Evaluation of correction rates for titanium-alloy and cobalt-chrome-alloy rods in adolescent idiopathic scoliosis

Background: The customary treatment of AIS is spinal fusion with instrumentation using rigid rods. In parallel, agents such as, curve magnitude, points of fixation, level instrument selection, curve flexibility, kind of anchor rods used for patients and post-operative care are the main factors affecting the outcome of surgery.Methods: A total 50 patients was included in the study. The control group, which included 31 patients treated with Ti rods, was compared with an experimental group of 19 patients treated with CCM rods. Correction surgery was performed through posterior approach using rod-rotation maneuver after inserting a pedicle screw in each vertebrae within the fusion. Six-millimeter CCM and six-millimeter Ti rods were used in experimental and control groups, respectively. Pre and postoperative indices of coronal alignment and sagittal alignment were measured.Results: There was no statistical difference between the two groups for age, sex, Risser’s stage, preoperative Cobb’s angle, type and flexibility of curvature. The correction rate of thoracic curve was 71.4±10.2% for the CCM group and 71.8±6.1% for the Ti group. There were no statistical differences between the two groups for all coronal and sagittal factors (p>0.05).Conclusions: AIS cases with double curvature, there was no statistically significant difference between Ti and CCM rods for coronal and sagittal plane correction rates. The derivations from biomechanical studies do not translate into clinical situations

Optimal Control Promotional Policy for a New Product Incorporating Repeat Purchase in Segmented Market: A Control Theoretic Approach

This chapter considers an optimal control model to obtain dynamic promotional policies for a product considering a segmented market where first-time and additional repeat purchase sales are assumed to be generated through mass and differentiated promotions. Mass promotion is carried out in the whole market which reaches each segment with a fixed spectrum, and differentiated promotion is catered to each segment individually. The firm’s finite promotional resources are to be allocated for promoting a product at mass and segment levels of the market in a finite time period. The formulated control problem obtains optimal promotional effort policy for each segment using the maximum principle. The applicability of the proposed control model is illustrated through a numerical example by discretizing the model

Optimal Control Policy of a Production and Inventory System for multi-product in Segmented Market

In this paper, we use market segmentation approach in multi-product inventory - production system with deteriorating items. The objective is to make use of optimal control theory to solve the production inventory problem and develop an optimal production policy that maximize the total profit associated with inventory and production rate in segmented market. First, we consider a single production and inventory problem with multi-destination demand that vary from segment to segment. Further, we described a single source production multi destination inventory and demand problem under the assumption that firm may choose independently the inventory directed to each segment. This problem has been discussed using numerical example

Review of the State of Art: Ground Water Under the Direct Influence of Surface Water Programs

The objective of this study was to: 1. Evaluate the state of the art for groundwater under the direct influence (GWUDI) of surface water programs in the US and other countries. 2. Evaluate the existing groundwater under the influence (GUI) program in Texas with respect to hydrogeologic parameters and microbial indicators, including total and fecal coliform and microscopic particulate analyses (MPA). 3. Make recommendations to the Texas program based on a synthesis of best practices and elements from all reviewed programs. The driving force behind these evaluations is the fact that particles entrained in water can make the disinfection process ineffective because pathogens can be shielded within microscopic debris (LeChevallier et al., 1981). Further, some particles themselves, such as Giardia and Cryptosporidium cysts, can be pathogenic even if not encased in debris. Hence, groundwater sources that contain surface water-linked debris (algae, nematodes, etc.) that receive only disinfection have been implicated in many waterborne diseases.Bureau of Economic Geolog

Fluoride Alternatives in the Prevention of Dental Caries: A Review

There is no doubt that fluoride has been playing an important role in the prevention of dental caries and has been incorporated in various products (in both topical and systemic forms). However, few researchers consider fluoride to be a double edged sword as its use as an anticaries agent has been marked by various controversies because of the health concerns associated with the excessive use of the fluorides with its chronic use has been found to be associated with dental fluorosis, skeletal fluorosis, osteoporosis of long bones, carcinomas, renal and gall bladder calcification etc. The efficacy of fluorides to pit and fissured of the tooth surface is also questioned as its effect only seems to be limited to the smooth surface to the tooth. Hence, this review provides the readers with alternative fluoride free delivery mechanisms for caries prevention which can be used as an effective public health measure

Optimal pricing and promotional effort control policies for a new product growth in segmented market

Market segmentation enables the marketers to understand and serve the customers more effectively thereby improving company’s competitive position. In this paper, we study the impact of price and promotion efforts on evolution of sales intensity in segmented market to obtain the optimal price and promotion effort policies. Evolution of sales rate for each segment is developed under the assumption that marketer may choose both differentiated as well as mass market promotion effort to influence the uncaptured market potential. An optimal control model is formulated and a solution method using Maximum Principle has been discussed. The model is extended to incorporate budget constraint. Model applicability is illustrated by a numerical example. Since the discrete time data is available, the formulated model is discretized. For solving the discrete model, differential evolution algorithm is used

EVALI: A Review of the Vaping Related Lung Injury

Vaping or e-cigarettes were introduced to help people quit smoking tobacco but with every passing year, their demand has dramatically increased as compared to the traditional cigarettes. With the increase in the number of vapers, an alarming vaping related outbreak which was given an official name by the CDC: EVALI (Electronic cigarette or Vaping Product Associated Lung Injury). In the United States, until  January 21st, 2020 2051 cases have been reported from all 50 states with 60 deaths confirmed in 27 states and the district of Columbia. Not much is known about the cause of this outbreak but the possible culprits could be THC(Tetrahydrocannabinol) containing materials or Vitamin E Acetate. In order to protect the youth and the adults from such health hazards the government took a step by putting a ban on E-cigarettes. After the US states of Michigan & New York, India too, imposed a ban on the sale of such e-cigarettes. This review paper discusses about e-cigarettes and about its harmful effects that lead to EVALI in a person

Pore Geometry Effects on Intrapore Viscous to Inertial Flows and on Effective Hydraulic Parameters

In this article, the effects of different diverging-converging pore geometries were investigated, and the microscale fluid flow and effective hydraulic properties from these pores were compared with that of a pipe from viscous to inertial laminar flow regimes. The flow fields are obtained using computational fluid dynamics, and the comparative analysis is based on a new dimensionless hydraulic shape factor β, which is the specific surface scaled by the length of pores. Results from all diverging-converging pores show an inverse pattern in velocity and vorticity distributions relative to the pipe flow. The hydraulic conductivity K of all pores is dependent on and can be predicted from β with a power function with an exponent of 3/2. The differences in K are due to the differences in distribution of local friction drag on the pore walls. At Reynolds number (Re) ∼ 0 flows, viscous eddies are found to exist almost in all pores in different sizes, but not in the pipe. Eddies grow when Re →1 and leads to the failure of Darcy\u27s law. During non-Darcy or Forchheimer flows, the apparent hydraulic conductivity Ka decreases due to the growth of eddies, which constricts the bulk flow region. At Re \u3e 1, the rate of decrease in Ka increases, and at Re \u3e\u3e 1, it decreases to where the change in Ka ≈ 0, and flows once again exhibits a Darcy-type relationship. The degree of nonlinearity during non-Darcy flow decreases for pores with increasing β. The nonlinear flow behavior becomes weaker as β increases to its maximum value in the pipe, which shows no nonlinearity in the flow; in essence, Darcy\u27s law stays valid in the pipe at all laminar flow conditions. The diverging-converging geometry in pores plays a critical role in modifying the intrapore fluid flow, implying that this property should be incorporated in effective larger-scale models, e.g., pore-network models

The Role of Eddies inside Pores in the Transition from Darcy to Forchheimer Flows

We studied the role of intra-pore eddies, from viscous to inertial flows, in modifying continuum-scale flow inside pores. Flow regimes spanning Reynolds Number Re ∼ 0 to 1350 are divided into three zones - one zone follows Darcy flow, and the other two zones describe non-Darcy or Forchheimer flow. During viscous flows, i.e., Re \u3c 1, stationary eddies occupy about 1/5 of the pore volume. Eddies grow when Re \u3e 1, and their growth leads to the deviation from Darcy\u27s law and the emergence of Forchheimer flow manifested as a characteristic reduction in the apparent hydraulic conductivity Ka. The reduction in Ka is due to the narrowing of the flow channel which is a consequence of the growth in eddies. The two zones of Forchheimer flow correspond to the changes in rate of reduction in Ka, which in turn are due to the changes in eddy growth rate. Since the characteristics of Forchheimer flow are specific to pore geometry, our results partly explain why a variety of Forchheimer models are expected and needed for different porous media

Dynamic Advertising-based Goodwill Incorporating Fuzzy Environment in Segment-Specific Market

A new product's introduction to the market is greatly influenced by effective and enough advertising. In this paper, we have considered a problem in which the firm partitions the market into various segments to reduce costs associated with advertising and targets to maximize the total profit. By integrating single channel and differentiated advertising to segmented market, we extend Nerlove-goodwill Arrow's dynamic model in which advertising variables are control variables. It is assumed that the whole available budget is imprecise and fuzzy in nature in order to create a realistic model. Using necessity and possibility constraints, the optimal control model with fuzzy parameters is transformed into crisp form, and the Pontryagin Maximum principle is then used to solve the problem. Numerical examples are provided to support the theoretical analysis