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Additional file 3. Supplemental figures.

In order to increase the utilization rate of drug carried by microneedles and reduce waste, a two-step casting method was proposed to fabricate tip-loaded dissolving microneedles in this paper. The tip-loaded dissolving microneedles, also named layered microneedles, was consisted of two layers. The tip layer of the microneedles carried model drug, while the backing layer was fabricated with pure dissolving material. Polyvinyl alcohol, polyvinylpyrrolidone and hyaluronic acid were used as the base materials to fabricate the dissolving layers of the microneedle patches. Rhodamine B was chosen as the model drug to show the layered structure of tip-loaded microneedles. The material formulation and fabricating conditions of the tip-loaded dissolving microneedles and their transdermal insulin delivery efficiency were systematically studied. Nanoindentation testing showed that the tips of all three kinds of dissolving microneedles can bear the maximum loading of 50 mN with no damages, indicated sufficient mechanical strength for smooth skin puncturing as the minimum pressure required was 10 mN only. Moreover, our fabricated tip-loaded dissolving microneedles can greatly reduce the drug waste cause by unused backing layer in normal microneedles and realize a 30% enhancement of drug delivery efficiency after puncture treatment.

Cartilage defect is common in clinical but notoriously difficult to treat for low regenerative and migratory capacity of chondrocytes. Biodegradable tissue engineering nano-scaffold with a lot of advantages has been the direction of material to repair cartilage defect in recent years. The objective of our study is to establish a biodegradable drug-loading synthetic polymer (PLA) and biopolymer (Gelatine) composite 3D nano-scaffold to support the treatment of cartilage defect. We designed a microfluidic chip-based drug-screening device to select the optimum concentration of resveratrol, which has strong protective capability for chondrocyte. Then biodegradable resveratrol-loading PLA/Gelatine 3D nano-scaffolds were fabricated and used to repair the cartilage defects. As a result, we successfully cultured primary chondrocytes and screened the appropriate concentrations of resveratrol by the microfluidic device. We also smoothly obtained superior biodegradable resveratrol-loading PLA/Gelatine 3D nano-scaffolds and compared the properties and therapeutic effects of cartilage defect in rats. In summary, our microfluidic device is a simple but efficient platform for drug screening and resveratrol-loading PLA/Gelatine 3D nano-scaffolds could greatly promote the cartilage formation. It would be possible for materials and medical researchers to explore individualized pharmacotherapy and drug-loading synthetic polymer and biopolymer composite tissue engineering scaffolds for the repair of cartilage defect in future.

The dry etching characteristic of new Ti0.5Sb2Te3(TST) phase change material was investigated by using the CF4 and Ar gas mixture. The research mainly focuses on how to optimize the experimental parameters such as gas flow rate within the chamber, CF4 /Ar flow ratio, the chamber background pressure and the incident RF power applied to the lower electrode. The results show that CF4 mainly plays a role of chemical etching and Ar plays a role of physical bombardment. The etching rate of TST films increases with the increasing concentration of CF4 in the gas mixture. The etching chamber pressure has less effect on the TST film etching speed, while the etching power has larger effect. The etch rate is up to 126 nm/min with the smooth etched surface(RMS=0.82 nm) and TST film profile is almost vertical(approaching 90°) using optimized etching parameters, including the total flow rate of 50 sccm, CF4 concentration of 26%, power of 400 W and pressure of 13.3 Pa.

This paper mainly discusses the system design and establishes the experimental system which conducts realtime off-axis measurement of the human eye’s aberration. The target is installed in the optical path of human eye objective measuring system. When observing the target, the human eye adjusts itself to a relaxing state so as to conduct measurement. The target being observed conducts movement vertical to optical axis within its field range, and then realized the off-axis aberration measurement. Research data show that only when normal incidence of the light occurs can changes the human eye’s aberration which caused by measuring errors be minimized. Data from all the objects reveal that second order aberration has the largest proportion among all the aberrations and does not show significant change within the increased off-axis angle in the vision field. Third order aberration increases with the increase of off-axis angle in the vision field. Fourth order aberration shows no obvious increase except the first item. High order aberrations for fifth order and above do not change much with the increase in off-axis angle in the field range. Meanwhile, the proportion of fifth order or above aberrations is the smallest among all the objects’ aberrations. The study results demonstrate that it is the aberrations of the former four orders that have a significant affect on human eye. With regard to off-axis aberration, third order and fourth order affect human eye imaging quality significantly. On the contrary, the high order aberrations of fifth order and above have a minor influence on human eye imaging quality.

The Liou-Brennan eye model is constructed using the optical design software ZEMAX.The Depth of Focus(DOF),extended Intraocular Lenses(IOL) that includes aspherical IOL,refractive multifocal IOL and diffractive multifocus IOL are included in the design.The optical performance of the pseudophakic eye for the designed IOLs is analyzed for both the spot diagram and visual acuity.For the pseudophakic eye with a 3 mm pupil,when the spherical aberration is fully corrected by the aspherical IOL,the best visual acuity reaches 1.2 with a DOF of only 1.4 m-1.When the spherical aberration is 0.4λ,the best visual acuity is 0.9 with a DOF as high as 2.2 m-1.With the implantation of refractive or diffractive multifocus IOLs,the pseudophakic eye has fairly good distant and near vision,while the intermediate vision is lower than 0.5.Diffractive multifocal IOL allows 81% input energy to image and the energy distribution is not affected by the pupil size.The energy distribution of the refractive multifocal IOL is dependent on the pupil diameter.The aspherical IOL,refractive multifocal IOL and diffractive multifocal IOL can extend DOF after surgery.However,they all have advantages and disadvantages,which should be taken into consideration under clinical conditions.

The spectra of Light Emitting Diode(LEDs) with different colors and powers are measured with a photometric,chromatic and electric characteristic analyzer,and then a new model consisted of several Gaussian distribution functions is used to represent the spectra of LED.Meanwhile,the model coefficients are calculated through the LED spectra in a rated current.It is shown that an expression with 3n Gaussian distribution functions is proper to represent the LED′s spectrum of n peaks.The errors between the established model and the actual spectra of high power LEDs of red,yellow,blue,green and white color are 3.45%,1.01%,2.33%,4.65% and 2.49%,respectively.For the low-power LEDs,the errors are 2.61%,2.65%,3.77%,2.87% and 2.48%,respectively.Compared with the reported models,the established model has characteristics of high precision and good universality.This study is very important to design the photometric,chromatic instruments or the intelligent products of LEDs.

National Integrate Circuit Research Program of China [2009ZX02023-3]; National Basic Research Program of China [2007CB935400, 2010CB934300, 2006CB302700]; National High Technology Development Program of China [2008AA031402]; Science and Technology Council

A novel method to determine the junction temperature of GaN type blue light LED based on the spectral parameters is proposed. In this method, the relationships among LED junction temperature, centroid wavelength and FWHM are obtained in the lab, and then the junction temperature of operating LED of the same type can be derived from this relationship. A comparative analysis of the junction temperatures which are measured with the centroid wavelength-FWHM method and with the forward voltage method is performed. The standard deviation between these two methods is found to be about 2.3[Formula: see text]C. Therefore, the combination of centroid wavelength and FWHM can be used to determine the junction temperature of GaN-based blue LED.

The fractal square $F$ is defined by $F=\frac{1}{n}(F+\mathcal{D})$, where $\mathcal{D}=\{d_{1},d_{2},\ldots,d_{m}\}\subseteq\{0,1,\ldots,n-1\}^{2},~$ $n\geq~2$. In this paper, we study the structure of two non-totally disconnected fractal squares in the case $m=6$, $n=3$ and construct a map between them. Using finite state automaton, we prove that this map is a bi-Lipschitz map.

We report the experimental phenomenon of large resistance change in plasma oxidized TiOx/TiNx film fabricated on W bottom-electrode-contact (W-BEC) array. The W-BEC in diameter 260?nm is fabricated by a 0.18??m CMOS technology, and the TiOx/TiNx cell array is formed by rf magnetron sputtering and reactive ion etching. In current?voltage (I?V) measurement for current-sweeping mode, large snap-back of voltage is observed, which indicates that the sample changes from high-resistance state (HRS) to low-resistance state (LRS). In the I?V measurement for voltage-sweeping mode, large current collapse is observed, which indicates that the sample changes from LRS to HRS. The current difference between HRS and LRS is about two orders. The threshold current and voltage for the resistance change is about 5.0?10?5?A and 2.5?V, respectively. The pulse voltage can also change the resistance and the pulse time is as shorter as 30?ns for the resistance change. These properties of TiOx/TiNx film are comparable to that of conventional phase-change material, which makes it possible for RRAM application.

A phase change memory cell based on Ge0.5Sb2Te3/Ti0.6Sb2Te3 double-layer structure is proposed for 3-level storage. The fabricated cell can realize 3-level storage ability by both current and voltage operation. Cycling ability has been proved better than 2×103. Thermal simulation shows that the resistivity difference between the two materials can greatly affect the temperature distribution in the cell. More heat will be generated in the amorphous Ge Ge0.5Sb2Te3/ film when the current flow through due to the higher resistivity. And the lower crystallization temperature of Ge0.5Sb2Te3/compared to that of Ti0.6Sb2Te3 ensures its priority of crystallization, which makes the 3-level storage feasible.

A novel phase change material, Si 2 Sb 2 Te 3 has been reported to show good phase change abilities. Etching of this material is a critical step in the fabrication of phase change memory devices. In this paper, the characteristics of Si 2 Sb 2 Te 3 etched in CF 4 /Ar atmosphere are investigated. The influence of the etching rate and surface roughness with different CF 4 /Ar ratio, pressure, and power are systematically studied. Furthermore, our X-ray photoelectron spectroscopy test results show that Te is the bottleneck to accelerating the etching rate.

Novel Si3.5Sb2Te3 phase change material for phase change memory is prepared by sputtering of Si and Sb2Te3 alloy targets. Crystalline Si3.5Sb2Te3 is a stable composite material consisting of amorphous Si and crystalline Sb2Te3, without separated Te phase. The thermally stable Si3.5Sb2Te3 material has data retention ability (10 years at 412K) better than that of the Ge2Sb2Te5 material (10 years at 383 K). Phase change memory device based on Si3.5Sb2Te3 is successfully fabricated, showing low power consumption. Up to 2.2 × 107 cycles of endurance have been achieved with a resistance ratio lager than 300.