383 research outputs found
Ou Mei ming zhu jie ben. v.1
No full text王昌謨 ... [et al.] 編譯 ; 任鴻雋 ... [et al.] 校.Wang Changmo ... [et al.] bian yi ; Ren Hongjun ... [et al.] jiao
Polyetherimide-grafted Fe<sub style="box-sizing: border-box; position: relative; font-size: 0.7em; line-height: 0; bottom: -0.25em; margin: 0px; padding: 0px; border: 0px; outline: 0px; background: 0px 0px;">3</sub>O<sub style="box-sizing: border-box; position: relative; font-size: 0.7em; line-height: 0; bottom: -0.25em; margin: 0px; padding: 0px; border: 0px; outline: 0px; background: 0px 0px;">4</sub>@SiO<sub style="box-sizing: border-box; position: relative; font-size: 0.7em; line-height: 0; bottom: -0.25em; margin: 0px; padding: 0px; border: 0px; outline: 0px; background: 0px 0px;">2</sub> nanoparticles as theranostic agents for simultaneous VEGF siRNA delivery and magnetic resonance cell imaging
No full textEngineering a safe and high-efficiency delivery system for efficient RNA interference is critical for successful gene therapy. In this study, we designed a novel nanocarrier system of polyethyleneimine (PEI)-modified Fe3O4@SiO2, which allows high efficient loading of VEGF small hairpin (sh)RNA to form Fe3O4@SiO2/PEI/VEGF shRNA nanocomposites for VEGF gene silencing as well as magnetic resonance (MR) imaging. The size, morphology, particle stability, magnetic properties, and gene-binding capacity and protection were determined. Low cytotoxicity and hemolyticity against human red blood cells showed the excellent biocompatibility of the multifunctional nanocomposites, and also no significant coagulation was observed. The nanocomposites maintain their superparamagnetic property at room temperature and no appreciable change in magnetism, even after PEI modification. The qualitative and quantitative analysis of cellular internalization into MCF-7 human breast cancer cells by Prussian blue staining and inductively coupled plasma atomic emission spectroscopy analysis, respectively, demonstrated that the Fe3O4@SiO2/PEI/VEGF shRNA nanocomposites could be easily internalized by MCF-7 cells, and they exhibited significant inhibition of VEGF gene expression. Furthermore, the MR cellular images showed that the superparamagnetic iron oxide core of our Fe3O4@SiO2/PEI/VEGF shRNA nanocomposites could also act as a T2-weighted contrast agent for cancer MR imaging. Our data highlight multifunctional Fe3O4@SiO2/PEI/VEGF shRNA nanocomposites as a potential platform for simultaneous gene delivery and MR cell imaging, which are promising as theranostic agents for cancer treatment and diagnosis in the future.</p
Rotated Half-Mode Substrate Integrated Waveguide and other Planar Integrated Structures
No full textHigh data rate communication channels are becoming more and more integrated into our increasingly technological society. Substrate Integrated Waveguides (SIW) are one planar solution available to the microwave engineer, offering a low-loss and low dispersion means of propagating these high speed, high bandwidth signals.
In this thesis, a brief synopsis of SIW structures and components is presented covering the basic waveguide propagating modes and cut-off frequencies. The main analysis techniques associated with SIWs including full wave electromagnetic modelling methods are overviewed, and the associated loss mechanisms of conduction, dielectric and radiation defined, leading to the design rules and guidelines on how best to mitigate them.
SIW antennas as both leaky-wave and radiating slots are discussed and an example of a single and dual resonating slot antenna design is presented, along with a detailed review of a novel switch beam antenna developed for use within the current WiFi bands.
The Slot SIW (or SSIW), which has a small longitudinal gap in one of the main conducting surfaces, allows easy integration of lumped elements or active devices, enabling the waveguide to be loaded with impedances or to be shorted. When the slot is shorted, the waveguide reverts back to the full SIW mode, and when partially loaded an intermediate state results. This is discussed, and the SSIW analysed with the transverse resonance technique, leading to the development of a travelling wave attenuator with the SSIW being periodically loaded with pin diodes. The application of the pin diodes required the use of a capacitive overlay, a development of flexi circuit design to allow capacitive coupling of impedances to connect to the waveguide. The overlay concept is extended further, to form novel passive bandpass filters, with the introduction of virtual vias.
A limitation of the SSIW is that the majority of the field resides within the dielectric; this allows only a limited interaction with the field at the slot. The rotated Half Mode SIW (rHMSIW), a new variant of the SIW family, places the maximum of the electric field directly on the top dielectric surface, allowing for direct interaction. The waveguide width a is now defined by the dielectric thickness, allowing for the waveguide height b to be adjustable, in normal SIWs this is the other way round; the dielectric thickness fixing the waveguide height and the waveguide width being adjustable. The rHMSIW is characterised with regard to the height and width ratios b/a and the dielectric exposed width (which is adjustable). These parameters effect the modal cut-off frequency, this is investigated and a new equation describing the fundamental mode cut-off frequency is empirically derived. Finally a test coupon which spans the Ku band is designed and measured, which required the development of a novel waveguide transition
Percentage of Qing officials gaining degrees through civil examination (all levels), Yin privilege, and purchase.
No full text‘Yin Privilege’ refers to the hereditary privilege enjoyed by the sons of higher officials who could inherit the title without standing for examinations. Sources [82,84,86].</p
Opportunistic scheduling algorithms in downlink centralized wireless networks.
No full textThesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2005.As wireless spectrum efficiency is becoming increasingly important with the growing demands
for wideband wireless service scheduling algorithm plays an important role in the
design of advanced wireless networks. Opportunistic scheduling algorithms for wireless
communication networks under different QoS constraints have gained popularity in recent
years since they have potentials of achieving higher system performance. In this dissertation
firstly we formulate the framework of opportunistic scheduling algorithms. Then
we propose three new opportunistic scheduling schemes under different QoS criteria and
situations (single channel or multiple channel).
1. Temporal fairness opportunistic scheduling algorithm in the short term.
We replicate the temporal fairness opportunistic scheduling algorithm in the long
term. From simulation results we find that this algorithm improves the system
performance and complies with the temporal fairness constraint in the long term.
However, the disadvantage of this algorithm is that it is unfair from the beginning
of simulation to 10000 time slot on system resource (time slots) allocation - we say
it is unfair in the short term. With such a scheme, it is possible that some users
with bad channel conditions would starve for a long time (more than a few seconds) ,
which is undesirable to certain users (say, real-time users). So we propose the new
scheme called temporal fairness opportunistic scheduling algorithm in the short term
to satisfy users ' requirements of system resource in both short term and long term.
Our simulation results show that the new scheme performs well with respect to both
temporal fairness constraint and system performance improvement.
2. Delay-concerned opportunistic scheduling algorithm.
While most work has been done on opportunistic scheduling algorithm under fairness
constraints on user level, we consider users' packet delay in opportunistic scheduling.
Firstly we examine the packet delay performance under the long term temporal
fairness opportunistic scheduling (TFOL) algorithm. We also simulate the earliest
deadline-first (EDF) scheduling algorithm in the wireless environment. We find that
the disadvantage of opportunistic scheduling algorithm is that it is unfair in packet
delay distribution because it results in a bias for users with good channel conditions
in packet delay to improve system performance. Under EDF algorithm, packet delay
of users with different channel conditions is almost the same but the problem is that
it is worse than the opportunistic scheduling algorithm. So we propose another new
scheme which considers both users' channel conditions and packet delay. Simulation
results show that the new scheme works well with respect to both system performance
improvement and the balance of packet delay distribution.
3. Utilitarian fairness scheduling algorithm in multiple wireless channel networks.
Existing studies have so far focused on the design of scheduling algorithm in the
single wireless communication network under the fairness constraint. A common
assumption of existing designs is that only a single user can access the channel
at a given time slot. However, spread spectrum techniques are increasingly being
deployed to allow multiple data users to transmit simultaneously on a relatively
small number of separate high-rate channels. Not much work has been done on
the scheduling algorithm in the multiple wireless channel networks. Furthermore
in wire-line network, when a certain amount of resource is assigned to a user, it
guarantees that the user gets some amount of performance, but in wireless network
this point is different because channel conditions are different among users. Hence,
in wireless channel the user's performance does not directly depend on its allocation
of system resource. Finally the opportunistic scheduling mechanism for wireless
communication networks is gaining popularity because it utilizes the "multi-user
diversity" to maximize the system performance. So, considering these three points
in the fourth section, we propose utilitarian fairness scheduling algorithm in multiple
wireless channel networks. Utilitarian fairness is to guarantee that every user can get
its performance requirement which is pre-defined. The proposed criterion fits in with
wireless networks. We also use the opportunistic scheduling mechanism to maximize
system performance under the utilitarian fairness constraint. Simulation results show
that the new scheme works well in both utilitarian fairness and utilitarian efficiency
of system resource in the multiple wireless channel situation
Approach for determination of ATP:ADP molar ratio in mixed solution by surface-enhanced Raman scattering
No full textGrowth and Characterisation of Boron Rich Nanomaterials
No full textIn this study nanomaterials are grown in a solid state reaction at 1300C of boron, barium oxide and iron(II/III)oxide powders in an argon atmosphere. The nanomaterials are shown to be grown via vapour based method by growing the nanomaterials on a separate silicon wafer that has been sputtered with iron and placed downstream of the powders in the flow of argon. An area of the silicon wafer is kept free of iron by using a mask when sputtering the wafer. When nanomaterials are grown, the masked area remains free of nanomaterials. This shows that the presence of iron is vital for the nucleation of the nanomaterials and also indicates the possibility of growing these nanomaterials on targeted sites.
The nanomaterials produced are examined and it is found that we have a presence of amorphous, crystalline and multiple twinned nanowires. The evidence collected suggests that 70% of the nanowires are twinned. The single crystal nanowires can be identified as boron carbide by comparing to diffraction pattern simulations of a boron carbide unit cell. The twinned diffraction pattern is shown to be due to different segments of the nanowire being in different diffraction condition by using Dark Field imaging. The Twinned wires are also shown to have at least four segments in a cyclic [001] twinning orientation in simultaneous diffraction condition by comparing to a twinned structure constructed from simulations. Elemental analysis using Electron Energy Loss Spectroscopy and Energy Dispersive X-ray shows that the composition of the nanomaterials is mainly boron and carbon.
The role of the iron layer on the wafer is investigated to see how varying the thickness will affect the nanomaterials grown. It is successfully shown that an increase in the thickness of the iron layer results in a greater density of nanomaterials. However there is no great variation in the average diameter of the nanomaterials produced.
The absence of a visible signal for iron in the Elemental analysis of nanostructure covered silicon wafer shows that the amount of iron in the sample has decreased during the reaction. However iron is found in small amounts in droplet structures at the tips of nanomaterials this is different to work done on a similar system at 1100C. This suggests that the role of the iron in the growth of these nanomaterials at this temperature is not yet understood. However this work has confirmed that the iron is essential for the nucleation of the nanomaterials, but post nucleation growth that was previously assumed to be a conventional VLS growth may switch to an oxide assisted growth mode
A Nomogram Model Integrating Inflammation Markers for Predicting the Risk of Recurrent Sciatica After Selective Nerve Root Blocks
No full textMeng Cai,* Jing Yin,* Yi Jin, HongJun Liu Department of Pain Medicine, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, People’s Republic of China*These authors contributed equally to this workCorrespondence: HongJun Liu, Department of Pain Medicine, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, 305# Zhongshan East Road, Nanjing, Jiangsu, 210002, People’s Republic of China, Email [email protected]: Lumbar disc herniation (LDH) usually c auses sciatica. Although selective nerve root block (SNRB) is an effective, highly target-oriented interventional procedure for patients with LDH, accurately predicting the risk of sciatica recurrence in such patients after SNRB remains a major challenge.Objective: We aimed to construct a nomogram model by integrating clinical data, imaging features and inflammation markers that could predict recurrent sciatica following SNRB in LDH patients, which fill the inflammation data gaps during model construction.Methods: In total, 121 sciatica patients were enrolled and assigned to the recurrence group (n = 41) and non-recurrence group (n = 80). By performing the logistic regression analyses, we identified risk factors serving as independent predictors and constructed the nomogram prediction model. Then, the performance and clinical practicality of the nomogram model were validated by performing the receiver operating characteristic curve (ROC) analysis, calibration curve analysis, and decision curve analysis (DCA). The bootstrap method was applied for the internal validation of the nomogram model.Results: Preoperative sensory symptoms (odds ratio [OR] [95% confidence interval (CI)]: 2.933 [1.211– 7.353]), type of herniation (OR [95% CI]: 2.712 [1.261– 6.109]), and systemic inflammation response index (OR [95% CI]: 2.447 [1.065– 6.271]) were included in the nomogram for predicting unfavorable outcomes following sciatica. The nomogram AUC was 0.764, and the prognostic precision, validated using the bootstrap method, reached 0.756. The ROC and calibration curve analyses, and DCA also produced excellent results, exhibiting favorable predictive performance and clinical benefit.Conclusion: This study thus identified risk factors that predict unfavorable outcomes after sciatica and developed a risk prediction model based on clinical, radiologic, and inflammatory factors, thereby facilitating early predictions by clinicians and offering an individualized medical interventions for patients with recurrent sciatica in early stages.Keywords: lumbar disc herniation, sciatica, selective nerve block, nomogra
On Optimal Method of Cargo Flows Distribution in Large Logistics Park Based on Random Decisive Genetic Algorithm
No full textResearch on Optimization of Random Storage Capacity with Analysis of Scientific Materials in Logistics System
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