Normal Population Research Articles

3-Dimensional quantitative analysis of mandibular motion in TMD and healthy subjects: Comparison with clinical observations.

To establish a quantitative method for objectively assessing 3-dimensional (3D) mandibular trajectories and comparing clinical evaluations with computational analyses. In total, 184 volunteers were recruited and grouped into control (n = 121) and temporomandibular disorder (TMD) groups (n = 63) according to the dual-axis DC/TMD checklist. 3D trajectories were generated by integrating mandibular motion and cone beam computed tomography (CBCT) records. Via digitalized data processing, the following 3 outcomes were assessed: (1) smoothness using the best-fitting polynomial curve, (2) open-closure separation by measuring the deviation between open-closure phases, and (3) condylar trajectory symmetry by comparing left and right movements. Intraclass Correlation Coefficients (ICC) were used to determine agreement between expert observations and quantitative results. Reference ranges for each parameter from the normal population were calculated. Mann‒Whitney test was used to analyze the features of the trajectories between the two groups. ICC confirmed strong consistency between the parametric variations and expert observations (smoothness: 0.797; open-closure separation: 0.820; left-right symmetry: 0.920). Quantitative analyses revealed significant differences (P < 0.043 for smoothness, P < 0.01 for separation, and P = 0.012 for symmetry) in all comparisons between movement trajectories of normal participants and those with TMD, with the latter group exhibiting greater variation and irregularities. The normal range of smoothness was calculated for condylar trajectories between 0 and 0.25 and 0-0.10 for incisal point trajectories. Open-closure separation normal range was computed between 0 and 2.28 mm for incisal point trajectory, 0-1.90 mm for left condylar trajectory, and 0-1.76 mm for right condylar trajectory. The normal range of symmetry between condylar trajectories was calculated to be between 0 and 4.21 mm. This quantitative analysis was confirmed to be reliable and consistent with expert observations. This allowed for the discovery of substantially quantified differences in smoothness, open-closure separation, and symmetry of the motion trajectories in TMD patients versus controls.

The Congenitally Malformed Aortic Valve in Type A Aortic Dissection: Its Frequency and Consequences

A congenitally malformed aortic valve, unicuspid (UAV) or bicuspid (BAV), occurs in about 1% of the population and is known to be more frequent in patients with aortic dissection. The clinical and operative findings in a series of 134 patients with spontaneous, acute Type A aortic dissection (TAAD) were studied, comparing patients with normal and abnormal aortic valve morphology. The aortic valve was normal in 123/134 (92%) patients and abnormal in 11/134 (8%) patients: BAV in 10/134 (7.5%) and UAV in 1/134 (0.7%). Demographics were similar between groups except for a lower frequency of systemic hypertension in the UAV/BAV group (46 vs. 82%, p<0.01). Penn class stratification was also similar in the 2 groups. The UAV/BAV group had a greater frequency of aortic root enlargement (64 vs. 18%, p<0.01) and a larger median root diameter (5.7 vs. 4.6cm, p=0.02). In the UAV/BAV group, the entry tear was more frequently in proximal (intrapericardial) zone 0 (91 vs. 62%, p=0.049). The frequency of abnormal aortic media histology was similar. The rate of root replacement was higher in the UAV/BAV group and early mortality was similar. The frequency of congenitally malformed aortic valve in this series was 8x the normal population. The one UAV in the series was the only severely stenotic valve. In TAAD patients with a congenitally malformed valve, aortic root aneurysm was more common and the entry tear was nearly always proximal.

Change in Grading of Stunting in Children aged 0-5 years in a Tertiary Hospital in Western India by Using WHO vs. Indian References.

To classify under 5-y-old children into normal, short, severe short and tall categories as per WHO (2006) and Indian 2019 synthetic growth charts and to compare the change in the proportion of stunted children based on these two charts. This study was done on 1557 (795 boys) apparently healthy children of age group 0-5 y who attended outpatient clinics for routine vaccination and their stature categories were compared on WHO 2006 vs. 2019 Indian synthetic charts. Children were categorized into severe short, short, normal and tall on both charts by calculating z scores. On WHO charts 73.5% children were classified as normal vs. 85.4% on 2019 Indian synthetic charts. The mean Z score for height for age as per WHO was -0.85 (+/-1.62), whereas as for 2019 synthetic charts was -0.37 (+/-1.38). While using WHO growth charts the prevalence of short stature was 15.03%, and severe short stature was 7.51%, which dropped to 7.77% for short stature and 2.38% for severe short stature on 2019 synthetic charts, respectively. WHO Growth charts overdiagnose short stature by 12.4% (WHO 22.54% vs. Indian synthetic 10.15%) in an apparently normal population of under five children. Use of regional growth charts may reduce the need to unnecessarily investigate normal children.

Proximal humerus fracture dislocations: outcomes of management.

Proximal humerus fracture dislocations are amongst the most severe proximal humerus injuries, presenting a challenging management problem. The aim of this study was to report on long-term outcomes of management of proximal humerus fracture dislocations. Patients with a proximal humerus fracture dislocation managed at a Level 1 trauma centre from January 2010 to December 2018 were included. Patients with isolated tuberosity fracture dislocations or pathological fractures were excluded. Outcome measures were the Oxford Shoulder Score (OSS), EQ-5D-5L, return to work and radiological outcomes. Complications recorded included further surgery, loss of position/fixation, non-union/malunion and avascular necrosis. Sixty-nine patients were included with a proximal humerus fracture dislocation in the study period; 48 underwent surgical management and 21 were managed successfully with closed reduction alone. The mean (SD) age of the cohort was 59.7 (±20.4), and 54% were male. Overall patients reported a mean OSS of 39.8 (±10.3), a mean EQ-5D utility score of 0.73 (±0.20), and 78% were able to return to work at a median of 1.2 months. There was a high prevalence of complications in both patients managed operatively or with closed reduction (25% and 38% respectively). In patients undergoing surgical management, 21% required subsequent surgery. Patient reported outcome measures post proximal humerus fracture dislocations do not return to normal population levels. Further, these injuries are associated with a high prevalence of complications. Appropriate patient counselling should be undertaken before embarking on definitive management.

To assess the Vaccination status Against Hepatitis B among Medical, Dental students and HCWs in Isra University

Background/objective: hepatitis b virus (HBV) is a blood borne virus responsible for potentially life-threatening liver infection and a major hazard for healthcare workers (HCWS). HCWS should have proper knowledge regarding risks and transmission of HBV as they are at higher risk than normal population. This study was created to evaluate attitude and status of HBV vaccination and re-immunization among hcws. Methods: in this cross-sectional study, we assessed hepatitis b vaccination status among 300 medical and dental students, and healthcare workers (HCWS) at isra university hospital. Utilizing stratified random sampling ensured representation across diverse healthcare professionals. Survey forms, both electronic and printed, collected data on demographics, vaccination status, booster dose awareness and status, and antibody titer testing. Data analysis using SPSS v25 employed descriptive and inferential statistics to illuminate vaccination trends and potential demographic associations. Ethical considerations, including informed consent and confidentiality protocols, were rigorously followed under irb approval from Isra university. Results: out of 297 participants included in this study 177 (59.6%) were vaccinated against HBV with the highest frequency seen in doctors (28.3%). Of the vaccinated HCWS, 51 (17.2%) had received a booster dose and out of all the participants, 63 (21.2%) had their antibody levels (titres) checked. Conclusion: A significant proportion of HCWS is fully vaccinated. Given that a substantial fraction of HCWS were not adequately protected and educated, more aggressive awareness campaigns, regulations, and universal screening should be required of HCWS. This includes administering a booster dose and determining anti-HBS titer levels.

Mathematical Optimization of Monte Carlo Simulation Parameters for Predicting Stock Prices

Stock price prediction holds paramount significance for individual investors, guiding crucial decisions in financial planning and investment strategies. This research delves into the methodology of Monte Carlo simulation, a versatile tool in financial modeling, to assess its advantages and disadvantages in the context of predicting stock prices. The study employs Python code to demonstrate the step-by-step implementation of Monte Carlo simulations, emphasizing the mathematical optimization of parameters for enhanced accuracy. Results showcase a characteristic bell curve, offering a probabilistic perspective on potential outcomes. Comparative analyses with other forecasting models, such as graphic analysis, underscore the superior reliability of Monte Carlo simulation in evaluating risks and rewards. Furthermore, the paper explores the application of Monte Carlo simulation in real-world scenarios, such as portfolio optimization and retirement planning, highlighting its pragmatic value for individual investors navigating the complexities of the stock market. The research concludes by acknowledging the limitations of the approach and advocating for a comprehensive consideration of all relevant factors in financial decision-making. This exploration serves as a valuable resource for individual investors seeking informed insights into probabilistic forecasting methods for effective stock price predictions.

Self-supervised learning of scale-invariant neural representations of space and time.

Hippocampal representations of space and time seem to share a common coding scheme characterized by neurons with bell-shaped tuning curves called place and time cells. The properties of the tuning curves are consistent with Weber's law, such that, in the absence of visual inputs, width scales with the peak time for time cells and with distance for place cells. Building on earlier computational work, we examined how neurons with such properties can emerge through self-supervised learning. We found that a network based on autoencoders can, given a particular inputs and connectivity constraints, produce scale-invariant time cells. When the animal's velocity modulates the decay rate of the leaky integrators, the same network gives rise to scale-invariant place cells. Importantly, this is not the case when velocity is fed as a direct input to the leaky integrators, implying that weight modulation by velocity might be critical for developing scale-invariant spatial receptive fields. Finally, we demonstrated that after training, scale-invariant place cells emerge in environments larger than those used during training. Taken together, these findings bring us closer to understanding the emergence of neurons with bell-shaped tuning curves in the hippocampus and highlight the critical role of velocity modulation in the formation of scale-invariant place cells.

Radiological Evaluation of the Proximal Femoral Geometric Parameters of Adult Bangladeshi Population

Background: The present study is aimed to determine the value of proximal femoral parameters such as Femoral Neck Shaft Angle (FNSA) Femoral Neck Length (FNL) and Femoral Neck Width (FNW) of both sexes and also on both sides for the purpose of adequate planning, preparation and pre-operative selection of prosthetic implants and also stocking of prosthesis implants in hospitals located in developing countries like Bangladesh. Materials and methods: It was a cross sectional observational study and was conducted by Department of Anatomy, Chittagong Medical College from July 2020 to June 2021 among 200 (119 male, 81 female) normal adult Bangladeshi population of Chattogram district. Normal participants, both male and female were recruited from Radiology Department of Chittagong Medical College Hospital (CMCH) as per enrolment criteria. After taking demographic data of all participants plain pelvic X-ray A/P view were taken and reported by an expert radiologist of CMCH. Only normal radiographs were included in the study. All measurements such as FNSA, FNL and FNW of femur were taken from both sides of the X-rays. Data were analyzed by SPSS version–25. Results: In this study, mean FNSA, FNW and FNL were found larger in male than in female. The FNSA, FNW and FNL all were found higher in right side than the left and also statistically significant. Conclusion: The result of the present study provides some baseline information about proximal femoral parameters of adult Bangladeshi population which will help to design the prosthesis for hip replacement. Chatt Maa Shi Hosp Med Coll J; Vol.23 (1); January 2024; Page 9-13

Normal Residual Lymphoid Cell Populations in Blood as Surrogate Biomarker of the Leukemia Cell Kinetics in CLL BinetA/Rai 0

Background/Objectives: Despite the current international prognostic index for chronic lymphocytic leukemia (CLL) being widely accepted and broadly used, it does not consider the kinetics of the B-cell clone over time. Here, we investigated the potential association between distinct features of leukemic cells and other immune cells in blood and the kinetics of clonal B-cells in CLL stage Binet A/Rai 0 (A/0) patients; Methods: Based on the leukemia cell kinetics, 69 CLL A/0 cases followed for a median of 105 months were classified as carrying stable (n = 53) vs. rapidly increasing in size (n = 16) CLL clones; Results: Patients with increasing CLL clones had a significantly higher risk of disease progression and shortened time to first therapy vs. those carrying stable B-cell clones (p ≤ 0.001). Strikingly, the distribution of various immune-cell populations in blood at diagnosis also differed significantly between the two groups, with lower Tαβ CD4+CD8lo cell counts (p = 0.03), a greater switched/unswitched memory B-cell ratio (p = 0.01), and higher plasma cell counts (p = 0.05) in CLL with increasing vs. stable clones. Multivariate analysis revealed that the number of circulating clonal B-cells (≥15 × 109/L) and Tαβ CD4+CD8lo cells (≤35 cells/µL), together with an IGHV unmutated gene status at diagnosis, were independent predictors of an increasing CLL clone; Conclusions: Altogether, these data suggest that the expansion of the CLL clone in stage A/0 patients may depend on both the intrinsic characteristics of CLL cells and the surrounding immune microenvironment.

Exploring the performance of large language models on hepatitis B infection-related questions: A comparative study.

Patients with hepatitis B virus (HBV) infection require chronic and personalized care to improve outcomes. Large language models (LLMs) can potentially provide medical information for patients. To examine the performance of three LLMs, ChatGPT-3.5, ChatGPT-4.0, and Google Gemini, in answering HBV-related questions. LLMs' responses to HBV-related questions were independently graded by two medical professionals using a four-point accuracy scale, and disagreements were resolved by a third reviewer. Each question was run three times using three LLMs. Readability was assessed via the Gunning Fog index and Flesch-Kincaid grade level. Overall, all three LLM chatbots achieved high average accuracy scores for subjective questions (ChatGPT-3.5: 3.50; ChatGPT-4.0: 3.69; Google Gemini: 3.53, out of a maximum score of 4). With respect to objective questions, ChatGPT-4.0 achieved an 80.8% accuracy rate, compared with 62.9% for ChatGPT-3.5 and 73.1% for Google Gemini. Across the six domains, ChatGPT-4.0 performed better in terms of diagnosis, whereas Google Gemini demonstrated excellent clinical manifestations. Notably, in the readability analysis, the mean Gunning Fog index and Flesch-Kincaid grade level scores of the three LLM chatbots were significantly higher than the standard level eight, far exceeding the reading level of the normal population. Our results highlight the potential of LLMs, especially ChatGPT-4.0, for delivering responses to HBV-related questions. LLMs may be an adjunctive informational tool for patients and physicians to improve outcomes. Nevertheless, current LLMs should not replace personalized treatment recommendations from physicians in the management of HBV infection.

Long-Term Risk of Inflammatory Bowel Disease With MASLD: A Large-Scale Prospective Cohort Study in UK Biobank.

Similar worsening epidemics globally have been showed in newly coined metabolic dysfunction-associated steatotic liver disease (MASLD) and inflammatory bowel disease (IBD). We aimed to investigate the prospective association of MASLD, MASLD types, and cardiometabolic risk factors (CMRFs) with long-term risk of incident IBD in a large-scale population cohort. Participants free of IBD at enrollment from UK Biobank were included. Baseline MASLD was measured by fatty liver index together with at least one CMRF, based on the latest AASLD/EASL criteria. MASLD type was classified as pure MASLD and MetALD (MASLD with increased alcohol intake). Primary outcome was incident IBD, including ulcerative colitis (UC) and Crohn's disease (CD). Multivariable Cox regression was conducted to examine the related associations. Overall, 403 520 participants (aged 56.2 ± 8.1 years, 45.6% males) were included. Of whom, 151 578 (37.6%) were considered as MASLD at baseline. During a median of 13.0 years' follow-up, 2398 IBD cases were identified. Compared with normal population, individuals with MASLD showed significant higher associations of incident IBD (HR = 1.39, 95% CI: 1.21-1.60), UC (HR = 1.34, 95% CI: 1.13-1.58), and CD (HR = 1.51, 95% CI: 1.20-1.89). Meanwhile, results were consistent when assessing pure MASLD (HR = 1.43, 95% CI: 1.23-1.66) and MetALD (HR = 1.46, 95% CI: 1.15-1.86). The excess risk of incident IBD was more evident with the increase of CMRFs numbers (ptrend < 0.001). MASLD, either pure MASLD or MetALD, and a combination of different CMRFs are all associated with increased risk of IBD, including both UC and CD. Additionally, there is greater risk of incident IBD as the number of CMRFs increase.

Systemic Mechanisms of Ionic Regulation in Carcinogenesis.

Cancer is a complex disease characterized by uncontrolled cell proliferation at various levels, leading to tumor growth and spread. This review focuses on the role of ion homeostasis in cancer progression. It describes a model of ion-mediated regulation in both normal and cancerous cell proliferation. The main function of this system is to maintain the optimal number of cells in the body by regulating intra- and extracellular ion content. The review discusses the key points of ion regulation and their impact on tumor growth and spread during cancer development. It explains that normal levels of sodium, potassium, calcium, chloride, and hydrogen ions are regulated at different levels. Damage to ion transport mechanisms during carcinogenesis can lead to an increase in sodium cations and water content in cells, disrupting the balance of calcium and hydrogen ions. This, in turn, can lead to chromatin compaction reduction, gene overexpression, and instability at the epigenetic and genomic levels, resulting in increased cell proliferation and mutagenesis. Restoring normal ion balance can reduce the proliferative potential of both normal and tumor cell populations. The proposed model of systemic ionic regulation of proliferation aims to reconcile diverse data related to cell mitotic activity in various physiological conditions and explain tumor growth. Understanding the mechanisms behind pathological cell proliferation is important for developing new approaches to control ion homeostasis in the body, potentially leading to more effective cancer treatment and prevention.

Results on Enhanced Continuous Random Variable’s Probability Distribution Using a Different Exponential Function for the Normal Probability Distribution

In the history of probability and statistics, general normal probability has played an important role. I utilize a different exponential function to create a new continuous probability density function akin to the Laplace Gauss distribution function. Finding an alternate probability distribution is required so that the probability can be determined without referring to the table data. I noticed that the findings are pretty comparable to the normal probability distribution values. I checked the new results against a few standard cases. The advantage of this exponential function is that we can calculate the probability of a z value with more than two decimals, whereas with a normal distribution, we can only use z values with two decimals.

Complex-valued three-dimensional atomic spectroscopy with Gaussian-assisted inline holography

When a laser-cooled atomic sample is optically excited, the envelope of coherent forward scattering can often be decomposed into a few complex Gaussian profiles. The convenience of Gaussian propagation helps address key challenges in digital holography. In this paper, we develop a Gaussian-decomposition-assisted approach to inline holography for single-shot, simultaneous measurements of absorption and phase-shift profiles of small atomic samples sparsely distributed in three dimensions. The samples' axial positions are resolved with micrometer resolution and their spectroscopy are extracted from complex-valued images recorded at various probe frequencies. The phase-angle readout is not only robust against transition saturation but also insensitive to atom-number and optical-pumping-induced interaction-strength fluctuations. Benefiting from such features, we achieve hundred-kHz-level single-shot resolution to the transition frequency of a Rb87 D2 line, with merely hundreds of atoms. We further demonstrate single-shot three-dimensional field sensing by measuring local light shifts to the atomic array with micrometer spatial resolution. Published by the American Physical Society 2025

Explicit travelling wave solutions to the time fractional Phi-four equation and their applications in mathematical physics

In applied research, fractional calculus plays an important role for comprehending a wide range of intricate physical phenomena. One of the Klein-Gordon model’s peculiar case yields the Phi-four equation. Additionally, throughout the past few decades it has been utilized to explain the kink and anti-kink solitary waveform contacts that occur in biological systems and in the field of nuclear mechanics. In this current work, the key objective is to analyze the consequences of fractional variables on the soliton wave dynamic behavior in a nonlinear time-fractional Phi-four equation. Using the formulation of the conformable fractional derivative it illustrates some of the recovered solutions and analyze their dynamic behavior. The analytical solutions are drawn by using the extended direct algebraic and the Bernoulli Sub-ODE scheme. Various types of soliton solutions are proficiently expressed. Adjusting the specific values of fractional parameters allows to produce the periodic, kink, bell shape, anti-bell shape and W-shaped solitons. The impact of the conformable derivative on the precise solutions of the fractional Phi-four equation is demonstrated with a series of 2D, 3D and contour graphical representations.

Prevalence of neoplasms in acromegaly: a Turkish single-center retrospective study

Aims: This study aimed to investigate the prevalence of benign and malignant neoplasms and to assess associated clinical conditions in patients with acromegaly. Methods: In this single center, retrospective and observational study, data from 71 patients with acromegaly followed at an endocrinology and metabolism diseases outpatient clinic between January 2010 and December 2023 were reviewed through the hospital's electronic database. Patients' medical histories, demographic data, blood examinations, medications, pituitary MRI scans, thyroid ultrasound, mammography, colonoscopy, endoscopy, and pathology reports were evaluated. Acromegaly diagnosis was based on elevated insulin-like growth factor-1 (IGF-1) levels and unsuppressed growth hormone (GH) levels after oral glucose tolerance testing. The chi-square test and Mann-Whitney U test were used to compare patients with malignancy to other patients in terms of demographic and clinical characteristics. Results: The study included predominantly female patients (60.6%) with an average age of 55.6 years. The mean age at diagnosis was 44.3±11.3 years, and the mean disease duration was 11.3±8.4 years. Malignancies, including breast, thyroid, and colorectal cancers, were detected in 9.9% of patients. Additionally, thyroid nodules were present in 62% of patients, and colon polyps in 14.1%. No significant differences were observed in clinical features including age, gender, disease duration, GH levels, IGF-1 levels, adenoma size, or remission frequency between patients with and without malignancy (p&gt;0.05 for all). Conclusion: This study reveals an increased prevalence of breast, colon, and thyroid cancers in patients with acromegaly. Performing cancer screenings in patients with acromegaly more comprehensively and at an earlier stage compared to the normal population may be beneficial.

The Impact of Embryo Donation Technology on Child Psychological Adjustment and parenting styles: A Comparative Study.

Despite the remarkable advancements in the use of embryo donation, concerns have arisen regarding its potential effects on the psychological well-being of children conceived through this assisted reproductive technology and their parent-child relationships. The aim of the study is to evaluate children's psychological adjustment and parenting style in families with donor-conceived children and compare them with the normal population. A historical cohort study was conducted to assess the psychological adjustment of 31 children aged 3 to 7 years born via embryo donation and to compare the results with those of 30 age-matched children from families who conceived naturally using the Strengths and Difficulties Questionnaire. The sample size was determined using G power, and the samples were selected using a convenient sampling method. Parenting styles within these families were also evaluated using the Baumrind Parenting Styles Inventory through clinical interviews. Although 8 out of 31 children born through embryo donation (25.8%) and 3 out of 30 children from families with natural conception exhibited psychological maladjustment, this difference was not statistically significant (P=0.249). Furthermore, there were no significant differences in parenting styles between the two groups (P values for permissive, authoritarian, and authoritative parenting styles were 0.424, 0.656, and 0.219, respectively). The lack of genetic parent-child relationships does not seem to be a dominant factor affecting the psychological adjustment of children or parenting styles.

Ad-plot and Ud-plot for determining distributional characteristics and normality

. The histogram and boxplot are broadly used to visualize distributional characteristics of the data such as symmetry, skewness, and outliers. Sv-plot1, Sv-plot2, and Sv-plot3 can also detect these attributes, and remarkably, Sv-plot2 and Sv-plot3 are employable in testing hypotheses. Meanwhile, normal QQ-plot and normal PP-plot are leading tools for assessing normality. Herein two statistical plots, Ad-plot and Ud-plot are innovated by investigating a novel functional estimator that is formed by cumulatively averaging the deviations of the data below a target value. The Ad-plot can depict symmetry, skewness, and outliers of the distribution as histogram and Sv-plot2 reveal. Concurrently, the Ud-plot derived from a slight modification of the estimator by proving a theorem helps visualize normality analogous to normal QQ- and PP-plots. The d-value is introduced by quantifying the degree of proximity of the Ud-plot to the graph of the estimated normal probability density function. Ud-plot accompanied by the desirable normal curve greatly enhances the perception on checking normality. The simulated and real data strongly agree with the Ad-plot for identifying central distributional characteristics competing with Sv-plot2 and histogram. Exceptionally, the Ud-plot is prominent in assessing normality by delivering an informative value-added data visualization, outperforming both normal QQ-plot and normal PP-plot.

Numerical investigation of the influence of pulse frequency on the weld pool size in pulsed current TIG welding

This study simulates the pulsed current tungsten inert gas (TIG) welding process to investigate the transient development of the weld pool in a 4 mm thick aluminum sheet, focusing on the effects of pulse frequency on the weld pool size. Two pulsed currents, 230 and 180 A, with a 30% background current, were examined. The 230 A current achieved full, while the 180 A resulted in partial penetration. Five pulse frequencies (1, 4, 10, 20, and 50 Hz) were analyzed. A numerical model was developed to compute heat and current fluxes on the workpiece surface. The arc profile shifted from a bell shape in high-frequency cycles to a conical shape in low-frequency cycles. The heat and current fluxes served as inputs to another model that simulated weld pool behavior for both direct and pulsed current TIG welding. The results showed that weld pool size decreased in pulsed current TIG welding. At 230 A, full penetration changed to partial penetration under pulsed current. At 1 Hz, sufficient time was available for solidification during the low-cycle period, but at 50 Hz, the weld pool remained liquid. As pulse frequency increased from 1 to 50 Hz, the weld pool depth decreased significantly, with a reduction from 2.4 to 0.9 mm at 230 A and from 1.1 to 0.34 mm at 180 A. Convection in the weld pool was influenced by temperature and was strongest at higher temperatures. The decrease in weld pool size was most pronounced between 1 and 10 Hz, stabilizing between 20 and 50 Hz. Validation against experimental macrographs demonstrated good agreement with the simulations.

The Naked Neurosurgeon and the Anatomy of a Complication.

IntroductionThe neurosurgeon is always poised precariously between the operation and the abyss of a complication. As Wilder Penfield sagaciously wrote in 1961, "I will faithfully record and analyze my failures in the care of the sick, seeking the cause, so that those who follow may be warned of the danger."AimThis paper seeks to briefly overview the literature on complications in surgery, neurosurgery in particular.Materials and MethodProgress in our specialty has been accomplished by the overcoming of complications via technique or technology. Dr. Samer Nashef commented sarcastically that surgeons are not, as a general rule, well known for their rapacious appetite for reading. But knowing the literature on complications from our field and others is essential for progress. We must know the anatomy of complications to avoid and manage them.In 1992, Michael Apuzzo published his magnus opus, Brain surgery: Complication avoidance and management, which was admirably followed by Edward Benzel's edited work Spine surgery: Techniques, complication avoidance and management, setting standards in the science of complication avoidance and management in 1999 for years to come. In 2001, Crossing the quality chasm: A new health system for the twenty-first century was published in the United States by the Institute of Medicine. Lucian Leape (a pediatric and thoracic surgeon) published Error in Medicine in JAMA in December 1994, and in 1991, he published the Harvard Medical Practice Study, defining essential terms like adverse event and negligence. Atul Gawande, a general surgeon at Harvard University, wrote "The Bell Curve: What happens when patients find out how good their doctors really are," in the New Yorker on December 6, 2004; he went on to pen Complications-A surgeon's notes on an imperfect science in 2002 and Better: A surgeon's notes on performance in 2007; and he peaked with his classic The Checklist Manifesto-How to get things right in 2009. In 2015, The Naked Surgeon-The power and peril of transparency in medicine appeared. Written by a cardiothoracic surgeon, Samer Nashef, the book takes the study of complication avoidance to a different level and describes how cardiac surgery blazed the trail in quality monitoring and improvement, leaving no scope for other specialties but to follow. The era of the naked neurosurgeon may be beginning anytime.ConclusionEver since E. C. Pearce delivered the 34th Rovenstine lecture, 40years behind the mask-Safety revisited, in 1996, the literature on complication avoidance and management has been growing exponentially. Cross-specialty discourse and the exchange of ideas are essential for neurosurgery to maintain its position as the emperor of all specialties.