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1.
Nat Commun ; 12(1): 5018, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34465789

RESUMO

Chocolate manufacture includes a complex tempering procedure to direct the crystallization of cocoa butter towards the formation of fat crystal networks with specific polymorphism, nano- and microstructure, melting behavior, surface gloss and mechanical properties. Here we investigate the effects of adding various minor non-triglyceride lipidic components to refined cocoa butter and chocolate on their physical properties. We discover that addition of saturated phosphatidylcholine and phosphatidylethanolamine to neutralized and bleached cocoa butter or molten and recrystallized commercial chocolate at 0.1% (w/w) levels, followed by rapid cooling to 20 °C in the absence of shear, accelerates crystallization, stabilizes the desirable Form V polymorph and induces the formation of chocolate with an optimal microstructure, surface gloss and mechanical strength. Final chocolate structure and properties are comparable to those of a commercial tempered chocolate. Minor lipidic component addition represents an effective way to engineer chocolate material properties at different length scales, thus simplifying the entire tempering process.


Assuntos
Chocolate/análise , Gorduras na Dieta/análise , Aditivos Alimentares/química , Lipídeos/química , Cacau/química , Cristalização , Manipulação de Alimentos
2.
Mater Sci Eng C Mater Biol Appl ; 128: 112338, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474889

RESUMO

The nucleation, growth and aggregation of calcium oxalate (CaOx) crystals and the oxidative damage of renal tubular epithelial cells are the key factors to induce kidney stones. In this study, degraded Porphyra yezoensis polysaccharide (PYP0) with 14.14% sulfate group (-OSO3-) content was modified via the sulfur trioxide-pyridine method to obtain three kinds of sulfated P. yezoensis polysaccharides (PYPs), namely, PYPS1, PYPS2, and PYPS3, with -OSO3- group contents of 17.11%, 20.28%, and 27.14% respectively. Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR analyses showed that the -OSO3- groups replaced the hydroxyl groups at the C2, C4, and C6 positions on (1 â†’ 3)-linked ß-D-galactose, the basic structural skeleton unit of PYP0. The antioxidant activity of the PYPSs increased after sulfation, and their scavenging capacity for OH and DPPH free radicals was enhanced with the increase in their -OSO3- group content. Calcium oxalate (CaOx) crystal growth experiments showed that sulfated PYPs promoted the conversion of the thermodynamically stable and sharp CaOx monohydrate (COM) crystals into the thermodynamically unstable and round CaOx dihydrate crystals. With the increase in the -OSO3- group content of the polysaccharides, the concentration of soluble Ca2+ ions in the supernatant increased and the amount of CaOx precipitate decreased. PYPs were nontoxic to human kidney proximal tubular epithelial cells (HK-2) and could protect HK-2 from oxidative damage caused by nano-COM and reduce the level of reactive oxygen species in cells. PYPS3, which had the highest degree of sulfation, had the best protective capability. The results of this work showed that sulfation improved the biological activity of PYPs. This study could provide inspiration for the development of new drugs for the prevention and treatment of kidney stones.


Assuntos
Oxalato de Cálcio , Porphyra , Antioxidantes/farmacologia , Cristalização , Humanos , Polissacarídeos/farmacologia , Sulfatos
3.
J Phys Chem Lett ; 12(34): 8416-8422, 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34436909

RESUMO

Polyproline II (pPII) is a left-handed 31-helix conformation, which has been observed to be the most abundant secondary structure in unfolded peptides and proteins compared to α-helix and ß-sheet. Although pPII has been reported as the most stable conformation for several unfolded short chain peptides in aqueous solution, it is rarely observed in their solid state. Here, we show for the first time a glycine homopeptide (gly-gly-gly) adopting the pPII conformation in its crystalline dihydrate structure. The single crystal X-ray structure with molecular dynamic simulation suggests that a network of water and the charged carboxylate group is critical in stabilizing the pPII conformation in solid state, offering an insight into the structures of unfolded regions of proteins and the role of water in peptide crystallization.


Assuntos
Oligopeptídeos/química , Peptídeos/química , Água/química , Cristalização , Conformação Molecular
4.
Nat Commun ; 12(1): 4966, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404784

RESUMO

Although chirality is an ever-present characteristic in biology and some artificial molecules, controlling the chirality and demystifying the chirality origin of complex assemblies remain challenging. Herein, we report two homochiral Ag14 nanoclusters with inherent chirality originated from identical rotation of six square faces on a Ag8 cube driven by intra-cluster π···π stacking interaction between pntp- (Hpntp = p-nitrothiophenol) ligands. The spontaneous resolution of the racemic (SD/rac-Ag14a) to homochiral nanoclusters (SD/L-Ag14 and SD/R-Ag14) can be realized by re-crystallizing SD/rac-Ag14a in acetonitrile, which promotes the homochiral crystallization in solid state by forming C-H···O/N hydrogen bonds with nitro oxygen atoms in pntp- or aromatic hydrogen atoms in dpph (dpph = 1,6-bis(diphenylphosphino)hexane) on Ag14 nanocluster. This work not only provides strategic guidance for the syntheses of chiral silver nanoclusters in an all-achiral environment, but also deciphers the origin of chirality at molecular level by identifying the special effects of intra- and inter-cluster supramolecular interactions.


Assuntos
Cristalização , Compostos Organometálicos/química , Fenômenos Físicos , Prata/química , Acetonitrilas/química , Cristalografia por Raios X , Hexanos , Hidrogênio , Ligação de Hidrogênio , Modelos Moleculares , Conformação Molecular , Oxigênio , Rotação
5.
Food Res Int ; 147: 110557, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34399534

RESUMO

The crystallisation behaviour of milk fat plays an important role in the functionality and sensory properties of fat-rich dairy products. In this study, we investigated the impact of tempering to 25 °C on the viscoelastic properties, particle size and thermal behaviour of 20% w/w unprocessed and homogenised creams prepared from bovine milk. The crystallisation properties were examined by synchrotron X-ray diffraction (XRD) at small (SAXS) and wide angle (WAXS) and differential scanning calorimetry (DSC). Oscillation rheology was performed to characterise the cream's viscoelastic properties. Homogenisation (35 MPa) reduced the average droplet size from 4.4 to 1.3 µm. After 24 h storage at 4 °C, milk fat structures showed triacylglycerol (TAG) 2L and 3L(001, 002, 003, 005) lamellar stacking orders associated predominantly with the α and ß' polymorphic forms. Tempering to 25 °C induced the complete melting of the 3L crystals and led to an irreversible loss in the elastic modulus (G') and a reduction in the viscous modulus (G'') once returned to refrigerated conditions, due to changes in the particle-particle interactions and structure of the reformed milk fat crystals. The results demonstrate that crystallisation behaviour of milk fat is influenced by droplet size and the rearrangement of triacylglycerol (TAG) upon tempering, and lead to changes in the viscoelastic behaviour of dairy products containing a high level of milk fat.


Assuntos
Leite , Animais , Bovinos , Cristalização , Espalhamento a Baixo Ângulo , Temperatura , Difração de Raios X
6.
Molecules ; 26(16)2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34443346

RESUMO

A temperature dependence of saturated vapor pressure of isavuconazole (IVZ), an antimycotic drug, was found by using the method of inert gas-carrier transfer and the thermodynamic functions of sublimation were calculated at a temperature of 298.15 K. The value of the compound standard molar enthalpy of sublimation was found to be 138.1 ± 0.5 kJ·mol-1. The IVZ thermophysical properties-melting point and enthalpy-equaled 302.7 K and 29.9 kJ mol-1, respectively. The isothermal saturation method was used to determine the drug solubility in seven pharmaceutically relevant solvents within the temperature range from 293.15 to 313.15 K. The IVZ solubility in the studied solvents increased in the following order: buffer pH 7.4, buffer pH 2.0, buffer pH 1.2, hexane, 1-octanol, 1-propanol, ethanol. Depending on the solvent chemical nature, the compound solubility varied from 6.7 × 10-6 to 0.3 mol·L-1. The Hansen s approach was used for evaluating and analyzing the solubility data of drug. The results show that this model well-described intermolecular interactions in the solutions studied. It was established that in comparison with the van't Hoff model, the modified Apelblat one ensured the best correlation with the experimental solubility data of the studied drug. The activity coefficients at infinite dilution and dissolution excess thermodynamic functions of IVZ were calculated in each of the solvents. Temperature dependences of the compound partition coefficients were obtained in a binary 1-octanol/buffer pH 7.4 system and the transfer thermodynamic functions were calculated. The drug distribution from the aqueous solution to the organic medium was found to be spontaneous and entropy-driven.


Assuntos
Nitrilas/química , Piridinas/química , Temperatura , Triazóis/química , 1-Octanol/química , Varredura Diferencial de Calorimetria , Cristalização , Solubilidade , Solventes/química , Volatilização , Água/química
7.
Molecules ; 26(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361739

RESUMO

We developed an alternative whipping cream fat using shea butter but with low saturation. Enriched stearic-oleic-stearic (SOS) solid fat was obtained from shea butter via solvent fractionation. Acyl migration reactant, which mainly contains asymmetric SSO triacylglycerol (TAG), was prepared through enzymatic acyl migration to obtain the creaming quality derived from the ß'-crystal form. Through enzymatic acyl migration, we obtained a 3.4-fold higher content of saturated-saturated-unsaturated (SSU) TAG than saturated-unsaturated-saturated (SUS) TAG. The acyl migration reactant was refined to obtain refined acyl migration reactant (RAMR). An alternative fat product was prepared by blending RAMR and hydrogenated palm kernel oil (HPKO) at a ratio of 4:6 (w/w). The melting points, solid fat index (SFI), and melting curves of the alternative products were similar to those of commercial whipping cream fat. The alternative fat had a content of total unsaturated fatty acids 20% higher than that of HPKO. The atherogenic index (AI) of alternative fat was 3.61, much lower than those of whipping cream fat (14.59) and HPKO (1220.3), because of its low atherogenic fatty acid content and high total unsaturated fatty acids. The polymorphic crystal form determined by X-ray diffraction spectroscopy showed that the ß'-crystal form was predominant. Therefore, the alternative fat is comparable with whipping cream that requires creaming quality, and has a reduced saturated fat content.


Assuntos
Gorduras na Dieta/análise , Ácidos Graxos Insaturados/química , Tecnologia de Alimentos/métodos , Ácidos Oleicos/química , Óleos Vegetais/química , Fracionamento Químico , Cristalização , Ácidos Graxos Insaturados/análise , Humanos , Ácido Oleico/análise , Ácido Oleico/química , Ácidos Oleicos/análise , Óleo de Palmeira/análise , Óleo de Palmeira/química , Óleos Vegetais/análise , Ácidos Esteáricos/análise , Ácidos Esteáricos/química , Triglicerídeos/análise , Triglicerídeos/química
8.
Molecules ; 26(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361760

RESUMO

Self-assembly is the most powerful force for creating ordered supramolecular architectures from simple components under mild conditions. π···π stacking interactions have been widely explored in modern supramolecular chemistry as an attractive reversible noncovalent tool for the nondestructive fabrication of materials for different applications. Here, we report on the self-assembly of cytidine 5'-monophosphate (CMP) nucleotide and copper metal ions for the preparation of a rare nanoporous supramolecular metal-organic framework in water. π···π stacking interactions involving the aromatic groups of the ancillary 2,2'-bipyridine (bipy) ligands drive the self-assemblies of hexameric pseudo-amphiphilic [Cu6(bipy)6(CMP)2(µ-O)Br4]2+ units. Owing to the supramolecular geometric matching between the aromatic tails, a nanoporous crystalline phase with hydrophobic and hydrophilic chiral pores of 1.2 and 0.8 nanometers, respectively, was successfully synthesized. The encoded chiral information, contained on the enantiopure building blocks, is transferred to the final supramolecular structure, assembled in the very unusual topology 8T6. These kinds of materials, owing to chiral channels with chiral active sites from ribose moieties, where the enantioselective recognition can occur, are, in principle, good candidates to carry out efficient separation of enantiomers, better than traditional inorganic and organic porous materials.


Assuntos
2,2'-Dipiridil/química , Cobre/química , Citidina Monofosfato/química , Estruturas Metalorgânicas/síntese química , Cristalização , Cristalografia por Raios X , Interações Hidrofóbicas e Hidrofílicas , Estruturas Metalorgânicas/química , Estrutura Molecular , Porosidade , Soluções , Estereoisomerismo
9.
Eur J Pharm Sci ; 166: 105981, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34428483

RESUMO

PURPOSE: Dexamethasone (Dex) is a widely used drug for the treatment of inflammatory and autoimmune conditions, however, long-term systemic use of Dex is associated with serious adverse effects. The objective of the present study was to develop an implantable device to avoid side effects and realize a controlled release of Dex at the implant site. METHODS: Hydrophobic Dex was incorporated into biodegradable polyesters derived from PCL and Pluronic® L64 (PCL-Pluronic L64-PCL, PCLC) by hot-melt extrusion (HME) method to prepare Dex/PCLC implantable devices. Drug loading and encapsulation efficiency, a series of physicochemical properties, and in vivo features of the implants were studied. RESULTS: The maximum value of the drug loading and encapsulation efficiency for the Dex/PCLC implants were up to 47% and 94%, respectively. Incorporation of Dex resulted in accelerated crystallization of PCLC, decreased the wettability, increased contact angles and viscosity, and accelerated Dex release rate and degradation rate from the implants in vivo. Moreover, Dex/PCLC implants showed excellent biocompatibility. Furthermore, the inflammatory response to the Dex/PCLC implants was less severe than that to the positive control group. CONCLUSION: All these results suggested that Dex/PCLC implants might be a safe and controlled local drug delivery system with excellent inflammatory response suppression effect.


Assuntos
Implantes Absorvíveis , Tecnologia de Extrusão por Fusão a Quente , Cristalização , Dexametasona , Sistemas de Liberação de Medicamentos , Implantes de Medicamento , Poliésteres
10.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445122

RESUMO

Seven inorganic salts containing N-phenylbiguanide as a prospective organic molecular carrier of nonlinear optical properties were prepared and studied within our research of novel hydrogen-bonded materials for nonlinear optics (NLO). All seven salts, namely N-phenylbiguanidium(1+) nitrate (C2/c), N-phenylbiguanidium(1+) perchlorate (P-1), N-phenylbiguanidium(1+) hydrogen carbonate (P21/c), bis(N-phenylbiguanidium(1+)) sulfate (C2), bis(N-phenylbiguanidium(1+)) hydrogen phosphate sesquihydrate (P-1), bis(N-phenylbiguanidium(1+)) phosphite (P21), and bis(N-phenylbiguanidium(1+)) phosphite dihydrate (P21/n), were characterised by X-ray diffraction (powder and single-crystal X-ray diffraction) and by vibrational spectroscopy (FTIR and Raman). Two salts with non-centrosymmetric crystal structures-bis(N-phenylbiguanidium(1+)) sulfate and bis(N-phenylbiguanidium(1+)) phosphite-were further studied to examine their linear and nonlinear optical properties using experimental and computational methods. As a highly SHG-efficient and phase-matchable material transparent down to 320 nm and thermally stable to 483 K, bis(N-phenylbiguanidium(1+)) sulfate is a promising novel candidate for NLO.


Assuntos
Sais/química , Cristalização/métodos , Cristalografia por Raios X/métodos , Óptica e Fotônica/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Espectral Raman/métodos , Termogravimetria/métodos , Difração de Raios X/métodos
11.
Chem Biol Interact ; 347: 109605, 2021 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-34333021

RESUMO

Cell injury is a necessary and critical event during CaOx kidney stone formation. Sirt1 exerts a number of pleiotropic effects, protecting against renal cell injury. This study aims to explore the relationship between Sirt1 and CaOx kidney stone formation and the underlying mechanism. Sirt1 expression in renal tissues or HK-2 cells was detected by Western blot, immunohistochemistry and immunofluorescence. Apoptosis in renal tissues was examined by TUNEL staining. Renal pathological changes and the crystals deposition were detected by hematoxylin-eosin and Von Kossa staining. Crystal-cell adhesion and cell injury in HK-2 cells were assessed by atomic absorption spectrometry and flow cytometry, respectively. Sirt1 expression in nephrolithiasis patients was downregulated and the level of apoptosis was increased. Further study found that Sirt1 expression was decreased in both in vivo and in vitro models. Interestingly, the levels of cell injury were elevated in vivo and in vitro models. Suppressing Sirt1 expression promoted COM-induced crystal-cell adhesion and exacerbated cell injury. In contrast, increasing the expression of Sirt1 by lentivirus transfection in vitro and resveratrol administration in vivo, alleviated crystal deposition and cell damage. Our findings suggest that Sirt1 could inhibit kidney stone formation, at least in part, through attenuating CaOx -induced cell injury.


Assuntos
Oxalato de Cálcio/efeitos adversos , Cálculos Renais/metabolismo , Sirtuína 1/metabolismo , Idoso , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Oxalato de Cálcio/química , Oxalato de Cálcio/farmacologia , Adesão Celular/efeitos dos fármacos , Adesão Celular/fisiologia , Linhagem Celular , Cristalização , Feminino , Inativação Gênica , Glioxilatos , Humanos , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Cálculos Renais/induzido quimicamente , Cálculos Renais/tratamento farmacológico , Cálculos Renais/patologia , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Necrose/induzido quimicamente , Necrose/metabolismo , Resveratrol/uso terapêutico , Sirtuína 1/genética
12.
Science ; 373(6552): 337-342, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34437153

RESUMO

Piezoelectric biomaterials are intrinsically suitable for coupling mechanical and electrical energy in biological systems to achieve in vivo real-time sensing, actuation, and electricity generation. However, the inability to synthesize and align the piezoelectric phase at a large scale remains a roadblock toward practical applications. We present a wafer-scale approach to creating piezoelectric biomaterial thin films based on γ-glycine crystals. The thin film has a sandwich structure, where a crystalline glycine layer self-assembles and automatically aligns between two polyvinyl alcohol (PVA) thin films. The heterostructured glycine-PVA films exhibit piezoelectric coefficients of 5.3 picocoulombs per newton or 157.5 × 10-3 volt meters per newton and nearly an order of magnitude enhancement of the mechanical flexibility compared with pure glycine crystals. With its natural compatibility and degradability in physiological environments, glycine-PVA films may enable the development of transient implantable electromechanical devices.


Assuntos
Materiais Biocompatíveis/química , Eletricidade , Glicina/química , Álcool de Polivinil/química , Animais , Sobrevivência Celular , Células Cultivadas , Cristalização , Teoria da Densidade Funcional , Elasticidade , Humanos , Ligação de Hidrogênio , Próteses e Implantes , Ratos , Ratos Sprague-Dawley , Estresse Mecânico
13.
Molecules ; 26(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34443617

RESUMO

The present study is focused on the effect of biofilm medium chemistry on oxalate crystallization and contributes to the study of the patterns of microbial biomineralization and the development of nature-like technologies, using the metabolism of microscopic fungi. Calcium oxalates (weddellite and whewellite in different ratios) were synthesized by chemical precipitation in a weakly acidic environment (pH = 4-6), as is typical for the stationary phase of micromycetes growth, with a ratio of Ca2+/C2O42- = 4.0-5.5, at room temperature. Additives, which are common for biofilms on the surface of stone in an urban environment (citric, malic, succinic and fumaric acids; and K+, Mg2+, Fe3+, Sr2+, SO42+, PO43+ and CO32+ ions), were added to the solutions. The resulting precipitates were studied via X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). It was revealed that organic acids, excreted by micromicetes, and some environmental ions, as well as their combinations, significantly affect the weddellite/whewellite ratio and the morphology of their phases (including the appearance of tetragonal prism faces of weddellite). The strongest unique effect leading to intensive crystallization of weddellite was only caused by the presence of citric acid additive in the medium. Minor changes in the composition of the additive components can lead to significant changes in the weddellite/whewellite ratio. The effect of the combination of additives on this ratio does not obey the law of additivity. The content of weddellite in the systems containing a representative set of both organic acids and environmental ions is ~20 wt%, which is in good agreement with natural systems.


Assuntos
Biofilmes/crescimento & desenvolvimento , Oxalato de Cálcio/química , Cristalização , Concentração de Íons de Hidrogênio
14.
ACS Appl Mater Interfaces ; 13(33): 39142-39156, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34433244

RESUMO

The reconstruction of the intra/interfibrillar mineralized collagen microstructure is extremely important in biomaterial science and regeneration medicine. However, certain problems, such as low efficiency and long period of mineralization, are apparent, and the mechanism of interfibrillar mineralization is often neglected in the present literature. Thus, we propose a novel model of biomimetic collagen mineralization that uses molecules with the dual function of cross-linking collagen and regulating collagen mineralization to construct the intrafibrillar and interfibrillar collagen mineralization of the structure of mineralized collagen hard tissues. In the present study completed in vitro, N-2-(3,4-dihydroxyphenyl) acrylamide (DAA) is used to bind and cross-link collagen molecules and further stabilize the self-assembled collagen fibers. The DAA-collagen complex provides more affinity with calcium and phosphate ions, which can reduce the calcium phosphate/collagen interfacial energy to promote hydroxyapatite (HA) nucleation and accelerate the rate of collagen fiber mineralization. Besides inducing intrafibrillar mineralization, the DAA-collagen complex mineralization template can realize interfibrillar mineralization with the c-axis of the HA crystal on the surface of collagen fibers and between fibers that are parallel to the long axis of collagen fibers. The DAA-collagen complex, as a new type of mineralization template, may provide a new collagen mineralization strategy to produce a mineralized scaffold material for tissue engineering or develop bone-like materials.


Assuntos
Acrilamida/química , Materiais Biomiméticos/química , Colágeno/química , Dopamina/química , Osso e Ossos , Cálcio/química , Cálcio/metabolismo , Fosfatos de Cálcio/química , Reagentes para Ligações Cruzadas/química , Cristalização , Durapatita/química , Durapatita/metabolismo , Matriz Extracelular/metabolismo , Humanos , Simulação de Dinâmica Molecular , Polimerização , Medicina Regenerativa , Propriedades de Superfície , Engenharia Tecidual
15.
Int J Mol Sci ; 22(13)2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34206862

RESUMO

We report an ultra-high vacuum low-temperature scanning tunneling microscopy (STM) study of the C60 monolayer grown on Cd(0001). Individual C60 molecules adsorbed on Cd(0001) may exhibit a bright or dim contrast in STM images. When deposited at low temperatures close to 100 K, C60 thin films present a curved structure to release strain due to dominant molecule-substrate interactions. Moreover, edge dislocation appears when two different wavy structures encounter each other, which has seldomly been observed in molecular self-assembly. When growth temperature rose, we found two forms of symmetric kagome lattice superstructures, 2 × 2 and 4 × 4, at room temperature (RT) and 310 K, respectively. The results provide new insight into the growth behavior of C60 films.


Assuntos
Microscopia de Tunelamento/métodos , Compostos Organometálicos/química , Cristalização , Polimerização , Estresse Mecânico , Temperatura , Vácuo
16.
Int J Mol Sci ; 22(13)2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34206936

RESUMO

The cascaded dual-chirped optical parametric amplification (DC-OPA) is presented for efficient generation of few-cycle infrared (IR) laser pulses. The input pulses are strategically chirped to optimize the phase-matching bandwidth in each nonlinear crystal, and four regions of the signal spectrum are amplified in cascaded crystals with different cutting angles, enabling flexible manipulation of the output spectrum. Broadband gain and high conversion efficiency are simultaneously achieved owing to the cascaded-crystal arrangement, the signal pulse duration of 4.2 cycles is obtained with 11.7-mJ pulse energy, corresponding to a conversion efficiency of 39.0%. The proposed scheme offers a robust and simple approach to pushing the phase-matching bandwidth limits introduced by the nonlinear crystal, which manifests great prospect in various researches involving ultrafast optics and strong-field physics.


Assuntos
Raios Infravermelhos , Lasers , Cristalização , Óptica e Fotônica/métodos
17.
Ann Palliat Med ; 10(6): 7121-7125, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34237991

RESUMO

Bronchobiliary fistula (BBF) refers to the abnormal traffic between the biliary tract and the bronchus. The condition is very rare and usually develops secondary to liver echinococcosis or amebiasis, liver abscess, trauma, biliary obstruction, or tumors. BBF has a high mortality rate and currently, there are no accurate and effective diagnostic methods. This study reports the diagnosis and treatment of two patients with BBF which were confirmed by detecting bilirubin crystallization in the sputum. The first patient was a 45-year-old woman admitted to the hospital with "recurrent cough and lung infection". She had a history of multiple biliary tract surgeries and bilirubin crystallization was detected in bronchoalveolar lavage fluid (BALF) upon examination. Computed tomography (CT) imaging and magnetic resonance cholangiopancreatography (MRCP), together with clinical features, confirmed a diagnosis of BBF. The second patient was a 53-year-old woman admitted to the hospital with coughing and bile-like sputum. She had a history of cholangiocarcinoma surgery and bilirubin crystallization was detected in the cytomorphological BALF examination. Endoscopic retrograde cholangiopancreatography (ERCP) combined with clinical features confirmed a diagnosis of BBF. Both patients recovered after treatment and were discharged from the hospital. The clinical diagnosis of BBF largely relies upon imaging combined with clinical standards, and BALF examinations are rarely performed. This current investigation retrospectively analyzed the diagnosis and treatment of two cases of BBF, and demonstrated that bilirubin crystallization in the BALF may be an important diagnostic indicator for BBF.


Assuntos
Fístula Biliar , Bilirrubina , Fístula Biliar/diagnóstico , Líquido da Lavagem Broncoalveolar , Cristalização , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos
18.
Chemistry ; 27(49): 12521-12525, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34236738

RESUMO

Photochemical activation is proposed as a general method for controlling the crystallization of sparingly soluble carbonates in space and time. The photogeneration of carbonate in an alkaline environment is achieved upon photo-decarboxylation of an organic precursor by using a conventional 365 nm UV LED. Local irradiation was conducted focusing the LED light on a 300 µm radius spot on a closed glass crystallization cell. The precursor solution was optimized to avoid the precipitation of the photoreaction organic byproducts and prevent photo-induced pH changes to achieve the formation of calcium carbonate only in the corresponding irradiated area. The crystallization was monitored in real-time by time-lapse imaging. The method is also shown to work in gels. Similarly, it was also shown to photo-activate locally the formation of barium carbonate biomorphs. In the last case, the morphology of these biomimetic structures was tuned by changing the irradiation intensity.


Assuntos
Carbonato de Cálcio , Carbonatos , Bário , Cristalização
19.
Ultrason Sonochem ; 77: 105675, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34298309

RESUMO

In this paper, the ultrasound-assisted solvent-mediated polymorphic transformation of theophylline was explored in detail. The induction time and reconstruction time were significantly decreased by ultrasound, thereby decreasing the total transformation time and promoting the transformation process. The ultrasound-promoted efficiency of nucleation was different in three alcoholic solvents, which was difficult to explain by traditional kinetic effects. To resolve the above confusion, binding energies calculated by Density Functional Theory were applied to explore the relationship between the ultrasound-promoted efficiency of nucleation and solute-solvent interactions. Then, a possible molecular self-assembly nucleation pathway affected by ultrasound was proposed: the ultrasound could change and magnify the crucial effect of the specific sites of solute-solvent interactions in the nucleation process. Finally, the transformation kinetics with different effective ultrasonic energies was quantitatively analyzed by Avrami-Erofeev model, indicating that the dissolution element in the rate-limiting step was gradually eliminated by higher ultrasonic energy. Fortunately, the elusive crystal form V could be easily obtained by the ultrasound-assisted polymorph transformation. This proved to be a robust method to produce high purity form V of theophylline. The outcome of this study demonstrated that the proper ultrasonic irradiation had the potential to produce specific polymorphs selectively.


Assuntos
Teofilina/química , Ondas Ultrassônicas , Cristalização , Cinética , Modelos Moleculares , Conformação Molecular , Solubilidade , Solventes/química
20.
Analyst ; 146(15): 4883-4894, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34241601

RESUMO

The processing of healthy foods remains a challenge and any technology with the ability to tailor the physical properties of new materials is in demand. High-intensity ultrasound (HIU) has been identified as a useful processing technique for such activities particularly for edible lipids. HIU has been known to alter the crystallisation kinetics and in turn the resultant physicochemical properties for specific food applications. The role of cavitation dynamics during treatment of oils with HIU is of interest, with the knowledge gained allowing for insight into the complex and still undefined mechanism of action. To this end, the crystallisation kinetics of an edible lipid were investigated in the presence of several distinctly different cavitation conditions. Several cavitation clusters, including a bifurcated streamer (BiS), located on the surface of a piston-like emitter (PLE) were studied, each generated by a specific ultrasonic power level. Only samples crystallised at a low supercooling (ΔTSC) value display significant differences in induction time for each of the selected HIU powers, at least 5 minutes earlier than without exposure to HIU. Substantially better energy efficiencies were seen for the BiS regime (ΔTSC = 5 °C) which coincided with maximal crystal growth rates. An increase in melting enthalpy and elastic modulus is reported in the presence of HIU for all crystallisation temperatures, this effect is larger overall with increasing ultrasonic power. In addition, sonicated samples in the presence of the BiS event were composed of fewer smaller crystals compared to higher HIU powers after 60 minutes at 30 °C. Bubble dynamics recorded during a 10 s sonication period exhibited a greater acoustic attenuation effect for the highest ultrasonic power (75 W). The results suggest that the dynamics of the cluster and the presence of the BiS event are important in terms of energy efficiency and the physical properties of the crystallised lipid material.


Assuntos
Lipídeos , Óleos Vegetais , Cristalização , Cinética , Temperatura
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