Inventory Management of Platelets in Hospitals: Optimal Inventory Policy for Perishable Products with Emergency Replenishments

Platelets are short-life blood components used in hospital blood transfusion centers. Excluding time for transportation, testing, and arrangement, clinically transfusable platelets have a mere three-day life-span. This paper analyzes a periodic review inventory system for such perishable products under two replenishment modes. Regular orders are placed at the beginning of a cycle. Within the cycle, the manager has the option of placing an emergency order, characterized by an order-up-to level policy. We prove the existence and uniqueness of an optimal policy that minimizes the expected cost. We then derive the necessary and sufficient conditions for the policy, based on which a heuristic algorithm is developed. A numerical illustration and a sensitivity analysis are provided, along with managerial insights. The numerical results show that, unlike typical inventory problems, the total expected cost is sensitive to the regular order policy. It also shows that the optimal policy is sensitive to changes in the expected demand, suggesting to decision makers the significance of having an accurate demand forecast

Public Awareness of Medical Imaging as a Source of Ionizing Radiation Exposure

Background. Biological effects of exposure to ionizing radiation (IR) are well known. Literature suggests most patients and physicians lack proficient understanding of risks associated with ionizing radiation. Our study goals were to: assess the extent to which productive, informed conversations regarding ionizing radiation are occurring between patients and providers; characterize public awareness of medical imaging procedures as sources of IR exposure; and investigate best practices in patientprovider communications. Methods. We developed and administered a 17-question survey to 303 adults at five locations across Chittenden County, Vermont, over a 6-week period in fall 2016. Descriptive and statistical analyses were conducted using SPSS. Results. The three age groups of respondents had different knowledge levels about ionizing radiation (p Conclusions/Recommendations. 1. A standard oral presentation for pre-imaging patient-provider communication, along with a written handout, be developed; 2. A section of the electronic medical record (also accessible through the patient portal) containing IR exposure be created for patients and physicians to track individuals\u27 information.https://scholarworks.uvm.edu/comphp_gallery/1249/thumbnail.jp

Investigating Genetic Determinants of Plasma Inositol Status in Adult Humans

BACKGROUND: Myo-inositol (MI) is incorporated into numerous biomolecules, including phosphoinositides and inositol phosphates. Disturbance of inositol availability or metabolism is associated with various disorders, including neurological conditions and cancers, while supplemental MI has therapeutic potential in conditions such as depression, polycystic ovary syndrome and congenital anomalies. Inositol status may be influenced by diet, synthesis, transport, utilisation and catabolism. OBJECTIVES: We aimed to investigate potential genetic regulation of circulating MI status and to evaluate correlation of MI concentration with other metabolites. METHODS: Gas chromatography mass spectrometry was used to determine plasma MI concentration of more than 2,000 healthy, young adults (aged 18-28 years) from the Trinity Student Study. Genotyping data was used to test association of plasma MI with SNPs in candidate genes, encoding inositol transporters and synthesising enzymes, and test for genome-wide association. We evaluated potential correlation of plasma MI with D-chiro inositol, glucose and other metabolites by Spearman's rank correlation. RESULTS: Mean plasma MI showed a small but significant difference between males and females (28.5 and 26.9 µM, respectively). Candidate gene analysis revealed several nominally significant associations with plasma MI, most notably for SLC5A11, encoding a sodium-coupled inositol transporter, also known as SMIT2 (sodium-dependent myo-inositol transporter 2). However, these did not survive correction for multiple testing. Subsequent testing for genome-wide association with plasma MI did not identify associations of genome-wide significance (p < 5 × 10-8). However, 8 SNPs exceeded the threshold for suggestive significant association with plasma MI concentration (p < 1 × 10-5), 3 of which were located within or close to genes: MTDH, LAPTM4B and ZP2. We found significant positive correlation of plasma MI concentration with concentration of D-chiro-inositol and several other biochemicals including glucose, methionine, betaine, sarcosine and tryptophan. CONCLUSION: Our findings suggest potential for modulation of plasma MI in young adults by variation in SLC5A11 which is worthy of further investigation

Molecular Mapping of the Thrombin-Heparin Cofactor II Complex

We used 55 Ala-scanned recombinant thrombin molecules to define residues important for inhibition by the serine protease inhibitor (serpin) heparin cofactor II (HCII) in the absence and presence of glycosaminoglycans. We verified the importance of numerous basic residues in anion-binding exosite-1 (exosite-1) and found 4 additional residues, Gln24, Lys65, His66, and Tyr71 (using the thrombin numbering system), that were resistant to HCII inhibition with and without glycosaminoglycans. Inhibition rate constants for these exosite-1 (Q24A, K65A, H66A, Y71A) thrombin mutants (0.02-0.38 x 10(8) m(-1) min(-1) for HCII-heparin when compared with 2.36 x 10(8) m(-1) min(-1) with wild-type thrombin and 0.03-0.53 x 10(8) m(-1) min(-1) for HCII-dermatan sulfate when compared with 5.23 x 10(8) m(-1) min(-1) with wild-type thrombin) confirmed that the structural integrity of thrombin exosite-1 is critical for optimal HCII-thrombin interactions in the presence of glycosaminoglycans. However, our results are also consistent for HCII-glycosaminoglycan-thrombin ternary complex formation. Ten residues surrounding the active site of thrombin were implicated in HCII interactions. Four mutants (Asp51, Lys52, Lys145/Thr147/Trp148, Asp234) showed normal increased rates of inhibition by HCII-glycosaminoglycans, whereas four mutants (Trp50, Glu202, Glu229, Arg233) remained resistant to inhibition by HCII with glycosaminoglycans. Using 11 exosite-2 thrombin mutants with 20 different mutated residues, we saw no major perturbations of HCII-glycosaminoglycan inhibition reactions. Collectively, our results support a "double bridge" mechanism for HCII inhibition of thrombin in the presence of glycosaminoglycans, which relies in part on ternary complex formation but is primarily dominated by an allosteric process involving contact of the "hirudin-like" domain of HCII with thrombin exosite-1

International Consensus Conference on Atopic Dermatitis II (ICCAD II * ): clinical update and current treatment strategies

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74915/1/j.1365-2133.148.s63.1.x.pd

Towards mirror symmetry \`a la SYZ for generalized Calabi-Yau manifolds

Fibrations of flux backgrounds by supersymmetric cycles are investigated. For an internal six-manifold M with static SU(2) structure and mirror \hat{M}, it is argued that the product M x \hat{M} is doubly fibered by supersymmetric three-tori, with both sets of fibers transverse to M and \hat{M}. The mirror map is then realized by T-dualizing the fibers. Mirror-symmetric properties of the fluxes, both geometric and non-geometric, are shown to agree with previous conjectures based on the requirement of mirror symmetry for Killing prepotentials. The fibers are conjectured to be destabilized by fluxes on generic SU(3)xSU(3) backgrounds, though they may survive at type-jumping points. T-dualizing the surviving fibers ensures the exchange of pure spinors under mirror symmetry.Comment: 30 pages, 3 figures, LaTeX; v2: references adde

Beta Functions of Orbifold Theories and the Hierarchy Problem

We examine a class of gauge theories obtained by projecting out certain fields from an N=4 supersymmetric SU(N) gauge theory. These theories are non-supersymmetric and in the large N limit are known to be conformal. Recently it was proposed that the hierarchy problem could be solved by embedding the standard model in a theory of this kind with finite N. In order to check this claim one must find the conformal points of the theory. To do this we calculate the one-loop beta functions for the Yukawa and quartic scalar couplings. We find that with the beta functions set to zero the one-loop quadratic divergences are not canceled at sub-leading order in N; thus the hierarchy between the weak scale and the Planck scale is not stabilized unless N is of the order 10^28 or larger. We also find that at sub-leading orders in N renormalization induces new interactions, which were not present in the original Lagrangian.Comment: 21 pages, LaTeX, 6 figures. Minor clarifications, references adde

The association between failed quit attempts and increased levels of psychological distress in smokers in a large New Zealand cohort

<p>Abstract</p> <p>Background</p> <p>Although the association between smoking status and poorer mental health has been well documented, the association between quit status and psychological distress is less clear. The aim of the present study is to investigate the association of smoking status and quit status with psychological distress.</p> <p>Methods</p> <p>Data for this study is from a single year of the Survey of Families, Income and Employment (SoFIE) conducted in New Zealand (2004/05) (n = 18,525 respondents). Smoking status and quit status were treated as exposure variables, and psychological distress (Kessler-10) was treated as the outcome variable. Logistic regression analyses were performed to determine the association of smoking with psychological distress in the whole adult population and quit status with psychological distress in the ex- and current-smoking population.</p> <p>Results</p> <p>Current smokers had higher rates of high and very high psychological distress compared to never smokers (adjusted odds ratio (aOR) = 1.45; 95% CI: 1.24-1.69). Unsuccessful quitters had much higher levels of high to very high levels of psychological distress (16%) than any other group. Moreover, compared to long-term ex-smokers, unsuccessful quitters had a much higher odds of high to very high levels of psychological distress (aOR = 1.73; 95% CI: 1.36-2.21).</p> <p>Conclusion</p> <p>These findings suggest that the significant association between smoking and psychological distress might be partly explained by increased levels of psychological distress among current smokers who made a quit attempt in the last year. This issue needs further study as it has implications for optimising the design of quitting support.</p

A new process-based and scale-aware desert dust emission scheme for global climate models – Part II: Evaluation in the Community Earth System Model version 2 (CESM2)

Desert dust is an important atmospheric aerosol that affects the Earth's climate, biogeochemistry, and air quality. However, current Earth system models (ESMs) struggle to accurately capture the impact of dust on the Earth's climate and ecosystems, in part because these models lack several essential aeolian processes that couple dust with climate and land surface processes. In this study, we address this issue by implementing several new parameterizations of aeolian processes detailed in our companion paper in the Community Earth System Model version 2 (CESM2). These processes include (1) incorporating a simplified soil particle size representation to calculate the dust emission threshold friction velocity, (2) accounting for the drag partition effect of rocks and vegetation in reducing wind stress on erodible soils, (3) accounting for the intermittency of dust emissions due to unresolved turbulent wind fluctuations, and (4) correcting the spatial variability of simulated dust emissions from native to higher spatial resolutions on spatiotemporal dust variability. Our results show that the modified dust emission scheme significantly reduces the model bias against observations compared with the default scheme and improves the correlation against observations of multiple key dust variables such as dust aerosol optical depth (DAOD), surface particulate matter (PM) concentration, and deposition flux. Our scheme's dust also correlates strongly with various meteorological and land surface variables, implying higher sensitivity of dust to future climate change than other schemes' dust. These findings highlight the importance of including additional aeolian processes for improving the performance of ESM aerosol simulations and potentially enhancing model assessments of how dust impacts climate and ecosystem changes.</p

Preoperative cardiac risk assessment in geriatric patients with hip fractures: an orthopedic surgeons’ perspective

Hip fracture is one of the most common orthopedic conditions and is associated with significant morbidity and mortality. With a progressively aging population, the annual incidence of hip fracture is expected to increase substantially. Emerging evidence suggests that early surgery (<24 h) minimizes complications secondary to immobilization, including orthostatic pneumonia and venous thromboembolism. Delayed surgical repair (>48 h) has been consistently demonstrated to be associated with an increased risk of 30-day and 1-year mortality. Nonetheless, early surgery necessitates a shorter time for preoperative medical preparation, in particular cardiac assessment. Patients who undergo emergent orthopedic surgery are therefore at greater risk of perioperative cardiac events than those who undergo elective surgery. In addition, the prompt triage system for preoperative cardiac assessment not only identifies patients at high risk of perioperative cardiac complications but also reduces unnecessary cardiac consultations for low-risk patients. We review the current recommendations for preoperative cardiac assessment adapted for patients with hip fracture and describe our current triage system for preoperative cardiac consultation