Global change progressively increases foliar nitrogen-phosphorus ratios in China's subtropical forests.

Globally increased nitrogen (N) to phosphorus (P) ratios (N/P) affect the structure and functioning of terrestrial ecosystems, but few studies have addressed the variation of foliar N/P over time in subtropical forests. Foliar N/P indicates N versus P limitation in terrestrial ecosystems. Quantifying long-term dynamics of foliar N/P and their potential drivers is crucial for predicting nutrient status and functioning in forest ecosystems under global change. We detected temporal trends of foliar N/P, quantitatively estimated their potential drivers and their interaction between plant types (evergreen vs. deciduous and trees vs. shrubs), using 1811 herbarium specimens of 12 widely distributed species collected during 1920-2010 across China's subtropical forests. We found significant decreases in foliar P concentrations (23.1%) and increases in foliar N/P (21.2%). Foliar N/P increased more in evergreen species (22.9%) than in deciduous species (16.9%). Changes in atmospheric CO2 concentrations ( P CO 2 $$ {\mathrm{P}}_{{\mathrm{CO}}_2} $$ ), atmospheric N deposition and mean annual temperature (MAT) dominantly contributed to the increased foliar N/P of evergreen species, while P CO 2 $$ {\mathrm{P}}_{{\mathrm{CO}}_2} $$ , MAT, and vapor pressure deficit, to that of deciduous species. Under future Shared Socioeconomic Pathway (SSP) scenarios, increasing MAT and P CO 2 $$ {\mathrm{P}}_{{\mathrm{CO}}_2} $$ would continuously increase more foliar N/P in deciduous species than in evergreen species, with more 12.9%, 17.7%, and 19.4% versus 6.1%, 7.9%, and 8.9% of magnitudes under the scenarios of SSP1-2.6, SSP3-7.0, and SSP5-8.5, respectively. The results suggest that global change has intensified and will progressively aggravate N-P imbalance, further altering community composition and ecosystem functioning of subtropical forests.

Auto-setting multi-soliton temporal spacing in a fiber laser by a hybrid GA-PSO algorithm.

Multi-soliton operation in fiber lasers is a promising platform for the investigation of soliton interaction dynamics and high repetition-rate pulse. However, owing to the complex interaction process, precisely manipulating the temporal spacing of multiple solitons in a fiber laser is still challenging. Herein, we propose an automatic way to control the temporal spacing of multi-soliton operation in an ultrafast fiber laser by a hybrid genetic algorithm-particle swarm optimization (GA-PSO) algorithm. Relying on the intelligent adjustment of the electronic polarization controller (EPC), the on-demand temporal spacing of the double solitons can be effectively achieved. In particular, the harmonic mode locking with equal temporal spacing of double solitons is also obtained. Our approach provides a promising way to explore nonlinear soliton dynamics in optical systems and optimize the performance of ultrafast fiber lasers.

Assisting the mode-locking of a figure-9 fiber laser by thermal nonlinearity of graphene-decorated microfiber.

The self-starting performance of a figure-9 fiber laser is critically dependent on the phase shift difference between the counter-propagating beams. Herein, we propose an effective approach to dynamically control the phase shift difference in a figure-9 fiber laser by utilizing the thermal nonlinearity of graphene-decorated microfiber device. With the adjustment of the control laser power injected into the graphene-decorated microfiber, the self-starting mode-locked threshold of the figure-9 fiber laser can be attained in a flexible pump power range, i.e., from 300 mW to 390 mW. These findings demonstrated that the graphene-decorated microfiber could act as a dynamical control device of phase shift difference for improving the performance of figure-9 fiber lasers, and might also open up new possibilities for applications of microfiber photonic devices in the field of ultrafast optics.

Mechanisms and rules of social learning in crickets.

A new study on insect social learning shows that crickets learn to prefer a rewarded odorant by observing the choice of a conspecific and without experiencing the reward themselves. The mere perception of the conspecific activates octopaminergic reward neurons in the brain of the observer, thus facilitating odorant learning.

Association between axial length and HDL in children: a hospital-based cross-sectional study.

BACKGROUND: To analyze the relationship between axial length and levels of high-density lipoprotein (HDL) cholesterol in children. METHODS: A retrospective, hospital-based cross-sectional research with 69 right eyes from 69 children who underwent health examination by Zhejiang Provincial People's Hospital was carried out. The participants were split into three groups: Group A (axial length < = 23 mm), Group B (axial length 23-24 mm), and Group C (axial length > 24 mm). Demographic epidemiological information, blood biochemical parameters and ophthalmic characteristics including refractive status and ocular geometric parameters were obtained and analyzed. RESULTS: 69 right eyes from 69 patients (25 males and 44 females) with a median age of 10.00 years old (IQR: 8.00-11.00 years) were included in the study. Within Group A, there were a total of 17 individuals; Group B consisted of 22 individuals; Group C included 30 individuals. The mean axial length of three groups was 22.148(0.360), 23.503(0.342) and 24.770(0.556) mm, respectively (p < 0.0001). The mean HDL levels were significantly different in three groups are 1.824(0.307), 1.485(0.253) and 1.507 (0.265) mmol/L, respectively. By applying a Pearson Coefficient, we evaluated the association between axial length and HDL and discovered that there was a statistically significant (p = 0.00025) and adverse (R = -0.43) association between axial length and HDL. CONCLUSIONS: We concluded from our study that there was a significantly inverse relationship between axial length and the levels of HDL in children.

Comparison of Aurolab Aqueous Drainage Implant with Ahmed Glaucoma Valve for Refractory Glaucoma: A Meta-Analysis.

BACKGROUND: Ahmed glaucoma valve (AGV) is a common surgical method for the treatment of refractory glaucoma.Aurolab aqueous drainage implant (AADI) is a novel surgical method which has been applied in clinical practice in recent years. OBJECTIVE: The purpose of this study was to compare the efficacy and safety of the AADI and the AGV for the treatment of refractory glaucoma. METHODS: We comprehensively searched four databases, including PubMed, Embase, Web of Science, and the Cochrane Library databases, selecting the relevant studies. The continuous variables, namely, intraocular pressure reduction (IOPR) and a reduction in antiglaucoma medication (AGMR), were pooled by the weighted mean differences (WMDs), and the dichotomous outcomes, including success rates and complications, were pooled by the odds ratio (OR). RESULTS: A total of 825 eyes from 820 patients from six studies were included. The WMDs of the IOPR between the AADI and the AGV implant were 0.58 (95% CI: 0.07-1.09) at 3 months, 0.44 (95% CI: 0.11-0.77) at 6 months, 2.20 (95% CI: 0.63-3.77) at 12 months, and 3.24 (95% CI: 1.73-4.75) at follow-up endpoint. Significant difference was detected between the two groups at any point in time. The WMDs of the AGMR between the AADI and the AGV implant were 0.87 (95% CI: 0.61-1.13) at 6 months, 1.04 (95% CI: 0.66-1.42) at 12 months, and 0.93 (95% CI: 0.52-1.34) at the follow-up endpoint; the differences reached statistical significance at any point in time. The pooled ORs comparing the AADI with the AGV were 3.64 (95% CI: 2.44-5.45) for the complete success rate and 1.72 (95% CI: 1.24-2.39) for qualified success rate; significant difference was detected between the two groups. There were no significant differences between the AADI and the AGV implant on the rates of adverse events. CONCLUSIONS: The AADI is more effective in both its surgical success rate and reducing IOP and AGM. And the two implants may have comparable incidences of adverse events.

Nipple-areolar complex (NAC) or skin flap ischemia necrosis post nipple-sparing mastectomy (NSM)-analysis of clinicopathologic factors and breast magnetic resonance imaging (MRI) features.

BACKGROUND: The purpose of this study is to identify clinicopathologic factors and/or preoperative MRI vascular patterns in the prediction of ischemia necrosis of the nipple-areola complex (NAC) or skin flap post nipple-sparing mastectomy (NSM). METHODS: We performed a retrospective analysis of 441 NSM procedures from January 2011 to September 2021 from the breast cancer database at our institution. The ischemia necrosis of NAC or skin flap was evaluated in correlation with clinicopathologic factors and types of skin incision. Patients who received NSM with preoperative MRI evaluation were further evaluated for the relationship between vascular pattern and the impact on ischemia necrosis of NAC or skin flap. RESULTS: A total of 441 cases with NSM were enrolled in the current study, and the mean age of the cases was 49.1 ± 9.8 years old. A total of 41 (9.3%) NSM procedures were found to have NAC ischemia/necrosis. Risk factors were evaluated of which old age, large mastectomy specimen weight (> 450 g), and peri-areola incision were identified as predictors of NAC necrosis. Two-hundred seventy NSM procedures also received preoperative MRI, and the blood supply pattern was 18% single-vessel type and 82% double-vessel pattern. There were no correlations between MRI blood supply patterns or types of skin flap incisions with ischemia necrosis of NAC. There were also no correlations between blood loss and the pattern or size of the blood vessel. CONCLUSION: Factors such as the type of skin incision, age, and size of mastectomy weight played an important role in determining ischemia necrosis of NAC; however, MRI vascular (single or dual vessel supply) pattern was not a significant predictive factor.

Drivers of foliar 15 N trends in southern China over the last century.

Foliar stable nitrogen (N) isotopes (δ15 N) generally reflect N availability to plants and have been used to infer about changes thereof. However, previous studies of temporal trends in foliar δ15 N have ignored the influence of confounding factors, leading to uncertainties on its indication to N availability. In this study, we measured foliar δ15 N of 1811 herbarium specimens from 12 plant species collected in southern China forests from 1920 to 2010. We explored how changes in atmospheric CO2 , N deposition and global warming have affected foliar δ15 N and N concentrations ([N]) and identified whether N availability decreased in southern China. Across all species, foliar δ15 N significantly decreased by 0.82‰ over the study period. However, foliar [N] did not decrease significantly, implying N homeostasis in forest trees in the region. The spatiotemporal patterns of foliar δ15 N were explained by mean annual temperature (MAT), atmospheric CO2 ( P CO 2 ), atmospheric N deposition, and foliar [N]. The spatiotemporal trends of foliar [N] were explained by MAT, temperature seasonality, P CO 2 , and N deposition. N deposition within the rates from 5.3 to 12.6 kg N ha-1  year-1 substantially contributed to the temporal decline in foliar δ15 N. The decline in foliar δ15 N was not accompanied by changes in foliar [N] and therefore does not necessarily reflect a decline in N availability. This is important to understand changes in N availability, which is essential to validate and parameterize biogeochemical cycles of N.

A Bit-Tracking Knowledge-Based Query Tree for RFID Tag Identification in IoT Systems.

In an IoT (Internet of Things) system where each IoT device has one/many RFID tags, there might be many RFID tags. However, when multiple tags respond to the reader's interrogation at the same time, their signals collide. Due to the collision, the reader must request the colliding tags to retransmit their IDs, resulting in higher communication overhead and longer identification time. Therefore, this paper presents a Bit-tracking Knowledge-based Query Tree (BKQT), which uses two techniques: knowledge, which stores all the tag IDs that can possibly occur, and bit tracking, which allows the reader to detect the locations of the collided bits in a collision slot. BKQT constructs a query tree for all possible tags, called a k-tree, by using knowledge while it constructs bit-collision cases and the corresponding actions for each node in this k-tree by using bit tracking. In the identification process, BKQT traverses this constructed k-tree and thus identifies the colliding tags faster by taking the actions according to the happening bit-collision cases. From the simulation results, BKQT can improve the identification time by 44.3%, 46.4%, and 25.1%, compared with the previous knowledge-based protocols, Knowledge Query Tree (KQT), Heuristic Query Tree (H-QT), Query Tree with Shortcutting and Couple Resolution (QTSC), respectively.

Ribosome assembly factor URB1 contributes to colorectal cancer proliferation through transcriptional activation of ATF4.

Ribosome assembly factor URB1 is essential for ribosome biogenesis. However, its latent role in cancer remains unclear. Analysis of The Cancer Genome Atlas database and clinical tissue microarray staining showed that URB1 expression was upregulated in colorectal cancer (CRC) and prominently related to clinicopathological characteristics. Silencing of URB1 hampered human CRC cell proliferation and growth in vitro and in vivo. Microarray screening, ingenuity pathway analysis, and JASPAR assessment indicated that activating transcription factor 4 (ATF4) and X-box binding protein 1 (XBP1) are potential downstream targets of URB1 and could transcriptionally interact through direct binding. Silencing of URB1 significantly decreased ATF4 and cyclin A2 (CCNA2) expression in vivo and in vitro. Restoration of ATF4 effectively reversed the malignant proliferation phenotype of URB1-silenced CRC cells. Dual-luciferase reporter and ChIP assays indicated that XBP1 transcriptionally activated ATF4 by binding with its promoter region. X-box binding protein 1 colocalized with ATF4 in the nuclei of RKO cells, and ATF4 mRNA expression was positively regulated by XBP1. This study shows that URB1 contributes to oncogenesis and CRC growth through XBP1-mediated transcriptional activation of ATF4. Therefore, URB1 could be a potential therapeutic target for CRC.

Development and validation of a survival nomogram for patients with Siewert type II/III adenocarcinoma of the esophagogastric junction based on real-world data.

BACKGROUND: The clinical staging systems for adenocarcinoma of the esophagogastric junction (AEG) are controversial. We aimed to propose a prognostic nomogram based on real-world data for predicting survival of Siewert type II/III AEG patients after surgery. METHODS: A total of 396 patients with Siewert type II/III AEG diagnosed and treated at the Center for Gastrointestinal Surgery, the First Affiliated Hospital, Sun Yat-sen University, from June 2009 to June 2017 were enrolled. The original data of 29 variables were exported from the electronic medical records system. The nomogram was established based on multivariate Cox regression coefficients, and its performance was measured using Harrell's concordance index (C-index), receiver operating characteristic (ROC) curve analysis and calibration curve. RESULTS: A nomogram was constructed based on nine variables. The C-index for overall survival (OS) prediction was 0.76 (95% CI, 0.72 to 0.80) in the training cohort, in the validation-1 cohort was 0.79 (95% CI, 0.72 to 0.86), and 0.73 (95% CI, 0.67 to 0.80) in the validation-2 cohort. Time-dependent ROC curves and calibration curves in all three cohorts showed good prognostic predictive accuracy. We further proved the superiority of the nomogram in predictive accuracy for OS to pathological TNM (pTNM) staging system and other independent prognostic factors. Kaplan-Meier survival curves demonstrated the pTNM stage, grade of differentiation, positive lymph node, log odds of positive lymph node and organ invasion were prognostic factors with good discriminative ability. CONCLUSION: The established nomogram demonstrated a more precise prognostic prediction for patients with Siewert type II/III AEG.

A Spatiotemporal-Oriented Deep Ensemble Learning Model to Defend Link Flooding Attacks in IoT Network.

(1) Background: Link flooding attacks (LFA) are a spatiotemporal attack pattern of distributed denial-of-service (DDoS) that arranges bots to send low-speed traffic to backbone links and paralyze servers in the target area. (2) Problem: The traditional methods to defend against LFA are heuristic and cannot reflect the changing characteristics of LFA over time; the AI-based methods only detect the presence of LFA without considering the spatiotemporal series attack pattern and defense suggestion. (3) Methods: This study designs a deep ensemble learning model (Stacking-based integrated Convolutional neural network-Long short term memory model, SCL) to defend against LFA: (a) combining continuous network status as an input to represent "continuous/combination attacking action" and to help CNN operation to extract features of spatiotemporal attack pattern; (b) applying LSTM to periodically review the current evolved LFA patterns and drop the obsolete ones to ensure decision accuracy and confidence; (c) stacking System Detector and LFA Mitigator module instead of only one module to couple with LFA detection and mediation at the same time. (4) Results: The simulation results show that the accuracy rate of SCL successfully blocking LFA is 92.95%, which is 60.81% higher than the traditional method. (5) Outcomes: This study demonstrates the potential and suggested development trait of deep ensemble learning on network security.

Effectiveness of Acupuncture Therapy on Postoperative Nausea and Vomiting After Gynecologic Surgery: A Meta-Analysis and Systematic Review.

PURPOSE: The aim of this study was to evaluate the effectiveness and safety of acupuncture therapy (AT) on postoperative nausea and vomiting (PONV) after gynecologic surgery (GS). DESIGN: A meta-analysis using a systematic search strategy was performed. METHODS: A comprehensive literature search of all published randomized controlled trials or prospective cohort studies assessing the effectiveness of AT on PONV in patients undergoing GS was conducted in three databases: PubMed, EMBASE, and Cochrane Library. The incidence of PONV, the use of rescue antiemetics, and side effects of AT were analyzed using the Review Manager 5.3 software. FINDINGS: Nine randomized controlled trials and one prospective cohort study identified in the literature search from database inception (1966) to December 31, 2019, including 1,075 participants were included in the present study. AT significantly reduced the risk of developing postoperative nausea and postoperative vomiting by 48% (relative risk = 0.52; 95% confidence interval, 0.44 to 0.61; P < .00001) and 42% (relative risk = 0.58; 95% confidence interval, 0.49 to 0.68; P < .00001), respectively. No significant differences in the incidence of side effects such as bleeding and needle pain were observed between groups (P = .54). AT was also associated with a lower rate of rescue antiemetic usage (P < .00001) and a higher degree of satisfaction with postoperative recovery (P < .0001). Moreover, the optimal therapeutic effect of AT on preventing PONV was achieved when the treatment time was controlled within 30 minutes and transcutaneous acupoint electrical stimulation was applied. CONCLUSION: AT is an effective and safe physical therapy for the prophylaxis of PONV in patients undergoing GS.

BTB domain-containing 7 predicts low recurrence and suppresses tumor progression by deactivating Notch1 signaling in breast cancer.

PURPOSE: BTB domain-containing 7 (BTBD7) has been found to regulate epithelial tissue remodeling and branched organ formation and has been reported to modulate the biological behavior of several cancers. However, its role in breast cancer has not been identified. This study investigated the biological role and prognostic value of BTBD7 in breast cancer. METHODS: We identified the BTBD7 expression pattern using the GENT2 database and assessed its expression in breast cancer tissue and cell lines using quantitative reverse transcription polymerase chain reaction, western blot, and immunohistochemistry. We conducted a clinical relevance and survival analysis on a cohort of 121 breast cancer cases from our follow-up and validated it in a Kaplan-Meier plotter. The gain-loss effect of BTBD7 on cell proliferation, invasion, and migration was detected in vitro. We employed a xenograft mouse metastatic model for in vivo validation and performed a Cignal Finder Cancer 10-Pathway Reporter Array, western blot, immunofluorescence, Cell Counting Kit-8, and transwell invasion/migration assays to analyze the potential mechanism. RESULTS: BTBD7 was downregulated in human breast cancer cell lines and tissues. Decreased BTBD7 expression correlated with a positive lymph node status, lymphovascular invasion, and TNM stage, while high BTBD7 expression correlated with low breast cancer recurrence. BTBD7 suppressed cell proliferation, invasion/migration, and tumor metastasis in breast cancer. The mechanism studied suggested that the inhibitory role of BTBD7 was through the deactivation of Notch1 signaling in breast cancer. CONCLUSION: BTBD7 suppresses tumor progression, and its high expression correlates with low recurrence in breast cancer.

Degradation of an appetitive olfactory memory via devaluation of sugar reward is mediated by 5-HT signaling in the honey bee.

Conditioned taste aversion (CTA) learning induces the devaluation of a preferred food through its pairing with a stimulus inducing internal illness. In invertebrates, it is still unclear how this aversive learning impairs the memories of stimuli that had been associated with the appetitive food prior to its devaluation. Here we studied this phenomenon in the honey bee and characterized its neural underpinnings. We first trained bees to associate an odorant (conditioned stimulus, CS) with appetitive fructose solution (unconditioned stimulus, US) using a Pavlovian olfactory conditioning. We then subjected the bees that learned the association to a CTA training during which the antennal taste of fructose solution was contingent or not to the ingestion of quinine solution, which induces malaise a few hours after ingestion. Only the group experiencing contingent fructose stimulation and quinine-based malaise exhibited a decrease in responses to the fructose and a concomitant decrease in odor-specific retention in tests performed 23 h after the original odor conditioning. Furthermore, injection of dopamine- and serotonin-receptor antagonists after CTA learning revealed that this long-term decrease was mediated by serotonergic signaling as its blockade rescued both the responses to fructose and the odor-specific memory 23 h after conditioning. The impairment of a prior CS memory by subsequent CTA conditioning confirms that bees retrieve a devaluated US representation when presented with the CS. Our findings further highlight the importance of serotonergic signaling in aversive learning in the bee and uncover mechanisms underlying aversive memories induced by internal illness in invertebrates.

Lymph node yield, survival benefit, and safety of high and low ligation of the inferior mesenteric artery in colorectal cancer surgery: a systematic review and meta-analysis.

PURPOSE: The aim of this meta-analysis was to compare high inferior mesenteric artery (IMA) ligation (HL) with low IMA ligation (LL) for the treatment of colorectal cancer and to evaluate the lymph node yield, survival benefit, and safety of these surgeries. METHODS: PubMed, Embase, Cochrane Library, Web of Science, and China Biomedical Literature Database (CBM) were systematically searched for relevant articles that compared HL and LL for sigmoid or rectal cancer. We calculated the odds ratio (OR) with 95% confidence intervals (CIs) for dichotomous outcomes and the weighted mean difference (WMD) for continuous outcomes. RESULTS: In total, 30 studies were included in this analysis. There were significantly higher odds of anastomotic leakage and urethral dysfunction in patients treated with HL compared to those treated with LL (OR = 1.29; 95% CI = 1.08 to 1.55; OR = 2.45; 95% CI = 1.39 to 4.33, respectively). There were no significant differences between the groups in terms of the total number of harvested lymph nodes, the number of harvested lymph nodes around root of the IMA, local recurrence rate, and operation time. Further, no statistically significant group differences in 5-year overall survival rates and 5-year disease-free survival rates were detected among all patients nor among subgroups of stage II patients and stage III patients, respectively. CONCLUSIONS: LL can achieve equivalent lymph node yield to HL, and both procedures have similar survival benefits. However, LL is associated with a lower incidence of leakage and urethral dysfunction. Thus, LL is recommended for colorectal cancer surgery.

Social-Aware Peer Discovery for Energy Harvesting-Based Device-to-Device Communications.

In Device-to-Device (D2D) communications, the first step is to find all of the neighboring peers in the network by performing a peer discovery process. Most previous studies use the social behaviors of the users to adjust the sending rates of the peer discovery messages (i.e., beacons) under the constraint of consumed power for increasing the Peer Discovery Ratio (PDR). However, these studies do not consider the potential for energy harvesting, which allows for the User Equipments (UEs) to procure additional power within charging areas. Accordingly, this paper proposes an Energy-Ratio Rate Decision (ERRD) algorithm that comprises three steps, namely Social Ratio Allocation (SRA), Energy Ratio Allocation (ERA), and Beacon Rate Decision (BRD). The SRA step determines the allocated power quantum for each UE from the total budget power based on the social behavior of the UE. The ERA step then adjusts this allocated power quantum in accordance with the power that is harvested by the UE. Finally, the BRD step computes the beacon rate for the UE based on the adjusted power quantum. The simulation results show that ERRD outperforms the previously-reported Social-Based Grouping (SBG) algorithm by 190% on the PDR for a budget power of one watt and 8% for a budget power of 20 watts.

Motor hyperactivity of the iron-deficient rat - an animal model of restless legs syndrome.

BACKGROUND: Abnormal striatal dopamine transmission has been hypothesized to cause restless legs syndrome. Dopaminergic drugs are commonly used to treat restless legs syndrome. However, they cause adverse effects with long-term use. An animal model would allow the systematic testing of potential therapeutic drugs. A high prevalence of restless legs syndrome has been reported in iron-deficient anemic patients. We hypothesized that the iron-deficient animal would exhibit signs similar to those in restless legs syndrome patients. METHODS: After baseline polysomnographic recordings, iron-deficient rats received pramipexole injection. Then, iron-deficient rats were fed a standard rodent diet, and polysomnographic recording were performed for 2 days each week for 4 weeks. RESULTS: Iron-deficient rats have low hematocrit levels and show signs of restless legs syndrome: sleep fragmentation and periodic leg movements in wake and in slow-wave sleep. Iron-deficient rats had a positive response to pramipexole treatment. After the iron-deficient rats were fed the standard rodent diet, hematocrit returned to normal levels, and sleep quality improved, with increased average duration of wake and slow-wave sleep episodes. Periodic leg movements decreased during both waking and sleep. Hematocrit levels positively correlated with the average duration of episodes in wake and in slow-wave sleep and negatively correlated with periodic leg movements in wake and in sleep. Western blot analysis showed that striatal dopamine transporter levels were higher in iron-deficient rats. CONCLUSIONS: The iron-deficient rat is a useful animal model of iron-deficient anemic restless legs syndrome. © 2017 International Parkinson and Movement Disorder Society.

Radiation Safety Assessment in Prostate Cancer Treatment: A Predictive Approach for I-125 Brachytherapy.

This study uses Monte Carlo simulation and experimental measurements to develop a predictive model for estimating the external dose rate associated with permanent radioactive source implantation in prostate cancer patients. The objective is to estimate the accuracy of the patient's external dose rate measurement. First, I-125 radioactive sources were implanted into Mylar window water phantoms to simulate the permanent implantation of these sources in patients. Water phantom experimental measurement was combined with Monte Carlo simulation to develop predictive equations, whose performance was verified against external clinical data. The model's accuracy in predicting the external dose rate in patients with permanently implanted I-125 radioactive sources was high (R2 = 0.999). A comparative analysis of the experimental measurements and the Monte Carlo simulations revealed that the maximum discrepancy between the measured and calculated values for the water phantom was less than 5.00%. The model is practical for radiation safety assessments, enabling the evaluation of radiation exposure risks to individuals around patients with permanently implanted I-125 radioactive sources.