The impact of dentists' availability in delivering dental care in Florida Elementary Schools.

OBJECTIVE: This study evaluates the dentists' availability to deliver preventive dental care to children in schools and the impact of school-based programs on access. METHODS: The study population included Florida elementary-school children, differentiated by dental insurance (Medicaid, CHIP, private, or none). We considered the implementation of school-based programs using optimization modeling to (re)allocate the dentists' caseload to schools to meet demand for preventive care under resource constraints. We considered multiple settings for school-based program implementation: (i) school prioritization; and (ii) dentists' participation in public insurance. Statistical inference was used to identify communities to improve access and reduce disparities. RESULTS: School-based programs reduced unmet demand (3%-12%), being more efficient if prioritizing schools in communities targeted to improve access. The access improvement varied by insurance status and geography. Uninsured urban children benefited most from school-based programs, with 15%-75% unmet need reduction. The percentage of urban communities targeted to improve access decreased by 12% against no-school program. Such percentage remained large for suburban (15%-100%) and rural (50%-100%) communities. Disparity in access for public-insured vs. private-insured children persisted under school-based programs (32%-84% identified communities). CONCLUSION: School-based programs improve dental care access; the improvement was however different by insurance status, with uninsured children benefiting the most. Accounting to the dentists' availability in prioritizing schools resulted in effective resource allocation to school-based programs. Access disparities between public and private-insured children did not improve; school-based programs shifted resources from public-insured to uninsured. School-based programs are effective in addressing access barriers to those children experiencing them most.

Parallel Subgradient Algorithm with Block Dual Decomposition for Large-scale Optimization.

This paper studies computational approaches for solving large-scale optimization problems using a Lagrangian dual reformulation, solved by parallel sub-gradient methods. Since there are many possible reformulations for a given problem, an important question is: Which reformulation leads to the fastest solution time? One approach is to detect a block diagonal structure in the constraint matrix, and reformulate the problem by dualizing the constraints outside of the blocks; the approach is defined herein as block dual decomposition. Main advantage of such a reformulation is that the Lagrangian relaxation has a block diagonal constraint matrix, thus decomposable into smaller sub-problems that can solved in parallel. We show that the block decomposition can critically affect convergence rate of the sub-gradient method. We propose various decomposition methods that use domain knowledge or apply algorithms using knowledge about the structure in the constraint matrix or the dependence in the decision variables, towards reducing the computational effort to solve large-scale optimization problems. In particular, we introduce a block decomposition approach that reduces the number of dualized constraints by utilizing a community detection algorithm. We present empirical experiments on an extensive set of problem instances including a real application. We illustrate that if the number of the dualized constraints in the decomposition increases, the computational effort within each iteration of the sub-gradient method decreases while the number of iterations required for convergence increases. The key message is that it is crucial to employ prior knowledge about the structure of the problem when solving large scale optimization problems using dual decomposition.

Mechanical colon cleansing device in patients with chronic constipation: An experimental study.

Background: Constipation is one of the most common gastrointestinal discomforts that affects various age groups in humans. Different mechanical cleansing devices have been introduced yet. However, they are very expensive and not available in our country. Methods: This was a pilot experimental trial. Fifteen patients with eligible ROME III criteria and at least two years of chronic constipation and resistant to medical therapy entered the study. Wexner and Longo's scores were checked before and after using the "Roodeshur" device. Data entered SPSS 16 and analyzed using T-test. A p value below 0.05 was considered as a statistically significant difference. Results: Five patients were female and 10 males. The mean age of patients was 53.56±18.34 years. There was a significant difference regarding intestinal movement before and after using the device (p˂0.001). Wexner's score decreased after the intervention with a significant difference (p˂0.001). Conclusion: Our mechanical cleansing device (Roodeshur) was effective and safe for patients with resistance constipation. No complication occurred. Due to its low cost and easy access in our country, it can be recommended for other patients as well. However, more studies with a larger sample size are recommended.

Abdominal Surgery in Patients With COVID-19: Detection of SARS-CoV-2 in Abdominal and Adipose Tissues.

Multiple tissue samples were obtained during emergent abdominal surgery in 4 patients with coronavirus disease 2019 (COVID-19) to examine for tissue involvement by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first patient underwent a laparoscopic cholecystectomy for gallbladder empyema and died from severe respiratory failure. The second patient with Crohn disease underwent emergent laparotomy for a perforation in the terminal ileum and recovered. The third patient underwent an open appendectomy and recovered. The fourth patient underwent emergent laparotomy for a perforated peptic ulcer and died from sepsis. Although the SARS-CoV-2 RNA was found in the feces of 3 patients and in the duodenal wall of the patient with perforated peptic ulcer, real time reverse transcriptase polymerase chain reaction (RT-PCR) examination of abdominal fluid was negative for the virus. The RT-PCR did not detect viral RNA in the wall of small intestine, appendix, gallbladder, bile, liver, and urine. Visceral fat (omentum) and abdominal subcutaneous fat of 4 patients were also not infected with the SARS-CoV-2. Although this limited experience did not show direct involvement of abdominal fluid and omentum, assessment in large series is suggested to provide answers about the safety of abdominal surgery in patients with COVID-19.