Hepatoblastoma is the most common primary malignant paediatric liver tumour and surgery remains the cornerstone of its management. The aim of this article is to present the principles of surgical treatment of hepatoblastoma. All aspects of surgery in hepatoblastoma are discussed, from biopsy, through conventional and laparoscopic liver resections, to extreme resection with adjacent structures, staged hepatectomy and transplantation. Hepatoblastoma (HB) is definitely a “surgical tumour”. Surgery remains the cornerstone of management and complete resection is crucial for cure –3. In reAn overview of historical perspective relevant to the management of HB can be found in Table Biopsy should be performed before chemotherapy.Intraoperative, rapid pathological analysis should be avoided.Fine-needle aspiration biopsy should be avoided for diagnosis, as it does not provide enough tissue to evaluate tumour.As many as five, and preferably ten, cores of tumour should be obtained, where possible, from different regions of the tumour.A biopsy of the adjoining normal liver should be taken for molecular tests.To prevent tumour seeding along the needle tract, the biopsy technique should be coaxial and the needle should be passed through “healthy” liver, which will be resected at the definite tumor resection.A diagnostic tumour biopsy is strongly recommended for all patients with a primary liver tumour. Excluded from this paradigm are benign tumours  in the youngest children, hepatocellular neoplasms not otherwise specified  in older children, and hepatocellular carcinoma (HCC) in adolescents . CurrentCavernous transformation of the main portal vein is classified as (evidence of) tumour thrombus.Extrahepatic disease is a rare situation, occuring in less than 5% of patients with HB. Simple ascites is not considered extrahepatic disease.Multifocal tumours are present in 20% of patients with HB.Rupture of the tumour during surgery is not considered tumour rupture.Lymph node metastases are uncommon in HB and require pathologic confirmation.HB metastastses occur most commonly to the lung; this happens in 20% of HB cases. Biopsy is not necessary for diagnosis, because it is unusual for other lesions to mimic metastases.Tumours close to hilar structures leading to compression of local structures may lead to classification challenges. Tumours that are pushing vascular structures aside may cause pressure changes that can mimic invasion on imaging .Good knowledge of liver anatomy and high quality imaging  are essential to assess resectability. Since its development in 1992, the PRETEXT (PRETreatment EXtent of Disease) system is used for planning of liver surgery, to predict tumour resectability and to predict prognosis. PRETEXT is based on segmental anatomy of the liver  approach has been laparotomy at diagnosis with an upfront resection in all patients. According to the International Paediatric Liver Tumour Study Group ‘SIOPEL’, the convention was to treat all patients with neoadjuvant chemotherapy and perform delayed resection . In orderesection at diagnosis is recommended for tumours that are categorized as very low risk. This applies to the following cases: PRETEXT I and II, M-, resectable at diagnosis (VPEFR-), and additionally in PRETEXT II: age < 8 years, AFP > 100. For other tumours, timing of resection is less straight forward. Surgical resection is performed after satisfactory evaluation based on imaging after neoadjuvant chemotherapy. An upfront resection is recommended only when a segmentectomy or nonextended hemihepatectomy with at least 1 cm margin is possible on middle hepatic vein and/or main portal vein division, and there is no concern for macrovascular involvement [Currently olvement , 5.Both knowledge of liver anatomy and experience in liver surgery are absolutely necessary to decide on the type of liver resection. Anatomic resections (based on Couinaud’s division of liver anatomy) are generally recommended  Fig. . The typLiver mobilisation. Triangular ligament ligated and transected, and the falciform ligament is incised until the subdiaphragmatic inferior vena cava (IVC) is reached. To mobilise the right lobe, the right triangular ligament is incised. On the left side, the left triangular ligament is transected.Intraoperative ultrasonography. It is very important to evaluate the resection margin from the point of view of oncological safety, particularly in the case of extensive tumour or multifocal lesions. It allows to reveal liver anatomy, locate lesions, and define tumour connections with portal pedicles and hepatic veins.Inflow control (hilar phase) Fig. . The artOutflow control (venous phase). Extrahepatic isolation of the hepatic veins is possible in most cases. This technique allows for good control in case of haemorrhage during the next phase. In some situations hepatic veins can be transected during parenchymal transection. This particularly applies to the middle hepatic vein (MHV), as it is often involved in the surgical margin.Parenchymal transection. After inflow and outflow control, a clear line of ischemia is visible and parenchymal dissection is proceeded along this line. Methods of parenchymal transection are, inter alia: (1) finger or clampfracturing the tissue, (2) harmonic scalpel, (3) ultrasonic energy , (4) radiofrequency energy , (5) water-jet dissection, (6) the application of surgical stapler. To minimize blood loss the Pringle maneuver  can be applied. It is worth remembering that intermittent clamping is better tolerated by the liver remnant than continuous occlusion . When peOozing control. After cutting the liver surface it can be secured with bipolar coagulation, LigaSure, argon beam, clips, and/or various topical hemostatic agents Fig. .It is well-known (and mentioned above), that the goal of surgical resection is to achieve complete tumour clearance, however, the healthy liver tissue margin required in paediatric HB is a matter of debate . The traPatients must be carefully selected.Specific training is needed and the accompanying learning curve should be taken into account .The rules of safe oncological surgery must always be followed.Over the last decade, laparoscopic liver resections for paediatric hepatic tumours have been successfully performed, but most laparoscopic hepatectomies reported are case presentations and small case series of nonanatomical resections for small, peripheral and usually benign, isolated lesions . There iThis new treatment option for patients with marginally resectable liver tumours was introduced in 2007, but formally described only in 2011 . As largFirst operation: (1) portal vein ligation, (2) in situ splitting of the liver parenchyma , (3) eventual clearance of the FLR from satellite neoplastic lesions in case of multifocal tumour.Second operation: (1) transection of the hepatic artery and the bile duct, (2) transection of the hepatic vein, (3) appropriate part of the liver is removed.Rapid hypertrophy of the future liver remnant—47–93% within 7–14 days .Increased likelihood of possible R0 resection in selected cases.Avoidance of postoperative liver failure.Reduced the interval between the 2 surgeries, and thus less chance of tumour progression.ALPPS may promote tumour growth, but the mechanism is unclear  and therRapid hypertrophy does not always correlate with sufficient liver function .Fortunately, children tolerate major resections better than adults (in children the FLR should be at least 25%), and therefore ALPPS is rarely necessary in this age group. The first (and the last so far) series of paediatric patients treated with ALPPS was presented by Wiederkehr et al. in 2015. There were two patients with HB, 1 with HCC, 1 with RMS, and 1 with FNH .Cases of HB warranting extreme resections and vascular reconstructions, should be carried out in transplant centres of excellence in paediatric liver surgery.We recommend a combination of a surgeon well experienced in liver surgery and a liver transplant surgeon in the operating team for such HB cases.Cases of HB involving three or four sectors of the liver (POSTTEXT III–IV) or the hilum of the liver may be cured by an extended (right or left) liver resection or a total hepatectomy and LTX including partial hilar vessel resection and reconstruction , 35. Whe10–20% of all HB cases require liver transplant (LTX) Indications and contraindications for liver transplant for hepatoblastoma are presented in Table 6Locally advanced tumours are a challenge for surgeons.Some reports have questioned the role of salvage LTX , suggesting that it is connected with inferior survival when compared with primary LTX (80% vs. 30–40%), although there are some conflicting studies –47.It is important to note that hepatoblastoma patients who present with extrahepatic or metastatic active disease at diagnosis that fully clears with chemotherapy and/or surgery are still candidates for transplantation.Survival rates after primary transplantation are excellent: about 80–85% 5 years OS .However, it should be borne in mind that LTX has its own “dark side”: a relatively high complication rate leading to comorbidity and the need for immunosuppressive drugs and their side effects such as secondary neoplasms.In certain cases, it may represent quite a challenge to decide whether to perform an extreme or complex resection or have the patient undergo a transplant . ContinuSpontaneous rupture of HB is very rare and occurs in 3–9% of HB . The diaChildren with resectable HB and synchronous lung metastases: pulmonary metastasectomy should be performed after the resection of the primary tumor, because the control of primary HB is associated with improved outcomes. After hepatectomy, pulmonary metastasectomy is usually preceeded by 1 or 2 chemotherapy courses.Patients with an indication for LTX: pulmonary metastases that persist after chemotherapy should be resected before transplantation.The most common location of distant metastases in HB is the lung (occurring in 20% of cases). The timing of metastasectomy is currently under discussion –52. The An open question is whether chemotherapy alone is enough to clear the lungs in patients undergoing LTX. The potential need for surgical exploration to confirm the clearance of metastases is discussed in the literature .Liver resection is a high-risk but “safe” operation with a mortality rate less than 5% in experienced hands , 46Morbidity rates remain high and range from 4 to 56% –55When the tumour remains unresectable after chemotherapy various therapeutic approaches may be applied. These include liver transplantation, extreme resection, staged hepatectomy (see ALPPS section), and/or interventional radiology procedures  , 57. Rel


The viscosity of the gel was relatively stable at room temperature (27 °C) for one week. In a suspension containing 10% sand , the settling velocity of proppant particles was 1.15 cm h−1. In addition, we detected that the critical micelle concentration of this gel was approximately 0.042 wt%. The viscosity could be reduced to <5 mPa·s at 60 °C within 1 h when 6.0% crude oil was present, and oil displacement experiments showed that the broken fracturing fluid can enhance the oil displacement rate up to 14.5%. This work may facilitate research on fracturing fluids and oil recovery.In this paper, a betaine-based gel containing 2.0% erucamide propyl betaine (EAPB), 0.5% oleic acid amide propyl betaine (OAPB), and 0.1% KCl was prepared for use as a fracturing fluid. The performance evaluation showed that KCl may improve the temperature resistance and increase the viscosity of the optimized fracturing fluid. At 80 °C, the apparent viscosity of the viscoelastic surfactant (VES)-based fracturing fluid was approximately 50 mPa·s. Furthermore, the gel had high shear resistance, good viscosity stability, and high sand-carrying performance. After being sheared at 170 s The exploitation of tight reservoirs becomes more important with the depletion of conventional high-permeability reservoirs. However, due to the low permeability nature of the tight reservoirs, extracting crude oil from these kinds of reservoirs is difficult. Hydraulic fracturing is a commonly used well stimulation technology to increase oil and gas production  and is rHowever, conventional polymer fracturing fluids, such as guar gum (GG), have been used due to their ability to regulate the rheological properties and enhance the viscosity of aqueous solution. However, the swelling rate of GG is slow, and its efficiency is easily degraded by microorganisms . FurtherAccording to the above situation, the EAPB and OAPB were selected as the primary agents of a VES-based fracturing fluid in this paper. Furthermore, the development of new oil displacement technologies to improve the recovery of oil fields has become a hot issue , and sur2O (AR) was purchased from Tianjin Chemical Reagent Factory, China and KI (AR) was purchased from Tianjin Kemio Chemical Reagent Co., Ltd., Tianjin, China. All chemicals were used as received without further purification.Oleylamine propyl betaine (40 wt%) (OAPB) was purchased from Huainan Huajun New Material Technology Co., Ltd., Beijing, China. Erucamide propyl betaine (40 wt%) (EAPB) and (40 wt%) (EAPS) were purchased from Shanghai Shengxuan Biochemical Co., Ltd., Shanghai, China. KCl (AR) was purchased from Tianjin Damao Chemical Reagent Factory in China. KBr (AR) was purchased from Tianjin Baishi Chemical Co., Ltd., Tianjin, China. KF·2HA six-speed rotary viscometer  was used to evaluate the ability of EAPB, EAPS, and OAPB to enhance the viscosity of the surfactant solution with various dosages .2O, KCl, KBr, and KI). The viscosity was measured at various concentrations and temperatures to find the optimized salts. After screening surfactants and salts, an optimized formula of the VES-based fracturing fluid was obtained.Based on the results of surfactant screening, the selected surfactant was mixed with each of the salts (KF·2H−1) for a period of time. Subsequently, it was measured at 60 °C for shear rate ranges of 170 s−1. Besides, the effect of constant shearing (170 s−1) on the viscosity of the optimized VES-based fracturing fluid would also be investigated at various temperatures. The sample was performed on a Physica MCR 301  rotational rheometer equipped with a searle-type concentric cylinder geometry CC27(ISO3219) [The viscosity of the optimized VES-based fracturing fluid was measured at different conditions to evaluate the shear resistance properties. Firstly, the fracturing fluid was measured at a constant temperature and shear rate  .−3) were mixed with the optimized fracturing fluid in a beaker and then placed into a graduated cylinder at constant temperature conditions. The settling time for the proppant to be deposited on the cylinder’s bottom was recorded as the settling velocity.In this section, a certain amount of proppant particles , and the critical micelle concentration (cmc) was determined from the inflexion of the surface tension . Further−3) and then placed in a desiccator at 60 °C for 18 h. Then, 8 g oil-treated sand was mixed with 135 mL fracturing fluid and placed in a de-oil apparatus at 80 °C. The experiment was performed in a water bath. The picture below shows the de-oil apparatus  to find a suitable salt to increase the viscosity of the VES solution. In this section, 2% EAPB and 0.5% OAPB were mixed with other potassium halides .According to −3 and particle size of 0.45 mm were employed to conduct the proppant suspending performance test. The content of the proppant particles in the optimized VES-based fracturing fluid was set at 10, 20, and 30%, respectively. The process of the proppant settling is shown in −1, respectively.The sand-carrying performance is an important index to evaluate the property of fracturing fluid. In this experiment, the proppant particles  with a dThe viscosity of viscoelastic surfactants will decrease rapidly when they encounter hydrocarbon materials , which iThe 2% EAPB + 0.5% OAPB + 0.1% KCl mixture solution was diluted to different concentrations, and the change in concentration of EAPB was used as the diluted solution concentration. As can be seen from It can be seen from In this paper, to provide an environmentally friendly fracturing fluid formula for low permeability oilfield development, a viscoelastic surfactant gel containing 2% EAPB, 0.5% OAPB, and 0.1% KCl was prepared. The performance evaluation showed that the presence of KCl may improve the temperature resistance and increase the viscosity of the optimized fracturing fluid. Furthermore, the viscoelastic surfactant gel had high shear resistance and high sand-carrying performance. The broken gel solution was used in oil displacement tests, and the results showed that the oil displacement rate could reach 14.5% with a concentration of 0.3%.


Ore precipitation in porphyry copper systems is generally characterized by metal zoning (Cu–Mo to Zn–Pb–Ag), which is suggested to be variably related to solubility decreases during fluid cooling, fluid-rock interactions, partitioning during fluid phase separation and mixing with external fluids. Here, we present new advances of a numerical process model by considering published constraints on the temperature- and salinity-dependent solubility of Cu, Pb and Zn in the ore fluid. We quantitatively investigate the roles of vapor-brine separation, halite saturation, initial metal contents, fluid mixing and remobilization as first-order controls of the physical hydrology on ore formation. The results show that the magmatic vapor and brine phases ascend with different residence times but as miscible fluid mixtures, with salinity increases generating metal-undersaturated bulk fluids. The release rates of magmatic fluids affect the location of the thermohaline fronts, leading to contrasting mechanisms for ore precipitation: higher rates result in halite saturation without significant metal zoning, lower rates produce zoned ore shells due to mixing with meteoric water. Varying metal contents can affect the order of the final metal precipitation sequence. Redissolution of precipitated metals results in zoned ore shell patterns in more peripheral locations and also decouples halite saturation from ore precipitation. Ore precipitation in porphyry-centered magmatic-hydrothermal systems generally produces base metal zoning patterns that transition upwards and outwards from proximal Cu–Mo to distal Zn–Pb–Ag, with variable lateral extents of up to 8 km2. Experimental studies and thermodynamic modeling indicate that cooling of magmatic fluids accompanied by fluid-rock interaction is a first-order control on metal precipitation and zonation patterns, resulting from different solubilities of the respective metals along fluid pathways4. The timing and role of incursion of external fluids for ore formation are debated, with some studies indicating that fluid mixing may already occur during primary mineralization and/or that later circulation can cause metal redistribution8.Porphyry copper systems are our main resources for the global supply of Cu and in addition contain a large variety of other metals at economic or sub-economic grades10. Fluid inclusion data suggest that fluids exsolving from granitic to granodioritic intrusions in the upper crust yield bulk salinities of 5 to 15 wt% NaClequiv11. Depending on the fluid salinity, temperature, pressure and the metal content of the parental magma, metal contents of the primary single-phase magmatic fluid vary between 20 and 20,000 ppm Cu (mean 2660 ppm), 10 and 4500 ppm Pb (mean 330 ppm), as well as 20 and 6500 ppm Zn (600 ppm)12.Metals such as Cu, Pb and Zn in porphyry systems are predominantly transported by hydrothermal fluids as chloride complexes under elevated temperatures and rather acidic conditions13, with apparent Cu partitioning into the vapor phase now being explained as an artifact due to post-entrapment diffusion into vapor inclusions15. However, the respective roles of the vapor and brine phases for mineralization in porphyry Cu systems remain debated, because mass balance considerations suggest that phase separation at depth produces larger amounts of vapor than brine17 and some of the ascending vapor phase can condense into a liquid phase during ascent and cooling20. Geophysical evidence and numerical modeling further suggest that brine lenses form beneath active and dormant volcanoes21, which inspired propositions that these metal-rich hypersaline fluids with Cu contents of up to 7000 ppm stored at depth may have an economic potential22. However, it remains unknown whether such brine accumulations are long-lived or rather transient features, with both scenarios being permissive in different set-ups in numerical simulations23.This primary fluid exsolved from the magma phase-separates upon ascent due to decompression into a low-salinity vapor and a hypersaline liquid (brine) phase. Fluid inclusion analyses and experimental studies show that base metals like Cu, Pb and Zn preferentially partition into the brine phase24 or post-entrapment modifications25. Halite saturation also occurs in numerical simulations of porphyry systems using different models and set-ups27. The transition from liquid–vapor stability toward vapor-halite stability of the ascending fluid would be accompanied by an abrupt decrease and eventually disappearance of the liquid mass fraction. This process would lead to an abrupt decrease in the capacity of the fluid to carry metals in solution, which could lead to base metal precipitation24, albeit further transportation as dispersed particles during potential eruptive processes at these conditions may also be possible.Furthermore, a large number of ore-stage brine inclusions homogenize by halite disappearance, which either reflects saturation in solid halite2O–NaCl fluids in porous media28. These numerical models can simulate the evolution of the mineralization and have provided insightful results for specific ore-forming processes29, but still rely on some simplifications. In particular, capabilities for full reactive-transport modeling including chemical speciation, pH and redox conditions as well as the role of ligand complexing for metal transport in the formation of high-temperature ore deposits are still under development. Previous work using the software CSMP++ focused on the physical hydrology and implemented a simple proxy for temperature-dependent Cu enrichment29. These numerical simulations suggest that the dimensions of the resulting ore shell depend on the interplay between magmatic fluid release, meteoric water convection and dynamic permeability distributions, reproducing typical copper ore bodies with bell-like shapes and lateral extents of 1–3 km 23. Recent simulations of clastic-dominant (CD-type) Pb–Zn deposits using the same model further considered the remobilization of Pb and Zn by circulating heated fluids, but based their parameterizations only on the temperature dependence of metal solubility30. These models do not yet consider the effect of fluid salinity and metal partitioning between fluid phases.Quantifying the dynamic behavior of mass and heat transfer in porphyry systems can be approached by numerical simulations using models that can handle high-temperature multi-phase flow of H12, similar but not identical to parameterizations in the simulations of Blundy, et al.22, which also introduced temperature- and salinity-dependent Cu solubilities and partitioning during phase separation to their model. The addition of Pb and Zn provides a further constraint for the hydrology at the porphyry-epithermal transition and an opportunity to test whether metal zoning with variable lateral extents can be explained by simple cooling along characteristic fluid pathways. Furthermore, we use the remobilization functionality introduced by Rodríguez, et al.30 to constrain its impact on base metal ore shells related to porphyry systems. To date, a full representation of fluid-rock interactions at these conditions is not yet possible, because it would require an internally consistent thermodynamic model that can reliably cover high-temperature, low-density fluid phases. However, the new developments mark a step forward towards more geological realism by including additional geochemical constraints. We use this augmented numerical model to investigate the role of phase separation, brine formation, halite saturation, fluid mixing and remobilization as first-order controls of the physical hydrology on precipitation mechanisms of base metals in porphyry systems.For this study, we therefore developed a new parametrization, which considers individual temperature- and salinity-dependent solubilities for Cu, Pb and Zn. The used metal solubilities are based on calculations of Kouzmanov and Pokrovski31. Using a realistic expression of the nonlinear fluid properties  and the physical separation of fully miscible multi-phase fluids , the model can perform compressible fluid flow at temperatures up to 1000 °C and pressures up to 500 MPa33.We calculate fluid flow with a continuum approach for porous media using the Control Volume Finite Element Method (CVFEM) numerical scheme which is implemented in the Complex Systems Modeling Platform (CSMP + +)34. Saline fluids may further precipitate a solid halite phase Given the Darcy velocity The conservation of fluid mass is calculated as26 and is based on the following assumptions: (1) a depth-dependent background permeability profile, (2) a near-critically stressed brittle crust and a consequential failure criterion for fractures at near-hydrostatic fluid pressure conditions, (3) an increasingly ductile behavior through heating, leading to a reduction in permeability and differential stress, causing failure criteria at near-lithostatic fluid pressures (with the transition from brittle to ductile starting at 360 °C), (4) a pressure-dependent permeability increase, which counteracts the temperature-dependent permeability decrease and (5) an incremental increase in permeability in response to hydraulic fracturing by as much as two orders of magnitude if fluid pressures exceed the local stress-state-dependent failure criterion. Further details on the numerical approach and benchmark solutions are given in Weis26 and Weis, et al.31.The permeability The main focus of this study is to advance the numerical model for porphyry Cu systems with respect to (i) the solubility of Cu, Pb and Zn in the ore fluid in dependence on temperature and salinity, (ii) the partitioning of these metals between vapor and liquid, (iii) the metal transport by ore fluids, (iv) varying metal concentrations of the primary magmatic fluid and resulting metal enrichment potential and (v) remobilization of previously precipitated metals.12 for elevated temperatures and salinities witheq in the fluid, a00,Cu = −9.215, a01,Cu = 0.1126, a10,Cu = 0.03875, a20,Cu = −3.209 ∙ 10–5, a11,Cu = −1.213 ∙ 10–4, a00,Pb = −3.269, a01,Pb = 0.1068. a10,Pb = 0.01408, a20,Pb = −5.685 ∙ 10–6, a11,Pb = −7.534 ∙ 10–5, a00,Zn =  − 2.234, a01,Zn = 0.1245, a10,Zn = 0.01313, a20,Zn = −4.914 ∙ 10–6, a11,Zn = −1.367 ∙ 10–4. The resulting expressions are shown in Fig. equiv as they are not yet constrained by the data from Kouzmanov and Pokrovski12. For the time being, we use extrapolations to higher temperatures and salinities with this parameterization, which leads to higher solubilities in these ranges and is generally in line with other studies on Cu contents in hydrothermal fluids14. However, metal precipitation is expected to rather occur within the data range covered in Kouzmanov and Pokrovski12. Metals are completely dissolved in the fluid phases if i) Metal solubilities are calculated using temperature- and salinity-dependent functions for the individual metals mentclass2pt{minimii) The total metal concentrations, Analytical and experimental data indicate that metal partitioning between liquid and vapor depends on the salinity of the respective phase. We approximate this observation by first calculating the solubility of the individual phases with their respective salinities and then calculate the solubility of the bulk fluid. If the fluid is saturated in a respective metal, we partition the concentration according to the respective phase solubilities, leading to a salinity- and mass-dependent partitioning. If the bulk fluid is undersaturated in a metal, we use the same degree of partitioning by assuming the same degree of undersaturation in both phases.D, and a source term iii) We introduce Cu, Pb and Zn as tracers to the mass conservation asmentclass2pt{minimmentclass2pt{minim29, the primary magmatic fluid contains 500 ppm Cu, which is based on measurements of intermediate density (ID) fluid inclusions in porphyry Cu systems and experimental studies. The Pb concentrations of 330 ppm as well as Zn concentrations of 600 ppm refer to mean values of ID fluid inclusions originating from numerous porphyry Cu deposits12. To study the effect of the initial metal concentrations and metal zoning, we also performed simulations with lower initial Zn concentrations of 330 ppm (same as Pb) and Pb concentrations of 33 ppm. As a modeling proxy for ore grade distributions, we calculate metal enrichment potentials asiv) To ensure the best possible comparability with other numerical modeling studiesv) In a first suite of simulations, we consider that metals only accumulate over time due to metal precipitation from oversaturated fluids. As an additional functionality, we include remobilization of previously precipitated metals if undersaturated hydrothermal fluids flow through volumes containing metal precipitates. We assume that fluids can remobilize metals until either the fluids are saturated or the respective volume is fully depleted in the respective metal. This functionality for remobilization also covers the potential case that Cu, Pb and Zn are temporarily stored as Cl-complexes together with solid halite and also get subsequently redissolved by later ingression of less saline fluids. Further downstream, the metals can get reprecipitated as soon as the fluids become oversaturated again.37, but has the potential to be extended to higher temperatures once robust thermodynamic datasets are available. For the time being, we have to use the simplifying assumptions mentioned above and critically consider them when evaluating the modeling results.Although we account for temperature- and salinity-dependent metal solubilities, the current model cannot resolve the effect of chemical speciation  on metal transport, partitioning, precipitation and remobilization. Full reactive-transport has only been well established for less complex hydrothermal systems forming at lower temperatures−2 km3/y29. Two radial factors (0.25 and 0.5) were applied resulting in a theoretical magma volume of ~ 47 km3 and ~ 95 km3, respectively. This is in line with a presumed minimal volume of 50 km3 proposed to form porphyry Cu deposits38. An approximately doubled magma volume is also accompanied by an approximately doubled fluid release rate, with primary magmatic fluids assumed to be expelled exclusively from the cupola region of the magma chamber  or ~ 95 km3 (simulation 2); initial fluid concentrations of 500 ppm Cu, 330 ppm Pb, and 330 ppm Zn; without metal remobilizationMagma volume and fluid release rate: magma volume of ~ 47 km3; initial fluid concentrations of 500 ppm Cu, 33 ppm Pb, and 600 ppm Zn (simulation 3); without metal remobilizationMetal contents: magma volume of ~ 47 km3 (simulation 4) or ~ 47 km3 (simulation 5); initial fluid concentrations of 500 ppm Cu, 330 ppm Pb, and 330 ppm Zn; with metal remobilizationRemobilization: magma volume of ~ 95 kmWe present results from the five most representative simulations to study the influence of three key parameters:26. The fluid release rate is proportional to the dimensions, water content and cooling rate of the magma reservoir. In simulation 1, which assumes a reservoir volume of ~ 47 km3 , the hydrologic divide is located at a depth level of ~ 2.2 km, ~ 2.1 km and ~ 3.6 km after 10, 50 and 100 kyrs, respectively  results in a hydrological divide that is located at comparatively shallower depths at ~ 1.8 km, ~ 1.9 km and ~ 3.1 km after 10, 50 and 100 kyrs, respectively  and the Cu content (in ppm) of the fluid Fig. . The magHigh-pressure conditions enable the further ascent of the heavy brine within the overpressured inner domain and therefore a brine-dominated zone develops atop the hydrological divide after the pressure-drop to near-hydrostatic values Fig. . In simuIn the absence of halite saturation, as in simulation 1, the brine zone is enriched in Cu Fig. b and ore2. Ore precipitation is related to the timing of saturation in the respective metals, which depends on the metal contents in the input fluid. In simulation 3, we reduce the initial Pb content to 33 ppm and increase the initial Zn content to 600 ppm. Regarding the isoline of maximum Zn saturation from simulation 1, higher Zn contents only cause minor deviations towards greater depths  as a proxy for a potential polymetallic ore shell.In Fig. Considering initial fluid metal contents of 500 ppm Cu, as well as 330 ppm Pb and Zn (simulation 1), the highest total rock metal contents are found at the intersection of the Cu and Pb shells and thus indicate a dominance of Cu and Pb in the overall metal content of the rock  follows the parameterization of metal solubilities used for this study and is also detectable in natural ore bodies41, especially when considering the strong overlap of the Pb–Zn mineralized zones43. Other porphyry-related base metal deposits show a zonation from Cu to Zn to Pb, which is more common44 and could be reproduced if the initial fluid is Pb-poor.The simulations with lower fluid release rates suggest that metals are precipitated from a two-phase vapor-brine fluid and develop zoned ore shell patterns similar to typical observations in porphyry Cu systems2 Figs. , 7. Meta2 Figs. b by admi2 Figs. a. Our si45. However, this two-phase fluid is undersaturated in Cu, because solubility increases non-linearly with salinity according to data provided by Kouzmanov and Pokrovski12. Depressurization and cooling at the hydrological front can first increase the amount of vapor within the two-phase zone, leading to near-saturation Cu contents. However, once fluid pressures reach near-hydrostatic values, the high-density brine phase dominates, leading to Cu contents well above the ones of the input fluid, but again very low Cu saturations. Cu precipitation can thus only be reached by further cooling and/or brine dilution.The simulations show that the metal content and solubility of the single-phase magmatic input fluid is a limiting factor controlling ore precipitation, in particular for Cu. During ascent and phase separation of the nearly Cu-saturated primary magmatic fluid, Cu contents in the bulk two-phase fluid will be considerably increased due to preferential partitioning into the brine phase and faster ascent of the vapor phase. Our modeled concentrations are comparable to values measured in brine inclusions20.The simulations further illustrate that phase separation is a temporally and spatially continuous process, which makes the debate about whether the vapor or the brine phase transport and precipitate the bulk of the Cu ore difficult. Vapor and brine ascend together, albeit at different velocities, and are at all times fully miscible according to given TPX-dependent phase relations. Hence, even if Cu preferentially partitions into the brine phase and S into the vapor phase, both elements are likely to still be available in the two-phase mixture to form Cu sulfide minerals in case of oversaturation24 or result from post-entrapment modifications25 remains debated, and our new modelling results can only confirm that it is a possible but not an inevitable ephemeral feature.Halite saturation can cause co-precipitation of Cu, Pb and Zn Fig. e, f. GivEnabling redissolution of already precipitated metals in dependence on their calculated solubility and abundance decouples halite saturation from ore precipitation and also results in the formation of a zoned ore shell pattern (simulation 4, Figs. 23. The dimension of the peripheral zoning with lateral extents of up to 8 km generally fits with observations of some porphyry-epithermal systems 46, in particular when also considering low-grade metal contents (Fig. 1. Distinct epithermal mineralization events may thus require a distinct fluid event or pulse that could lead to higher fluid temperatures in the epithermal regime.The simulations presented in this study produced wider and more horizontally stretched Cu ore bodies than typically observed in high-grade porphyry Cu deposits. However, previous studies have shown that limiting the extent of more vertically extended ore shells to 1–3 km can be achieved by increasing the host rock permeability in the model parametrization22, but diverge in the residence times of metal-enriched magmatic brines formed by phase separation. Whereas Blundy, et al.22 simulate long-lived brine lenses and propose an economic potential for metal extraction, our simulations suggest a rather transient occurrence of hypersaline brine layers that become diluted by meteoric water incursion and transported out of the system. Fluid mixing is enhanced in our model, because it includes a magma reservoir at 5 km depth as a driver for external convection, whereas Blundy et al.22 single out the effect of magmatic volatile injection. The two models also use different parameterizations of the host rock permeability. Hence, the residence times of magmatic brines may depend on permeability evolution and the size and depth of the underlying magma reservoir—parameters that so far are typically not well constrained in both fossil and active systems.Our simulations share many similarities with the simulations of Blundy, et al.12. Lowering the pH value from 5 to 4, for example, may increase the metal contents and solubilities of the single-phase fluid by one order of magnitude for Cu and two orders of magnitudes for both Pb and Zn12. Such complexities will only be resolvable once full reactive-transport modeling for magmatic-hydrothermal systems should become possible. However, our simulations can already be used to gain new insights into the feasibility of ore formation by cooling and dilution of magmatic fluids.The modeled physical hydrology and its geochemical implications rely on a number of simplifications, with some being intentional to reduce the complexity of the system while others are due to a lack of adequate data or numerical tools. Our modeling efforts are still restricted by limitations in the formulation of physical and chemical processes, e.g. the dynamic permeability evolution at brittle and ductile conditions, fluid-rock reactions influencing variations in pH, redox conditions, sulfide availability, mineral chemistry and species of aqueous fluids which can have a significant effect on metal solubilitiesOur simulations can reproduce the general pattern of metal zoning with lateral extents of up to several kilometers and Pb–Zn mineralization being peripheral to Cu-mineralization for scenarios that avoid halite saturation by cooling and dilution of magmatic brines due to significant incursion of meteoric water.The vapor and brine phases of the two-phase ore-stage fluid ascend together with different residence times, but still in contact with each other at all times. The brine phase becomes enriched in base metals due to preferential partitioning, but remains metal-undersaturated even for saturated primary single-phase input fluids if solubilities increase non-linearly with fluid salinities.Our simulations were able to produce distinct ore shells, especially when the model setups accounted for potential remobilization of metals followed by reprecipitation. Saturation of solid halite can lead to high-grade deposits with simultaneous precipitation of ore metals, which is in contrast with characteristic vein types at the deposits, but therefore emphasizes the importance of remobilization for future modeling approaches.Brine lenses underneath stratovolcanoes are transient features, leading to direct ore formation rather than longer-term storage of a metal-rich brine phase.Future simulations should include improved thermodynamic models, comprising pH, redox, chloride and bisulfide complexing to provide more detailed insight into the relevant geochemical processes including the role of fluid-rock reactions.We investigated the role of phase separation, brine formation and remobilization on base metal precipitation in porphyry Cu systems using an advanced numerical model that incorporates published temperature- and salinity-dependent metal solubilities. Based on these simplified parameterizations, the simulations suggest some first-order feedbacks between physical hydrology and geochemistry:


Drilling fluid is the blood of drilling engineering. In the polar drilling process, the ultra-low temperature environment puts high demands on the rheological performance of drilling fluids. In this paper, the effects of temperature, ice debris concentration and weighting agent on the rheological properties of drilling fluids were studied. It was found that the lower the temperature and the higher the ice debris concentration, the higher the drilling fluid viscosity, but when the ice debris concentration was below 2%, the drilling fluid rheology hardly changed. Secondly, the low temperature rheological properties of drilling fluid were adjusted by three different methods: base fluid ratio, organoclay, and polymers . The results showed that the base fluid rheological performance was optimal when the base fluid ratio was 7:3. Compared with polymers, organoclay has the most significant improvement on the low temperature rheological performance of drilling fluid. The main reason is that organoclay can transform the drilling fluid from Newtonian to non-Newtonian fluid, which exhibits excellent shear dilution of drilling fluid. The organoclay is also more uniformly dispersed in the oil, forming a denser weak gel mesh structure, so it is more effective in improving the cuttings carrying and suspension properties of drilling fluids. However, the drilling fluid containing polymer additives is still a Newtonian fluid, which cannot form a strong mesh structure at ultra-low temperatures, and thus cannot effectively improve the low-temperature rheological performance of drilling fluid. In addition, when the amount of organoclay is 2%, the improvement rate of the yield point reaches 250% at −55 °C, which can effectively improve the cuttings carrying and suspension performance of drilling fluid at ultra-low temperature. However, 99% of the area is covered by ice, and the average thickness of the ice cap is 1829 m. Antarctica is rich in mineral resources, with 220 types of proven minerals, including coal, oil, natural gas, diamond, and uranium of strategic importance. It is estimated that the current oil reserves in the Antarctic region are about (7.95–15.90) × 109 m3, with natural gas reserves of about (3–5) × 1012 m3, and the potential resources of hydrates at the land edge are about (4.7–7.8) × 1013 m3. However, due to the low Antarctic surface temperature (−60 to −50 °C) [In recent years, with the increasing national demand for energy, oil and gas exploration has gradually expanded to deep land, deep sea, and complex strata, such as polar regions. Antarctica is rich in resources, with an area of 14.5 million kmAt present, research scholars have conducted a lot of studies on the rheological properties of drilling fluids under high temperature, high pressure ,4,5,6, aThe rheological performance of drilling fluids at ultra-low temperatures is one of the key issues in the polar drilling process. However, when there are deficiencies in the rheological performance regulation of the drilling fluid, the main problems are low yield point and poor suspension ability. These problems tend to make the drilling fluid carry the cuttings unfavorably, causing problems, such as cuttings accumulation at the bottom of the well, abnormal agitation pressure, and equivalent circulation density, leading to downhole accidents and ultimately affecting drilling costs. The excellent rheological performance is directly related to the efficiency of drilling fluid in carrying cuttings, and indirectly affects the drilling speed. However, there are no reports on the rheological performance of polar drilling fluids at home and abroad. Therefore, in view of the above problems, this paper has studied the low temperature rheology law of polar drilling fluid and the rheology adjustment methods. In addition, the influence mechanism of various adjustment methods on the rheology of drilling fluids was also analyzed. It has certain reference significance for further polar drilling.Following the investigation into the research status of polar ultra-low temperature drilling fluids, the influence law of temperature, concentration of ice debris, and weighting agent addition on the rheology of polar drilling fluids (aviation kerosene) were explored in depth.Temperature is an important factor affecting the rheology of drilling fluids. The influence of temperature on the rheology of aviation kerosene drilling fluid is revealed by exploring the change of its viscosity at different temperatures.Experimental studies showed that the viscosity of drilling fluid gradually increased as the temperature gradually decreased in the range of −55 °C to −5 °C, with an obvious low-temperature thickening phenomenon . The addition of ice debris is 0%, 2%, 4%, 6%, and 8%, respectively.The experimental study found that the viscosity and yield point of drilling fluid gradually increased with the increasing concentration of ice cuttings . When th3, while the density required for polar drilling fluid should be 0.92–0.95 g/m3. Therefore, it is necessary to increase the drilling fluid density by adding a weighting agent. In addition, the smaller the viscosity of the required drilling fluid, the better the drilling speed.The experimental study found that the density of aviation kerosene-based fluid is 0.78 g/cm3), and the results are shown in To investigate the effect of the weighting agent addition on the rheological properties of aviation kerosene drilling fluid, HCFC-141b weighting agent was used to adjust to the different densities. The viscosity-temperature characteristics of the aviation kerosene drilling fluid were studied at different weighting densities  to explore the effect of the base fluid ratios on the drilling fluid rheology at different temperatures. The experimental results are shown in It can be seen from According to In conclusion, the yield point of drilling fluid with a base fluid ratio of 7:3 and 6:4 is the same at an ultra-low temperature (≤−35 °C), but the viscosity of the base fluid at 7:3 is smaller at an ultra-low temperature, which is more suitable for Antarctic drilling requirements. Therefore, when the base fluid ratio is 7:3, the rheological property of the drilling fluid is the best.Organoclay is commonly used as a rheology modifier for oil-based drilling fluids ,22 and hTo study the effect of organoclay on the rheology of ultra-low temperature drilling fluid, organoclay  and amide emulsifier (Hanke emulsifier) were added on the basis of 7:3 base fluid ratio to formulate ultra-low temperature drilling fluid, and the effect of different concentrations of organoclay on the rheological performance of the drilling fluid was investigated separately.The experimental study found that the apparent viscosity, plastic viscosity, and yield point of the drilling fluid showed a gradual increase with the increase of organoclay concentration at a specific temperature . At a ceAccording to Dimeric AcidDifferent concentrations of dimeric acid  were added to the base fluid of drilling fluid to explore the effects of different concentrations on the apparent viscosity, plastic viscosity, and yield point of the drilling fluid at −55 °C~−5 °C.It was found that the apparent viscosity, plastic viscosity, and yield point of the drilling fluid showed a gradual increase with increasing dimeric acid concentration at the same temperature . This ma2.PolymethacrylateIn this section, the effects of different concentrations of polymethacrylate  on the apparent viscosity, plastic viscosity, and yield point of the drilling fluid were investigated at −55 °C to −5 °C.It was found that the apparent viscosity, plastic viscosity, and yield point of the drilling fluid showed a gradual increase with increasing polymethacrylate concentration at the same temperature . This ma3.Ethylene Propylene CopolymerDifferent concentrations of ethylene propylene copolymer  were added to the drilling fluid to investigate the effects of different concentrations of ethylene propylene copolymer on the apparent viscosity, plastic viscosity, and yield point of the drilling fluid under the conditions of −55 °C~−5 °C.The experimental study found that the apparent viscosity, plastic viscosity, and yield point of drilling fluid showed a gradual increase with the increase of ethylene propylene copolymer concentration at a specific temperature . The dri4.Vinyl ResinThe effects of different concentrations of vinyl resin  on the apparent viscosity and plastic viscosity of drilling fluid at specific temperatures and the relationship between the viscosity of drilling fluid and temperature at specific additions of vinyl resin were investigated, respectively. The experimental study found that the apparent viscosity and plastic viscosity of the drilling fluid showed a gradual increase with the increase of vinyl resin concentration at the same temperature . The yieBy studying the influence of polymers on the rheology of drilling fluid, it was found that the drilling fluid containing dimeric acid had the best low-temperature rheological performance. The plastic viscosity of the drilling fluid with 2% dimeric acid was 26.5 mpa·s at −55 °C, and the yield point was 1.25 Pa, with a 150% improvement in the yield point. However, The low-temperature rheological properties of the drilling fluid improved by the vinyl resin were the weakest. The plastic viscosity of the drilling fluid with 2% vinyl resin was 25 mpa·s at −55 °C, and the yield point was 0.5 Pa, with 0% improvement in the yield point.The study on the rheological regulation method of drilling fluid at low temperatures showed that the rheological property of drilling fluid at ultra-low temperatures was the best when the ratio of the base fluid was 7:3. When organoclay and four different polymers  were added at 2%, the yield point of drilling fluid containing organoclay was the highest, which could effectively improve the cuttings carrying and suspension performance of the drilling fluid at ultra-low temperatures.On this basis, the viscosity variation of the drilling fluids with different additives at low shear rates and the variation of shear stress with shear rate were further investigated by means of a Haake rheometer.As shown in From The influence mechanism of the different regulation methods on the rheology of drilling fluid at low temperatures was studied. The mechanism of rheology regulation was analyzed by observing the microscopic dispersion state and morphology.As can be seen from At present, the research on the rheological performance of polar drilling fluids is still basically in its infancy. In this paper, the rheological laws and adjustment methods of polar drilling fluids were studied to understand the difficult problem of low yield point and poor suspension ability of polar drilling fluids. It was shown that organoclay was the best rheological regulator for polar drilling fluids, which could effectively improve the low temperature rheological performance of drilling fluids. The four different polymers were not satisfactory for improving the rheological properties of the drilling fluids. Therefore, in future polar drilling processes, organoclay can be added to the drilling fluid to improve the low-temperature rheological properties of the drilling fluid and thus improve the drilling efficiency. This study also has a certain contribution to the development of polar drilling.The rheological performance of drilling fluid is one of the key factors governing downhole safety and affecting drilling speed during drilling. In this paper, the effects of temperature, ice debris concentration, and weighting agent on the rheological properties of drilling fluid were investigated. It was found that the lower the temperature and the higher the concentration of ice debris, the higher the viscosity of the drilling fluid. However, when the ice debris concentration was below 2%, the rheological properties of the drilling fluid did not change. The drilling fluid viscosity decreased as the weighting agent was added, and the decrease in drilling fluid viscosity reduced as the weighting agent was added. Secondly, the study of the low-temperature rheological adjustment method of drilling fluid showed that the best rheological performance of drilling fluid base fluid at ultra-low temperature was achieved when the ratio of the base fluid was 7:3. Among the organoclay and four different polymers  rheology regulators, organoclay was the best ultra-low temperature rheology regulator. The main reason for this is that organoclay is able to transform drilling fluid from Newtonian to non-Newtonian fluid and exhibit excellent shear dilution of the drilling fluid. Moreover, organoclay is more uniformly dispersed in the oil and forms a denser weak gel mesh structure. Therefore, it is more effective in improving the cuttings carrying and suspension performance of drilling fluid. However, the drilling fluid containing polymer additives is still a Newtonian fluid, which cannot form a strong mesh structure at ultra-low temperatures. Therefore, they cannot effectively improve the low-temperature rheological performance of drilling fluid. In addition, when the amount of organoclay is 2%, the improvement rate of the yield point reaches 250% at −55 °C, which can effectively improve the cuttings carrying and suspension performance of the drilling fluid at ultra-low temperatures. The results of this study have some important implications for polar oil and gas exploration and development.No. 4 aviation kerosene (purity > 98%) was purchased from Jinan Xiangtai Chemical Co., Ltd. in Jinan, China. No. 5 QY white oil (purity > 99%) was purchased from Guangdong Maoming Petrochemical Co., Ltd. in Guangdong, China. Dimeric acid (purity > 98%) and vinyl resin (purity > 98%) were purchased from Shanghai Zhipu Chemical Co., Ltd. in Shanghai, China. Polymethacrylate (purity > 85%) and ethylene propylene copolymer (purity > 85%) were purchased from Jinzhou Runzhifeng Chemical Co., Ltd. In Jinzhou, China. Baker’s commercial organoclay was purchased from Baker Petroleum Technology Development Services Co., Ltd. in Yanan, China. Monofluorodichloroethane (HCFC-141b) was purchased from Shandong Yuke Chemical Co., Ltd. Emulsifier was purchased from Hanke Petroleum Technology Co., Ltd. in Shandong, China. The emulsifier (purity > 98%) was from Chengdu Hanke Petroleum Technology Co., Ltd. in Chengdu, China.TemperatureThe rheological properties of aviation kerosene-based fluids at different temperatures are measured by using a new integrated ultra-low temperature circulating ZNN-D6 electronic viscometer . The device can be used to derive the apparent viscosity, plastic viscosity, and yield point of the drilling fluid at different temperatures, so as to judge the advantages and disadvantages of the ultra-low temperature rheological performance of the drilling fluid.A certain amount of aviation kerosene was poured into the measuring cylinder, and the temperature was controlled by the thermostat system of the above instrument to measure the size of aviation kerosene base fluid Φ600 and Φ300 at different temperatures , respectively. The apparent viscosity, plastic viscosity, and yield point were calculated by Equations.2.Ice Debris ConcentrationIce debris of specific particle size (0.1–0.3 mm) were added into aviation kerosene to investigate the effect of ice debris concentration on the rheological properties of aviation kerosene-based fluid. Deionized water was first frozen in a DW-40 ultra-low temperature thermostat , and then ice debris of specific particle size (0.1–0.3 mm) were made in an SJ-M502S ice crusher . The ice debris with different additive amounts were added to aviation kerosene separately, and the sizes of drilling fluids Φ600 and Φ300 containing different ice debris concentrations  at −55 °C were measured by a new integrated ultra-low temperature circulating ZNN-D6 electronic viscometer. the apparent viscosity, plastic viscosity, and yield point were calculated by equations.3.Aggravator Dosing3) was prepared by stirring with ZMD-550 high-speed stirrer  for 15~20 min at room temperature. The variation of apparent viscosity with the temperature  of aviation kerosene-based fluids of different densities was measured by the new integrated ultra-low temperature cycle ZNN-D6 electronic viscometer.HCFC-141b was selected as the drilling fluid aggravating agent, and different amounts of aggravating agent were added to the aviation kerosene separately. the drilling fluid with different densities  and stirred for 25~30 min with ZMD-550 high-speed stirrer , and then the effects of the base fluid ratios on the drilling fluid rheological parameters  were measured at different temperatures.2.Organoclay Rheology AdjustmentOn the basis of the base fluid (7:3), 3% of Hankook emulsifier was added and stirred for 15~20 min with ZMD-550 high-speed stirrer , followed by adding different concentrations of organoclay and continuing to stir for 15~20 min to prepare for polar drilling fluid. The changes of rheological parameters  of drilling fluid containing different concentrations of organoclay with temperature were measured by a new integrated ultra-low temperature circulation ZNN-D6 electronic viscometer.3.Polymer Regulation of Rheological Properties of Drilling FluidsOn the basis of the base fluid (7:3), polymers with different molecular structures  were added and stirred for 25~30 min with a ZMD-550 high-speed stirrer  to prepare the drilling fluids containing different polymers. The changes of the rheological parameters  with the temperature of drilling fluids containing different polymers were measured separately using a new integrated ultra-low temperature cycle ZNN-D6 electronic viscometer.The base fluid (7:3), drilling fluids containing 4% organoclay, and different polymers (4%) were frozen (−55 °C) for 16 h in a DW-40 ultra-low temperature thermostat , and then the changes in the viscosity of the drilling fluids at low shear rates were measured by a Haake MARS rheometer  at 2 °C, and the relationship between the shear stress and shear rate of the drilling fluid was measured at 2 °C. The Haake MARS rheometer can analyze whether the drilling fluid has shear dilution properties and can determine whether the drilling fluid is a Newtonian or non-Newtonian fluid.Optical Microscope AnalysisThe base fluid (7:3), drilling fluids containing 4% organoclay, and different polymers (4%) were frozen (−55 °C) for 16 h in a DW-40 ultra-low temperature thermostat , and then the dispersion and microscopic morphology of the different additives in the drilling fluids were observed through an optical microscope CX23 . Optical microscopy allows observation of the presence of weak gel mesh structures within the drilling fluid, and the measurement parameter is an image of the microscopic morphology of the drilling fluid with a size of 10 μm.


In the past decade, social media platforms have been recognized as an important tool in the dissemination of science among the research community and as an interface between scientists and the general public. Publishing companies that specialize in scientific research now pay attention to alternative metrics  and provide comprehensive guides about social media management to editors. Twitter has emerged as a leader among social media platforms in the dissemination of science. This Perspective will assert the merits of using Twitter to expand the reach of scientific conferences while providing guidance on how to disseminate conference findings in real-time, called “live-tweeting,” without compromising scientific integrity. Upon finding myself jetlagged at a conference in 2016, I attempted to stay focused on the presentations of conference speakers by publishing conference events on Twitter in real-time, a process known as “live-tweeting.” By the end of the first session, comments had started rolling in from other scientists who had been unable to attend the event, and it became apparent to me that I was providing a valuable service. Since then, I have live-tweeted 16 further conferences, stopping only if I had to present my own research. In this Perspective, I hope to impart some of the knowledge I have gained in using Twitter to provide real-time updates for scientific conferences, whether attending in-person or virtually.Among scientists, Twitter has been recognized as a positive networking tool at all career stages , 2, is a5–In medicine, Twitter has been acknowledged as a tool for online discussion at conferences, facilitating engagement between speakers and the audience and allowing those who could not attend in-person to keep abreast of conference presentations and discussions , 9. Fewe10–The basic components of an academic Twitter account are shown in Twitter also allows users to add a 160-character description underneath their profile photo and handle. This description can be used to add hashtags (“#” followed by text) that can describe the individual’s scientific interests or areas of research . The useConferences play an important role in the dissemination of novel scientific research, and Twitter can be used to expand the reach of scientific conferences. At present, scientific conference organizers do not always provide a social media manager to live-tweet events, and the task often falls to members of the conference who are more familiar with Twitter. There are a number of ways to maximize your reach when using Twitter to live-tweet a scientific conference. As shown in Most conferences will now provide an official conference hashtag, in the example case, it is “#ParasitesOnline” . Hashtaghttp://bitly.ws) or TinyURL (https://tinyurl.com/app) can be used to shorten the links.A tweet that introduces a conference speaker can be followed with more information as in https://threadreaderapp.com), which can be applied at the end of a thread as shown in In recent years, one of the most useful online tools one can use when live-tweeting conferences has been the Thread Reader App  can allow the user to log into multiple Twitter accounts at once and monitor the content released from each account. TweetDeck can prove particularly useful for learned societies or institutions with social media/communications teams made up of more than one person. Each Twitter account can have one or more administrators with the ability to grant further access to members of a communications team. Similarly, commercial social media marketing and management dashboard applications, such as “Hootsuite” (https://www.hootsuite.com), provide subscription plans to individuals, groups, or businesses who use social media platforms professionally. Hootsuite differs from TweetDeck in that it allows users to monitor all social media applications at once and gives users the ability to prepare social media releases in advance of specific campaigns or events. Using these applications, conference seminars and events can be posted from multiple Twitter or mixed social media platforms at once.There are additional tools that may become useful if an individual user gains access to multiple Twitter accounts or multiple social media platforms, for example, an individual employed to manage social media platforms for a company or a publishing house. When tasked with managing more than one Twitter account, the free social media dashboard application “TweetDeck”  as a measure of scientific research impact, services to science communication, such as live-tweeting scientific conferences, may be recognized as a valuable contribution to education and the democratization of scientific information, perhaps being incorporated into portfolios for academic promotion and tenure –25. Unti–https://zoom.us) and Slack (https://slack.com) have gained favor within the research community. In the future, conference notifications and science communication may move to new apps, such as Reddit (https://www.reddit.com), Discord (https://discord.com), Mastodon (https://joinmastodon.org), or others, and science communicators will need to move with them.At present, Twitter remains the primary social media platform for real-time scientific conference updates. Even so, as the landscape of communications technology and software applications changes over time, so too will the communication of science and the avenues by which scientists network and engage with the general public. As the COVID-19 pandemic made conferences and work more virtual in nature, applications such as Zoom (


State legislators make policy decisions that influence children’s exposure to adverse childhood experiences (ACEs), such as child maltreatment, and their effects on behavioral health. Effective dissemination of scientific research can increase the likelihood that legislators’ decisions are aligned with evidence to prevent ACEs and their consequences, and effective dissemination requires legislators to engage with dissemination materials. Informed by the elaboration likelihood model of persuasive communication and Brownson’s Model of Dissemination Research, we tested the hypothesis that inclusion of economic evidence and local data would increase legislator engagement with dissemination materials about evidence-supported policies related to ACEs and behavioral health.A three-arm randomized dissemination trial was conducted. A university researcher e-mailed dissemination materials which contained evidence about ACEs and behavioral health problems to state legislators . The e-mail subject lines, text, and policy brief content were manipulated across the study arms. The intervention condition received state-tailored data about rates of ACEs and state-tailored economic evidence about the costs of ACEs for public systems, the enhanced control condition received state-tailored data and not economic evidence, and the control condition received national data and not economic evidence. Outcomes were rates of e-mail views, policy brief link clicks, requests for researcher consultation, and mentions of child maltreatment terms in legislators’ social media posts.p < .0001). Similar results were observed for the second e-mail. These differences remained significant after adjustment for demographic differences across study conditions in individual-level models, but not multilevel models. There was a significant interaction between the experimental condition and political party (p < .0001) in which the intervention increased e-mail view rates among Democrats but not Republicans. The intervention had no effect on policy brief link clicks or requests for consultation and a mixed effect on social media posts.For the first e-mail, the e-mail view rate was 42.6% higher in the intervention than in the enhanced control condition (22.8% vs. 14.8%) and 20.8% higher than in the control condition (22.8% vs. 18.5%) (both Inclusion of state-tailored economic evidence in dissemination materials can increase engagement with research evidence among Democrat, but not Republican, legislators. Dissemination strategies tailored for legislators’ political party affiliation may be needed.The online version contains supplementary material available at 10.1186/s13012-022-01214-7. Contributions to the literatureBoth dissemination research and policy-focused research are underdeveloped areas of implementation science, especially in the USA.Political identity has received little attention as a variable in implementation science.The current study illustrates how a cluster randomized design can be used to make causal inferences about the effects of including different types of evidence in dissemination materials for elected policymakers and the moderating effects of political identity.Inclusion of economic evidence in dissemination materials increases engagement with dissemination materials among Democrats, but not Republican, elected policymakers.Results support the inclusion of economic evidence in dissemination materials for elected policymakers, but also signal the potential value of tailoring dissemination materials for policymakers based on their political party affiliation.Implementation Science, concluded that very little quantitative research has evaluated the effects of policymaker-targeted dissemination strategies [Dissemination research—defined by the US National Institutes of Health as “the scientific study of targeted distribution of information and intervention materials to a specific public health or clinical practice audience” —is underrategies . As a corategies , 8. Whilrategies , 10, theBuilding on descriptive research with state legislators about mental health and substance use  issues –18, the The current study focuses on disseminating evidence about adverse childhood experiences (ACEs) as risk factors for behavioral health problems and evidence-supported policy strategies to address ACEs. ACEs include incidents of child maltreatment—such as physical and sexual abuse and neglect—as well as other adverse experiences before age 18, such as witnessing domestic and community violence –22. ACEsState legislators (there are 7383 in the USA) are an important audience to target with the dissemination of evidence about ACEs because they make policy decisions that can reduce exposure to ACEs and mitigate their behavioral health consequences –28. ReviDespite the potential of state legislators to address ACEs, the legislative response to ACEs and legislators’ knowledge about ACEs are suboptimal. A recent review found that only 20.5% of bills introduced in state legislatures that mentioned ACEs also identified evidence-based or evidence-supported interventions related to ACEs . This anPrior research conducted with state legislators provides additional guidance about how to develop dissemination materials about ACEs for state legislators. The aforementioned 2017 survey of legislators found that the local relevance of data and the inclusion of economic evidence were perceived as extremely important attributes of behavioral health dissemination materials, especially among Republicans , 13, 15.types of evidence to include. This knowledge gap is important because only a finite amount of evidence can be included in concise dissemination materials, and research demonstrates that shorter presentations of evidence are preferred by legislators [While prior work sheds light on how to format dissemination materials, it sheds little light on what islators , 11. Verislators . This knislators , 55, theislators , 57.and state-tailored data about rates of ACEs in dissemination materials (intervention) increases legislator engagement with dissemination materials compared with inclusion of national data about rates of ACEs and no economic evidence (control)Inclusion of state-tailored economic evidence about ACEs and state-tailored data about rates of ACEs in dissemination materials (intervention) increases engagement with dissemination materials compared with inclusion of state-tailored data about rates of ACEs and no economic evidence (enhanced control)Inclusion of state-tailored economic evidence about ACEs Inclusion of state-tailored data about rates of ACEs and no economic evidence (enhanced control) increases engagement with dissemination materials compared with inclusion of national data about rates of ACEs and no economic evidence (control)The primary aims of the study were to test the pre-registered hypotheses that:The secondary, exploratory aims were to determine whether the effects of dissemination materials were moderated by legislators’ political party affiliation and to assess the extent to which engagement with dissemination materials is independently associated with political party affiliation.We focus on measures of engagement with dissemination materials as our outcome for three reasons. First, engagement is considered an important dissemination outcome , 58. Mearelevant by audiences influences the extent to which audiences engage with and cognitively process the message. Based on prior research with state legislators [The elaboration likelihood model (ELM) of persuasive communication provides the theoretical basis for our hypotheses –64. ELM islators , 13, 15,islators . Given eislators .source is a university researcher, the message is evidence about ACEs and behavioral health , the channel used to deliver the message is e-mail, and the audience is US state legislators and their staff.The overarching structure of our study is also informed by Brownson and colleagues’ Model of Dissemination Research , which whttps://osf.io/cgh64; Supplemental file We conducted a pre-registered, clustered randomized dissemination field experiment . Randomization was at the state level to avoid contamination, wherein a legislator assigned to one condition would share dissemination materials with a legislator assigned to a different condition in the same state. Randomization was stratified to approximate balance in the number of legislators in each condition and the percentage of legislators in each condition that were Republican. We stratified on these two variables because the number of legislators in each state varies dramatically  and prior research has shown that legislators’ opinions about ACEs vary significantly by political party .To carry out stratified randomization, we classified each state according to whether the size of its legislature was less than the national median of 139 and whether the percentage of the legislature that was Republican was less than the national mean of 53.3%. This resulted in four strata of states defined by the cross-classification of legislature size and percentage of Republican legislators. We then randomized the states within each stratum for a balanced design, assigning all legislators within each state to the same study condition .intervention condition were sent state-tailored data about rates of ACEs and state-tailored economic evidence about the costs of ACEs for public systems’ legislators in the enhanced control condition were sent state-tailored data about rates of ACEs and no economic evidence, and legislators in the control condition were sent national data about rates of ACEs and no economic evidence. Three elements of dissemination materials were manipulated in each condition: e-mail subject line, e-mail body test, and policy brief content.Legislators in the The syntaxes of the e-mail subject lines were identical with the exception of elements that were modified to emphasize core aspects of each study condition. We used the language “Child Maltreatment,” as opposed to “Adverse Childhood Experiences,” in e-mail subject lines and language of “child maltreatment and adverse childhood experiences” in the e-mail body text because we assumed that more legislators would be familiar with the term “child maltreatment” than ACEs . The subThe body text of the e-mails was modified similarly to summarize evidence contained in the policy brief  were removed from the second e-mail.Two e-mails were sent from the project PI’s university e-mail account using Qualtrics over the course of 3 weeks . Legislators for whom e-mails bounced back as undeliverable in the first e-mail  for each of the two e-mails. Mentions of topics related to ACEs in legislators’ Facebook and Twitter posts and newsletters to constituents were assessed using Quorum, a database that compiles this information in real time and has been previously used to characterize legislators’ public communication about health issues –83. We sInformation about the demographic characteristics of legislators was obtained from the KnowWho database and served as covariates. Political party affiliation was operationalized as Republican or non-Republican , gen = 492 in the first e-mail analysis, n = 356 in the second e-mail analysis) were excluded from the analysis. Data from the first and second dissemination e-mails were analyzed separately. Chi-square tests were used in randomization checks to assess differences in demographic characteristics of legislators across the three study conditions in each dissemination e-mail.Analysis was conducted at the individual legislator level because the e-mail dissemination intervention and outcome assessment were at this level. Legislators for whom e-mails were undeliverable . We ran single as well as multilevel  random-intercept models to account for correlated outcomes between legislators in the same state  [We use results from both unadjusted and adjusted analyses to determine the effects of dissemination materials because there is a lack of consensus about whether it is appropriate to adjust for demographic differences across conditions in randomized trials , 85. We stering) . The intstering) . Our priThe first dissemination e-mail was successfully delivered to 6509 legislators and the second e-mail was delivered to 6153 legislators. CONSORT diagrams are included as Supplemental file p < .0001, Table p<.0001).E-mail views were registered for 1220 (18.7%) legislators in the first dissemination e-mail and 1089 (17.7%) in the second e-mail. In the first e-mail, the view rate was 42.6% higher in the intervention than enhanced control condition (22.8% vs. 14.9%) and 20.8% higher in the intervention than control condition (22.8% vs. 18.5%) . The point estimates of the intervention effect were nearly identical in multilevel models that accounted for state clustering, but confidence intervals were wider and results were not statistically significant. The enhanced control treatment did not have a statistically significant effect on e-mail views compared to the control in unadjusted or adjusted analyses.The effect of the intervention treatment on e-mail views generally remained significant after adjustment for demographics in individual-level logistic regression models Table . For exap=. 002 and enhanced control vs. control: p= .0008). Among Democrats in the first e-mail, the e-mail view rate was 38.2% higher in the intervention than control condition , while the view rate was nearly identical among Republicans across these two conditions (17.4% vs. 17.8%)  lower in the enhanced control than control group among Republicans in the first e-mail (11.3% vs. 17.8%) as well as the second e-mail (13.2% vs. 15.1%). This was not observed among Democrats.The effects of the intervention treatment on e-mail views were moderated by political party affiliation. The political party*study condition interaction term was statistically significant in the individual-level model (intervention vs. control: Policy brief link clicks were registered for 208 (3.2%) legislators in the first dissemination e-mail and 142 (2.3%) in the second e-mail. There were no significant differences in link click rates across the study conditions in unadjusted or adjusted analyses. There was no significant interaction between political party affiliation and study condition for link clicks.Following the first dissemination e-mail, 16 (0.3%) legislators requested consultation and 22 (0.4%) requested consultation following the second e-mail. There were no significant differences in the frequency of requests for consultation across the study conditions in unadjusted or adjusted analyses. There was also no significant interaction between political party affiliation and study condition for the consultation outcome.p = .04). However, the intervention treatment significantly reduced the odds of a legislator explicitly mentioning ACEs compared to the enhanced control  and control  conditions.In the 2-month period following the date when the first dissemination e-mail was sent, 238 (3.9%) of legislators posted or sent ≥1 messages that mentioned any terms related to child maltreatment broadly or ACEs explicitly. The intervention condition did not impact the odds of a legislator mentioning the terms when mentions of the two terms were analyzed together Table . Supplemp < .0001), two times higher odds of clicking the policy brief link , and over eight times higher odds of requesting consultation  than did Republicans. Similar results were observed in the second e-mail.After adjustment for study experimental condition, gender, and race/ethnicity, and state-level clustering, Democrats remained significantly more likely than Republicans to view the dissemination e-mails, view the policy briefs, and request consultation. For example, in the multilevel model for the first dissemination e-mail, Democrats had 49% higher odds of viewing the e-mail , assessment of outcomes via unobtrusive measures for the entire study population as opposed to surveys with a potentially non-representative sample of the population , assessment of multiple measures of engagement with dissemination materials ranging from the very proximal  to more distal , assessment outcomes at the individual level , and the multilevel analysis approach.A limitation of our study relates to the imprecise measurement of e-mail views and policy brief link clicks. Although these outcomes were assessed using marketing industry best practices that are standard in dissemination research, they are inherently imprecise because some e-mail servers and account settings block the automatic pixel downloads and link click logins used to register engagement outcomes. However, while this error may have affected study power, it should theoretically have been nondifferential with respect to study condition because of the study’s randomized design . Our stuIt should be emphasized that the e-mails were sent from a university researcher. While both Republican and Democrat legislators have identified university researchers as a credible source of research evidence in prior work , other smore effective at prompting engagement with dissemination materials among Republican legislators. After adjustment for covariates, Republican legislators engaged with evidence disseminated from a university researcher at significantly lower rates than did Democrats. Taken together, the study findings support the inclusion of economic evidence in legislator-targeted dissemination materials but also highlight a need for future research that tests the effects of tailoring dissemination materials for legislators with different political party affiliations.Inclusion of state-tailored economic evidence in dissemination materials can increase engagement with research evidence among Democrat, but not Republican, legislators. Inclusion of state, as opposed to national, incidence/prevalence data does not have this effect, and national data might actually be Additional file 1. CONSORT and TIDieR checklists.Additional file 2. CONSORT Diagram.Additional file 3. E-mail text.Additional file 4. Example Policy Briefs.Additional file 5. Unadjusted and Adjusted Associations between Study Conditions, Demographics, and Mentions of Terms Related to Dissemination Materials in U.S. State Legislators’ Social Media Posts and Newsletters to Constituents, 2021.