A Full-Spectrum Registration Method for Zhuhai-1 Satellite Hyperspectral Imagery.

Accurate registration is an essential prerequisite for analysis and applications involving remote sensing imagery. It is usually difficult to extract enough matching points for inter-band registration in hyperspectral imagery due to the different spectral responses for land features in different image bands. This is especially true for non-adjacent bands. The inconsistency in geometric distortion caused by topographic relief also makes it inappropriate to use a single affine transformation relationship for the geometric transformation of the entire image. Currently, accurate registration between spectral bands of Zhuhai-1 satellite hyperspectral imagery remains challenging. In this paper, a full-spectrum registration method was proposed to address this problem. The method combines the transfer strategy based on the affine transformation relationship between adjacent spectrums with the differential correction from dense Delaunay triangulation. Firstly, the scale-invariant feature transform (SIFT) extraction method was used to extract and match feature points of adjacent bands. The RANdom SAmple Consensus (RANSAC) algorithm and the least square method is then used to eliminate mismatching point pairs to obtain fine matching point pairs. Secondly, a dense Delaunay triangulation was constructed based on fine matching point pairs. The affine transformation relation for non-adjacent bands was established for each triangle using the affine transformation relation transfer strategy. Finally, the affine transformation relation was used to perform differential correction for each triangle. Three Zhuhai-1 satellite hyperspectral images covering different terrains were used as experiment data. The evaluation results showed that the adjacent band registration accuracy ranged from 0.2 to 0.6 pixels. The structural similarity measure and cosine similarity measure between non-adjacent bands were both greater than 0.80. Moreover, the full-spectrum registration accuracy was less than 1 pixel. These registration results can meet the needs of Zhuhai-1 hyperspectral imagery applications in various fields.

Establishment and Clinical Application of the Concept of Invalid Extraction Rates in Follicular Unit Extraction.

OBJECTIVE: This study aims to establish the concept of invalid extraction rates in follicular unit extraction and evaluate its clinical value. METHODS: The present study involved 30 patients with alopecia. Three young surgeons (nominated A, B, and C) each performed follicular unit extraction on a randomly selected portion of the donor site of each patient for ten minutes. The outcomes were separately recorded and calculated, and converted to an invalid extraction rate for each surgeon using the formula, "invalid extraction rate = 1 - successfully extracted follicular units/actually extracted units × 100%." RESULTS: The follicular unit invalid extraction efficiency of each surgeon gradually declined. The average efficiency level of surgeon B was evaluated as excellent, while the levels of surgeons A and C were evaluated as good. CONCLUSION: With experience, surgeons can speed up the process of follicular unit extraction and gradually increase performance quality through both extraction speed and success rate.

Assessment of urban environmental change using multi-source remote sensing time series (2000-2016): A comparative analysis in selected megacities in Eurasia.

Excessive urban growth has led to an urban environmental degradation in megacities in less developed countries. Using fine particulate matter (PM2.5) concentration, land surface temperature (LST), and normalized difference vegetation index (NDVI) data obtained by satellite remote sensing, we analysed the inter-annual variations and trends in the urban environment of 17 megacities in Eurasia from 2000 to 2016. Taking the average environmental condition for all the megacities in 2000 as the baseline, the urban environmental conditions were evaluated by a Comprehensive Environmental Index (CEI) from 2001 to 2016. The variation and trends analysis of CEI revealed that the overall environmental conditions in Chennai, Dhaka, Kolkata and Tianjin showed significant deterioration trends. Environmental qualities in newly developed urban areas experienced degradation in Bangalore, Beijing, and Mumbai. The area of environmentally deteriorated urban land has been expanding in Bangalore, Chennai, Delhi, Kolkata, and Mumbai in India and Dhaka in Bangladesh since 2001. By contrast, the area of environmentally degraded urban land in Chinese megacities expanded to the largest extent in the period of 2007-2009 and decreased afterwards. The result suggests that greening and strong emission control strategies significantly contributed to urban environmental quality enhancement in rapidly developing megacities.

[Establishment of an in vitro culture model of single human hair follicle].

OBJECTIVE: To establish an in vitro culture model of single human hair follicle, and observe their morphological and histological changes. METHODS: Human hair follicles were isolated from the volunteer patients. After dissecting follicles into single, follicles in growth phase were cultured in Williams E without any serum. This experiment included 3 groups: single follicle without sebaceous gland and other surrounding tissue (control group); single follicle with sebaceous gland and without the other surrounding tissue( experiment group A); single follicles with sebaceous gland and the other surrounding tissue (experiment group B). The survival rate, survival time, growth rate, multiplication capacity and apoptosis of cultured follicles and their morphological and histological changes were observed sequentially. RESULTS: The hair follicles in experiment groups showed a better viability and a higher growth rate than those in control group. And the follicles in group B could keep growing for more than 25 days, which was longer than those in group A. Moreover, the sebaceous gland and the other surrounding tissue in group B showed great induction effect on follicle-cell proliferation and anti-apoptosis. CONCLUSION: The in vitro culture model of signal human hair follicles (single follicles including epidermis, sebaceous gland and the other surrounding tissue) had optimized internal environment which is similar to in vivo internal environment.

Reconstruction of large unilateral hemi-facial scar contractures with supercharged expanded forehead flaps based on the anterofrontal superficial temporal vessels.

BACKGROUND: The expanded forehead flap, using temporal pedicles, has been employed extensively in facial reconstruction. To overcome the disadvantages of the traditional dual temporal pedicles, such as the limited transfer range and the short length of the flap, the distal supercharging technique can be applied to lengthen the flap and extend the transfer range, especially in the cases with a past temporal burn injury. This article aims to present an application of the distal supercharged expanded forehead flap procedure for hemi-facial reconstruction and discuss the haemodynamics of the expanded forehead flap. METHODS: The tissue expander implantation and the following forehead tissue expansion were performed regularly. When the forehead skin expansion was completed, an expanded forehead flap was created and transferred to the damaged facial area with one distal temporal vessel pedicle that was anastomosed with facial vessels in a supercharged way. All patients were analysed retrospectively. RESULTS: From September 2009 to September 2011, eight male patients and one female patient were treated using this method. Their flaps size ranged from 20 cm × 8 cm to 30 cm × 11 cm and no flap loss occurred. Patients came in for follow-ups 9-16 months after the procedures. All the patients were satisfied with the results. CONCLUSIONS: The supercharging expanded forehead flap procedure can provide reliable flap vascularity due to its elastic transferring abilities. By using a distal supercharging technique, we can lengthen and widen the flap to tailor it to the defect, while also minimising the donor defect in the patients with a past temporal injury.

Inverted 'V--Y' advancement medial epicanthoplasty.

The presence of an epicanthal fold is a distinctive anatomic feature of the Asian population. Epicanthoplasty can be very helpful in resolving the above problematic anatomy and may produce a more aesthetic appearance. The goal of this report is to describe a modification in the traditional operative methods related to medial epicanthoplasty, to minimise scar appearance and maximise normal appearance. An inverse triangular flap of skin is based on the semilunar skin, which is elevated and retracted within the line of the normal eyelid. The design of four key points is crucial to this epicanthoplasty. A total of 62 patients were performed with this method; 42 of this group underwent simultaneous double-eyelid plasty. Most of the patients obtained satisfactory results aesthetically followed from 6 months to 4 years postoperation. There was no recurrence of the epicanthal fold. As many as 38 patients were followed by interview and photographs were taken at the same time. The rest of the patients were followed up through telephone. No patients complained about visible scarring in the epicanthal area. As many as 60 patients obtained satisfactory results aesthetically, two patients complained about the median canthal asymmetry. The result indicates the reliability and feasibility of epicanthoplasty.

[Experimental study on culturing dermal papillae cells with keratinocyte medium].

OBJECTIVE: Dermal papillae cells are widely applied to reconstruction of tissue engineered hair follicle and skin. To investigate the difference of the biological characteristics of dermal papillae cells cultured with keratinocyte medium (KM) and normal medium (NM), and to determine whether it is feasible for the reconstruction of tissue engineered hair follicle using dermal papillae cells cultured in KM. METHODS: Scalp samples were obtained in rhytidectomy procedure. Dermal papillae were isolated by two steps digestive treatment, then cultured with KM and NM in two groups. The time of dermal papillae adherence and cell outgrowth was recorded and the rate of dermal papillae adherence was determined after 5 days. As well as, the difference of cell morphology was observed through inverted phase contrast microscope. The maximum generations were determined in two groups and the cell sheets were observed by HE staining. In third-generation cells, the number of aggregates in every dish and the proliferation by MTT were compared between two groups. Meanwhile, the expression of a-smooth muscle actin (alpha-SMA) and ALP were detected by immunofluorescence and specific staining in two groups. RESULTS: Dermal papillae of KM group had a higher rate of adherence and fast outgrowth. The rates of adherence were 54.17% and 36.78% in KM group and in NM group, respectively. In KM group, cells adhered after 24 hours and outgrew after 64 hours. While, cells adhered after 48 hours and outgrew after 80 hours in NM group. The cells were bigger in NM group than in KM group. In third-generation cells, 3.06 +/- 1.12 and 9.25 +/- 1.73 aggregates formed in NM group and KM group, respectively, the difference was significant (P < 0.05). In addition, cells could form cell sheets which were muti-layers in KM group. Mostly 7 and 15 generations could been subcultured in NM group and KM group, respectively. The result of MTT indicated that cells proliferated more actively in KM group; absorbance value of KM group was significantly higher than that of NM group after 7 days (P < 0.05). The positive of alpha-SMA were detected in the third-generation cells of both groups. Occasionally a little few cells expressed ALP with (987 +/- 146) microm2 positive area in the sixth-generation cells of NM group. However, the cells still expressed ALP with (8 757 +/- 558) microm2 positive area in the fourteenth-generation cells of KM group and the difference was significant (P < 0.05). CONCLUSION: Cells proliferate actively and aggregate obviously and could been subcultured more generations in KM. Therefore, culturing dermal papillae cells with KM is feasible for the reconstruction of tissue engineered hair follicle.