bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of surgical simulation training on the complication rate of resident-performed phacoemulsification
Authors: Montrisuksirikun Chinnapat , Trinavarat Adisak , Atchaneeyasakul La-Ongsri
Published: June 2022

Objective

To study the effect of additional training with ophthalmic surgical simulation on the intraoperative complication rates of phacoemulsification performed by residents.

Methods and materials

This was a retrospective study of phacoemulsification surgeries performed by third-year residents at Siriraj Hospital. The operations were classified into two groups according to the experience of the surgeon in simulation training, that is, trained vs untrained. The main outcome was the total rate of complications. Other outcomes, including posterior capsule rupture, anterior capsulorhexis tearing, zonular dehiscence, retaining of lens material and intraocular lens (IOL) implantation methods, were also analysed.

Results

In total, 2971 operations were performed, comprising 1656 operations by 21 residents in the trained group, and 1315 by 20 residents in the untrained group. The total rate of complications in the simulator-trained group was lower than in the untrained group (13.6% vs 17.3%, p=0.005). Only the rate of retaining lens material showed a statistically significantly reduction (p<0.001); however, the rates of posterior capsule rupture, anterior capsulorhexis tearing and zonular dehiscence were not significantly different (p=0.08, 0.17, 0.23, respectively). The IOL implantation methods and surgical aphakia rate between the two groups were similar (p=0.44). In the subgroup analysis, the posterior capsule rupture rate in the first half of all cases performed by the residents was lower in the trained group (8.8% vs 12.4%, p=0.02).

Conclusion

Ophthalmic simulation training reduces the total rate of complications of resident-performed phacoemulsification. It also shortens the learning curve for cataract surgery training, as indicated by the decreased posterior capsule rupture rate in the initial cases of cataract surgery.
Shearing behaviour of vegetated soils with growing and decaying roots
Authors: Kamchoom Viroon , Leung Anthony Kwan , Boldrin David , Sakolpanya Tapakorn , Wu Zhaoyi , Likitlersuang Suched
Published: June 2022

Plant roots affect the soil shear strength, but the temporal dynamics of roots such as growth and decay due to different mortality means have rarely been considered. This study investigates the effects of root growth and decay on the changes in root biomechanical properties and the shearing behaviour of vegetated soils. Columns of compacted soils were grown with a grass species, Cynodon dactylon. The grass was grown for 6 months, followed by burning or herbicide applications to introduce root decay. The top part of each column was used for direct shear tests, whilst the roots collected from the bottom part were used for the measurements of root tensile and chemical properties. The vegetated soils displayed greater shear strength and larger dilatancy, which were attributable to the growth-induced increase in the root cellulose content, and thus the root tensile strength and modulus. Root decay, upon burning or herbicide use, caused significant declines in the root tensile properties, which translated to the reductions in soil dilatancy and soil shear strength lower than those of the fallow soil. Herbicide use introduced a much faster and significant loss of root reinforcement than burning because of the more severe decay and loss of root biomechanical properties.
Silver shiner,Notropis photogenis, fecundity and parasite infections during the reproductive period
Authors: Burbank Jacob , Drake D. Andrew R. , Power Michael
Published: June 2022

The reproductive period is a critical part of a species’ life history. Estimating species-specific fecundity can improve demographic models aimed at developing recovery targets for imperilled species. We provide egg diameter and fecundity estimates and develop a length–fecundity relationship for silver shiner, Notropis photogenis (Cope, 1865), a small-bodied freshwater species listed as Threatened under Canada's Species at Risk Act. Furthermore, we document the incidence of an acanthocephalan parasite, the thorny-headed worm, Leptorhynchoides thecatus (Linton, 1891), in the gastrointestinal tract of silver shiner, which is the first published record of the parasite in this species. Silver shiner egg diameters (mean ± standard deviation) were 0.61 ± 0.15 mm and ranged from 0.13 to 0.92 mm. Fecundity ranged from 311 to 2768 eggs and was significantly higher in age 2–3+ fish (1475 ± 570 eggs) compared with age 1+ fish (576 ± 270 eggs). We highlight that parasite infection negatively impacted the body condition of individuals and that additional work is needed to determine the impact of parasite infestation on reproductive output, recruitment, susceptibility to predation, and survival of silver shiner in Canada. The fecundity and egg diameter estimates for Canadian silver shiner provided here can be incorporated into future populations modelling for this threatened species.
Warped compactifications and holographic duality
Authors: Giedt Joel
Published: June 2022

We review warped compactifications of superstring theory with some attention to the limit in which these resemble “bottom-up” phenomenological models. In addition to some discussion of the original Klebanov–Witten and Klebanov–Strassler setups, we also touch on various generalizations of the geometry that have been considered. Various other systems with a holographic duality are also briefly reviewed. The point of this latter exploration is to illustrate how far beyond the standard AdS5 × S5 setup things have moved over the years.
Complex couplings in renormalization
Authors: Gégény F. , Nagy S.
Published: June 2022

The functional renormalization group equations are derived in Minkowski space–time for scalar models. It is shown that the couplings become complex, which can change the fixed point structure. New phases appear, and the models can build up complex fixed points.
On the discrete version of the Reissner–Nordström solution
Authors: Khatsymovsky V. M.
Published: June 2022

This paper generalizes our previous work on the discrete Schwarzschild-type solution in Regge calculus to the case of a charge. The known in the literature simplicial electro-dynamics retaining like Regge calculus geometric features of the continuum counterpart is incorporated into the formalism.

The functional integral provides a loose fixation of edge lengths around some scale and a perturbative expansion, for which we consider, in essence, finding the optimal starting (background) metric/field from the skeleton Regge and electro-dynamic equations. The simplest periodic simplicial structure and the expansion over metric/field variations between 4-simplices are considered. In the leading order of this expansion, the electromagnetic action, as we found earlier for the Regge action, is reducible to a finite-difference form of the continuum counterpart.

Instead of infinite continuous metric/field variables at the center, we have finite discrete variables; the discrete metric in the Schwarzschild-type coordinates turns out to change the sign of its variation when approaching the center from the nearest vertices, so that [Formula: see text] is positive at the center (the continuum [Formula: see text] tends to [Formula: see text] at the center). The metric/field in the neighborhood of the center and the curvature and the Kretschmann scalar at the center are estimated.
Translation in momentum space and minimal length
Authors: Valtancoli P.
Published: June 2022

We show that in the presence of the Snyder algebra the notion of translation in momentum space is modified to a formula similar to the relativistic addition of velocities. These results confirm the strict connection between Snyder algebra and the Lorentz group.
SEPnet: A Sustainable Model for a Collaborative Physics Network
Authors: Dunningham Jacob , Keenan Olivia , Soares Cristobel , Benson Veronica , Limbert Michelle , Hepwood Claire
Published: June 2022

The South East Physics network (SEPnet) is a collaboration among nine universities in the South East of England, working together to deliver excellence in physics. By sharing resources, we are able to add much more value to our departments, students, and subject than we could achieve individually. Our core ambitions include ensuring the sustainability of physics in our region, enhancing the employability of our students, delivering advanced training, securing the pipeline of future students, opening up new research opportunities and breaking down barriers to improve the accessibility of physics for everyone. We believe that SEPnet provides a tried and tested model that could be rolled out by others to improve the academic excellence of other disciplines in different regions.
A State Equation Approach to Harmonic Oscillation
Authors: Ban Koichi , Kajiyama Yuji
Published: June 2022

We discuss the motion of a harmonic oscillator using a state equation approach commonly applied in a modern control theory (MCT) of engineering. Instead of a second-order differential equation learnt by students in classes on mechanics, the state equation is written in a matrix form of a first-order differential equation of the state vector [Formula: see text]. We present the motion of a mass-spring-damper (MSD) system on an inclined plane and a simple pendulum in a viscous fluid. In the former case, we treat the gravitational force along the inclined plane as an input signal to the system. In the latter case, we treat the buoyant force and the drag force from the fluid as feedback to the system, controlling the final state of the system. The state equation approach presented in this article will help university students bridge the gap between physics and engineering.
The Rocket Equation and that Minus Sign: An Avoidable Pitfall in the Language of Physics
Authors: Koks Don
Published: June 2022

Derivations of the rocket equation that use a momentum-conservation argument are notorious for often encountering a problem that would produce an incorrect sign in their result, if it were not “fixed” in various ad hoc ways that can always be shown to be mathematically invalid. Here, we show that the problem of the unwanted minus sign typically (perhaps always) results from a misunderstanding of the language of calculus. When one adheres to a simple and fundamental rule of calculus notation, the derivation of the rocket equation becomes straightforward, and no unwanted minus sign appears.
Magnus Effect in Classroom: A New Low Cost Physics Lab
Authors: Ivchenko Vladimir
Published: June 2022

We consider a simple experiment, in which a paper cylinder rolls down an inclined ramp and falls off the edge of a table. If the cylinder is sufficiently light, the effects of the Magnus force on it will be visible, with its trajectory curving back below the edge of the table, instead of the usual parabolic path for a point mass. We construct a mathematical model that relates the density of air (among other physical quantities) to the vertical position of the cylinder when its horizontal displacement from the edge is maximum. Thus, with only a high-speed smartphone camera that captures the motion of the cylinder and any video analyzing tool, the air density in the classroom can be estimated.
Importance Analysis of Structural Seismic Demand Based on Support Vector Machine
Authors: Wang Xiuzhen , Xu Zhaoxia , Jiang Lianjie , Sun Chuanzhi , Yan Jun , Gao Li
Published: June 2022

Seismic demand analysis of structures plays an important role in the structural seismic calculation; however, studies on the importance analysis of seismic demand are limited. A new method based on a support vector machine (SVM) is proposed to analyze the importance of structural seismic demand and study the influence of random variables on structural seismic demand in this study, where the linear kernel function, Gauss kernel function, and polynomial kernel function are used in SVM. The time history analysis of the steel-reinforced concrete (SRC) frame structures has been carried out by the finite element software OpenSees under the action of different seismic records. Four kinds of seismic demand of the SRC frame structure are analyzed in this study, which are top displacement, maximum floor acceleration, base shear, and maximum interstory drift angle, respectively. Importance indexes of the four kinds of structural seismic demand are in good agreement with those of the Monte Carlo (MC) numerical simulation method and Tornado graphic method, which verify the accuracy of the proposed method. Moreover, the sample size of the proposed method is greatly smaller than that of the MC method. Therefore, the computation efficiency has been improved significantly by the proposed method.
Analytical Analysis of Fractional-Order Newell-Whitehead-Segel Equation: A Modified Homotopy Perturbation Transform Method
Authors: Iqbal Naveed , Albalahi Abeer M. , Abdo Mohammed S. , Mohammed Wael W.
Published: June 2022

This paper has applied a hybrid method called the homotopy perturbation transformation technique to solve fractional-order Newell-Whitehead-Segel equations. First, we used the Yang transformation to the given problem, and then, the homotopy perturbation technique was implemented to complete the procedure of the suggested method. The proposed method is simplified and requires a small calculation to achieve the solution to the targeted problem. Moreover, the derived results are in close contact with the exact results of the given models. Three examples are solved to confirm and show the feasibility of the present scenario. The findings obtained from the proposed procedure have also been in excellent alignment with other technique outcomes. It is shown that the proposed approach is effective, consistent, and straightforward to apply to various relevant problems in engineering and science.
International Trade Transportation Cost Based on Internet of Things-Assisted Wireless Network Virtualization
Authors: Wang Yue , Li Wei
Published: June 2022

With the development of information technology and the advent of the Internet of Everything era, more and more fields have begun to use the convenience of the Internet of Things to solve problems. International trade is a form of trade that develops rapidly under the world trade situation, and the optimization of transportation costs has always been an important issue to be solved in international trade. Wireless network virtualization (WNV for short) is an abstraction of the concept of wireless network connectivity. It allows remote users to access an organization’s internal network as if it was a physical connection. WNV has the characteristics of safety assurance, service quality assurance, scalability, flexibility, and manageability, and it has many advantages in the transportation industry. This paper is aimed at studying an IoT-assisted WNV technology to analyze the cost of international trade transportation. This paper proposes a resource optimization algorithm based on WNV and uses this algorithm to test the designed IoT-assisted WNV model. The test results show that using the WNV model can reduce the cost of transportation price by 3.13 yuan per ton per month on average, and the improved transportation efficiency is an average increase of 0.152 tons per kilometer per hour. The total transportation cost obtained by the WNV algorithm model in this paper is significantly reduced, and the transportation cost calculation effect using this model is better.
Visual Outcomes of Microkeratome-Assisted Anterior Lamellar Keratoplasty in Keratoconus: 5-Year Results
Authors: Ashor Ahmed Rashad , El-Agha Mohamed-Sameh H. , Nagaty Mohamed Waleed , Darwish Essam Abdel Ghaffar
Published: June 2022

Purpose. To report 5-year results of microkeratome-assisted anterior lamellar keratoplasty (MK-ALK) in cases of keratoconus. Methods. Patients with advanced keratoconus and the thinnest corneal location 300 μ or more were recruited. A Carriazo–Barraquer microkeratome was used to remove a 200-μ cap from the recipient cornea, and to prepare a 300-μ anterior stromal graft from a donor cornea. A full-thickness crescentic incision was made in the posterior stromal recipient bed using a 6.5-mm suction trephine. The donor was sutured to the recipient bed using interrupted nylon sutures. The minimum follow-up was five years. Results. Twelve eyes of 12 patients were included. The mean age was 26 ± 8 years. None of the patients required conversion to penetrating keratoplasty. Mean logMAR uncorrected and best spectacle-corrected visual acuity, respectively, improved from 1.56 ± 0.24 and 1.18 ± 0.32 preoperatively, to 0.63 ± 0.38 and 0.18 ± 0.12, five years after surgery (

P
=
0.001

for both). There was also a statistically significant reduction of mean manifest spherical equivalent, refractive cylinder, and mean keratometry readings. Posterior stromal striations occurred in all patients immediately after surgery but resolved after a maximum of 3 months. At five-years, anterior segment optical coherence tomography revealed a clear interface in all cases and a mean graft thickness of 328 ± 27 μ. Conclusion. MK-ALK is a safe and effective procedure for advanced keratoconus. Where feasible, it may be the best choice for patients at high risk of poor outcomes with penetrating keratoplasty, such as young patients with atopic keratoconjunctivitis or Down’s syndrome.
Immediate versus Delayed Implantation for Single-Tooth Restoration of Maxillary Anterior Teeth: A Comparative Analysis on Efficacy
Authors: Chen Zhimin , Zhang Shuhuai , Zhou Jun , Liang Hongling
Published: June 2022

Objective. The present research is aimed at determining the efficacy of immediate implantation (II) and delayed implantation (DI) for single-tooth restoration of maxillary anterior teeth. Methods. From February 2019 to June 2020, 80 patients who received single-tooth restoration of maxillary anterior teeth in Suzhou Kowloon Hospital, Shanghai Jiaotong University School of Medicine, were included, among which 38 cases with DI restoration were used as the control group (CG), and the remaining 42 cases with II were used as the research group (RG). The complications that occurred were recorded. Besides, subjective satisfaction (Visual Analogue Scale (VAS)), aesthetic effect after anterior teeth trauma restoration (Pink Esthetic Score (PES)), aesthetics of dental hard tissue (White Esthetic Score (WES)), pocket depth assessed by pure titanium periodontal probe, implant stability (Implant Stability Quotient (ISQ)), and oral health-related quality of life (Oral Health Impact Profile- (OHIP-) 14) were evaluated. Attachment height, general look, color, and chewing function were all much higher in RG than in CG, according to the evaluation results. Furthermore, at 3 months, 6 months, and 12 months after surgery, RG had greater PES, WES, ISQ, and OHIP-14 scores, while the periodontal depth was decreased. In both groups of patients, the incidence of complications was similar, with no discernible differences.
Fixed Assets Positioning Management Based on Nonlinear Difference Algorithm
Authors: Wu Mingming
Published: June 2022

Fixed assets are an enterprise’s core means of production and a vital asset for the enterprise’s sustainability. Good fixed asset management not only helps to enhance asset utilization but also helps to prevent idleness and asset loss, both of which are vital in the success of the enterprise. To improve fixed asset management, it needs not only a good asset management system but also advanced asset monitoring and management technology. As a result, to address the issues of difficult positioning, tracking, and low management efficiency in enterprise’s asset management, this paper optimizes the commonly used the LANDMARC positioning algorithm and implements an improved algorithm based on Lagrange nonlinear interpolation. It is also used in fixed asset positioning management to overcome the problem of increasing the density of auxiliary tags to enhance positioning accuracy, which leads to higher costs and greater radio frequency interference. Simultaneously, a set of RFID-based fixed asset management systems was built and implemented, starting with the application requirements of enterprises and combining the optimization algorithm with FRID technology. Finally, a simulation experiment on the application of the Lagrange nonlinear interpolation algorithm in fixed asset positioning management is carried out and a comparison with other algorithms is performed. According to the simulation findings, the new algorithm has enhanced the positioning accuracy. The system can perform all-around dynamic tracking and positioning management of diverse assets, optimize the use efficiency and management level of assets, and improve the intelligent level of enterprise asset management.
Three-Tier Computing Platform Optimization: A Deep Reinforcement Learning Approach
Authors: Chidume Chidiebere Sunday , Okopi Solomon Inalegwu , Sesay Taiwo , Materu Irene Simon , Asenso Theophilus Quachie
Published: June 2022

The increasing number of computing platforms is critical with the increasing trend of delay-sensitive complex applications with enormous power consumption. These computing platforms attach themselves to multiple small base stations and macro base stations to optimize system performance if appropriately allocated. The arrival rate of computing tasks is often stochastic under time-varying wireless channel conditions in the mobile edge computing Internet of things (MEC IoT) network, making it challenging to implement an optimal offloading scheme. The user needs to choose the best computing platforms and base stations to minimize the task completion time and consume less power. In addition, the reliability of our system in terms of the number of computing resources (power, CPU cycles) each computing platform consumes to process the user’s task efficiently needs to be ascertained. This paper implements a computational task offloading scheme to a high-performance processor through a small base station and a collaborative edge device through macro base stations, considering the system’s maximum available processing capacity as one of the optimization constraints. We minimized the latency and energy consumption, which constitute the system’s total cost, by optimizing the computing platform choice, base station’s choice, and resource allocation (computing, communication, power). We use the actor-critic architecture to implement a Markov decision process that depends on deep reinforcement learning (DRL) to solve the model’s problem. Simulation results showed that our proposed scheme achieves significant long-term rewards in latency and energy costs compared with random search, greedy search, deep Q-learning, and the other schemes that implemented either the local computation or edge computation.
Design of Web Security Penetration Test System Based on Attack and Defense Game
Authors: Song Bing , Sun Li , Qin Zhihong
Published: June 2022

Some sensitive data in the network will be leaked due to the loopholes or weaknesses of the web system itself, which will bring potential harm to the society or the public. Aiming at this, this study carries out the design of web security penetration test system. A test scheme comparing single method with an automatic comprehensive test method is designed. Based on this scheme, an automatic penetration test system script used under the terminal operation page is tested and designed. A security evaluation algorithm based on the prediction results of the game between attack and defense is proposed. Through this algorithm, different website systems are evaluated and scored, and the test results are compared through scoring. The automatic penetration test integration system designed and implemented in this study can meet the main objectives of web security and the protection requirements of websites against general, routine, and universal security attacks. The proposed evaluation algorithm is more detailed, accurate, and reference in scoring.
Multisource Target Data Fusion Tracking Method for Heterogeneous Network Based on Data Mining
Authors: Guo Hongyan , Li Xintao
Published: June 2022

This research is on heterogeneous network fusion method of multisource target data based on data mining. Firstly, it is a distributed storage structure model for building heterogeneous network multisource target data. Then, using the phase space reconstruction method, a grid distribution structure model for data fusion tracking is constructed, and realize visual scheduling and automatic monitoring of multisource target data. Finally, according to the feature extraction results, analyze the statistical characteristics of multisource target data in heterogeneous networks, combined with the fuzzy tomographic analysis method, multilevel fusion, and adaptive mining of multisource target data, extract the associated feature quantities in it, and realize the fusion tracking of data. The simulation results show that, in relatively simple heterogeneous networks, the feature mining error of the proposed method is nearly 2.11% lower than the two traditional methods. In relatively complex heterogeneous networks, the feature mining error of the proposed method is nearly 6.48% lower than the two traditional methods. It can be seen that this method has better adaptability for fusion tracking of heterogeneous network multisource target data, the anti-interference ability is strong, and the tracking accuracy in the data fusion tracking process is also improved.
English-Assisted Teaching Evaluation System Based on Artificial Intelligence and Rasch Model
Authors: Guo Erying , Sun Li
Published: June 2022

In order to improve the effect of English teaching in colleges and universities, this paper analyzes the English teaching process and combines the English teaching evaluation system and the Rasch model to construct an English teaching evaluation system. Moreover, this paper analyzes the needs of English teaching evaluation and uses the mixed Rasch model in the item reflection theoretical model to study the potential classification problems of teaching. At the same time as the optimal parameter estimation, the potential optimal classification ratio is found, and it is used as the basis for the classification of English teaching grades. In addition, this paper combines the Rasch model to construct the English-assisted teaching evaluation system and analyzes the system framework and workflow. The experimental research shows that the evaluation system of college English teaching process based on the Rasch model proposed in this paper has a good effect.
Using Hierarchical Modeling in Genetic Association Studies with Multiple Markers: Application to a Case-Control Study of Bladder Cancer
Authors: Hung Rayjean J. , Brennan Paul , Malaveille Christian , Porru Stefano , Donato Francesco , Boffetta Paolo , Witte John S.
Published: June 2022

Background: Genetic association studies are generating much information, usually in the form of single nucleotide polymorphisms in candidate genes. Analyzing such data is challenging, and raises issues of multiple comparisons and potential false-positive associations. Using data from a case-control study of bladder cancer, we showed how to use hierarchical modeling in genetic epidemiologic studies with multiple markers to control overestimation of effects and potential false-positive associations. Methods: The data were first analyzed with the conventional approach of estimating each main effect individually. We subsequently employed hierarchical modeling by adding a second stage (prior) model that incorporated information on the potential function of the genes. We used an empirical-Bayes approach, estimating the residual effects of the genes from the data. When the residual effect was set to zero, we instead used a semi-Bayes approach, in which they were pre-specified. We also explored the impact of using different second-stage design matrices. Finally, we used two approaches for assessing gene-environment interactions. The first approach added product terms into the first-stage model. The second approach used three indicators for subjects exposed to gene-only, environment-only, and both genetic and environmental factors. Results: By pre-specifying the prior second-stage covariates, the estimates were shrunk to the mean of each pathway. The conventional model detected a number of positive associations, which were reduced with the hierarchical model. For example, the odds ratio for myeloperoxidase (G/G, G/A) genotype changed from 3.17 [95% confidence interval (CI), 1.32-7.59] to 1.64 (95% CI, 0.81-3.34). A similar phenomenon was observed for the gene-environment interactions. The odds ratio for the gene-environment interaction between tobacco smoking and N-acetyltransferase 1 fast genotype was 2.74 (95% CI, 0.68-11.0) from the conventional analysis and 1.24 (95% CI, 0.80-1.93) from the hierarchical model. Conclusion: Adding a second-stage hierarchical modeling can reduce the likelihood of false positive via shrinkage toward the prior mean, improve the risk estimation by increasing the precision, and, therefore, represents an alternative to conventional methods for genetic association studies.
Missense Mutations in the BRCT Domain of BRCA-1 from High-Risk Women Frequently Perturb Strongly Hydrophobic Amino Acids Conserved among Mammals
Authors: Figge Meaghan A. , Blankenship Lynda
Published: June 2022

Inherited missense mutations in the tumor suppressor gene, BRCA-1, may predispose to breast or ovarian cancer, but the exact effects on the protein are generally unknown. The COOH-terminal region of BRCA-1 encodes two BRCT repeats, which are partially conserved in mammalian species (human, dog, rat, and mouse; 60% amino acid identity). A bioinformatic analysis was conducted to evaluate 246 BRCT missense mutations from high-risk breast and/or ovarian cancer patients (reported in the NIH Breast Cancer Information Core database). It was hypothesized that amino acids conserved in evolution would be disproportionately targeted by the mutations and that conserved amino acids with strongly hydrophobic side chains would be disproportionately perturbed. A statistical model was developed, and χ2 tests were used to determine whether missense mutations are randomly distributed throughout the BRCT repeats or whether they disproportionately target certain amino acids. The results showed that missense mutations disproportionately target amino acids that are identical in all four mammals (χ2 = 46.01, P < 0.001). In addition, missense mutations disproportionately perturb conserved amino acids with strongly hydrophobic side chains (χ2 = 68.57, P < 0.001) and alter the strongly hydrophobic property. The two most frequently observed known cancer-predisposing missense mutations in the BRCT repeats, M1775R and A1708E, conform to this pattern. These results suggest that missense mutations affecting highly conserved amino acids with strongly hydrophobic side chains can disturb important features of the BRCA-1 protein and may play a role in breast and ovarian cancer formation.
The Effect of Cruciferous and Leguminous Sprouts on Genotoxicity, In vitro and In vivo
Authors: Gill Chris I.R. , Haldar Sumanto , Porter Shelley , Matthews Sinead , Sullivan Shane , Coulter Jimmy , McGlynn Hugh , Rowland Ian
Published: June 2022

Vegetable consumption is associated with a reduced risk of colorectal cancer, which is the second most common cancer after lung/breast cancer within Europe. Some putative protective phytochemicals are found in higher amounts in young sprouts than in mature plants.

The effect of an extract of mixed cruciferous and legume sprouts on DNA damage induced by H2O2 was measured in HT29 cells using single cell microgelelectrophoresis (comet). Significant antigenotoxic effect (P ≤ 0.05) was observed when HT29 cells were pre-incubated with the extract (100 and 200 μL/mL) for 24 hours and then challenged with H2O2. A parallel design intervention study was carried out on 10 male and 10 female healthy adult volunteers (mean age = 25.5 years) fed 113 g of cruciferous and legume sprouts daily for 14 days. The effect of the supplementation was measured on a range of parameters, including DNA damage in lymphocytes (comet), the activity of various detoxifying enzymes (glutathione S-transferase, glutathione peroxidase, and superoxide dismutase), antioxidant status using the ferric reducing ability of plasma assay, plasma antioxidants (uric acid, ascorbic acid, and α-tocopherol), blood lipids, plasma levels of lutein, and lycopene. A significant antigenotoxic effect against H2O2-induced DNA damage was shown in peripheral blood lymphocytes of volunteers who consumed the supplemented diet when compared with the control diet (P = 0.04). No significant induction of detoxifying enzymes was observed during the study, neither were plasma antioxidant levels or activity altered. The results support the theory that consumption of cruciferous vegetables is linked to a reduced risk of cancer via decreased damage to DNA.
Calcium from Diet and Supplements is Associated With Reduced Risk of Colorectal Cancer in a Prospective Cohort of Women
Authors: Flood Andrew , Peters Ulrike , Chatterjee Nilanjan , Lacey James V. , Schairer Catherine , Schatzkin Arthur
Published: June 2022

We investigated the association between calcium intake and colorectal cancer in a prospective cohort of 45,354 women without a history of colorectal cancer who successfully completed a 62-item National Cancer Institute/Block food-frequency questionnaire. Women were followed for an average of 8.5 years, during which time 482 subjects developed colorectal cancer. We used Cox proportional hazards models, with age as the underlying time metric, to estimate risk of colorectal cancer. Cut points between quintiles of energy-adjusted dietary calcium were 412, 529, 656, and 831 mg/day. We created categories for calcium from supplements as follows: 0 mg/day (n = 25,441), 0 to 400 mg/day (n = 9,452), 401 to 800 mg/day (n = 4,176), and >800 mg/day (n =6,285). Risk ratios and confidence intervals (95% CI) for increasing quintiles of dietary calcium relative to the lowest quintile were 0.79 (0.60-1.04), 0.77 (0.59-1.02), 0.78 (0.60-1.03), and 0.74 (0.56-0.98), Ptrend = 0.05. For increasing categories of calcium from supplements, the risk ratios (and 95% CI) relative to no supplement use were 1.08 (0.87-1.34), 0.96 (0.70-1.32), and 0.76 (0.56-1.02), Ptrend = 0.09. Simultaneously high consumption of calcium from diet and calcium from supplements resulted in even further risk reduction, RR = 0.54 (95% CI, 0.37-0.79) compared with low consumption of both sources of calcium. These data indicate that a difference of < 400 to > 800 mg of calcium per day was associated with an approximately 25% reduction in risk of colorectal cancer, and this reduction in risk occurred regardless of the source of the calcium (i.e., diet or supplements).
Genetic Polymorphisms in the IGFBP3 Gene: Association with Breast Cancer Risk and Blood IGFBP-3 Protein Levels among Chinese Women
Authors: Ren Zefang , Cai Qiuyin , Shu Xiao-Ou , Cai Hui , Li Chun , Yu Herbert , Gao Yu-Tang , Zheng Wei
Published: June 2022

Cumulative evidence suggests that insulin-like growth factors (IGF) play an important role in the etiology of breast cancer. The IGF binding proteins regulate the action of IGFs, and >90% of circulating IGFs are bound to IGFBP-3. We evaluated the associations of five (A−202C, G227C, C3804G, 5606InsA, and C5827T) genetic polymorphisms in the IGFBP3 gene with breast cancer risk and the blood IGFBP-3 protein level in a population-based, case-control study conducted among Chinese women in Shanghai. Genomic DNA samples from 1,193 incident breast cancer patients and 1,310 community controls were genotyped for IGFBP3 polymorphisms. Blood IGFBP-3 levels were determined for 390 controls. A 30% to 60% elevated risk of breast cancer was found to be associated with homozygosity for the variant allele in polymorphisms A−202C, G227C, 5606InsA, and C5827T. Carrying the variant allele in C3804G was also associated with an increased risk. About 13.5% of cases and 9.7% of controls had one or more of the above risk genotypes, resulting in odds ratio [OR; 95% confidence interval (95% CI)] of 1.4 (1.0-1.9). The ORs (95% CIs) were 1.3 (1.0-1.8) and 1.7 (1.1-2.5) for women with one to two and three to five risk genotypes, respectively (P for trend < 0.01). Four common haplotypes for the IGFBP3 gene were identified. Compared with the haplotype containing only the wild-type allele in the five loci, the haplotype with the variant allele in all sites was associated with an elevated risk of breast cancer (OR 1.4, 95% CI 1.0-1.9), particularly among younger women (OR 2.3, 95% CI 1.3-3.9). With the exception of C3804G, in which no homozygote was identified, the level of circulating IGFBP-3 was reduced in a dose-response manner with an increasing number of variant alleles in each of the other four polymorphic sites (P for trend < 0.05). These results indicated that IGFBP3 polymorphisms may be associated with the level of blood IGFBP-3 protein and an increased risk of breast cancer.
Use of Oral Contraceptives, Alcohol, and Risk for Invasive Breast Cancer
Authors: Dumeaux Vanessa , Lund Eiliv , Hjartåker Anette
Published: June 2022

The aim of our study was to examine how the use of oral contraceptives (OCs) interact with alcohol on breast cancer risk within the large prospective follow-up study, Norwegian Women and Cancer Study. Between 1991 and 1997, women aged 30 to 70 years were drawn at random from the central person register and mailed an invitation. Follow-up information was collected throughout 2001 by linkage to national registries. Only women (n = 86,948) with complete information on alcohol consumption and duration of OC use were included in the present analysis. A total of 1,130 invasive breast cancers were diagnosed during 618,638 person-years of follow-up. Consumption of ≥10.0 g/d alcohol was associated with a breast cancer relative risk (95% confidence interval) of 1.69 (1.32-2.15), consistent with a linear relationship (P for trend < 0.0001). Among alcohol consumers, an excess risk of breast cancer was observed for total duration of OC use only among women who consumed <5 g/d alcohol (P for trend = 0.0009). We observed a negative interaction between duration of OC use and alcohol consumption effects (P for interaction = 0.01). After stratification on menopausal status, the association between high alcohol intake and breast cancer was more prominent among postmenopausal women than among premenopausal women (P for heterogeneity = 0.01). No interaction between alcohol and duration of OC use were significant after stratification on menopausal status. Our findings in conjunction with biological data imply that alcohol and OCs have antagonistic effects on breast cancer risk through a common pathway. Whether the interactive effect differs according to menopausal status remains unclear and needs further investigations.
Benzo(a)pyrene Diolepoxide (BPDE)-DNA Adduct Levels in Leukocytes of Smokers in Relation to Polymorphism of CYP1A1, GSTM1, GSTP1, GSTT1, and mEH
Authors: Lodovici Maura , Luceri Cristina , Guglielmi Francesco , Bacci Chiara , Akpan Victor , Fonnesu Maria Luisa , Boddi Vieri , Dolara Piero
Published: June 2022

Benzo(a)pyrene [B(a)P] diolepoxide (BPDE)-DNA adducts were measured in the leukocytes of 41 healthy smokers using high-performance liquid chromatography coupled with a fluorimetric detector. The correlation between exposure to B(a)P through smoking and BPDE-DNA adduct levels was poor (r = 0.31), although subjects in the high exposure group [B(a)P > 50 ng/d] had a slightly higher level of adducts compared with the less exposed group (mean ± SE, 1.70 ± 0.3 versus 1.09 ± 0.1; P = 0.057). We studied the effect on BPDE-DNA adducts of individual variations in genes controlling B(a)P metabolism, classifying subjects in “low-risk” and “high-risk” genotypes for smoking-related B(a)P DNA damage. The high-risk group included subjects characterized by a combination of increased B(a)P activation [cytochrome P450 1A1 (CYP1A1) MspI and/or exon 7 Ile462Val allele variants and microsomal epoxide hydrolase (mEH) fast activity] and decreased deactivation ability [presence of glutathione S-transferase M1 (GSTM1) null allele and wild-type glutathione S-transferase P1 (GSTP1)]. The low-risk group included smokers with lower B(a)P activation (wild-type CYP1A1, low or intermediate mEH activity) and higher deactivation capacity (active GSTM1, GSTP1 Ile105Val allele). Subjects in the low-risk group had lower levels of BPDE-DNA adducts compared with subjects in the high-risk genotype group; this difference was significant using two markers (CYP1A1 and GSTM1, median ± SD, 0.77 ± 1.16 versus 1.89 ± 0.39; P = 0.03) or three markers (CYP1A1, GSTM1, and GSTP1, median ± SD, 0.66 ± 0.93 versus 1.43 ± 1.17; P = 0.013). The discrimination between groups was reduced when including mEH as an additional marker (P = 0.085). In conclusion, CYP1A1, GSTM1, and GSTP1 genotyping seems to be a risk predictor of BPDE-DNA adduct formation in leukocytes.
Cancer Prevention Strategies That Address the Evolutionary Dynamics of Neoplastic Cells: Simulating Benign Cell Boosters and Selection for Chemosensitivity
Authors: Maley Carlo C. , Reid Brian J. , Forrest Stephanie
Published: June 2022

Cells in neoplasms evolve by natural selection. Traditional cytotoxic chemotherapies add further selection pressure to the evolution of neoplastic cells, thereby selecting for cells resistant to the therapies. An alternative proposal is a benign cell booster. Rather than trying to kill the highly dysplastic or malignant cells directly, a benign cell booster increases the fitness of the more benign cells, which may be either normal or benign clones, so that they may outcompete more advanced or malignant cells in a neoplasm. In silico simulations of benign cell boosters in neoplasms with evolving clones show benign cell boosters to be effective at destroying advanced or malignant cells and preventing relapse even when applied late in progression. These results are conditional on the benign cell boosters giving a competitive advantage to the benign cells in the neoplasm. Furthermore, the benign cell boosters must be applied over a long period of time in order for the benign cells to drive the dysplastic cells to extinction or near extinction. Most importantly, benign cell boosters based on this strategy must target a characteristic of the benign cells that is causally related to the benign state to avoid relapse. Another promising strategy is to boost cells that are sensitive to a cytotoxin, thereby selecting for chemosensitive cells, and then apply the toxin. Effective therapeutic and prevention strategies will have to alter the competitive dynamics of a neoplasm to counter progression toward invasion, metastasis, and death.
The CYP19 Gene Codon 39 Trp/Arg Polymorphism Increases Breast Cancer Risk in Subsets of Premenopausal Japanese
Authors: Hirose Kaoru , Matsuo Keitaro , Toyama Tatsuya , Iwata Hiroji , Hamajima Nobuyuki , Tajima Kazuo
Published: June 2022

The production of estrogen from androgen via the estrogen biosynthesis pathway is catalyzed by aromatase P450 (CYP19). To assess the association between breast cancer risk and a polymorphism at codon 39 Trp/Arg of the encoding gene, a case-control study was conducted at Aichi Cancer Center Hospital in Japan. Subjects were 248 histologically confirmed breast cancer patients and 603 hospital controls without cancer. Odds ratios (OR) and 95% confidence intervals (95% CI) were determined by logistic regression analysis. The allele frequency among controls was 3.8% for the C allele, and the OR (95% CI) of the polymorphism relative to TT genotype was 1.21 (0.69-2.14) for TC/CC genotypes combined. There was no association between CYP19 gene polymorphism and breast cancer risk in the study group as a whole, but homozygous and heterozygous carriers of the variant Arg allele showed a significantly increased risk of breast cancer among premenopausal women with a late age at first full-term pregnancy (OR 7.31, 95% CI 1.88-28.5) or a high body mass index (OR 2.77, 95% CI 1.12-6.87). Additional larger studies should be done to confirm that the rare CYP19 variant increases the risk of breast cancer among premenopausal Japanese women.
Fruits, Vegetables, and Micronutrients in Relation to Breast Cancer Modified by Menopause and Hormone Receptor Status
Authors: Gaudet Mia M. , Britton Julie A. , Kabat Geoffrey C. , Steck-Scott Susan , Eng Sybil M. , Teitelbaum Susan L. , Terry Mary Beth , Neugut Alfred I. , Gammon Marilie D.
Published: June 2022

Whether fruit, vegetable, and antioxidant micronutrient consumption is associated with a reduction in breast cancer incidence remains unresolved. To address this issue, we analyzed data from a large population-based case-control study, with consideration given to whether the associations varied with menopausal status or with clinical characteristics of the cases' disease. Study participants completed a modified Block food frequency questionnaire, which included assessment of the frequency and portion sizes of 13 fruits and fruit juices and 16 vegetables and the use of multiple and single vitamin supplements. Statistical analyses were done on 1,463 cases and 1,500 controls. Among postmenopausal women, reduced odds ratios [OR; 95% confidence intervals (95% CI)] were noted for the highest fifth, as compared with the lowest fifth, of intake of any vegetables [0.63 (0.46–0.86); P for trend < 0.01] and leafy vegetables [0.66 (0.50–0.86); P for trend = 0.03] after controlling for age and energy intake. Adjusted ORs (95% CIs) were also decreased for postmenopausal breast cancer in relation to high intake of carotenoids, α-carotene, β-carotene, lutein, and particularly lycopene [0.66 (0.48–0.90); P for trend = 0.03]. Inverse associations for fruits and vegetables were stronger for postmenopausal women with estrogen receptor (ER)+ tumors (OR, 0.65; 95% CI, 0.51–0.82) than ER− tumors (OR, 0.92; 95% CI, 0.64–1.32), but results were less consistent for micronutrients. No similarly reduced associations were observed among premenopausal women. ORs did not appreciably differ by in situ or invasive breast cancer or by whether cases had begun chemotherapy. Our results support an inverse association for fruit and vegetable intake among postmenopausal but not premenopausal breast cancer, which may be more pronounced among women with ER+ tumors.