Evaluate underdiagnosis and overdiagnosis bias of deep learning model on primary open-angle glaucoma diagnosis in under-served populations

In the United States, primary open-angle glaucoma (POAG) is the leading cause of blindness, especially among African American and Hispanic individuals. Deep learning has been widely used to detect POAG using fundus images as its performance is comparable to or even surpasses diagnosis by clinicians. However, human bias in clinical diagnosis may be reflected and amplified in the widely-used deep learning models, thus impacting their performance. Biases may cause (1) underdiagnosis, increasing the risks of delayed or inadequate treatment, and (2) overdiagnosis, which may increase individuals' stress, fear, well-being, and unnecessary/costly treatment. In this study, we examined the underdiagnosis and overdiagnosis when applying deep learning in POAG detection based on the Ocular Hypertension Treatment Study (OHTS) from 22 centers across 16 states in the United States. Our results show that the widely-used deep learning model can underdiagnose or overdiagnose under-served populations. The most underdiagnosed group is female younger (< 60 yrs) group, and the most overdiagnosed group is Black older (≥ 60 yrs) group. Biased diagnosis through traditional deep learning methods may delay disease detection, treatment and create burdens among under-served populations, thereby, raising ethical concerns about using deep learning models in ophthalmology clinics.

Developing Population Health Surveillance Using mHealth in Low-Resource Settings: Qualitative Assessment and Pilot Evaluation

BACKGROUND

Population surveillance data are essential for understanding population needs and evaluating health programs. Governmental and nongovernmental organizations in western Myanmar did not previous have means for conducting robust, electronic population health surveillance.

OBJECTIVE

This study involved developing mobile health (mHealth)-based population health surveillance in a rural, low-resource setting with minimal cellular infrastructure in western Myanmar. This was an early formative study in which our goal was to establish the initial feasibility of conducting mHealth population health surveillance, optimizing procedures, and building capacity for future work.

METHODS

We used an iterative design process to develop mHealth-based population health surveillance focused on general demographics (eg, total census, age category, sex, births, and deaths). Interviews were conducted with international consultants (nurse midwives) and local clinicians (nurses and physicians) in Myanmar. Our analytic approach was informed by the Systems Engineering Initiative for Patient Safety work systems model to capture the multilevel user needs for developing health interventions, which was used to create a prototype data collection tool. The prototype was then pilot-tested in 33 villages to establish an initial proof of concept.

RESULTS

We conducted 7 interviews with 5 participants who provided feedback regarding the domains of the work system, including environmental, organizational, sociocultural, technological, informational, and task- and people-based considerations, for adapting an mHealth tool. Environmental considerations included managing limited electricity and internet service. Organizational needs involved developing agreements to work within existing government infrastructure as well as leveraging the communal nature of societies to describe the importance of surveillance data collection and gain buy-in. Linguistic diversity and lack of experience with technology were both cited as people- and technology-based aspects to inform prototype design. The use of mobile tools was also viewed as a means to improve the quality of the data collected and as a feasible option for working in settings with limited internet access. Following the prototype design based on the findings of initial interviews, the mHealth tool was piloted in 33 villages, allowing our team to collect census data from 11,945 people for an initial proof of concept. We also detected areas of potentially missing data, which will need to be further investigated and mitigated in future studies.

CONCLUSIONS

Previous studies have not focused heavily on the early stages of developing population health surveillance capacity in low- and middle-income countries. Findings related to key design considerations using a work systems lens may be informative to others developing technology-based solutions in extremely low-resource settings. Future work will involve collecting additional health-related data and further evaluating the quality of the data collected. Our team established an initial proof of concept for using an mHealth tool to collect census-related information in a low-resource, extremely rural, and low-literacy environment.

Probing the topological surface states in superconducting Sn4Au single crystal: a magneto transport study

Materials exhibiting bulk superconductivity along with magnetoresistance (MR) in their normal state have emerged as suitable candidates for topological superconductivity. In this article, we report a flux free method to synthesize single crystal of topological superconductor candidate Sn₄Au. The phase purity and single crystalline nature are confirmed through various characterizations viz. x-ray diffraction, field emission scanning electron microscopy, selected area electron diffraction, and transmission electron microscopy. Chemical states of the constituent element viz. Sn and Au are analysed through x-ray photoelectron spectroscopy. Superconductivity in synthesized Sn₄Au single crystal is evident formρ-Tplot, for which the critical field (H_c) is determined throughρ-Hplot at 2 K i.e. just below critical temperatureT_c. A positive MR is observed inρ-Hmeasurements at different temperatures aboveT_c, viz. at 3 K, 5 K, 10 K and 20 K. Further, the magnetoconductivity (MC) is analysed by using Hikami-Larkin-Nagaoka formalism, which signifies the presence of weak antilocalization (WAL) effect in Sn₄Au. Angle dependent magneto-transport measurement has been performed to detect the origin of observed WAL effect in Sn₄Au single crystal. Normalized MC vsHcosθplot shows presence of topological surface states in the studied system. It is evident that Sn₄Au is a 2.6 K topological superconductor.

Detailed magneto heat capacity analysis of SnAs topological superconductor

In this article, we report magneto heat capacity analysis of superconducting SnAs. Magneto heat capacity analysis of superconductors is an important tool to determine bulk superconductivity as well as the pairing mechanism of Cooper pairs. SnAs crystal is characterized through x-ray diffraction and x-ray photoelectron spectroscopy. Magneto transport measurements of studied SnAs superconductor evidenced presence of superconductivity at around 4 K, which persists up to an applied field of 250 Oe. The bulk nature of superconductivity is determined through AC susceptibility (χ) along with the heat capacity measurements. Magneto heat capacity measurements show SnAs to be a fully gapped s wave superconductor. This finding is well supported by calculated physical parameters likeα(3.36),λ_e-ph(0.70) and ΔC_el/γT_c(1.41). Calculation of residual Sommerfeld coefficient (γ_res) at different fields, confirms node-less superconductivity in SnAs.

Green Approach: ''A Forwarding Step for Curing Leishmaniasis-A Neglected Tropical Disease''

The present review focuses on a dreaded vector-mediated leishmaniasis, with the existing therapeutic approaches including a variety of drugs along with their limitations, the treatment with natural compounds, and different types of metal/metal oxide nanoparticles (NPs). As evidenced, various metallic NPs, comprising silver, silver oxide, gold, zinc oxide, titanium, lead oxide, etc., played a curative role to treat leishmaniasis, are also presented. Keeping in view the advance success of vaccines against the prevalent dreaded diseases in the past and the present scenario, efforts are also being made to develop vaccines based on these NP formulations.

A critical study of the manuscripts of Paryaya Muktavali available at Orissa

Though the Nidana book of Madhavakara has been very popular among Ayurvedic fraternity his other deeds on Dravyaguna, Cikitsa etc. could not come to lime light due to lack of sufficient number of manuscripts for comparison and editing. One such text is Paryaya Muktavali, manuscripts of which are plentily available in the State of Orissa. This modified text redacted by Hari Charana Sena, is a bright example of scribal error and missing of verses which occur during repeated scribe in palm leaf manuscript. This is a lexicon of drugs, which is prime necessity of Dravyaguna and Rasaśastra. Publication of such text will be an addition to the treasure of Ayurvedic texts.

Detachment of Particles from Surfaces: An AFM Study

We have measured interactions between hydrophilic and hydrophobic surfaces in an aqueous medium at various pH and ionic strengths as well as in some organic solvents using atomic force microscopy and analyzed them in terms of particle adhesion and detachment from surfaces. In hydrophilic systems the forces observed were found to be well described by DLVO theory at large separation distances. Very long range hydrophobic forces were not observed in hydrophilic-hydrophobic systems. Nevertheless, the jump into contact was found to occur at distances greater that those predicted by just van der Waals attraction. The interaction between two hydrophobic surfaces was dominated by the long-range attraction due to hydrophobic forces. This interaction was found to be sensitive to the type of substrate as well as to the pH and electrolyte concentration. Measured pull-off forces showed poor reproducibility. However, average values showed clear trends and were used to estimate interfacial energies or work of adhesion for all systems studied by means of the Derjaguin approximation. These values were compared to those calculated by the surface tension component theory using the acid-base approach. Good qualitative agreement was obtained, giving support for the usefulness of this approach in estimating interfacial energies between surfaces in liquid media. A comparison of the measured adhesion force with hydrodynamic detachment experiments showed good qualitative agreement. Copyright 2001 Academic Press.

Selective imaging of biofilms in porous media by NMR relaxation

Nuclear magnetic resonance imaging (NMRI) techniques were employed to identify and selectively image biological films (biofilm) growing in aqueous systems. Biofilms are shown to affect both the longitudinal (T1) and transverse (T2) NMR relaxation time values of proximal water hydrogens. Results are shown for biofilm growth experiments performed in a transparent parallel-plate reactor. A comparison of biofilm distributions by both NMR and optical imaging yielded general agreement for both an open-flow system and an idealized porous system (the reactor without and with packed glass beads, respectively). The selective imaging of biofilm by relaxation NMRI is dependent upon the resolution of relaxation times for the fluid phases, dynamic range, and signal-to-noise ratio. For open-flow systems, the use of a rapid and quantitative T2-sorted NMRI technique was preferred. For porous systems where T2 values are generally more similar, a T1-weighted technique was preferred.

Evaluating the interaction of bacteria with biomaterials using atomic force microscopy

Bacterial infection of biomaterials represents one of the most important reasons for the failure of transdermal or implanted medical devices. The first and least understood step in biomaterial-associated infections is the initial interaction between bacteria and a surface. This initial interaction can be either attractive or repulsive depending on the physiochemical nature of the biological and synthetic surfaces, as well as the properties of the interstitial fluid. We have shown that atomic force microscopy (AFM) can be employed as an exquisitely sensitive and versatile tool for quantifying the interaction between bacteria and surfaces in physiological solutions. The forces of interaction between an AFM cantilever tip and a uniform lawn of bacteria immobilized on glass were determined. By comparing the interactions of cantilever tips with lawns of isogenic E. coli strains carrying genetic lesions that alter their cell surface composition, it was possible to evaluate the effect of macromolecules such as lipopolysaccharide and capsular polysaccharide on the adhesion process. Mutations that result in the synthesis of truncated lipopolysaccharide or in the overproduction of the negatively charged capsular polysaccharide colanic acid render the interaction of the bacteria with the AFM tip unfavorable due to increased electrostatic repulsion. Furthermore, AFM could be used to evaluate the adhesion of bacteria onto commercially relevant biomaterials. In one approach, micron-size polystyrene beads were attached to AFM tips which were then used to measure forces. Unfortunately, this approach is limited by the meager number of materials manufactured as beads of a size suitable for AFM measurements. As an alternative approach, AFM cantilever tips were coated with a confluent layer of bacteria and used to probe planar surfaces. In this configuration, AFM could be employed to measure the force of interaction between virtually any bacterium and surface of interest.

Molecular determinants of bacterial adhesion monitored by atomic force microscopy

Bacterial adhesion and the subsequent formation of biofilm are major concerns in biotechnology and medicine. The initial step in bacterial adhesion is the interaction of cells with a surface, a process governed by long-range forces, primarily van der Waals and electrostatic interactions. The precise manner in which the force of interaction is affected by cell surface components and by the physiochemical properties of materials is not well understood. Here, we show that atomic force microscopy can be used to analyze the initial events in bacterial adhesion with unprecedented resolution. Interactions between the cantilever tip and confluent monolayers of isogenic strains of Escherichia coli mutants exhibiting subtle differences in cell surface composition were measured. It was shown that the adhesion force is affected by the length of core lipopolysaccharide molecules on the E. coli cell surface and by the production of the capsular polysaccharide, colanic acid. Furthermore, by modifying the atomic force microscope tip we developed a method for determining whether bacteria are attracted or repelled by virtually any biomaterial of interest. This information will be critical for the design of materials that are resistant to bacterial adhesion.

Structural and immunological characterization of a biosurfactant produced by Bacillus licheniformis JF-2

Bacillus licheniformis JF-2 produces a very active biosurfactant under both aerobic and anaerobic conditions. We purified the surface-active compound to homogeneity by reverse-phase C18 high-performance liquid chromatography and showed that it is a lipopeptide with a molecular weight of 1,035. Amino acid analysis, fast atom mass and infrared spectroscopy, and, finally, 1H, 13C, and two-dimensional nuclear magnetic resonance demonstrated that the biosurfactant consists of a heterogeneous C15 fatty acid tail linked to a peptide moiety very similar to that of surfactin, a lipopeptide produced by Bacillus subtilis. Polyclonal antibodies were raised against surfactin and shown to exhibit identical reactivity towards purified JF-2 lipopeptide in competition enzyme-linked immunosorbent assays, thus providing further evidence for the structural similarity of these two compounds. Under optimal conditions, the B. licheniformis JF-2 biosurfactant exhibits a critical micelle concentration of 10 mg/liter and reduces the interfacial tension against decane to 6 x 10(-3) dyne/cm, which is one of the lowest interfacial tensions ever reported for a microbial surfactant.

Herbert screw: results of a single-centre trial

We report the results of a single-centre trial of the Herbert screw in the treatment of acute fractures, fracture-dislocations and non-unions of the carpal scaphoid. In the trial, 22 patients were studied with a maximum follow-up of 2.5 years. Of the patients, 84 per cent had minimal or no pain, and 94 per cent were happy with their result or significantly improved. There was an average loss of 34 per cent of radial deviation of the wrist and of 10 per cent in cylinder grip strength. On radiographic examination, 86 per cent achieved satisfactory union. However, only 73 per cent of type D2 fractures united. Overall, the subjective and objective clinical results achieved were more satisfactory than the radiographic results would suggest.

Surface–Active Compounds from Microorganisms

Microbial surfactants are a structurally diverse group of compounds consisting of hydrophilic and hydrophobic domains and which partition preferentially at interfaces. Biosurfactants are of increasing interest commercially as substitutes for synthetic surfactants particularly for environmental applications. This article discusses recent progress in the genetic and biochemical analysis of biosurfactant synthesis as well as the current status of fermentation technologies.

Immediate effect of tobacco chewing in the form of 'paan' on certain cardio-respiratory parameters

Immediate effect of tobacco in the form of chewing was evaluated in 40 healthy males (mean age 26.27 yrs.) not habituated to tobacco, who were given paan containing 200 mg of tobacco to chew (group T). Heart rate (HR), blood pressure (BP), forced vital capacity (FVC), FEV1 and peak expiratory flow rate (PEFR) were measured twice for each subject, once before chewing and again immediately after completion of chewing. Another 24 age and sex matched controls (group C) were given paan without tobacco to chew and cardiorespiratory parameters were recorded as for group T subjects. Electrocardiography was recorded in 10 group T and 10 group C subjects. Effect of tobacco chewing was also evaluated in 10 habitual tobacco chewers. Results showed statistically significant increments in HR and BP as well as a decline in T wave amplitude in ECG following tobacco chewing (group T subjects). The changes in HR and BP lasted for 15-30 mins, as observed in 10 of group T subjects. The FVC, FEV1 and PEFR showed marginal, though non-significant, increments after tobacco chewing. No significant difference in the cardiorespiratory responses to tobacco chewing could be seen between habitual and nonhabitual (group T) tobacco chewers. The changes in cardiovascular and respiratory parameters following paan (without tobacco) chewing in the control subjects were negligible and nonsignificant.

FEF200-1200, FEF25-75% and FEF75-85% in non-smokers of either sex and in male smokers residing at an altitude of 2150 M above MSL in Himachal Pradesh

Forced expiratory flow (FEF) rates were determined for 170 (130 males and 40 females) healthy adults of Himachal Pradesh in the age group of 19-26 years for males and 19-22 years for females. The subjects had been staying at an altitude of 2150 M above mean sea level (MSL) for at least three years prior to the conduct of the study. FEF200-1200, FEF25-75% and FEF75-85% were found to be high as compared to those reported from most other parts of the country. The results were found comparable with those reported from certain populations in U.S.A. Further, the flow rates of the non-smoker males were compared with those of the male smokers. FEF75-85% in smokers was significantly less than that of non-smokers, whereas the differences in FEF200-1200 and FEF25-75% were found to be nonsignificant.

Efficacy of metronidazole in dracunculiasis. A clinical trial

In a clinical trial of metronidazole for dracunculiasis (75 cases), the drug was effective in giving symptomatic relief but had no preventive or vermicidal action. It was well tolerated. No difference was observed in the results of two dose schedules (200 mg or 400 mg three times daily for 10 days).

Endoscopic measurement of pancreatic juice secretory flow rates and pancreatic secretory pressures after secretin administration in human controls and in patients with acute relapsing pancreatitis, chronic pancreatitis, and pancreatic cancer

Secretory flow rates were measured inside the main pancreatic duct during endoscopic retrograde cholangiopancreatography (ERCP) in patients with acute relapsing pancreatitis, chronic pancreatitis, and pancreatic cancer and in controls after intravenous administration of secretin. Peak secretory flow rates in these groups were 5.04 +/- 1.74, 0.71 +/-1.28, 0.60 +/- 1.37, and 4.13 +/- 0.88 ml/min, respectively. Peak secretory pressures were also measured intraductally in patients with acute relapsing pancreatitis and pancreatic cancer and in controls and were 402 +/- 69, 75 +/- 161, and 403 +/- 99 mm pancreatic juice, respectively. Peak secretory flow rates and pressures measured in controls during constant administration of secretin were similar to those measured when secretin was administered as a bolus.

Pancreatic hypersecretion in liver disease

Abnormally large duodenal aspirates have been reported in a large percentage of patients with cirrhosis of the liver. The source of this fluid has been variously ascribed to the liver and/or pancreas. The present study was undertaken to clarify its source. Eleven patients with cirrhosis of the liver and one with cholestatic hepatitis underwent an intraductal secretin test during endoscopic cannulation of the pancreatic duct. Six patients with cirrhosis had pancreatic hypersecretion ranging from 7.8 to 26.0 ml/min, while three patients demonstrated low secretory flow rates. Bile flow was negligible or nonexistent in ten patients, while in two others, larger but unmeasurable amounts of bile secretion were present. This study conclusively demonstrates that pancreatic hypersecretion may occur in patients with cirrhosis during secretin stimulation. Impaired metabolism of secretin or the associated pancreatic hypersecretion of early pancreatitis may be responsible for this finding.

Splenic-gonadal fusion

Various aspects of splenic-gonadal fusion are discussed and 1 case of the continuous type is reported. A plea is made to include this condition in the differential diagnosis of scrotal masses, particularly those on the left side.

Primary actinomycosis of the abdominal wall

A rare case of primary actinomycosis of the abdominal wall presenting as a tumour is described. The patient responded to penicillin therapy well. A brief account of the literature is included.