Rethinking arithmetic for deep neural networks.

We consider efficiency in the implementation of deep neural networks. Hardware accelerators are gaining interest as machine learning becomes one of the drivers of high-performance computing. In these accelerators, the directed graph describing a neural network can be implemented as a directed graph describing a Boolean circuit. We make this observation precise, leading naturally to an understanding of practical neural networks as discrete functions, and show that the so-called binarized neural networks are functionally complete. In general, our results suggest that it is valuable to consider Boolean circuits as neural networks, leading to the question of which circuit topologies are promising. We argue that continuity is central to generalization in learning, explore the interaction between data coding, network topology, and node functionality for continuity and pose some open questions for future research. As a first step to bridging the gap between continuous and Boolean views of neural network accelerators, we present some recent results from our work on LUTNet, a novel Field-Programmable Gate Array inference approach. Finally, we conclude with additional possible fruitful avenues for research bridging the continuous and discrete views of neural networks. This article is part of a discussion meeting issue 'Numerical algorithms for high-performance computational science'.

Small infarctions of cochlear, retinal and encephalic tissue (SICRET syndrome).

PURPOSE: To report 3 new cases suggestive of SICRET syndrome. METHODS: Case reports. Three patients underwent clinical, laboratory and neuroradiological examination for recurrent retinal branch artery occlusions, encephalopathy and/or hearing loss. RESULTS: In all 3 patients the laboratory tests were unremarkable for infectious or systemic disease. All 3 cases showed retinal artery occlusions on funduscopy and fluorescein angiography. Visual acuity impairment and visual field defects were related to the retinal artery occlusion site. Variations in the presenting sign were noted in the 3 patients. The first patient (a 32 year old man) showed a documented association of small infarctions of the brain and the retina. The retinal occlusions were bilateral and 8 recurrences were observed. In the second case (a 26 year old woman) the brain was initially involved. Fluorescein angiography showed unilateral retinal artery occlusion. Cochlear manifestations were not reported. The third case (a 35 year old woman) showed initially bilateral recurrent branch artery occlusion and hearing loss without clinical signs of encephalopathy. Three recurrences were documented. CONCLUSION: SICRET syndrome is a microangiopathy that causes infarcts in the cochlea, retina, and brain of young patients, usually women. The aetiology is unknown. Clinically some infarcts may remain asymptomatic. Bilateral sensorineural hearing loss on low frequency on audiology, recurrent bilateral retinal branch artery occlusions on fluorescein angiography and small multiple areas of signal hyperintensity in white and gray matter on Brain MRI T2-weighted images are necessary for the diagnosis. Our 3 patients did not fulfill these criteria, but their disease was suggestive of SICRET syndrome. SICRET syndrome should be included in the differential diagnosis of recurrent branch artery occlusions. The clinical course is self-limited and treatment options are not codified.

[Relation between retinal pigment epithelial detachment and dye leakage in central serous retinopathy]. / Relation entre le décollement séreux de l'épithélium pigmentaire et le point de fuite dans la rétinopathie séreuse centrale.

PURPOSE: The purpose of this report is to provide supportive evidence favoring the hypothesis of choroidal hyperpermeability in central serous chorioretinopathy. PATIENTS AND METHODS: Seven consecutive patients (eight eyes) with a history of central serous chorioretinopathy were explored. Fluorescein angiography and a monochromatic frame at 640 mm was performed for all eyes. All showed dye leakage located at the rim of a retinal pigment epithelial detachment. RESULTS: Retinal pigment epithelial detachment was extrafoveal in all 8 eyes. Dye leakage was located at the nasal rim in 4 eyes, the superior rim in 2 eyes, the temporal rim in 1 and the anterior rim in the last eye. CONCLUSION: Dye leakage at the rim of pigment epithelial detachment in central serous chorioretinopathy is a strong argument for the hypothesis of a choroidal hyperpermeability. The hyperpressure crushes the overlying retinal pigment epithelium and in some areas provokes focal detachment and dye leakage at the junction of the detached and attached pigment epithelium.

Survival after malignant tumors of the orbit and periorbit treated by exenteration.

PURPOSE: In order to further assess the survival value of orbital exenteration in malignant orbital and periorbital tumors. METHODS: The charts of 44 patients exenterated for a neoplasm of the orbit or periorbit were reviewed in a retrospective study. RESULTS: The overall 4-year survival was 45%. 26 patients had free margins on histological examination and 24 patients had developed local recurrence or metastasis. Local recurrence or metastasis were significantly more common in the group with transected margins than in the group with free-margins (p= 0.01). Survival between the group of patients with local recurrence or metastasis and the group without local recurrence or metastasis showed statistically significant difference (p=0.0025). In contrast, survival between the group of patients with free margins and the group with transected margins did not show statistically significant difference (p=0.13). CONCLUSION: Surgical free margins section is a key element in successful cancer surgery but seems not the only prognosis variable.

Computation of light scattering by axisymmetric nonspherical particles and comparison with experimental results.

A laboratory prototype of a novel experimental apparatus for the analysis of spherical and axisymmetric nonspherical particles in liquid suspensions has been developed. This apparatus determines shape, volume, and refractive index, and this is the main difference of this apparatus from commercially available particle analyzers. Characterization is based on the scattering of a monochromatic laser beam by particles [which can be inorganic, organic, or biological (such as red blood cells and bacteria)] and on the strong relation between the light-scattering pattern and the morphology and the volume, shape, and refractive index of the particles. To keep things relatively simple, first we focus attention on axisymmetrical particles, in which case hydrodynamic alignment can be used to simplify signal gathering and processing. Fast and reliable characterization is achieved by comparison of certain properly selected characteristics of the scattered-light pattern with the corresponding theoretical values, which are readily derived from theoretical data and are stored in a look-up table. The data in this table were generated with a powerful boundary-element method, which can solve the direct scattering problem for virtually arbitrary shapes. A specially developed fast pattern-recognition technique makes possible the on-line characterization of axisymmetric particles. Successful results with red blood cells and bacteria are presented.

[Iris metastases. Apropos of 4 cases]. / Les métastases iriennes. A propos de 4 observations.

Metastatic tumors of the iris are rare. They most commonly arise from a primary breast or lung neoplasm and are associated with widespread carcinomatosis. They appear as white pink masses; anterior uveitis and hypertony can be seen. They are most often associated with short life expectancy. We report four cases and we show the interest of radiotherapy.

[Retinochoroidal involvement of type II membranoproliferative glomerulonephritis. An angiographic study with indocyanine green]. / Atteinte rétinochoroïdienne dans les glomérulonéphrites membrano-prolifératives de type II (GNMP II). Une étude angiographique au vert d'indocyanine.

PURPOSE: Type II measangiocapillary glomerulonephritis is related to dense deposits within the glomerular basal membrane and the basal membrane of the pigment epithelium (Bruch's membrane). Being a vasculitis, an angiographic study by indocyanine green (ICG) could possibly enlarge the semiologic features of this disease. METHODS: The indocyanine green angiographic changes in 3 patients with predialitic renal failure due to type II measangiocapillary glomerulonephritis (MCGN II) (dense deposit disease) are reported. A complete ophthalmologic examination, electroretinography, electro-oculography, fluorescein and indocyanine green angiography (ICG) were performed for each patient. RESULTS: Abnormal hyperfluorescent dots were seen on the same part of the fundus on both fluorescein and ICG angiography, though these locations were different for each of the three patients. These results seem to link the deposits to vascular changes within the choriocapillaris, which opposes them to drusen encountered in age related macular degeneration (ARMD). It appears that the choriocapillary lesions could be similar to the glomerular disease. CONCLUSION: Beyond the diagnostic challenges related to the nephrologic disease, it is known that subretinal neovascularization occurs in some cases of MCGN II, although the pathophysiologic mechanism of the deposits is probably not the same as in ARMD. Therefore, ICG angiography should be performed when MCGN II is first known, serving as an initial examination for further follow-up.

[Management of congenital microphthalmos and anophthalmos]. / Prise en charge des microphtalmies et anophtalmies congénitales.

PURPOSE: To better characterize congenital anophthalmos and microphthalmos in order to distinguish which patients need surgical treatment. MATERIALS AND METHODS: A retrospective study of 42 cases with congenital anophthalmos and microphthalmos over a 16 years period was performed. Seven anophthalmos, 20 microphthalmic globes with no associated colobomatous orbital cyst and 15 microphthalmic globes associated with colobomatous orbital cyst were observed. Complete history, pediatrical and ophthalmological examination, electrophysiological feature, oculo-cerebral imagery and karyotype on each of the patients were reviewed. RESULTS: Among all patients, lack of development of the lids was observed in 45% of cases. In our group of anophthalmos, 100% had micro-orbit. In our group of microphthalmic globes with no associated colobomatous orbital cyst, 30% had micro-orbit and in our group of microphthalmic globes associated with colobomatous orbital cyst, 6% had micro-orbit. 75% of patients had ocular anomalies and 39% had systemic anomalies, mostly on the face. Aetiology were found in 36% of cases. Visual evoked potentials and retinal electric feature were useful to better determine visual function. CONCLUSION: Expandable orbital prosthesis would appear to be the most effective therapy for certain cases of anophthalmos and microphthalmos with micro-orbit.

[Diabetes: why so many diabetic retinopathies diagnosed in the stage of complications?]. / Diabète: pourquoi toujours autant de rétinopathies diabétiques diagnostiquées au stade des complications?

PURPOSE: The aim of this study is to ascertain the reasons of the late diagnosis of severe diabetic retinopathies. METHODS: We analysed 30 diabetic patients seen at the initial examination with severe diabetic retinopathies, including risk factors of diabetes, quality of maintenance of a metabolic balance in blood sugar levels and examination of the fundus. RESULTS: Sixteen diabetic patients (53%) had no examination of the fundus from the onset of diabetes; 100% were over-weighted of more than 15%; 100% had no strict metabolic control of blood sugar levels; 90% had high blood pressure; 60% had familial diabetes. CONCLUSION: The prevention of late diagnosis of severe diabetic retinopathies must be based on the prevention of diabetes: examination and treatment of patients with high risk factors of diabetes. The prevention of diabetic retinopathy relies on the maintenance of a strict metabolic balance in blood sugar levels and required examination of the fundus every year.

Laser photocoagulation around the foci of toxoplasma retinochoroiditis: a descriptive statistical analysis of 35 patients with long-term follow-up.

Thirty-five patients with toxoplasma retinochoroiditis, receiving medical treatment and then treated with laser photocoagulation around the foci, were retrospectively evaluated for the risk of recurrence of the retinochoroiditis with a Kaplan-Meier representation. The recurrence rates with 95% symmetric confidence intervals were: at 1 year, 12.7 + or - 13%, at 2 years, 19.8 + or - 15%; at 3 years, 24.0 + or - 16%; at 4 years, 33.3 + or - 19%; at 5,6 and 7 years, 53.5 + or - 21%; at 8 and 9 years 66. 8 + or - 22%. With the data provided by our series, it is not possible to show the efficacy of laser photocoagulation as a prevention of recurrence in toxoplasma retinochoroiditis. Moreover, because of their heterogeneity, the recurrence rates from the literature cannot provide precise data for a comparison. Concerning the laser-induced thermal damage, the potential therapeutic mechanism of the laser procedure is discussed.

Biomechanical properties of hip cartilage in experimental animal models.

The material properties of normal adult articular cartilage were determined in the femoral head and acetabulum of baboons, dogs, and bovines, and were compared with those of normal human hip cartilage. In situ creep and recovery indentation experiments were performed using an automated creep indentation apparatus. To curvefit the entire creep curve, a numerical algorithm based on biphasic finite element methods and nonlinear optimization was developed. This effort represents the first successful use of 100% of the creep indentation curve to obtain the mechanical properties of normal articular cartilage. The results show that material properties of articular cartilage exhibit significant topographical variations in the femoral head and acetabulum, and between these two bone structures. Furthermore, significant differences exist in the mechanical properties of hip cartilage among the 4 species. Specifically, in all species the smallest aggregate modulus is found in the inferior aspect of the femoral head. Among all species, human hip cartilage is the stiffest in all test sites; bovine tissue is the softest. Human tissue has the smallest Poisson's ratio and permeability in all test sites. The aggregate modulus of human hip cartilage is closely resembled by that of baboon hip cartilage. Anatomically, canine and baboon hips exhibit similar characteristics to the human hip joint; the bovine hip joint is distinctly different. Based on this study's data, the baboon represents the most appropriate animal model of normal human hip articular cartilage.

Comparative clinical trial of AMO Vitrax and Healon use in extracapsular cataract extraction.

This randomized, single-masked, multicenter clinical trial, comprising 95 patients enrolled at five sites, evaluated the performance of AMO Vitrax and Healon viscoelastic materials during cataract surgery. Patients were examined preoperatively and at one day, four days, one month, and three months postoperatively. The following measurements were recorded and analyzed: percentage of endothelial cell loss from preoperative to three months postoperative; change in intraocular pressure (IOP) from preoperative to 24 hours postoperatively; postoperative corrected visual acuity; subjective assessment of ability of viscoelastic to create and maintain tissue space; intraocular transparency; ease of evacuation. Three months postoperatively, endothelial cell loss was 4.9% (+/- 8.3%) for the AMO Vitrax group and 6.3% (+/- 10.5%) for the Healon group. One day postoperatively, IOP decreased by 1.6 mm Hg and increased by +1.1 mm Hg, respectively. Postoperative visual acuities were similar between the two groups at three months. Subjective assessment of transparency was higher for Healon. Assessment of tissue space maintenance was similar between the two materials. Healon was rated as slightly easier to evacuate.

A biomechanical analysis of articular cartilage of the human elbow and a potential relationship to osteochondritis dissecans.

A cadaveric study of the articular surfaces of the radiocapitellar joint was undertaken to identify a biomechanical mechanism of osteochondritis dissecans of the humeral capitellum. The articulating radial head and capitellum of fresh anatomic specimens were dissected and tested for intrinsic mechanical properties. Significant differences exist in the mechanical properties and thickness of cartilage topographically in the capitellum and radial head, and between the two surfaces. The medial portion of the radial head is the softest of all radiocapitellar osteochondral segments tested. Comparing medial to lateral sites of the capitellum, there is a trend of decreased stiffness; lateral segments are softer than medial ones. The central section of the radial head is significantly stiffer than the lateral capitellum. There is no significant difference between the stiffness of the radial head sites and the medial capitellum. The disparity in the mechanical properties of the central radial head and lateral capitellum would increase strain in the lateral capitellum. During high-valgus stress activities such as throwing, this increased strain may be a factor in the initiation and localization of the dissecans lesion observed in osteochondritis dissecans of the elbow.

[Control of intensity of light coagulation by thermo-induced release of a fluorescent marker encapsulated in liposomes. In vivo/ex vivo preliminary study]. / Contrôle de l'intensité des photocoagulations par libération thermo-induite d'un marqueur fluorescent encapsulé dans des liposomes. Etude préliminaire in vivo/ex vivo.

PURPOSE: The aim of this in-vivo/ex vivo study was to assess the possible use of temperature sensitive liposomes in an established model such as the liver as a new approach to monitor the temperature induced by a laser. METHOD: Temperature sensitive liposomes (DSPC: DiStearoylPhophatidyl-Choline: critical temperature: 55 degrees C) loaded with carboxy-fluoresceine were prepared by the Bancham procedure. These liposomes (1 ml solution) were injected to adult male wistar rats. Two hours later, the liver was exposed and irradiated with a 100 W Nd: YAG laser (single pulse mode, pulses ranging from 100 to 260 ms, spot diameter: 4 mm). Simultaneously, the surface temperature was recorded with a infrared thermographic camera (Aga). The fluorescence emission was then measured with a fluorescent imaging system (Hamamatsu). RESULTS: The dye was released in response to laser energy. The amount of the drug release increased linearly with increasing temperature in the range 42 to 60 degrees C. The estimated latency of release seems more related to the heating pattern (i.e. to laser parameters) than to the liposomes. CONCLUSION: This preliminary study assesses the possible use of laser-induced release of liposome-encapsulated dye to monitor tissue temperature and then thermal damage.

[Sphenoidal aspergillosis in a seed-shop keeper]. / Aspergillose sphénoïdale chez une grainetière.

Human infections due to Aspergillosis Fungi are unusual and occur preferentially in defenseless patients. Nonetheless, our patient, a seed-shop owner, was not immuno-depressed and became infected by inhaling or chewing the seeds. Moreover, the aspergillosis was situated in the sphenoidal sinus, which is extremely unusual. In fact, the initial pseudo tumoral and misleading appearance justified a surgical biopsy which revealed a black "truffle" suggestive of aspergillosis and was confirmed by anatomo-pathology.

[Midline congenital fistula of the nose]. / Les fistules congénitales médianes du dos du nez.

Midline congenital fistulae of the nose requires early diagnosis to avoid infectious complications. This dermoid cyst of the nose may have intracranial extension and is the consequence of an anterior neural tube closure abnormality. The authors report 2 cases revealed by ophthalmic complications. Computed tomographic scan or magnetic resonance imaging provides precise information concerning the extent. Surgical treatment is always necessary.

[Gold salt deposits in the conjunctiva in rheumatoid arthritis after gold therapy. A systematic study of 15 biopsies]. / Dépôts de sels d'or conjonctivaux dans les polyarthrites rhumatoïdes traitées par chrysothérapie. Etude systématique de quinze biopsies.

Ocular abnormalities have long been recognized as a potential adverse effect of gold therapy in patients with rheumatoid arthritis. Clinical symptoms and ocular tissue lesions possibly related to use of gold therapy were routinely evaluated in eleven patients. There were few clinical manifestations: only one patient had typical accumulation of gold in the anterior crystalloid. In contrast, routine ultrastructural and microprobe studies of conjunctival biopsy specimens disclosed accumulation of gold salts in every case. Gold was visible as aurosomes in the conjunctival macrophages. Aurosomes were seen in patients treated for as little as one month, occurred even with low doses (0.3 g), and were still visible after several years. Duration of accumulation can be roughly estimated on the basis of the morphologic appearance of aurosomes which are lamellar after a few weeks of gold therapy and rod-shaped beyond one month.

High hyperopia with papillomacular fold.

We report a case of evolutive high hyperopia in a child aged 10 years. It is associated with organic amblyopia due to a large papillomacular retinal fold. Ultrasonography and CT scan helped to establish the diagnosis. This is probably a hereditary disease affecting the development of the posterior sclera.

Retinochoroidal coloboma and subretinal neovascularization.

Subretinal neovascularization associated with retinochoroidal coloboma is rare. To the authors' knowledge, only three cases have been reported. We report a new case of isolated subretinal neovascularization and coloboma in a 26-year-old woman without other causes of choroidal neovascularization. Only the disruption of the normal retinal anatomy could explain the development of this subretinal neovascularization.