Assessment of land use change of ecological green wedge and cooling island effect: A case study of Wuhan, China.

The construction of urban ecological green wedges, which can mitigate the heat island effect through cooling and ventilation effects, is an important way to enhance the adaptation of cities to climate change. Dynamic monitoring and periodic assessment of both the conservation status and cooling effect of ecological green wedges is a key to ensure the heat mitigation benefits. Based on multi-source remote sensing data, we systematically analyzed the land use changes of six ecological green wedges in Wuhan in 2013 and 2020 using the methods of Markov transfer matrix, land use dynamics, and comprehensive index of land use degree, and evaluated the changes in surface temperature of the ecological green wedges and their cooling island effect. Results showed that the ecological green wedges in Wuhan generally had a large amount of construction land encroaching on ecological land from 2013 to 2020, with the water decreased the most. With the continuous deterioration of ecological green wedges, their land surface temperatures showed rising trends, together with significant weakening trends in cooling island effects. Among all the six wedges, the Dadonghu, Tangxun, and Wuhu exhibited relatively better ecological conservation, slighter land use change and lower overall development degree. Qinglinghu and Houguanhu demonstrated average levels of conservation. Fuhe experienced the most severe change under the significant influence of the westward policy of Wuhan City, with the proportion of water decreasing by 7.1%, warming up by 3.00 ℃, and the largest reduction in cooling distance for the cooling island effect, amounting to about 210 m. The results provided scientific evidence for the urban heat island mitigation-oriented planning and management of ecological green wedges for Wuhan City.

Cadaveric comparison of two facial flap-harvesting techniques for alloplastic facial transplantation.

BACKGROUND: Functional and aesthetic reconstruction of severe facial deformities presents a major challenge, and the results are rarely satisfactory. Recent clinical success of composite tissue allograft transplantation and improvements in autoimmune regulation have initiated efforts to reconstruct severe facial deformities with alloplastic tissue. Few reports address the full facial flap dissection approach, where lengthy procedural times remain a limiting factor in achieving optimal graft survival. Extensive vascular anastomoses within facial tissues provide a unique opportunity to explore alternative graft harvesting strategies to optimise operative ischaemia. OBJECTIVE: The aim of the study was to shorten donor-graft harvesting time and reduce warm ischaemia. We evaluated alternative facial harvesting strategies through mock cadaveric facial transplantations. METHODS: Cadaveric dissections were performed to explore facial-scalp reconstruction alternatives. Six paired sub-superficial muscloaponeurotic system (SMAS) plane composite facial-scalp flaps were harvested using either a superficial temporal artery (STA) or a facial artery (FA) pedicle technique (Group I) or an external carotid artery (ECA) pedicle technique. Total harvesting times and lengths of vascular pedicles were measured. RESULTS: Harvesting time for a STA and FA pedicle total facial flap (mean=113min, range = 105-120 min, SD = 6 min) was shorter than that for an ECA pedicle flap (mean = 232 min, range = 225-240 min, SD = 6 min) (P<0.01). Mean pedicle lengths for the STA, the FA, the ECA, the external jugular vein, and the facial vein were 37 +/- 2.1, 35 +/- 1.8, 26 +/- 1.4, 52 +/- 3.0 and 42 +/- 2.6mm, respectively. Mean pedicle lengths for the supraorbital, supratrochlear, infraorbital, mental, and facial nerve were 15 +/- 1.5, 14 +/- 1.4, 24 +/- 1.2, 30 +/- 1.6 and 32 +/- 1.8mm, respectively. CONCLUSION: Compared with previously reported ECA pedicle total facial allograft harvesting techniques, an STA and FA pedicle flap provides a shorter harvesting time and potentially safer dissection method for facial transplantation by avoiding interference with the complicated anatomy of the carotid and submental triangle. Early graft ischaemic damage can be minimised by this harvesting technique, which significantly shortens harvesting time compared with previously described approaches, while maintaining adequate full facial perfusion.

[Anatomic study of supratrochlear artery and its application in nasal reconstruction].

OBJECTIVE: To study the anatomy of the cutaneous branch (CB) of supratrochlear artery and its relevance to the design of frontal flap in nasal reconstruction. METHODS: 10 fresh cadavers were dissected to study the position and course of the CB of supratrochlear artery (supraorbital rim and facial midline as landmark). The communication between the CB and supraorbital artery was also studied. 5 cases of ultra-thin frontal flaps and 11 cases of bi-flap( cutaneous flap and muscular flap) were designed on anatomic basis. The survival rate of flap, the stability and aesthetic appearance of the reconstructed nose were followed up. RESULTS: The supratrochlear artery gave off constant CB (1.18 +/- 0.36) cm from upper orbital rim and (1.35 +/- 0.34) cm from the midline of face. The CB passed in a subcutaneous plane and communicated with the bilateral muscular branch, CB of the opposite side and bilateral supraorbital artery. The supratrochlear artery only had CB with no muscular branch in 3 cases. All the flaps survived completely except one with blister on the nose tip which healed spontaneously. The postoperative aesthetic appearance was very satisfactory. CONCLUSIONS: The supratrochlear artery has constant CB. The frontal ultra-thin flap pedicled with the CB can improve the therapeutic effect of nasal reconstruction.

[Strategy study of harvesting total facial flap and donor choice for allograft transplantation in cadaver].

OBJECTIVE: To explore the operational strategy of harvesting total facial allograft by autopsy. METHODS: Twelve fresh human cadavers were dissected. They were divided into two groups randomly. The total facial-scalp flap of the group I was elevated by the bi-pedicle method, the group II was operated with single-pedicle method. Both were dissected at the deep plane of the SMAS. : the time of facial flap harvesting, length of the artery vein and nerve pedicles of the donor were measured and marked, after operation, in each group we transferred one facial allograft to another. Then the free graft of group I was poured through artery by methylthioninium chloride to study vascular territories. RESULTS: Mean harvesting time of the group I (46 +/- 11) minutes, group II (111 +/- 7) minutes, P < 0.01. Perfusion result shows that unilateral superficial temporal artery and the opposite side of the facial artery can supply blood for whole face. The pedicle was long enough for anastomosis. Post-operation appearance: the face looks like neither the donor nor the recipient primarily, It's mainly due to the characteristics of the skeleton and the soft tissues. CONCLUSIONS: The bi-pedicle method of the harvesting total facial allograft is concise, fast, safe can be widely applied in clinical.

[Research of the preservation of the composite facial allograft].

OBJECTIVE: To investigate the effective method of preserving composite facial allograft so as to attenuate ischemic injury. METHODS: The composite facial allografts were harvested from dog, perfused and preserved with 4 degrees C physiological sodium chloride and UW solution respectively. Immediately after the removal of the flap, after 12, 24, 48 h of preservation, MTT assay was used to determine the viability of several kinds of tissue, including skin, mucosa, muscle, bleed vessel, nerve and gland. The results of the two groups were compared in term of viability percentage. The pathology of several tissues were observed after 24 and 48 h of storage. RESULTS: The viability percentage of every tissue conserved in UW solution for 48 hours was more than 75%. There was significant difference between physiological sodium chloride group and UW group (P < 0.05). Some changes, including Porous arrangement of fibers in connective tissue of skin and mucosa, hyalinization of tissue around the hair follicle and edema of cell in hair follicle, enlargement of space between muscle bundles and unclearness of boundary of acinus could be seen in physiological sodium chloride group while no significant change in UW group. CONCLUSIONS: UW solution could be considered as preservation solution for composite facial allograft.

[Establishment of composite facial and scalp allograft transplantation model in canine].

OBJECTIVE: To develop an experimental model of composite facial and scalp allograft in canine in order to investigate technical and immunological aspects and functional recovery of facial muscles of this new approach to facial reconstruction. METHODS: (1) Anatomic study: Four mongrel dogs were used for anatomical dissection of the head and neck region and for harvesting flap experiment. (2) Autologous transplantation (group I): Three types composite facial and scalp autologous transplantation were performed in five mongrel dogs. Type I composite tissue flap (group I a n = 2) included bilateral external ear and orbicularis oculi muscle. Type II (group I b n = 1) included single-lateral external ear, orbicularis oculi muscle, external nose upper and lower lip. Type III (group I c n = 2) included single - lateral external ear and orbicularis oculi muscle. (3) Allograft transplantation (group II): In group II a (n = 2), two allograft transplantation were performed with type III composite facial and scalp . In group II b (n = 4), four allograft transplantation were performed with the modified type III composite facial and scalp which included single - lateral external ear, orbicularis oculi muscle and one third of inferior tarsal plate and palpebral conjunctiva. To prevent allograft rejection, Cyclosporin A (CsA) and Methylprednisolone (MP) or Prednisone (PS ) were combined used as immunosuppressive protocol . Dose of CsA was adjusted depending on its blood drug level. Electromyogram (EMG) of orbicularis oculi muscle was carried out at 4 weeks, 6 weeks, 12 weeks and 6 months postoperation. RESULTS: (1) The facial anatomic characteristic of dog is similar to that of human being, external carotid artery and external jugular vein afford good blood supply to composite facial and scalp. (2) The dogs in group I c were long-term surviving with leakage of salivary juice. (3) In group II a (n = 2), one dog presented rejection reaction at 28th day postoperation, the reversal of rejection was achieved by increasing the dose of CsA and prednisone and with topical clobetasol for 2 weeks, the dog survived indefinitely( > 309 days). In group II b (n = 4), there were three dogs survived indefinitely ( > 159 days, > 129 days, > 108 days) without complication, EMG showed the function of orbicularis oculi muscle was gradually improving. CONCLUSION: The modified type III composite facial and scalp allograft transplantation model is an ideal model for facial allograft transplantation study.