Radiotracer Research Articles

Impact of superabsorbent hydrogels on microbial community and atrazine fate in soils by 14C-labeling techniques

The accumulation of atrazine in soils can create environmental challenges, potentially posing risks to human health. Superabsorbent hydrogel (SH)-based formulations offer an eco-friendly approach to accelerate herbicide degradation. However, the impact of SHs on soil microbial community structure, and thus on the fate of atrazine, remains uncertain. In this study, a radioactive tracer was employed to investigate the influence of SHs on microbial communities and atrazine transformation in soils. The results revealed that the mineralization of atrazine in active soils was considerably greater than that in sterilized soils. Atrazine degradation proceeded rapidly under SH treatment, indicating the potential of SH to accelerate atrazine degradation. Furthermore, SH addition did not alter the atrazine degradation pathway in soils, which included dealkylation, dechlorination and hydroxylation. The relative abundance of dominant microbial population was influenced by the presence of SHs in the soil. Additionally, SH application led to an increased relative abundance of Lysobacter, suggesting its potential involvement in atrazine degradation. These findings reveal the significance of soil microorganisms and SH in atrazine degradation, offering crucial insights for the development of effective strategies for atrazine remediation and environmental sustainability.

Therapeutic impacts of GNE‑477‑loaded H2O2 stimulus‑responsive dodecanoic acid‑phenylborate ester‑dextran polymeric micelles on osteosarcoma.

Osteosarcoma (OS) is a highly malignant primary bone neoplasm that is the leading cause of cancer‑associated death in young people. GNE‑477 belongs to the second generation of mTOR inhibitors and possesses promising potential in the treatment of OS but dose tolerance and drug toxicity limit its development and utilization. The present study aimed to prepare a novel H2O2 stimulus‑responsive dodecanoic acid (DA)‑phenylborate ester‑dextran (DA‑B‑DEX) polymeric micelle delivery system for GNE‑477 and evaluate its efficacy. The polymer micelles were characterized by morphology, size and critical micelle concentration. The GNE‑477 loaded DA‑B‑DEX (GNE‑477@DBD) tumor‑targeting drug delivery system was established and the release of GNE‑477 was measured. The cellular uptake of GNE‑477@DBD by three OS cell lines (MG‑63, U2OS and 143B cells) was analyzed utilizing a fluorescent tracer technique. The hydroxylated DA‑B was successfully grafted onto dextran at a grafting rate of 3%, suitable for forming amphiphilic micelles. Following exposure to H2O2, the DA‑B‑DEX micelles ruptured and released the drug rapidly, leading to increased uptake of GNE‑477@DBD by cells with sustained release of GNE‑477. The in vitro experiments, including MTT assay, flow cytometry, western blotting and RT‑qPCR, demonstrated that GNE‑477@DBD inhibited tumor cell viability, arrested cell cycle in G1 phase, induced apoptosis and blocked the PI3K/Akt/mTOR cascade response. In vivo, through the observation of mice tumor growth and the results of H&E staining, the GNE‑477@DBD group exhibited more positive therapeutic outcomes than the free drug group with almost no adverse effects on other organs. In conclusion, H2O2‑responsive DA‑B‑DEX presents a promising delivery system for hydrophobic anti‑tumor drugs for OS therapy.

De-Escalating the Extent of Sentinel Lymph Node Biopsy in Patients with Ductal Carcinoma in Situ Undergoing Mastectomy

BackgroundSentinel lymph node biopsy (SLNB) for axillary staging in patients with ductal carcinoma in situ (DCIS) undergoing mastectomy is debated due to low nodal positivity rate and risk of morbidity. Standard SLNB entails removing all lymph nodes (LN) that have a radioactive count >10% of the most radioactive node, contain blue dye or are palpably suspicious. In this study, we hypothesize that judicious SLNB with attempt to remove only the node with the highest radioactive count provides sufficient pathologic information while minimizing morbidity. MethodA single institution prospective database was retrospectively reviewed to identify women with DCIS who underwent mastectomy and SLNB between 2010–22. Patient characteristics, number of SLNs retrieved, pathologic results and long-term upper extremity complications were analyzed. ResultsA total of 743 LNs were removed in 324 pts. Median [IQR] age was 62 [51–70] years. Dual tracer technique, with technetium-99m labeled radiocolloid and blue dye, was used in 311 (96%) pts, whereas single agent (radioisotope or blue dye alone) was utilized in 9 (2.8%) and 4 (1.2%) patients, respectively. Median [IQR] number of SLN removed was 2 [1-3] (range 1-9). In 99% of cases, the SLN with the highest radioactive count was identified among the first 3 dissected LNs. Final pathology revealed upstaging to invasive cancer in 27.5% (n=89) of the breasts and nodal positivity in 1.9% (n=6) of the patients. In all 6 cases, metastatic disease was identified in the LN with highest radioactive count among the LNs retrieved. No additional metastatic nodes were identified after >3 SLN had been removed. At median follow-up of 57 (range 28-87) months, 8.3% (n=27) of pts complained of long-term upper extremity symptoms. 7.1% (23 pts) were referred to physical therapy for symptoms such as swelling, fullness, heaviness, stiffness, or sensory discomfort in the upper extremity and/or axillary cording. Long-term upper extremity complications were higher when >3 SLNs compared to ≤3 SLNs were removed (10.4% vs 6.5%, p=0.005). ConclusionIn this cohort of patients with DCIS undergoing mastectomy who were upstaged on final pathology to node positive invasive cancers, the SLN with the highest radioactive count provided sufficient information for axillary staging. Acknowledging that the “hottest” LN is not always the first one removed, these data support an increased likelihood of developing long-term complications when more than three SLNs are removed. Rather than comprehensive removal of all SLNs meeting the standard “10% rule,” prioritizing the sequence of removal to the highest count provides the same prognostic information with reduced morbidity.

SF6 Tracer Technique to Estimate Methane Emission in a Dual-Flow Continuous Culture System: Test and Application

This study aimed to evaluate the sulfur hexafluoride (SF6) tracer technique for estimating methane (CH4) emissions in dual-flow continuous culture systems (DFCCS). In experiment 1 (Exp1), fermenters were filled with water, and known CH4 concentrations (0, 1.35, 2.93, or 4.43 g/d) were injected using permeation tubes with SF6 release rates (3.30 or 9.65 mg/d). Headspace gas was collected using canisters, and the SF6 technique estimated CH4 recovery. Experiment 2 (Exp2) involved a DFCCS fermentation trial with ruminal fluid from three Holstein cows, testing diets with soybean meal or its partial replacement (50%) by Chlorella or Spirulina. Headspace gas was collected at intervals post-feeding. Standard curves for SF6 and CH4 quantification were inadequate for DFCCS samples, with the CH4:SF6 ratio differing from standards, indicating the data needs further SF6 release rate evaluation. In Exp1, a high correlation (r = 0.97) was found between infused and calculated CH4, indicating good repeatability. Low and high SF6 rates performed similarly at low CH4 infusion, but high SF6 overestimated CH4 at high infusion. Exp2 showed CH4 emissions irrespective of SF6 rate and indicated reduced CH4 emissions and increased NDF degradation with algae-containing diets. Further evaluation of the SF6 tracer technique is warranted for DFCCS.

Dietary protein splanchnic uptake and digestibility via stable isotope tracers.

Dietary proteins are broken down into peptides across the gastrointestinal tract, with skeletal muscle being a primary deposition site for amino acids in the form of incorporation into, for example, metabolic and structural proteins. It follows that key research questions remain as to the role of amino acid bioavailability, of which protein digestibility and splanchnic sequestration (absorption and utilization) of amino acids are determining factors, impact upon muscle protein synthesis (MPS) in clinical states. Elevated splanchnic amino acid uptake has been implicated in anabolic resistance (i.e. attenuated anabolic responses to protein intake) observed in ageing, though it is unclear whether this limits MPS. The novel 'dual stable isotope tracer technique' offers a promising, minimally invasive approach to quantify the digestion of any protein source(s). Current work is focused on the validation of this technique against established methods, with scope to apply this to clinical and elderly populations to help inform mechanistic and interventional insights. Considerations should be made for all facets of protein quality; digestibility of the protein, absorption/utilization and subsequent peripheral bioavailability of amino acids, and resultant stimulation of MPS. Stable isotope tracer techniques offer a minimally invasive approach to achieve this, with wide-ranging clinical application.

Commentary: Tracing the fate of metabolic substrates during changes in whole-body energy expenditure in mice

For small mammals, such as mice, cannulation procedures can be quite challenging, limiting research associated with tracing isotopically labelled substrates at the whole-animal level. When cannulation in mice is possible, assessment of substrate use is further limited to when mice are either under anesthesia or are at rest, as there are no studies directly quantifying substrate use during exercise in mice. The use of isotopic tracer techniques has greatly advanced our knowledge in understanding how metabolic substrates (carbohydrates, amino acids, and fatty acids) contribute to whole-body metabolism. However, research regarding tissue-specific fuel use contributions to whole-body energy expenditure in mice at varying metabolic intensities (i.e., exercise) is lacking, despite the popularity of using mice in a variety of metabolic models. In this commentary, we briefly discuss the methodologies, advantages, and disadvantages of using radiolabelled, positron emission, and stable isotopes with a specific focus on fatty acids. We highlight recent mouse studies that have used creative experimental designs employing the use of isotopic tracer techniques and we briefly discuss how these methodologies can be further pursued to deepen our understanding of substrate use during exercise. Lastly, we show findings of a recent study we performed using a radiolabelled fatty acid tracer (14C-bromopalmitic acid) to determine fatty acid uptake in 16 muscles, two brown and two white adipose tissue depots during submaximal exercise in deer mice.

An Experimental Study of the Morphological Evolution of Rills on Slopes under Rainfall Action

Accurately monitoring the morphology and spatiotemporal evolution characteristics of the entire process of slope erosion rill development is essential to circumvent the limitations inherent in traditional methods that rely on average flow velocity for hydrodynamic parameter calculations. This study employs an environmental chamber and a self-developed slope erosion test device to perform erosion tests on slopes with varying gradients and rainfall intensities. By integrating the structure-from-motion (SfM) method, fixed grid coordinate method, and continuous camera combined with the dye tracer technique, the morphological indexes and hydrodynamic parameters of the entire rill development process are precisely computed. The main conclusions are as follows: The entire process of slope rill development can be divided into three distinct stages. The initial stage is characterized by the appearance of tiny rills with mild erosion. The middle stage involves severe transverse spreading erosion and longitudinal undercutting, resulting in diverse rill morphologies. The final stage is marked by the stabilization of morphological characteristics. The peak slope soil loss is observed during the middle stage of rill development. The most effective parameters for characterizing slope soil loss from the beginning to the end are the Reynolds number and flow shear stress, the Froude number and flow shear stress, and the Froude number during different periods. Throughout the development of rills, the flow velocity initially decreases and then gradually increases until it stabilizes. The morphological indexes, including rill density, dissected degree, inclination, and complexity, generally show an increasing trend. However, in the middle stage, the rate of increase slows down, followed by a sharp rise at certain points. The optimal hydraulic parameters for evaluating rill density across different slope gradients, which were found to be the Darcy–Weisbach drag coefficient and real-time flow velocity, for assessing rill dissected degree, complexity, and inclination, were the Reynolds number and flow power. Under varying rainfall intensities, the most effective hydraulic and kinetic parameters for evaluating rill density, dissected degree, and inclination were flow shear stress and Reynolds number; for assessing rill complexity, the Reynolds number and flow power were used. The findings of this research enhance the accuracy of hydrodynamic parameter calculations in rill erosion tests, enable precise prediction of rill development trends on slopes, and offer innovative approaches for real-time dynamic monitoring of rill morphology and characteristics. These advancements are of significant importance for soil and water conservation and sustainability.

Tracing semi-quantitatively the absorption and removal of organic pollutants in human hair based on secondary ion mass spectrometry

Human hair has become a promising non-invasive matrix in assessing exposure to environmental organic pollutants (OPs). However, exogenous contaminants, which were absorbed into the hair via sweat, sebum, and air particles/dust, could contribute to OP levels in hair and interfere with the precise exposure assessment. So far, the microscopic mechanisms underlying the absorption of exogenous OPs into hair remain inadequately understood. This study focused on the in-situ investigation of the diffusion processes of exogenous OPs into the hair structure using secondary ion mass spectrometry (SIMS) and isotopic tracer techniques. Results showed that the relative signal intensities of deuterium-labeled tris(1,3-dichloro-2-propyl) phosphate (TDCPP), 1-hydroxypyrene (1-OH-Pry), and bisphenol A (BPA) in the hair cortex were notably elevated after a 6-hour exposure. Diffusion coefficients of contaminants were related to their molecular weight, and absorption volumes to their water solubility and molecular structures. Exposure duration and solvent influenced the rate of diffusion and absorption volumes. The distribution of deuterium-labeled molecules in exposed hair samples after washing with two different solvents (acetone or water) was similar to that before washing. Our findings revealed the diffusion of OPs in hair cross-sections, indicating exogenous contributions to contaminants that are biologically incorporated into the hair.

Fibroblast growth factor-21 potentiates the stimulatory effects of 1,25-dihydroxyvitamin D3 on transepithelial calcium transport and TRPV6 Ca2+ channel expression

Fibroblast growth factor (FGF)-21 is a salient liver-derived endocrine regulator for metabolism of glucose and triglyceride as well as bone remodeling. Previously, certain peptides in the FGF family have been shown to modulate calcium absorption across the intestinal epithelia. Since FGF21 receptor, i.e., FGF receptor-1, is abundantly expressed in the enterocytes, there was a possibility that FGF21 might exert direct actions on the intestine. Herein, a large-scale production of recombinant FGF21 at the multi-gram level was developed in order to minimize variations among various batches. In the oral glucose tolerance test, recombinant FGF21 was found to reduce plasma glucose levels in mice fed high-fat diet. A series of experiments applying radioactive tracer 45Ca in Ussing chamber showed that FGF21 potentiated the stimulatory effect of low-dose 1,25-dihydroxyvitamin D3 [10 nM 1,25(OH)2D3] on the transepithelial calcium transport across intestinal epithelium-like Caco-2 monolayer. FGF21 + 1,25(OH)2D3 also decreased transepithelial resistance, but had no effect on epithelial potential difference or short-circuit current. Furthermore, 1,25(OH)2D3 alone upregulated the Caco-2 mRNA expression of the major apical calcium channels, i.e., transient receptor potential vanilloid subfamily member 6 (TRPV6), which was further elevated by a combination of FGF21 and 1,25(OH)2D3, consistent with the upregulated TRPV6 protein expression in enterocytes of FGF21-treated mice. However, FGF21 was without effects on the mRNA expression of voltage-gated calcium channel 1.3, calbindin-D9k, plasma membrane Ca2+-ATPase 1b, claudin-12 or claudin-15. In conclusion, FGF21 did exert a direct action on the intestinal epithelial cells by potentiating the 1,25(OH)2D3-enhanced calcium transport, presumably through the upregulation of TRPV6 expression.

FAPI-PET-CT for quantification of the tissue response in rheumatic diseases

Fibroblast activation protein (FAP) is mainly found on the surface of activated fibroblasts but is not expressed on the surface of inactive fibroblasts. Selective FAP inhibitors (FAPI), which are coupled to a radioactive tracer, can be used to quantify profibrotic and proinflammatory fibroblasts in patients using FAPI positron emission tomography (PET) computed tomography (CT). Following initial applications in neoplastic diseases, FAPI-PET/CT is also increasingly being applied in rheumatological diseases. The first studies have shown that in patients with systemic sclerosis (SSc) FAPI accumulates in actively fibrotically remodeled pulmonary and myocardial areas, that a high FAPI accumulation is associated with the risk of short-term progression and that this accumulation in the lungs regresses after successful treatment. In cases of immunoglobulin 4 (IgG4)-associated diseases (IgG4 rheumatic disease, RD), the FAPI signal correlates with the histological accumulation of activated fibroblasts and a poorer response to treatment to inhibit inflammation. Fibroblasts in chronically inflamed tissue, such as patients with inflammatory joint diseases, vasculitis or myositis, also express FAP and can be quantified by FAPI-PET/CT. The treatment-induced change of the phenotype from a destructive IL-6+/MMP3+THY1+ fibroblast subtype to an inflammation inhibiting CD200+DKK3+ subtype can be mechanistically demonstrated using FAPI-PET/CT. These studies provide indications that FAPI-PET/CT enables quantification of the tissue response in patients with fibrosing and chronic inflammatory diseases and can be used for patient stratification; however, further studies are essential for validation of the use of FAPI-PET/CT as a molecular imaging marker.

Dynamic Replacement of Soil Inorganic Carbon under Water Erosion

The dynamic replacement of soil organic carbon represents a pivotal mechanism through which water erosion modulates soil–atmosphere CO2 fluxes. However, the extent of this dynamic replacement of soil inorganic carbon within this process remains unclear. In our study, we focused on Yuanmou County, China, a prototypical region afflicted by water erosion, as our study area. We leveraged the WaTEM/SEDEM model to quantify the dynamic replacement of soil carbon, accounted for the average annual net change in soil carbon pools, and used isotope tracer techniques to track and measure the process of the coupled carbon–water cycling. This comprehensive approach enabled us to scrutinize the dynamic replacement of soil carbon under water erosion and delineate its ramifications for the carbon cycle. Our findings unveiled that the surface soil carbon reservoir in the Yuanmou area receives an annual replacement of 47,600 ± 12,600 tons following water erosion events. A substantial portion, amounting to 39,700 ± 10,500 tons, stems from the dynamic replacement of soil inorganic carbon facilitated by atmospheric carbon. These results underscore the critical role of the dynamic replacement of soil inorganic carbon in altering the soil–atmosphere CO2 fluxes under water erosion, thereby influencing the carbon cycle dynamics. Consequently, we advocate for the integration of water erosion processes into regional carbon sink assessments to attain a more comprehensive understanding of regional carbon dynamics.

The risk of developing cancer of the digestive organs (excluding intestines) in the South Urals Population Exposed to Radiation Cohort

Evaluation of the low dose effect on population health is still a relevant issue. It requires further studies to improve our understanding of these effects. To solve this problem, it is important to conduct studies of the late effects of radiation exposure with direct risk estimation in the population that combines all strata of the society: people of different sex, age, initial health status, social and economic status. Moreover, this population should be sizeable and has been followed up for a long-term period. This manuscript is the first to present the findings of the analysis of the incidence risk of cancer of all the digestive organs, excluding intestines, and stomach cancer taken separately in members of the Southern Urals Population Exposed to Radiation Cohort depending on the dose accumulated in the stomach over the period from 1956 through 2018. This cohort is comprised of individuals exposed in the Southern Urals in two radiation accidents (on the Techa River and in the East-Urals Radioactive Trace) over the period from 01.01.1950 through 31.12.1960. The cohort also includes those who were born during this period; they could have additional in utero exposure or have exposed parents. The population was affected by long-term combined exposure (external and internal) at the low-to-medium soft tissue dose range (up to 1.1 Gy). The size of the incidence cohort was 47,282 people. Over the follow-up period 01.01.1956-31.12.2018, the number of person-years made up 1 292 930; mean dose to the stomach was 47 mGy, maximum – 1,132 mGy. Excess relative risk of the cancer incidence of the digestive organs was assessed using the Poisson regression analysis. Calculations were performed using the EPICURE Statistical software package. Excess relative risk for stomach cancer with a 2-year minimal, was 0.98/Gy (р=0.026), for all cancers of the digestive organs, excluding intestines, – 0.58/Gy, р=0.06. There was no significant modification of the effect by non-radiation factors. These values of excess relative risk do not disagree with the results of similar studies in the Japanese cohort of the atomic bomb survivors who were compatible in terms of age but had acute exposure at higher doses. No significant dose dependence of the cancer incidence of the oral cavity, esophagus, liver, or pancreas was detected at this stage.

Probing predominant flow areas of enhanced geothermal systems with fuzzy-genetic inversion model: Impacts of initial conditions of fracture network distributions

Predominant flow areas in fractured reservoirs, causing a large amount of fluid loss, are the primary reason for a failed practical enhanced geothermal system project. However, in practical situations, the existed geophysical exploration methods (e.g., microseismic techniques and tracer techniques) are unable to clear all the actual fracture network distribution in fractured reservoirs, so it is difficult to verify the existence state of predominant flow areas. This study aims to create an inversion method based on a fuzzy-genetic algorithm for identifying fracture network distributions, through discussing the influences of different initial guessed fracture network distributions on inversion results. Results show that the random distribution and the fracture aperture range have an obvious impact on inversion results (inversion accuracy rate = 70%). An increase in fracture length scope (>120−210 m) and number (>170) decreases inversion accuracy. Curved-fracture network distribution also leads to a decrease in the accuracy of inversion results. This study would provide suggestions for deep geothermal exploration.

Microbial nitrogen nutrition links to dissolved organic matter properties in East African lakes

East African lakes, especially soda lakes, are home habitats for massive numbers of wildlife such as flamingos, mammals, and fishes. These lakes are known for their high primary production due to local high temperatures, light intensities, and alkalinity (inorganic carbon). However, these lakes, normally within remote areas, receive low nutrient inputs. Ammonium (NH4+) recycling and/or nitrogen fixation can become the major N supply mechanisms for phytoplankton. However, the driving forces of microbial N nutrition in lakes with minimal anthropogenic disturbance remain poorly understood. Using stable isotope tracer techniques, NH4+ recycling rates were measured in 18 lakes and reservoirs in East Africa (Tanzania and Kenya) during the dry season in early 2020. Three functional genes (nifH, gdh, and UreC) relating to microbial N nutrition were also measured. The NH4+ regeneration supported up to 71 % NH4+ uptake. Positive community biological NH4+ demands (CBAD) for all lakes and reservoirs indicate an obvious N demand from microbial community. Our study provides clear evidence that microbial NH4+ uptake rates are closely linked to the dissolved organic matter (DOM) properties (e.g., the absorption coefficient at 254 nm, percents of total fluorescence intensity contributed by microbial humic-like and protein-like components) and that water residence time drives microbial NH4+ recycling by regulating the duration of in-lake DOM processing and influencing algal growth. Phytoplankton, especially those of Cyanophyceae, showed maximum biomass and higher NH4+ recycling rates at a certain range of water residence time (e.g., 5–8 years). However, CBAD showed a decreasing trend with longer water residence time, which may be influenced by changes in the algal community composition (e.g., % Cyanophyceae vs. % Bacillariophyceae). These results indicate that the water residence time and DOM dynamics have the potential to facilitate the understanding of microbial nitrogen supply mechanisms in East African lakes.

Source apportionment of fine particulate matter in middle Indo-Gangetic Plain by coupled radiocarbon –molecular organic tracer method

Despite significant emissions of fine particulate matter (FPM) from the Indo-Gangetic Plain (IGP) that affect the climate and air quality in the region, the sources of these emissions are not adequately addressed. This research uses a combined radiocarbon-molecular organic tracer technique to investigate the degree of contamination, seasonal fluctuations, and contribution of FPM in the middle IGP (Patna), India. The findings indicated levoglucosan (L) as the single primary BB tracer chemical, ranging from 149 ng/m3 to 490 ng/m3 (median 282 ng/m3). Winter (median 462 ng/m3) showed a 2–3 times higher level of L than the monsoon season (median 180 ng/m3). A significant association of L with other organic tracers such as galactosan (G), mannosan (M), vallinic acid, syringic acid, p-hydroxybenzoic acid (pHA) and dehydroabietic acid (DHAA)(r = 0.53 to 0.89, p < 0.05), and moderate connection with Cl− (r = 0.21, p < 0.05), SO42− (r = 0.29, p < 0.05), and NO3- (r = 0.22, p < 0.05) indicated significant BB contribution. However, non-sea salt (nss-K+) was not related to L. Based on seven days of air mass back trajectories and MODIS active fire counts analysis, we conclude that OAs composition is not the local origin but is also impacted by long-range atmospheric transport from Pakistan/Afghanistan, followed by the Bay of Bengal and the Arabian Sea. Chemical analysis of organic tracers and positive matrix factorization (PMF) modeling study identified three unique sources, i.e., biomass burning, secondary aerosols formation, and mixed type (fossil fuels and construction dust) as the primary source of FPM in Patna, accounted for 46.1 %, 28.9 %, and 24.9 %, of total emissions, respectively. The radiocarbon (14 C) analysis of total carbon (TC) samples further supported this conclusion. The results of the 14 C study indicated that emissions from BB, such as wood and stubble, were responsible for 57% of the TC concentration.

Different tracers for sentinel node detection in gynecologic oncology.

In the past decade, sentinel lymph node (SLN) mapping has progressively substituted full lymphadenectomies in gynecologic oncology. In this article, we review the most relevant and the latest literature on this topic. In endometrial and cervical cancer, the current evidence further support the value of indocyanine green (ICG) as tracer of choice for SLN mapping. Experience in vulvar cancer is more limited, with ICG used together with technetium-99 m (Tc-99m) as a dual tracer but ICG, so far, has not been a game changer in this setting as it has been for cervical and endometrial cancer. For most gynecologic cancers, ICG fluorescence imaging is considered now a days the tracer of choice for lymphatic mapping. However, in early-stage vulvar cancer, SLN biopsy with radioactive tracer continues to be the standard-of-care in lymph node status assessment.

Evaluation of [11C]UCB-A positron emission tomography in human brains

BackgroundIn preclinical studies, the positron emission tomography (PET) imaging with [11C]UCB-A provided promising results for imaging synaptic vesicle protein 2A (SV2A) as a proxy for synaptic density. This paper reports the first-in-human [11C]UCB-A PET study to characterise its kinetics in healthy subjects and further evaluate SV2A-specific binding.ResultsTwelve healthy subjects underwent 90-min baseline [11C]UCB-A scans with PET/MRI, with two subjects participating in an additional blocking scan with the same scanning procedure after a single dose of levetiracetam (1500 mg). Our results indicated abundant [11C]UCB-A brain uptake across all cortical regions, with slow elimination. Kinetic modelling of [11C]UCB-A PET using various compartment models suggested that the irreversible two-tissue compartment model best describes the kinetics of the radioactive tracer. Accordingly, the Patlak graphical analysis was used to simplify the analysis. The estimated SV2A occupancy determined by the Lassen plot was around 66%. Significant specific binding at baseline and comparable binding reduction as grey matter precludes the use of centrum semiovale as reference tissue.Conclusions[11C]UCB-A PET imaging enables quantifying SV2A in vivo. However, its slow kinetics require a long scan duration, which is impractical with the short half-life of carbon-11. Consequently, the slow kinetics and complicated quantification methods may restrict its use in humans.

An improved method for evaluating fracture density using pulsed neutron capture logging

Fracture density is a critical fracture evaluation parameter for the optimization and production prediction of hydraulic fracturing models. Non-radioactive tracer techniques (NRT) have successfully used a quantitative fracture density method based on neutron-induced gamma ray from formation elements. Furthermore, fracture density can be calculated using the formation capture cross-section before and after hydraulic fracturing based on pulsed neutron capture logging. However, the response sensitivity of the macroscopic scattering cross section to the fractures will decrease when the fracture density is high due to the neutron self-shielding phenomenon. Therefore, an improved fracture density evaluation method is applied, which combines the macroscopic capture cross section and the neutron self-shielding correction factor. In the new method, the peak area of titanium from the captured gamma spectrum was used to obtain a neutron self-shielding correction factor, in order to improve the sensitivity of fracture density determination. Furthermore, the response of capture cross-section variation to fracture density at various tagged proppant concentrations and formation backgrounds was investigated. The findings indicate that the tagged proppant concentration influences the detection limit of fracture density and the sensitivity of fracture density identification. The accurate calculation range of fracture density using the new method has been extended from 5% to 10% under the condition that the tagged proppant concentration is 0.2%. Meanwhile, water salinity significantly impacts capture cross-section variation, while the effects of porosity, lithology, and fluid type on capture cross-section variation are negligible. A simulated fracturing example demonstrates the method's applicability in various measuring environments. The results show that fracture density and height are consistent with the model settings after correcting for water salinity, and the fracture density calculation error is less than 3%. Therefore, our proposed evaluation method for fracture density corrected for the neutron self-shielding effect improves response sensitivity and fracture density calculation accuracy.

A comparative study of double track anastomosis and tubular esophagogastric anastomosis in laparoscopic radical proximal gastrectomy for upper gastric carcinoma.

e16117 Background: For the upper gastric cancer, especially adenocarcinoma at the esophagogastric junction, the optimal surgical method is still controversial. The purpose of the study is to evaluate the safety and clinical effect of double track (DT) anastomosis in laparoscopic radical proximal gastrectomy (LRPG). Methods: A retrospective analysis was conducted involving 243 patients who underwent LRPG in the Department of Gastrointestinal Surgery, Qilu Hospital of Shandong University from Jan. 2017 to Dec. 2020. Patients were divided into tubular esophagogastric (TG) anastomosis group and double track (DT) anastomosis group, according to the digestive tract reconstruction. Their intraoperative conditions, perioperative recovery and postoperative follow-up were compared. Patients were divided into ≥60 and &lt; 60 groups according to age, to analysis the pros and cons of the two surgical methods in different age groups. According to whether or not indocyanine green (ICG) tracer technology was used during the operation, DT group was also divided into ICG group and non-ICG group. Results: Compared with the TG group, the DT group had less volume of gastric tube drainage, shorter gastric tube drainage time and proton pump inhibitors application time, and lower reuse rate of proton pump inhibitors. However, the DT group had more total operation time and lymph node dissection time. The median follow-up time of the patients was 36.0 months. At the end of study, the 1-year OS rate and DFS rate were 94.2% and 92.6% in the TG group and 95.8% and 93.7% in the DT group. The 3-year OS rate and DFS rate were 90.2% and 85.2% in the TG group and 91.9% and 87.7% in the DT group. And there was no significant difference in survival outcomes between the two groups. The DT group had a lower anastomotic stenosis at 3rd month after surgery. Moreover, the incidence of reflux esophagitis and Gerd Q score in the DT group were lower compared with the TG group at 3rd month, 1st year and 3rd year after surgery. In addition, elderly patients had a higher incidence of short-term complications in DT group compared with TG group. In the ICG analysis, the ICG DT group had significantly shorter total operation time and lymph node dissection time, less intraoperative blood loss and more lymph nodes obtained compared with the non-ICG DT group. Conclusions: DT anastomosis is a safe and effective way in LRPG for upper gastric carcinoma. Although the operation time of it is longer than that of TG anastomosis, it has a better anti-reflux effect and reduces the incidence of dysphagia and anastomotic stenosis. In elderly patients, it is important to minimize operative time and better to use TG anastomosis. The application of ICG tracer technique in LRPG has positive significance.

Systematic review for optimizing sample size in dairy cow methane emission studies in temperate regions: a comprehensive methodological approach.

This research introduces a systematic framework for calculating sample size in studies focusing on enteric methane (CH4, g/kg of DMI) yield reduction in dairy cows. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive search across the Web of Science, Scopus, and PubMed Central databases for studies published from 2012 to 2023. The inclusion criteria were: studies reporting CH4 yield and its variability in dairy cows, employing specific experimental designs (Latin Square Design (LSD), Crossover Design, Randomized Complete Block Design (RCBD), and Repeated Measures Design) and measurement methods (Open-circuit respirometry chambers (RC), the GreenFeed system, and the sulfur hexafluoride tracer technique), conducted in Canada, the United States and Europe. A total of 150 studies, which included 177 reports, met our criteria and were included in the database. Our methodology for using the database for sample size calculations began by defining 6 CH4 yield reduction levels (5, 10, 15, 20, 30, and 50%). Utilizing an adjusted Cohen's f formula and a power analysis we calculated the sample sizes required for these reductions in balanced LSD and RCBD reports from studies involving 3 or 4 treatments. The results indicate that within-subject studies (i.e., LSD) require smaller sample sizes to detect CH4 yield reductions compared with between-subject studies (i.e., RCBD). Although experiments using RC typically require fewer individuals due to their higher accuracy, our results demonstrate that this expected advantage is not evident in reports from RCBD studies with 4 treatments. A key innovation of this research is the development of a web-based tool that simplifies the process of sample size calculation (samplesizecalculator.ucdavis.edu). Developed using Python, this tool leverages the extensive database to provide tailored sample size recommendations for specific experimental scenarios. It ensures that experiments are adequately powered to detect meaningful differences in CH4 emissions, thereby contributing to the scientific rigor of studies in this critical area of environmental and agricultural research. With its user-friendly interface and robust backend calculations, this tool represents a significant advancement in the methodology for planning and executing CH4 emission studies in dairy cows, aligning with global efforts toward sustainable agricultural practices and environmental conservation.