Revisiting the Electrochemical Nitrogen Reduction on Molybdenum and Iron Carbides: Promising Catalysts or False Positives?

The electrochemical dinitrogen reduction reaction (NRR) has recently gained much interest as it can potentially produce ammonia from renewable intermittent electricity and replace the Haber-Bosch process. Previous literature studies report Fe- and Mo-carbides as promising electrocatalysts for the NRR with activities higher than other metals. However, recent understanding of extraneous ammonia and nitrogen oxide contaminations have challenged previously published results. Here, we critically assess the NRR performance of several Fe- and Mo-carbides reported as promising by implementing a strict experimental protocol to minimize the effect of impurities. The successful synthesis of α-Mo2C decorated carbon nanosheets, α-Mo2C nanoparticles, θ-Fe3C nanoparticles, and χ-Fe5C2 nanoparticles was confirmed by X-ray diffraction, scanning and transmission electron microscopy, and X-ray photoelectron and Mössbauer spectroscopy. After performing NRR chronoamperometric tests with the synthesized materials, the ammonia concentrations varied between 37 and 124 ppb and are in close proximity with the estimated ammonia background level. Notwithstanding the impracticality of these extremely low ammonia yields, the observed ammonia did not originate from the electrochemical nitrogen reduction but from unavoidable extraneous ammonia and NO x impurities. These findings are in contradiction with earlier literature studies and show that these carbide materials are not active for the NRR under the employed conditions. This further emphasizes the importance of a strict protocol in order to distinguish between a promising NRR catalyst and a false positive.

Iron can be microbially extracted from Lunar and Martian regolith simulants and 3D printed into tough structural materials.

In-situ resource utilization (ISRU) is increasingly acknowledged as an essential requirement for the construction of sustainable extra-terrestrial colonies. Even with decreasing launch costs, the ultimate goal of establishing colonies must be the usage of resources found at the destination of interest. Typical approaches towards ISRU are often constrained by the mass and energy requirements of transporting processing machineries, such as rovers and massive reactors, and the vast amount of consumables needed. Application of self-reproducing bacteria for the extraction of resources is a promising approach to reduce these pitfalls. In this work, the bacterium Shewanella oneidensis was used to reduce three different types of Lunar and Martian regolith simulants, allowing for the magnetic extraction of iron-rich materials. The combination of bacterial treatment and magnetic extraction resulted in a 5.8-times higher quantity of iron and 43.6% higher iron concentration compared to solely magnetic extraction. The materials were 3D printed into cylinders and the mechanical properties were tested, resulting in a 400% improvement in compressive strength in the bacterially treated samples. This work demonstrates a proof of concept for the on-demand production of construction and replacement parts in space exploration.

Six years of follow-up after bilateral hand replantation.

Replantation is the gold standard surgical treatment of amputations of the upper limb; however, this demanding procedure is not always preformed in bilateral limb amputation. The objective of this study was to analyze, six years after surgery, the sensorimotor recovery of both replanted hands. A 21-year-old patient with bilateral hand amputation was benefited from limb replantation. Surgery included debridement of the amputated hands and recipient's stumps, bone fixation, arterial and venous anastomoses, nerve sutures, tendon sutures and skin closure. Rehabilitation program included physiotherapy, electrostimulation and occupational therapy. Sensory and motor evaluation was performed 6 years after replantation. At 6 years, the patient presented a good/satisfactory recovery of range of motion and strength, better at right hand. The patient was able to perform right thumb opposition. Static two-point discrimination was 20mm, sensitivity to pain and thermal stimuli and ability to sweat were present on both hands. Reinnervation was confirmed by electromyography. Functional recovery was higher at the right hand when compared to the left hand. He was highly satisfied with the result of surgery for right hand and fairly satisfied with the result for left hand. He was able to return to a secretary work 16 months after the accident. A proper functional result can be accomplished with bilateral hand replantation.

Epithelial-myoepithelial parotid carcinoma after kidney transplantation.

The occurrence of a second malignant neoplasm (SMN) in patients who have been submitted to kidney transplantation is increasing and causes concern; parotid carcinoma is rarely reported after transplantation and may be related to long-term chemotherapy.Salivary gland carcinomas displaying exclusively myoepithelial differentiation-myoepithelial carcinomas (EMC) are rare, being less than 1% of all salivary gland tumours. EMC arises most commonly in the parotid gland and usually occurs in women. Their histopathologic features, immunohistochemical profile and clinical behaviour remain controversial.

Correction of long term joint contractures of the hand by distraction. A case report.

Joint contractures are a common complication of hand trauma. The conventional treatment consists of arthrolysis, tenolysis and occasionally arthrodesis. Frequently, this does not achieve a good result, particularly when there has been a long delay in presentation. Progressive lengthening of a joint by distraction (joint distraction) allows the release of joint contractures even in cases of failure of traditional methods. We present a case of a delayed (20 years) work related traumatic flexion deformity of the PIP joint of the left index and middle fingers. This was the result of a complete division of both flexor tendons of both fingers. The range of movements, both active and passive, was limited to 90/100 degrees in the index finger and 95/100 degrees in the middle finger. Following joint distraction using our lengthening device (Antãotrade mark, Portugal) the patient was able to achieve an active and passive range of movements of 10/100 degrees for the PIP joint of the index finger and 40/100 degrees of the middle. This clinical case shows the simplicity and application of our technique for the correction of joint contractures.

Burn patients in Portugal: analysis of 14,797 cases during 1993-1999.

The incidence and cause of burns in Portugal are unknown. The present study seeks to collect these data as a basis for future studies in prevention and development of treatment regimes. The data used in this work was obtained from the registries existing in The Direcção Geral de Saúde (General Health Administration) and relates to burn patients admitted to 91 Portuguese hospitals--that serve all the territory--during the period of 1993-1999. All patients selected had at least one diagnosis of burn (ICD-9: 94.###) among all the diagnoses motivating an admission. A total of 14,797 burn patients were obtained. Among all the patients admitted to hospitals, 8731 (59.0%) were male and 6066 (41.0%) were female, with a male/female ratio of 1.44:1. The mean length of in-hospital stay was 15.5+/-21.0 days. Throughout this period, 553 (3.7%) patients died in Portuguese hospitals as a result of burn injury. There were no significant differences in the number of deaths in each year, P=0.45, in contrast to the decrease of burn mortality rates reported in other studies. It is likely that the reason for this situation is the lack of investment in the last years in this area and the delay in opening new Burn Centres.

Impaired drainage on diuretic renography using half-time or pelvic excretion efficiency is not a sign of obstruction in children with a prenatal diagnosis of unilateral renal pelvic dilatation.

PURPOSE: Delayed drainage on diuretic renography is an accepted sign of obstruction in adults and symptomatic children. We investigated how to analyze the diuretic challenge as well as assess the significance of impaired drainage. MATERIALS AND METHODS: We followed 24 children with a unilateral prenatal diagnosis of pelvic dilatation up to a minimum of 2 years. A total of 91 diuretic renograms were performed. All children had stable differential renal function and renal pelvic diameter did not change by greater than 9 mm. on sequential ultrasound. Kidneys with stable differential function and no increase in dilatation were considered not obstructed. Analysis of the diuretic challenge included half-time, a post-void image with a change in posture, that is the child erect for 5 to 7 minutes, and drainage considering renal function using the pelvic excretion efficiency. Prolonged drainage was defined as a half-time of greater than 20 minutes or a post-void pelvic excretion efficiency of less than 71%. RESULTS: Median patient age at presentation was 0.32 years and median followup was 3.07 years. The affected nonobstructed hydronephrotic kidney showed impaired drainage in 68% of the children using the half-time parameter, and in 80% and 44% using pelvic excretion efficiency before and after voiding, respectively. Variability in drainage was documented on sequential diuretic renography. CONCLUSIONS: Using the guidelines for data acquisition and processing of diuretic renograms we nevertheless noted impaired drainage in 44% of this young group with nonobstructed kidneys. The half-time parameter was an inappropriate parameter. The diagnosis of obstruction cannot be simply based on delayed drainage in this group of asymptomatic children with a prenatal diagnosis of unilateral renal pelvic dilatation.

The distally based island superficial sural artery flap: clinical experience with 36 flaps.

The principles of neurocutaneous flaps, first described by Masquelet in 1992, represented a new concept in skin vascularization. The distally based superficial sural artery flap is an example of this kind of flap, which is supplied by the vascular axis that accompanies the sural nerve. The authors treated 36 patients with 36 distally based superficial sural artery flaps. All flaps survived, but six of them exhibited partial necrosis. No patient experienced anesthesia of the lateral side of the foot or neuroma at the donor site 12 months after surgery. The authors confirmed that this flap is very useful for soft-tissue reconstruction of the distal third of the leg and foot. Additionally they conclude that the principal advantages are that the blood supply is reliable, execution is easy and fast, the operation can be performed under regional anesthesia, the flap has a large arc of rotation, direct closure of the donor area is possible for small flaps, major arteries or nerves are not sacrificed, and excellent durability is achieved, even on weight-bearing areas. The major drawback is the donor site scar.

Evaluation of carboxymethylcellulose, hydroxypropylmethylcellulose, and aluminum hydroxide as potential carriers for rhBMP-2.

Conventional iliac crest nonvascularized corticocancelous bone grafts and bone flaps have been used to treat bony defects. However, these treatments have some limitations, namely, the availability of donor tissue, donor site morbidity, difficulty to shape the bone flap to the defect, and complexity of the surgery. The bone morphogenetic protein (rhBMP-2) is osteoinductive. However, its implantation requires a matrix (carrier) in order to define the shape of the resulting bone and to retain the protein at the site for the time required for induction to occur. When the ideal carrier is found, an unlimited supply of material would be available for all applications where bone is needed. In this in vitro study, we evaluated the suitability of some potential carriers for rhBMP-2 by measuring the alkaline phosphatase (ALP) activity of fibroblast cultures. Either rhBMP-2 or sodium carboxymethylcellulose significantly increased the ALP activity, when used alone. When sodium carboxymethylcellulose was combined with rhBMP-2, there was an increase in the ALP activity, but lower than those obtained when the products were used alone. Hydroxypropylmethylcellulose alone did not affect ALP activity. However, the combination of rhBMP-2 with hydroxypropylmethylcellulose did not increase the ALP activity, despite the presence of rhBMP-2. Aluminium hydroxide proved to be an unsuitable rhBMP-2 adsorbent.

[Microsurgical reconstruction of the upper extremity. Experience with 24 free flaps]. / Reconstrução microcirúrgica do membro superior. Experiência de 24 retalhos livres.

The authors present the experience of 24 clinical cases of microsurgical reconstruction of the upper limb. These reconstructions were accomplished by different microvascular free flaps which were selected according to the type, size and location of the defects, having applied fasciocutaneous, adipofascial, myo, myocutaneous, tendofasciocutaneous, omentum flaps and 2nd toe transfers. The etiology was traumatic in 23 cases and tumoral in 1 case. A careful analysis was made for surgical times, selection and survival rate of the free flaps and the morphofunctional quality of the reconstructions. Microvascular free flaps are considered the choice technique for upper limb reconstruction, particularly for the hand in certain defects, considering the better anatomic and functional quality of the reconstructions.

[Revascularization and reimplantation of the upper extremity. 15-year-experience with 114 cases]. / Revascularizações e reimplantações do membro superior. 15 Anos de experiência com 114 casos.

Progress in micro or macro replantation has resulted in higher survival rates of formerly amputated parts. More amputated digits or limbs survive because the time of ischemia can be exceeded by using cold storage or perfusion. Homo or heterodigital vessel transposition, expanded indications for vein graft interposition, as well as heterotopic transplantation allow for extremity preservation even in crush injuries, and in disastrous multiple amputations combined with contusion or avulsion. Secondary reconstruction with regard to bone defects, tendon repair, and eventual nerve grafting have to be aspired, finally leading to an improvement of functional results in daily and leisure activities as well as in early professional readaptation. A total of 114 microvascular extremity replantations/revascularizations with a survival rate of 77.2% were followed for an average of 15 years.

[Free flaps in the reconstruction of head and neck. Clinical experience]. / Retaehos livres na reconstrução da cabeça e pescoço. Experiência clínica.

The reconstruction of head and neck defects, due to trauma, tumor resection or other, begins with a careful assessment of the patient and the respective defect. Ideally, it ends with the successful reconstructive procedure that optimally restores form and function to the patient. Free flaps have often been used as a last resort reconstructive option in the head and neck because of the need for added technical skill, a longer operating time and a perception of poor reliability. This study reviews our experience with forty-eight patients submitted to microvascular reconstructive procedures. Twelve different kinds of free flaps have been involved as the preferred choice for free flap reconstruction of a specific defect of the head and neck. The latissimus dorsi flap was used for scalp and skull reconstruction, whereas the serratus anterior or rectus abdominis free flaps were used for the reconstruction of complex defects of the middle third of the face. The radial forearm flap and the free jejunal transfer have become the preferred choices for intraoral and pharyngo-esophageal reconstruction, respectively. Good results were obtained with both functional and social rehabilitation. There were three flap losses probably due to thrombosis of the microvascular anastomosis. There was no surgical mortality. The indications for each free flap are discussed.

[Cutaneous reconstruction at the leg and foot level. Experience in 277 clinical cases]. / Reconstrução cutânea ao nivel da perna e do pe. Experiência em 227 casos clínicos.

The authors present their clinical experience of leg and foot reconstruction with 227 clinical cases. Based on these cases the authors analyse the use of 18 musculocutaneous, 53 axial, 72 septocutaneous and 84 free flaps, totalling 29 different kinds of flaps performed. Although no definitive conclusions can be drawn about which are the best flaps for foot and leg reconstruction, the preferential options are pointed out.

Reverse dorsal metacarpal osteocutaneous flap.

There are a number of possibilities for local and vascularized bone transfer when a small amount of cortico-cancellous bone is required in the hand and fingers. The authors describe the dissection technique and a clinical application of a reverse dorsal metacarpal osteocutaneous flap to reconstruct the proximal phalanx of a fifth finger. They emphasise the bone vascularisation, studied 48 hours postoperatively with a bone scan and confirmed with bone healing 4 weeks later. The advantages are: it is a compound flap, easy to dissect under tourniquet in one operation, it can be done in an emergency care situation and it does not require ligation of an important vascular axis. The essential precaution is to visualise the patency of the fourth dorsal metacarpal artery before flap dissection, acknowledging that in only 63% of cases is there a vascular pattern that allows flap dissection with a long arc of rotation.

A new approach in axillary hidradenitis treatment: the scapular island flap.

The scapular island flap technique has been used in the treatment of seven cases of axillary hidradenitis suppurativa. This flap, providing a smooth skin surface with good elastic properties, easily covers the axilla and permits the cutaneous reconstruction of the involved axillary tissue excision with satisfying aesthetic, functional results and a rapid local cicatrization. The donor site was closed by primary suture.

[Utilization of forearm island flaps in reconstructive surgery of the hand. Which one is the best option?]. / A utilização de retalhos antebraquiais em ilha na cirurgia reconstrutiva da mão. Qual a melhor opção?

The authors report their clinical experience after seventy-six forearm island flaps, and analyse the different possible forearm flap options in hand reconstructions. The different flaps-based on the radial, ulnar, interosseous and septocutaneous ulnar vessels-are compared in what, concerns the importance of the sacrificed artery, adverse sequelae of the donor area and their versatility to close large skin defects as well as their capacity to reach distal areas of the hand. Their ability to provide sensate coverage and to replace bone and tendons is also compared.

Halux pulp composite graft in nipple reconstruction.

We present a nipple reconstruction method that uses a composite graft of a constant halux's prominence. This technique, which has advantages over nipple reconstruction with toe pulp free grafts, has produced good results.

[The treatment of burn patients. What are the prospects for the northern area of Portugal?]. / Tratamento de queimados. Que perspectivas para a zona norte de Portugal?

The AA studied the distribution of age, sex, aetiology, and destiny of the 173 in-patients at the S. João Hospital (Central hospital that has no Burn Unit). In what concerns age, 38.1% are children less than 10 years old; the male/female ratio was 1.7:1. The fire and scalds are the most important aetiology. These findings are similar to those found in other countries (except in the Arabian Countries). Of these 99 burn patients have been treated in S. João Hospital, 71 patients were sent to the Burn Unit of Prelada Hospital and 3 to the Burn Unit of Coimbra University Hospital. These findings were compared to a Burn Unit of a Spanish Hospital (Alicante) which has 18 beds for adults and children, normally interning 132 patients per year. As the WHO suggest one special bed per 30,000 persons, we should be expected to have at least 110 beds for burn patients (we only have 9 beds at Prelada Hospital), the AA suggest the establishment of a Burn Unit at S. João Hospital, also due to the fact that is the only hospital that has a permanent emergency care for Plastic Surgery.

The galea frontalis myofascial flap in anterior fossa CSF leaks.

We report the clinical use of galea frontalis myofascial flaps in the treatment of anterior fossa cerebrospinal fluid leaks after trauma. This flap provides an adequately sized and vascularised barrier between the cranial and nasal cavities through which the cells of the inflammatory response reach the target area. This technique was used in 9 cases with complete success; in 5 out of 9 patients, repair of an anterior cranial base bone defect was also performed with split calvarial bone grafts, harvested from the frontal craniotomy bone. In all patients, neither recurrence of the CSF leakage nor postoperative meningitis or its recurrence were observed.