A Literature Review of the Effects of Air Pollution on COVID-19 Health Outcomes Worldwide: Statistical Challenges and Data Visualization.

Several peer-reviewed papers and reviews have examined the relationship between exposure to air pollution and COVID-19 spread and severity. However, many of the existing reviews on this topic do not extensively present the statistical challenges associated with this field, do not provide comprehensive guidelines for future researchers, and review only the results of a relatively small number of papers. We reviewed 139 papers, 127 of which reported a statistically significant positive association between air pollution and adverse COVID-19 health outcomes. Here, we summarize the evidence, describe the statistical challenges, and make recommendations for future research. To summarize the 139 papers with data from geographical locations around the world, we also present anopen-source data visualization tool that summarizes these studies and allows the research community to contribute evidence as new research papers are published.

Diagnostic value of 3 T MR spectroscopy, diffusion-weighted MRI, and apparent diffusion coefficient value for distinguishing benign from malignant myometrial tumours.

AIM: To further verify the effectiveness of diffusion-weighted (DWI) magnetic resonance imaging (MRI) and 1H magnetic resonance spectroscopy (MRS) using a 3 T MRI system to differentiate benign leiomyomas from uterine sarcoma; to investigate the benefit of adding MRS to the apparent diffusion coefficient (ADC) for improving the specificity of the benign/malignant classification. MATERIALS AND METHODS: The dataset included 21 uterine sarcoma from 14 patients and 84 benign leiomyomas from 51 patients. T1-and T2-weighted images as well as DWI were obtained using a 3-T MRI system. Approximately 60% of patients also underwent MRS. The chi-square test was used to compare the percentage of malignant lesions that showed choline peaks, lipid peaks, and restricted diffusion to the corresponding percentage of benign masses. Using the area under a receiver operating characteristic (AUC) curve, the efficacy of different parameters for distinguishing uterine sarcomas from leiomyomas was measured. RESULTS: The visual assessment of DWI images showed that 100% of malignant lesions exhibited restricted diffusion while the corresponding figure for benign leiomyomas was only 5%. The mean ADC of malignant tumours differed significantly from that of benign ones (p<0.001). The percentage of malignant lesions for which choline and lipid peaks were present was significantly higher than that of benign lesions. By combining the ADC and MRS findings, an accuracy of 98.3 (95.1-100) was achieved. CONCLUSIONS: The findings suggested that a combination of DWI and MRS could be useful in the preoperative assessment of uterine masses to differentiate benign leiomyomas from leiomyosarcoma.

128-bit spectral processing of sub-picosecond optical pulses in a standard SOI CMOS process.

Optical short pulse processors enable several systems including optical code division multiple access networks, optical secure communications, and optical pulse shapers. For instance, compact and low cost integrated solutions for optical short pulse en/de-coders with large code length and capable of processing large optical bandwidth may enable realization of Tbps communication networks. Here, we report an integrated 128-bit short pulse processor capable of signal processing on large amount of optical bandwidth, demonstrated ≈ 25 nm, using sub-ps optical short pulse signal. The chip fabricated in a commercial foundry SOI CMOS process and includes more than 500 distinct optical components and over 150,000 distinct electrical components.

Trends in outpatient cataract surgery in the Islamic Republic of Iran, 2006-2010.

This study aimed to determine the trends in outpatient cataract surgery and its determinants in the Islamic Republic of Iran between 2006 and 2010. In this cross-sectional study, 106 cataract surgery centres were selected in all provinces by multistage randomized cluster sampling. The number of centres in each province was determined from the number of cataract operations and the number of patient charts examined in each centre was proportionate to the number of cataract operations in that centre. The prevalence of outpatient surgery increased from 46.0% (95% CI, 35.3-56.8) in 2006 to 51.4% (95% CI, 40.2-62.7) in 2010 (P = 0.549). Patients stayed in hospital for more than one night after 10.5% (95% CI, 6.9-14.1) of operations. Use of phacoemulsification and topical anaesthesia increased the prevalence of outpatient surgery and decreased intraoperative complications. Although outpatient cataract surgery increased by 11.7%, use of methods such as phacoemulsification is not widespread, and more attention should be paid to the barriers to outpatient cataract surgery in the Islamic Republic of Iran.

Reconfigurable optofluidic switch for generation of optical pulse width modulation based on tunable reflective interface.

We present a numerical method for generation of optical pulse width modulation (PWM) based on tunable reflective interface by using a microfluidic droplet. We demonstrate a single layer, planar, optofluidic PWM switch that is driven by excited alternating microbubbles. The main parameters of generation of this PWM such as frequency and speed of switching can be controlled by the mass flow rates of input fluids, and the shape of plug or droplet. Advantages of this design are the reconfigurability in design and the easy control of the switching parameters. The validation of the proposed design is carried out by employing the finite element method (FEM) for the mechanical simulation and the finite-difference time-domain (FDTD) for the optical simulation.

Contributions of public and private sectors to the Iranian cataract surgery output.

This study determined trends in the contributions of the public and private sectors to the cataract surgery output in the Islamic Republic of Iran. Data about cataract surgeries performed at surgical centres throughout the nation were extracted from patient charts for a 5-year period from 2006 to 2010. Of the total 516 273 surgeries performed in 2010, more were done in public sector centres (61.7%) than private ones (38.3%). The total number of surgeries increased by 59.1% between 2006 and 2010. Analysis of the relative contributions of the public and private sectors showed a 41.0% increase in surgeries in public centres and 100.5% in private centres over the 5-year period. Thus the rate of growth of cataract surgery in the private sector was 2.7 times greater than that in the public sector. Despite a smaller contribution to the total number of cataract surgeries, the private sector has experienced a substantial rate of growth.

Why do the [PhSiO(1.5)](8,10,12) cages self-brominate primarily in the ortho position? Modeling reveals a strong cage influence on the mechanism.

(PhSiO1.5)8,10,12 cages are bulky, electron withdrawing like CF3; yet self-brominate (60 °C), favoring ortho substitution: PhT8 (≈85%), PhT10 (≈75%) and PhT12 (60%). First-principles calculations suggest bromination initiates when Br2 is "trapped" via H-bonding to ortho-H's, followed by polarization via strong interactions with cage faces, possibly cage LUMOs.

Generation of coherent 19- and 38-nm radiation at a free-electron laser directly seeded at 38 nm.

Initiating the gain process in a free-electron laser (FEL) from an external highly coherent source of radiation is a promising way to improve the pulse properties such as temporal coherence and synchronization performance in time-resolved pump-probe experiments at FEL facilities, but this so-called "seeding" suffers from the lack of adequate sources at short wavelengths. We report on the first successful seeding at a wavelength as short as 38.2 nm, resulting in GW-level, coherent FEL radiation pulses at this wavelength as well as significant second harmonic emission at 19.1 nm. The external seed pulses are about 1 order of magnitude shorter compared to previous experiments allowing an ultimate time resolution for the investigation of dynamic processes enabling breakthroughs in ultrafast science with FELs. The seeding pulse is the 21st harmonic of an 800-nm, 15-fs (rms) laser pulse generated in an argon medium. Methods for finding the overlap of seed pulses with electron bunches in spatial, longitudinal, and spectral dimensions are discussed and results are presented. The experiment was conducted at FLASH, the FEL user facility at DESY in Hamburg, Germany.

Vitamin D deficiency and diabetic retinopathy risk.

PURPOSE: Vitamin D deficiency may play an important role in the development and progression of diabetic retinopathy. The present study aimed to assess the relationship between vitamin D deficiency and the likelihood of diabetic retinopathy. METHODS: This nested case-control study was conducted on all type II diabetic patients among the participants of the third phase of the Shahroud eye cohort study. Overall, 278 patients aged 50 to 74 years, 101 in the case group (diabetic retinopathy) and 178 in the control group (diabetic without retinopathy), were assessed. Serum levels of vitamin D on admission were measured for all participants by a radio immunoassay (RIA) technique. RESULTS: The overall prevalence of vitamin D deficiency (defined as a vitamin D level of less than or equal to 20mg/dL) was 30.7%. Comparison of the serum level of vitamin D across the three groups - without retinopathy, with non-proliferative retinopathy, and with proliferative retinopathy - showed a significantly lower level of this marker in the latter group (P=0.036). Reducing vitamin D to less than or equal to 20ng/mL increased the odds of proliferative retinopathy by 6.25 times (P value: 0.027). CONCLUSION: Vitamin D deficiency is a potential risk factor for diabetes-related proliferative retinopathy.

Lymph Node Metastases Detection Using Gd2O3@PCD as Novel Multifunctional Contrast Imaging Agent in Metabolic Magnetic Resonance Molecular Imaging.

Axillary lymph node detection is crucial to staging and prognosis of the lymph node metastatic spread in breast cancer. Currently, lymphoscintigraphy and blue dye, as the conventional methods to localize sentinel lymph nodes (SLNs), are invasive and can only be performed during surgery. This study has had a novel hybrid gadolinium oxide nanoparticle coating with Cyclodextrin-based polyester as a high-relaxivity T1 magnetic resonance molecular imaging (MRMI) contrast agent (CA). Twelve female BALB/c mice were randomly divided into three groups of four mice; each group was injected with 4T1 cells to obtain metastasis lymph nodes and diagnosed by using the 3D T1W (VIBE) MRI (Siemens 3T, Prisma). The synthesized Gd2O3@PCD nanoparticles with a suitable particle size range of 20-40 nm have had much higher longitudinal relaxivity (r 1) for Gd2O3@PCD and Gd-DOTA (Dotarem) with the values of 3.98 mM-1·s-1 ± 0.003 and 2.71 mM-1·s-1 ± 0.005, respectively. Identical MR images in coronal views were subsequently obtained to create time-intensity curves of the right axillary lymph nodes and to measure the contrast ratio (CR). The peak CR and qualitative assessment of axillary lymph nodes at five-time points were evaluated. After subcutaneous injection, the contrast ratio of axillary lymph node and tumor in mice exhibited CR peak of Gd2O3@PCD and Dotarem with the values of 2.21 ± 0.06 and 0.40 ± 0.004 for lymph node and 2.54 ± 0.04 and 1.21 ± 0.007 for the tumor, respectively. Furthermore, the lumbar-aortic lymph node is weakly visible in the original coronal image. In conclusion, the use of Gd2O3@PCD nanoparticles as novel MRMI CAs enables high resolution for the detection of lymph node metastasis in mice with the potential capability for breast cancer diagnostic imaging.

Does Gadolinium Deposition Lead to Metabolite Alteration in the Dentate Nucleus? An MRS Study in Patients with MS.

BACKGROUND AND PURPOSE: Repeat contrast-enhanced MR imaging exposes patients with relapsing-remitting MS to frequent administration of gadolinium-based contrast agents. We aimed to investigate the potential metabolite and neurochemical alterations of visible gadolinium deposition on unenhanced T1WI in the dentate nucleus using MRS. MATERIALS AND METHODS: This prospective study was conducted in a referral university hospital from January 2020 to July 2021. The inclusion criteria for case and control groups were as follows: 1) case: patients with relapsing-remitting MS, visible gadolinium deposition in the dentate nucleus (ribbon sign), >5 contrast-enhanced MR images obtained; 2) control 1: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, >5 contrast-enhanced MR images obtained; 3) control 2: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, <5 contrast-enhanced-MR images obtained; and 4) control 3: adult healthy individuals, with no contrast-enhanced MR imaging. Dentate nucleus and pontine single-voxel 12 × 12 × 12 MRS were analyzed using short TEs. RESULTS: Forty participants (10 per group; 27 [67.5%] female; mean age, 35.6 [SD, 9.6] years) were enrolled. We did not detect any significant alteration in the levels of NAA and choline between the studied groups. The mean concentrations of mIns were 2.7 (SD, 0.73) (case), 1.5 (SD, 0.8) (control 1), 2.4 (SD, 1.2) (control 2), and 1.7 (SD, 1.2) (control 3) (P = .04). The mean concentration of Cr and mIns (P = .04) and the relative metabolic concentration (dentate nucleus/pons) of lipid 1.3/Cr (P = .04) were significantly higher in the case-group than in healthy individuals (controls 1-3). Further analyses compared the case group with cumulative control 1 and 2 groups and showed a significant increase in lactate (P = .02), lactate/Cr (P = .04), and Cr (dentate nucleus/pons) (P = .03) in the case group. CONCLUSIONS: Although elevated concentrations of Cr, lactate, mIns, and lipid in the dentate nucleus of the case group indicate a metabolic disturbance, NAA and choline levels were normal, implying no definite neuronal damage.

Seroprevalence of Toxoplasma gondii in unmarried women in Qazvin, Islamic Republic of Iran.

In a cross-sectional study, we evaluated the seroprevalence of Toxoplasma gondii among 400 women referred to Qazvin community health centre laboratory for pre-marriage examinations. Indirect immunofluorescent antibody test was used to detect IgG anti-toxoplasma. Titres > or = 1: 20 were considered positive. The overall seropositivity was 34%. Mean age was significantly higher in seropositive women (P < 0.05). Seropositivity was highest among unemployed women (38.3%) and lowest among students (22.6%), and was significantly higher in women with less than high-school education (P < 0.05). With two-thirds of these unmarried women seronegative, they represent a high-risk group in pregnancy. Such women need to be educated to prevent congenital toxoplasmosis.

Novel FMRI-Compatible wrist robotic device for brain activation assessment during rehabilitation exercise.

Magnetic Resonance Imaging (MRI) can be applied to study the effects of rehabilitation strategies for neuroscience research. An MRI-wrist robot is designed and used as a clinical tool to examine the process of the brain plasticity changes. In this robot, the patient actuation is accomplished with two standard air cylinders, located inside the MRI chamber with two degrees of freedom (flexion-extension and ulna-radial deviation) with pneumatic air transmission, consisting of simple mechanism converting rotary motion to linear independently. A pilot study of brain image aiming at revealing more effective therapeutic strategies carried out to confirm the technical aspects of the development and validation. In a healthy subject, both wrist movement of robot and subject demonstrated brain activity in the contralateral primary somatosensory cortex. Because the robot does not move during the patient's body, a stand was designed to allow the wrist robot and patient to fit comfortably within the MRI machine. While all the parts of the robot were carefully selected with strict MRI compatibility requirements, the robot was tested by presenting some pilot imaging data with null effects on the image quality, as well. Finally, the possible further development of the robot has been introduced for a rehabilitation assessment.

Outbreak of severe disseminated aspergillosis in a flock of ostrich (Struthio camelus).

This study was undertaken to describe clinical, mycological and histopathological findings in black neck ostriches affected with severe aspergillosis in a flock including 80 birds, near Tehran, Iran. The signs included anorexia, depression, notable weight loss, diarrhoea, severe respiratory distress and death. Grossly, the lungs showed numerous white to yellow caseous nodules and the walls of the thoracic and abdominal air sacs were thickened with inflammatory exudates containing cellular debris, necrotic masses and green mold colonies. Multiple nodules were observed in the liver, spleen and gastrointestinal tract as well. Histopathologically, there were conidial heads and fungal hyphae in the air sacs and multifocal necrotic and granulomatous lesions with septated and dichotomously branched hyphae in various tissues, which were stained with haematoxylin and eosin and Grocott's methenamine silver nitrate. Aspergillus fumigatus was isolated in various tissues taken from affected ostriches.

Differentiation of Edematous, Tumoral and Normal Areas of Brain Using Diffusion Tensor and Neurite Orientation Dispersion and Density Imaging.

BACKGROUND: Presurigical planning for glioma tumor resection and radiotherapy treatment require proper delineation of tumoral and peritumoral areas of brain. Diffusion tensor imaging (DTI) is the most common mathematical model applied for diffusion weighted MRI data. Neurite orientation dispersion and density imaging (NODDI) is another mathematical model for DWI data modeling. OBJECTIVE: We studied whether extracted parameters of DTI, and NODDI models can be used to differentiate between edematous, tumoral, and normal areas in brain white matter (WM). MATERIAL AND METHODS: 12 patients with peritumoral edema underwent 3T multi-shell diffusion imaging with b-values of 1000 and 2000 smm-2 in 30 and 64 gradient directions, respectively. We fitted DTI and NODDI to data in manually drawn regions of interest and used their derived parameters to characterize edematous, tumoral and normal brain areas. RESULTS: We found that DTI parameters fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) all significantly differentiated edematous from contralateral normal brain WM (p<0.005). However, only FA was found to distinguish between edematous WM fibers and tumor invaded fibers (p = 0.001). Among NODDI parameters, the intracellular volume fraction (ficvf) had the best distinguishing power with (p = 0.001) compared with the isotropic volume fraction (fiso), the orientation dispersion index (odi), and the concentration parameter of Watson distribution (κ), while comparing fibers inside normal, tumoral, and edematous areas. CONCLUSION: The combination of two diffusion based methods, i.e. DTI and NODDI parameters can distinguish and characterize WM fibers involved in edematus, tumoral, and normal brain areas with reasonable confidence. Further studies will be required to improve the detectability of WM fibers inside the solid tumor if they hypothetically exist in tumoral parenchyma.

Determination and Diversity of Bovine Coccidia in Zabol, East of Iran.

The present study was designed to investigate the prevalence of Eimeria spp. in Zabol, east of Iran. The samples were examined microscopically for the presence of oocysts from February 2015 to December 2016. Out of 196 cattle, 124 (63.26%) were identified to be positive for Eimeria species. Eight species of Eimeria were found as follows: E. bovis (42.54%), E. zuernii (38.67%), E. subspherica (5.52%), E. brasiliensis (4.97%), E. ellipsoidalis (4.41%), E. cylindrical (1.65%), E. pellita (1.65%), and E. wyomingensis (0.55%). Multiple infections with two or three species were identified in 56 (45.16%) and 2 (1.61%) cases, respectively. The infection rate was observed to be higher in calves (75%) as compared to adult cattle (59.02%). The prevalence of Eimeria was greater in female cattle (67.94%). The highest prevalence and mean number of oocysts were observed in winter (69%) and autumn (209.09), respectively. All the faecal samples had an oocysts per gram of feces (OPG) less than 1000. The prevalence of infection and mean OPG were directly correlated with rainfall and relative humidity and inversely correlated with temperature. Considering the high prevalence of bovine coccidiosis in Zabol, increasing awareness of farmers and veterinarians regarding the economic importance of bovine coccidiosis should be regarded as an important factor in preventing and controlling the infection.

Intraoperative optical coherence tomography to evaluate the effect of the eyelid speculum on corneal pachymetry during accelerated corneal cross-linking (9 mW/cm2).

PurposeTo investigate intraoperative anterior segment optical coherence tomography (AS-OCT) to compare pachymetry changes between two methods (group 1: speculum-on, group 2: speculum-off during riboflavin instillation stage) during corneal cross-linking /CXL) (9 mW/cm2 for 10 min) in keratoconic patients.MethodsIn this interventional case series, 11 eyes (11 patients) in group 1 and 14 eyes (14 patients) in group 2 were enrolled. Pachymetry measurements by spectral domain OCT was performed at baseline, after epithelial removal, after 30 min of imbibition with riboflavin, and after UV irradiation. Repeated measures analysis of variance was used to compare the trend of changes in different stages of the procedure within and between two groups.ResultsThe corneal thinnest pachymerty (CTP) at baseline, after epithelial removal, 30 min of riboflavin instillation, and irradiation was 469.8±26.5, 438.0±27.1, 354.3±28.4, 367.1±31.8 microns in group 1 and 463.2±25.1, 438.0±27.1, 421.6±54.0, 386.9±34.0 microns in group 2, respectively. Group 1 showed a significantly greater decrease in the corneal pachymetry (P<0.001) during riboflavin instillation, while in group 2 a greater decrease in CTP was observed during the UV irradiation phase (P=0.002).ConclusionsUsing the intraoperative OCT, the speculum-off group had a more stable corneal pachymetry during riboflavin instillation time. Despite this, the effect was not lasting throughout the procedure; significant changes were noted in the corneal pachymetry at the end of operation in both groups; further highlighting the limitations imposed by corneal stromal shrinkage using isotonic dextran containing riboflavin solution for CXL.

The prevalence of visual impairment and blindness in underserved rural areas: a crucial issue for future.

PurposeTo determine the prevalence of visual impairment and blindness in underserved Iranian villages and to identify the most common cause of visual impairment and blindness.Patients and methodsMultistage cluster sampling was used to select the participants who were then invited to undergo complete examinations. Optometric examinations including visual acuity, and refraction were performed for all individuals. Ophthalmic examinations included slit-lamp biomicroscopy and ophthalmoscopy. Visual impairment was determined according to the definitions of the WHO and presenting vision.ResultsOf 3851 selected individuals, 3314 (86.5%) participated in the study. After using the exclusion criteria, the present report was prepared based on the data of 3095 participants. The mean age of the participants was 37.6±20.7 years (3-93 years). The prevalence of visual impairment and blindness was 6.43% (95% confidence interval (CI): 3.71-9.14) and 1.18% (95% CI: 0.56-1.79), respectively. The prevalence of visual impairment varied from 0.75% in participants aged less than 5 years to 38.36% in individuals above the age of 70 years. Uncorrected refractive errors and cataract were the first and second leading causes of visual impairment; moreover, cataract and refractive errors were responsible for 35.90 and 20.51% of the cases of blindness, respectively.ConclusionThe prevalence of visual impairment was markedly high in this study. Lack of access to health services was the main reason for the high prevalence of visual impairment in this study. Cataract and refractive errors are responsible for 80% of visual impairments which can be due to poverty in underserved villages.

Uncorrected refractive errors and spectacle utilisation rate in Tehran: the unmet need.

AIM: To determine the prevalence of the met and unmet need for spectacles and their associated factors in the population of Tehran. METHODS: 6497 Tehran citizens were enrolled through random cluster sampling and were invited to a clinic for an interview and ophthalmic examination. 4354 (70.3%) participated in the survey, and refraction measurement results of 4353 people aged 5 years and over are presented. The unmet need for spectacles was defined as the proportion of people who did not use spectacles despite a correctable visual acuity of worse than 20/40 in the better eye. RESULTS: The need for spectacles in the studied population, standardised for age and sex, was 14.1% (95% confidence interval (CI), 12.8% to 15.4%). This need was met with appropriate spectacles in 416 people (9.3% of the total sample), while it was unmet in 230 people, representing 4.8% of the total sample population (95% CI, 4.1% to 5.4%). The spectacle coverage rate (met need/(met need + unmet need)) was 66.0%. Multivariate logistic regression showed that variables of age, education, and type of refractive error were associated with lack of spectacle correction. There was an increase in the unmet need with older age, lesser education, and myopia. CONCLUSION: This survey determined the met and unmet need for spectacles in a Tehran population. It also identified high risk groups with uncorrected refractive errors to guide intervention programmes for the society. While the study showed the unmet need for spectacles and its determinants, more extensive studies towards the causes of unmet need are recommended.