High Spatial Resolution 2D Imaging of Current Density and Pressure for Graphene Devices under High Pressure Using Nitrogen-Vacancy Centers in Diamond.

Current density imaging is helpful for discovering interesting electronic phenomena and understanding carrier dynamics, and by combining pressure distributions, several pressure-induced novel physics may be comprehended. In this work, noninvasive, high-resolution two-dimensional images of the current density and pressure gradient for graphene ribbon and hBN-graphene-hBN devices are explored using nitrogen-vacancy (NV) centers in diamond under high pressure. The two-dimensional vector current density is reconstructed by the vector magnetic field mapped by the near-surface NV center layer in the diamond. The current density images accurately and clearly reproduce the complicated structure and current flow of graphene under high pressure. Additionally, the spatial distribution of the pressure is simultaneously mapped, rationalizing the nonuniformity of the current density under high pressure. The current method opens a significant new avenue to investigate electronic transport and conductance variations in two-dimensional materials and electrical devices under high pressure as well as for nondestructive evaluation of semiconductor circuits.

Research on the mechanism of threefold discrepancy in thermal conductivity between room temperature and phase transition temperature for 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystals.

Cracks originating from thermal expansion and thermally induced phase transitions significantly hinder thermal conduction in certain energetic materials. For 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystals, a classic explosive, their temperature-dependent thermal conductivity serves as a crucial parameter determining safety and stability. In this work, the thermal conductivity of HMX single crystals before and after thermal damage under different heating conditions was measured and calculated, as well as the thermal conductivity of different regions of each single crystal. A threefold discrepancy in thermal conductivity was observed between room temperature and the phase transition temperature of the HMX crystal. The different effects of different types of damage and cracks, characterized by using 3D X-ray computed tomography (CT), on the thermal conduction process of the crystal were further analyzed. The results indicate that different heating methods influence the phase transformation of the crystals and the distributions of fast cracks and small cracks. The strong directivity of the fast cracks will significantly impact the thermal conductivity along two horizontal directions, whereas small cracks exert the greatest influence on the primary direction of heat conduction. The relevant conclusions were also verified by finite element analysis (FEA) modeling.

Dynamic Response of Ion Transport in Nanoconfined Electrolytes.

Ion transport in nanoconfined electrolytes exhibits nonlinear effects caused by large driving forces and pronounced boundary effects. An improved understanding of these impacts is urgently needed to guide the design of key components of the electrochemical energy systems. Herein, we employ a nonlinear Poisson-Nernst-Planck theory to describe ion transport in nanoconfined electrolytes coupled with two sets of boundary conditions to mimic different cell configurations in experiments. A peculiar nonmonotonic charging behavior is discovered when the electrolyte is placed between a blocking electrode and an electrolyte reservoir, while normal monotonic behaviors are seen when the electrolyte is placed between two blocking electrodes. We reveal that impedance shapes depend on the definition of surface charge and the electrode potential. Particularly, an additional arc can emerge in the intermediate-frequency range at potentials away from the potential of zero charge. The obtained insights are instrumental to experimental characterization of ion transport in nanoconfined electrolytes.

PRDM16 Is a Compact Myocardium-Enriched Transcription Factor Required to Maintain Compact Myocardial Cardiomyocyte Identity in Left Ventricle.

BACKGROUND: Left ventricular noncompaction cardiomyopathy (LVNC) was discovered half a century ago as a cardiomyopathy with excessive trabeculation and a thin ventricular wall. In the decades since, numerous studies have demonstrated that LVNC primarily has an effect on left ventricles (LVs) and is often associated with LV dilation and dysfunction. However, in part because of the lack of suitable mouse models that faithfully mirror the selective LV vulnerability in patients, mechanisms underlying the susceptibility of LVs to dilation and dysfunction in LVNC remain unknown. Genetic studies have revealed that deletions and mutations in PRDM16 (PR domain-containing 16) cause LVNC, but previous conditional Prdm16 knockout mouse models do not mirror the LVNC phenotype in patients, and the underlying molecular mechanisms by which PRDM16 deficiency causes LVNC are still unclear. METHODS: Prdm16 cardiomyocyte-specific knockout (Prdm16cKO) mice were generated and analyzed for cardiac phenotypes. RNA sequencing and chromatin immunoprecipitation deep sequencing were performed to identify direct transcriptional targets of PRDM16 in cardiomyocytes. Single-cell RNA sequencing in combination with spatial transcriptomics was used to determine cardiomyocyte identity at the single-cell level. RESULTS: Cardiomyocyte-specific ablation of Prdm16 in mice caused LV-specific dilation and dysfunction, as well as biventricular noncompaction, which fully recapitulated LVNC in patients. PRDM16 functioned mechanistically as a compact myocardium-enriched transcription factor that activated compact myocardial genes while repressing trabecular myocardial genes in LV compact myocardium. Consequently, Prdm16cKO LV compact myocardial cardiomyocytes shifted from their normal transcriptomic identity to a transcriptional signature resembling trabecular myocardial cardiomyocytes or neurons. Chamber-specific transcriptional regulation by PRDM16 was attributable in part to its cooperation with LV-enriched transcription factors Tbx5 and Hand1. CONCLUSIONS: These results demonstrate that disruption of proper specification of compact cardiomyocytes may play a key role in the pathogenesis of LVNC. They also shed light on underlying mechanisms of the LV-restricted transcriptional program governing LV chamber growth and maturation, providing a tangible explanation for the susceptibility of LV in a subset of LVNC cardiomyopathies.

Immunomagnetic Separation Method Integrated with the Strep-Tag II System for Rapid Enrichment and Mild Release of Exosomes.

Exosomes are important participants in numerous pathophysiological processes and hold promising application value in cancer diagnosis, monitoring, and prognosis. However, the small size (40-160 nm) and high heterogeneity of exosomes make it still challenging to enrich exosomes efficiently from the complex biological fluid microenvironment, which has largely restricted their downstream analysis and clinical application. In this work, we introduced a novel method for rapid isolation and mild release of exosomes from the cell culture supernatant. A Strep-tag II-based immunomagnetic isolation (SIMI) system was constructed by modifying the capture antibodies onto magnetic nanoparticles through specific and reversible recognition between Strep-Tactin and Strep-tag II. Due to their high affinity and binding selectivity, exosomes could be isolated within 38 min with an isolation efficiency of 82.5% and a release efficiency of 62%. Compared with the gold-standard ultracentrifugation, the SIMI system could harvest nearly 59% more exosomes from the 293 T cell culture medium with shorter isolation time and higher purity. In addition, cellular uptake assay indicated that exosomes released from magnetic nanoparticles could maintain their high biological activity. These superior characteristics show that this novel method is a fast, efficient, and nondestructive exosome isolation tool and thus could potentially be further utilized in various exosome-related applications, e.g., disease diagnosis and drug delivery.

Automated quantification and statistical assessment of proliferating cardiomyocyte rates in embryonic hearts.

The use of digital image analysis and count regression models contributes to the reproducibility and rigor of histological studies in cardiovascular research. The use of formalized computer-based quantification strategies of histological images essentially removes potential researcher bias, allows for higher analysis throughput, and enables easy sharing of formalized quantification tools, contributing to research transparency, and data transferability. Moreover, the use of count regression models rather than ratios in statistical analysis of cell population data incorporates the extent of sampling into analysis and acknowledges the non-Gaussian nature of count distributions. Using quantification of proliferating cardiomyocytes in embryonic murine hearts as an example, we describe how these improvements can be implemented using open-source artificial intelligence-based image analysis tools and novel count regression models to efficiently analyze real-life data.

Isothermal structural evolution of CL-20/HMX cocrystals under slow roasting at 190 °C.

As a new type of energetic material, cocrystal explosives demonstrate many excellent properties, such as high energy density and low sensitivity, due to the interaction between the molecules of the two components. The known decomposition temperature is 235 °C for CL-20/HMX cocrystals at a faster heating rate. CL-20 molecules could separate from the cocrystal matrix and decompose at a higher temperature, much lower than the decomposition temperature. The current work provided deep insight into the isothermal structural evolution of CL-20/HMX cocrystals with slow roasting at 190 °C. We found that the initial decomposition originates from separating CL-20 molecules from the surface along the (010) plane of the cocrystals. The gas products, such as NO2 and NO, escape from the largest exposed surface of the (010) plane and generates microbubbles and microholes. At the same time, the residual HMX molecules form δ-phase HMX crystals and shrink the volume by 72%. By increasing the time held at 190 °C, the decomposition of CL-20 molecules and recrystallization of the residual HMX molecules form a gully-like structure on the (010) plane of the CL-20/HMX cocrystal. After a long time at 190 °C, the CL-20 component completely decomposes, and all HMX molecules recrystallize in the δ-HMX form. The interaction between HMX and CL-20 molecules makes the decomposition rate of the CL-20/HMX cocrystal much slower than that of the CL-20 pure crystal with a similar decomposition activation energy during isothermal heating. This work can help to deeply understand the safety of CL-20/HMX cocrystal explosives at a temperature lower than the recognized decomposition temperature.

An animal model for mitochondrial tyrosyl-tRNA synthetase deficiency reveals links between oxidative phosphorylation and retinal function.

Mitochondria maintain a distinct pool of ribosomal machinery, including tRNAs and tRNAs activating enzymes, such as mitochondrial tyrosyl-tRNA synthetase (YARS2). Mutations in YARS2, which typically lead to the impairment of mitochondrial protein synthesis, have been linked to an array of human diseases including optic neuropathy. However, the lack of YARS2 mutation animal model makes us difficult to elucidate the pathophysiology underlying YARS2 deficiency. To explore this system, we generated YARS2 knockout (KO) HeLa cells and zebrafish using CRISPR/Cas9 technology. We observed the aberrant tRNATyr aminoacylation overall and reductions in the levels in mitochondrion- and nucleus-encoding subunits of oxidative phosphorylation system (OXPHOS), which were especially pronounced effects in the subunits of complex I and complex IV. These deficiencies manifested the decreased levels of intact supercomplexes overall. Immunoprecipitation assays showed that YARS2 bound to specific subunits of complex I and complex IV, suggesting the posttranslational stabilization of OXPHOS. Furthermore, YARS2 ablation caused defects in the stability and activities of OXPHOS complexes. These biochemical defects could be rescued by the overexpression of YARS2 cDNA in the YARS2KO cells. In zebrafish, the yars2KO larva conferred deficient COX activities in the retina, abnormal mitochondrial morphology, and numbers in the photoreceptor and retinal ganglion cells. The zebrafish further exhibited the retinal defects affecting both rods and cones. Vision defects in yars2KO zebrafish recapitulated the clinical phenotypes in the optic neuropathy patients carrying the YARS2 mutations. Our findings highlighted the critical role of YARS2 in the stability and activity of OXPHOS and its pathological consequence in vision impairments.

A sample-to-answer DNA detection microfluidic system integrating sample pretreatment and smartphone-readable gradient plasmonic photothermal continuous-flow PCR.

As the gold standard for nucleic acid detection, full-process polymerase chain reaction (PCR) analysis often falls into the dilemma of complex workflow, time-consuming, and high equipment costs. Therefore, we designed and optimized a DNA quantification microfluidic system by strategically integrating sample pretreatment and a smartphone-readable gradient plasmonic photothermal (GPPT) continuous-flow PCR (CF-PCR). Through preloading and sequential injection of immiscible extraction reagents, combined with magnetic bead (MB) manipulation, the microfluidic chip successfully purified and concentrated 100 µL of HBV-DNA spiked plasma into a 20-µL purified sample within 14 minutes. With a digital PCR platform, the optimized experiments showed that the DNA extraction efficiency can reach 69% at an immiscible reagent configuration ratio of 10 : 10 : 1 : 12 : 2 (sample : lysis/binding buffer : MB : silicone oil : eluent) and a flow rate of 25 µL min-1. For the first time, we used gold nanorod (AuNR)-doped PDMS to prepare a CF-PCR submodule for the amplification of a 40 µL PCR mixture. Due to the plasmonic photothermal effect of AuNRs and the gradient intensity of an expanded laser spot, the PCR thermal gradient was formed on a coin-sized area. The compact annular thermal-microfluidic layout, optimized DNA dye concentration, and chip transmittance synergistically enable a rarely reported smartphone-based fluorescence CF-PCR, greatly simplifying thermal control and detection setup. Prototype construction and validation experiments show that the microsystem can complete the sample-to-answer quantification of HBV-DNA with a dynamic linear range from 1.2 × 101 to 1.2 × 106 copies per µL in ∼37 minutes. This novel microfluidic solution effectively bridges the technical gap between the CF-PCR, sample pretreatment and result characterization, making the workflow standardized and rapid and requiring <15% of the commercial instrument cost. The simplicity, rapidity and low cost of this work make it promising for applications in decentralized laboratories and low-resource settings.

Orthorhombic-to-Hexagonal Phase Transition of REF3 (RE = Sm to Lu and Y) under High Pressure.

For the famous functional REF3 family, there exist two typical structures, that is, orthorhombic phase and hexagonal phase. In the present work, high pressure behaviors of the orthorhombic phase REF3 (RE = Sm to Lu and Y) were investigated by experimental methods and first-principles calculations. The pressure-induced phase transitions of GdF3, TbF3, YbF3, and LuF3 were studied by using in situ photoluminescence measurements in the diamond anvil cell. At room temperature, all these four compounds follow the phase transition route from orthorhombic to hexagonal phase at 5.5-20.6 GPa. The pressure ranges of phase transition are 5.5-9.3, 8.4-11.9, 13.5-20.3, and 14.8-20.6 GPa for GdF3, TbF3, YbF3, and LuF3, respectively. In combination with first-principles calculations, we infer that all orthorhombic REF3 members from Sm-Lu and Y obey the same orthorhombic-to-hexagonal phase transition rules under high pressures. For lanthanide trifluorides, the transition pressures increase as zero pressure volumes of REF3 in the orthorhombic phase become smaller. As the calculation results show, this is because the difference in value of energy from the two structures is larger. This work not only provides precise structural change but also benefits the understanding of two typical structures for rare-earth trifluorides, which may play a significant role in the applications of REF3.

Pressure effects on the thermal decomposition of the LLM-105 crystal.

Thermal mechanical responses under high temperature and high pressure are basic information to understand the performance of energetic materials. In this work, the pressure effects on the thermal decay of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) are explored. Up to the initial pressure of 4.6 GPa, the pressure dependent decomposition boundary is built and no phase transition occurs until the decomposition of the LLM-105 crystal. The decomposition temperature is significantly lifted via a weak loading pressure. The experimental measurement confirms the decomposition products, including NO2, CO2 and NH3, which are predicted by the density functional tight-binding molecular dynamics method. The calculation described the details of thermal decay in the initial stages under high pressure. The sudden drop in the shifts of the Raman modes associated with hydrogen bonds under high pressure indicates the strengthening of the intermolecular hydrogen bonds and the occurrence of intermolecular hydrogen transfer prior to crystal decomposition. The simulation supported the existence of intermolecular hydrogen transfer and provided the transfer path and decomposition mechanism. All of these jobs not only contribute significantly to the understanding of thermal decomposition of energetic materials as a function of pressure, but also contribute to the understanding of sensitivity mechanisms and safety issues.

Inference of a "Hot Ice" Layer in Nitrogen-Rich Planets: Demixing the Phase Diagram and Phase Composition for Variable Concentration Helium-Nitrogen Mixtures Based on Isothermal Compression.

Van der Waals (vdW) chemistry in simple molecular systems may be important for understanding the structure and properties of the interiors of the outer planets and their satellites, where pressures are high and such components may be abundant. In the current study, Raman spectra and visual observation are employed to investigate the phase separation and composition determination for helium-nitrogen mixtures with helium concentrations from 20 to 95% along the 295 K isothermal compression. Fluid-fluid-solid triple-phase equilibrium and several equilibria of two phases including fluid-fluid and fluid-solid have been observed in different helium-nitrogen mixtures upon loading or unloading pressure. The homogeneous fluid in helium-nitrogen mixtures separates into a helium-rich fluid (F1) and a nitrogen-rich fluid (F2) with increasing pressure. The triple-phase point occurs at 295 K and 8.8 GPa for a solid-phase (N2)11He vdW compound, fluid F1 with around 50% helium, and fluid F2 with 95% helium. Helium concentrations of F1 coexisted with the (N2)11He vdW compound or δ-N2 in helium-nitrogen mixtures with different helium concentrations between 40 and 50% and between 20 and 40%, respectively. In addition, the helium concentration of F2 is the same in helium-nitrogen mixtures with different helium concentrations and decreases upon loading pressure. Pressure-induced nitrogen molecule ordering at 32.6 GPa and a structural phase transition at 110 GPa are observed in (N2)11He. In addition, at 187 GPa, a pressure-induced transition to an amorphous state is identified.

Possible Topological Hall Effect above Room Temperature in Layered Cr1.2Te2 Ferromagnet.

Topological Hall effect (THE) has been used as a powerful tool to unlock spin chirality in novel magnetic materials. Recent focus has been widely paid to THE and possible chiral spin textures in two-dimensional (2D) layered magnetic materials. However, the room-temperature THE has been barely reported in 2D materials, which hinders its practical applications in 2D spintronics. In this paper, we report a possible THE signal featuring antisymmetric peaks in a wide temperature window up to 320 K in Cr1.2Te2, a new quasi-2D ferromagnetic material. The temperature, thickness, and magnetic field dependences of the THE lead to potential spin chirality origin that is associated with the spin canting under external magnetic fields. Our work holds promise for practical applications in future chiral spin-based vdW spintronic devices.

Massive droplet generation for digital PCR via a smart step emulsification chip integrated in a reaction tube.

Step emulsification (SE) devices coupled with parallel generation nozzles are widely used in the production of large-scale monodisperse droplets, especially for droplet-based digital polymerase chain reaction (ddPCR) analysis. Although current ddPCR systems based on the SE method can provide a fully enclosed ddPCR scheme, high demands on chip fabrication and system control will increase testing costs and reduce its flexibility in ddPCR analysis. In this study, a compact SE device, integrating a smart SE chip into a reaction tube, was developed to prepare large-scale water-in-fluorinated-oil droplets for ddPCR analysis. The SE chip contained dozens of droplet-generation nozzles. By adjusting the nozzle height of the SE chip, monodisperse droplets in a picolitre to nanolitre vloume could be prepared at a production rate of tens to hundreds of microlitres per minute. Subsequently, we utilized such an integrated SE device to prepare monodisperse droplets for ddPCR experiments. The volume of PCR reagent and the number of droplets could be flexibly adjusted according to the requirements of the ddPCR analysis. The quantitative results showed that emulsions prepared by the SE device could achieve ddPCR detection with high accuracy, good repeatability, and an adaptive dynamic range, which also demonstrated the robustness and reliability of such devices in the droplet preparation. Thus, this compact SE device provides an inexpensive, flexible, and simplified droplet preparation method for digital PCR quantitative analysis.

Deletion of Gtpbp3 in zebrafish revealed the hypertrophic cardiomyopathy manifested by aberrant mitochondrial tRNA metabolism.

GTPBP3 is a highly conserved tRNA modifying enzyme for the biosynthesis of τm5U at the wobble position of mitochondrial tRNAGlu, tRNAGln, tRNALys, tRNATrp and tRNALeu(UUR). The previous investigations showed that GTPBP3 mutations were associated with hypertrophic cardiomyopathy (HCM). However, the pathophysiology of GTPBP3 deficiency remains elusively. Using the gtpbp3 knockout zebrafish generated by CRISPR/Cas9 system, we demonstrated the aberrant mitochondrial tRNA metabolism in gtpbp3 knock-out zebrafish. The deletion of gtpbp3 may alter functional folding of tRNA, indicated by conformation changes and sensitivity to S1-mediated digestion of tRNAGlu, tRNALys, tRNATrp and tRNALeu(UUR). Strikingly, gtpbp3 knock-out zebrafish displayed the global increases in the aminoacylated efficiencies of mitochondrial tRNAs. The aberrant mitochondrial tRNA metabolisms impaired mitochondrial translation, produced proteostasis stress and altered activities of respiratory chain complexes. These mitochondria dysfunctions caused the alterations in the embryonic heart development and reduced fractional shortening of ventricles in mutant zebrafish. Notably, the gtpbp3 knock-out zebrafish exhibited hypertrophy of cardiomyocytes and myocardial fiber disarray in ventricles. These cardiac defects in the gtpbp3 knock-out zebrafish recapitulated the clinical phenotypes in HCM patients carrying the GTPBP3 mutation(s). Our findings highlight the fundamental role of defective nucleotide modifications of tRNAs in mitochondrial biogenesis and their pathological consequences in hypertrophic cardiomyopathy.

Smartphone-Based Droplet Digital LAMP Device with Rapid Nucleic Acid Isolation for Highly Sensitive Point-of-Care Detection.

While advances in microfluidics have enabled rapid and highly integrated detection of nucleic acid targets, the detection sensitivity is still unsatisfactory in the current POC (point-of-care) detection systems, especially for low abundance samples. In this study, a chip that integrates rapid nucleic acid extraction based on IFAST (immiscible phase filtration assisted by surface tension) and digital isothermal detection was developed to achieve highly sensitive POC detection within 60 min. Based on the interface theory, the factors influencing the interface stability of the IFAST process were studied, and the IFAST nucleic acid extraction conditions were optimized to increase the nucleic acid extraction recovery rate to 75%. Spiral mixing channel and flow-focusing droplet generation structure were designed to achieve the mixing and sample partitioning by applying negative pressure. A portable microdroplet fluorescence detection device was developed based on smartphone imaging. Validation tests were carried out for quantification of low-abundance cfDNA and detection of mutations.

Deletion of Mtu1 (Trmu) in zebrafish revealed the essential role of tRNA modification in mitochondrial biogenesis and hearing function.

Mtu1(Trmu) is a highly conserved tRNA modifying enzyme responsible for the biosynthesis of τm5s2U at the wobble position of tRNAGln, tRNAGlu and tRNALys. Our previous investigations showed that MTU1 mutation modulated the phenotypic manifestation of deafness-associated mitochondrial 12S rRNA mutation. However, the pathophysiology of MTU1 deficiency remains poorly understood. Using the mtu1 knock-out zebrafish generated by CRISPR/Cas9 system, we demonstrated the abolished 2-thiouridine modification of U34 of mitochondrial tRNALys, tRNAGlu and tRNAGln in the mtu1 knock-out zebrafish. The elimination of this post-transcriptional modification mediated mitochondrial tRNA metabolisms, causing the global decreases in the levels of mitochondrial tRNAs. The aberrant mitochondrial tRNA metabolisms led to the impairment of mitochondrial translation, respiratory deficiencies and reductions of mitochondrial ATP production. These mitochondria dysfunctions caused the defects in hearing organs. Strikingly, mtu1-/- mutant zebrafish displayed the abnormal startle response and swimming behaviors, significant decreases in the sizes of saccular otolith and numbers of hair cells in the auditory and vestibular organs. Furthermore, mtu1-/- mutant zebrafish exhibited the significant reductions in the hair bundle densities in utricle, saccule and lagena. Therefore, our findings may provide new insights into the pathophysiology of deafness, which was manifested by the deficient modifications at wobble position of mitochondrial tRNAs.

Wide-range ratiometric upconversion luminescence thermometry based on non-thermally coupled levels of Er in high-temperature cubic phase NaYF4: Yb, Er.

Wide-range optical thermal sensing is achieved here based on the two-photon upconversion luminescence of the high-temperature (HT) cubic phase NaYF4:Yb, Er. In the range of room temperature to 973 K, the single-phase sample exhibits two bands of green and red emission with different dependences on the temperature. The CIE chromaticity diagram shows that the color point moves from deep red (0.6357, 0.3501) at room temperature to the yellow region (0.4379, 0.475) at 600 K and then to the green region (0.318, 0.669) at 973 K. It reveals that HT cubic phase NaYF4:Yb, Er is the promising ratiometric and colorimetric luminescent thermometer. The relative sensitivity decreases slightly up to 673 K and then increases with the increasing temperature. The lattice expansion of the HT cubic phase alters the crystal symmetry around the activator ion and further increases the green-to-red emission ratio.

Rapid isolation of cfDNA from large-volume whole blood on a centrifugal microfluidic chip based on immiscible phase filtration.

Cell-free (cf) nucleic acids are considered important and have been used as selective biomarkers. Conventional techniques for cf nucleic acid biomarker isolation from blood are generally time-consuming, complicated, and expensive. This study describes a lab-on-a-disk system equipped with newly developed immiscible filtration assisted by surface tension (IFAST), which can achieve the rapid isolation of cfDNA from whole blood. The principle of centrifugal IFAST (C-IFAST) is introduced. An arch-like channel for magnetic bead transfer in the immiscible phase is designed, which builds both a virtual water-air "wall" and an air-oil "wall" to prevent the blending of water and oil. The entire process requires less than 15 min and achieves the recovery of 65% of cfDNA from plasma and 30% from whole blood. Experiments were performed to test the validity of the chip, showing that this technique takes less time to obtain results of identical quality compared to commercial kits. The proposed C-IFAST method enables rapid and reliable cfDNA isolation from large whole blood volume (4 ml) and can potentially be used in "liquid biopsy" point-of-care diagnosis.

Effect of pressure gradient and new phases for 1,3,5-trinitrohexahydro-s-triazine (RDX) under high pressures.

Herein, pressure-induced phase transitions of RDX up to 50 GPa were systematically studied under different compression conditions. Precise phase transition points were obtained based on high-quality Raman spectra with small pressure intervals. This favors the correctness of the theoretical formula for detonation and the design of a precision weapon. The experimental results indicated that α-RDX immediately transformed to γ-RDX at 3.5 GPa due to hydrostatic conditions and possible interaction between the penetrating helium and RDX, with helium gas as the pressure-transmitting medium (PTM). Mapping of pressure distribution in samples demonstrates that the pressure gradient is generated in the chamber and independent of other PTMs. The gradient induced the first phase transition starts at 2.3 GPa and completed at 4.1 GPa. The larger pressure gradient promoted phase transition in advance under higher pressures. Experimental results supported that there existed two conformers of AAI and AAE for γ-RDX, as proposed by another group. δ-RDX was considered to only occur in a hydrostatic environment around 18 GPa using helium as the PTM. This study confirms that δ-RDX is independent of PTM and exists under non-hydrostatic conditions. Evidence for a new phase (ζ) was found at about 28 GPa. These 4 phases have also been verified via XRD under high pressures. In addition to this, another new phase (η) may exist above 38 GPa, and it needs to be further confirmed in the future. Moreover, all the phase transitions were reversible after the pressure was released, and original α-RDX was always obtained at ambient pressure.