Magnetic nanoparticles (MNPs) have been extensively explored as magnetic resonance imaging (MRI) contrast agents. With the increasing complexity in the structure of modern MNPs, the classical ...Solomon–Bloembergen–Morgan and the outer‐sphere quantum mechanical theories established on simplistic models have encountered limitations for defining the emergent phenomena of relaxation enhancement in MRI. Recent progress in probing MRI relaxivity of MNPs based on structural features at the molecular and atomic scales is reviewed, namely, the structure–relaxivity relationships, including size, shape, crystal structure, surface modification, and assembled structure. A special emphasis is placed on bridging the gaps between classical simplistic models and modern MNPs with elegant structural complexity. In the pursuit of novel MRI contrast agents, it is hoped that this review will spur the critical thinking for design and engineering of novel MNPs for MRI applications across a broad spectrum of research fields.
Structure–relaxivity relationships between different structural features of magnetic nanoparticles (MNPs) and the resulting T1 and T2 relaxivities in magnetic resonance imaging (MRI) are reviewed. The factors of size, shape, crystal structure, surface functionality, and assembly structure of magnetic nanoparticles are summarized to decipher how physical properties of MNPs influence proton relaxation in MRI.
This review contributes towards a systematic understanding of the mechanism of shape-dependent effects on nanoparticles (NPs) for elaborating and predicting their properties and applications based on ...the past two decades of research. Recently, the significance of shape-dependent physical chemistry and biomedicine has drawn ever increasing attention. While there has been a great deal of effort to utilize NPs with different morphologies in these fields, so far research studies are largely localized in particular materials, synthetic methods, or biomedical applications, and have ignored the interactional and interdependent relationships of these areas. This review is a comprehensive description of the NP shapes from theory, synthesis, property to application. We figure out the roles that shape plays in the properties of different kinds of nanomaterials together with physicochemical and biomedical applications. Through systematic elaboration of these shape-dependent impacts, better utilization of nanomaterials with diverse morphologies would be realized and definite strategies would be expected for breakthroughs in these fields. In addition, we have proposed some critical challenges and open problems that need to be addressed in nanotechnology.
This review is a systematic description of shape-dependent effects on nanomaterials from theory, synthesis, property to application, meanwhile, elaborates and predicts the properties and applications of nanoparticles with diverse morphologies in physicochemical and biomedical fields.
This study proposes a probabilistic methodology for estimating the business interruption loss of industrial sectors as an extension of current methodology. The functional forms and parameters are ...selected and calibrated based on survey data obtained from businesses located in the inundated area at the time of the 2000 Tokai Heavy Rain in Japan. The Tokai Heavy Rain was a rare event that hit a densely populated and industrialized area. In the estimation of business interruption losses, functional fragility curves and accelerated failure time models are selected to estimate the extent of damage to production capacity and production recovery time. Significant explanatory variables, such as inundation depth, distinct vulnerability, and the resilience characteristics of each sector, as well as the accuracy of fit of the model, are analyzed in the study. The function obtained and the estimated parameters can be utilized as benchmarks in estimating the probabilistic distribution of business interruption losses, especially in the case of urban flood disasters.
With growing regional economic integration, transportation systems have become critical to regional development and economic vitality but vulnerable to disasters. However, the regional economic ...ripple effect of a disaster is difficult to quantify accurately, especially considering the cumulated influence of traffic disruptions. This study explored integrating transportation system analysis with economic modeling to capture the regional economic ripple effect. A state-of-the-art spatial computable general equilibrium model is leveraged to simulate the operation of the economic system, and the marginal rate of transport cost is introduced to reflect traffic network damage post-disaster. The model is applied to the 50-year return period flood in 2020 in Hubei Province, China. The results show the following. First, when traffic disruption costs are considered, the total output loss of non-affected areas is 1.81 times than before, and non-negligible losses reach relatively remote zones of the country, such as the Northwest Comprehensive Economic Zone (36% of total ripple effects). Second, traffic disruptions have a significant hindering effect on regional trade activities, especially in the regional intermediate input—about three times more than before. The industries most sensitive to traffic disruptions were transportation, storage, and postal service (5 times), and processing and assembly manufacturing (4.4 times). Third, the longer the distance, the stronger traffic disruptions’ impact on interregional intermediate inputs. Thus, increasing investment in transportation infrastructure significantly contributes to mitigating disaster ripple effects and accelerating the process of industrial recovery in affected areas.
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Inflammatory bowel disease (IBD), comprising Crohn’s disease (CD) and ulcerative colitis (UC), is a set of clinically chronic, relapsing gastrointestinal inflammatory disease and ...lacks of an absolute cure. Although the precise etiology is unknown, developments in high-throughput microbial genomic sequencing significantly illuminate the changes in the intestinal microbial structure and functions in patients with IBD. The application of microbial metabolomics suggests that the microbiota can influence IBD pathogenesis by producing metabolites, which are implicated as crucial mediators of host-microbial crosstalk. This review aims to elaborate the current knowledge of perturbations of the microbiome–metabolome interface in IBD with description of altered composition and metabolite profiles of gut microbiota. We emphasized and elaborated recent findings of several potentially protective metabolite classes in IBD, including fatty acids, amino acids and derivatives and bile acids. This article will facilitate a deeper understanding of the new therapeutic approach for IBD by applying metabolome-based adjunctive treatment.
Global warming has led to frequent flood disasters, which pose great uncertainty and risk to the normal operation of enterprises. To identify the key risk factors of business interruption for Chinese ...enterprises because of flood disasters, this study proposes an analysis framework based on social network analysis. We consider 248 cases of enterprises affected by floods reported since 2001 in China as the dataset, and quantitatively analyze the key risk factors and important factor combinations of enterprise business interruption because of floods through multiple indicators. These include the core-periphery, node centrality, and note pairings in social network analysis. The analysis results show that “factory building damage,” “production equipment damage,” and “power supply interruption” are the key risk factors of business interruption during flood disasters. The three most likely combinations of risk factors to occur simultaneously are “production equipment damage and factory building damage,” “production equipment damage and raw material damage,” and “production equipment damage and power supply interruption.”
The appearance of multidrug-resistant bacteria and the formation of bacterial biofilms have necessitated the development of alternative antimicrobial therapeutics. Antibiotics conjugated with or ...embedded in nano-drug carriers show a great potential and advantage over free drugs, but the mass proportion of carriers generally exceeds 90% of the nano-drug, resulting in low drug loading and limited therapeutic output. Herein, we fabricated a nanocarrier using antibiotics as the building blocks, minimizing the use of carrier materials, significantly increasing the drug loading content and treatment effect. Firstly, we conjugated betaine carboxylate with ciprofloxacin (CIP) through an ester bond to form the amphiphilic conjugate (CIP-CB), which self-assembled into micelles (CIP-CBMs) in aqueous solutions, with a CIP loading content as high as 65.4% and pH-induced surface charge reversal properties. Secondly, a model photosensitizer (5, 10, 15, 20-tetraphenylporphyrin (TPP)) was encapsulated in CIP-CBMs, generating infection-targeted photodynamic/antibiotic combined nanomedicines (denoted as TPP@CIP-CBMs). Upon accumulation at infection sites or in deep bacterial biofilms, the ester bond between the betaine carboxylate and CIP is cleaved to release free TPP and CIP, leading to a synergetic antibacterial and antibiofilm activity in vitro and in vivo.
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In the early days of the Covid-19 pandemic, China implemented the most stringent and serious emergency response. To understand the effect of such an emergency response strategy on the economic ...system, this study proposed a simultaneous overall estimation method using intracity travel intensity data. The overall effect is represented by the difference between intracity travel intensity with and without the emergency response. Using historical data and time series analysis, we compared intracity travel intensity post China’s implementation of the emergency response with predicted intracity travel intensity without such a response. The loss rates, defined by the proportion of intracity travel intensity loss, were calculated for 360 cities within 33 provincial-level regions in China based on data availability. We found that 30 days after the emergency response, 21% of the cities saw over 80% recovery and 10% of the cities showed more than 90% recovery; 45 days after the emergency response, more than 83% of the 360 cities witnessed 80% recovery. The correlation between gross domestic production loss rate and travel intensity loss rate was studied quantitatively to demonstrate the representativeness of the intracity travel intensity loss rate. This indicator was also used to analyze the spatial and temporal patterns of the effects on the economy. The results of this study can help us understand the economic effects caused by the early Covid-19 emergency response and the method can be a reference for fast and real-time economic loss estimation to support emergency response decision making under pandemic conditions.
With the wide application of intense lasers, the protection of human eyes and detectors from laser damage is becoming more and more strict. In this paper, we study the nonlinear optical limiting (OL) ...properties of porous carbon with a super large specific surface area (2.9 × 10
m
/g) using the nanosecond Z-scan technique. Compared to the traditional OL material C
, the porous carbon material shows an excellent broadband limiting effect, and the limiting thresholds correspond to 0.11 J/cm
for 532 nm and 0.25 J/cm
for 1064 nm pulses, respectively. The nonlinear scattering experiments showed that the OL behavior was mainly attributed to the nonlinear scattering effect, which is caused by the rapid growth and expansion of bubbles in the dispersion induced by laser irradiation, and the scattered light distribution is consistent with the results of Mie's scattering. These results suggest that porous carbon materials are expected to be applied to the field of laser protection in the future to further protect the human eye and precision optical instruments.
The application of risk management strategies is a common approach in emergency response scenarios. However, scant knowledge exists regarding its utilization in the specific context of an outbreak, ...both theoretically and practically. This study delves into the realm of risk management during the COVID-19 pandemic, focusing on four key measurements: risk avoidance (RA), risk reduction (RD), risk transfer (RT), and risk retention (RR). Using 800 valid responses collected from 31 provinces across China between August 1 and September 30, 2020, this study investigates spatial disparities in individuals’ intentions towards risk management. To achieve this, an extended version of the Theory of Planned Behavior (E-TPB) is applied. The Structural Equation Model’s path analyses revealed several findings: (1) discernible spatial disparities in RR, RA, and RD intentions between large and small cities; (2) RD and RR intentions were significantly associated with attitude, subjective norm, perceived behavioral control, and risk perception; (3) RA and RT intentions were significantly associated with attitude and risk perception; (4) risk perception exihibiting both direct and indirect effects on RA and RR intentions. This study contributs to the urban studies literature by extending the theoretical framework of risk management in the context of COVID-19. It enhances the measurement tools employed in the TPB model and scrutinizes spatial disparities in the adoption of preventative measures against COVID-19. The findings underscore the importance for local policymakers to consider geographical differences when formulating effective strategies for COVID-19 prevention.
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