On Identifying and Mitigating Bias in the Estimation of the COVID-19 Case Fatality Rate

The relative case fatality rates (CFRs) between groups and countries are key measures of relative risk that guide policy decisions regarding scarce medical resource allocation during the ongoing COVID-19 pandemic. In the middle of an active outbreak when surveillance data is the primary source of information, estimating these quantities involves compensating for competing biases in time series of deaths, cases, and recoveries. These include time- and severity- dependent reporting of cases as well as time lags in observed patient outcomes. In the context of COVID-19 CFR estimation, we survey such biases and their potential significance. Further, we analyze theoretically the effect of certain biases, like preferential reporting of fatal cases, on naive estimators of CFR. We provide a partially corrected estimator of these naive estimates that accounts for time lag and imperfect reporting of deaths and recoveries. We show that collection of randomized data by testing the contacts of infectious individuals regardless of the presence of symptoms would mitigate bias by limiting the covariance between diagnosis and death. Our analysis is supplemented by theoretical and numerical results and a simple and fast open-source codebase at https://github.com/aangelopoulos/cfr-covid-19 .Comment: Harvard Data Science Review (2020) article available at https://hdsr.mitpress.mit.edu/pub/y9vc2u3

Wireless Intraocular Pressure Sensing Using Microfabricated Minimally Invasive Flexible-Coiled LC Sensor Implant

This paper presents an implant-based wireless pressure sensing paradigm for long-range continuous intraocular pressure (IOP) monitoring of glaucoma patients. An implantable parylene-based pressure sensor has been developed, featuring an electrical LC-tank resonant circuit for passive wireless sensing without power consumption on the implanted site. The sensor is microfabricated with the use of parylene C (poly-chlorop- xylylene) to create a flexible coil substrate that can be folded for smaller physical form factor so as to achieve minimally invasive implantation, while stretched back without damage for enhanced inductive sensor–reader coil coupling so as to achieve strong sensing signal. A data-processed external readout method has also been developed to support pressure measurements. By incorporating the LC sensor and the readout method, wireless pressure sensing with 1-mmHg resolution in longer than 2-cm distance is successfully demonstrated. Other than extensive on-bench characterization, device testing through six-month chronic in vivo and acute ex vivo animal studies has verified the feasibility and efficacy of the sensor implant in the surgical aspect, including robust fixation and long-term biocompatibility in the intraocular environment. With meeting specifications of practical wireless pressure sensing and further reader development, this sensing methodology is promising for continuous, convenient, direct, and faithful IOP monitoring

Fibular collateral ligament reconstruction of knee using titanium button: a new fixation technique and an outcome of 35 cases

Background: The fibular collateral ligament (FCL) is an important stabilizer of the lateral side of the knee through the whole range of motion. Likewise, it resists external rotation near full extension. Many techniques has been described in the literature for fixation of graft to the fibula like interference screws, making loop around the fibula head but nothing has been said about Titanium button fixation at Fibula end. In our series graft has been fixed at Fibula end using Titanium button. In this article we described our new graft fixation technique.Methods: We included 35 patients all were solider of Indian army and navy who got their knee injured during duties, sport, training and accident, were operated with new technique of graft fixation at Fibula end.Results: As far as my search in the present literature while writing our present study the graft fixation at Fibular end using Titanium button has not yet described by any author. This fixation is robust and results were promising. Out of 35 cases only 02 patients developed knee stiffness and none were has lateral knee opening (Varus stress test was negative). All patients were available for follow up for 18 months.Conclusions: Based on our new technique of the graft fixation at Fibular end using Titanium button we can conclude that this technique is simple and fixation is robust with promising results

Fracture neck of femur treated with hemiarthroplasty and cannulated cancellous screw fixation: a comparative study

Background: Intracapsular fracture neck of femur has always presented great challenges to every Orthopaedic surgeons and it is remain a mystery whether to fix or to replace the fracture in the elderly. The aim of the study was to analyze the functional outcome of two widely used and accepted modalities of treatment in the age group 57-75 years, in Garden’s type I and II fractures, namely (a) cannulated cancellous screw fixation(internal fixation) and (b) modular bipolar prosthetic replacement of the femoral head (hemiarthroplasty).Methods: The total 110 patients were including in the study from age groups 57-75 (mean age 66). The Garden classification of fracture neck of femur was used to evaluate the displacement of femoral neck fractures. Only grade 1 and 2 was included in the study. 55 patients were included in each group A and B. Osteosynthesis (fracture fixation) was carried out by closed reduction and insertion of cannulated cancellous screw and in other group hemiarthroplasty was done.Results: In group A 55 patient with fracture neck of femur was treated by osteosynthesis i.e. fixation using 02 or 03 cannulated cancellous screw and in group B, 55 patients with fracture neck of femur was treated by modular bipolar replacement hemiarthroplasty. In Group A out of 55, 41 patients union was achieved between 08 to 14 months (mean 11.5 month), 09 patients developed non-union even after 16 months and 05 patients develop collapse of head with AVN with shortening at end of 02 year, however in Group B out of 55 patients 51 patients started walking after 2nd postoperative days, 02 patients developed infection, and 02 patients developed posterior dislocation.Conclusions: The fracture fixation may be tempting for fracture neck femur in age group 57-75 especially of Garden Type I but internal fixation put risk of non-union and AVN and second surgery may be required after few months or years  if patients survive. Based on results in our study we therefore can conclude that in Garden Type I and II femur neck fractures in the patients between 57-75 years of age, hemiarthroplasty is the better modality of treatment

Management and functional outcome of Galeazzi fracture dislocation: a single centre retrospective study

Background:Galeazzi fracture dislocation is an unstable fracture dislocation of forearm that includes fracture of distal third or fourth shaft of radius with dislocation of distal radioulnar joint. The aim of the study was to analyse the management and functional outcome of Galeazzi fracture dislocation managed with fixation of radius fracture and distal radioulnar joint stabilisation with two Kirschner wires.Methods:Thirty one patients with Galeazzi fracture dislocation were managed with plate fixation for radius fracture and distal radioulnar joint stabilisation with 2 Kirschner wires. They were clinically and radiographically assessed for functional outcome as well as union, distal radioulnar joint stability and any arthrosis of the wrist joint.Results:Functional outcome was assessed based on disability of shoulder, arm, and hand index. 94% of the patients in our series had good to fair outcome with 6% having poor outcome.Conclusions:All Galeazzi fracture dislocation should be managed with plate fixation for radius fracture and Kirschner wire stabilisation of distal radioulnar joint followed by splinting for 6 weeks for best functional outcome

Halotolerant Plant Growth Promoting Bacilli from Sundarban Mangrove Mitigate the Effects of Salinity Stress on Pearl Millet (Pennisetum glaucum L.) Growth

Pearl millet (Pennisetum glaucum L.) is one of the major crops in dry and saline areas across the globe. During salinity stress, plants encounter significant changes in their physio and biochemical activities, leading to decreased growth and yield. Bacillus species are used as biofertilizers and biopesticides for pearl millet and other crops to promote growth and yield. The use of Bacillus in saline soils has been beneficial to combat the negative effect of salinity on plant growth and yield. In this context, the present study emphasizes the use of two Bacillus species, i.e. Bacillus megaterium JR-12 and B. pumilus GN-5, which helped in alleviating the impact of salinity stress on the growth activities in salt-stressed pearl millet. Pearl millet seeds were treated with two strains, B. megaterium JR-12 and B.pumilus GN-5, individually and in combination under 50, 100 and 150 mM of sodium chloride stress. The treated plants showed higher plant height, biomass accumulation, and photosynthetic apparatus than the non-treated plants. Additionally, the treated plants showed increased osmoprotectant levels under salinity stress compared to control plants. The antioxidant enzyme content was improved post-inoculation, indicating the efficient stress-alleviating potential of both strains of Bacillus species. Moreover, inoculation of these microbes significantly increased plant growth attributes in plants treated with a combination of Bp-GN-5 + Bm-JR-12 and the reduction rates of plant growth were found to be alleviated to 9.12%, 20.30% and 33%, respectively. Overall, the results of the present study suggested that these microbes could have a higher potential to improve the productivity of pearl millet under salinity stress

Evaluation of the role of posterior malleolus fixation in trimalleolar ankle fractures: a prospective study

Background: Trimalleolar ankle fractures are relatively rare and complex ankle injuries, the prognosis of which is worse than bimalleolar fracture. The three malleoli are bony restraints of the ankle and all three are fractured in trimalleolar fractures. Hence, there is disruption of the weight bearing portion of the tibial plafond along with talus dislocation/subluxation. Management of such fractures is challenging and confounded by the dilemma of posterior malleolus fixation. Aim: The aim of the present study was to evaluate the radiological and clinical outcome of fixation of large (>25%) posterior malleolus fragment in trimalleolar fractures.Methods: 25 patients underwent fixation of the three malleoli and evaluated prospectively. Different methods for fixation from plating to lag screws were used for posterior malleolus.Results: 92% of patients in our series had excellent to good clinical outcome. Radiologically, there was anatomical reduction of the ankle joint and none of the patient had postoperative talus subluxation or arthrosis.Conclusions: Our study shows that there is consistent and reproducible clinical advantage of fixing the posterior malleolus in trimalleolar ankle fractures.

Implantable micromechanical parylene-based pressure sensors for unpowered intraocular pressure sensing

This paper presents the first implantable, unpowered, parylene-based microelectromechanical system (MEMS) pressure sensor for intraocular pressure (IOP) sensing. From in situ mechanical deformation of the compliant spiral-tube structures, this sensor registers pressure variations without electrical or powered signal transduction of any kind. Micromachined high-aspect-ratio polymeric hollow tubes with different geometric layouts are implemented to obtain high-sensitivity pressure responses. An integrated device packaging method has been developed toward enabling minimally invasive suture-less needle-based implantation of the device. Both in vitro and ex vivo device characterizations have successfully demonstrated mmHg resolution of the pressure responses. In vivo animal experiments have also been conducted to verify the biocompatibility and functionality of the implant fixation method inside the eye. Using the proposed implantation scheme, the pressure response of the implant can be directly observed from outside the eye under visible light, with the goal of realizing convenient, direct and faithful IOP monitoring in glaucoma patients