Boosting the thermal management performance of a PCM-based module using novel metallic pin fin geometries: Numerical study.

Satellite avionics and electronic components are getting compact and have high power density. Thermal management systems are essential for their optimal operational performance and survival. Thermal management systems keep the electronic components within a safe temperature range. Phase change materials (PCMs) have high thermal capacity, so they are promising for thermal control applications. This work adopted a PCM-integrated thermal control device (TCD) to manage the small satellite subsystems under zero gravity conditions thermally. The TCD's outer dimensions were selected upon a typical small satellite subsystem. The PCM adopted was the organic PCM of RT 35. Pin fins with different geometries were adopted to boost the lower thermal conductivity of the PCM. Six-pin fins geometries were used. First, the conventional geometries were square, circular, and triangular. Second, the novel geometries were cross-shaped, I-shaped, and V-shaped fins. The fins were designed at two-volume fractions of 20% and 50%. The electronic subsystem was assumed to be "ON" for 10 min releasing 20 W of heat, and "OFF" for 80 min. The findings show a remarkable decrease in the TCD's base plate temperature by 5.7 ℃ as the fins' number changed from 15 to 80 for square fins. The results also show that the novel cross-shaped, I-shaped, and V-shaped pin fins could significantly enhance thermal performance. The cross-shaped, I-shaped, and V-shaped reported a decrease in the temperature by about 1.6%, 2.6%, and 6.6%, respectively, relative to the circular fin geometry. V-shaped fins could also increase the PCM melt fraction by 32.3%.

Natural radioactivity levels in some vegetable crops under greenhouse conditions.

Estimating any radioactivity released into the environment is critical for public health protection, particularly if the radioactivity can enter the food chain. In the present work, the activity concentration of natural radionuclides in the soil, water, plants, and fruits of four vegetable crops, namely cucumber, sweet pepper, hot pepper, and tomato, growing under greenhouse conditions has been measured using a High Purity Germanium (HPGe) Detector. The measured activity concentrations for 226Ra, 232Th, and 40K in the studied soil samples ranged from 4.7 to 6.8, 3.4 to 6.1, and 63.9 to 112.4 Bq kg-1, respectively, while in plants, they ranged from Not Detected (ND) to 15.2, ND to 3.4, and 495.1 to 1467.4 Bq kg-1, respectively. The measured activity concentrations for 40K in the studied fruit samples ranged from 967.1 to 1459.1 Bq kg-1, while 226Ra and 232Th were not detected. The Transfer Factor (TF) of 226Ra, 232Th, and 40K from soil to plants and fruits has been evaluated, and the results from soil to plants varied from ND to 2.5, ND to 0.8, and 6.0 to 19.2, while the results for 40K in fruits varied from 8.7 to 18.4, while 226Ra and 232Th were not detected.

Effect of chromium contents on radiation shielding and macroscopic cross-section in steel alloys.

By using an electro-slag re-melting procedure, new shielding steel alloys with varying chromium concentrations ranging from 2 to 18%, and a reduced nickel content of roughly 12% were developed. The mass attenuation µm, mean free path (MFP), effective atomic number Zeff, and electron density Neff, the energy buildup factor (EBF), and the energy absorption buildup factor (EABF) were calculated for the new developed steel alloys by using Phy-X/PSD software over the photon energy range (0,015-15 MeV). Furthermore, using the NGCAL online software, the macroscopic effective neutron removal cross-sections (ΣR) for 25.4 meV thermal neutrons, 4 MeV fast neutrons, and 10 MeV fast neutrons were determined. All cobalt-free steel prepared samples (S1, S2, S3, S4, and S5) were found to have lower mean free path (MFP) and half-value layer (HVL) values, as well as greater macroscopic effective neutrons removal cross section (ΣR) values, than their estimated equivalents for both carbon steel and stainless steel. Furthermore, based on the estimated values for the mean free path (MFP), the half-value layer (HVL), and the effective neutrons removal cross section (R), sample S5 with the greatest chromium content (17.68%) is shown to be a good candidate for gamma shielding rather than neutron shielding.

Isotope signature and elemental characteristics of subsurface formations around deep-laying coal seams probed by means of atomic and nuclear-based techniques.

A systematic investigation on the isotopic and elemental signature, for both stable and radioactive elements, and mineral contents was performed to examine the characteristics of subsurface formations collected at different depths between 3.962 km and 4.115 km around deep-laying coal seams located under the Marmarica plateau in Egypt. Concentrations of major and minor oxides (Na2O, MgO, Al2O3, SiO2, SO3, K2O, CaO, TiO2, MnO, ΣFeO + Fe2O3, SrO, ZrO2, and BaO) were determined by X-ray fluorescence and dependencies among these concentrations revealed the type and sort of the formations. Organic contents were determined by Fourier Transform infrared spectroscopy to investigate the variation of the CO/CC bonding ratio with depth. Rare earth elements (REE), specifically Y, Sc, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu were determined by inductively coupled plasma mass spectrometry while actinoids were detected by the radioactive decay of its daughter nuclei. The results showed a high trapping of REE elements and actinoids in layers above the coal seams which indicates the occurrence of aqueous flow followed by possible sorption in these layers. The mobility of the fluid was investigated using the process radioactive decay series between Ra226 and Ac228 from one side and their daughters from the other side.

Assessment of erosion rate in a rainfed agricultural area on the Northwestern coast of Egypt using 137Cs measurements.

In the present work, the use of the fallout radionuclide 137Cs as a tracer for estimating soil redistribution rates over the past 60 years was tested in Egypt at an agricultural field with a smooth slope (0-10%) located in Ras El-Hekma on the Northwestern coast. The average annual soil erosion rate was derived from 137Cs inventories (Bq m-2) and by using the conversion Diffusion and Migration Model (DMM). The activity concentrations of 137Cs with uncertainty ranging between 7.5 and 20.9% were measured using HPGe gamma spectrometry. Approximately exponential shape for the distribution of 137Cs activity concentration was observed within the upper 20 cm of the soil profile associated with the reference site while for the study sites, the 137Cs depth distribution profiles indicate generally an increase of activity reaching a maximum peak of 137Cs usually at a depth of 10-15 cm followed by an abrupt exponential decrease of 137Cs activity concentration with depth. The measured average reference inventory for this area was 697 Bq m-2 with a coefficient of variation of 23%. This value is close to the estimated reference inventory using the conversion model, which was 744 Bq m-2. Transect sampling strategy was adopted at the study area where three parallel transects were chosen based on the common slope. The estimated average annual erosion rate for the three transects was found to be 7.5 t ha-1 y-1, and sediment delivery ratio was approximately 98%, which shows the moderate vulnerability of the Ras El-Hekma area to water erosion.

Ocular morphology of the fruit bat, Eidolon helvum, and the optical role of the choroidal papillae in the megachiropteran eye: a novel insight.

BACKGROUND: This work was designed to provide a morphologic, morphometric and histochemical description of the eye of the African straw-coloured fruit bat (Eidolon helvum). An explanation of the optical role of the choroidal papillae in the vision of megachiropteran bats was provided. MATERIALS AND METHODS: Enucleated eyes of captured fruit bats were measured and processed for light microscopy. RESULTS: Typical gross features of the mammalian eye including an anterior transparent cornea, posterior whitish sclera and a golden-brown iris surrounding a round pupil were observed in the eye. Presence of undulating retina typically found in megachiropterans was also seen. The ratio of mean corneal diameter to mean axial eye diameter was 0.58 ± 0.08. The histochemical investigation of the eye indicated the presence of mucins, proteoglycans, hyaluronic acid, glycogen and/or glycoproteins in the corneal, scleral, choroidal and retinal tissues. CONCLUSIONS: The presence of reflective materials of the tapetum lucidum on the undulating retina was shown to be a morphological adaptation for increased light sensitivity as each parabolic surface of the choroidal papillae served as a convex mirror, reflecting the light rays to the adjacent parabolic surface, thus sensitising photoreceptors in affected regions. This phenomenon thus empowers megachiropteran bats with improved scotopic visual capability and could explain why most of them are reliant on their vison without the need for echolocation.

Ultrastructural features on the oral cavity floor (tongue, sublingual caruncle) of the Egyptian water buffalo (Bubalus bubalis): gross, histology and scanning electron microscope.

BACKGROUND: The present work was focused on the evaluation of morphological characteristics of the lingual caruncles and tongue with its papillae of Egyptian water buffalo (Bubalus bubalis) using gross examination, light and scanning electron microscopy. MATERIALS AND METHODS: The ventral surface of the sublingual caruncle carried a small opening of the duct of both monostomatic and mandibular salivary gland. The lingual mucosa of dorsal, lateral border and, to some extent, of ventral surface of apex had lingual papillae (filiform, fungiform), while the lingual mucosa of the lingual body especially at torus linguae had conical papillae, but circumvallate papillae observed at the caudal part of body and root. The dorsal surface of the apex and body carried numerous long, thread-like, with blunt apex, caudally directed filiform papillae that covered with keratinised scales without secondary papillae. RESULTS: The degree of keratinisation classified filiform papillae into rostral part of high keratinisation and caudal of less keratinisation. Conical papillary surface carried exfoliated epithelium with longitudinal groove on its rostral surface and carried secondary papillae. Fungiform papillae were scattered among filiform papillae on the dorsal and ventral surface of the apex and its convex surface had exfoliated keratinised epithelium. Circumvallate papillae were surrounded by circular deep groove bordered by vallum that carried small secondary papillae that ended into the primary groove. Taste buds of circumvallate papillae opened in the lateral lining epithelium facing the groove. CONCLUSIONS: Von Ebner's glands were observed in computed tomography under papillae especially toward the groove and their ducts open into the base of the groove.

Morphology of the lips, cheeks, and the hard palate of the Egyptian water buffalo (Bubalus bubalis): a focus on histological, histochemical, and ultrastructural aspects.

BACKGROUND: The available data is scanty about Egyptian water buffalo lips, cheeks, and palate. AIMS: The current investigation was focused on describing the morphology of the lip, cheek, and palate. METHODS: Our study included the gross, light, and electron microscopic examinations of ten heads of the Egyptian water buffalos. RESULTS: The nasolabial plate surface carried numerous scales of keratinized epithelium. Internal labial surface and labial mucocutaneous junctions were covered with stratified squamous keratinized epithelium. Two types of hair follicles in the dermis included ordinary and cavernous types characterized by cavernous space. The conical papillae on the internal aspect of the oral commissure were projected from the mucous membrane. Seromucous glands were occasionally observed under the oral mucous membrane of the commissure and gave positive PAS and AB. Conical papillae density on the inner cheek surface had some variations: the rostral part had large papillae, while the dorsal part had numerous papillae than the ventral part, the caudal part had a smaller number of papillae, while the middle part was devoid of papillae. Parotid duct opening in the buccal vestibule was without papillae. Conical papillae had two surfaces; the rostral surface was highly keratinized than the caudal one. The buccal gland was a compound tubuloacinar mixed (mucoserous) gland and mucus acini only reacted to PAS and AB. The oral surface of palatine rugae was covered with highly keratinized epithelium than the aboral surface. Palatine glands showed PAS and AB positive. CONCLUSION: The result describes the relationship between the available food particles, environmental conditions and the lip, cheek, and palate appearance, and structure.

Pregnancy outcomes among Syrian refugee and Jordanian women: a comparative study.

AIM: To compare pregnancy outcomes of Syrian refugee women and Jordanian women. BACKGROUND AND INTRODUCTION: In the past few years, thousands of Syrians fled Syria to neighbouring countries such as Jordan as a result of the continuing conflict in their country. Pregnant refugee women are facing many difficulties that increase the prevalence of antenatal complications. However, there is limited awareness of whether Syrian refugee women have different risks of pregnancy outcomes than Jordanian women. METHODS: Using a retrospective cohort design, we examined pregnancy outcomes for Syrian refugee (N = 616) and Jordanian women (N = 644) giving birth at two governmental hospital in northern Jordan, between 1 January 2014 and 31 December 2014. A checklist of 13 variables was utilized. The primary outcome measures were delivery by Caesarean section, maternal complications, low birthweight (<2500 g), APGAR score and preterm delivery (<37 weeks' gestational age). RESULTS: Statistical analysis revealed that refugee mothers had a significant increase in the rate of Caesarean section and higher rate of anaemia, a lower neonates' weight and APGAR scores when compared to their Jordanian counterparts. DISCUSSION: Results were congruent with findings from other studies in the region and worldwide. CONCLUSION AND IMPLICATIONS FOR NURSING AND HEALTH POLICY: Minimizing inequalities in pregnancy outcomes between Syrian refugees and Jordan women is a healthcare priority. The findings could guide the planning and development of health policies in Jordan that would help to alleviate the situation regarding refugee populations. Action is required by policy makers, specifically targeting public and primary healthcare services, to address the problem of adequately meeting the needs for antenatal care of this vulnerable population.

Investigation of the immediate pre-operative physical capacity of patients scheduled for elective abdominal surgery using the 6-minute walk test.

OBJECTIVES: To evaluate the effects of repetition of the 6-minute walk test in patients scheduled to undergo abdominal surgery within the next 48 hours, and to verify the physical capacity of these subjects before surgery. DESIGN: Cross-sectional study. SETTING: University teaching hospital. PARTICIPANTS: Forty-two patients scheduled for elective abdominal surgery within the next 48 hours. OUTCOME MEASURES: Distance walked in the 6-minute walk test, heart rate, peripheral oxygen saturation, dyspnoea and leg fatigue. RESULTS: Thirty-one patients (74%) were able to walk for a longer distance when the test was repeated. In these subjects, the mean increase in distance walked was 35.4 [standard deviation (SD) 19.9]m. Heart rate, dyspnoea and leg fatigue increased significantly over time on both tests (P<0.05). The mean heart rate at the end of the sixth minute was significantly higher on the second test (P=0.022). Peripheral oxygen saturation remained above 90% in both tests. The furthest distance walked was, on average, 461.3 (SD 89.7)m. This value was significantly lower than that predicted for the sample (P<0.001). CONCLUSION: Patients scheduled to undergo abdominal surgery were able to walk further when they performed a second 6-minute walk test. Moreover, they showed reduced physical ability before surgery. These findings suggest that repetition of the 6-minute walk test may increase the accuracy of the distance walked, which is useful for studies assessing the physical capacity of patients undergoing abdominal surgery.

Factors associated with birth weight inequalities in Jordan.

BACKGROUND: Birth weight is a good indicator of mothers' and neonates' nutritional status, and it contributes to the newborn baby's survival, health, growth and development. AIM: This study identified social factors associated with differences in the mean birth weight of newborn babies in Jordan. METHODS: This retrospective study analysed medical records to determine possible risk factors associated with differences in newborn BW in the Irbid governorate of Jordan. All full-term singleton births during the year 2010 were reviewed. Abstracted data included mother's age, educational level, and monthly family income. Newborn information included birth weight, gender and birth order. RESULTS: A total of 5414 full-term singleton births were included. Of these, 15.1% were low birth weight, 73.6% were normal birth weight, and 11.3% were high birth weight. Bivariate analysis of variance revealed that low mean birth weight was associated with female gender, first-born babies, higher maternal age (>35 years), lower educational level and lower income (<500 JD). Multivariate analysis of variance revealed that mean birth weight was lower in female infants, first-born infants, infants of less educated mothers, higher age and low monthly income. LIMITATIONS: The findings can be generalized to full-term singleton pregnancies in countries who share similar cultural and traditional values. CONCLUSION: Education of mothers is a modifiable variable that can positively influence birth weight, particularly in the case of female and first-born infants. IMPLICATION FOR NURSING AND HEALTH POLICY: The findings inform our understanding of some social factors affecting birth weights of neonates in Jordan and development of effective public health interventions that could reduce the adverse effects of such factors on newborn birth weight. Preconception and antenatal care is also important for early detection of such possible risk and targeting mothers who require early interventions and support.

Localization of the epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) in the bovine testis.

In the last few decades, several growth factors were identified in the testis of various mammalian species. Growth factors are shown to promote cell proliferation, regulate tissue differentiation, and modulate organogenesis. In the present investigation we have studied the localization of EGF and EGFR in the adult bovine testis by means of immunohistochemical method. Our results demonstrated that EGF and EGFR were localized solely to the bovine testicular germ cells (spermatogonia, spermatocytes, and round spermatids). In contrast, the somatic testicular cells (i.e., Sertoli, Leydig, and myofibroblast cells) exhibited no staining affinity. EGF and EGFR were additionally detected in the epithelial lining of straight tubules and rete testis. Interestingly, the distribution of EGF and EGFR in the germ cells was mainly dependent upon the cycle of the seminiferous epithelium since their localization appeared to be preponderant during the spermatogonia proliferation and during the meiotic and spermiogenic processes. In conclusion, such findings may suggest that EGF and EGFR are important paracrine and/or autocrine regulators of spermatogenesis in bovine.

The therapeutic potential of statins in neurological disorders.

Statins are currently among the most commonly prescribed agents for the prevention of cardiovascular disease. Statins reduce serum cholesterol levels by reversibly inhibiting 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol biosynthesis, in the nanomolar range. Mounting evidence suggests that in addition to their vascular effects such as stabilization of atherosclerotic plaques and decreased carotid intimal-medial thickness, statins have additional properties such as endothelial protection via actions on the nitric oxide synthase system as well as antioxidant, anti-inflammatory and anti-platelet effects. These effects of statins might have potential therapeutic implications in various neurological disorders such as stroke, Alzheimer's disease, Parkinson's disease, multiple sclerosis and primary brain tumors. In this review, the major protective mechanisms of statins and their applicability to the treatment of neurological disease are summarized. Although further experiments are required, currently available data would seem to indicate that clinical trials to determine the safety and efficacy of statins in a number of disorders are warranted.

[Sequelae of intra-articular calcaneal fractures: patterns and management]. / Chirurgie des séquelles des fractures du calcanéum: à propos de 24 cas.

PURPOSE OF THE STUDY: We reviewed retrospectively 24 feet with sequelae of transtalar process fractures of the calcaneum in order to identify the lesion pattern and determine optimal management options, both for acute and sequelar lesions. MATERIAL AND METHODS: There were fourteen men and nine women, mean age 42 years (19-73). Twenty-three had subtalar osteoarthritis, eight had calcaneocuboid osteoarthritis, and fifteen had lateral submalleolar conflicts. There were twelve fibular tendon dislocations or fissurations, three tarsal tunnel syndromes, and two plantar splinters. Prior to treatment, all patients complained of pain. Preoperatively, walking distance was less than 500 m for thirteen patients, 2000-3000 m for four, and greater than 3000 m for five. Mean subtalar joint motion was 30% (0-100%) compared with the healthy side and mean frontal misalignment of the rear foot was 6 degrees valgus. Physical examination, podoscopy and x-rays were obtained in all patients. The Kitaoka score was noted. RESULT: Mean follow-up was 36 months (24-72). Sequelae were treated with a single procedure or with combinations: subtalar arthrodesis (n = 23) including one in association with calcaneocuboid arthrodesis, tension on fibular tendons (n = 7), neurolysis of the posterior tibial nerve (n = 3), resection of plantar splinters (n = 2), resection of the lateral shell (n = 14), and osteotomy (n = 2) to lower the greater tubercle of the calcaneum because of pain when wearing shoes. The mean Kitaoka function score was 31.7/100 (14-79) preoperatively. After treatment, the mean score was 81.7/100 (31-94), giving a 73.2% gain. The outcome was considered good in sixteen feet, fair in six, and poor in two. Mean walking distance was greater than 3000 m for 18 patients. Mean frontal misalignment of the rear foot under loading was 4.5 degrees valgus and the podoscopy demonstrated flat foot in thirteen patients. Three subtalar arthrodesis required revision for nonhealing. DISCUSSION: Initial treatment of a fracture, particularly an articular fracture, of the calcaneum must avoid disabling postoperative pain and shoe wearing problems. These sequelae basically concern: subtalar and calcaneocuboid arthritis, lateral submalleolar conflict, fibular tendon injury, plantar splinters, tarsal tunnel syndrome, loss of height, and misalignment of the rear foot. At the sequelar stage, the physical examination is primordial to confirm the lesion and search for any complication which could develop later postoperatively when walking distance becomes longer. For nine patients with residual pain, four resulted from lesions which were missed at the preoperative physical examination. Arthrodesis of the subtalar joint should be preferred over realignment of the rear foot and can be associated with the treatment of conflicts. This management scheme allows treating during a single operative time all sequelae, thus limiting recovery time. A scan of the ankle and foot with or without opacification of the fibular tendons is needed to confirm the physical examination which, for us, remains the key to successful surgery.

[Twenty nine shoulder reconstructions after resection of the proximal humerus for neoplasm with mean 7-year follow-up]. / Les reconstructions après résection tumorale de l'extrémité supérieure de l'humérus.

PURPOSE OF THE STUDY: Techniques available for shoulder reconstruction after resection of a tumor of the proximal humerus include scapulohumeral arthrodesis, humerus prosthesis with or without an allograft, inverted prostheses, and massive allografts. The purpose of this study was to review clinical and radiological outcomes in a series of 29 patients (20 men and 9 women) who underwent resection-reconstruction of the proximal humerus and to establish from these cases a decision making algorithm for therapeutic indications as a function of tumor invasion. MATERIAL AND METHODS: The tumors were 20 chondrosarcomas, five osteosarcomas, two Ewing sarcomas and one malignant hemangiopericytoma. In 17 patients epiphyso-metaphyseal or epiphyso-metaphyso-diaphyseal resection was performed with preservation of the abductor muscles (type S34A or S345A according to the Musculoskeletal Tumor Society classification). For 12 patients epiphyso-metaphyseal or epiphyso-metaphyso-diaphyseal resection was performed without preservation of the abductor muscles (type S34B or S345B). Reconstruction was achieved using a centromedullary cemented nail in one patient, scapulohumeral arthrodesis in three, a massive humerus prosthesis in 15, and composite humerus prosthesis in three and an inverted prosthesis in seven. The functional score of the Musculoskeletal Tumor Society (MSTS) and standard x-rays were used to assess outcome. RESULTS: Mean follow-up was 85 months (range 16-300). The mean MSTS score was 88% for inverted prostheses, 76% for composite prostheses, 72.6% for massive prostheses, 75% for scapulohumeral arthrodeses, 67% for massive prostheses, and 80% for cemented centromendullary nail. Five patients died from their malignant disease and one from another cause. Four patients are alive but with active disease after a mean follow-up of 108 months and 19 patients (65.5%) are alive and free of locoregional recurrence or metastasis after a mean 83.5 months. We had 28 complications. Glenohumeral instability was the most frequent (11 cases). DISCUSSION: Resection of the upper portion of the humerus should be performed to achieve cancerologically satisfactory tumor resection and enable shoulder resection, if possible, with preservation of a viable and functional abductor system. The functional outcome after such reconstruction depends on the type of bony resection, but also on the sacrifice of the rotator cuff and the deltoid muscle. In light of our experience and results in the literature, we advocate, despite the small number of cases for the different reconstructions, the following decision-making algorithm after resection of the proximal humerus without joint invasion: when the resection removes the rotator cuff and the deltoid (or the axillary nerve), there are two options: scapulohumeral arthrodesis or massive humerus prosthesis for patients who do not desire a complex therapy with a long postoperative period; when the resection preserves the rotator cuff and/or the deltoid muscle, reconstruction can be achieved with a composite (inverted or not) prosthesis with suture of the cuff tendons. We prefer the inverted composite prosthesis; if the deltoid muscle can be preserved but not the rotator cuff, the composite inverted prosthesis appears to be the most logical solution, but scapulohumeral arthrodesis can be proposed in selected cases.

Ipsilateral fibular transposition in tibial nonunion using Huntington procedure: a 12-year follow-up study.

Eleven patients (10 men and 1 woman) with a mean age of 32 years (range: 16-61 years) and a mean follow-up of 12 years (range: 2-21 years) were studied retrospectively after ipsilateral fibular transposition. The cause of tibial nonunion was a motor vehicle collision (MVC) in eight patients, a fall from a window in one, an adamantinoma in one, and osteomyelitis in one. There was one type I and eight type IIIb open fractures according to the Gustilo classification, and the nonunion was infected in seven patients. Healing of the tibial defect was obtained in eight patients, after a mean interval of 10.5 months. In the patient with the adamantinoma, resection of the tumour left a 22 cm defect in the tibia. Two patients required amputation for acute local infection. Seven of the eight patients in whom tibial union was achieved were able to walk with no aids. The authors conclude that transposition of the ipsilateral fibula is a valuable component of the therapeutic armamentarium and a salvage procedure for patients with multi-operated, infected or uninfected, tibial nonunion.

Brain blood flow in the nitroglycerin (GTN) model of migraine: measurement using positron emission tomography and transcranial Doppler.

Nitroglycerin has been widely used as a model of experimental migraine. Studies combining measurement of flow velocity using transcranial Doppler (TCD) concurrently with measures of cerebral blood flow (CBF) are uncommon. We report the results of a study combining TCD and positron emission tomography (PET). Healthy volunteers with no personal or family history of migraine underwent measurement of CBF using H215O PET, and velocity using TCD. Measurements were done at baseline, and following i.v. nitroglycerin at 0.125, 0.25 and 0.5 micro g/kg per min. Subcutaneous sumatriptan (6 mg) was injected, with CBF and velocity measured 15, 30, and 60 min later. Nitroglycerin was terminated and measurements obtained 30 min later. Six male and six female subjects were studied. Nitroglycerin increased global CBF while flow velocities decreased. Sumatriptan did not have a significant effect on these values. Regions of increased flow included the anterior cingulate, while regions of decreased flow included the occipital cortex. Our data suggest that nitroglycerin induces regional changes in CBF that are similar to changes reported in spontaneous migraine, but produces distinctly different effects on global CBF and velocity.

A review of telemedicine.

Moving the information instead of the patient is often sufficient and telemedicine is a useful and potentially powerful tool which fulfils this idea. It has changed the classical form of health-care delivery by providing those people living in rural and remote areas with comparable services to those in urban areas. Equally, remote hospitals can obtain specialist consultations and diagnosis without the need for the patient to travel. We have reviewed the present status of telemedicine and its future possibilities.

Aneurysm of the coeliac artery.

A case of coeliac artery aneurysm associated with multiple splanchnic artery aneurysms is reported. This abnormality involved the gastroepiploic and hepatic arteries. The coeliac artery was ligated at laparotomy and the liver revascularized by direct anastomosis of the common hepatic artery to the aorta. Arteriography on the fifth postoperative day showed a satisfactory result. The surgical problems associated with aneurysms of the coeliac artery are reviewed.

[Postoperative vascular infections. A pathognomonic x-ray computed tomographic sign]. / Infections vasculaires post-opératoires. Un signe tomodensitométrique pathognomonique.

The potential gravity of post-operative vascular infection makes early diagnosis essential. We report a case where this diagnosis was made on CT findings alone, in the absence of any other signs of infection. Rapid intervention led to complete cure. Beyond the immediate post-operative period, the presence of gas on the CT scan is rare but pathognomonic in the absence of a cutaneous fistula. The presence of this sign is therefore sufficient to indicate that reintervention is mandatory.