31 research outputs found

    Several non-linear models in estimating air-overpressure resulting from mine blasting

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    This research presents several non-linear models including empirical, artificial neural network (ANN), fuzzy system and adaptive neuro-fuzzy inference system (ANFIS) to estimate air-overpressure (AOp) resulting from mine blasting. For this purpose, Miduk copper mine, Iran was investigated and results of 77 blasting works were recorded to be utilized for AOp prediction. In the modeling procedure of this study, results of distance from the blast-face and maximum charge per delay were considered as predictors. After constructing the non-linear models, several performance prediction indices, i.e. root mean squared error (RMSE), variance account for (VAF), and coefficient of determination (R2) and total ranking method are examined to choose the best predictive models and evaluation of the obtained results. It is obtained that the ANFIS model is superior to other utilized techniques in terms of R2, RMSE, VAF and ranking herein. As an example, RMSE values of 5.628, 3.937, 3.619 and 2.329 were obtained for testing datasets of empirical, ANN, fuzzy and ANFIS models, respectively, which indicate higher performance capacity of the ANFIS technique to estimate AOp compared to other implemented methods

    Determination of diazinon concentration by Gas Chromatography - Mass Spectrometry in underground drinking water resources located near the rice fields, before and after the pesticide spraying

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    Widespread and unsupervised use of pesticides in the rice fields of northern Iran has greatly increased the concern about their presence in drinking water resources. This study aimed to determine the effect of spraying of rice fields on the concentration of diazinon in rural underground drinking water resources with depth and water table of about 120 and 30 m respectively. Sampling was performed at regular intervals, before the first and after the last spraying. Diazinon extraction was carried out by USEPA liquid�liquid extraction method and the concentration of diazinon was measured by GC / Mass Spectrometry. No diazinon was observed in any of water resources before spraying, while the average concentration of diazinon after spraying was 0.005 ± 0.007 µg/l. Also there was a significant difference in diazinon concentration between water resources after spraying rice fields. There was a reverse significant correlation between the diazinon concentration and longitudinal distance from water resources to rice farms. Moreover, there was a significant direct correlation between the diazinon concentration in post-spraying samples and water turbidity. In general, spraying rice fields can cause diazinon to enter underground water resources near farms and it can be present in water resources for at least one month after the last spraying. © 2021 Elsevier B.V

    Biometric Variations in High Myopia Associated with Different Underlying Ocular and Genetic Conditions

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    Purpose: To report different biometric measurements in high myopia associated with different underlying ocular and genetic conditions. Design: Retrospective study. Subjects: Patients with high myopia. Methods: We searched the Stanford Research Repository tool to identify patients with the diagnosis of high myopia who were seen by a single provider at Byers Eye Institute at Stanford from January 2019 to March 2022. We performed a chart review and included eyes that had high myopia and ocular biometric measurements at any time point after January 2019. We divided our cohort into 5 different groups: (1) isolated high myopia (IHM) (control group); (2) retinopathy of prematurity (ROP); (3) familial exudative vitreoretinopathy; (4) Marfan syndrome; and (5) Stickler syndrome. Main Outcome Measures: Biometric measurements. Results: A total of 246 patients (432 eyes) were included as follows: 202 patients (359 eyes) in the IHM group, 17 patients (27 eyes) in the ROP group, 7 patients (12 eyes) in the familial exudative vitreoretinopathy group, 8 patients (14 eyes) in the Marfan group, and 12 patients (20 eyes) in the Stickler group. The ROP group showed significantly shorter axial lengths, shallower anterior chambers, and thicker lenses compared with the IHM group. The Marfan group showed significantly flatter corneas and thicker lenses compared with the IHM group. The Stickler group showed significantly longer axial lengths compared with the IHM group. Conclusions: High myopia is associated with variable biometric measurements according to underlying ocular or genetic conditions. Retinopathy of prematurity-associated high myopia is primarily lenticular, while Stickler syndrome-associated high myopia is axial. Marfan syndrome-associated high myopia is derived from both axial and lenticular mechanisms

    Neurosarcoidosis, Coccidioidomycosis, or Both!

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    Amir Akhavanrezayat,1 Wataru Matsumiya,1,2 Prapatsorn Ongpalakorn,1 Hashem H Ghoraba,1 Chris Or,1 Hassan Khojasteh Jafari,1 Gunay Uludag Kirimli,1 Cigdem Yasar,1 Ngoc Trong Tuong Than,1 Irmak Karaca,1 Moosa Zaidi,1 Azadeh Mobasserian,1 Negin Yavari,1 Vahid Bazojoo,1 Yong Un Shin,1 Albert John Bromeo,1 Quan Dong Nguyen1 1Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA; 2Department of Surgery, Division of Ophthalmology, Kobe University Graduate School of Medicine, Kobe, JapanCorrespondence: Quan Dong Nguyen, Spencer Center for Vision Research, Byers Eye Institute at Stanford University, 2452 Watson Court, Suite 200, Palo Alto, CA, 94303, USA, Tel +1 650 723 9386, Email [email protected]: To report a case of neurosarcoidosis (NS) who was initially diagnosed as Coccidioidomycosis immitis (CI) infection.Observations: A 57-year-old diabetic man presented with sudden painless diminution of vision, metamorphopsia, and color vision deficits in the left eye (OS) for one month. His vision was 20/20 in the right eye (OD) and 20/40 OS. Ophthalmic examination revealed left relative afferent pupillary defect, blurred optic nerve margin, creamy chorioretinal infiltration around the optic disc, and mild macular edema. OD examination was non-revealing. Chest CT scan with contrast showed calcified mediastinal lymph nodes, but biopsy of the lymph nodes was normal. Brain and orbit MRI demonstrated soft tissue abnormality with enhancement in left orbital apex with involvement of the extraocular muscles. CSF culture was negative, but complement fixation had positive titer of 1:2 for CI. The patient was diagnosed with CI meningitis, and antifungal therapy was initiated. Slight visual and symptomatic improvement was observed, which was not completely satisfactory. Biopsy of extraocular orbital muscle five months later revealed non-caseating granulomatous inflammation, leading to initiation of prednisone trial therapy. Nine months later, the patient was referred to a tertiary center owing to persistence of optic disc edema OS. PET CT was consistent with a diagnosis of sarcoidosis. Antifungal treatment was discontinued, and oral prednisone with methotrexate was initiated. Subsequently, methotrexate was replaced by infliximab to further manage ocular inflammation and neurologic symptoms which was effective. Vision was 20/20 OD and 20/30 OS at the most recent visit.Conclusion and Importance: Signs and symptoms of neurosarcoidosis and coccidioidomycosis can be similar and deceiving. The index case underscores importance of considering appropriate differential diagnoses in patients with similar symptoms and signs who may respond to preliminary designated treatment but not to the optimal extent. Considering such possibility could assist clinicians in managing the patients timely and efficiently.Keywords: neurosarcoidosis, coccidioidomycosis, sarcoidosis, ocular involvemen
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