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Background We aimed to assess the safety and immunogenicity of an inactivated vaccine against COVID-19 in Chinese adults aged ≥18 years. Methods This is an ongoing randomized, double-blind, placebo-controlled, phase 1/2 clinical trial among healthy adults aged ≥18 years in Henan Province, China. Participants (n = 336 in 18–59 age group and n = 336 in ≥60 age group) were enrolled between April 12 and May 17 2020, and were equally randomized to receive vaccine or placebo (aluminum hydroxide adjuvant) in a three-dose schedule of 2·5, 5, or 10 µg on days 0, 28, and 56. Another 448 adults aged 18–59 years were equally allocated to four groups (a one-dose schedule of 10 µg, and two-dose schedules of 5 µg on days 0 and 14/21/28) and received vaccine or placebo (ratio 3:1 within each group). The primary outcomes were 7-day post-injection adverse reactions and neutralizing antibody titres on days 28 and 90 after the whole-course vaccination. Trial registration: www.chictr.org.cn #ChiCTR2000031809. Findings The 7-day adverse reactions occurred in 4·8% to 32·1% of the participants in various groups, and most adverse reactions were mild, transient, and self-limiting. Twenty participants reported 68 serious adverse events which were judged to be unrelated to the vaccine. The 90-day post-injection geometric mean titres of neutralizing antibody ranged between 87 (95% CI: 61–125) and 129 (99–169) for three-dose schedule among younger and older adults; 20 (14–27), 53 (38–75), and 44 (32–61) in 5 µg days 0 and 14/21/28 groups, respectively, and 7 (6–9) in one-dose 10 µg group. There were no detectable antibody responses in all placebo groups. Interpretation The inactivated vaccine against COVID-19 was well tolerated and immunogenic in both younger and older adults. The two-dose schedule of 5 µg on days 0 and 21/28 and three-dose schedules on days 0, 28, and 56 could be further evaluated for long-term safety and efficacy in the phase 3 trials. Funding The study was funded by the National Program on Key Research Project of China (2020YFC0842100) and Major Science and Technology Project of the National New Drug Development of China (2018ZX09734-004).

Background Extramammary Paget disease (EMPD) is an uncommon malignancy affecting apocrine gland–bearing skin, such as vulvar, perianal, axillary and penoscrotal areas. Paget cells are sometimes detected outside clinical border in a phenomenon called subclinical extension. Satellite is one of the patterns of subclinical extension which is likely to be invisible. The standard management strategy for EMPD without distant metastasis is a complete surgical removal, sometimes called wide local excision. However, there is no consensus regarding surgical margin width to decrease the high recurrence rate. Here we describe the first macroscopically visible satellite of axillary EMPD and wide local excision of both main lesion and the satellite lesion with only 0.5 cm margin, succeeded by a short review of the literature. Case presentation A 48-year-old female with a red macule in the right axilla was presented to our clinic. A well-demarcated 4 cm × 3 cm erythematous plaque was observed in the right axilla, and a similar lesion measuring 0.5 cm × 0.3 cm was found 3.5 cm away from the primary site. Breast and axillary node examination was unremarkable. Biopsy of the large plaque revealed Paget disease, then we performed a local extended excision of both lesions with a 0.5 cm margin, all margins negative indicated, by frozen pathology. Pathology revealed the nature of the satellite beside the main lesion also as Paget disease. The patient is currently followed-up for 20 months and has shown no signs of recurrence, with normal shoulder motor function. Conclusion We have report the first visible satellite of extramammary Paget disease, indicating the necessity of an extended local resection of both the main leision and the satellite lesion. Considering the anatomical structure of axillary Paget disease, a 0.5 cm negative surgical margin indicated by frozen pathology might be sufficient to sustain the shoulder motor function.

Importance A vaccine against coronavirus disease 2019 (COVID-19) is urgently needed. Objective To evaluate the safety and immunogenicity of an investigational inactivated whole-virus COVID-19 vaccine in China. Interventions In the phase 1 trial, 96 participants were assigned to 1 of the 3 dose groups (2.5, 5, and 10 μg/dose) and an aluminum hydroxide (alum) adjuvant-only group (n = 24 in each group), and received 3 intramuscular injections at days 0, 28, and 56. In the phase 2 trial, 224 adults were randomized to 5 μg/dose in 2 schedule groups (injections on days 0 and 14 [n = 84] vs alum only [n = 28], and days 0 and 21 [n = 84] vs alum only [n = 28]). Design, setting, and participants Interim analysis of ongoing randomized, double-blind, placebo-controlled, phase 1 and 2 clinical trials to assess an inactivated COVID-19 vaccine. The trials were conducted in Henan Province, China, among 96 (phase 1) and 224 (phase 2) healthy adults aged between 18 and 59 years. Study enrollment began on April 12, 2020. The interim analysis was conducted on June 16, 2020, and updated on July 27, 2020. Main outcomes and measures The primary safety outcome was the combined adverse reactions 7 days after each injection, and the primary immunogenicity outcome was neutralizing antibody response 14 days after the whole-course vaccination, which was measured by a 50% plaque reduction neutralization test against live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results Among 320 patients who were randomized (mean age, 42.8 years; 200 women [62.5%]), all completed the trial up to 28 days after the whole-course vaccination. The 7-day adverse reactions occurred in 3 (12.5%), 5 (20.8%), 4 (16.7%), and 6 (25.0%) patients in the alum only, low-dose, medium-dose, and high-dose groups, respectively, in the phase 1 trial; and in 5 (6.0%) and 4 (14.3%) patients who received injections on days 0 and 14 for vaccine and alum only, and 16 (19.0%) and 5 (17.9%) patients who received injections on days 0 and 21 for vaccine and alum only, respectively, in the phase 2 trial. The most common adverse reaction was injection site pain, followed by fever, which were mild and self-limiting; no serious adverse reactions were noted. The geometric mean titers of neutralizing antibodies in the low-, medium-, and high-dose groups at day 14 after 3 injections were 316 (95% CI, 218-457), 206 (95% CI, 123-343), and 297 (95% CI, 208-424), respectively, in the phase 1 trial, and were 121 (95% CI, 95-154) and 247 (95% CI, 176-345) at day 14 after 2 injections in participants receiving vaccine on days 0 and 14 and on days 0 and 21, respectively, in the phase 2 trial. There were no detectable antibody responses in all alum-only groups. Conclusions and relevance In this interim report of the phase 1 and phase 2 trials of an inactivated COVID-19 vaccine, patients had a low rate of adverse reactions and demonstrated immunogenicity; the study is ongoing. Efficacy and longer-term adverse event assessment will require phase 3 trials. Trial registration Chinese Clinical Trial Registry Identifier: ChiCTR2000031809.

In order to present the collapse process and failure mechanism of long-span cable-stayed bridges under strong seismic excitations, a rail-cum-road steel truss cable-stayed bridge was selected as engineering background, the collapse failure numerical model of the cable-stayed bridge was established based on the explicit dynamic finite element method (FEM), and the whole collapse process of the cable-stayed bridge was analyzed and studied with three different seismic waves acted in the horizontal longitudinal direction, respectively. It can be found from the numerical simulation analysis that the whole collapse failure process and failure modes of the cable-stayed bridge under three different seismic waves are similar. Furthermore, the piers and the main pylons are critical components contributing to the collapse of the cable-stayed bridge structure. However, the cables and the main girder are damaged owing to the failure of piers and main pylons during the whole structure collapse process, so the failure of cable and main girder components is not the main reason for the collapse of cable-stayed bridge. The analysis results can provide theoretical basis for collapse resistance design and the determination of critical damage components of long-span highway and railway cable-stayed bridges in the research of seismic vulnerability analysis.

Although Bi2S3 is one of the promising thermoelectric materials, its practical application is limited by a relatively low dimensionless figure of merit (ZT), and especially low electrical conductivity. In this work, ZnO was used to tune the thermal and electrical properties of Bi2S3. In the preparation processes of mechanical alloying (MA) and spark plasma sintering (SPS), small amounts of ZnO converted to ZnS in the sulfur rich environment, accompanied by the production of sulfur vacancies and micro/nanostructures. The sulfur vacancies increased the electrical conductivity of n-type Bi2S3 and micro/nanostructures scattered phonons without commonly deteriorating electronic transport. The maximum ZT value of 0.66 at 675 K for Bi2S3 doped with 1.0 mol% ZnO was obtained and the results of this work perhaps provide a new way for designing and fabricating thermoelectric materials.

Dracorhodin perchlorate (DP) is extracted from Dragon’s blood, which is widely used in traditional Chinese medicine, especially in wound healing. The aim of this paper is to investigate the influence of DP ointment, which contained DP dissolved in DMSO and mixed with Vaseline, on cutaneous wound healing in Wistar rats. Forty Wistar rats were divided into two groups: control and DP groups. The skin on the back of each rat was punched with two full-thickness wounds and then treated with the corresponding drug. After 3, 7, 10, 14, and 21 days, four rats were sacrificed for immunological, biochemical, and histological analyses. Compared with the control treatment, DP could significantly promote wound closure. Histological and biochemical analyses of the skin biopsies also showed that DP regulated the expression of inflammatory responses by TNF-α and IL-β and by supporting wound tissue growth and collagen deposition. Western blot revealed that DP could also facilitate the expression of EGF and VEGF proteins. In conclusion, DP promotes wound healing.

This paper reviews the research on the safety management of elderly patients with hypertension in the community in China and abroad. The research involves the concept of elderly hypertension and medication safety, the characteristics of patients with elderly hypertension in the community and some problems with the safety management of them in the community. Based on the above-mentioned research results, this paper draws a conclusion that community hypertensive patients must implement effective drug safety management measures and briefly puts forward some suggestions.

Based on the characteristics of the geometric control method during the construction of cable-stayed bridge, the key goal to complete the bridge is to ensure that the non-stress dimensions and profile of every component is constant. Because one of the key points to complete the cable-stayed bridge is to ensure that the non-stress length of the closure segments is constant, it is necessary to adjust the relative position of the final closure by the geometric closure method of incremental launching construction to satisfy the requirement of the non-stress length of the closure segments. Aimed at the critical technical problems existing in incremental launching construction process, taking Jiashao bridge as the research subject, the analysis of the incremental launching plan and the local stress of pushing bracket and bearing block are carried out. The research will provide scientific basis for the feasibility of geometric control incremental launching construction method and it will guarantee the smoothly incremental launching construction.

Taking Edong Yangtze River Bridge as the research subject, the influence of error of unstressed cable length on the geometric shape and internal force of super-span hybrid girder cable-stayed bridge during completion is studied on the basis of the geometry control method with full consideration of the structural nonlinear geometrical effect. Moreover, the mechanical behaviors of the center and side spans of the bridge and their control strategies are discussed. The analysis shows that structural differences between the center and side spans exerted an influence on the geometric shape and internal force. The influence of unstressed cable length error on the geometric shape in the center span of the completed bridge is greater than that of the side span, whereas the impact on internal force in the side span is greater than that in the center span. The mechanical behavior is relatively independent between span types. In addition, the percentage change of the girder stress reaches the maximum level in...

To accurately calculate the prestress of externally prestressed composite girder bridges, the six critical factors (the prestressing tendon withdrawal and anchor deformation, friction between prestressing tendon and deviator, prestressing tendon relaxation, concrete creep, concrete shrinkage and temperature changes) that cause the prestress loss of such type of the bridges are summarized and the corresponding simplified calculation methods are respectively derived on the basis of the existing researches. The prestressing tendons ability has an important influence on the mechanical behavior of prestressed composite girder bridges, which is the key design parameters. Prestress loss will occur in the process of long-term use, so that the whole beam stress redistribution occurs. How to accurately calculate the value of the prestressing loss is an issue of great concern to engineers. And at present there is few research for prestressed composite girder bridges. On the basis of existing research, this paper summarizes the key factors that lead to loss of prestress and derives the corresponding simplified calculation method for design reference.

This paper introduces the analysis of three span continuous girder arch bridge under the action of live load whose middle span is concrete filled steel tube with Ansys. Through the analysis, the deformation and the maximum displacement can be got which may provide reliable reference for further study of the arch bridge.

In the construction process of Hong Kong-Zhuhai-Macao Bridge, the side span girder of Qingzhou channel bridge, the non-navigable span of the shallow water region and the side span S11 ~ S17 large segments are located between transitional pier and auxiliary pier of Jiuzhou channel bridge are based on the large segment hoisting construction technique. The widely use of the large segment hoisting construction which can ensure the construction safety and shorten the construction period obviously, effectively reduce the bad environment factors in construction. All of these are important to the transportation hub, Hong Kong-Zhuhai-Macao Bridge. But because of the transformation of structural system and the complex stress of the large segment girder in the lifting point in transportation and hoisting process, it is significant to do the finite element simulation analysis.

In order to satisfy the requirement of the underwater acoustic positioning system for offshore oil exploration, a design idea for water surface communication system of ultra short base line (USBL) positioning system. The main function of this design is to achieve high-quality communication with underwater acoustic responders. The hardware adopted JZ4760 and the FPGA of altera as the cores. Gold sequence direct sequence spread-spectrum was used on communication system, while modulation was PSK. An appropriate spread-spectrum synchronization mode was presented for the system. MATLAB-based simulation and experiments show that the system is working reliably.

Face recognition continues to be a hot topic in pattern recognition and computer vision recent years. Meantime, sparse representation is a new technique utilizing compressed sensing method applied in pattern recognition research recent years. This paper comparison with PCA and SP for face recognition, makes some improvement on great performance eigenface algorithm, using sparse representation with eigenface space to achieved better result. Finally, the proposed algorithm based on eigenface sparse recognition shows that of better result.

In order to satisfy the requirement of the underwater acoustic positioning system for offshore oil exploration, a design idea for an underwater acoustic responder which used on USBL positioning system was proposed. The hardware adopted MSP430F5438 as the core of controlling and the digital signal processor TMS320VC5509A for computing, and made a detailed analysis for the low-power hardware design. Gold sequence direct sequence spread-spectrum was used on communication system, while modulation was PSK. An appropriate spread-spectrum synchronization mode was presented for the system. MATLAB-based simulation and experiments show that the responder is working reliably and supporting multi-user communication. Meanwhile, the standby quiescent current is less than 2 mA.

Multivariable non-square system with time delays often arises in the chemical production process. Owing to the matrix that is adopted to describe non-square system is not square, many classical multivariable control methods can be hardly applied in such system. In this paper, based on Non-square effective relative gain (NERGA) a novel decentralized PID control method is proposed. The input and output loops of the non-square system are paired though NERGA firstly, and then strong robust decentralized multivariable proportional-integral-differential (PID) controllers are designed individually based on the squared models. Finally, Simulation study was carried out for three inputs and two outputs system, the simulation results can demonstrate the effectiveness of the proposed method.

Silver (Ag) nanowires with different diameters (28, 38, 55, 80, 200 nm) have been successfully fabricated into the anodic alumina membranes (AAMs) by direct-current electrochemical deposition technique. X-ray diffraction and selected area electron diffraction analysis show that the as-synthesized samples have preferred (220) orientation independent of the nanowire diameters. Transmission electron microscopy and field-emission scanning electron microscopy investigation reveal that the large-area and highly ordered Ag nanowire arrays with smooth surface and uniform diameter are synthesized, and they have the high aspect ratio. The formation mechanism of the silver nanowires is also discussed. The nanowire arrays with different diameters may have potential applications in the future nanodevices.

ZnS nanowire arrays have been prepared for the first time by direct-current electrodeposition into the nanopores of porous anodic alumina membranes (AAMs), and the growth mechanism is that metal cations are firstly reduced and then react with elemental S to form ZnS nanowire arrays in the nanopores of AAMs. The nanopores of AAMs are of benefit to the formation of sulfide nanowires.

Ag nanowires with a graded diameter in anodic aluminum oxide (AAO) membranes were fabricated by the direct-current electrodeposition. The Ag nanowires have a graded-change in diameter from 8 to 32 nm, which is matched with the graded-change of the AAO pore diameter. Electronic transport measurements show that there is a transport behavior similar to that of a metal–semiconductor junction along the axial direction in the diameter-graded Ag nanowires. Such a novel homogeneous nanojunction will be of great fundamental and practical significance.

A review of the literature and a combined burn center study of the University of Beijing and the University of Colorado Health Sciences Center looking at cancer arising from old burn injuries are reported. This study indicates that of the 21 patients 76% were male, with an age range from 15 to 67 years. The lag period for all cancers ranged from 8 months to 60 years. The distribution of the cancer was greatest in the extremities, with 71%, followed by the scalp, with 14%. Forty-three percent of the patients were treated by excision and skin grafting. Twenty-nine percent were treated by amputation, 24% had radiation therapy, and 5% received no treatment. Of the 76% who were followed up to 8 years, no deaths were reported.

Large-area ordered Ni nanowire arrays with different diameters have been fabricated by the direct current electrodeposition into the holes of porous anodic alumina membrane. The crystal structure and micrograph of nanowire arrays are characterized by X-ray diffraction, field-emission scanning electron microscopy and high-resolution transmission electron microscopy. The results indicate that the growth orientation of Ni nanowires turns from [110] to [111] direction with increasing diameters of nanowires. The mechanism of the growth was discussed in terms of interface energy minimum principle. The size-dependent orientation of Ni nanowire arrays has the important significance for the design and control of nanostructures.

The problems encountered during the treatment of a patient with burns covering 40 per cent of the body surface caused by hot chromic acid and the resulting chromium poisoning are described. Anuria developed on the second day after injury and the patient died on the sixth day.

Early vascular grafting has been used to reestablish circulation to the hand in the treatment of electric injuries of the wrist with arterial damage. Since 1972 this therapy has yielded good results by preventing necrosis of the injured hand and by helping to maintain function. However, the indications and timing for performing this operation still are poorly defined. The surgeon is faced with the difficult task of determining whether the injury is severe enough to affect distal circulation and thereby lead to necrosis. The lack of reliable clinical signs is chiefly responsible for this difficulty; however, the potential for delayed thrombosis of vessels complicates the problem. In this article, indications for early vascular grafting in an electrically injured wrist are discussed based on recent clinical experience, with emphasis on the use of arteriography. A case history involving electric burns of both upper extremities is presented as an illustration.

Early vascular grafting is the only effective form of treatment for electrical burns of the wrist which are severe enough to impair blood flow to the hand. Failure to appreciate the significance of early changes in blood flow and to take prompt appropriate action may result in the irreversible loss of blood supply and subsequent amputation. This report analyses the problems encountered in six patients where the early signs of impaired blood flow were not appreciated and amputations were subsequently required.

The use of allomentum to replace automentum or skin flaps in treating 3 patients with severe electrical burns of the wrist is discussed, as are the specific advantages and disadvantages, and the prospects for clinical use of the technique.

From May 1972 to January 1982, early vascular grafting was used to re-establish circulation across the electrically burned wrist. Thirty-three thrombosed arterial segments (radial and/or ulnar arteries) were removed in 18 limbs and autografts of the greater saphenous or omental veins were used for the revascularization. One vascular graft, which had been sutured to the ulnar artery on day 3 post-injury, contained an anastomotic false aneurysm at the proximal anastomosis. One month after vascular grafting, this aneurysm ruptured and bled. An emergency exploration of the wrist confirmed the diagnosis and surgery successfully restored the circulation, avoiding amputation of the injured limb. Histopathological examination of the specimen was consistent with the presence of anastomotic false aneurysm. The pathogenesis of this complication is reviewed. Our experience indicates that circulation to a limb following electrical injury can be successfully restored by early vascular grafting, but emphasizes the importance of close periodical follow-up after graft acceptance due to the possibility of late anastomotic complications.

Deep burns affecting the dorsum of the hand have been treated by tangential excision of the eschar in 156 patients involving 208 hands. From our 10-year experience we have concluded that: 1. 1. If the patient's general condition permits it all hands with deep partial and full thickness skin loss burns are suitable for early tangential excision of the eschar. 2. 2. The best time for the operation is within the first week after injury. 3. 3. If the burn is of limited extent and the requirement for autograft skin is small the operation may be carried out under nerve block anaesthesia. When the burn is more extensive (i.e. involving both hands) intravenous ketamine anaesthesia is recommended. 4. 4. During tangential excision sequential layers of tissue must be removed until the base of the burn appears porcelain white in colour, has a lustrous appearance with many small bleeding points and is firm in consistency. 5. 5. If there are deep burns of the finger webs they are incised or excised and then grafted. 6. 6. Postoperatively an absence of fever, pain or exudation from the wound indicates that inspection of the wound can be delayed for about 2 weeks. By this time the wound is usually healed and functional rehabilitation and physiotherapy can commence.

Since May 1972, vein grafts have been used to restore circulation in electrical injuries of the upper extremity when the wrist has been the centre of electrical injury associated with obstructed blood supply. Saphenous vein grafts were used in fifteen limbs in fourteen patients where electrical injuries at the wrist threatened complete loss of the hand. Ten of the hands were free of necrosis with motion basically recovered. The other four cases (five limbs) failed in operation for various reasons, resulting in forearm amputations. Clinical practice showed that successful operations depend upon whether secondary infection is effectively controlled, particularly in those who were brought to the hospital late with wound infection and gangrene of the fingers. This paper reviews the measures for controlling postoperative infections in vascular grafting to restore blood flow at the wrist, and the clinical experience gained in treating these patients (six injured limbs of six cases), and preventing amputation. We hope the method could be improved and its use broadened.

Silver sulphadiazine has been applied to the burn wounds of 509 patients during the past 10 years. Eleven patients with burns covering more than 20 per cent of the body surface showed silver deposits in the mucosa of the lips, gingiva and cheeks. The colour of the burn wound was also slightly darker than in patients not treated with silver compounds. This darker colour spontaneously disappeared during the year following discharge from hospital. The pathogenesis of silver deposition has been discussed in relation to other published studies.

A study conducted by the University of Colorado Health Sciences Center Burn Center of 42 burned pregnant patients indicates that the mortality of both the fetus and mother is dependent upon the percent body burn of the mother. Aggressive surgical therapy, including debridement with eschar excision and skin grafting, increases maternal survival. Chances of successful pregnancy were greatest when the mother was in her first or third trimester at the time of injury; however, no differences were noted in maternal or fetal mortality at different gestational months.

Twenty-six patients were evaluated with regard to CPK values in week 1 post-burn. Patients were allocated into two groups based on the severity of burn injury. Group 1 included patients with minor electrical or thermal injury, and Group 2 those patients with deep thermal injury and objective evidence of muscle necrosis. With the exception of day 5 post-burn, Group 2 had significantly increased CPK levels as compared to Group 1. This indicates that CPK levels, especially with electrical and deep thermal burns, are sensitive tests in evaluating the depth of burn injury such that an appropriate pre-operative strategy for debriding and grafting is possible.

A patient with high voltage electrical injury affecting the scalp and skull has been treated successfully using autogenous grafts of the greater omentum.

The immunosuppressive effect of burned tissue was studied using a mouse burn model. To evaluate the immunologic status an in vivo measure of cell-mediated immunity (CMI) involving contact sensitization of mice by painting the skin with dinitrofluorobenzene was used; mice were challenged 5 days later by painting the ear with the same antigen. Ear swelling in response to antigenic challenge was used as a quantitative measure of CMI; diminution in ear swelling in treatment mice compared to sensitized, unburned control mice indicated the degree of immunosuppression. A full-thickness steam burn covering 20% body surface ares (BSA) was profoundly immunosuppressive as reflected by ear swelling of 45 to 60% of that found in normal mice; partial thickness burns and burns of 10% BSA extent were not significantly immunosuppressive. Transfer into unburned mice of burned skin equivalent in size to a 20% BSA burn eschar resulted in marked immunosuppression, but transfer of smaller amounts of burned skin, or of larger amounts of unburned skin and normal and burned liver tissue, did not produce immunosuppression. Mice receiving a very high-temperature (300°C), dry burn were only slightly more suppressed than mice receiving a standard steam burn. Normal immunity was preserved in burned mice which received daily application of cerium nitrate to the wound for 7 days, but application of other topical agents commonly used in burn treatment did not preserve immunity. Postburn immunosuppression thus appears related quantitatively to toxic factors in burned skin, and these toxic factors can be abrogated in burned mice by the topical application of cerium nitrate.

The saving of the hand and forearm of a patient with a deep circumferential electrical burn of the wrist and forearm following contact with 10000 V AC demonstrates the important role played by escharotomy and fasciotomy in the early treatment of electrically injured extremities.

Candida infection has become an important cause of morbidity and death in burned or immunosuppressed patients. Two patients with extensive burn complicated with Candida infection are presented, along with the risk factors, diagnostic procedures, and current methods of treatment.

Scalp and skull necrosis often follow high voltage electrical injury to the head. Classically reconstruction of the scalp and skull is performed after sequestration of the necrotic bone. The relatively frequent complication of epidural infection, however, detracts from this approach. As an alternative we have attempted to induce regeneration of devitalized bone by covering it with a vascular tissue flap. A typical patient is described in this report with results which indicate that at least partial regeneration of the necrotic tissue can occur, thus one-stage management of such wounds is possible.

From November 1977 to July 1984, we successfully treated 12 of 14 cases with severe electric burns by free skin flap transfer. A free frontal-exterior femoral flap (one case), free groin flaps (two cases), free scapular flaps (three cases), and free dorsalis pedis flaps (eight cases) were transferre

This report contains our experience gained over 13 years of the tangential excision of burned tissue in 627 patients. We have discussed the indications for and timing of tangential excision, methods of determining the margin between viable and non-viable tissue using histological studies in some patients and the problem of wound coverage after tangential excision.