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Understanding morphological changes of nanoparticles in solution is essential to tailor the functionality of devices used in energy generation and storage. However, we lack experimental methods that can visualize these processes in solution, or in electrolyte, and provide three-dimensional information. Here, we show how X-ray ptychography enables in situ nano-imaging of the formation and hollowing of nanoparticles in solution at 155 °C. We simultaneously image the growth of about 100 nanocubes with a spatial resolution of 66 nm. The quantitative phase images give access to the third dimension, allowing to additionally study particle thickness. We reveal that the substrate hinders their out-of-plane growth, thus the nanocubes are in fact nanocuboids. Moreover, we observe that the reduction of Cu

Nature Communications 12(1), 4429 (2021). doi:10.1038/s41467-021-24557-z, The key to fabricating complex, hierarchical materials is the control of chemical reactions at various length scales. To this end, the classical model of nucleation and growth fails to provide sufficient information. Here, we illustrate how modern X-ray spectroscopic and scattering in situ studies bridge the molecular- and macro- length scales for assemblies of polyhedrally shaped CoO nanocrystals. Utilizing high energy-resolution fluorescence-detected X-ray absorption spectroscopy, we directly access the molecular level of the nanomaterial synthesis. We reveal that initially Co(acac)$_3$ rapidly reduces to square-planar Co(acac)$_2$ and coordinates to two solvent molecules. Combining atomic pair distribution functions and small-angle X-ray scattering we observe that, unlike a classical nucleation and growth mechanism, nuclei as small as 2 nm assemble into superstructures of 20 nm. The individual nanoparticles and assemblies continue growing at a similar pace. The final spherical assemblies are smaller than 100 nm, while the nanoparticles reach a size of 6 nm and adopt various polyhedral, edgy shapes. Our work thus provides a comprehensive perspective on the emergence of nano-assemblies in solution., Published by Nature Publishing Group UK, [London]

Rapporter les difficultes et les ecarts par rapport aux recommandations dans la prise en charge des cancers du rectum dans les pays en voie de developpement: cas de l’Hopital national de Niamey (Niger). Il s’agissait d’une etude retrospective sur quatre ans concernant 36 patients admis pour prise en charge d’un cancer du rectum ayant eu au prealable un diagnostic histologique. Il s’agissait de 21 hommes et de 15 femmes. L’âge moyen de nos patients etait de 44,5 [±10,5] ans avec des extremes allant de 27 a 76 ans. La moitie provenait de milieux defavorises. L’adenocarcinome lieberkuhnien etait le type histologique le plus frequent (91,6 %). Cependant, une tumeur stromale gastro-intestinale, un carcinome epidermoide et un carcinome mucineux ont ete retrouves. Dans 77,7 % des cas, la lesion siegeait sur le bas et/ou le moyen rectum. Le bilan diagnostique etait fonde sur l’endoscopie digestive pratiquee chez 77,7 % des patients et le scanner pratique chez 27,7 % des patients. La radiographie pulmonaire etait l’examen de bilan d’extension a distance le plus souvent realise (97,2 %). Il n’y a pas eu d’echoendoscopie ni d’imagerie par resonance magnetique. Un de nos patients avait eu une radiochimiotherapie neoadjuvante et quatre (11,1 %) une chimiotherapie adjuvante seule. La resection anterieure du rectum etait l’intervention la plus realisee (39,8 %), suivie d’une anastomose colorectale chez la moitie des operes. La mortalite a un an etait de 6,1 %. L’absence de moyens diagnostiques et l’absence et/ou l’inaccessibilite des moyens therapeutiques sont a la base d’une reelle « fracture medicale ».

Rapporter les resultats du traitement des volvulus du colon sigmoide (VCS) a l’hopital national de Niamey et proposer une classification therapeutique. Il s’agissait d’une etude retrospective, descriptive et analytique sur dix ans incluant tous les adultes traites pour VCS a l’hopital national de Niamey. Une association entre la morbimortalite et les variables a ete recherchee, et les resultats obtenus ont ete analyses et interpretes en fonction des donnees de la litterature afin de proposer une classification therapeutique. La serie incluait 168 patients, soit 17,31 % des occlusions intestinales et 2,64 % des urgences abdominales. Il s’agissait de 166 hommes et de deux femmes. L’âge moyen des patients etait de 50,80 ans (±15,52). Le delai moyen de consultation etait de 4,18 jours (±2,85). La douleur abdominale etait le maitre symptome present chez tous les patients. Le diagnostic paraclinique etait essentiellement fait par une radiographie de l’abdomen sans preparation. Un noeud ileosigmoidien etait retrouve chez 4,76 % des patients. Le taux de necrose etait de 22,02 %. Une colectomie selon Hartmann etait realisee chez 68,45 % des patients, suivie d’une colectomie ideale (25,60 %). La morbidite globale etait de 14,28 %, et 7,15 % des patients etaient decedes dont 5,95 % apres colectomie selon Hartmann. La survenue de complications etait influencee par la necrose (p = 0,04) et le long delai de consultation (p = 0,04). La mortalite etait influencee par la colectomie selon Hartmann (p = 0,01). L’analyse de nos resultats a la lumiere de la litterature nous a permis de definir quatre groupes therapeutiques de patients. La determination de quatre groupes de patients pourrait aider a la gestion du VCS.

Introduction: The aim of this work was to highlight the therapeutic and prognostic difficulties between a laparoscopic cholecystectomy for acute gallstone cholecystitis (CAL) and uncomplicated symptomatic vesicular lithiasis (LVS) as well as the reasons for conversion to laparotomy. Patients and Methods: This was a prospective comparative and analytic study over 18 months. Patients admitted and operated for CAL or LVS in the A Surgery Department of the National Hospital of Niamey (HNN) were included. Results: The study involved 61 patients divided into two groups. Group 1 (30 patients) corresponding to patients operated for CAL, group 2 (31 patients) corresponding to patients operated for LVS. Laparoscopic cholecystectomy accounted for 61% of all cholecystectomies performed and 1.45% of surgical activity during the same period. The average age in group 1 was 43.7 years with extremes of 14 and 61 years. In group 2, the average age was 38.9 years with extremes ranging from 12 to 55 years. Women were predominantly represented with 63.3% and 96.7% respectively for groups 1 and 2. Patients were overweight in 9 cases for group 1 (30% of cases) and 12 cases in group 2 (38%), 7% of cases). Hepatic colic was the main sign of appeal in all patients in both groups. In group 1; 26 out of 30 cases or 86.7% of cases had leukocytosis, whereas in group 2, leukocytosis was normal in 30 cases, ie 96.8% of cases. Accessibility of the vesicle was difficult in 73.3% of cases in group 1 against 22.6% of cases in group 2. The vesicle was distended and necrotic in groups 1 in 76.7% and 10 respectively. % of cases. On the other hand, in 25.8% of cases, the vesicle was distended and without any necrosis in group 2. The rate of conversion to laparotomy was 6.55% (4 cases) and exclusively concerned group 1. Operative follow-up immediate outcomes were simple in 98.34% of cases. The complications involved 2 patients in group 1 (1.66% of the total), including parietal suppuration and biliary leakage. Mean operative time was 68.7 min in group 1 versus 41.6 min in group 2. Mean duration of hospitalization was 4.3 days with extremes between 2 and 10 days in group 1 versus1,7 days with extremes ranging from 1 to 7 days in group 2. Mortality was zero. Conclusion: In recent years, laparoscopic surgery has made remarkable progress in Niger. Laparoscopic cholecystectomy seems to be more difficult to perform with significant morbidity in the case of CAL than LVS. The risk of per and postoperative complications can be estimated from the clinical data (acute cholecystitis or symptomatic vesicular lithiasis) and the surgeon's experience. In a cholecystectomy that lasts more than 2 hours, the cumulative risk of complications is higher

Introduction: Arterial aneurysms affect 7 to 8% of people over 65 in the West and are the 2nd leading cause of death in these countries. In Africa this frequency is poorly evaluated. The objective of this work is to report the management of arterial aneurysms at the National Hospital of Niamey (HNN). Patients and methods: This was a retrospective, descriptive study over a period of eight (8) years from January 2009 to December 2016, performed in the surgical departments of the National Hospital of Niamey. Included in the study were patients of both sexes, hospitalized and / or operated for arterial aneurysm. Not included were patients treated for arterial aneurysm with incomplete records or those concerning the neurosurgical sphere. Results: During the study period, 17,748 patients were hospitalized in the general surgery departments, including 16 patients for arterial aneurysm, or 0.09% of surgical pathologies. There were 13 men (81.25%) and 3 women (18.75%), or a sex ratio of 4.33. The average age was 55.75 years with extremes ranging from 25 years old to 90 years old. The circumstances of discovery of the aneurysms were swelling of the antero-internal aspect of the thigh in 7 cases (43.75%), abdominal mass 6 cases (37.50%), then 2 cases (12.50%) of chest pain and incidental discovery in 1cas (6.25%). The most common risk factor was high blood pressure with 43.75% (7 cases). The aneurysm sat on the femoral artery in 43.75% (n = 7), of which 6 on the deep femoral and 1 on the superficial femoral, on the infrarenal aorta in 31.25% (n = 5), on thoracic aorta 12.50% (n = 2), on the iliac artery 12.50% (n = 2). For the diagnosis the angioscanner is realized in all the patients and in addition Doppler ultrasound in 43, 75% of cases. Twelve (12) patients benefited from curative surgical intervention by prosthetic graft by PTFE in 58.33% of cases and by Dacron in 41.66%. The average stay was 29.75 days and the immediate operative followup was complicated by thrombosis in 12.5% and parietal suppurations in 6.25%. We recorded two (2) deaths, ie 12.5% among non-operated patients. Conclusion: Arterial aneurysms are rare diseases at the HNN. Conventional surgery is the treatment performed in our patients. The postoperative course was simple in most cases.

The arteries and veins of the left vagus (VN) and left recurrent laryngeal (RLN) nerves from the thoracic inlet to the subaortic region are described following vascular casting with red colored latex in 6 adult fresh non-embalmed cadavers. In all specimens the anterior bronchoesophageal artery supplied at least one vessel to the VN and RLN in the subaortic region. For the RLN other arterial sources were arteries arising from the aortic arch in 1 specimen, the subclavian artery in 3 specimens, the first intercostal artery in 1 specimen, and the inferior thyroid artery in all specimens. For the VN other arterial sources were arteries arising from the aortic arch in 2 specimens and the inferior thyroid artery in 1 specimen. For both the VN and RLN the veins were located under the pleura and directed towards the internal thoracic vein anteriorly and the thoracic intercostal veins posteriorly. In conclusion, the inferior thyroid artery at the thoracic inlet for the RLN and the anterior bronchoesophageal artery are the more consistent vessels supplying the VN and RLN. Vascular damage occurring during mediastinal lymph node excision to the VN and RLN, especially in the subaortic region, may explain postoperative vocal fold paralysis.

Inguinal hernia is a most common pathology in paediatric practice. Diagnosis is usually easy and rarely requires paraclinic exams (sonography). The main risk is strangulation, which can be complicated by testicular or ovarian atrophy. This justifies early surgical treatment. Operative mortality rate is almost nil. There is a risk of recurrence and of occurrence of contralateral hernia.

West Africa has probably the highest levels of maternal mortality in the world. A new method has been developed by the Institute of Tropical Medicine of Antwerp (Belgium) that gives an estimate of the Uncovered Obstetrical Need. This technique tested in different Western African countries has been now evaluated also in an urban medical district in Niamey, capital of Niger, for the year 1999. The uncovered obstetrical need has been estimated at 15 major Obstetrical Interventions for this period; this means that 15 pregnant women didn't undergo a major surgical intervention necessary to save their life and that they probably died because of this non-intervention. We met quite a lot of problems with this new method: (i) the first problem is related to the difficulty to obtain correct demographic information: it is very difficult to estimate population growth in urban african areas, present population and number of attended births. (ii) The second difficulty came from sociocultural habits: primipare women in Niger go back to their family to deliver (and the place where their family lives is not necessarily the same as the place where they stay with their husband); it is quite possible that a number of primipare women needing a major surgical intervention didn't undergo this intervention because they delivered in their home village (and perhaps died there). (iii) At last, the estimation of a reference rate (calculated at 0.9% for Niger) implies that all women needing a major obstetrical intervention in Niamey, and having a theoretical easy access to medical infrastructures (first line as second line hospitals) present themselves when having a major obstetrical problem. This is probably "wishful thinking". The interest of this new method lies in the fact that it is a cheap technique and easy to put into practice ... provided that one disposes of medical infrastructures that collect correctly all necessary medical information.

The aim of this study was to determine the outcome for patients treated for strangulated inguinal hernia with intestinal resection for gangrenous. Between May 1997 and November 1998, 124 patients were admitted to our hospital for acute intestinal obstruction; 34 of them were treated for strangulated inguinal hernia and 17 underwent an intestinal resection. The outcome for the 34 patients with strangulated hernias were analysed retrospectively. Strangulated inguinal hernia occurred in young patients (80 per cent of our patients were aged under 45 years) and strangulation had evolved over an average of 2.5 days. The clinical picture was simple strangulated hernia in 10 cases, with intestinal obstruction syndrome in 15 cases, peritonitis in 3 cases, phlegmonous hernia in 4 cases, and fistulae in one case. Fifty per cent of patients had intestinal resection with poor means of resuscitation. This resection concerned 80 per cent of patients with strangulation lasting over 72 hours. Surgical repair of hernia was performed in 24 cases at the same time. There were numerous complications, notably: wound sepsis (16 cases), post-operative peritonitis (3 cases) and multiple system failure (12 cases). The mortality rate was 40 per cent and concerned 86 per cent of patients with small bowel necrosis and 89 per cent of those admitted after 96 hours of strangulation.

Acute appendicitis remains one of the most frequent emergencies in abdominal surgery. Surgery is usually straightforward and prognosis excellent. However, outcome depends essentially on how soon diagnosis is made. In Niger, the 1990s were marked by the development of private medicine and the deterioration of services in state health structures (health centres and hospitals). The goal of this prospective study, carried out over 24 months (March 1997-March 1999) was to analyse existing appendicitis prognosis in our country. The study population was made up of 362 patients and we based our survey on a number of factors found in the medical literature, and in particular on a similar study conducted in the same hospital in 1989 by another group of surgeons. Delays in diagnosis and thus therapy still today tends to transform prognosis for simple acute appendicitis into that of peritonitis. The numerous and varied post-operative complications keep the mortality rate at 4%.

Quinine by intramuscular or intrarectal injection has been found to be the best treatment for malaria in Niger, particularly in field health centres where the use of solutions can pose problems. There have been several reports of complications following injections, usually due to technical error or to the toxic side effects of quinine. In our hospital, we treated two such rare complications consisting of a case of coxal osteoarthritis induced by intramuscular injection and a case of anorectal necrotising induced by intrarectal injection. The occurrence of such life-threatening events could be reduced in frequency by teaching health personnel about techniques of quinine administration as well as its dangers.

The influence of various modes of carrying a load of 16 kg (15.69 DaN) on the static positioning of the pelvic girdle and the thoracic and lumbar segments of the spine was examined in seven male subjects. The displacement of cutaneous markers attached to easily palpable skeletal landmarks was recorded using 4 CCD cameras; the data acquired were analysed using an optoelectronic technique (SAGA3). The subjects stood upright on an AMTI biomechanical force platform, from which the ground reaction forces enabled displacements of the centre of gravity axis and thus the moment of the mass carried to be determined. The modes of load carriage examined were: 1) in a case in the left hand; 2) in a case in the right hand; 3) equally in two cases; 4) on the head; 5) in a rucksack; and 6) in an anterior bag. The results showed displacements of the pelvic girdle, the caudal and cranial lumbar segments, and the caudal and cranial thoracic segments in the three orthogonal planes (sagittal, frontal and transverse). The influence of the moment created by the load was seen in the statokinesigrams. The use of external markers using an optoelectronic technique, in association with the ground reaction forces, enables the mode of load carriage to be determined. The results show that the influence of the moment exerted by the mode of load carriage on the gravity axis has important ergonomic consequences.

Inguinal hernia is a most common pathology in paediatric practice. Diagnosis is usually easy and rarely requires paraclinic exams (sonography). The main risk is strangulation, which can be complicated by testicular or ovarian atrophy. This justifies early surgical treatment. Operative mortality rate is almost nil. There is a risk of recurrence and of occurrence of contralateral hernia.

In order to precise the different prognosised factors of the acute intestinal invagination of the nursling, authors hereby report results of a prospective study lead in the department of general surgery during the period of January 1989 to August 1990. Eleven nursling have been operated during that period. The study of their files showed that the standard clinical triad of the acute intestinal invagination theoretically taught in the schools of health sciences, is never definitive. The diagnostic lateness and indeed therapeutic and the lack of adequate means of pediatric resuscitation constituted the main prognosised factors of this affection. The clinical board of the patients is that of an advanced occlusion or that of a serious peritonis. The surgical operation often consisted in an intestinal resection. The immediate mortality was heavy: 55%. The authors hereby stress the necessity of a training-informing-sensitizing of the health staff in the primary sanitary facilities and the populations.

The authors report 66 cases of peri- and postpartum cardiomyopathy. The patients' age ranged from 16 to 42 years (mean +/- SD 30 +/- 7 years). All were black women native of the western part of the Republic of Niger, Sahelian in the north, Sudanese in the south. At first examination, all had signs of congestive cardiac failure. In 67 p. 100 of the cases these signs appeared during the first six postpartum weeks. Clinical, radioscopic and echocardiographic features were always those of dilated cardiomyopathy, even when arterial pressure was high. Hypertension was present at first examination in 50.8 p. 100 of the cases, but it remained stable under treatment in 13 p. 100. These data suggest an acute postpartum hypertension. The following risk factors of the disease were identified: rural living, absence of school attendance, low family income, multiparity, identical pathology after a previous pregnancy, postpartum "quarantine" period, ritual ablutions with very hot water, large amounts of sodium in the diet, hypertension, breast-feeding and postpartum oestrogen secretion decrease. Seasonal variations were noted, with doubling of new cases during the hot and humid season. The hypothesis of a latent gravidic myocarditis is discussed: the accumulation of risk factors during the postpartum period might trigger off the clinical disease. Forty seven patients were followed up for a mean period of 15 months. Seven died, 21 (31.8 p. 100) were in complete remission and 19 in partial remission. In case of relapse, complete remission was less frequent and appeared more slowly under treatment. Persistent cardiomegaly under treatment was of poor prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)