Dual-Stimuli-Responsive Modulation Organic Afterglow Based on N─H Proton Migration Mechanism.

Organic afterglow materials have significant applications in information security and flexible electronic devices with unique optical properties. It is vital but challenging to develop organic afterglow materials possessing controlled output with multi-stimuli-responsive capacity. Herein, dimethyl terephthalate (DTT) is introduced as a strong proton acceptor. The migration direction of N─H protons on two compounds Hs can be regulated by altering the excitation wavelength (Ex) or amine stimulation, thereby achieving dual-stimuli-responsive afterglow emission. When the Ex is below 300 nm, protons migrate to S1-2 DTT, where strong interactions induce phosphorescent emission of Hs, resulting in afterglow behavior. Conversely, when the Ex is above 300 nm, protons interact with the S0 DTT weakly and the afterglow disappears. In view of amine-based compounds with higher proton accepting capabilities, it can snatch proton from S1-2 DTT and redirect the proton flow toward amine, effectively suppressing the afterglow but obtaining a new redshifted fluorescence emission with Δλ over 200 nm due to the high polarity of amine. Moreover, it is successfully demonstrated that the applications of dual-stimuli-responsive organic afterglow materials in information encryption based on the systematic excitation-wavelength-dependent (Ex-De) behavior and amine selectivity detection.

Enhanced performance of quantum dot light-emitting diodes enabled by zirconium doped SnO2 as electron transport layers.

Next-generation display and lighting based on quantum dot light-emitting diodes (QLEDs) require a balanced electron injection of electron transport layers (ETLs). However, classical ZnO nanoparticles (NPs) as ETLs face inherent defects such as excessive electron injection and positive aging effects, urgently requiring the development of new types of ETL materials. Here, we show that high stability SnO2 NPs as ETL can significantly improve the QLED performance to 100567 cd·m-2 luminance, 14.3% maximum external quantum efficiency, and 13.1 cd·A-1 maximum current efficiency using traditional device structures after optimizing the film thickness and annealing the temperature. Furthermore, experimental tests reveal that by doping Zr4+ ions, the size of SnO2 NPs will reduce, dispersion will improve, and energy level will shift up. As expected, when using Zr-SnO2 NPs as the ETL, the maximum external quantum efficiency can reach 16.6%, which is close to the state-of-the-art QLEDs based on ZnO ETL. This work opens the door for developing novel, to the best of our knowledge, type ETLs for QLEDs.

Boosting Cu─In─Zn─S-based Quantum-Dot Light-Emitting Diodes Enabled by Engineering Cu─NiOx /PEDOT:PSS Bilayered Hole-Injection Layer.

The imbalance of charge injection is considered to be a major factor that limits the device performance of cadmium-free quantum-dot light-emitting diodes (QLEDs). In this work, high-performance cadmium-free Cu─In─Zn─S(CIZS)-based QLEDs are designed and fabricated through tailoring interfacial energy level alignment and improving the balance of charge injection. This is achieved by introducing a bilayered hole-injection layer (HIL) of Cu-doped NiOx (Cu─NiOx )/Poly(3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS). High-quality Cu─NiOx film is prepared through a novel and straightforward sol-gel procedure. Multiple experimental characterizations and theoretical calculations show that the incorporation of Cu2+ ions can regulate the energy level structure of NiOx and enhance the hole mobility. The state-of-art CIZS-based QLEDs with Cu─NiOx /PEDOT:PSS bilayered HIL exhibit the maximum external quantum efficiency of 6.04% and half-life time of 48 min, which is 1.3 times and four times of the device with only PEDOT:PSS HIL. The work provides a new pathway for developing high-performance cadmium-free QLEDs.

Electroluminescent white light-emitting diodes with cadimum-free Cu-In-Zn-S nanocrystals sandwiched between two TFB layers.

A high color rendering index (CRI) and stable spectra under different voltages are important parameters for large-area planar light sources. However, the spectrum of most electroluminescent white light-emitting diodes (el-WLEDs) with a single emissive layer (EML) varies with a changing voltage. Herein, an el-WLED is fabricated based on Cd-free Cu-In-Zn-S (CIZS)/ZnS nanocrystals (NCs) and poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB) as double EMLs, which exhibit white-light emission with a high CRI value of 91 and commission internationale de l'éclairage (CIE) color coordinates of (0.33, 0.33). Meanwhile, it has a stable spectrum under voltage up to 7 V and a maximum luminance up to 679 cd/m2 with a low turn-on voltage of 2.2 V. This work provides a foundation for Cd-free el-WLEDs with high CRI and stable spectra.

Synthesis of Lead-Free Cs2AgBiX6 (X = Cl, Br, I) Double Perovskite Nanoplatelets and Their Application in CO2 Photocatalytic Reduction.

Morphology control represents an important strategy for the development of functional nanomaterials and has yet to be achieved in the case of promising lead-free double perovskite materials so far. In this work, high-quality Cs2AgBiX6 (X = Cl, Br, I) two-dimensional nanoplatelets were synthesized through a newly developed synthetic procedure. By analyzing the optical, morphological, and structural evolutions of the samples during synthesis, we elucidated that the growth mechanism of lead-free double perovskite nanoplatelets followed a lateral growth process from mono-octahedral-layer (half-unit-cell in thickness) cluster-based nanosheets to multilayer (three to four unit cells in thickness) nanoplatelets. Furthermore, we demonstrated that Cs2AgBiBr6 nanoplatelets possess a better performance in photocatalytic CO2 reduction compared with their nanocube counterpart. Our work demonstrates the first example with two-dimensional morphology of this important class of lead-free perovskite materials, shedding light on the synthetic manipulation and the application integration of such promising materials.

Solution-processed double-layered hole transport layers for highly-efficient cadmium-free quantum-dot light-emitting diodes.

The search for heavy-metal-free quantum-dot light-emitting diodes (QD-LEDs) has greatly intensified in the past few years because device performance still falls behind that of CdSe-based QD-LEDs. Apart from the effects of nanostructures of the emitting materials, the unbalanced charge injection and transport severely affects the performance of heavy-metal-free QD-LEDs. In this work, we presented solution-processed double hole transport layers (HTLs) for improving the device performance of heavy-metal-free Cu-In-Zn-S(CIZS)/ZnS-based QD-LEDs, in which N,N'-Bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (TPD) as an interlayer was incorporated between the emitting layer and the HTL. Through optimizing the thickness of poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenyl-amine (TFB) and TPD layers, a maximum external quantum efficiency (ηEQE) of 3.87% and a current efficiency of 9.20 cd A-1 were achieved in the solution-processed QD-LEDs with double-layered TFB/TPD as the HTLs, which were higher than those of the devices with pristine TFB, TPD and TFB:TPD blended layers. The performance enhancement could be attributed to the synergistic effects of the reduction of the hole injection barrier, the increase of the hole mobility and suppressed charge transfer between the HTL and the emitting layer. Furthermore, the best ηEQE of 5.61% with a mean ηEQE of 4.44 ± 0.73% was realized in the Cu-In-Zn-S-based QD-LEDs by varying the annealing temperature of TPD layer due to the more balanced charge injection and transport as well as smooth surface of TPD layer.

Seed-Mediated Growth of Anatase TiO2 Nanocrystals with Core-Antenna Structures for Enhanced Photocatalytic Activity.

We demonstrate that anatase TiO2 nanocrystals composed of a nanocrystal core and nanorod antennas can be produced via a nonaqueous colloidal seed-mediated growth method. Anatase TiO2 nanocrystals with defined morphologies were first prepared as seeds, and then secondary anatase TiO2 nanorods were grown on the defined facets of the seeds under appropriate conditions. Systematic studies on the growth mechanism reveal that the formation of core-antenna nanocrystals involves an epitaxial growth process with specific orientational preference governed by both thermodynamic and kinetic factors. By manipulating the reaction conditions including the precursor amount and introduction rate, the epitaxial growth behavior can be well controlled. By further varying the morphology of seed nanocrystals, we have also been able to produce core-antenna anatase TiO2 nanocrystals with complex spatial configurations in a highly predictable manner. The high structural configurability and predictability offered by this seed-mediated growth method may provide great opportunities in enhancing the performance of TiO2-based nanostructures in many energy-related applications. As a demonstration, we show by simply manipulating the core-antenna structures that the photocatalytic activity of the anatase nanocrystals can be improved from the relatively less active seed nanocrystals or pure nanorods to the extent that exceeds the activity of the commercial P25 titania.

Highly Efficient Flexible Photodetectors Based on Pb-Free CsBi3I10 Perovskites.

Perovskites have made remarkable advancements in optoelectronics owing to their high light absorption coefficient, tunable bandgap, and long charge diffusion. Nonetheless, the practical applications of Pb-based perovskites have been hindered by the instability and toxicity of Pb, especially in flexible electronics, which require high biosecurity and low toxicity. Hence, the development of stable Pb-free perovskite materials has gained increasing attention. In this study, we synthesized stable CsBi3I10 Pb-free perovskites outside the glovebox and improved the optoelectronic and mechanical performances of the CsBi3I10-based flexible devices through polyvinylcarbazole (PVK) doping. Flexible photodetectors with the device structure of PET/ITO/PEDOT:PSS/CsBi3I10:PVK/Au was fabricated. The results indicated that the introduction of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) reduced the surface roughness of the flexible PET substrate, while PVK doping further improved the surface smoothness of CsBi3I10 thin films, thereby enhancing the interfacial charge transportation. Moreover, PEDOT:PSS and PVK acted as stepwise hole transport layers in the photodetectors. The device demonstrated a maximum responsivity of 0.3 A/W, detectivity of 2.6 × 1011 Jones, and a response time of 102 µs at 650 nm. After subjecting it to 1000 bending tests, the light current retained 80% of its initial value. This study presents a universally applicable method for controlling the surface morphology of a flexible perovskite thin film.

Seed-mediated growth synthesis and tunable narrow-band luminescence of quaternary Ag-In-Ga-S alloyed nanocrystals.

Silver-based I-III-VI-type semiconductor nanocrystals have received extensive attention due to their narrow-band luminescence properties. Herein, we demonstrated a seed-mediated growth of quaternary Ag-In-Ga-S (AIGS) nanocrystals (NCs) with narrow-band luminescence. By conducting partial cation exchange with In3+ and Ga3+ based on Ag2S NCs and controlling the Ag/In feeding ratios (0.25 to 2) of Ag-In-S seeds as well as the inventory of 1-dodecanethiol, we achieved optimized luminescence performance in the synthesized AIGS NCs, characterized by a narrow full width at half maximum of less than 40 nm. Meanwhile, narrow-band luminescent AIGS NCs exhibit a tetragonal AgGaS2 crystal structure and a gradient alloy structure, rather than a core-shell structure. Most importantly, the kinetics decay curves of time-resolved photoluminescence and the ground state bleaching in transient absorption generally agree with each other regarding the lifetime of the second decay component, which indicates that the narrow-band luminescence is due to the slow radiative recombination between trapped electrons and trapped holes located at the edge of the conduction band and the deep silver-related trap states (e.g., silver vacancy), respectively. This study provides new insights into the correlation between the narrow-band luminescence properties and the structural characteristics of AIGS NCs.

Multiparticle Synergistic Electrophoretic Deposition Strategy for High-Efficiency and High-Resolution Displays.

Colloidal nanoparticles offer unique photoelectric properties, making them promising for functional applications. Multiparticle systems exhibit synergistic effects on the functional properties of their individual components. However, precisely controlled assembly of multiparticles to form patterned building blocks for solid-state devices remains challenging. Here, we demonstrate a versatile multiparticle synergistic electrophoretic deposition (EPD) strategy to achieve controlled assembly, high-efficiency, and high-resolution patterns. Through elaborate surface design and charge regulation of nanoparticles, we achieve precise control over the particle distribution (gradient or homogeneous structure) in multiparticle films using the EPD technique. The multiparticle system integrates silicon oxide and titanium oxide nanoparticles, synergistically enhancing the emission efficiency of quantum dots to a high level in the field. Furthermore, we demonstrate the superiority of our strategy to integrate multiparticle into large-area full-color display panels with a high resolution over 1000 pixels per inch. The results suggest great potential for developing multiparticle systems and expanding diverse functional applications.

A feasibility trial of screening women with idiopathic recurrent miscarriage for high uterine natural killer cell density and randomizing to prednisolone or placebo when pregnant.

STUDY QUESTION: Is it feasible to screen women with idiopathic recurrent miscarriage (RM) for high uterine natural killer (uNK) cell density and then randomize them to prednisolone or placebo when pregnant? SUMMARY ANSWER: It was feasible to recruit women with idiopathic RM into a 'screen and treat' trial despite their desire for active medication. WHAT IS KNOWN ALREADY: Clinical trials of immunotherapy in women with idiopathic RM have failed to substantiate efficacy in preventing miscarriage. Preimplantation uNK cell density is higher in women with RM and can be reduced with prednisolone. STUDY DESIGN, SIZE, DURATION: In a pilot RCT, 160 eligible women were screened with an endometrial biopsy and those with high uNK cell density were invited to return when pregnant for randomization to prednisolone (20 mg for 6 weeks, 10 mg for 1 week, 5 mg for 1 week) or identical placebo tablets. Randomization was by random number generation and patients, clinicians and outcome assessors were blinded to allocation. The study size and duration was determined by funding, which was for a feasibility trial, for 2 years, sufficient to screen 150 women and randomize 40 women. The outcome measures were recruitment rate, women's perspectives, compliance, live birth and miscarriage rates and pregnancy complications. PARTICIPANTS/MATERIALS, SETTING, METHODS: The trial was advertised nationally in the UK. Women who attended research clinics run by one consultant (SQ) with three or more consecutive idiopathic miscarriages were included. Women's perspectives of the trial were sought through a questionnaire. The endometrium was sampled 5-9 days after the LH surge, stained using immunohistochemistry for CD56 and the sub-epithelial region analysed with image analysis. Women with a high uNK cell density (>5%) were invited to contact the clinic at 4-6 weeks gestation for randomization. Compliance with medication was assessed using a daily log, and side effects recorded by the women in a diary and on a structured proforma completed in the clinic at the end of the first trimester. All women had ultrasound scans every 2 weeks until 14 weeks' gestation and growth scans at 28 and 34 weeks' gestation in addition to routine antenatal care and a follow-up in person or by telephone 6 weeks after delivery. MAIN RESULTS AND THE ROLE OF CHANCE: Despite the fact that 85% of women said they would prefer the active treatment, the trial recruitment occurred at the planned rate. Eligible women (n = 160) attended the research clinics and had the uNK test, 72 were screen positive and 40 returned when pregnant for randomization. Compliance with medication was reported to be 100%. The active treatment was associated with side effects of insomnia and flushing. The live birth rate was 12/20 (60%) with prednisolone and 8/20 (40%) with placebo (Risk Ratio 1.5, 95% confidence interval (CI) 0.79-2.86, absolute difference 20% CI-10%, +50%), and hence, this was not significant. There were no pregnancy complications or serious adverse fetal outcomes. LIMITATIONS, REASONS FOR CAUTION: This was a feasibility trial so of insufficient size to assess efficacy or safety. There was inconsistency in the start date of the trial medication and this may have affected the outcome in the active treatment group. WIDER IMPLICATIONS OF THE FINDINGS: It was feasible to recruit women with idiopathic RM into a 'screen and treat' trial despite their desire for active medication. Our data also suggest that in future trials the primary outcome measure is live birth rate after 24 weeks gestation.

Organic ultraviolet photodetector based on phosphorescent material.

A new type of organic visible-blind UV-PDs is demonstrated by utilizing phosphorescent material Ir(III)bis[(4,6-difluorophenyl)-pyridinato-N, C(2)'] picolinate (FIrpic) as the electron donor and [6,6]-phenyl-C-61-butyricacidmethylester (PCBM) as the electron accepter, respectively. The peak responsivity of the organic UV-PDs is as high as 140 mA/W, corresponding to an external quantum efficiency of about 48%, under 365 nm UV light with an intensity of 0.018 mW/cm(2). The distinct photoluminescence quenching of FIrpic is obtained by doping PCBM. The organic UV-PDs provide visible-blind performance with the strong photocurrent response in the UV-A region, the rise and fall times of less than one second, and linear response within the incident light-intensity range from 0.018 to 20 mW/cm(2).

Facile one-step synthesis and transformation of Cu(I)-doped zinc sulfide nanocrystals to Cu(1.94)S-ZnS heterostructured nanocrystals.

A facile one-pot heating process without any injection has been developed to synthesize different Cu-Zn-S-based nanocrystals. The composition of the products evolves from Cu(I)-doped ZnS (ZnS:Cu(I)) nanocrystals into heterostructured nanocrystals consisting of monoclinic Cu1.94S and wurtzite ZnS just by controlling the molar ratios of zinc acetylacetonate (Zn(acac)2) to copper acetylacetonate (Cu(acac)2) in the mixture of n-dodecanethiol (DDT) and 1-octadecene (ODE). Accompanying the composition transformation, the crystal phase of ZnS is changed from cubic zinc blende to hexagonal wurtzite. Depending on the synthetic parameters including the reaction time, temperature, and the feeding ratios of Zn/Cu precursors, the morphology of the as-obtained heterostructured nanocrystals can be controlled in the forms of taper-like, matchstick-like, tadpole-like, or rod-like. Interestingly, when the molar ratio of Cu(acac)2 to Zn(acac)2 is increased to 9:1, the crystal phase of the products is transformed from monoclinic Cu1.94S to the mixed phase composed of cubic Cu1.8S and tetragonal Cu1.81S as the reaction time is further prolonged. The crystal-phase transformation results in the morphological change from quasi-spherical to rice shape due to the incorporation of Zn ions into the Cu1.94S matrix. This method provides a simple but highly reproducible approach for synthesis of Cu(I)-doped nanocrystals and heterostructured nanocrystals, which are potentially useful in the fabrication of optoelectronic devices.

Controllable synthesis of silver and silver sulfide nanocrystals via selective cleavage of chemical bonds.

A one-step colloidal process has been adopted to prepare silver (Ag) and silver sulfide (Ag2S) nanocrystals, thus avoiding presynthesis of an organometallic precursor and the injection of a toxic phosphine agent. During the reaction, a layered intermediate compound is first formed, which then acts as a precursor, decomposing into the nanocrystals. The composition of the as-obtained products can be controlled by selective cleavage of S-C bonds or Ag-S bonds. Pure Ag2S nanocrystals can be obtained by directly heating silver acetate (Ag(OAc)) and n-dodecanethiol (DDT) at 200 ° C without any surfactant, and pure Ag nanocrystals can be synthesized successfully if the reaction temperature is reduced to 190 ° C and the amount of DDT is decreased to 1 ml in the presence of a non-coordinating organic solvent (1-octadecene, ODE). Otherwise, the mixture of Ag and Ag2S is obtained by directly heating Ag(OAc) in DDT by increasing the reaction temperature or in a mixture of DDT and ODE at 200 ° C. The formation mechanism has been discussed in detail in terms of selective S-C and Ag-S bond dissociation due to the nucleophilic attack of DDT and the lower bonding energy of Ag-S. Interestingly, some products can easily self-assemble into two- or three-dimensional (2D or 3D) highly ordered superlattice structures on a copper grid without any additional steps. The excess DDT plays a key role in the superlattice structure due to the bundling and interdigitation of the thiolate molecules adsorbed on the as-obtained nanocrystals.

Vitamin B12 deficiency presenting with a pancytopenia in pregnancy.

Vitamin B12 deficiency is a significant public health problem globally. Although it is a well-known cause of macrocytic anaemia and in advanced cases, pancytopenia, there remains a relative paucity of cases reported in pregnancy. It is associated with an increased risk of pregnancy complications and adverse birth outcomes such as neural tube defects, preterm birth, low birth weight, neurological sequelae and intrauterine death. It has a predilection for individuals aged >60 years. It has been implicated in a spectrum of neuropsychiatric disorders and it may also exert indirect cardiovascular effects. Severe vitamin B12 deficiency may present with haematological abnormalities that mimic thrombotic microangiopathy such as HELLP syndrome (haemolysis, elevated liver enzymes and low platelets) or it may present as pseudothrombotic microangiopathy (Moschcowitz syndrome) characterised by anaemia, thrombocytopenia and schistocytosis. It can also closely mimic thrombotic thrombocytopenia purpura, hence posing a diagnostic challenge to the unwary physician. Serological measurement of vitamin B12 levels confirms the diagnosis. Oral supplementation with vitamin B12 remains a safe and effective treatment. The authors describe the case of a multiparous woman in her late 20s presenting with a plethora of non-specific symptoms at 29+5 weeks' gestation. Her haemoglobin was 45 g/L, platelets 32×109/L, vitamin B12 <150 ng/L and serum folate <2 µg/L. She was not a vegetarian, but her diet lacked nutrition. Following parenteral B12 supplementation, her haematological parameters improved. The pregnancy was carried to term. Due to the plethora of non-specific symptoms, the diagnosis can be challenging to establish. Adverse maternal or fetal outcomes may occur. Folic acid supplementation may mask an occult vitamin B12 deficiency and further exacerbate or initiate neurological disease.

The Scale Effects of Organometal Halide Perovskites.

Organometal halide perovskites have achieved great success in solution-processed photovoltaics. The explorations quickly expanded into other optoelectronic applications, including light-emitting diodes, lasers, and photodetectors. An in-depth analysis of the special scale effects is essential to understand the working mechanisms of devices and optimize the materials towards an enhanced performance. Generally speaking, organometal halide perovskites can be classified in two ways. By controlling the morphological dimensionality, 2D perovskite nanoplatelets, 1D perovskite nanowires, and 0D perovskite quantum dots have been studied. Using appropriate organic and inorganic components, low-dimensional organic-inorganic metal halide hybrids with 2D, quasi-2D, 1D, and 0D structures at the molecular level have been developed and studied. This provides opportunities to investigate the scale-dependent properties. Here, we present the progress on the characteristics of scale effects in organometal halide perovskites in these two classifications, with a focus on carrier diffusion, excitonic features, and defect properties.

Two-Dimensional Cs2 AgInx Bi1- x Cl6 Alloyed Double Perovskite Nanoplatelets for Solution-Processed Light-Emitting Diodes.

Lead-free double perovskites have emerged as a promising class of materials with potential to be integrated into a wide range of optical and optoelectronic applications. Herein, the first synthesis of 2D Cs2 AgInx Bi1- x Cl6 (0 ≤ x ≤ 1) alloyed double perovskite nanoplatelets (NPLs) with well controlled morphology and composition is demonstrated. The obtained NPLs show unique optical properties with the highest photoluminescence quantum yield of 40.1%. Both temperature dependent spectroscopic studies and density functional theory calculation results reveal that the morphological dimension reduction and In-Bi alloying effect together boost the radiative pathway of the self-trapped excitons of the alloyed double perovskite NPLs. Moreover, the NPLs exhibit good stability under ambient conditions and against polar solvents, which is ideal for all solution-processing of the materials in low-cost device manufacturing. The first solution-processed light-emitting diodes is demonstrated using the Cs2 AgIn0.9 Bi0.1 Cl6 alloyed double perovskite NPLs as the sole emitting component, showing luminance maximum of 58 cd m-2 and peak current efficiency of 0.013 cd A-1 . This study sheds light on morphological control and composition-property relationships of double perovskite nanocrystals, paving the way toward ultimate utilizations of lead-free perovskite materials in diverse sets of real-life applications.

Subsite-specific metastatic organotropism and risk in gastric cancer: A population-based cohort study of the US SEER database and a Chinese single-institutional registry.

BACKGROUND: Studies exploring whether metastatic organotropism and risk in gastric cancer (GC) differ by primary anatomical site are scarce. METHODS: This study included 15,260 and 1623 patients diagnosed with GC from the Surveillance, Epidemiology, and End Results (SEER) registry database and the Nanfang Hospital in China, respectively. Patients were stratified according to primary site of GC, and the incidence of metastasis to different organs was used to determine the metastatic organotropism for each GC subsite. Finally, the metastatic organotropism and risk were compared among the different subsite groups. RESULTS: Liver metastasis was the most common metastasis site in cardia GC, whereas other-site metastases were more common in the body, antrum, overlapping lesions, and unspecified GCs. Liver and other-site metastases were also frequently observed in the fundus, pylorus, lesser curvature, and greater curvature GCs. Patients with GC with definite primary tumor sites in the SEER and validation Nanfang hospital cohorts were compared by grouping as proximal and distal GCs for further analysis. In the SEER cohort, the top three metastatic sites of proximal GC were liver (21.4%), distant lymph node (LN) (14.6%), and other-site (mainly peritoneum, 11.9%), whereas those of distal GC were other-site (mainly peritoneum, 19.5%), liver (11.8%), and distant LN (9.5%). The incidence of metastasis to the liver, distant LN, lung, and brain was significantly higher in patients with proximal GC than in those with distal GC in both the SEER and Nanfang cohorts (p < 0.05). However, metastasis to other-site/peritoneum was significantly lower in patients with proximal GC compared to those with distal GC in the Nanfang Hospital and SEER cohorts, respectively (p < 0.05). CONCLUSION: Liver and distant LN are the preferred metastatic sites for proximal GC, whereas peritoneal metastasis is more common in distal GC. Proximal GC has a higher risk of lymphatic and hematogenous metastases, and a lower risk of transcoelomic metastasis than distal GC. Our findings highlight the need to stratify GC by its primary subsite to aid in planning and decision-making related to metastatic management in clinical practice.

Shape-controlled synthesis of PbS nanocrystals via a simple one-step process.

A one-step colloidal process was adopted to prepare face-centered-cubic PbS nanocrystals with different shapes such as octahedral, starlike, cubic, truncated octahedral, and truncated cubic. The features of this approach avoid the presynthesis of any organometallic precursor and the injection of a toxic phosphine agent. A layered intermediate compound (lead thiolate) forms in the initial stage of the reaction, which effectively acts as the precursor to decompose into the PbS nanocrystals. The size and shape of the PbS nanocrystals can be easily controlled by varying the reaction time, the reactant concentrations, the reaction temperatures, and the amount of surfactants. In particular, additional surfactants other than dodecanethiol, such as oleylamine, oleic acid, and octadecene, play an important role in the shape control of the products. The possible formation mechanism for the PbS nanocrystals with various shapes is presented on the basis of the different growth directions of the nanocrystals with the assistance of the different surfactants. This method provides a facile, low-cost, highly reproducible process for the synthesis of PbS nanocrystals that may have potential applications in the fabrication of photovoltaic devices and photodetectors.

Unraveling the Phase Transition and Luminescence Tuning of Pb-Free Cs-Cu-I Perovskites Enabled by Reaction Temperature and Polar Solvent.

Ternary Pb-free Cs-Cu-I perovskites have attracted widespread attention because of their excellent optical properties and environmentally friendly advantages. Herein, two different Pb-free ternary Cs3Cu2I5 nanocrystals (NCs) and CsCu2I3 microrods (MRs) were synthesized via a heating method. The phase and morphology transition from blue emission of Cs3Cu2I5 NCs to yellow emission of CsCu2I3 MRs could be tuned effectively by manipulating the reaction temperature, decreasing the maximum photoluminescence quantum yields (PLQYs) from 82.7% to ∼10%. More interestingly, the Cs3Cu2I5 NCs could self-assemble into stacking chains, which exhibited a strong dependence on the polarity of solvents. In addition, it was demonstrated that the rapid phase transition and luminescence tuning between Cs3Cu2I5 and CsCu2I3 films took only a few seconds by direct heating or exposure to the polar solvent. This work may deepen the understanding of the phase transition process in Cu-based perovskites and provide a fluorescence material with a short switching time for anticounterfeiting applications.