263 research outputs found
MODEL OF CROATIAN SEA PASSENGER PORTS MANAGEMENT RATIONALIZATION
Predmet istraživanja u ovome znanstvenom radu je razvitak pomorskoputničkih luka u Republici Hrvatskoj do 2012. godine. Za definiranje svojstava i determinanti pomorskoputničkih luka koristilo se modelom na bazi matrice rasta. Analiza i vrednovanje pojedinih elemenata modela i dobivene izravne stope rasta imale su za cilj znanstveno formulirati rezultate istraživanja, prema najvažnijim teorijskim zakonitostima razvitka pomorskoputničkih luka u Republici Hrvatskoj. Autori su se u znanstvenom istraživanju i prezentiranju rezultata istraživanja ovog rada služili kombinaciju znanstvenih metoda kao što su: metoda analize i sinteze, metoda konkretizacije, komparativna metoda i metoda modeliranja (matrica rasta). Glavna znanstvena hipoteza dokazana je izravnim stopama rasta odabranih elemenata modela a ona glasi: Znanstveno utemeljenim spoznajama o funkcioniranju i poslovanju sustava pomorskoputničkih luka moguće je predložiti model, mjere i aktivnosti za racionalno upravljanje tim lukama kako bi se osigurao rast i razvoj sustava pomorskoputničkih luka.This paper analyses the sustainable development of sea passenger ports in the Republic of Croatia until 2012. A model of growth was used in order to define the main characteristics and determinants of sea passenger ports. The purpose of the paper was to present a scientifically-based formulation of sustainable development analysis of sea passenger ports in Croatia, based on the evaluation and analysis of relevant elements and resulting direct rates. The authors in their scientific research and presentation used a various combination of scientific methods like: analysis and syntheses method, concretization method, comparative method and modeling method (growth matrix). The main scientific hypothesis is: By using scientifically based acknowledgments about functioning and management of sea passenger port system it is possible to suggest a model, measurements and activities for the rational management of sea passenger ports in Croatia in order to secure their growth and development. This scientific hypothesis was confirmed by the direct rates of growth of the model elements
Cyclophilin a represses reactive oxygen species generation and death of hypoxic non-small-cell lung cancer cells by degrading thioredoxin-interacting protein
Cyclophilin A (cypA) is overexpressed in many types of carcinomas, including non-small-cell lung cancer (NSCLC). However, the effect of anoxia, a critical feature of the carcinoma cell microenvironment, on cypA expression in NSCLC is unknown. Here, formaldehyde-fixed and paraffin-embedded samples were collected from 60 subjects with NSCLC. The protein expression levels of cypA and hypoxia-inducible factor-1α (HIF-1α) were evaluated using immunohistochemistry. Kaplan–Meier analysis showed that subjects with high cypA expression had remarkably shorter progression-free survival than those with low cypA expression. Furthermore, cypA expression levels were significantly related to HIF-1α expression levels (Spearman’s correlation = 0.34, P < 0.0001). To further assess the effect of cypA, an anoxic carcinoma cell model was established. CypA expression was remarkably upregulated in H1299 and A549 cell lines under hypoxic conditions. Overexpression of cypA restored hypoxia-impaired cell growth and prevented reactive oxygen species (ROS) production and cell death in hypoxic A549 and H1299 cells. However, these phenotypes were not altered by the inactive R55A mutant of cypA. Mechanistic studies demonstrated that cypA can bind to and degrade the tumor suppressor protein TXNIP in H1299 and A549 cells. Restored TXNIP expression in cypA-overexpressed and hypoxic NSCLC cells led to increased ROS levels and apoptotic cell numbers and decreased cell growth compared with cypA-overexpressed and hypoxic NSCLC cells. These findings indicate that anoxia results in an increase in cypA expression in NSCLC. Additionally, cypA served as an oncogene during hypoxia by interacting with TXNIP.</p
Opto-thermal dynamics in whispering-gallery microresonators
Optical whispering-gallery-mode microresonators with ultrahigh quality factors and small mode volumes have played an important role in modern physics. They have been demonstrated as a diverse platform for a wide range of photonics applications, such as nonlinear optics, optomechanics, quantum optics, and information processing. Thermal behaviors induced by power buildup in resonators or environmental perturbations are ubiquitous in high-quality-factor whispering-gallery-mode resonators and have played an important role in their operation for various applications. Here in this review, we discuss the mechanisms of laser field induced thermal nonlinear effects, including thermal bistability and thermal oscillation. With the help of the thermal bistability effect, optothermal spectroscopy and optical non-reciprocity have been demonstrated. On the other hand, by tuning the temperature of the environment, the resonant mode frequency will shift, which could also be used for thermal sensing/tuning applications. Thermal locking technique and thermal imaging mechanisms are discussed briefly. Last, we review some techniques to realize thermal stability in a high-quality-factor resonator system
Non-Hermitian physics and engineering in silicon photonics
Silicon photonics has been studied as an integratable optical platform where numerous applicable devices and systems are created based on modern physics and state-of-the-art nanotechnologies. The implementation of quantum mechanics has been the driving force of the most intriguing design of photonic structures, since the optical systems are found of great capability and potential in realizing the analogues of quantum concepts and phenomena. Non-Hermitian physics, which breaks the conventional scope of quantum mechanics based on Hermitian Hamiltonian, has been widely explored in the platform of silicon photonics, with promising design of optical refractive index, modal coupling and gain-loss distribution. As we will discuss in this chapter, the unconventional properties of exceptional points and parity-time symmetry realized in silicon photonics have created new opportunities for ultrasensitive sensors, laser engineering, control of light propagation, topological mode conversion, etc. The marriage between the quantum non-Hermiticity and classical silicon platforms not only spurs numerous studies on the fundamental physics, but also enriches the potential functionalities of the integrated photonic systems
Significantly Enhanced Visible-Light-Induced Photocatalytic Performance of Hybrid Zn–Cr Layered Double Hydroxide/Graphene Nanocomposite and the Mechanism Study
In
the present work, hybrid nanocomposites of Zn-Cr layered double
hydroxide (ZnCr-LDH) and graphene were assembled successfully via
a simple one-step coprecipitation method. The assembly process included
the nucleation and growth of ZnCr-LDH crystals and the simultaneous
reduction of GO in the absence of additional reducing agents. The
experimental results revealed that ZnCr-LDH nanoplatelets with the
diameter size of ∼6 nm were well dispersed on the graphene
surface, and as-assembled hybrid ZnCr-LDH/graphene nanocomposites
exhibited significantly improved visible-light-driven photocatalytic
activity in the degradation of Rhodamine B, in comparison with pure
ZnCr-LDH, which was attributable to the unique heteronanostructure
of ZnCr-LDH/graphene, facilitating the efficient transportation and
separation of photogenerated charges and thus continuously generating
reactive oxygen species. The present work could open a new doorway
for fabricating visible-light-deriven graphene-based photocatalysts
for pollutant degradation via an advanced oxidation process
Media 1: Dynamical thermal behavior and thermal self-stability of microcavities
Originally published in Optics Express on 04 October 2004 (oe-12-20-4742
Media 2: Dynamical thermal behavior and thermal self-stability of microcavities
Originally published in Optics Express on 04 October 2004 (oe-12-20-4742
Whispering gallery mode microresonator for nonlinear optics
Whispering gallery mode (WGM) microresonators, benefitting from the ultrahigh quality (Q) factors and small mode volumes, could considerably enhance the light-matter interaction, making it an ideal platform for studying a broad range of nonlinear optical effects. In this review, the progress of optical nonlinear effects in WGM microresonators is comprehensively summarized. First, several basic nonlinear effects in WGM microresonator are reviewed, including not only Pockels effect and Kerr effect, but also harmonic generations, four-wave mixing and stimulated optical scattering effects. Apart from that, nonlinearity induced by thermal effect and in PT-symmetric systems are also discussed. Furthermore, multistep nonlinear optical effects by cascading several nonlinear effects are reviewed, including frequency comb generations. Several selected applications of optical nonlinearity in WGM resonators are finally introduced, such as narrow-linewidth microlasers, nonlinearity induced non-reciprocity and frequency combs
Scatterer assisted whispering gallery mode microprobe
Fiber based whispering-gallery-mode (WGM) microprobe, combining both the high optical field enhancement of the WGMs and the practicability of the fiber probe, is highly demanded in sensing and imaging. Here in this paper, we experimentally report the efficient far-field coupling of WGMs by scattering the focused laser beam through a nanotip. With the help of Purcell effect as well as the two-step focusing technique, a WGM excitation efficiency as high as 16.8% has been achieved. Both the input and output of the probe light propagate along the same fiber, which makes the whole coupling system a fiber based WGM microprobe for sensing/imaging applications
Optomechanically Induced Transparency at Exceptional Points
We study optomechanically induced transparency in a microresonator coupled with nanoparticles. By tuning the relative angle of the nanoparticles, exceptional points (EPs) emerge periodically in this system and thus strongly modify both the transmission rate and the group delay of the signal. As a result, controllable slow-to-fast light switching can be achieved by manipulating external nanoparticles. This provides a new way to engineer EP-assisted optomechanical devices for applications in optical communications and signal processing
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