Differently sized NaGdF4 nanocrystals with narrow particle size distributions were synthesized by a high temperature approach. Upon ligand exchange, the as-prepared hydrophobic NaGdF4 nanocrystals ...were transferred into water by using asymmetric PEGs simultaneously bearing phosphate and maleimide groups. Further investigations demonstrated that the water-soluble NaGdF4 nanocrystals, coated by PEG bearing two phosphate groups on the same side, exhibit not only excellent colloidal stability in water and PBS buffer, but also higher T1 relaxivity than Gd-DTPA (Magnevist). Through “click” reaction between the maleimide residue on particle surface and thiol group from the partly reduced anti-EGFR monoclonal antibody (mAb), NaGdF4–PEG-mAb nanoprobes were constructed, and their biocompatibility and binding specificity were evaluated through in vitro experiments. A series of in vivo experiments were then carried out for detecting intraperitoneal tumor xenografts in nude mice by using magnetic resonance (MR) imaging technique. The results revealed that the NaGdF4–PEG-mAb probes possessed satisfying tumor-specific targeting ability and strong MR contrast enhancement effects.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Quality sleep is essential for human health. Recent developments in sleep monitoring techniques show great promise of detecting sleep disorders and improving sleep quality. Two important indicators ...for sleep disorders are breathing and posture, but existing methods deal with them separately, and hardly any effort has been devoted to head posture. In this paper, we present the design and implementation of a novel sleep monitoring system that simultaneously analyzes respiration, head posture, and body posture. The system consists solely of cost-effective vision-based devices, operating in a quiet and noncontact way with a little disturbance to natural sleep. Specifically, we use an infrared camera to record the sleep process. From the infrared video, the region of breathing movement is automatically determined and the intensity estimated, yielding a waveform indicating respiratory rhythms. Five additional infrared cameras are employed to capture the subject's face from different orientations, and we exploit template matching to perform head tracking. A Kinect motion sensor is also utilized to obtain skeleton description of body posture that is robust to self-occlusion, and after noise being filtered, we apply machine learning techniques for body posture classification. Experimental results show that elementary breathing and posture analysis are feasible based on the information acquired by the proposed system, and high accuracy can be achieved: 96% in recognizing abnormal breathing and body movements, 87.6% in head tracking, and over 90% in classifying most body postures.
Event cameras as bioinspired vision sensors have shown great advantages in high dynamic range and high temporal resolution in vision tasks. Asynchronous spikes from event cameras can be depicted ...using the marked spatiotemporal point processes (MSTPPs). However, how to measure the distance between asynchronous spikes in the MSTPPs still remains an open issue. To address this problem, we propose a general asynchronous spatiotemporal spike metric considering both spatiotemporal structural properties and polarity attributes for event cameras. Technically, the conditional probability density function is first introduced to describe the spatiotemporal distribution and polarity prior in the MSTPPs. Besides, a spatiotemporal Gaussian kernel is defined to capture the spatiotemporal structure, which transforms discrete spikes into the continuous function in a reproducing kernel Hilbert space (RKHS). Finally, the distance between asynchronous spikes can be quantified by the inner product in the RKHS. The experimental results demonstrate that the proposed approach outperforms the state-of-the-art methods and achieves significant improvement in computational efficiency. Especially, it is able to better depict the changes involving spatiotemporal structural properties and polarity attributes.
Markov random fields (MRF) underpin the solution to many problems in computational neuroscience. However, how the inference for MRF could be implemented with neural network is still an important open ...question. In this paper, we build the relationship between inference equation of MRF and the dynamic equation of the Hopfield network with probability coding. We prove that the membrane potential in the Hopfield network varying with respect to time can implement marginal probabilities inference on binary MRF. Theoretical analysis and experimental results show that our neural network can get comparable results as that of loopy belief propagation (LBP).
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A detailed analysis of the dehydrogenation mechanism of LiBH4/xLiAlH4 (x = 0.5, 1, 2) composites was performed by thermogravimetry (TG), differential scanning calorimetry (DSC), mass spectral ...analysis (MS), powder X-ray diffraction (XRD) and scanning electronic microscopy (SEM), along with kinetic investigations using a Sievert-type apparatus. The results show that the dehydrogenation pathway of LiBH4/xLiAlH4 had a four-step character. The experimental dehydrogenation amount did not reach the theoretical expectations, because the products such as AlB2 and LiAl formed a passivation layer on the surface of Al and the dehydrogenation reactions associated with Al could not be sufficiently carried out. Kinetic investigations discovered a nonlinear relationship between the activation energy (Ea) of dehydrogenation reactions associated with Al and the ratio x, indicating that the Ea was determined both by the concentration of Al produced by the decomposition of LiAlH4 and the amount of free surface of it. Therefore, the amount of effective contact surface of Al is the rate-determining factor for the overall dehydrogenation of the LiBH4/xLiAlH4 composites.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Prognostic studies of insulin-like growth factor-1 receptor(IGF-1R) inhibitors in cancer therapy had promising results in infratests, which exhibited that IGF-1R signalling was crucial in cancer ...cells growth. However, the conclusion of later clinical trials revealed a dim future for IGF-1R inhibitors to treat cancer. We conducted this analysis to figure out how IGF-1R inhibitors acted in clinical cancer therapy.
We searched up-to-date studies about the single agent of IGF-1R inhibitors or combination with other therapies in solid tumor. Five IGF-1R anti-agents were involved. The primary endpoint was progression-free survival (PFS). The secondary endpoint was overall survival (OS).
17studies were enrolled. The results was not significant in overall survival (I2=37.1%, P=0.080, HR=1.08, 95% CI=0.97-1.21) and in progression-free survival (I2=0.0%, P=0.637, HR=1.05, 95% CI=0.98-1.12). OS for dalotuzumab, breast cancer, colorectal cancer, and PFS for prostate cancer even indicated harmful effects.
So far, anti-IGF-1R mono-antibodies did not make significant differences in solid tumor prognosis. On the contrary, pessimistic effects were shown in the dalotuzumab, breast cancer, colorectal cancer and prostate cancer subgroups. Further studies of IGF-1R anti-agents were needed, but unwarranted in unselected patients by predictive biomarkers.
Plant phenology is the bridge between climate change and ecosystem functions. Time coordination of interspecific and intraspecific phenology changes overlap or separate can be regarded as an ...important characteristic of species coexistence. To confirm the hypothesis that plant phenological niche promotes species coexistence, three key alpine plants, Kobresia humilis (sedge), Stipa purpurea (grass), and Astragalus laxmannii (forb) were investigated in this study in the Qinghai-Tibet Plateau. Phenological niches represented as the duration of green up-flowering, flowering-fruiting, and fruiting-withering by 2-day intervals for phenological dynamics of three key alpine plants from 1997 to 2016. We found the role of precipitation on regulating the phenological niches of alpine plants was highlighted in the context of climate warming. The response of the intraspecific phenological niche of the three species to temperature and precipitation is different, and the phenological niche of Kobresia humilis and Stipa purpurea was separate, especially in the green up-flowering. But the overlapping degree of interspecific phenological niche of the three species has continued to increase in the past 20 years, reducing possibility of species coexistence. Our findings have profound implications for understanding the adaptation strategies of key alpine plants to climate change in the dimension of phenological niche.
Display omitted
•Precipitation regulated the phenological niches of alpine plants.•Sedge shifted from vegetative growth to longer reproductive growth.•Grass prolonged the vegetative growth.•Alpine plants increased the overlap of phenological niches.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Ecosystem invasibility to a nonnative invasive species can be quantified through metrics measuring ecosystem structure.•In a landscape managed by frequent, low-intensity prescribed fires, pine ...flatwoods are more susceptible to Chinese tallow invasion than pine savannas.•High invasibility of pine flatwoods is mainly attributed to its high overstory basal area but low understory shrub cover.•Short fire intervals increase invasion probability, but the impact of fire on tallow changes with invasion stages.•Short fire intervals promote the recruitment of tallow seedlings and saplings; while long fire intervals favor the development of large trees.
The Chinese tallow tree (Triadica sebifera, hereafter, tallow) is a nonnative invasive species that has invaded diverse ecosystems including forests, prairies and wetlands in the Gulf Coastal Plain of the southeastern United States. We proposed a landscape (ecosystem)-level modeling framework of tallow invasion and applied it to a fire-managed landscape to evaluate the effect of prescribed fire on tallow invasion and ecosystem invasibility. A spatially random sample consisting of 55 0.04-ha circular plots was installed in a landscape of appropriately 2,900 ha in the Mississippi Sandhill Crane National Wildlife Refuge in 2015. These plots, plus ten additional tallow-invaded plots from another study were measured in May-June of 2015 and remeasured in November of 2018. Across the entire landscape, pine flatwoods (invasion probability = 0.52) were generally more susceptible to tallow invasion than pine savannas (invasion probability = 0.16) (p = 0.002), and the former had a greater number of tallow seedlings and saplings (p < 0.001), but fewer large tallow trees (p = 0.07) than the latter. The effect of fire on tallow invasion is two-fold and changes with fire return intervals and ecosystem conditions. Fire may promote seed germination and seedling recruitment, but recurrent fires top-kill or even completely kill young seedlings and saplings. Large proportions of invaded plots and abundant tallow seedlings and saplings that accumulate in pine flatwoods are essentially attributed to their high overstory tree basal area but relatively low shrub/grass coverage. On sites near roadways or with tallow seed trees, short fire intervals tend to increase invasion probability and the abundance of tallow seedlings and saplings, whereas long fire intervals increase the abundance of large tallow trees. Under current fire treatments, pine flatwoods are more susceptible to seedling colonization and sapling establishment, while pine savannas favor the growth and development of large tallow trees.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
