69 research outputs found
Massive particles' Hawking radiation via tunneling from the G.H Dilaton black hole
In the past, Hawking radiation was viewed as a tunneling process and the
barrier was just created by the outgoing particle itself. In this paper,
Parikh's recent work is extended to the case of massive particles' tunneling.
We investigate the behavior of the tunneling massive particles from a
particular black hole solution-G.H Dilaton black hole which is obtained from
the string theory, and calculate the emission rate at which massive particles
tunnel across the event horizon. We obtain that the result is also consistent
with an underlying unitary theory. Furthermore, the result takes the same
functional form as that of massless particles.Comment: 6 pages, no figure, revtex
Massive uncharged and charged particles' tunneling from the Horowitz-Strominger Dilaton black hole
Originally, Parikh and Wilczek's work is only suitable for the massless
particles' tunneling. But their work has been further extended to the cases of
massive uncharged and charged particles' tunneling recently. In this paper, as
a particular black hole solution, we apply this extended method to reconsider
the tunneling effect of the H.S Dilaton black hole. We investigate the behavior
of both massive uncharged and charged particles, and respectively calculate the
emission rate at the event horizon. Our result shows that their emission rates
are also consistent with the unitary theory. Moreover, comparing with the case
of massless particles' tunneling, we find that this conclusion is independent
of the kind of particles. And it is probably caused by the underlying
relationship between this method and the laws of black hole thermodynamics.Comment: 6 pages, no figure, revtex 4, accepted by Int. J. Mod. Phys
Protein/polysaccharide intramolecular electrostatic complex as superior food-grade foaming agent
High-performance foaming agents are widely required in the food industry. In this study, the relationship between electrostatic interaction of whey protein isolate (WPI)/alginate (ALG) and the resultant foaming properties were investigated systematically. The phase diagram of WPI/ALG was established in terms of protein/polysaccharide mixing ratio (r) and pH. The results show that the foaming capacity of WPI/ALG complexes is almost the same across different regions of the phase
diagram, while the foam stability varies significantly. At pHs 7.0 and 0.5 where no electrostatic complexation occurs, the foam stability is found to decrease monotonically with decreasing r. At pH 4.0 and particular mixing ratios, i.e., r = 1 and 2, intramolecular soluble complexes are formed and the particular WPI/ALG complexes yield the best foam stability, as compared to other electrostatic complexes or individual components. The half-life (t1/2) of the foams stabilized by the intramolecular electrostatic complexes is as long as 4000 s at a very low WPI/ALG concentration of 0.1% w/w. The foaming properties are in line with the foam viscosity, interfacial adsorption behavior and
microstructures of the complexes observed at the air-water interface. This demonstrates that the protein/polysaccharide intramolecular electrostatic complex, more specifically at the stoichiometry, could potentially act as a superior foaming agent in the food industry
Effect of arabinogalactan protein complex content on emulsification performance of gum arabic
The emulsification properties of the standard (STD), matured (EM2 and EM10) and fractionated gum arabic samples via phase separation induced molecular fractionation were investigated to find out how the content of arabinogalactan protein (AGP) complex affects the resulting emulsion properties. Phase separation and the accompanying molecular fractionation were induced by mixing with different hydrocolloids including hyaluronan (HA), carboxymethyl cellulose (CMC), and maltodextrin (MD). Increase of AGP content from 11 to 28% resulted in the formation of emulsions with relatively smaller droplet sizes and better stability. Further increase in the AGP content to 41% resulted in the formation of emulsions with larger droplets. In spite of the larger droplets sizes, these emulsions were extremely stable. In addition, the emulsions prepared with GA higher AGP content better stability in the presence of ethanol. The results indicate that AGP content plays a vital role in emulsion stability and droplet size
Interfacial and emulsifying properties of the electrostatic complex of β-lactoglobulin fibril and gum Arabic (Acacia Seyal)
Formation, interfacial and emulsifying properties of the electrostatic complex of β-lactoglobulin fibril (BLGF) and gum Arabic Acacia Seyal (AS) were investigated. Necklace-like soluble complex could be formed at pH 3.5, and its charge and interfacial properties depended on the BLGF content. With appropriate amount of BLGF (< 9.09 wt.%), the formed complex possessed a good dispersibility and surface activity. When excessive BLGF (9.09∼50 wt.%) existed, surface charge of the complex was gradually neutralized and aggregation occurred. Homogeneous oil-in-water emulsions could be stabilized by the complex and the droplet size decreased with increasing BLGF content. Higher content of BLGF (9.09∼50 wt.%) was detrimental for emulsification due to the aggregation of complex, and the formed emulsion tended to flocculate. Compared with AS, the complex formed emulsions were much more stable against heating (90 ℃, 30 min) and salting (200 mM NaCl) environments, and the emulsions were stable during long-term storage (46 days).
Proposed mechanisms for the adsorption of BLGF/AS complex at the oil-water interface. Pure AS (i) could adsorb at the oil-water interface but formed a loose film due to its poor surface activity and insufficient adsorption amount. With addition of a small amount of fibrils (ii), soluble electrostatic complexes are formed and they can be adsorbed at the interface to formed a dense viscoelastic film due to the surface activity of the BLGF. With a higher content of fibrils (iii), surface charge of the complex tended to be neutralized, causing the aggregation. Because the presence of protein fibrils, they could also adsorb at the oil-water interface to produce a viscoelastic film. However, with a bigger size and irregular shape, the aggregates were difficult to array at the interface as densely as the soluble complex
Formation, influencing factors, and applications of internal channels in starch: A review
Starch, a natural polymer, has a complex internal structure. Some starches, such as corn and wheat starches, have well-developed surface pores and internal channels. These channel structures are considered crucial in connecting surface stomata and internal cavities and have adequate space for loading guest molecules. After processing or modification, the starch-containing channel structures can be used for food and drug encapsulation and delivery. This article reviews the formation and determination of starch internal channels, and the influence of different factors (such as starch species and processing conditions) on the channel structure. It also discusses relevant starch preparation methods (physical, chemical, enzymatic, and synergistic), and the encapsulation effect of starch containing internal channels on different substances. In addition, the role of internal channels in regulating the starch digestion rate and other aspects is also discussed here. This review highlights the significant multifunctional applications of starch with a channel structure
Effects of temperature and solvent condition on phase separation induced molecular fractionation of gum arabic/hyaluronan aqueous mixtures
Effects of temperature and solvent condition on phase separation-induced molecular fractionation of gum arabic/hyaluronan (GA/HA) mixed solutions were investigated. Two gum arabic samples (EM10 and STD) with different molecular weights and polydispersity indices were used. Phase diagrams, including cloud and binodal curves, were established by visual observation and GPC-RI methods. The molecular parameters of control and fractionated GA, from upper and bottom phases, were measured by GPC-MALLS. Fractionation of GA increased the content of arabinogalactan-protein complex (AGP) from ca. 11% to 18% in STD/HA system and 28% to 55% in EM10/HA system. The phase separation-induced molecular fractionation was further studied as a function of temperature and solvent condition (varying ionic strength and ethanol content). Increasing salt concentration (from 0.5 to 5 mol/L) greatly reduced the extent of phase separation-induced fractionation. This effect may be ascribed to changes in the degree of ionization and shielding of the acid groups. Increasing temperature (from 4oC to 80oC) also exerted a significant influence on phase separation-induced fractionation. The best temperature for GA/HA mixture system was 40oC while higher temperature negatively affected the fractionation due to denaturation and possibly degradation in mixed solutions. Increasing the ethanol content up to 30% showed almost no effect on the phase separation induced fractionation
Hypofractionated radiotherapy with immunochemotherapy for extensive-stage small-cell lung cancer
IntroductionThe combination of a PD-L1 inhibitor plus carboplatin/cisplatin and etoposide (EC/EP) has become a new standard first-line treatment for extensive-stage small-cell lung cancer (ES-SCLC). Combining concurrent palliative hypofractionated radiotherapy of the thorax (HFRT) and immunochemotherapy may have a synergistic effect. In this study, we explored an optimal model of combination radiotherapy with immunochemotherapy as first-line treatment of ES-SCLC.Patients and methodsIn this multicenter single-arm phase 2 trial, patients with ES-SCLC received atezolizumab with EC/EP for two cycles (induction phase), then, those who did not progress received concurrent palliative HFRT and two cycles of atezolizumab with EC/EP (combination phase). Afterward they received atezolizumab every 3 weeks for a maximum of 2 years after study enrolment (maintenance phase). Prophylactic cranial irradiation (PCI) was recommended. The primary endpoints were safety and tolerance; the second endpoints were progression-free survival (PFS).ResultsForty patients were enrolled, and all had completed palliative HFRT and four cycles of immunochemotherapy. There were seven grade 3 adverse events (3 decreased neutrophil count, 1 anemia, 2 pneumonitis, 1 esoenteritis), two grade 4 adverse events (2 decreased white cell count) and no grade 5 toxicities. The pneumonitis rate was 12.5% (three grade 2 and two grade 3 events). At the median follow-up of 14.2 months (range, 6.8–28.7), the median PFS was 8.6 months (95%CI, 6.1–11.1).ConclusionThe addition of concurrent hypofractionated thoracic radiotherapy to first-line immunochemotherapy for ES-SCLC was well tolerated and showed promising clinical efficacy. Additional randomized trials are needed to validate benefits.Clinical trial registrationhttps://clinicaltrials.gov/ (NCT 04636762)
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