1D Pb halide perovskite-like materials for high performance X-ray detection.

The strategy of bandgap regulation is important for X-ray detection, but has not been reported for 1D Pb halide perovskite materials. In this work, three such materials, 1, 2 and 3, with a tunable bandgap, were fabricated for application in X-ray detection. 3 shows high sensitivity, far superior to commercial X-ray detectors.

Layered Chalcogenide Scintillators Enabled by Reversible Hydrous-Induced Phase Transformation for High-Resolution X-ray Imaging.

Scintillation materials have been widely used in various fields, such as medical diagnosis and industrial detection. Chalcogenides have the potential to become a new generation of high-performance scintillation materials due to their high effective atomic number and good resistance to radiation damage. However, research on their application in radiation detection is currently very scarce. Herein, single crystals of rare earth ion-doped ternary chalcogenides NaGaS2/Eu were grown by a high-temperature solid-phase method. It exhibits unique characteristics of structure transformation by absorbing water molecules from the air. To maintain the anhydrous phase of the material, we have used a strategy of organic-inorganic composites of epoxy resin and NaGaS2/Eu to prepare devices for radiation detection and discuss the irradiation luminescence properties of the two phases. The anhydrous phase of NaGaS2/Eu demonstrates excellent sensitivity to X-rays, with a low detection limit of 250 nGy s-1, which is approximately 1/22 of the medical imaging dose. Additionally, composite flexible films were prepared, which exhibited excellent performance in X-ray imaging. These films enable clear observation of a wide range of objects with a high spatial resolution of up to 13.2 line pairs per millimeter (lp mm-1), indicating that chalcogenide holds promising prospects in the realm of X-ray imaging applications.

Prediction of the Development Trend of the "Internet +" Logistics Industry under the "Belt and Road" Strategy.

In order to accurately predict the development trend of the "Internet +" logistics industry in the context of the new period and to understand the circulation of the Internet and logistics between countries and the development dynamics of the economy, this paper will take the "Belt and Road" initiative as the research background and elaborate the specific development mode of the "Internet +" logistics industry and the corresponding strategies. Meanwhile, the development trend is evaluated based on its development data using the method of combined forecasting. The results show that the combined prediction results fluctuate within the range of 1, indicating a high degree of prediction accuracy. This is important for predicting the trend of development forces and adjusting the strategic approach and development direction.

Development of a coupled geophysical-geothermal scheme for quantification of hydrates in gas hydrate-bearing permafrost sediments.

Quantification of hydrates in permafrost sediments using conventional seismic techniques has always been a major challenge in the study of the climate-driven evolution of gas hydrate-bearing permafrost sediments due to almost identical acoustic properties of hydrates and ice. In this article, a coupled geophysical-geothermal scheme is developed, for the first time, to predict hydrate saturation in gas hydrate-bearing permafrost sediments by utilising their geophysical and geothermal responses. The scheme includes a geophysical part which interprets the measured elastic wave velocities using a rock-physics model, coupled with a geothermal part, interpreting the measured effective thermal conductivity (ETC) using a new pore-scale model. By conducting a series of sensitivity analyses, it is shown that the ETC model is able to incorporate the effect of the hydrate pore-scale habit and hydrate/ice-forced heave as well as the effect of unfrozen water saturation under frozen conditions. Given that the geophysical and geothermal responses depend on the overburden pressure, the elastic wave velocities and ETC of methane hydrate-bearing permafrost sediment samples were measured at different effective overburden pressures and the results were provided. These experimental data together with the results of our recent study on the geophysical and geothermal responses of gas hydrate-bearing permafrost sediment samples at different hydrate saturations are used to validate the performance of the coupled scheme. By comparing the predicted saturations with those obtained experimentally, it is shown that the coupled scheme is able to quantify the saturation of the co-existing phases with an acceptable accuracy in a wide range of hydrate saturations and at different overburden pressures.

Insights into the climate-driven evolution of gas hydrate-bearing permafrost sediments: implications for prediction of environmental impacts and security of energy in cold regions.

The present study investigates the evolution of gas hydrate-bearing permafrost sediments against the environmental temperature change. The elastic wave velocities and effective thermal conductivity (ETC) of simulated gas hydrate-bearing sediment samples were measured at a typical range of temperature in permafrost and wide range of hydrate saturation. The experimental results reveal the influence of several complex and interdependent pore-scale factors on the elastic wave velocities and ETC. It was observed that the geophysical and geothermal properties of the system are essentially governed by the thermal state, saturation and more significantly, pore-scale distribution of the co-existing phases. In particular, unfrozen water content substantially controls the heat transfer at sub-zero temperatures close to the freezing point. A conceptual pore-scale model was also proposed to describe the pore-scale distribution of each phase in a typical gas hydrate-bearing permafrost sediment. This study underpins necessity of distinguishing ice from gas hydrates in frozen sediments, and its outcome is essential to be considered not only for development of large-scale permafrost monitoring systems, bus also accurate quantification of natural gas hydrate as a potential sustainable energy resource in cold regions.

Design and synthesis of novel methoxypyridine-derived gamma-secretase modulators.

The evolution of gamma-secretase modulators (GSMs) through the introduction of novel heterocycles with the goal of aligning activity for reducing the levels of Aß42 and properties consistent with a drug-like molecule are described. The insertion of a methoxypyridine motif within the tetracyclic scaffold provided compounds with improved activity for arresting Aß42 production as well as improved properties, including solubility. In vivo pharmacokinetic analysis demonstrated that several compounds within the novel series were capable of crossing the BBB and accessing the therapeutic target. Treatment with methoxypyridine-derived compound 64 reduced Aß42 levels in the plasma of J20 mice, in addition to reducing Aß42 levels in the plasma and brain of Tg2576 mice.

Thermodynamic and transport properties of hydrogen containing streams.

The use of hydrogen (H2) as a substitute for fossil fuel, which accounts for the majority of the world's energy, is environmentally the most benign option for the reduction of CO2 emissions. This will require gigawatt-scale storage systems and as such, H2 storage in porous rocks in the subsurface will be required. Accurate estimation of the thermodynamic and transport properties of H2 mixed with other gases found within the storage system is therefore essential for the efficient design for the processes involved in this system chain. In this study, we used the established and regarded GERG-2008 Equation of State (EoS) and SuperTRAPP model to predict the thermo-physical properties of H2 mixed with CH4, N2, CO2, and a typical natural gas from the North-Sea. The data covers a wide range of mole fraction of H2 (10-90 Mole%), pressures (0.01-100 MPa), and temperatures (200-500 K) with high accuracy and precision. Moreover, to increase ease of access to the data, a user-friendly software (H2Themobank) is developed and made publicly available.

Gas hydrates in sustainable chemistry.

Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination. Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates. This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies. This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade. Challenges, limitations, and future perspectives of each field are briefly discussed. The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field.

An Experimental Investigation on the Kinetics of Integrated Methane Recovery and CO2 Sequestration by Injection of Flue Gas into Permafrost Methane Hydrate Reservoirs.

Large hydrate reservoirs in the Arctic regions could provide great potentials for recovery of methane and geological storage of CO2. In this study, injection of flue gas into permafrost gas hydrates reservoirs has been studied in order to evaluate its use in energy recovery and CO2 sequestration based on the premise that it could significantly lower costs relative to other technologies available today. We have carried out a series of real-time scale experiments under realistic conditions at temperatures between 261.2 and 284.2 K and at optimum pressures defined in our previous work, in order to characterize the kinetics of the process and evaluate efficiency. Results show that the kinetics of methane release from methane hydrate and CO2 extracted from flue gas strongly depend on hydrate reservoir temperatures. The experiment at 261.2 K yielded a capture of 81.9% CO2 present in the injected flue gas, and an increase in the CH4 concentration in the gas phase up to 60.7 mol%, 93.3 mol%, and 98.2 mol% at optimum pressures, after depressurizing the system to dissociate CH4 hydrate and after depressurizing the system to CO2 hydrate dissociation point, respectively. This is significantly better than the maximum efficiency reported in the literature for both CO2 sequestration and methane recovery using flue gas injection, demonstrating the economic feasibility of direct injection flue gas into hydrate reservoirs in permafrost for methane recovery and geological capture and storage of CO2. Finally, the thermal stability of stored CO2 was investigated by heating the system and it is concluded that presence of N2 in the injection gas provides another safety factor for the stored CO2 in case of temperature change.

CO2 Capture by Injection of Flue Gas or CO2-N2 Mixtures into Hydrate Reservoirs: Dependence of CO2 Capture Efficiency on Gas Hydrate Reservoir Conditions.

Injection of flue gas or CO2-N2 mixtures into gas hydrate reservoirs has been considered as a promising option for geological storage of CO2. However, the thermodynamic process in which the CO2 present in flue gas or a CO2-N2 mixture is captured as hydrate has not been well understood. In this work, a series of experiments were conducted to investigate the dependence of CO2 capture efficiency on reservoir conditions. The CO2 capture efficiency was investigated at different injection pressures from 2.6 to 23.8 MPa and hydrate reservoir temperatures from 273.2 to 283.2 K in the presence of two different saturations of methane hydrate. The results showed that more than 60% of the CO2 in the flue gas was captured and stored as CO2 hydrate or CO2-mixed hydrates, while methane-rich gas was produced. The efficiency of CO2 capture depends on the reservoir conditions including temperature, pressure, and hydrate saturation. For a certain reservoir temperature, there is an optimum reservoir pressure at which the maximum amount of CO2 can be captured from the injected flue gas or CO2-N2 mixtures. This finding suggests that it is essential to control the injection pressure to enhance CO2 capture efficiency by flue gas or CO2-N2 mixtures injection.

Initial optimization and series evolution of diaminopyrimidine inhibitors of interleukin-1 receptor associated kinase 4.

IRAK4 plays a key role in TLR/IL-1 signaling. Previous efforts identified a series of aminopyrimidine IRAK4 inhibitors that possess good potency, but modest kinase selectivity. Exploration of substituents at the C-2 and C-5 positions generated compounds that maintained IRAK4 potency and improved kinase selectivity. Additionally, it was found that the pyrimidine core could be replaced with a pyridine and still retain potency and kinase selectivity. The optimization efforts led to compound 26 which had an IRAK4 IC50 of 0.7 nM, an IC50 of 55 nM on THP-1 cells stimulated with LPS, a TLR4 agonist, and greater than 100-fold selectivity versus 96% of a panel of 306 kinases.

Discovery and hit-to-lead optimization of 2,6-diaminopyrimidine inhibitors of interleukin-1 receptor-associated kinase 4.

Interleukin receptor-associated kinase 4 (IRAK4) is a critical element of the Toll-like/interleukin-1 receptor inflammation signaling pathway. A screening campaign identified a novel diaminopyrimidine hit that exhibits weak IRAK4 inhibitory activity and a ligand efficiency of 0.25. Hit-to-lead activities were conducted through independent SAR studies of each of the four pyrimidine substituents. Optimal activity was observed upon removal of the pyrimidine C-4 chloro substituent. The intact C-6 carboribose is required for IRAK4 inhibition. Numerous heteroaryls were tolerated at the C-5 position, with azabenzothiazoles conferring the best activities. Aminoheteroaryls were preferred at the C-2 position. These studies led to the discovery of inhibitors 35, 36, and 38 that exhibit nanomolar inhibition of IRAK4, improved ligand efficiencies, and modest kinase selectivities.

The optimization of pyridazinone series of glucan synthase inhibitors.

A detailed structure-activity relationship study of a novel series of pyridazine-based small molecule glucan synthase inhibitors is described. The optimization of the PK profile of this series led to the discovery of compound 11g, which demonstrated in vivo potency ip in a lethal fungal infection model.

SAR studies of pyridazinone derivatives as novel glucan synthase inhibitors.

A novel series of pyridazinone analogs has been developed as potent ß-1,3-glucan synthase inhibitors through structure-activity relationship study of the lead 5-[4-(benzylsulfonyl)piperazin-1-yl]-4-morpholino-2-phenyl-pyridazin-3(2H)-one (1). The effect of changes to the core structure is described in detail. Optimization of the sulfonamide moiety led to the identification of important compounds with much improved systematic exposure while retaining good antifungal activity against the fungal strains Candida glabrata and Candida albicans.

CO2 hydrates could provide secondary safety factor in subsurface sequestration of CO2.

Subsurface storage of carbon dioxide (CO(2)) is regarded as a short to medium term solution for reducing greenhouse gas emissions. However, there are concerns with respect to the integrity of seals in subsurface storage of CO(2) and the risks associated with leakage to ocean and atmosphere. In this paper, we report the results of experimental laboratory simulation of CO(2) leakage from subsurface storage sites and the self-sealing mechanism of CO(2) hydrates in subsea sediments, using an experimental setup specifically constructed for this work. The results demonstrate that the sequestrated CO(2) migrated upward and formed hydrates with the pore water in the sediment when the pressure and temperature conditions in the sediments were inside the hydrate stability zone. The CO(2) hydrate formation slowed down the CO(2) diffusion rate by several times to 3 orders of magnitude. The upward migrating CO(2) tended to form hydrate at the base of the hydrate stability zone. On the geological time scale the CO(2) hydrate formation could create a low-permeability secondary cap layer which greatly restricts further upward CO(2) flow, should a leakage occurs. This potential "self-sealing" and "self-healing" process could be an important criterion in the selection of suitable sites for geological storage of CO(2).

Construction of an advanced tetracyclic intermediate for total synthesis of the marine alkaloid sarain A.

In work directed toward a total synthesis of the marine alkaloid sarain A (1), the advanced intermediate 54, containing all the key elements and the seven stereogenic centers of sarain A, has been successfully synthesized from bicyclic lactam 4, previously prepared via an intramolecular stereospecific [3 + 2]-azomethine ylide dipolar cycloaddition. Intermediate lactam 4 could be efficiently converted to N-Boc derivative 12. Introduction of a two-carbon fragment into lactam 12 which eventually becomes the C-7',8' syn diol of the "eastern" ring was then achieved by C-acylation of the corresponding enolate with methoxyacetyl chloride followed by a highly stereoselective ketone reduction with Zn(BH4)2 to afford alcohol 16. Intermediate 16 has the incorrect C-7' relative stereochemistry for sarain A, but this problem was conveniently remedied by inverting the C-7' center via an intramolecular Ohfune-type cyclization of the silyl carbamate derived from Boc mesylate 27 to produce the key cyclic carbamate 28. It was then possible to convert acetal 28 to allylsilane 32 followed by cyclization to the alkaloid tricyclic core 33 via an allylsilane/N-sulfonyliminium ion cyclization. Formation of the "western" macrocyclic ring has been successfully addressed using functional group handles at C-3' and N-1' on the tricyclic core via a ring-closing olefin metathesis (RCM) strategy with the second-generation Grubbs ruthenium catalyst to produce intermediate macrolactam 47. A chelation-controlled addition of ethynylmagnesium bromide to advanced aldehyde 51 afforded a single diastereomeric adduct 53 which is tentatively assigned to have the correct C-7',8' syn-diol stereochemistry. This adduct could be rearranged to the conveniently protected amino carbonate 54 which is set up for construction of the remainder of the eastern ring of sarain A.