Analysis of factors affecting delay accuracy of subfemtosecond liquid crystal variable retarders.

To obtain a wide range of high-precision time-delay controllable devices, a 100-µm-thick nematic liquid crystal (LC) cell was fabricated using the LC HTD028200-200. Factors influencing the delay calibration accuracy of LC variable retarders (LCVRs) were analyzed theoretically and experimentally. Subsequently, within the total voltage tuning range of 0-5 V, the LCVR had a delay of 4.977-97.404 fs, total delay range of 90 fs, tuning accuracy of ±0.216fs, and tuning resolution of 0.128 fs. This device will play an important role in spectral imaging.

Ambient Airborne Particulates of Diameter ≤1 µm, a Leading Contributor to the Association Between Ambient Airborne Particulates of Diameter ≤2.5 µm and Children's Blood Pressure.

Evidence on the associations between airborne particulates of diameter ≤1 µm (PM1) and airborne particulates of diameter ≤2.5 µm (PM2.5) and childhood blood pressure (BP) is scarce. To help to address this literature gap, we conducted a study to explore the associations in Chinese children. Between 2012 and 2013, we recruited 9354 children, aged 5 to 17 years, from 62 schools in 7 northeastern Chinese cities. We measured their BP with a mercury sphygmomanometer. We used a spatiotemporal model to estimate daily ambient PM1 and PM2.5 exposures, which we assigned to participants' home addresses. Associations between particulate matter exposure and BP were evaluated with generalized linear mixed regression models. The findings indicated that exposure to each 10 mg/m3 greater PM1 was significantly associated with 2.56 mm Hg (95% CI, 1.47-3.65) higher systolic BP and 61% greater odds for hypertension (odds ratio=1.61 [95% CI, 1.18-2.18]). PM1 appears to play an important role in associations reported between PM2.5 exposure and BP, and we found that the ambient PM1/PM2.5 ratio (range, 0.80-0.96) was associated with BP and with hypertension. Age and body weight modified associations between air pollutants and BP (P<0.01), with stronger associations among younger (aged ≤11 years) and overweight/obese children. This study provides the first evidence that long-term exposure to PM1 is associated with hypertension in children, and that PM1 might be a leading contributor to the hypertensive effect of PM2.5. Researchers and policy makers should pay closer attention to the potential health impacts of PM1.

A New Absorbable Synthetic Substitute With Biomimetic Design for Dural Tissue Repair.

Dural repair products are evolving from animal tissue-derived materials to synthetic materials as well as from inert to absorbable features; most of them lack functional and structural characteristics compared with the natural dura mater. In the present study, we evaluated the properties and tissue repair performance of a new dural repair product with biomimetic design. The biomimetic patch exhibits unique three-dimensional nonwoven microfiber structure with good mechanical strength and biocompatibility. The animal study showed that the biomimetic patch and commercially synthetic material group presented new subdural regeneration at 90 days, with low level inflammatory response and minimal to no adhesion formation detected at each stage. In the biological material group, no new subdural regeneration was observed and severe adhesion between the implant and the cortex occurred at each stage. In clinical case study, there was no cerebrospinal fluid leakage, and all the postoperation observations were normal. The biomimetic structure and proper rate of degradation of the new absorbable dura substitute can guide the meaningful reconstruction of the dura mater, which may provide a novel approach for dural defect repair.

High throughput miniature drug-screening platform using bioprinting technology.

In the pharmaceutical industry, new drugs are tested to find appropriate compounds for therapeutic purposes for contemporary diseases. Unfortunately, novel compounds emerge at expensive prices and current target evaluation processes have limited throughput, thus leading to an increase of cost and time for drug development. This work shows the development of the novel inkjet-based deposition method for assembling a miniature drug-screening platform, which can realistically and inexpensively evaluate biochemical reactions in a picoliter-scale volume at a high speed rate. As proof of concept, applying a modified Hewlett Packard model 5360 compact disc printer, green fluorescent protein expressing Escherichia coli cells along with alginate gel solution have been arrayed on a coverslip chip under a repeatable volume of 180% ± 26% picoliters per droplet; subsequently, different antibiotic droplets were patterned on the spots of cells to evaluate the inhibition of bacteria for antibiotic screening. The proposed platform was compared to the current screening process, validating its effectiveness. The viability and basic function of the printed cells were evaluated, resulting in cell viability above 98% and insignificant or no DNA damage to human kidney cells transfected. Based on the reduction of investment and compound volume used by this platform, this technique has the potential to improve the actual drug discovery process at its target evaluation stage.

Physically facilitating drug-delivery systems.

Facilitated/modulated drug-delivery systems have emerged as a possible solution for delivery of drugs of interest to pre-allocated sites at predetermined doses for predefined periods of time. Over the past decade, the use of different physical methods and mechanisms to mediate drug release and delivery has grown significantly. This emerging area of research has important implications for development of new therapeutic drugs for efficient treatments. This review aims to introduce and describe different modalities of physically facilitating drug-delivery systems that are currently in use for cancer and other diseases therapy. In particular, delivery methods based on ultrasound, electrical, magnetic and photo modulations are highlighted. Current uses and areas of improvement for these different physically facilitating drug-delivery systems are discussed. Furthermore, the main advantages and drawbacks of these technologies reviewed are compared. The review ends with a speculative viewpoint of how research is expected to evolve in the upcoming years.

Direct assembling methodologies for high-throughput bioscreening.

Over the last few decades, high-throughput (HT) bioscreening, a technique that allows rapid screening of biochemical compound libraries against biological targets, has been widely used in drug discovery, stem cell research, development of new biomaterials, and genomics research. To achieve these ambitions, scaffold-free (or direct) assembly of biological entities of interest has become critical. Appropriate assembling methodologies are required to build an efficient HT bioscreening platform. The development of contact and non-contact assembling systems as a practical solution has been driven by a variety of essential attributes of the bioscreening system, such as miniaturization, high throughput, and high precision. The present article reviews recent progress on these assembling technologies utilized for the construction of HT bioscreening platforms.

Structural design for birefringent holey fiber with a beat length insensitive to wavelength.

By combination of two defect structures with positive and negative birefringence, we design a holey fiber with a beat length that is less sensitive to wavelength. The influence of different structural parameters on birefringence of holey fiber is calculated by the finite-difference beam propagation method. A stable beat length can be achieved at some given wavelength window by adjusting the parameters. An almost uniform beat length with a greater than 180 nm bandwidth at 1310 and 1550 nm wavelength windows is obtained, which is useful for the design and fabrication of fiber-optic wave plates with a wide band.

A new modified dura mater implant: characteristics in recipient dogs.

Duraplasty is critical to the maintenance of anatomical integrity and the protection of brain tissue. Allotransplantation of cadaveric dura mater was abandoned after it was found to transmit Creutzfeldt-Jakob disease (CJD). In this study, the usefulness of a xenogeneic dura mater for dural reconstruction was tested. Twelve dogs were randomly assigned to 4 groups. To simulate the condition of patients with brain surface injury, an area of approximately 2 cm x 1.5 cm of the dura mater was removed to create a defect. Xenogeneic dura mater derived from porcine pericardium was trimmed to the shape and size of the defect and sutured to the endogenous dura mater. Muscles at the apex of the skull and scalp were also sutured. Three dogs were euthanized at 3, 6, 9, and 12 months after implantation and the xenogeneic dura mater and surrounding endogenous tissue were examined macroscopically and microscopically. Three months after implantation, the graft site had begun to heal. Macroscopically, at 6, 9, and 12 months after implantation, the graft had healed completely with the surrounding tissue. No boundary between the graft and surrounding tissue was distinguishable, and the two could not be separated. The graft was smoothly epithelialized and nonadherent to the brain surface. Microscopically, the inner surface of the implant was covered with epithelial cells, and internal capillaries, subepithelial fibrous tissue deposition, and fibroblast proliferation were observed. The xenogeneic dura mater progressively degraded over time. No cysts and no neutrophilic or lymphocytic inflammatory cell response developed between the implant and the recipient brain parenchyma. The modified xenogeneic dura mater is sufficiently biocompatible to allow epithelialization of its inner surface without adherence to brain tissue. No abnormalities develop in recipients, and the xenograft is gradually biodegraded and replaced by endogenous tissue identical to the endogenous dura mater.