Perovskites

Circularly polarized light (CPL) detection has wide applications in many fields, where the anisotropy factor (gIph ) is an important indicator to characterize the CPL detection performance. So far, many materials with high gIph have been reported, however, the exploration of the regulation of gIph is still in its infancy. Herein, two novel alternating chiral-achiral cations intercalation-type chiral hybrid perovskites (CHPs), named (R/S-1-phenylpropylamine)(propylamine)PbBr4 (1-R/S), exhibit above room-temperature (RT) polar-phase transition, which greatly regulates the gIph value. The gIph of 1-R is 0.04 in high-temperature phase chiral non-polar (P21 21 21 ) by applying 5 V bias, interestingly, with the temperature decrease, the gIph value in low-temperature phase chiral polar (P21 ) gradually increases (0.22@360K, 0.40@340K, 0.47@320K), and finally reaches a maximum of 0.5 at RT. Such value is not only the highest among 2D CHPs to date, but presents a 12.5-fold amplification compared with 0.04. Further, this rare phenomenon should be attributed to the built-in electric field induced by the polar photovoltaic effect, which sheds light on further obtaining CHPs with large gIph .

Circularly Polarized Light-Dependent Pyro-Phototronic Effect from 2D Chiral-Polar Double Perovskites

Chiral hybrid perovskites combine the advantages of chiral materials and halide perovskites, offering an ideal platform for the design of circularly polarized light (CPL) detectors. The pyro-phototronic effect, as a special mechanism of the photoexcited pyroelectric signal, can significantly improve the performance of photodetectors, whereas it remains a great challenge to achieve pyroelectricity-based CPL detection. In this work, the chiroptical phenomena and the pyro-phototronic effect are combined in chiral-polar perovskites to achieve unprecedented pyroelectric-based CPL detection. Two novel two-dimensional (2D) lead-free chiral-polar double perovskites, S/R-[(4-aminophenyl)ethylamine]2AgBiI8·0.5H2O, are successfully designed and synthesized by introducing chiral organic ligands into metal halide frameworks. Strikingly, the photoresponse is substantially boosted with the support of the pyro-phototronic effect, showing an increased pyro-phototronic current that is 40 times greater than the photovoltaic current. Furthermore, the pyroelectric-based detector possesses excellent CPL detection capacity to distinguish different polarization states of CPL photons, which achieve an impressive glph of up to 0.27 at zero bias. This study provides a brand new process for CPL detection by utilizing the pyro-phototronic effect in chiral-polar perovskites, which opens a new avenue for chiral materials in optoelectronic applications.

Radiation Photovoltaics in a 2D Multilayered Chiral-Polar Halide Perovskite toward Efficient Self-Driven X-Ray Detection

2D multilayered organic-inorganic hybrid perovskites (OIHPs) have exhibited bright prospects for high-performance self-driven X-ray detection due to their strong radiation absorption and long carrier transport. However, as an effective tool for self-driven X-ray detection, radiation photovoltaics remain rare, and underdeveloped in multilayered OIHPs. Herein, chirality to induce radiation photovoltaics in 2D multilayered chiral OIHPs is first utilized for efficient self-driven X-ray detection. Specifically, under X-ray irradiation, a multilayered chiral-polar (S-BPEA)2 FAPb2 I7 (1-S, S-BPEA = (S)-1-4-Bromophenylethylammonium, FA = formamidinium) shows remarkable radiation photovoltaics of 0.85 V, which endows 1-S excellent self-driven X-ray detection performance with a considerable sensitivity of 87.8 µC Gyair -1  cm-2 and a detection limit low to 161 nGyair  s-1 . Moreover, the sensitivity is high up to 1985.9 µC Gyair -1  cm-2 under 80 V bias, higher than most those of 2D OIHPs. These results demonstrate that chirality-induced radiation photovoltaics is an efficient strategy for self-driven X-ray detection.

Realization of Passive X-Ray Detection with a Low Detection Limit in Dion-Jacobson Halide Hybrid Perovskite

Halide hybrid perovskites are a kind of intriguing contenders for X-ray detection, and their low detection limits (LoDs) have played a crucial part in X-ray safety inspection and medical examination. However, there is still a significant challenge in manufacturing perovskite X-ray detectors with low LoDs. Herein, attributed to the bulk photovoltaic effect (BPVE) of a Dion-Jacobson (DJ) type 2D halide hybrid perovskite polar structure (3-methylaminopropylamine)PbBr4 (1), self-powered X-ray detection with low detection limit is successfully realized. Specifically, the crystal-based detector of 1 exhibits a low dark current at zero bias, which reduces the noise current (0.34 pA), leading to a low detection limit (58.3 nGyair s-1 ) which is two orders of magnitude lower than that of under external voltage bias. The combination of BPVE and LoDs of halide hybrid perovskite provides an efficient strategy to achieve passive X-ray detection with low doses.

Dion-Jacobson to Alternating-Cations-Interaction Reconstruction toward Narrow Bandgap 2D Aromatic Hybrid Perovskite

The 2D aromatic Dion-Jacobson (DJ) hybrid perovskites combining advantages of high stability, enhanced light absorption, and favorable charge transport, are regarded as a kind of very promising materials for high-performance optoelectronic applications. However, due to the rigidity and large size of the aromatic ring, how to further reduce the interlayer distance to achieve better carrier transport and wider light response window still remain extremely challenging. Here, an interesting DJ-to-ACI (alternating-cations-interaction) reconstruction in 2D aromatic perovskite is first realized by inserting MA+ cations into (4-AP)PbI4 (1, 4-AP = 4-amidinopyridinium), successfully constructing an unprecedented ACI perovskite of (4-AP)(MA)2 Pb2 I8 (2, MA = methylamine). Remarkably, such a DJ-to-ACI reconstruction not only effectively reduces the interlayer spacing from 3.89 to 3.15 Å but also alleviates the structural distortion, which jointly causes a significant bandgap narrowing from 2.22 to 1.95 eV (smaller than all current 2D monolayered DJ perovskites), hence achieving a broad photodetection window over 660 nm. This work reports a novel narrow bandgap 2D ACI perovskite derived from the aromatic DJ motif, which sheds light on future regulations on the structure and properties of hybrid perovskites.

Alternating chiral and achiral spacers for constructing two-dimensional chiral hybrid perovskites toward circular-polarization-sensitive photodetection

The intrinsic integration of structural flexibility, chiroptical activity, and photoelectric properties endows the two-dimensional (2D) chiral hybrid perovskites (CHPs) with significant application potential in chiroptoelectronics and spintronics. However, the scarcity of suitable chiral organic ligands severely hinders their extensive construction, necessitating the development of new strategies for designing 2D CHPs. Herein, by exploiting a half substitution method, we created a pair of 2D CHPs with alternating cations in the interlayer space (ACI), (R/S-PPA)(PA)PbBr4 (2R/2S, PPA = 1-phenylpropylamine, PA = n-pentylamine), from the achiral Ruddlesden-Popper (RP) (PA)2PbBr4 (1). The successful chirality transfer induces 2R/2S to crystallize in the chiral P212121 space group and thus acquire appealing chiroptical activity. Consequently, the single-crystal devices of 2R exhibit good distinguishability to the left- and right-handed circularly polarized 405 nm lights with a photocurrent dissymmetric factor of 0.10 at 10 V bias. This work demonstrates an intriguing achiral RP to chiral ACI motif reconstruction in 2D halide hybrid perovskites, opening a door for expanding the family of 2D CHPs.

Centimeter-Sized Single Crystals of Dion-Jacobson Phase Lead-Free Double Perovskite for Efficient X-ray Detection

2D Dion-Jacobson (DJ) phase hybrid perovskites have shown great promise in the photoelectronic field owing to their outstanding optoelectronic performance and superior structural rigidity. However, DJ phase lead-free double perovskites are still a virgin land with direct X-ray detection. Herein, we have designed and synthesized a new DJ phase lead-free layered double perovskite of (HIS)2 AgSbBr8 (1, HIS2+  = histammonium). Centimeter-sized (18 × 10 × 5 mm3 ) single crystals of 1 are successfully grown via the temperature cooling technique, exhibiting remarkable semiconductive characteristics such as a high resistivity (2.2 × 1011  Ω cm), a low trap state density (3.56 × 1010 cm-3 ), and a large mobility-lifetime product (1.72 × 10-3 cm2 V-1 ). Strikingly, its single-crystal-based X-ray detector shows a high sensitivity of 223 µC Gy-1 air cm-2 under 33.3 V mm-1 , a low detection limit (84.2 nGyair s-1 ) and superior anti-fatigue. As far as we know, we firstly demonstrates the potential of 2D DJ phase lead-free hybrid double perovskite in X-ray detection, showing excellent photoelectric response and operational stability. This work will pave a promising pathway to the innovative application of hybrid perovskites for eco-friendly and efficient X-ray detection.

Low Detection Limit Circularly Polarized Light Detection Realized by Constructing Chiral Perovskite/Si Heterostructures

Chiral perovskites have been demonstrated as promising candidates for direct circularly polarized light (CPL) detection due to their intrinsic chirality and excellent charge transport ability. However, chiral perovskite-based CPL detectors with both high distinguishability of left- and right-handed optical signals and low detection limit remain unexplored. Here, a heterostructure, (R-MPA)2 MAPb2 I7 /Si (MPA = methylphenethylamine, MA = methylammonium) is constructed, to achieve high-sensitive and low-limit CPL detection. The heterostructures with high crystalline quality and sharp interface exhibit a strong built-in electric field and a suppressed dark current, not only improving the separation and transport of the photogenerated carriers but also laying a foundation for weak CPL signals detection. Consequently, the heterostructure-based CPL detector obtains a high anisotropy factor up to 0.34 with a remarkably low CPL detection limit of 890 nW cm-2 under the self-driven mode. As a pioneering study, this work paves the way for designing high-sensitive CPL detectors that simultaneously have great distinguishing capability and low detection limit of CPL.

Unprecedented Chiral Three-dimensional Hybrid Organic-Inorganic Perovskitoids

Chiral three-dimensional hybrid organic-inorganic perovskites (3D HOIPs) would show unique chiroptoelectronic performance due to the combination of chirality and 3D structure. However, the synthesis of 3D chiral HOIPs remains a significant challenge. Herein, we constructed a pair of unprecedented 3D chiral halide perovskitoids (R/S-BPEA)EA6Pb4Cl15 (1-R/S) (R/S-BPEA=(R/S)-1-4-Bromophenylethylammonium, EA = ethylammonium), in which the large chiral cations can be contained in the big "hollow" inorganic frameworks induced by mixing cations. Notably, 3D 1-R/S shows natural chiroptical activity, as evidenced by its significant mirror circular dichroism spectra and the ability to distinguish circularly polarized light. Moreover, based on the unique 3D structure, 1-S presents sensitive X-ray detection performance with a low detection limit of 398 n Gyair s-1, which is 14 times lower than the regular medical diagnosis of 5.5 μ Gyair s-1. In this work, 3D chiral halide perovskitoids provide a new route to develop chiral material in spin electronics and photoelectronic.

Weak X-Ray to Visible Lights Detection Enabled by a 2D Multilayered Lead Iodide Perovskite with Iodine-Substituted Spacer

Broadband photodetectors (PDs) with low detection limits hold significant importance to next-generation optoelectronic devices. However, simultaneously detecting broadband (i.e., X-ray to visible regimes) and weak lights in a single semiconducting material remains highly challenging. Here, by alloying iodine-substituted short-chain cations into the 3D FAPbI₃ (FA = formamidine), a new 2D bilayered lead iodide hybrid perovskite, (2IPA)₂ FAPb₂ I₇ (1, 2IPA = 2-iodopropylammonium), that enables addressing this challenge is reported. Such a 2D multilayered structure and lead iodide composition jointly endow 1 with a minimized dark current (6.04 pA), excellent electrical property, and narrow bandgap (2.03 eV), which further gives it great potential for detecting broadband weak lights. Consequently, its high-quality single crystal PDs exhibit remarkable photoresponses to weak ultraviolet-visible lights (377-637 nm) at several tens of nW cm^-2 with high responsivities (>10²  mA W^-1 ) and significant detectivities (>10¹² Jones). Moreover, 1 has an excellent X-ray detection performance with a high sensitivity of 438 µC Gy^-1 cm^-2 and an ultralow detection limit of 20 nGy s^-1 . These exceptional attributes make 1 a promising material for broadband weak lights detection, which also sheds light on future explorations of high-performance PDs based on 2D hybrid perovskites.

Near-infrared polarization-sensitive photodetection via interfacial symmetry engineering of an Si/MAPbI3 heterostructural single crystal

Methylammonium lead iodide (MAPbI₃) single crystals (SCs) have drawn particular attention in the optoelectronics field, due to their outstanding photoelectric performance. However, the structures of those MAPbI₃ SCs are isotropic, which limits the further application of the materials for polarization-sensitive photodetection. Here, we propose a strategy of symmetry modulation by heterogeneously integrating large-sized MAPbI₃ SCs with silicon (Si) wafers and we give the first demonstration of self-powered near-infrared (NIR) polarization-sensitive photodetection using MAPbI₃ SCs. Created via a delicate solution method, the MAPbI₃/Si heterostructures show a high crystalline quality and a solid interfacial connection. More importantly, the built-in electric field resulting from the band bending at the MAPbI₃/Si heterostructure interface generates polar symmetry, which enables directional transport of photogenerated carriers, making the MAPbI₃/Si heterostructures highly polarization-sensitive. Consequently, in the self-powered mode, NIR photodetectors of MAPbI₃/Si heterostructures exhibit large polarization ratios of 3.3 at 785 nm and 2.8 at 940 nm. Moreover, a high detectivity of 7.35 × 10¹² Jones of the present devices is also achieved. Our work gives the first demonstration of self-powered polarization-sensitive photodetection of MAPbI₃ SCs and provides a strategy to design polarization-sensitive materials beyond the conventional limitations induced by isotropic structures.

[Research advances on burn blister fluid]

Burns often cause the damaged tissue to produce a large amount of exudate and the formation of blisters on the wound. The burn blister fluid contains a large number of molecules related to wound healing, which can reflect the state of local tissue microenvironment of the burn wound. Analyzing relevant information such as cellular components, signal mediators, and protein molecules in burn blister fluid is helpful to understand the local reaction and tissue microenvironment of burn wounds, and then help clinical burn treatment. In this article, by understanding the production mechanism of burn blister fluid, discussing its role in wound evaluation, and integrating the research progress of burn blister fluid in proteomics, metabolomics, cellular components, and pharmacokinetics, we propose our thoughts and prospects on the research of burn blister fluid, in order to provide assistance for clinical evaluation and treatment of burn wounds, and also provide idea for the follow-up study of burn blister fluid.

[Chaihu Guizhi Decoction plus or minus formula combined with capecitabine inhibits IL-6/STAT3 signaling to suppress triple-negative breast cancer xenografts in nude mice]

OBJECTIVE

To investigate the effect of Chaihu Guizhi Decoction (CHGZD) combined with capecitabine on growth and apoptosis of subcutaneous triple-negative breast cancer xenografts in nude mice and explore the possible mechanism.

METHODS

Nude mouse models bearing subcutaneous triple-negative breast cancer xenografts were randomized into 6 groups (n=10) for treatment with distilled water (model group), low (10.62 g/kg), medium (21.23 g/kg) and high (42.46 g/kg) doses of CHGZD, capecitabine (0.2 mg/kg), or the combination of CHGZD (42.46 g/kg) and capecitabine (0.2 mg/k) once daily for 21 consecutive days. The general condition of mice was observed, and after 21-day treatments, the tumors were dissected for measurement of tumor volume and weight and histopathological examination with HE staining. Serum IL-6 levels of the mice were determined with enzyme-linked immunosorbent assay (ELISA), and the expression levels of IL-6, STAT3, p-STAT3, Bax, Bcl-2 and cyclin D1 in the tumor tissues were detected using real-time PCR and Western blotting.

RESULTS

Compared with those in the model group, the tumor-bearing mice receiving treatments with CHGZD showed significantly increased food intake with good general condition, sensitive responses, increased body weight, and lower tumor mass (P < 0.01). Compared with capecitabine treatment alone, treatment with CHGZD alone at the medium and high doses and the combined treatment all resulted in significantly higher tumor inhibition rates (P < 0.01), induced obvious tumor tissue degeneration and reduced the tumor cell density. Treatments with CHGZD, both alone and in combination with capecitabine, significantly decreased serum IL-6 level, lowered the mRNA expression levels of IL-6 and STAT3, the protein expressions of IL-6, STAT3 and P-STAT3 (P < 0.05), and the mRNA and protein expressions of Bcl-2 and cyclin D1 (P < 0.05), and increased the mRNA and protein expressions of Bax in the tumor tissues (P < 0.05).

CONCLUSION

CHGZD combined with capecitabine can significantly inhibit tumor growth in nude mice bearing triple-negative breast cancer xenografts, the mechanism of which may involve the inhibition of IL-6/STAT3 signaling pathway and regulation of Bax, Bcl-2 and cyclin D1 expressions to suppress tumor cell proliferation and differentiation and induce cell apoptosis.

Plasma C-type lectin-like receptor 2 as a predictor of death and vascular events in patients with acute ischemic stroke

BACKGROUND AND PURPOSE

C-type lectin-like receptor 2 (CLEC-2) has prominent involvement in platelet activation, which is increased in coronary heart disease and acute ischaemic stroke (AIS) and is associated with stroke progression and stroke prognosis. Here, the aim was to examine the prognostic value of CLEC-2 in death and vascular event recurrence in AIS patients.

METHODS

In all, 352 patients with AIS were studied prospectively. All patients were followed up for 1 year. Death for all vascular events and a combination of death and vascular diseases (recurrent stroke, myocardial infarction, hospitalized and treated angina, hospitalized and treated peripheral arterial disease) were recorded.

RESULTS

During 1 year of follow-up, 46 patients (14.2%) experienced death or combined end-points (23 death and 46 combined end-points). Plasma CLEC-2 (pCLEC-2) was significantly associated with an increased risk of death and combined events of death and vascular diseases after adjusting for age, sex, history of hypertension, diabetes mellitus and coronary artery disease, and National Institutes of Health Stroke Scale scores. Each 1 SD higher log-transformed pCLEC-2 was associated with a 4.27-fold (hazard ratio 4.27, 95% confidence interval 1.71-10.65) increased risk for death and a 2.42-fold increased risk for combined end-points (hazard ratio 2.42, 95% confidence interval 1.52-3.86). The optimal cut-off point of pCLEC-2 for predicting death was 184.38 pg/ml.

CONCLUSIONS

Higher pCLEC-2 levels at admission were associated with increased risk of death and combined events of death and vascular diseases in patients with AIS, which indicated that pCLEC-2 is an important prognostic factor for AIS.

Unique Color Converter Architecture Enabling Phosphor-in-Glass (PiG) Films Suitable for High-Power and High-Luminance Laser-Driven White Lighting

As a next-generation high-power lighting technology, laser lighting has attracted great attention in high-luminance applications. However, thermally robust and highly efficient color converters suitable for high-quality laser lighting are scarce. Despite its versatility, the phosphor-in-glass (PiG) has been seldom applied in laser lighting because of its low thermal conductivity. In this work, we develop a unique architecture in which a phosphor-in-glass (PiG) film was directly sintered on a high thermally conductive sapphire substrate coated by one-dimensional photonic crystals. The designed color converter with the composite architecture exhibits a high internal quantum efficiency close to that of the original phosphor powders and an excellent packaging efficiency up to 90%. Furthermore, the PiG film can even be survived under the 11.2 W mm^-2 blue laser excitation. Combining blue laser diodes with the YAG-PiG-on-sapphire plate, a uniform white light with a high luminance of 845 Mcd m^-2(luminous flux: 1839 lm), luminous efficacy of 210 lm W^-1, and correlated color temperature of 6504 K was obtained. A high color rendering index of 74 was attained by adding a robust orange or red phosphor layer to the architecture. These outstanding properties meet the standards of vehicle regulations, enabling the PiG films with the composite architecture to be applied in automotive lighting or other high-power and high-luminance laser lighting.

Genetic analysis of a hybrid sterility gene that causes both pollen and embryo sac sterility in hybrids between Oryza sativa L. and Oryza longistaminata

Oryza longistaminata originates from African wild rice and contains valuable traits conferring tolerance to biotic and abiotic stress. However, interspecific crosses between O. longistaminata and Oryza sativa cultivars are hindered by reproductive barriers. To dissect the mechanism of interspecific hybrid sterility, we developed a near-isogenic line (NIL) using indica variety RD23 as the recipient parent and O. longistaminata as the donor parent. Both pollen and embryo sac semi-sterility were observed in F₁ hybrids between RD23 and NIL. Cytological analysis demonstrated that pollen abortion in F₁ hybrids occurred at the early bi-nucleate stage due to a failure of the first mitosis in microspores. Partial embryo sacs in the F₁ hybrids were defective during the functional megaspore formation stage. Most notably, nearly half of the male or female gametes were aborted in heterozygotes S40ⁱS40^l, regardless of their genotypes. Thus, S40 was indicated as a one-locus sporophytic sterility gene controlling both male and female fertility in hybrids between RD23 and O. longistaminata. A population of 16 802 plants derived from the hybrid RD23/NIL-S40 was developed to fine-map S40. Finally, the S40 locus was delimited to an 80-kb region on the short arm of chromosome 1 in terms with reference sequences of cv. 93-11. Eight open reading frames (ORFs) were localized in this region. On the basis of gene expression and genomic sequence analysis, ORF5 and ORF8 were identified as candidate genes for the S40 locus. These results are helpful in cloning the S40 gene and marker-assisted transferring of the corresponding neutral allele in rice breeding programs.

Abstract P5-02-05: Biology and long-term prognosis of screening detected non-palpable breast cancer by ultrasound in hospital-based Chinese population (2001-2014)

Background: Milestone studies showed that ultrasound (US) was an effective primary screening test for breast cancer both in the western world and in China [PMID: 26712110, 26715161, and 25668012]. Ultrasound has been officially designated to be the initial imaging test for breast cancer screening in Beijing and several other cities in China, due to its improved sensitivity in Chinese women who usually have denser breasts and develop breast cancer earlier than Caucasian counterparts. Study showed that it would take 40 years to screen each woman in the target age group once [PMID: 26808342].The mainstay modality of breast cancer screening in China is the hospital-based opportunistic screening among asymptomatic self-referred women. However, there is little data about the tumor biology and long-term survival of the US-detected non-palpable breast cancer (NPBC) in hospital-based Chinese population.

Methods: From January 2001 to December 2014, 3,786 asymptomatic women with positive (BI-RADS 4 and 5) initial screening US underwent biopsies in Peking Union Medical College Hospital, and 572 NPBC in 556 women were diagnosed. Women without dense breasts (defined as BI-RADS category C and D) also received screening mammography (MG) after physical examination and ultrasound. 788 patients with positive (BI-RADS 4 and 5) mammogram (MG) and normal US (BI-RADS 1, 2 and 3) underwent MG-guided biopsies and another 127 NPBC were diagnosed in 126 women. The clinicopathological features, treatment choice, 10-year disease-free survival (DFS) and overall survival (OS) were reviewed and compared between the US-detected and MG-detected NPBC. Prognostic factors of NPBC were identified.

Results: Overall, US could detect more invasive NPBC (83.4% vs 54.3%, p&lt;0.001), lymph node positive cancer (19.1% vs 10.2%, p&lt;0.001)and multifocal cancer (19.2% vs 6.3%, p&lt;0.001). In invasive NPBC, US detected more low grade cancer (21.4% vs 10.2%, p=0.001), multifocal cancer (20.7% vs 2.9%, p&lt;0.001), Her2 negative cancer (77.6% vs 62.3%, p=0.001) and larger tumor (pT1c+pT2, 53.3% vs 37.6%, p&lt;0.001). There was no significant difference in immunophenotype/subtype, treatment methods, DFS or OS between US- and MG-NPBC among ductal carcinoma in situ (DCIS), invasive and all NPBC. For all NPBC and the US-NPBC, the common DFS-factors included pT, pN and p53 whereas OS-predictors were pN and immunophenotype/subtype.

Table 1. Kaplan-Meier estimates of DFS and OS between US-NPBC and MG-NPBC§.Patients (No.)10-year DFS (%)P value10-year OS (%)P valueAllUS-NPBC (572)90.60.73896.10.142 MG-NPBC (127)92.7 100.0 DCISUS-NPBC (94)100.00.060100.0- MG-NPBC (58)93.8 100.0 InvasiveUS-NPBC (478)88.60.68095.20.239 MG-NPBC (69)92.0 100.0 § Kaplan-Meier survival curves between each two subgroups would be displayed in the poster.

Conclusion: Compared to MG, US detected more invasive NPBC with positive lymph node in hospital-based asymptomatic self-referred Chinese women, who could achieve comparable 10-year DFS and OS as MG-detected NPBC. US could serve as the feasible initial imaging modality in hospital-based opportunistic screening Chinese women.

Citation Format: Yao R, Pan B, Zhu Q, Xu Q, Zhou Y, Zhang J, Mao F, You S, Lin Y, Shi J, Guan J, Wang X, Zhang Y, Zhang X, Shen S, Zhong Y, Xu Y, Liang Z, Jiang Y, Sun Q. Biology and long-term prognosis of screening detected non-palpable breast cancer by ultrasound in hospital-based Chinese population (2001-2014) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-02-05.

Control of Immune Response to Allogeneic Embryonic Stem Cells by CD3 Antibody-Mediated Operational Tolerance Induction

Implantation of embryonic stem cells (ESCs) and their differentiated derivatives into allogeneic hosts triggers an immune response that represents a hurdle to clinical application. We established in autoimmunity and in transplantation that CD3 antibody therapy induces a state of immune tolerance. Promising results have been obtained with CD3 antibodies in the clinic. In this study, we tested whether this strategy can prolong the survival of undifferentiated ESCs and their differentiated derivatives in histoincompatible hosts. Recipients of either mouse ESC-derived embryoid bodies (EBs) or cardiac progenitors received a single short tolerogenic regimen of CD3 antibody. In immunocompetent mice, allogeneic EBs and cardiac progenitors were rejected within 20-25 days. Recipients treated with CD3 antibody showed long-term survival of implanted cardiac progenitors or EBs. In due course, EBs became teratomas, the growth of which was self-limited. Regulatory CD4(+)FoxP3(+) T cells and signaling through the PD1/PDL1 pathway played key roles in the CD3 antibody therapeutic effect. Gene profiling emphasized the importance of TGF-β and the inhibitory T cell coreceptor Tim3 to the observed effect. These results demonstrate that CD3 antibody administered alone promotes prolonged survival of allogeneic ESC derivatives and thus could prove useful for enhancing cell engraftment in the absence of chronic immunosuppression.

Evaluation of lymph node status after neoadjuvant chemotherapy in breast cancer patients: comparison of diagnostic performance of ultrasound, MRI and ¹⁸F-FDG PET/CT

Objective:

To evaluate the diagnostic performance of ultrasound, MRI and fluorine-18 fludeoxyglucose positron emission tomography (¹⁸F-FDG PET)/CT for the diagnosis of metastatic axillary lymph node (ALN) after neoadjuvant chemotherapy (NAC) and to find out histopathological factors affecting the diagnostic performance of these imaging modalities.

Methods:

From January 2012 to November 2014, 191 consecutive patients with breast cancer who underwent NAC before surgery were retrospectively reviewed. We included 139 patients with ALN metastasis that was confirmed on fine needle aspiration or core needle biopsy at initial diagnosis.

Results:

After NAC, 39 (28%) patients showed negative conversion of ALN on surgical specimens of sentinel lymph node (LN) or ALN. The sensitivity of ultrasound, MRI and PET/CT was 50% (48/96), 72% (70/97) and 22% (16/73), respectively. The specificity of ultrasound, MRI and PET/CT was 77% (30/39), 54% (21/39) and 85% (22/26), respectively. The Az value of combination of ultrasound and PET/CT was the highest (0.634) followed by ultrasound (0.626) and combination of ultrasound, MRI and PET/CT (0.617). The size of tumour deposit in LN and oestrogen receptor was significantly associated with the diagnostic performance of ultrasound (p < 0.001 and p = 0.009, respectively) and MRI (p = 0.045 and p = 0.036, respectively). The percentage diameter decrease, size of tumour deposit in LN, progesterone receptor, HER2 and histological grade were significantly associated with the diagnostic performance of PET/CT (p = 0.023, p = 0.002, p = 0.036, p = 0.044 and p = 0.008, respectively). On multivariate logistic regression analysis, size of tumour deposit within LN was identified as being independently associated with diagnostic performance of ultrasound [odds ratio, 13.07; 95% confidence interval (CI), 2.95–57.96] and PET/CT (odds ratio, 6.47; 95% CI, 1.407–29.737).

Conclusion:

Combination of three imaging modalities showed the highest sensitivity, and PET/CT showed the highest specificity for the evaluation of ALN metastasis after NAC. Ultrasound alone or combination of ultrasound and PET/CT showed the highest positive-predictive value. The size of tumour deposit within ALN was significantly associated with diagnostic performance of ultrasound and PET/CT.

Advances in knowledge:

This study is about the diagnostic performance of ultrasound, MRI, PET/CT and combination of each imaging modality for the evaluation of metastatic ALN after NAC. Of many histopathological factors, only the size of tumour deposit within ALN was an independent factor associated with the diagnostic performance of ultrasound and PET/CT.

Analysis of underlying causes of inter-expert disagreement in retinopathy of prematurity diagnosis. Application of machine learning principles

OBJECTIVE

Inter-expert variability in image-based clinical diagnosis has been demonstrated in many diseases including retinopathy of prematurity (ROP), which is a disease affecting low birth weight infants and is a major cause of childhood blindness. In order to better understand the underlying causes of variability among experts, we propose a method to quantify the variability of expert decisions and analyze the relationship between expert diagnoses and features computed from the images. Identification of these features is relevant for development of computer-based decision support systems and educational systems in ROP, and these methods may be applicable to other diseases where inter-expert variability is observed.

METHODS

The experiments were carried out on a dataset of 34 retinal images, each with diagnoses provided independently by 22 experts. Analysis was performed using concepts of Mutual Information (MI) and Kernel Density Estimation. A large set of structural features (a total of 66) were extracted from retinal images. Feature selection was utilized to identify the most important features that correlated to actual clinical decisions by the 22 study experts. The best three features for each observer were selected by an exhaustive search on all possible feature subsets and considering joint MI as a relevance criterion. We also compared our results with the results of Cohen's Kappa [36] as an inter-rater reliability measure.

RESULTS

The results demonstrate that a group of observers (17 among 22) decide consistently with each other. Mean and second central moment of arteriolar tortuosity is among the reasons of disagreement between this group and the rest of the observers, meaning that the group of experts consider amount of tortuosity as well as the variation of tortuosity in the image.

CONCLUSION

Given a set of image-based features, the proposed analysis method can identify critical image-based features that lead to expert agreement and disagreement in diagnosis of ROP. Although tree-based features and various statistics such as central moment are not popular in the literature, our results suggest that they are important for diagnosis.

Reduced expression of regeneration associated genes in chronically axotomized facial motoneurons

Chronically axotomized motoneurons progressively fail to regenerate their axons. Since axonal regeneration is associated with the increased expression of tubulin, actin and GAP-43, we examined whether the regenerative failure is due to failure of chronically axotomized motoneurons to express and sustain the expression of these regeneration associated genes (RAGs). Chronically axotomized facial motoneurons were subjected to a second axotomy to mimic the clinical surgical procedure of refreshing the proximal nerve stump prior to nerve repair. Expression of α1-tubulin, actin and GAP-43 was analyzed in axotomized motoneurons using in situ hybridization followed by autoradiography and silver grain quantification. The expression of these RAGs by acutely axotomized motoneurons declined over several months. The chronically injured motoneurons responded to a refreshment axotomy with a re-increase in RAG expression. However, this response to a refreshment axotomy of chronically injured facial motoneurons was less than that seen in acutely axotomized facial motoneurons. These data demonstrate that the neuronal RAG expression can be induced by injury-related signals and does not require acute deprivation of target derived factors. The transient expression is consistent with a transient inflammatory response to the injury. We conclude that transient RAG expression in chronically axotomized motoneurons and the weak response of the chronically axotomized motoneurons to a refreshment axotomy provides a plausible explanation for the progressive decline in regenerative capacity of chronically axotomized motoneurons.

Melanocyte-specific CD8+ T cells are associated with epidermal depigmentation in a novel mouse model of vitiligo

In the present study, we established a novel murine model of vitiligo by sequential prime/boost immunizations into the hind footpad and tail dermis with tyrosinase-related protein 2 (TRP2)-180 (SVYDFFVWL) peptide, lipopolysaccharides and cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides. Immunized mice developed epidermal depigmentation in the tail skin without hair depigmentation, thereby differentiating this approach from established models of vitiligo. Following intradermal tail immunization, activated CD8(+) interferon (IFN)-γ(+) T cells were recruited locally to the tail skin. In-vivo cytotoxicity assays demonstrated specific lysis of TRP2-180-presenting cells in immunized mice. Furthermore, the extent of skin depigmentation correlated with the frequency of TRP2-180-specific splenic CD8(+) T cells, as determined by IFN-γ and tumour necrosis factor (TNF)-α production, and cytotoxic degranulation evidenced by CD107a staining. These findings suggest a correlation between the presence of TRP2-180-specific CD8(+) effector T cells and the development of depigmented skin lesions in our vitiligo model. This new model of vitiligo, characterized by skin depigmentation without hair depigmentation, is more similar to human disease than previous murine models. Therefore, this model is well suited to future studies on the pathogenesis of vitiligo and the development of novel therapeutics for vitiligo.

Delayed anti-CD3 therapy results in depletion of alloreactive T cells and the dominance of Foxp3+ CD4+ graft infiltrating cells

The engineered Fc-nonbinding (crystallizable fragment-nonbinding) CD3 antibody has lower mitogenicity and a precise therapeutic window for disease remission in patients with type 1 diabetes. Before anti-CD3 can be considered for use in transplantation, the most effective timing of treatment relative to transplantation needs to be elucidated. In this study anti-CD3F(ab')2 fragments or saline were administered intravenously for 5 consecutive days (early: d1-3 or delayed: d3-7) to mice transplanted with a cardiac allograft (H2(b)-to-H2(k); d0). Survival of allografts was prolonged in mice treated with the early protocol (MST = 48 days), but most were rejected by d100. In contrast, in mice treated with the delayed protocol allografts continued to survive long term. The delayed protocol significantly inhibited donor alloreactivity at d30 as compared to the early protocol. A marked increase in Foxp3(+) T cells (50.3 ± 1.6%) infiltrating the allografts in mice treated with the delayed protocol was observed (p < 0.0001 vs. early (24.9 ± 2.1%)) at d10; a finding that was maintained in the accepted cardiac allografts at d100. We conclude that the timing of treatment with anti-CD3 therapy is critical for inducing long-term graft survival. Delaying administration effectively inhibits the alloreactivity and promotes the dominance of intragraft Foxp3(+) T cells allowing long-term graft acceptance.

Induction of allograft tolerance by monoclonal CD3 antibodies: a matter of timing

Despite remarkable progress in organ transplantation through the development of a wealth of immunosuppressive drugs highly effective at controlling acute rejection, two major problems still remain, the loss of transplants due to chronic rejection and the growing number of sensitized recipients due to previous transplants, transfusions or pregnancies. Induction of immune tolerance appears to be the only way to curb this complex situation. Here we describe that a therapy, already successfully used to restore immune tolerance to self-antigens in overt autoimmunity, is effective at promoting transplant tolerance. We demonstrate that a short low-dose course with CD3 antibodies started after transplantation, at the time of effector T cell priming to alloantigens, induces permanent acceptance of fully mismatched islet allografts. Mechanistic studies revealed that antigen-specific regulatory and effector T cells are differentially affected by the treatment. CD3 antibody treatment preferentially induces apoptosis of activated alloreactive T cells which is mandatory for tolerance induction. In contrast, regulatory T cells are relatively spared from CD3 antibody-induced depletion and can transfer antigen-specific tolerance thus arguing for their prominent role in sustaining long-term graft survival.

OBSERVER AND FEATURE ANALYSIS ON DIAGNOSIS OF RETINOPATHY OF PREMATURITY

Retinopathy of prematurity (ROP) is a disease affecting low-birth weight infants and is a major cause of childhood blindness. However, human diagnoses is often subjective and qualitative. We propose a method to analyze the variability of expert decisions and the relationship between the expert diagnoses and features. The analysis is based on Mutual Information and Kernel Density Estimation on features. The experiments are carried out on a dataset of 34 retinal images diagnosed by 22 experts. The results show that a group of observers decide consistently with each other and there are popular features that have a high correlation with labels.

Principal curve based semi-automatic segmentation of organs in 3D-CT

Radiation therapy plays an important and effective role in the treatment of cancer. A main goal in radiation therapy is to deliver high radiation doses to the perceived tumors while minimizing radiation to surrounding normal tissues. Manual delineation of tumors and organs-at-risk(OARs) on three-dimensional computed tomography (3D-CT) is both a time-consuming and labor intensive task, and there maybe variability between manual delineations by different radiation oncologists. In this paper, we present a semi-supervised method to segment the contours of organs represented by piecewise linear segments connected with a small number of points given the user's input in one or more slices as an approximate initialization. This method detects ridge samples from the kernel interpolation of the edge map and approximates the shape of organs using piecewise linear segments among those sample points based on the principal curve score. Results are provided in two 3D-CT scans. Evaluation of the efficacy of our semiautomatic segmentation method is based on the overlapping ratio between the manually delineated contours and the semiautomatic segmented contours represented by a small number of points. The preserved points can be as low as 10 percent of the initial manual points, and the Dice Coefficients are approximately 0.93 for lung segmentation.