Tunable Gas Admission via a "Molecular Trapdoor" Mechanism in a Flexible Cationic Metal-Organic Framework Featuring 1D Channels.

Achieving high gas selectivity is challenging when dealing with gas pairs of similar size and physiochemical properties. The "molecular trapdoor" mechanism discovered in zeolites holds promise for highly selective gas adsorption separation but faces limitations like constrained pore volume and slow adsorption kinetics. To address these challenges, for the first time, a flexible metal-organic framework (MOF) featuring 1D channels and functioning as a "molecular trapdoor" material is intoduced. Extra-framework anions act as "gate-keeping" groups at the narrowest points of channels, permitting gas admissions via gate opening induced by thermal/pressure stimuli and guest interactions. Different guest molecules induce varied energy barriers for anion movement, enabling gas separation based on distinct threshold temperatures for gas admission. The flexible framework of Pytpy MOFs, featuring swelling structure with rotatable pyridine rings, facilitates faster gas adsorption than zeolite. Analyzing anion properties of Pytpy MOFs reveals a guiding principle for selecting anions to tailor threshold gas admission. This study not only overcomes the kinetic limitations related to gas admission in the "molecular trapdoor" zeolites but also underscores the potential of developing MOFs as molecular trapdoor adsorbents, providing valuable insights for designing ionic MOFs tailored to diverse gas separation applications.

The phylogenetic structure and coalescent species delimitation of an endemic trapdoor spider genus, Stasimopus (Araneae, Mygalomorphae, Stasimopidae) in the Karoo region of South Africa.

The Karoo region of South Africa is a unique and sensitive ecosystem which is facing pressure for development due to economic incentives such as mining, farming and shale gas exploration. The species diversity of many taxa in the area is largely unknown. A phylogenetic analysis of the cork-lid trapdoor spider genus, Stasimopus (Stasimopidae) was undertaken in order to gain insight into the relationships between the species that may be present in the area. The species within Stasimopus are challenging to identify and define using traditional morphological methods due to a high degree of morphological conservatism within the genus. For this reason, multiple coalescent based species delimitation methods were used to attempt to determine the species present for Stasimopus in the region which was tested against the morphological identifications and genetic clades (based on CO1, 16S and EF-1É£). We tested single-locus methods Automatic Barcode Gap Discovery (ABGD), Bayesian implementation of Poisson Tree Processes (bPTP) and General Mixed Yule- Coalescent (GMYC), as well as multi-locus Brownie. The phylogenetic analysis of Stasimopus in the Karoo showed that there is a high degree of genetic diversity within the genus. The species delimitation results proved unfruitful for the genus, as they appear to delimit population structure rather than species for most methods. Alternative methods should be investigated to aid in the identification of the species in order truly understand the species diversity of the genus.

Passive Soil Arching Effect in Aeolian Sand Backfills for Grillage Foundation.

The passive soil arching effect exists in many soil-grille interaction systems. Increasing mental grillage foundations are used for transmission lines in aeolian sand areas; thus, exploring the evolution mechanism of passive soil arching is crucial. This study investigates the evolution and influencing factors of passive soil arching through a series of tests using a trapdoor device and particle image velocimetry (PIV). The test results show that the evolution of the arching structure causes the aeolian sand deformation to gradually extend to the backfill surface and stationary zone, generating two triangular arching surfaces between the movable beams and sliding surface at the junction of the active and stationary zones. Cracks in the arching and sliding surfaces were connected to form a W-shaped shear band. The development of the soil pressure was divided into four arching structure stages. The different stages of the inner and outer arches of the bearing characteristics had strong differences. Taking the appearance of the first arch surface as the time point, the soil pressure changes abruptly and the inner and outer arches alternate to bear the as a major role. The beam spacing significantly affected the arching evolution. A smaller beam spacing formed an initial bending configuration with an inconspicuous arching structure and incomplete shear band. As the beam spacing increased, the arching shape changed from triangular to parabolic, sudden changes in the soil pressure were more pronounced, and the arch height increased. The relative density and water content had little impact on the arch shape and shear zone but significantly affected the arching strength, soil pressure transfer, and arching height. The medium and high relative densities and low water contents resulted in a stronger arching structure and greater arching height, while low relative densities and high water contents weakened the soil pressure transfer. The range values for the optimum beam spacing, relative density, and water contents are given based on the variation characteristics of the evaluated parameters (E, n) under different conditions.

Efficient Equality Test on Identity-Based Ciphertexts Supporting Flexible Authorization.

In the cloud, uploading encrypted data is the most effective way to ensure that the data are not leaked. However, data access control is still an open problem in cloud storage systems. To provide an authorization mechanism to limit the comparison of a user's ciphertexts with those of another, public key encryption supporting the equality test with four flexible authorizations (PKEET-FA) is presented. Subsequently, more functional identity-based encryption supporting the equality test (IBEET-FA) further combines identity-based encryption with flexible authorization. The bilinear pairing has always been intended to be replaced due to the high computational cost. Hence, in this paper, we use general trapdoor discrete log groups to construct a new and secure IBEET-FA scheme, which is more efficient. The computational cost for the encryption algorithm in our scheme was reduced to 43% of that of the scheme of Li et al. In Type 2 and 3 authorization algorithms, the computational cost of both was reduced to 40% of that of the scheme of Li et al. Furthermore, we give proof that our scheme is secure against one-wayness under the chosen identity and chosen ciphertext attacks (OW-ID-CCA), and indistinguishable against chosen identity and chosen ciphertext attacks (IND-ID-CCA).

Surgical hip dislocation for treatment of femoral head chondroblastoma: efficacy and safety.

PURPOSE: Femoral head chondroblastoma poses a surgical challenge. Anatomical limitations may lead to increased risk of local recurrence, damage to the articular cartilage, growth disturbances, and/or avascular necrosis (AVN). We are presenting our results with surgical hip dislocation approach with the aim to evaluate its efficacy in preventing recurrence and its safety, preserving a functional hip joint and avoiding complications. PATIENTS AND METHODS: Ten patients were managed using surgical hip dislocation with direct access to femoral head lesions, extended curettage through a modified trapdoor approach, and cement reconstruction. These were six males and four females, with a mean age of 17 ± 2.7 years (range: 14-20) and a mean follow-up of 34 ± 12 months (range: 17-57). The lesion extended into the neck in 60% of patients with the physis being either closed in seven or closing in three patients. RESULTS: We had a single case (10%) of recurrence at the trochanters for which re-curettage was done. However, all patients had their hips preserved with good function at the latest follow-up, and no serious complications recorded. The Musculoskeletal Tumor Society score improved significantly from a pre-operative median of 23.5 (range: 16-28) to a post-operative median of 29 (range: 26-30) (P = 0.005). CONCLUSION: This report describes a safe reproducible approach to effectively manage these locally aggressive lesions with good short-term results. This is done while maintaining the integrity of the articular surface, growth plate, as well as preserving the femoral head blood supply.

Entrapment of the inferior oblique and inferior rectus muscles in orbital trapdoor fracture.

A 10-year-old male presented to our institution 6 days after sustaining trauma to his right eye from a fall. A thorough physical examination could not be done due to severe eye pain and inability to open the eyelids; however, computed tomographic imaging done at this time showed a trapdoor fracture with incarceration of the inferior oblique and inferior rectus muscles. The fracture was reduced through a transconjunctival incision and secured with a polytetrafluoroethylene implant. Three months after the surgery, extraocular motility is almost full and equal.

Treating complex palmar-plantar wounds using a bilaminar 'trapdoor' technique: a case series.

OBJECTIVE: Due to the similarities of glabrous skin, the plantar region is an excellent donor area for covering complex palmar-plantar wounds. However, taking grafts from the plantar area often results in significant morbidity at the donor site or non-integration of the graft due to the greater thickness of the plantar corneal layer. METHOD: This is a prospective case series including patients with burns or wounds who have been treated with a dermal graft using the bilaminar 'trapdoor' technique. This procedure is used to remove a thin graft from the deep plantar dermis after the partial elevation of the first layer including the entire epidermis and superficial part of the dermis. RESULTS: At the donor area in the four patients in this case series, we observed healing at around 10 days, and absence of hypertrophic scar in all patients. There was complete re-epithelialisation between two and three weeks from the periphery to the centre of the deep dermal graft, and from the glandular epithelium transferred with the graft. During the follow-up, patients presented aesthetic and functional features of glabrous and amelanotic skin, with similar resistance to those of the adjacent areas of the wound in the palmar-plantar region. CONCLUSION: This technique has some advantages, such as less surgical time, minimal morbidity in the plantar donor area, easy integration of the grafts, and maintenance of the functional and aesthetic properties of glabrous skin both in the plantar donor area and in the palmar-plantar recipient region. DECLARATION OF INTEREST: The authors have no conflicts of interest to declare.

A Lattice-Based Homomorphic Proxy Re-Encryption Scheme with Strong Anti-Collusion for Cloud Computing.

The homomorphic proxy re-encryption scheme combines the characteristics of a homomorphic encryption scheme and proxy re-encryption scheme. The proxy can not only convert a ciphertext of the delegator into a ciphertext of the delegatee, but also can homomorphically calculate the original ciphertext and re-encryption ciphertext belonging to the same user, so it is especially suitable for cloud computing. Yin et al. put forward the concept of a strong collusion attack on a proxy re-encryption scheme, and carried out a strong collusion attack on the scheme through an example. The existing homomorphic proxy re-encryption schemes use key switching algorithms to generate re-encryption keys, so it can not resist strong collusion attack. In this paper, we construct the first lattice-based homomorphic proxy re-encryption scheme with strong anti-collusion (HPRE-SAC). Firstly, algorithm TrapGen is used to generate an encryption key and trapdoor, then trapdoor sampling is used to generate a decryption key and re-encryption key, respectively. Finally, in order to ensure the homomorphism of ciphertext, a key switching algorithm is only used to generate the evaluation key. Compared with the existing homomorphic proxy re-encryption schemes, our HPRE-SAC scheme not only can resist strong collusion attacks, but also has smaller parameters.

Anatomical implication of less occurrence of inferior oblique muscle entrapment in orbital floor trapdoor fracture.

PURPOSE: To examine the anatomy of the inferior oblique (IO) muscle and its surrounding structures to clarify why IO muscle entrapment develops less in orbital floor trapdoor fractures. METHODS: Computed tomographic (CT) images on the unaffected sides were obtained from 64 patients with unilateral orbital fractures. On coronal planes, presence or absence of an infraorbital groove below the IO muscle was confirmed. At the level of the medial margin of the infraorbital groove/canal, the distance from the orbital floor to the IO muscle (IO-floor distance), the thickness of the orbital floor, and the shortest distance from the inferior rectus (IR) muscle to the orbital floor (shortest IR-floor distance) were measured. On quasi-sagittal planes, the distances from the inferior orbital rim to the inferior margin of the IO muscle (IO-rim distance) and the most anterior point of the infraorbital groove (groove-rim distance) were measured. RESULTS: The infraorbital groove was found below the IO muscle in eight patients (12.5%), and the IO-rim and IO-floor distances were significantly longer than the groove-rim and shortest IR-floor distances, respectively (p < 0.001). The orbital floor below the IO muscle was significantly thicker than that below the IR muscle (p < 0.001). CONCLUSION: Although the medial margin of the infraorbital groove is the most common fracture site, the IO muscle was not located above the groove in most cases. A longer IO-floor distance and thicker orbital floor below the IO muscle may also contribute to less occurrence of IO muscle entrapment in orbital floor trapdoor fractures.

Shifting evolutionary sands: transcriptome characterization of the Aptostichus atomarius species complex.

BACKGROUND: Mygalomorph spiders represent a diverse, yet understudied lineage for which genomic level data has only recently become accessible through high-throughput genomic and transcriptomic sequencing methods. The Aptostichus atomarius species complex (family Euctenizidae) includes two coastal dune endemic members, each with inland sister species - affording exploration of dune adaptation associated patterns at the transcriptomic level. We apply an RNAseq approach to examine gene family conservation across the species complex and test for patterns of positive selection along branches leading to dune endemic species. RESULTS: An average of ~ 44,000 contigs were assembled for eight spiders representing dune (n = 2), inland (n = 4), and atomarius species complex outgroup taxa (n = 2). Transcriptomes were estimated to be 64% complete on average with 77 spider reference orthologs missing from all taxa. Over 18,000 orthologous gene clusters were identified within the atomarius complex members, > 5000 were detected in all species, and ~ 4700 were shared between species complex members and outgroup Aptostichus species. Gene family analysis with the FUSTr pipeline identified 47 gene families appearing to be under selection in the atomarius ingroup; four of the five top clusters include sequences strongly resembling other arthropod venom peptides. The COATS pipeline identified six gene clusters under positive selection on branches leading to dune species, three of which reflected the preferred species tree. Genes under selection were identified as Cytochrome P450 2c15 (also recovered in the FUSTr analysis), Niemann 2 Pick C1-like, and Kainate 2 isoform X1. CONCLUSIONS: We have generated eight draft transcriptomes for a closely related and ecologically diverse group of trapdoor spiders, identifying venom gene families potentially under selection across the Aptostichus atomarius complex and chemosensory-associated gene families under selection in dune endemic lineages.

Trapdoor anterior thoracotomy for cervicothoracic and apical thoracic neuroblastoma in children.

PURPOSE: Cervicothoracic and apical thoracic neuroblastoma pose unique surgical challenges. We report our experience with the trapdoor anterior thoracotomy (TAT) approach to overcome these difficulties. METHODS: Retrospective review of our centre's neuroblastoma database was conducted. Patients who underwent TAT at our centre were included, their demographic data and clinical reports were analyzed. RESULTS: A total of 21 patients underwent TAT for neuroblastoma, mean age at surgery of 3.5 (0.3-7.9) years, male to female ratio was 11:10. Fifteen patients had cervicothoracic tumors while 6 had apical thoracic tumors. All except 2 were primary tumors. They were stage M (n = 12), MS (n = 1), and L2 (n = 8). At pre-operative assessment, 19 patients had image-defined risk factor (IDRF), including dual compartmental involvement (n = 15), trachea/bronchus compression (n = 4), encasement of carotid (n = 5), subclavian (n = 11), and vertebral arteries (n = 6). Four underwent upfront surgery while 17 received pre-operative chemotherapy of 2-8 (mean 3.9) cycles. All patients accomplished gross total resection. None had MYCN amplification. The postoperative complications included Horner's syndrome (n = 21), Klumpke's palsy (n = 1), winged scapula (n = 1), phrenic nerve palsy (n = 1), and bronchomalacia (n = 2). CONCLUSION: Gross total resection of cervicothoracic and apical thoracic neuroblastoma can be accomplished by TAT with minimal morbidity.

An Efficient Certificateless Aggregate Signature Scheme for Blockchain-Based Medical Cyber Physical Systems.

Different from the traditional healthcare field, Medical Cyber Physical Systems (MCPS) rely more on wireless wearable devices and medical applications to provide better medical services. The secure storage and sharing of medical data are facing great challenges. Blockchain technology with decentralization, security, credibility and tamper-proof is an effective way to solve this problem. However, capacity limitation is one of the main reasons affecting the improvement of blockchain performance. Certificateless aggregation signature schemes can greatly tackle the difficulty of blockchain expansion. In this paper, we describe a two-layer system model in which medical records are stored off-blockchain and shared on-blockchain. Furthermore, a multi-trapdoor hash function is proposed. Based on the proposed multi-trapdoor hash function, we present a certificateless aggregate signature scheme for blockchain-based MCPS. The purpose is to realize the authentication of related medical staffs, medical equipment, and medical apps, ensure the integrity of medical records, and support the secure storage and sharing of medical information. The proposed scheme is highly computationally efficient because it does not use bilinear maps and exponential operations. Many certificateless aggregate signature schemes without bilinear maps in Internet of things (IoT) have been proposed in recent years, but they are not applied to the medical field, and they do not consider the security requirements of medical data. The proposed scheme in this paper has high computing and storage efficiency, while meeting the security requirements in MCPS.

The Lister's tubercle trapdoor: a minimally invasive technique for harvesting cancellous bone from the distal radius.

Bone graft harvest from the distal radius, immediately proximal to the Lister's tubercle, is a common technique in upper limb surgery. Here, we present a minimally invasive technique to harvest bone graft using a replaceable, well vascularized access trapdoor. The hinged trapdoor technique allows a small incision over Lister's tubercle and does not violate the fibro-osseous tunnel of the third compartment. Nearby structures like the superficial radial nerve, extensor carpi radialis brevis and extensor pollicis longus are safely protected throughout. Closure of the trapdoor creates a smooth surface and therefore little or no surrounding trauma.

Searchable Encryption Scheme for Personalized Privacy in IoT-Based Big Data.

The Internet of things (IoT) has become a significant part of our daily life. Composed of millions of intelligent devices, IoT can interconnect people with the physical world. With the development of IoT technology, the amount of data generated by sensors or devices is increasing dramatically. IoT-based big data has become a very active research area. One of the key issues in IoT-based big data is ensuring the utility of data while preserving privacy. In this paper, we deal with the protection of big data privacy in the data storage phase and propose a searchable encryption scheme satisfying personalized privacy needs. Our proposed scheme works for all file types including text, audio, image, video, etc., and meets different privacy needs of different individuals at the expense of high storage cost. We also show that our proposed scheme satisfies index indistinguishability and trapdoor indistinguishability.

An Aggregate Signature Scheme Based on a Trapdoor Hash Function for the Internet of Things.

With the rapid development of the Internet of Things (IoT), it becomes challenging to ensure its security. Identity authentication and integrity verification can be achieved by secure hash functions and digital signature algorithms for IoT applications. In order to solve the issues of bandwidth limitation and computational efficiency of secure communication in IoT applications, an aggregate signature scheme based on multi- trapdoor hash function is proposed in this paper. Firstly, to prevent key exposition, based on the elliptic curve discrete logarithm problem (ECDLP), we constructed a double trapdoor hash function (DTH) and proved its reliability. Secondly, the multi-trapdoor hash function (MTH) based on DTH is presented. Finally, an MTH-based aggregate signature scheme (MTH-AS) with constant signature length is proposed. Based on the assumption of ECDLP, the proposed scheme is proven unforgeable against adaptive chosen message attacks with the Forking Lemma. Different from the most signature schemes with bilinear mapping, the proposed scheme has higher computational efficiency and shorter aggregate signature length. Moreover, it is independent of the number of signers. Security analysis and performance evaluation has revealed that the proposed scheme is an ideal solution for secure IoT applications with limited computing power, storage capacity, or limited bandwidth, such as wireless sensor networks, vehicular ad hoc networks, or healthcare sensor networks.

Incarceration of the inferior oblique muscle branch of the oculomotor nerve in patients with orbital floor trapdoor fracture.

PURPOSE: To examine the clinical characteristics of patients with concomitant incarceration of the inferior oblique muscle branch of the oculomotor nerve who had suffered from an orbital floor trapdoor fracture with orbital fat incarceration. METHODS: Fifty-nine patients were retrospectively reviewed. Concomitant inferior oblique muscle branch incarceration was diagnosed by inferior oblique muscle underaction on the Hess chart and a missing inferior oblique muscle branch on computed tomographic images on baseline examination. RESULTS: Eleven patients (18.6%) were diagnosed with concomitant branch incarceration. The patients with branch incarceration were all under 19 years of age, and were younger than those without branch incarceration (P = 0.026). There were no significant differences between the groups in terms of cause of injury, presence of concomitant medial wall fracture, hypoesthesia of the cheek region, or ocular and periocular complications (P > 0.050). All patients with branch incarceration underwent surgical reduction, whereas 16 of 48 patients without branch incarceration were observed without surgery (P = 0.021). Although preoperative binocular single vision field was smaller in patients with branch incarceration (P = 0.026), it improved after surgery, comparable to that of patients without branch incarceration (P = 0.079). CONCLUSIONS: Concomitant incarceration of inferior oblique muscle branch of the oculomotor nerve occurred in 18.6% of patients who had suffered from an orbital floor trapdoor fracture with orbital fat incarceration. Patients with branch incarceration were all under 19 years of age. Branch incarceration resulted in a smaller binocular single vision field, which considerably improved after surgical reduction.

A new concept for tuberosity repair in hemiarthroplasty for fracture: use of a clamp and underlying ledge to form a trapdoor.

BACKGROUND: Sutures are the most common method for tuberosity repair in hemiarthroplasty for fracture. Despite numerous suggested patterns, tuberosity repair remains a weak point leading to poor functional results. This study mechanically tested a new mechanism that avoids difficulties sutures may engender. The hallmark of the prosthesis is a "trapdoor" effect. Low-profile metallic clamps with undersurface stoppers are screwed across the tuberosity-tendon junction to an underlying ledge, creating a fixed metallic space. With cuff contraction, the tuberosities are too large to pull through this space. MATERIALS AND METHODS: Tests were carried out in line with the U.K. Human Tissue Authority regulations. Four-part fractures in 8 cadavers repaired with this method were subjected to simultaneous cyclic tension of 350N and passive glenohumeral motion for 8000 cycles. Both before and after machine stress, repairs were assessed by clasping each tuberosity with a forceps and attempting to displace it in a variety of directions. No movement was present before stressing. Any post-stress movement was considered a failure and recorded in millimeters. RESULTS: Six specimens after machine stress showed 0-mm movement (95% confidence interval, 34.9%-96.8%). Isolated movements of a single tuberosity occurred in 2 specimens. CONCLUSION AND DISCUSSION: The trapdoor completely withstood challenging elements of cyclic load and passive motion in 75% of cases. The device may represent an alternative to sutures.

The oculocardiac reflex in an adult with a non-displaced orbital floor fracture.

The current dogma is that the oculocardiac reflex from orbital trapdoor fractures occurs only in children and young adults. We present the occurrence of the oculocardiac reflex in an adult with a non-displaced orbital floor fracture. CT demonstrated the adventitia surrounding the inferior rectus trapped in and below the orbital floor fracture. The patient's oculocardiac reflex resolved by early next morning, presumably from the tissue escaping from the orbital floor defect.

Management of pure orbital floor fractures: a proposed protocol to prevent unnecessary or early surgery.

PURPOSE: To present a case series review of management of pure orbital floor fractures and propose a protocol. METHODS: A retrospective review of medical records and computed tomography (CT) scan findings was completed. Fractures were classified into either trap-door, floor-fracture with incarcerated tissue, or depressed floor-fragment fractures. Criteria for surgical success were: enophthalmos <1mm; no hypoglobus/hyperglobus; extra-ocular muscle restriction <5° in upgaze but normal in all other positions on Hess chart; and no diplopia other than in extreme upgaze (5°). RESULTS: A total of 79 patients with orbital floor fractures were identified. There were 6 trap-door type fractures, 42 floor fractures with incarcerated tissue, and 31 depressed floor-fragment type fractures. Thirty-six patients were managed conservatively (antibiotics and observation). In nine of these, surgery was avoided by adhering to our protocol of delayed repair. Forty-three had surgical intervention: 6 were trap-door-type, 18 had a floor fracture with incarcerated tissue and 19 were of the depressed floor-fragment variety. All trap-door fractures underwent early repair (6/43, 14%), the rest had delayed repair (37/43, 84%). Four of 6 trap-door fractures had a successful outcome (66.6%). All 18 fractures with incarcerated tissue underwent successful delayed repair. Seventeen of 19 patients with depressed floor-fragment fractures were treated successfully surgically. The follow-up ranged from 12-64 months. The overall success rate was 85.3%. CONCLUSION: Non-trap-door type of floor fractures can have a successful outcome with delayed repair. This can avoid unnecessary surgery in selected cases. A management protocol is proposed.

[Early hypertrophic scar after surgery on the nasal region: value of long-acting corticosteroid injections]. / Hypertrophie cicatricielle précoce post-chirurgicale de la région nasale : intérêt des injections de corticoïde retard.

BACKGROUND: "Pincushioning" is a complication of post-surgical scarring following use of transposition flaps particularly when surgery is performed on the nasal region. The transposition flap technique is very useful for the repair of certain defects of the tip of the nose, the medial canthus or of the ala nasi. The aim of this study is to define the clinical characteristics of this scarring dystrophy, which we propose to call "early hypertrophy scarring", to clarify the nature thereof and to assess the efficacy of intralesional injection of corticosteroids at the first signs of hypertrophy. PATIENTS AND METHOD: A prospective, open, non-comparative, single-centre study examined the clinical and histological characteristics of early hypertrophy scarring and the effectiveness of therapy with one or two injections of corticosteroids performed on the 15th day post-operatively and optionally repeated at D45 depending on the outcome. From January 2011 to January 2013, 12 consecutive patients with early hypertrophy scarring were included (ten men and two women - mean age: 64 years). All had undergone surgery for basal cell carcinoma under local anaesthesia with one-stage repair by means of a rhombic flap or a bilobed flap located in the nasal area. Scars were injected strictly intra-lesionally with triamcinolone acetate (40 mg/1 mL) until whitening occurred. A single injection was performed in three cases of rhombic flap while a second injection was given at D45 in the remaining nine cases. RESULTS: Complete regression of the early hypertrophy scarring was obtained in ten of the 12 patients by D90. Incomplete regression was observed but with a marked improvement in the other two patients. DISCUSSION: Early hypertrophy scarring is distinguished by its clinical characteristics of hypertrophic or keloid scars. Biopsy performed in two cases showed the fibrous but non-fatty nature of early hypertrophy scarring. Biomechanical factors particular to the nasal region and the transposition flap technique could account for the early and excessive collagen production causing early hypertrophy scarring. Early injection of corticosteroids, which was consistently effective in our study, could represent a simple treatment for early hypertrophy scarring, thus avoiding surgical correction. These preliminary results in a small number of patients require confirmation by a comparative, multicentre, prospective controlled study.