High-pressure Technique Research Articles

Formulation and Characterization of Febuxostat Loaded Nanostructured Lipid Carriers (NLCs) - Gel for Topical Treatment of Gout.

The aim of the present study was to formulate and characterize Nano- Structured Lipid Carriers (NLCs) of Febuxostat (FB) incorporated in the gel for the treatment of Gout. FB is a Xanthine Oxidase (XO) inhibitor drug used for chronic Gout and hyperuricemia. FB is a BCS class II drug, therefore, water solubility is very poor, and due to its poor solubility and wettability, it leads to poor dissolution. The hot high-pressure homogenization technique was used in this study to improve the physicochemical property of FB. The carbopol 934 was used to prepare NLCs gel of FB. The NLCs of FB was prepared in different drug: polymer ratios w/w (2:1), (1:1), (1:2), (1:3) and (1:4) with solid lipid (Stearic Acid) and liquid lipid (Oleic acid). The preformulation study of FB included FTIR study melting point, standard calibration curves, and drug-polymer interaction study. The NLCs (1:3) showed high entrapment and drug content. The NLCs gel formulation was 87% released within 6 hours in a controlled manner. NLCs gel modifies the drug release, increases the bioavailability, and reduces side effects of FB. The prepared gel is the efficient formulation for the better treatment of chronic gout and hyperuricemia. The research findings have shown the undesirable side effects associated with the oral route that can be reduced by the use of NLCs formulation through the transdermal route in an effective manner.

Full superconducting gap in the candidate topological superconductor In1−xPbxTe for x=0.2

High-pressure synthesis techniques have allowed for the growth of samples on the indium-rich side of (Pb,In)Te, which have increased superconducting transition temperatures compared to lead-rich compounds. In this study we present measurements of the temperature dependence of the London penetration depth $\Delta \lambda(T)$ in the compound In$_{0.8}$Pb$_{0.2}$Te, which shows a bulk $T_{c,onset}$ of $\sim4.75$ K. The results indicate fully gapped BCS-like behavior, ruling out odd-parity, topologically nontrivial $A_{2u}$ pairing; however, odd-parity $A_{1u}$ pairing is still possible. Critical field values measured below 1 K and other superconducting parameters are also presented.

Preparation, Characterization and Permeation Study of Topical Gel Loaded with Transfersomes Containing Asiatic Acid.

The objective of this study is to investigate the in vitro permeation of asiatic acid (AA) in the form of a topical gel after entrapment in transfersomes by Franz diffusion cells. Transfersomes composed of soybean lecithin and three different edge activators including Tween 80 (TW80), Span 80 (SP80) and sodium deoxycholate (SDC) at the ratio of 50:50, 90:10 and 90:10, respectively, together with 0.3% w/w of AA, were prepared by a high-pressure homogenization technique and further incorporated in gels (TW80AATG, SP80AATG and SDCAATG). All transfersomal gels were characterized for their AA contents, dynamic viscosity, pH and homogeneity. Results revealed that the AA content, dynamic viscosity and pH of the prepared transfersomal gels ranged from 0.272 ± 0.006 to 0.280 ± 0.005% w/w, 812.21 ± 20.22 to 1222.76 ± 131.99 Pa.s and 5.94 ± 0.03 to 7.53 ± 0.03, respectively. TW80AATG gave the highest percentage of AA penetration and flux into the Strat-M® membrane at 8 h (8.53 ± 1.42% and 0.024 ± 0.008 mg/cm2/h, respectively) compared to SP80AATG (8.00 ± 1.70% and 0.019 ± 0.010 mg/cm2/h, respectively), SDCAATG (4.80 ± 0.50% and 0.014 ± 0.004 mg/cm2/h, respectively), non-transfersomal gels (0.73 ± 0.44 to 3.13 ± 0.46% and 0.002 ± 0.001 to 0.010 ± 0.002 mg/cm2/h, respectively) and hydroethanolic AA solution in gel (1.18 ± 0.76% and 0.004 ± 0.003 mg/cm2/h, respectively). These findings indicate that the TW80AATG might serve as a lead formulation for further development toward scar prevention and many types of skin disorders.

Incorporation of topotecan into sesame oil - Nanoemulsion potentiates its cytotoxic effect in cancer cells

PurposeTo incorporate the topoisomerase I inhibitor, topotecan (TOPO), into oil-in-water nanoemulsion delivery system based on sesame oil (SO-NE), with the aim to enhance its anti-proliferative effect on MCF-7 breast, HCT116 colon, HeLa cervical, and HepG2 liver cancer cells. MethodsSO-NE was formulated by mixing different volume fractions of SO (3%), Tween 80 (10%), Span 20 (5%), and water (82%) using the high-pressure ultrasonication technique. SO-NE and TOPO-loaded SO-NE (TOPO–SO–NE) were physically characterized by zeta sizer and transmission electron microscope. The in vitro drug release of TOPO–SO–NE relative to the free TOPO solution was assessed by the dialysis bag technique. The cytotoxicity of the TOPO–SO–NE formula was determined in vitro using crystal violet assay. DAPI fluorescent stains were used for cellular morphology and death assessments. Additionally, TOPO cellular uptake and inflammatory effect after TOPO loading into SO-NE formula were determined. ResultsSO-NE formula was found to have negatively charged nanosized particles even after TOPO loading (Z-diameter = 73.66 ± 5.5 nm, Zetapotential = −7.63 ± 0.24 mV). In addition, TOPO–SO–NE formulation exhibited a beneficial TOPO prolonged and sustained release over 24 h. In all tested cell lines, TOPO–SO–NE formula exhibited considerable anti-proliferation effect with decreased IC50 and caused distinct apoptotic changes in cancer cells, which was evidenced by the enhanced cellular uptake of TOPO. The concentrations of interlukin-6 (IL-6), an inflammatory marker, in MCF-7, HCT116 and HepG2 cells were suppressed by TOPO–SO–NE treatment, but they got reversed in HeLa cells. ConclusionIncorporation of TOPO into SO-NE has remarkably improved its cytotoxicity in MCF-7, HCT116, HeLa and HepG2 cancer cells. The mechanisms of cell death were through the induction of apoptosis, enhancement of TOPO cellular accumulation ratios and affecting the inflammatory agent, interlukin-6 (IL-6), concentrations.

Formulation and Characterization of O/W Nanoemulsions of Hemp Seed Oil for Protection from Steatohepatitis: Analysis of Hepatic Free Fatty Acids and Oxidation Markers.

Non-alcoholic steatohepatitis (NASH) is a common type of metabolic liver disease which is characterized by fatty changes associated with hepatocyte injury, lobular inflammation, and/or liver fibrosis. Nanoemulsions are kinetically stable colloidal systems characterized by small droplet size. Hemp seed oil is a natural oil derived from Cannabis sativa seeds. The current study was designed to formulate nanoemulsion preparations of hemp seed oil with promising enhanced biological activity against high fat (HF) diet induced NASH in rats. Four nanoemulsion formulas (NEFs) were formulated based on high-pressure homogenization technique and evaluated for droplet size, zeta potential (ZP), polydispersity index (PDI), electrical conductivity, pH, and viscosity, as well as the preparation stability. The best NEF was selected to perform an in vivo rat study; selection was based on the smallest droplet size and highest physical stability. Results showed that NEF#4 showed the best physiochemical characters among the other preparations. Twenty male rats were assigned to four groups as follows: normal, NASH control, NASH + hemp seed oil and NASH + hemp seed oil NEF4. The rats were tested for body weight (BWt) change, insulin resistance (IR) and hepatic pathology. The hemp seed NEF#4 protected against NASH progression in rats and decreased the % of BWt gain compared to the original Hemp seed oil. NEF#4 of Hemp seed oil showed greater protective activity against experimental NASH and IR in rats. Hence, we can consider the nanoemulsion preparations as a useful tool for enhancing the biological action of the hemp seed oil, and further studies are warranted for application of this technique for preparing natural oils aiming at enhancing their activities.

The neutron diffraction experiments under high pressure and high temperature on FENGHUANG diffractometer at CMRR

FENGHUANG diffractometer at CMRR, a high-intensity multi-section neutron powder diffractometer, has been constructed to in situ studies of materials under high pressure high temperature conditions. With development of anvils, high pressure high temperature cell assemblies, high pressure device and alignment system, we have been realized the angle-dispersive neutron diffraction data collect at the range of achievable pressures and temperatures of 0–30 GPa and 300–1500 K, with the sample size of millimeter scale. This paper describes the technical characteristics of diffractometer and related techniques for high pressure neutron diffraction experiments, and gives some scientific examples that have been recently performed on FENGHUANG. The experience gained experiments on FENGHUANG could help promote the development of high pressure techniques on neutron scattering facilities.

Nose to brain delivery of nanosuspensions with first line antiviral agents is alternative treatment option to Neuro-AIDS treatment

Intranasal drug delivery is one of the uprising areas of the research in targeting drug to the brain. Nose to brain drug delivery follows the olfactory pathway and purportedly known to be more efficient to deliver neuro-therapeutics to the brain by circumventing the BBB and thereby increasing bioavailability of drugs in the brain. The advantage of this method is non-invasiveness, rapid onset of action and helps to achieve site specific delivery. In this research work nanosuspension were prepared using combination of antiretroviral agents for Neuro-AIDS treatment. Nanosuspensions were prepared by high-speed homogenization, wet milling and high-pressure homogenization techniques. Formulations were analysed by SEM, FTIR, and DSC. Morphology and stability analysis was done by analysing zeta potential, particle size, and PDI. Ex-vivo diffusion study and histopathological analysis was performed using goat nasal mucosa. High pressure homogenization was found to be best technique for formulation of nanosuspension. Antiviral drugs could be delivered successfully by optimizing nasal dosage form.

Slight Co-doping tuned magnetic and electric properties on cubic BaFeO3 single crystal

The single crystal of cubic perovskite BaFeO3 shows multiple magnetic transitions and external stimulus sensitive magnetism. In this paper, a 5%-Co-doped BaFeO3 (i.e. BaFe0.95Co0.05O3) single crystal was grown by combining floating zone methods with high-pressure techniques. Such a slight Co doping has little effect on crystal structure, but significantly changes the magnetism from the parent antiferromagnetic ground state to a ferromagnetic one with the Curie temperature T C ≈ 120 K. Compared with the parent BaFeO3 at the induced ferromagnetic state, the saturated magnetic moment of the doped BaFe0.95Co0.05O3 increases by about 10% and reaches 3.64 μ B/f.u. Resistivity and specific heat measurements show that the ferromagnetic ordering favors metallic-like electrical transport behavior for BaFe0.95Co0.05O3. The present work indicates that Co-doping is an effective method to tune the magnetic and electric properties for the cubic perovskite phase of BaFeO3.

Dimensionality switching and superconductivity transition in dense 1T−HfSe2

The quest for new transition metal dichalcogenides (TMDs) with outstanding electronic properties is a particularly significant and interesting subject. The use of nonconventional methods of materials synthesis, especially pressure engineering, shows great potential for breakthrough discoveries in TMDs. Here, we employ the high-pressure techniques to successfully realize the transformation of two-dimensional semiconductor into three-dimensional superconducting states in $1T\text{\ensuremath{-}}{\mathrm{HfSe}}_{2}$. We unambiguously demonstrate that the enhancement of the interlayer coupling and the bonding between interlayer Se-Se atoms contribute to the emergence of nonlayered $C2/m$ and $I4/mmm$ phases. The discovered three-dimensional (3D) structures present excellent superconductivity compared to the original layered structure, and the superconducting critical temperature reaches a maximum of 5.8 K at around 50 GPa. Theoretical calculations reveal that the realization of superconductivity in these two 3D structures is related to the increase in the density of states at the Fermi surface $[N({\ensuremath{\varepsilon}}_{f})]$. The present results in ${\mathrm{HfSe}}_{2}$ may provide a platform for our deep understanding of the relationship among dimensionality, structure, and superconductivity phenomena in TMDs.

Characterizing the Piezosphere: The Effects of Decompression on Microbial Growth Dynamics.

The extent to which the full diversity of the subsurface microbiome can be captured via cultivation is likely hindered by the inevitable loss of cellular viability from decompression during sampling, enrichment, and isolation. Furthermore, the pressure tolerance of previously isolated strains that span surface and subsurface ecosystems can shed light into microbial activity and pressure adaptation in these transition zones. However, assessments of the effects of elevated pressure on the physiology of piezotolerant and piezosensitive species may be biased by high-pressure enrichment techniques. Here, we compared two high-pressure cultivation techniques—one that requires decompression of the whole cultures during sampling and one that employs the previously described isobaric PUSH devices—to explore the effects of repeated decompression during incubations performed to characterize isolates from deep environments. Two model sulfate-reducing prokaryotes were used to test the effects of decompression/repressurization cycles on growth rates, cell yields, and pressure tolerance. The mesophilic bacterium Desulfovibrio salexigens was cultivated from 0.1 to 50 MPa, and the hyperthermophilic archaeon Archaeoglobus fulgidus was tested from 0.1 to 98 MPa. For both cultivation methods, D. salexigens showed exponential growth up to 20 MPa, but faster growth rates were observed for isobaric cultivation. Furthermore, at 30 MPa minor growth was observed in D. salexigens cultures only for isobaric conditions. Isobaric conditions also extended exponential growth of A. fulgidus to 60 MPa, compared to 50 MPa when cultures were decompressed during subsampling. For both strains, growth rates and cell yields decreased with increasing pressures, and the most pronounced effects of decompression were observed at the higher end of the pressure ranges. These results highlight that repeated decompression can have a significant negative impact on cell viability, suggesting that decompression tolerance may depend on habitat depth. Furthermore, sampling, enrichment, and cultivation in isobaric devices is critical not only to explore the portion of the deep biosphere that is sensitive to decompression, but also to better characterize the pressure limits and growth characteristics of piezotolerant and piezosensitive species that span surface and subsurface ecosystems.

Achieving Higher Signal Response Than Splitless GC Injection by High-Pressure Headspace Sampling and Full Evaporation Technique

Achieving Higher Signal Response Than Splitless GC Injection by High-Pressure Headspace Sampling and Full Evaporation Technique

High-pressure polycrystalline thin-film synthesis and semiconducting property of platinum pernitride

A polycrystalline platinum pernitride (PtN2) thin-film was successfully synthesized via nitridation of a platinum thin-film deposited on α-Al2O3 substrate at the pressure of ∼50 GPa by using the laser-heated diamond anvil cell. The current–voltage characteristic and optical reflectance of the synthesized PtN2 thin-film were measured under ambient conditions. Combined with first-principles calculations, these experimental results have revealed that PtN2 exhibits semiconducting property with a bandgap of ∼2 eV. This high-pressure thin-film synthesis technique could also be applied for revealing the physical properties of other novel pernitrides synthesized under ultra-high pressure, which can offer new insights into the physical properties and functionality of the pernitrides and related nitrides.

Jet-Grouting Technology for Reinforcement Strata Disturbance After Sand Mining

During the construction of a bridge, due to the deep sand mining in the riverbed at the bridge site, a sand mining disturbance stratum is formed at the bridge site, and it has an impact on the construction quality of the pile group foundation. In this paper, in view of the special geological conditions caused by sand mining, the high-pressure jet grouting method was used to reinforce the disturbed stratum at the bridge site, and a scheme and key construction technology high-pressure rotary jet pile grouting to reinforce the disturbed stratum caused by sand mining is proposed. A three-dimensional finite element model of the pile group before and after reinforcement of the disturbed stratum by high-pressure jet grouting method is established. The distribution characteristics of the lateral displacement of the borehole wall in the disturbed stratum before and after reinforcement are compared and analysed. Application on an actual bridge proves that the high-pressure jet grouting method has a good reinforcement effect on the disturbed stratum, which effectively solves the phenomenon of hole expansion and pile casing falling in the construction process of the pile foundation caused by sand mining disturbance and improves the working performance and construction quality of the pile group foundation. The high-pressure jet grouting technique for reinforcement of disturbed stratum is proved to be effective in practice.

Industrially scalable exfoliated graphene nanoplatelets by high-pressure airless spray technique for high-performance supercapacitors

The significance of Graphene-based materials in various energy conversion and storage devices has been increasing due to their high surface area helps to enhance the multidimensional storage capability. Even though a significant amount of work has been done on graphene synthesis, there is still a need for an economical and environmentally friendly large-scale graphene synthesis method. This work demonstrates the large-scale production of high-quality Graphene Nanoplatelets (GnPs) by high-pressure spray exfoliation to develop high-performance supercapacitors. The high-pressure exfoliated GnPs were used to construct symmetric supercapacitors and studied their performance in organic and aqueous electrolytes. The pronounced rectangularity of cyclic voltammetry (CV) curves in both electrolytes indicates the charge storage is mainly by electrical double layer mechanisms. Retaining rectangularity at very high scan rates (>1000 mV/s) in both electrolytes signifies the excellent rate performance of high pressure exfoliated GnP based supercapacitors. The maximum specific capacitance of 26 F g−1 in the organic electrolyte and 86 F g−1 in the aqueous electrolyte was experimentally demonstrated, comparatively better than many other graphene-based device reports. The high capacitance and energy retention in the organic and aqueous electrolyte at very high current densities (>15 A g−1) indicate the potential usage during the demand surge power supply of exfoliated GnPs for the commercialization of graphene-based supercapacitors.

High-Pressure Technologies for the Recovery of Bioactive Molecules from Agro-Industrial Waste

Large amounts of food waste are produced each year. These residues require appropriate management to reduce their environmental impact and, at the same time, economic loss. However, this waste is still rich in compounds (e.g., colorants, antioxidants, polyphenols, fatty acids, vitamins, and proteins) that can find potential applications in food, pharmaceutical, and cosmetic industries. Conventional extraction techniques suffer some drawbacks when applied to the exploitation of food residues, including large amounts of polluting solvents, increased time of extraction, possible degradation of the active molecules during extraction, low yields, and reduced extraction selectivity. For these reasons, advanced extraction techniques have emerged in order to obtain efficient residue exploitation using more sustainable processes. In particular, performing extraction under high-pressure conditions, such as supercritical fluids and pressurized liquid extraction, offers several advantages for the extraction of bioactive molecules. These include the reduced use of toxic solvents, reduced extraction time, high selectivity, and the possibility of being applied in combination in a cascade of progressive extractions. In this review, an overview of high-pressure extraction techniques related to the recovery of high added value compounds from waste generated in food industries is presented and a critical discussion of the advantages and disadvantages of each process is reported. Furthermore, the possibility of combined multi-stage extractions, as well as economic and environmental aspects, are discussed in order to provide a complete overview of the topic.

A new transition metal diphosphide α-MoP2 synthesized by a high-temperature and high-pressure technique

Monoclinic α-MoP2, with the OsGe2-type structure (space group C2/m, Z = 4) and lattice parameters a = 8.7248(11) Å, b = 3.2322(4) Å, c = 7.4724(9)Å, and β = 119.263°, was synthesized under a pressure of 4~GPa at a temperature between 1100 °C and 1200 °C. The structure of α-MoP2 and its relationship to other transition metal diphosphides are discussed. Surprisingly, the ambient pressure phase orthorhombic β-MoP2 (space group Cmc21) is denser in structure than α-MoP2. Room-temperature high-pressure x-ray diffraction studies exclude the possibility of phase transition from β-MoP2 to α-MoP2, suggesting that α-MoP2 is a stable phase at ambient conditions; this is also supported by the total energy and phonon calculations.

Solution and Double Aging Treatments of Cold Sprayed Inconel 718 Coatings

In this study, Inconel 718 coatings were deposited by the high-pressure cold spray technique, and post-process solution and double aging treatments were conducted. The microstructures of the as-deposited and heat-treated IN718 were analyzed, and their mechanical properties were tested. It was found that the micro-dendritic structures in the original powder were severely elongated in the as-deposited IN718 coating due to plastic deformation during the cold spray process. After solution heat treatment, Nb, Mo, and Ti-rich segregations could be dissolved, transforming to MC carbide and a needle-like δ phase. It was found that the needle-like δ phase at the grain boundary had a pinning effect to slow down the grain growth. In addition, strengthening phases could be formed by aging treatments. The mechanical properties of the cold sprayed Inconel 718 could be improved by proper solution and aging heat treatments.

Giant Viscoelasticity near Mott Criticality in PbCrO_{3} with Large Lattice Anomalies.

Coupling of charge and lattice degrees of freedom in materials can produce intriguing electronic phenomena, such as conventional superconductivity where the electrons are mediated by lattice for creating supercurrent. The Mott transition, which is a source for many fascinating emergent behaviors, is originally thought to be driven solely by correlated electrons with an Ising criticality. Recent studies on the known Mott systems have shown that the lattice degree of freedom is also at play, giving rise to either Landau or unconventional criticality. However, the underlying coupling mechanism of charge and lattice degrees of freedom around the Mott critical end point remains elusive, leading to difficulties in understanding the associated Mott physics. Here, we report a study of Mott transition in cubic PbCrO_{3} by measuring the lattice parameter, using high-pressure x-ray diffraction techniques. The Mott criticality in this material is revealed with large lattice anomalies, which is governed by giant viscoelasticity that presumably results from a combination of lattice elasticity and electron viscosity. Because of the viscoelastic effect, the lattice of this material behaves peculiarly near the critical end point, inconsistent with any existing university classes. We argue that the viscoelasticity may play as a hidden degree of freedom behind the Mott criticality.

Polylactic acid nanoparticles for co-delivery of dinotefuran and avermectin against pear tree pests with improved effective period and enhanced bioactivity

Pesticide compounding technology for disease and pest control emerges as an effective way to increase the effectiveness of pesticides while reducing pesticides resistance. Nanomaterials and encapsulation technology have offered a new insight into preparing efficient pesticide formulations, especially constructing a co-delivery nanoparticle for synergistic pesticides. In this study, a dinotefuran/avermectin co-delivery nanoparticles (DACNPs) against pear tree pests with polylactic acid (PLA) as the wall material were constructed by double-emulsion method combined with high-pressure homogenization technique. The drug content of the DACNPs was 39.1% with an average size of 245.7 ± 4.2 nm and the mean polymer dispersity index (PDI) value was 0.123. The DACNPs showed high foliar retention and good spread performance on target leaves due to the nanoscale effect. The obtained DACNPs showed a better control effect on Grapholitha molesta Busck and Psylla chinensis Yang et Li compared with the commercial formulations, which could significantly prolong the effective duration and enhance the bioactivity with lower amounts and application frequency of pesticides. This study may provide new insights into developing novel pesticide formulations to improve the utilization rate of pesticides, reduce environmental pollution and minimize the cost of farming.

High-Pressure Synthesis of Superconducting Sn3S4 Using a Diamond Anvil Cell with a Boron-Doped Diamond Heater.

High-pressure techniques open exploration of functional materials in broad research fields. An established diamond anvil cell with a boron-doped diamond heater and transport measurement terminals has performed the high-pressure synthesis of a cubic Sn3S4 superconductor. X-ray diffraction and Raman spectroscopy reveal that the Sn3S4 phase is stable in the pressure range of P > 5 GPa in a decompression process. Transport measurement terminals in the diamond anvil cell detect a metallic nature and superconductivity in the synthesized Sn3S4 with a maximum onset transition temperature (Tconset) of 13.3 K at 5.6 GPa. The observed pressure-Tc relationship is consistent with that from the first-principles calculation. The observation of superconductivity in Sn3S4 opens further materials exploration under high-temperature and -pressure conditions.