Intra-trial mean 25(OH)D and PTH levels and risk of falling in older men and women in the Boston STOP IT trial

Context Supplementation with vitamin D has the potential to both reduce and increase risk of falling, and parathyroid hormone (PTH) may contribute to fall risk. Objective To assess the associations of intra-trial mean circulating levels of 25-hydroxyvitamin D [25(OH)D] and PTH on incident falls in healthy older adults. Design Observational within a clinical trial. Setting The Bone Metabolism Laboratory at the USDA Nutrition Center at Tufts University. Participants 410 men and women age 65 years and older who participated in the 3-year Boston STOP IT trial to determine the effect of supplementation with 700 IU of vitamin D3 plus calcium on incident falls (secondary endpoint). Intra-trial exposures of 25(OH)D and PTH were calculated as the mean of biannual measures up to and including the first fall. Main outcome measures: incidence of first fall Results Intra-trial mean 25(OH)D was significantly associated with risk of falling in a U-shaped pattern; the range associated with minimal risk of falling was approximately 20-40 ng/ml. PTH was not significantly associated with risk of falling. Conclusions The findings highlight the importance of maintaining the circulating 25(OH)D level between 20 and 40 ng/ml, the range that is also recommended for bone health. At PTH levels within the normal range, there was no detectible independent association of PTH with fall risk.

High Frequency Pressure Monitoring of the Re-Fracturing or Continuous Pumping Operations: Case Studies

The opportunity to refracture low-producing horizontal wells, which have been fractured few months before is getting more and more popular in the last few years. It provides the opportunity of restoring production without drilling new wells, which might be economically feasible especially in the oil and gas low price environment. However, the success rate of refracturing operations is usually low, mainly driven by the inability to properly stimulate the entire horizontal section. Consequently, many operators do not widely deploy this efficient technology. In contrast, completing a newly drilled well with plug and perf technology allows to individually treat from forty to sixty or even more individual compartments in the lateral section while refracturing attempts to retreat the entire lateral in the absence of any isolating device while trying to cover the entire lateral. There are at least two key factors affecting this operation. First is diversion technology: without efficient chemical diverters, which allow to temporarily block recently treated intervals and divert the stimulation fluid to different open sections of the well is extremely challenging. These diverters should normally be able to hold pressure differentials up to thousand psi or more. Attempting a treatment without this technology, aka a "blind frac" is not an option in many cases. The second factor is monitoring technology: The ability to recognize whether a zone has been successfully stimulated, to decide on the deployment of diverting technology or the further addition of stimulation fluid, to sponsor lateral coverage with minimal risk of premature screen out becomes of utmost importance for the successful outcome of hydraulic refracturing operations. In the absence of either of the aforementioned factors hydraulic refracturing may become inefficient and yield uneconomic success. This paper presents how the application of novel diverters, combined with proper hydraulic fracturing fluid selection, sound engineering design and more importantly hydraulic fracturing monitoring provide a new opportunity for the deployment of hydraulic refracturing to provide significant production increase and enhance recovery factor.

Vaccinating children against COVID-19: commentary and mathematical modelling

With the recent licensure of mRNA vaccines against COVID-19 in the 5-11 year old age group, the public health impact of a childhood immunization campaign is of interest. Using a mathematical epidemiological model, we project that childhood vaccination carries minimal risk and yields modest public health benefits. These include large relative reductions in child morbidity and mortality, although the absolute reduction is small because these events are rare. Furthermore, the model predicts altruistic absolute reductions in adult cases, hospitalizations, and mortality. However, vaccinating children to benefit adults should be considered from an ethical as well as a public health perspective. From a global health perspective, an additional ethical consideration is the justice of giving priority to children in high-income settings at low risk of severe disease while vaccines have not been made available to vulnerable adults in low-income settings.

Transtumoral endoprothesis in surgery of colorectal cancer, complicated with colonic obstruction: advantages and disadvantages. A review of the literature

A multifactorial analysis of the literature data on the treatment of acute tumor colonic obstruction using minimally invasive endoscopic surgical technology was carried out. On the basis of the analysis of special publications, the effectiveness of stenting of the large intestine, as a minimally invasive endoscopic method of decompression, is presented. Indications and contraindications for colorectal stenting, advantages and disadvantages, possibilities and prospects of endoscopic decompression of the colon are described in detail. It is postulated that stenting, used in acute tumor obstruction of the colon as a «bridge to surgery», being a worthy alternative to classical colostomy, allows an effective antegrade decompression of the colon and prepares the patient to surgical treatment with the performance of oncological justified primary radical and one-stage restorative operations in more optimal conditions with minimal risk. It is shown that in the late stages of the malignant process and in the presence of neresect-leucorrhoea colorectal cancer, as well as in the presence of absolute contraindications to a radical surgeon Colon stenting can serve as the final treatment for inoperable patients.

What Do Participants Think of Our Research Practices? An Examination of Behavioral Psychology Participants’ Preferences

What research practices should be considered acceptable? Historically, scientists have set the standards for what constitutes acceptable research practices. However, there is value in considering non-scientists’ perspectives, including research participants’. 1,873 participants from MTurk and university subject pools were surveyed after their participation in one of eight minimal-risk studies. We asked participants how they would feel if common research practices were applied to their data: p-hacking/cherry-picking results, selective reporting of studies, Hypothesizing After Results are Known (HARKing), committing fraud, conducting direct replications, sharing data, sharing methods, and open access publishing. An overwhelming majority of psychology research participants think questionable research practices (e.g., p-hacking, HARKing) are unacceptable (68.3--81.3%), and were supportive of practices to increase transparency and replicability (71.4--80.1%). A surprising number of participants expressed positive or neutral views toward scientific fraud, raising concerns about the quality of our data. We grapple with this concern and interpret our results in light of the limitations of our study. Despite ambiguity in our results, we argue that there is evidence (from our study and others’) that researchers may be violating participants’ expectations and should be transparent with participants about how their data will be used.

Dynamic portfolio rebalancing through reinforcement learning

Portfolio managements in financial markets involve risk management strategies and opportunistic responses to individual trading behaviours. Optimal portfolios constructed aim to have a minimal risk with highest accompanying investment returns, regardless of market conditions. This paper focuses on providing an alternative view in maximising portfolio returns using Reinforcement Learning (RL) by considering dynamic risks appropriate to market conditions through dynamic portfolio rebalancing. The proposed algorithm is able to improve portfolio management by introducing the dynamic rebalancing of portfolios with vigorous risk through an RL agent. This is done while accounting for market conditions, asset diversifications, risk and returns in the global financial market. Studies have been performed in this paper to explore four types of methods with variations in fully portfolio rebalancing and gradual portfolio rebalancing, which combine with and without the use of the Long Short-Term Memory (LSTM) model to predict stock prices for adjusting the technical indicator centring. Performances of the four methods have been evaluated and compared using three constructed financial portfolios, including one portfolio with global market index assets with different risk levels, and two portfolios with uncorrelated stock assets from different sectors and risk levels. Observed from the experiment results, the proposed RL agent for gradual portfolio rebalancing with the LSTM model on price prediction outperforms the other three methods, as well as returns of individual assets in these three portfolios. The improvements of the returns using the RL agent for gradual rebalancing with prediction model are achieved at about 27.9–93.4% over those of the full rebalancing without prediction model. It has demonstrated the ability to dynamically adjust portfolio compositions according to the market trends, risks and returns of the global indices and stock assets.

Simple technique of distal leg perfusion during heart transplant in patients with preoperative veno-arterial extracorporeal membrane oxygenation support

Direct heart transplant from veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support is challenging. Continuation of postoperative VA-ECMO support may be required in the setting of primary graft dysfunction or severe vasoplegia. We describe a simple technique to perfuse the ipsilateral leg of an arterial ECMO cannula during heart transplant while the ECMO circuit is turned off but maintaining the arterial cannula and distal perfusion catheter in place. This technique minimizes the number of intraoperative procedures with a minimal risk of leg ischemia, and provides a smooth transition to postoperative VA-ECMO support if necessary.

Corneal graft survival analysis after penetrating keratoplasty in a retrospective cohort study

Purpose. To assess the results of penetrating keratoplasty and identify the risk factors for the graft disease (GD) development. Material and methods. Data of 582 patients after corneal transplantation performed in the period since 2011 to 2019 for keratoconus (41%), as well for corneal leucorrhoea and dystrophies (59%), aggravated by concomitant pathology, the so-called high-risk keratoplasty (HRK) were analyzed in a retrospective cohort study. We estimated the functional results and incidence of GD. The calculation of the t-criterion; cross-tabulation method; Kaplan–Meier survival analysis and multivariate analysis were applied. Results. As a result of penetrating keratoplasty, the BCVA (best corrected visual acuity) in patients with keratoconus increased by 20%; in patients with HRK – by 8%. In the general group the graft survival rate was 72%, while the 8-year successful graft engraftment in patients with keratoconus comprised 91%, with HRK – 60%. A significant relationship of the GD development with preoperative diagnosis and rekeratoplasty was determined. The risk of GD incidence was minimal in patients under 30 years of age and maximum in patients aged from 50 to 70 years. Survival rates for corneal transplants were better in men than in women. Conclusion. Penetrating keratoplasty in patients with keratoconus provides a good functional result with a minimal risk of GD development. With penetrating keratoplasty in high-risk patients, the effectiveness of surgical interventions is significantly lower (by ~30%). Key words: keratoconus, penetrating keratoplasty, corneal transplantation, survival analysis

Development and Optimization of Floating Microspheres in Amethopterin

Due to the complexity of gastric emptying, as well as its considerable variability, the in vivo efficacy of drug delivery devices cannot be predicted. When it pertains to drugs with an absorption window in the upper small intestine, a controlled drug delivery system with a longer residence period in the stomach may be of considerable practical significance. Recent developments have shown that floating microspheres are particularly well suited for mixing sustained and delayed releases to achieve a variety of release models with a minimal risk of dumping. The aim of present investigation is to develop and analyze the floating microspheres of amethopterin, which after oral administration could increase the gastric residence time and enhance the bioavailability of the drug by sustained release and minimize the dose dependent side effects as well as improves patient compliance. Floating microspheres of ethyl cellulose, Polyvinyl alcohol and polyvinyl pyrrolidone-K90 were formulated by emulsification solvent evaporation technique. The various parameters of prepared microspheres were studied for SEM, flow properties, buoyancy, yield, percent drug loading, in vitro dissolution studies, stability in different pH and FTIR studies. Microspheres prepared with different concentrations of polymers were spherical in shape with smooth surface. The size of microspheres was in range of 256.02 µm and 362.84 µm. Good drug entrapment and buoyancy were observed for formulation F2. The in vitro drug release after 6h was found to be in range from 58.15% to 96.28%. It was established that the newly created floating microspheres of Amethopterin provide an appropriate and practical solution for the sustained release of medication over a longer period of time, resulting in increased oral bioavailability, effectiveness, as well as better patient compliance.

Acceptable Risks in Pediatric Research: Views of the US Public

BACKGROUND AND OBJECTIVES: Critics argue that it is unethical to expose children to research risks for the benefit of others, whereas many regulations permit “net-risk” pediatric research but only when the risks are minimal. In the present survey, we assessed whether the US public agrees with these views and whether the US public’s views regarding the acceptability of net-risk pediatric research are influenced by its social value. METHODS: A 15-minute survey of a nationally representative sample of US adults. Participants were randomly assigned to 1 of 4 hypothetical scenarios involving procedures that pose increasing levels of risk. To assess whether respondents’ views on the acceptability of the risks is influenced by the social value of the research, in each of the 4 scenarios we described the respective procedure being used in 3 studies with increasing levels of social value. RESULTS: A total 1658 of the 2508 individuals who were sent the survey link participated (response rate = 66.1%). Approximately 91% approved of a research blood draw in minors, and ∼69% approved of a research bone marrow biopsy. The proportion who indicated that the respective procedure was acceptable increased as the study’s social value increased. This effect was significantly stronger for studies which pose greater risks compared with studies with lower risks (P < .001). CONCLUSIONS: The vast majority of the US public supports net-risk pediatric research that poses minimal risk, and a majority supports net-risk pediatric research that poses somewhat greater risks, provided it has high social value. These findings offer important information for assessing when it is acceptable to conduct net-risk pediatric research.