In-silico study of type 'B' condylar head fractures and evaluating the influence of two positional screw distance in two-screw osteosynthesis construct.

Clinical fixation screws are common in clinical practices to fix mandibular condyle fractures. Evidence suggests significance of 'working length' that is, distance between proximal and distal fixation screws in proximity to the fracture in orthopaedic implant design. In pursuit of stable implant-bone construct, this study aims to investigate the biomechanical performance of each configuration considered in the study and provide an optimal working length between the screws for clinical reference. Finite element models of virtually designed broken condyle as type 'B' were simulated and analysed in ANSYS Workbench. Screws are implanted according to previous literature at five varied distances 'd' maintaining five different ratios with the fracture length 'D'. Based on a literature review, boundary conditions, muscle traction forces and non-linear contacts were assigned to obtain precise results. Each case is considered an individual configuration and von Mises distribution, microstrain in bone, screw-bone interface micromotion and fracture dislocation were evaluated for all these configurations. Stress-shielding phenomenon is observed for maximum von Mises stresses in bone. Microstrain concentration was significant in cancellous bone in the vicinity of the screw around the fracture line. Configurations were compared based on the stress-strain along with micromotion to support the required amount of osseointegration between implant and bone. Presented data from all five conditions supported the assumption that under physiological loading conditions, the D3 configuration provided stability for fracture healing. Further research on screw shapes, diameters and material properties, or investigating the direction of forces within the screws could provide further insight into this topic.

Catalytic depolymerization of Kraft lignin to high yield alkylated-phenols over CoMo/SBA-15 catalyst in supercritical ethanol.

Lignin is generally considered to be a renewable and sustainable resource of aromatic chemicals. However, the depolymerization of Kraft lignin (KL) for the production of selective phenolic monomers presents a significant challenge due to its highly recalcitrant nature. Therefore, in this work, we investigated the effect of metal sites and acid active sites on Mo/SBA-15, Co/SBA-15 and CoMo/SBA-15 catalysts in supercritical ethanol for the depolymerization of KL to produce phenolic monomers. Ethanol was used as a hydrogen donor solvent instead of using external hydrogen. Results showed that the bimetallic CoMo/SBA-15 catalyst exhibited significantly higher catalytic activity compared to the monometallic, Co/SBA-15, Mo/SBA-15 or bare SBA-15. The highest phenolic monomers yield of 27.04 wt% was achieved at 290 °C for 4 h over CoMo/SBA-15 catalyst. The inter-unit linkages such as ß-O-4', ß-ß and α-O-4' in lignin were considerably cleaved during the catalytic depolymerization in supercritical ethanol. Meanwhile, higher functionality of carbonyl compounds was present in the non-catalytic bio-oil, while more alkylated phenols were produced over CoMo/SBA-15 catalyst. The major phenolic monomers identified in the catalytic bio-oil were 4-ethylguaiacol (9.15 wt%), 4-methylguaiacol (6.80 wt%), and 4-propylguaiacol (2.85 wt%). These findings suggest that the metal sites and abundant acid active sites of CoMo/SBA-15 had a synergistic effect toward the degradation of different linkages of lignin and production of selective phenolic monomers in bio-oils.

Mathematical Modelling and Optimization for Facile Synthesis of Structured Activated Carbon (ACs) from Adansonia kilima (Baobab) Wood Chips Integrating Microwave-Assisted Pyrolysis for the Elimination of Lead (II) Cations from Wastewater Effluents.

In this research, activated carbon (AC) was synthesized from ligno-cellulosic residues of Adansonia kilima (Baobab) wood chips (AKTW) using two-step semi-carbonization and subsequent pyrolysis using microwave-induced heating (MWP) in the presence of a mild activating agent of K2CO3. The influence of process input variables of microwave power (x1), residence time (y1), and amount of K2CO3 (z1) were analysed to yield superior quality carbon having maximum removal efficiencies (R1) for lead (II) cations from waste effluents, fixed carbon percentages (R2), and carbon yield percentages (R3). Analysis of variance (ANOVA) was used to develop relevant mathematical models, with an appropriate statistical assessment of errors. Level factorial response surface methodology (RSM) relying on the Box-Behnken design (BBD) was implemented for the experimental design. The surface area and porous texture of the samples were determined using Brunauer, Emmett, and Teller (BET) adsorption/desorption curves based on the N2 isotherm. Surface morphological structure was observed using field emission scanning electron microscopic (FESEM) analysis. Thermogravimetric analysis (TGA) was carried out to observe the thermal stability of the sample. Change in the carbon content of the samples was determined using ultimate analysis. X-ray diffraction (XRD) analysis was performed to observe the crystalline and amorphous texture of the samples. The retention of a higher proportion of fixed carbon (80.01%) ensures that the synthesized adsorbent (AKTWAC) will have a greater adsorption capacity while avoiding unwanted catalytic activity for our synthesized final sample.

Zinc-Bromine Rechargeable Batteries: From Device Configuration, Electrochemistry, Material to Performance Evaluation.

Zinc-bromine rechargeable batteries (ZBRBs) are one of the most powerful candidates for next-generation energy storage due to their potentially lower material cost, deep discharge capability, non-flammable electrolytes, relatively long lifetime and good reversibility. However, many opportunities remain to improve the efficiency and stability of these batteries for long-life operation. Here, we discuss the device configurations, working mechanisms and performance evaluation of ZBRBs. Both non-flow (static) and flow-type cells are highlighted in detail in this review. The fundamental electrochemical aspects, including the key challenges and promising solutions, are discussed, with particular attention paid to zinc and bromine half-cells, as their performance plays a critical role in determining the electrochemical performance of the battery system. The following sections examine the key performance metrics of ZBRBs and assessment methods using various ex situ and in situ/operando techniques. The review concludes with insights into future developments and prospects for high-performance ZBRBs.

Development and performance evaluation of an improved electric baking oven for baked products.

An improved electric baking oven was designed and fabricated using locally available materials for baking cakes and biscuits. Provisions of necessary adjustments were employed for ensuring uniform distribution of heat in all trays of the baking chamber. Its baking characteristics in terms of baking time, specific volume, and product quality in terms of sensory attributes were evaluated. The oven was found to be quite satisfactory in functioning for baking cakes and biscuits. Total time was only 15-28 min for baking the cake samples in the oven. On the other hand, comparatively, a bit longer time 18-35 min required for baking the biscuit samples. Baking cost was lesser in baking small-sized cakes and biscuits than those of large sized. The quality of baked products was better in terms of taste, color, flavor, texture, and appearance than ordinary market products. Loaf volume of each cake (with 4 × 5 × 8 cm3) was 100%, which gave specific volume of 652.8 cm3/kg. Similarly, the specific volume of biscuits was 810 cm3/kg. The electric baking oven is quite efficient in baking quality cakes and biscuits uniformly, which can be provided to rural small entrepreneurs for commercial manufacturing of biscuits and cakes.

Endosulfan affects embryonic development synergistically under elevated ambient temperature.

In the present study, we determined the developmental toxicity of endosulfan at an elevated ambient temperature using the zebrafish animal model. Zebrafish embryos of various developmental stages were exposed to endosulfan through E3 medium, raised under two selected temperature conditions (28.5 °C and an elevated temperature of 35 °C), and monitored under the microscope. Zebrafish embryos of very early developmental stages (cellular cleavage stages, such as the 64-cell stage) were highly sensitive to the elevated temperature as 37.5% died and 47.5% developed into amorphous type, while only 15.0% of embryos developed as normal embryos without malformation. Zebrafish embryos that were exposed concurrently to endosulfan and an elevated temperature showed stronger developmental defects (arrested epiboly progress, shortened body length, curved trunk) compared to the embryos exposed to either endosulfan or an elevated temperature. The brain structure of the embryos that concurrently were exposed to the elevated temperature and endosulfan was either incompletely developed or malformed. Furthermore, the stress-implicated genes hsp70, p16, and smp30 regulations were synergistically affected by endosulfan treatment under the elevated thermal condition. Overall, the elevated ambient temperature synergistically enhanced the developmental toxicity of endosulfan in zebrafish embryos.

Design and manufacturing of patient-specific Ti6Al4V implants with inhomogeneous porosity.

Stress shielding remains a challenge in orthopaedic implants, including total hip arthroplasty. Recent development in printable porous implants offers improved patient-specific solutions by providing adequate stability and reducing stress shielding possibilities. This work presents an approach for designing patient-specific implants with inhomogeneous porosity. A novel group of orthotropic auxetic structures is introduced, and their mechanical properties are computed. These auxetic structure units were distributed at different locations on the implant along with optimized pore distribution to achieve optimum performance. A computer tomography (CT) based finite element (FE) model was used to evaluate the performance of the proposed implant. The optimized implant and the auxetic structures were manufactured using laser powder bed-based laser metal additive manufacturing. Validation was done by comparing FE results with experimentally measured directional stiffness and Poisson's ratio of the auxetic structures and strain on the optimized implant. The correlation coefficient for the strain values was within a range of 0.9633-0.9844. Stress shielding was mainly observed in Gruen zones 1, 2, 6, and 7. The average stress shielding on the solid implant model was 56%, reduced to 18% when the optimized implant was used. This significant reduction in stress shielding can decrease the risk of implant loosening and create an osseointegration-friendly mechanical environment on the surrounding bone. The proposed approach can be effectively applied to the design of other orthopaedic implants to minimize stress shielding.

Patient-specific femoral implant design using metamaterials for improving load transfer at proximal-lateral region of the femur.

Loading configuration of hip joint creates resultant bending effect on femoral implants. So, the lateral side of femoral implant which is under tension retracts from peri­implant bone due to positive Poisson's ratio. This retraction of implant leads to load shielding and gap opening in proximal-lateral region, thereby allowing entry of wear particle to implant-bone interface. Retraction of femoral implant can be avoided by introducing auxetic metamaterial to the retracting side. This allows the implant to push peri­implant bone under tensile condition by virtue of their auxetic (negative Poisson's ratio) nature. To develop such implants, a patient-specific conventional solid implant was first designed based on computed-tomography scan of a patient's femur. Two types of metamaterials (2D: type-1) and (3D: type-2) were employed to design femoral meta-implants. Type-1 and type-2 meta-implants were fabricated using metallic 3D printing method and mechanical compression testing was conducted. Three finite element (FE) models of the femur implanted with solid implant, type-1 meta-implant and type-2 meta-implant were developed and analysed under compression loading. Significant correlation (R2 = 0.9821 and R2 = 0.9977) was found between the experimental and FE predicted strains of the two meta-implants. In proximal-lateral region of the femur, an increase of 7.1% and 44.1% von-Mises strain was observed when implanted with type-1 and type-2 meta-implant over the solid implant. In this region, bone remodelling analysis revealed 2.5% bone resorption in case of solid implant. While bone apposition of 0.5% and 7.7% was observed in case of type-1 and type-2 meta-implants, respectively. The results of this study indicates that concept of introduction of metamaterial to the lateral side of femoral implant can prove to provide higher osseointegration-friendly environment in the proximal-lateral region of femur.

A finite element study and mathematical modeling of lumbar pedicle screw along with various design parameters.

BACKGROUND: Lumbar pedicle screw is one of the most common and important elements in the field of lumbar surgery. It plays a great role in rectifying the spinal alignment and stabilization providing strength and stability to the affected area of spine. In spinal surgery, minimally invasive techniques and minor incisions are made which makes it less painful for the patients than the traditional methods. Moreover, the screws are not needed to be removed after the surgery which is yet another great advantage of the pedicle screw. METHOD: In this study, 3D Finite Element (FE) model of human L4 vertebrae is taken for analysis using image processing tool. Pedicle screw design with varying mechanical and geometrical properties has been carried out at different applied loads on it along with considering the effect of frictional forces between all contact surfaces. RESULT: Mathematical relationship among stress, strain, pitch of the screw and diameter have been developed for different thread profiles which will be beneficial for researchers for further development of pedicle screw implants. CONCLUSION: Results from the different analysis shows that bending stress on the screw for different loads at triangular pitch is higher than the trapezoidal. Hence, trapezoidal thread is efficacious than triangular thread. In case of vertebral bone, the magnitude of stress is less for trapezoidal screw than triangular and stress has a linear relationship with pitch length. In term of strain, triangular thread develops more strain than trapezoidal thread. A set of mathematical relation has been developed for different thread profile based on pitch length, stress and strain which gives the idea about von Mises stress and strain.

Prevalence of hepatitis B and C, and syphilis among aspirant migrant workers of Bangladesh.

Background: In Bangladesh, labour migration is a source of employment and workers' remittances are critical to poverty mitigation. The aim of this study was to assess the prevalence of hepatitis B, C, HIV, tuberculosis, syphilis, kidney and liver diseases along with presence of infections among aspirant migrant workers of Bangladesh. Method: This study was carried out from September-December 2019. We analysed data collected on screening tests of specific diseases of aspirant workers. For each test, the prevalence was computed with 95% confidence interval. Association between categorical data was determined by the Chi-square test. Results: A total of 2385 aspirants, 1988 (83.35%) males, aged between 18 and 65 years (29.76±6.578) were studied. Positive results for screening tests of HBsAg were 38 (1.6%,), anti-HCV were 2 (0.08%), TPHA were 25 (1.05%) and VDRL were 5 (0.21%) though no individual was positive for HIV and TB. Elevated level of SGOT (n=99, 4.2%), SGPT (n=322, 13.5%), RBS (n=57, 2.4%), bilirubin (n=46, 1.92%), creatinine (n=7, 0.3%) and ESR (n=19, 0.8%) were found in the workers. Conclusion: Diagnosis of diseases of workers is obligatory before going abroad to safeguard the health of the workers and residents of destination country. Consequently, it will contribute to reducing the global burden of infectious diseases.

Scientific issues of zinc-bromine flow batteries and mitigation strategies.

Zinc-bromine flow batteries (ZBFBs) are promising candidates for the large-scale stationary energy storage application due to their inherent scalability and flexibility, low cost, green, and environmentally friendly characteristics. ZBFBs have been commercially available for several years in both grid scale and residential energy storage applications. Nevertheless, their continued development still presents challenges associated with electrodes, separators, electrolyte, as well as their operational chemistry. Therefore, rational design of these components in ZBFBs is of utmost importance to further improve the overall device performance. In this review, the focus is on the scientific understanding of the fundamental electrochemistry and functional components of ZBFBs, with an emphasis on the technical challenges of reaction chemistry, development of functional materials, and their application in ZBFBs. Current limitations of ZBFBs with future research directions in the development of high performance ZBFBs are suggested.

Hepatic Histoplasmosis: An Update.

Histoplasma capsulatum is the most common cause of endemic mycosis in developing countries. It is a self-limited and asymptomatic disease in immunocompetent individuals but remains a frequent cause of opportunistic infection in patients with compromised immune status. Liver involvement as a part of disseminated histoplasmosis is well known. However, liver infection as a primary manifestation of histoplasmosis without evidence of primary lung involvement is rare. In conclusion, clinicians should be aware of isolated histoplasmosis affecting the hepatobiliary system, and careful evaluation is warranted to confirm the diagnosis. Given the appropriate clinical context, histoplasmosis should be considered in both immunocompetent and immunocompromised patients, regardless of pulmonary symptoms, in non endemic as well as endemic areas.

Design of patient specific basal dental implant using Finite Element method and Artificial Neural Network technique.

The bone conditions of mandibular bone vary from patient to patient, and as a result, a patient-specific dental implant needs to be designed. The basal dental implant is implanted in the cortical region of the bone since the top surface of the bone narrows down because of aging. Taguchi designs of experiments technique are used in which 25 optimum solid models of basal dental implants are modeled with variable geometrical parameters, viz. thread length, diameter, and pitch. In the solid models the implants are placed in the cortical part of the 3D models of cadaveric mandibles, that are prepared from CT data using image processing software. Patient-specific bone conditions are varied according to the strong, weak, and normal basal bone. A compressive force of 200 N is applied on the top surface of these implants and using finite element analysis software, the microstrain on the peri-implant bone ranges from 1000 to 4000 depending on the various bone conditions. According to the finite element data, it can be concluded that weak bone microstrain is comparatively high compared with normal and strong bone conditions. A surrogate artificial neural network model is prepared from the finite element analysis data. Surrogate model assisted genetic algorithm is used to find the optimum patient-specific basal dental implant for a better osseointegration-friendly mechanical environment.

Influence of implant parameters on biomechanical stability of TMJ replacement: A finite element analysis.

The articular disc reduces the stress distribution from the mandible to fossa. In total temporomandibular joint (TMJ) replacement, the implant is required to reduce the stress on fossa implant. Current studies lack standard and optimized parameters for the cylindrical dome on Christensen TMJ implant collar. This study briefed a novel TMJ implant head design and investigates the biomechanical behaviour by considering the articular disc. The radius of the head was varied with the height of the cylinder height to obtain the design of the experiment and the stress distribution was compared with an intact mandible-articular disc model by considering the viscoelastic property of the TMJ disc. The model was simulated at three different angles: 20°, 0° and -20° in the mediolateral direction to simulate the manducation. FEA analysis showed high stresses at the circular heads, and high strength is achieved with increased implant cylinder length and diameter. The results also showed a stress reduction of 50% on the fossa from the mandible. Hence, the newly designed head and suggested modifications may be used as a reference for further clinical improvement of Christensen TMJ as well as other TMJ implants.

Functional constipation in Bangladeshi school aged children: A hidden misty at community.

BACKGROUND: Constipation is a common problem in children and a frequent cause of hospital visit in both primary & specialized care, which needs proper evaluation & management. Presentation of constipation is variable among children. In Bangladesh there has been no published data regarding constipation in community among school aged children. AIM: To determine the magnitude of functional constipation and its risk factors in community among Bangladeshi school children. METHODS: This descriptive cross sectional study was conducted in different schools of Dhaka division, Bangladesh. All school aged children between 5-16 years of age who attended school were included in this study. Samples were collected randomly. Proper clinical history & physical examinations (without digital rectal examination) & available investigations (if done previously) were recorded. Diagnosis of functional constipation was done by Rome IV criteria and was compared with children without constipation. Children with any red flag sign, known chronic disease or any findings suggestive of organic disease and on treatment of constipation were excluded. Statistical analysis of the results was done by using Windows based software device with Statistical Packages for Social Science 20. For all statistical tests, P value of less than 0.05 was considered as statistically significant. RESULTS: Total study populations were 707 and male was 443 and female 264. Among them, 134 (19%) children had constipation. In constipated children, 78 children fulfilled the Rome IV criteria for functional constipation and it was 11% of total population. Mean age of children having functional constipation was 11.24 ± 3.54 years and Male female ratio was 1:1.78. Anorexia, nausea, abdominal pain, hard stool, blood with hard stool, alternate hard and loose stool and fecal mass in left iliac fossa were analyzed between two group and all were significantly higher in children with functional constipation group. Children of school, where toilet numbers were inadequate had 2.5 times more constipation risk in comparison to children of school with adequate toilet number (OR = 2.493, 95%CI: 1.214-5.120). Children who feel embarrassed to use toilet at school, had 3.6 times higher risk of constipation (OR = 3.552, 95%CI: 1.435-8.794). Here children with H/O affected sibs and parents/grandparents had 4 and 2.6 times more chance of constipation respectively in comparison to children without H/O affected sibs (OR = 3.977, 95%CI: 1.884-8.397) and parents/grandparents (OR = 2.569, 95%CI: 1.172-5.629). Children with inadequate fluid intake had 2 times more risk of constipation in comparison to children with adequate fluid intake (OR = 1.972, 95%CI: 1.135-3.426). Children who passed electronic screen time of > 2 h/d had 2 times more chance of constipation in comparison to children who passed electronic screen time < 2 h (OR = 2.138, 95%CI: 1.063-4.301). CONCLUSION: Constipation is not uncommon in Bangladeshi school aged children. Inadequate toilet number, family history of constipation, inadequate fluid intake, feeling embarrassed to use toilet at school, and electronic screen time for > 2 h/d were found as risk factors in the present study for functional constipation.

Same-Day Discharge Post-Transcatheter Aortic Valve Replacement During the COVID-19 Pandemic: The Multicenter PROTECT TAVR Study.

OBJECTIVES: The aim of this study was to determine the safety and efficacy of same-day discharge (SDD) after transcatheter aortic valve replacement (TAVR) during the COVID-19 pandemic. BACKGROUND: The COVID-19 pandemic has placed significant stress on health care systems worldwide. SDD in highly selected TAVR patients can facilitate the provision of essential cardiovascular care while managing competing COVID-19 resource demands. METHODS: Patient selection for SDD was at the discretion of the local multidisciplinary heart team, across 7 international sites. The primary outcome was a composite of cardiovascular death, stroke, myocardial infarction, all-cause readmission, major vascular complications, and new permanent pacemaker (PPM) implantation. RESULTS: From March 2020 to August 2021, 124 of 2,100 patients who underwent elective transfemoral TAVR were selected for SDD. The average age was 78.9 ± 7.8 years, the median Society of Thoracic Surgeons score was 2.4 (IQR: 1.4-4.2), and 32.3% (n = 40) had preexisting PPMs. There were no major vascular complications, strokes, or deaths during the index admission. One patient (0.8%) required PPM implantation for complete heart block and was discharged the same day. No patient required a PPM between discharge home and 30-day follow-up. The composite of cardiovascular death, stroke, myocardial infarction, all-cause readmission, major vascular complications, and new PPM at 30 days occurred in 5.7% patients (n = 6 of 106). CONCLUSIONS: SDD post-TAVR is safe and feasible in selected patients at low risk for adverse clinical events postdischarge. This strategy may have a potential role in highly selected patients even when the COVID-19 pandemic abates.

A comparative finite element analysis of artificial intervertebral disc replacement and pedicle screw fixation of the lumbar spine.

Titanium alloy-based Pedicle screw-rod fusion is a very common technique to provide higher fusion regularity than other methods. In recent times, Carbon-fibre-reinforced (CFR)-PEEK rod is used to better reduce the fusion rate. Alternatively, total disc replacement (TDR) is also very common for the non-fusion treatment method for degenerative disc disease (DDD). This study aims to investigate flexibility (ROM), stability, stress condition in implant, implant adjacent bone of the implanted lumbar spine during different physiological movements and loading environments. The finite element (FE) intact model of the lumbar spine (L2-L5) with two-level pedicle screw-rod fusion at L3-L4-L5 and two-level artificial disc replacement was developed. CFR-PEEK was taken for rod for semi-rigid fusion. UHMWPE was taken as core part of the artificial disc. The FE models were simulated under 6, 8 and 10 Nm moments in left right lateral bending, flexion and extension movements. The total ROM was reduced for two-level pedicle screw fixation and increased for the artificial disc replacement model during flexion extension compared to the intact spine. The total ROM was reduced by around 54% and 25% for two-level fixation and increased by 30% and 19.5% for artificial disc replacement spine, under flexion-extension and left-right lateral bending respectively. For screw fixation, the ROM increased by 15% and 18% reduced by 4.5% and 14% for disc replacement at the adjacent segments for flexion-extension and left-right lateral bending.

Effect of single and multilevel artificial inter-vertebral disc replacement in lumbar spine: A finite element study.

Degenerative disc disease (DDD) in lumbar spine is one of the major musculoskeletal disorders that cause low back pain (LBP). The intervertebral disc structure and dynamics of the lumbar spine are significantly affected by lumbar DDD, leading to a reduced range of motion (ROM), muscle weakness and gradual degradation. Spinal fusion and inter-vertebral disc replacement prostheses are two major surgical methods used for treating lumbar DDD. The aim of this present study is to examine biomechanical impacts of single level (L3-L4 and L4-L5) and multi level (L3-L4-L5) inter-vertebral disc replacement in lumbar spine (L2-L5) and to compare the performance with intact spine. Finite element (FE) analysis has been used to compare the mobility and stress distribution of all the models for four physiological movements, namely flexion, extension, left and right lateral bending under 6, 8 and 10 Nm moments. Spinal fusion implants completely restrict the motion of the implanted segment and increase disc stress at the adjacent levels. In contrast to that, the results single level ADR models showed closer ROM and disc stress to natural model. At the spinal segments adjacent to the implantation, single level ADR shows lower chance of disc degeneration. However, significantly increased ROM was observed in case of double level ADR.

Rural vs urban inequalities in stage at diagnosis for lung cancer.

OBJECTIVES: Early diagnosis of lung cancer increases the chance of survival. The aim of this study was to measure the relationship between geographic residence in Saskatchewan and stage of lung cancer at the time of diagnosis. MATERIALS AND METHODS: Retrospective cohort analysis of 2,972 patients with a primary diagnosis of either non-small cell cancer (NSCLC) or small cell lung cancer (SCLC) between 2007 and 2012 was performed. Incidence proportion of early and advanced stage cancer, and relative risk of being diagnosed with advanced-stage lung cancer relative to early-stage was calculated. RESULTS: Compared to urban Saskatchewan, rural Saskatchewan lung cancer patients had a higher relative risk of advanced stage NSCLC (relative risk [RR] = 1.11, 95% confidence interval [CI]: 1.01-1.22). Rural Saskatchewan was further subdivided into north and south. The relative risk of advanced stage NSCLC in rural north Saskatchewan compared to urban Saskatchewan was even greater (RR = 1.17, 95% CI: 1.03-1.31). Although not statistically significant, there was a trend for a higher incidence of advanced stage SCLC in rural and rural north vs urban Saskatchewan (RR = 1.16, 95% CI: 0.95-1.43 and RR = 1.22; 95% CI: 0.94-1.58, respectively). There was a higher incidence proportion of advanced stage NSCLC in rural areas relative to urban (31.6-34.4 vs 29.5 per 10,000 people). CONCLUSION: Patients living in rural Saskatchewan have higher incidence proportion of and were more likely to present with advanced stage NSCLC in comparison to urban Saskatchewan patients at time of diagnosis. This inequality was even greater in rural north Saskatchewan.

Design of patient specific bone stiffness mimicking scaffold.

The difference in stiffness of a patient's bone and bone implant causes stress shielding. Thus, implants which match the stiffness of bone of the patient result in better bone growth and osseointegration. Variation in porosity is one of the methods to obtain implants with different stiffness values. This study proposes a novel method to design biomimetic bone graft implant based on computed tomography (CT) scan data, that creates similar pre- and post-implant mechanical environment on peri-implant bone. The design methodology is demonstrated by taking three different sections of human femur bone, greater trochanter, diaphysis and epicondyle, with two different implant materials, Ti-6Al-4V and Ti-Mg. Bones from these three sections were replaced with porous implants of effective stiffness of replaced bone, as would have been required after a resection surgery. Models were simulated with physiological loading condition using finite element (FE) method. Variation of maximum von Mises stress and average strain on peri-prosthetic bone were found to be in the range of -6% to 10.7% and -7% to -17.9% for porous implants and 26% to 50% and -36% to -59% for solid implant respectively compared to natural bone. The results revealed that the porous implants, which have been designed based on CT scan data, can effectively produce mechanical response at peri-implant bone, which is very close to pre-implanted condition. Following this methodology, more osseointegration friendly mechanical environment can be achieved at peri-implant bone for any anatomical location independent of implant materials.