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This review discusses the application scenarios of the machine learning-supported performance prediction and the optimization efficiency of tunnel boring machines (TBMs). The rock mass quality ratings, which are based on the Chinese code for geological survey, were used to provide “labels” suitable for supervised learning. As a result, the generation of machine prediction for rock mass grades reasonably agreed with the ground truth documented in geological maps. In contrast, the main operational parameters, i.e., thrust and torque, can be reasonably predicted based on historical data. Consequently, 18 collapse sections of the Yinsong project have been successfully predicted by several researchers. Preliminary studies on the selection of the optimal penetration rate and cost were conducted. This review also presents a summary of the main achievements in response to the initiatives of the Lotus Pool Contest in China. For the first time, large and well-documented TBM performance data has been shared for joint scientific research. Moreover, the review discusses the technical problems that require further study and the perspectives in the future development of intelligent TBM construction based on big data and machine learning.

Abstract

An electrochemical method was developed to analyze the alkali metal ion transfer across the water/1,2-dichloroethane interfaces facilitated by dibenzo-18-crown-6 ether (DB18C6) by observing the collisions of single emulsion droplets on an ultramicroelectrode (UME). The water-in-oil emulsion droplets were stabilized by an ionic liquid of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides, in which a highly hydrophilic redox probe of potassium ferrocyanide/ferricyanide (K3Fe(CN)6/ K4Fe(CN)6) was used. When the droplets collided with the UME that was biased at a potential to drive the oxidation reaction of [Fe(CN)6]4−(0.05 mol/L), the current spikes could be observed only with the addition of DB18C6. It was suggested that the DB18C6 as K+ionophore facilitated the K+transfer from the water to the oil to maintain charge balance during the electrolysis. As more K+ionophores were added, the integrated charge of the current spikes showed a rising trend in general because of the ionophore to lower the Gibbs energy of ion transfer. Further collision experiments were conducted to investigate the transfer of Na+and K+cations facilitated by the DB18C6. The order in which the “voltammetric” oxidation waves appeared indicated that the ionophore of DB18C6 was more efficient in carrying K+across the water/1,2-Dichloroethane interface. Thereby, the collision electrochemistry is a convenient and effective mean to study the ion selectivity of ionophore.

Low-dose computed tomography lung cancer screening aims to detect early-stage lung cancers in order to decrease the incidence of advanced-stage lung cancers and to reduce lung cancer mortality. We analyzed the time trends of lung cancer stage distribution and mortality rates after the gradual implementation of the low-dose computed tomography lung cancer screening in a hospital-based cohort. Using the hospital-based cancer registry data on lung cancer number and death from 2007 to 2014, we aim to evaluate the trends in stage distribution and mortality rate after the gradual implementation of low-dose computed tomography lung cancer screening program over recent years. From 2007 to 2014, overall 2542 cases of lung cancers were diagnosed according to hospital-based cancer registry. For the 1-year mortality rate, the mortality rate decreased gradually from 48.16 to 37.04% between 2007 and 2014. For the 5-year mortality rate, the mortality rate decreased gradually from 88.49 to 69.44% between 2007 and 2014. There was a gradual decrease in stage IV lung cancer with the corresponding sharp increase in stage I early lung cancer after following the implementation of the large volume of the low-dose computed tomography examination between the years 2011 and 2014. In conclusion, these results suggest that the gradual implementation of low-dose computed tomography lung screening program could lead to a remarkable decrease in lung cancer mortality and a remarkable stage shift in the trend over time in this hospital-based cohort.

Chemically modified carbonaceous materials have attained utmost attention in the fields of renew-able energy storage and conversion, due to the controllable physicochemical properties, tailorable micro-/nanostructures, and respectable stability. Herein, P-doped mesoporous carbons were syn-thesized by using F127 as the soft template, organophosphonic acid as the P source and phenolic resin as the carbon source. Small amounts of iron species were introduced to act as a graphitization catalyst. The synthesized carbons exhibit the well-defined wormhole-like pore structure featuring high specific surface area and homogenously doped P heteroatoms. Notably, introducing iron spe-cies during the synthesis process can optimize the textural properties and the degree of graphitiza-tion of carbon materials. The doping amount of P has an important effect on the porous structure and the defect degree, which correspondingly influence the active sites and the oxygen reduction reaction (ORR) activity. The resultant material presents superior catalytic activity for the ORR, together with remarkably enhanced durability and methanol tolerance in comparison with the commercial Platinum catalyst, demonstrating the possibility for its use in electrode materials and electronic nanodevices for metal-air batteries and fuel cells.

Pseudocapacitance is generally associated with either surface redox reactions or ion intercalation processes without a phase transition. Typically, these two mechanisms have been independently studied, and most works have focused on optimizing one or the other in different material systems. Here we have developed a strategy based on solubility contrast, in which the contribution from the two capacitive mechanisms is simultaneously optimized. Taking layered birnessite MnO2as a model, controllable nanostructures and oxygen vacancies are achieved through a simple coprecipitation process. Simultaneously controlling crystallite size and defect concentration is shown to enhance the charging-discharging kinetics together with both redox and intercalation capacitances. This synergistic effect results from enhanced ionic diffusion, electronic conductivity, and large surface-to-volume ratio. In addition, considerable cycling durability is achieved, resulting from improved framework strength by defect creation and the absence of proton (de)intercalation during discharge/charge. This work underscores the importance of synergistically regulating nanostructure and defects in redox-active materials to improve pseudocapacitive charge storage.

Developing efficient electrocatalysts consisting of earth-abundant elements for oxygen evolution reaction (OER) is crucial for energy devices and technologies. Herein, we report self-supported highly porous nitrogen-doped graphene foam synthesized through the electrochemical expansion of carbon-fiber paper and subsequent nitrogen plasma treatment. A thorough characterization, such as electron microscopy and synchrotron-based near-edge X-ray absorption fine structure, indicates the well-developed porous structures featuring homogeneously doped nitrogen heteroatoms. These merits ensure enriched active sites, an enlarged active surface area, and improved mass/electron transport within the continuous graphene framework, thus leading to an outstanding capability toward electrocatalyzing OER in alkaline media, even competitive with the state-of-the-art noble-/transition-metal and nonmetal electrocatalysts reported to date, from the perspectives of the sharp onset potential, a small Tafel slope, and remarkable durability. Furthermore, a rechargeable Zn–air battery with this self-supported electrocatalyst directly used as the air cathode renders a low charge/discharge overpotential and considerable life span. The finding herein suggests that a rational methodology to synthesize graphene-based materials can significantly enhance the oxygen electrocatalysis, thereby promoting the overall performance of the energy-related system.

This review summarizes the research outcomes and findings documented in 45 journal papers using a shared tunnel boring machine (TBM) dataset for performance prediction and boring efficiency optimization using machine learning methods. The big dataset was collected during the Yinsong water diversion project construction in China, covering the tunnel excavation of a 20 km-section with 199 items of monitoring metrics taken with an interval of one second. The research papers were the result of a call for contributions during a TBM machine learning contest in 2019 and covered a variety of topics related to the intelligent construction of TBM. This review comprises two parts. Part I is concerned with the data processing, feature extraction, and machine learning methods applied by the contributors. The review finds that the data-driven and knowledge-driven approaches in extracting important features applied by various authors are diversified, requiring further studies to achieve commonly accepted criteria. The techniques for cleaning and amending the raw data adopted by the contributors were summarized, indicating some highlights such as the importance of sufficiently high frequency of data acquisition (higher than 1 second), classification and standardization for the data preprocessing process, and the appropriate selections of features in a boring cycle. The review finds that both supervised and unsupervised machine learning methods have been utilized by various researchers. The ensemble and deep learning methods have found wide applications. Part I highlights the important features of the individual methods applied by the contributors, including the structures of the algorithm, selection of hyperparameters, and model validation approaches.

In spite of being technologically feasible, electrochemical water reduction to facilitate hydrogen production is confronted with issues mainly due to the lack of affordable and efficient catalysts for the water reduction half reaction. Reported herein is the fabrication of metal phosphides nanocrystals uniformly loaded on highly porous heteroatom-modified carbons through one-step carbonization–phosphization methodology. Remarkably, the well-structured porosity and the increased electrochemically accessible active sites ensure the high catalytic efficiency for electrochemical hydrogen evolution in acidic medium in terms of small onset potentials (33 mV) and large cathodic current density (0.481 mA cm–2), even comparable to the state-of-the-art Pt/C benchmark. The easily prepared composite catalysts of structural and textural peculiarities may serve as promising non-noble metal catalysts for realistic hydrogen evolution.

Graphitic carbon nitride (g-C3N4) has been deemed a promising heterogeneous metal-free catalyst for a wide range of applications, such as solar energy utilization toward water splitting, and its photocatalytic performance is reasonably adjustable through tailoring its texture and its electronic and optical properties. Here phosphorus-doped graphitic carbon nitride nanostructured flowers of in-plane mesopores are synthesized by a co-condensation method in the absence of any templates. The interesting structures, together with the phosphorus doping, can promote light trapping, mass transfer, and charge separation, enabling it to perform as a more impressive catalyst than its pristine carbon nitride counterpart for catalytic hydrogen evolution under visible light irradiation. The catalyst has low cost, is environmentally friendly, and represents a potential candidate in photoelectrochemistry.

Catalysis is crucial for sustainable process management. The discovery of mesoporous metal phosphonate hybrid materials has opened great opportunities for new applications in catalysis, thanks to their homogeneous composition, combined merits of inorganic units and organic groups, and considerable porosity. In this review, we present the fundamentals of designing and optimizing hybrid mesostructures and the recent progress in the fields of metal phosphonate-based catalytic reactions. The catalytic reactions are divided into three categories based on the following elements, i.e., metal sites, organophosphonate moieties, and potential precursors of active metal phosphates. Each section highlights recent advances and the corresponding reactions are discussed in detail. Direct functionalization of the mesopore surfaces of the hybrids, such as sulfonation and supporting, features an elegant way to bridge the gap between heterogeneous and homogeneous catalysis. Moreover, remarks on the challenges and perspectives are presented for further exploration of mesoporous metal phosphonate hybrid heterogeneous catalysts.

Porous phosphonate-based organic–inorganic hybrid materials have been shown to have novel and amazing physicochemical properties due to the integration of superiorities from both inorganic components and organic moieties. Herein, mesoporous cerium phosphonate nanostructured hybrid spheres are prepared with the assistance of cationic surfactant cetyltrimethylammonium bromide while using ethylene diamine tetra(methylene phosphonic acid) as the coupling molecule. The resulting hybrid is constructed from the cerium phosphonate nanoparticles, accompanied by high specific surface area of 455 m2g–1. The uniform incorporation of rare-earth element cerium and organophosphonic functionalities endows mesoporous cerium phosphonate with excellent fluorescence properties for the development of an optical sensor for selective Hg2+detection on the basis of the fluorescence-quenching mechanism. The signal response of mesoporous cerium phosphonate against the Hg2+concentration is linear over the range from 0.05 to 1.5 μmol L–1, giving a limit of detection of 16 nmol L–1(at a signal-to-noise ratio of 3). Most of the common physiologically relevant cations and anions did not interfere with the detection of Hg2+. This label-free system provides a promising platform for further use in bioimaging and biomedical fields.

The nanocomposite photocatalysts of carbon-doped zinc oxide (ZnO) hybridized with graphitic carbon nitride (g-C3N4) were prepared through simple one-step calcination of evaporation-dried mixture of dicyandiamide and zinc nitrate. Compared with pure ZnO and g-C3N4, the absorption of the prepared g-C3N4/ZnO nanocomposites shifted toward lower energy region, and the broader and stronger absorbance in the visible light region was observed, which was related to the content of g-C3N4in the nanocomposites. The photocatalytic activities of the resultant g-C3N4/ZnO nanocomposites for the degradation of methylene blue (MB) dye under visible light irradiation were enhanced remarkably and much higher than that of g-C3N4. The optimal content of g-C3N4in the prepared nanocomposites was found at a weight percent of 50.7%, which corresponded to the homogeneous hybridization between ZnO and g-C3N4. The improved photocatalytic performance of the g-C3N4/ZnO nanocomposites was ascribed to the elevation of the separation efficiency of photoinduced electron–hole pairs, resulting from the heterojunction established between the interfaces of g-C3N4and ZnO.

Orbital reconstruction is a difficult procedure, success of which is dependent on the surgeon’s experience. The lack of objective methods requires a fair amount of estimation is its execution. This study evaluates the efficacy of Kolibri (BrainLab, Munich, Germany), an intraoperative navigation device, in improving outcomes.

Mesoporous Al2O3 was synthesized from aluminum nitrate using different surfactants as structure-directing agents. The adsorption capability of prepared Al2O3 was studied in methyl orange solution. The Al2O3 prepared by Tween80-mediated has the best adsorption capability. The surfactant dosage influences the pore structure and adsorption capability of Al2O3, the best Tween80 dosage is 0.3g. Pore size distribution shows that the prepared Al2O3 has mesoporous structure, the pore diameter mainly centers at 1-4nm. For the inner diffusional resistance of the pore canal to achieve adsorption balance, suitable adsorption time is 80 minutes.

Nanoparticle–hydrogel systems have recently emerged as a class of interesting hybrid materials with immense potential for several biomedical applications. Remarkably, the incorporation of nanoparticles into a hydrogel may yield synergistic benefits lacking in a singular system. However, most synthetic strategies require laborious steps to achieve the system, severely restricting the process of translational research. Herein, a facile strategy to access a two-in-one system comprising two distinct polyurethane (PU)-based micellar systems is demonstrated and applied as a novel sustained gene delivery platform, where the two PUs are synthesized similarly but with slightly different compositions. One PU forms cationic micelles that complex with plasmid DNA (pDNA), which are loaded into a thermogel formed by another PU micellar system for the prolonged release of pDNA micelleplexes. Specifically, a thermogelling multiblock PU copolymer (denoted as EPH) was synthesized via the step-growth polymerization of poly(ethylene glycol), poly(propylene glycol), and poly(3-hydroxybutyrate). By further introducing a cationic extender, 3-(dimethylamino)-1,2-propanediol, into the reaction feed, a series of cationic PUs (denoted as EPHD) with varying compositions were obtained. The EPHDs formed positively charged micelles in aqueous solutions, efficiently condensed pDNA into nano-sized micelleplexes (<200 nm) at optimized w/w ratios, and mediated transient green fluorescence protein expression in HEK293T cells at 48 h post-transfection. On the other hand, aqueous EPH solution (4 wt %) was injectable at 4 °C and rapidly gelled upon heating to 37 °C to form a stable hydrogel depot. EPHD/pDNA micelleplexes were easily loaded into EPH by mixing the solutions at 4 °C, before heating to 37 °C, leading to the resultant hydrogel system. The in vitro release study revealed that while free pDNA loaded in the thermogel was completely released in 2 weeks, the release of EPHD/pDNA micelleplexes was prolonged to at least 28 days, suggesting substantial micelleplex–hydrogel interactions. Intact, bioactive, and noncytotoxic EPHD/pDNA micelleplexes in the release media were proved by gel retardation, in vitro gene transfection, and CCK-8 cytotoxicity assay results, respectively. Collectively, this work presents a simple approach to achieving and optimizing a novel two-in-one nanoparticle–hydrogel system for the prolonged delivery of pDNA and may be promising for long-term gene delivery applications.

This paper addresses the significance of preprocessing big data collected during a tunnel boring machine (TBM) excavation before it is used for machine learning on various TBM performance predictions. The research work is based on two water diversion tunneling projects that cover 29.52 km and 17 051 boring cycles. It has been found that the penetration rate calculated from the raw measured penetration distances exhibits more random behavior owing to their percussive and vibratory behavior of the cutterhead. A moving average method to process the negative instantaneous velocities and a noise reduction filter to deal with signals with abnormal frequencies have been recommended. An index called the drilling efficiency index is introduced to assess the relationships between the mechanical parameters in a boring cycle, whose linear regression coefficient R2is taken for a preliminary investigation of possible problems requiring preprocessing. The research work defines the irrelevant data whose errors are caused by human or mechanical mistakes, and therefore should be cleaned or amended. These irrelevant data can be divided into five categories: (1)premature cycles, (2)sensor defects, (3)mechanical defects, (4)human interruption, and (5)missing files. A program TBM-Processing has been coded for the recognition and classification of these categories. PDF books generated by the program have been uploaded at GitHub to encourage discussions, collaboration, and upgrading of the data processing work with our peers.

Easy and hard magnetization curves of YCo4B compound have been measured in the temperature range from 1.5 to 300 K. It was found that the uniaxial magnetic anisotropy field decreases with decreasing temperature, and the magnetic anisotropy changes from the easy c-axis to the easy cone at approximately 150 K. The easy and hard magnetization curves did not cross up to 6 T. High field susceptibility of the compound for magnetic field parallel to the alignment direction seems different from that for a field perpendicular to the alignment direction. A jump was observed along the easy magnetization curve at 1.5 and 77 K. The critical field of the jump is about 1.5 T at 1.5 K and 1.2 T at 77 K. The jump was shown to be reversible at 1.5 K by down hill measurement.

Loaches,Misgurnus anguillicaudatus (Cantor), a common fish in Taiwan, were treated with DDT, dieldrin, and monocrotophos by continuous exposure in aqueous solutions (or suspensions) and by injection. DDT and dieldrin were 150 and 220 times more toxic, respectively, than monocrotophos, to the fish exposed in aqueous solutions (24-hr LC50), but only 1/9 and 1/4 as toxic as monocrotophos by injection (24-hr LD50). Results of GLC analyses indicate that, at the end of 24-hr exposure, 96.5% of DDT, 92.7% of dieldrin, and 14.3% of monocrotophos were absorbed by loaches from aqueous solutions. The initial rates of absorption for DDT and dieldrin were about 10 to 20 times faster than that for monocrotophos. The large differences in relative toxicity may be due to partition distribution which in turn caused differences in absorption, as DDT and dieldrin are lipophilic and monocrotophos is hydrophilic. Statistical analysis of the relationship between fish toxicities and partition coefficients supports the present finding. The coefficient of correlation is 0.70 between partition coefficients (benzene/water) and toxicities to fish (rainbow trout) of 12 organophosphorus insecticides, 0.74 between coefficients and corrected fish toxicities, and 0.96 between partition coefficients and corrected fish toxicities for organophosphates only. Results of analyses are significant at <1% probability level. Similar correlation was also obtained between partition coefficients for hexane/water and toxicities of 8 organophosphorus and 5 organochlorine insecticides to rainbow trout.

Unraveling the atomistic structures of electric double layers (EDL) at electrified interfaces is of paramount importance for understanding the mechanisms of electrocatalytic reactions and rationally designing electrode materials with better performance. Despite numerous efforts dedicated in the past, a molecular level understanding of the EDL is still lacking. Combining the state-of-the-art ab initio molecular dynamics (AIMD) and recently developed computational standard hydrogen electrode (cSHE) method, it is possible to realistically simulate the EDL under well-defined electrochemical conditions. In this work, we report extensive AIMD calculation of the electrified Pt(111)-Had/water interfaces at the saturation coverage of adsorbed hydrogen (Had) corresponding to the typical hydrogen evolution reaction conditions. We calculate the electrode potentials of a series of EDL models with various surface charge densities using the cSHE method and further obtain the Helmholtz capacitance that agrees with experiment. Furthermore, the AIMD simulations allow for detailed structural analyses of the electrified interfaces, such as the distribution of adsorbate Hadand the structures of interface water and counterions, which can in turn explain the computed dielectric property of interface water. Our calculation provides valuable molecular insight into the electrified interfaces and a solid basis for understanding a variety of electrochemical processes occurring inside the EDL.

A critical limitation to conventional electrochemical double-layer capacitors is their low energy densities. This has triggered significant interest in developing new pseudocapacitive materials, which utilize faradaic mechanisms to increase their energy densities. In this work, graphitic carbon nitride (g-C3N4) and Ti3C2TxMXene are hybridized to form a unique two-dimensional (2D) heterostructure, which delivers remarkable pseudocapacitive characteristics and robust stability towards lithium storage. Interestingly, the improved kinetics is reflected by insignificant influence of (dis)charge rates on the pseudocapacitance even when testing at a 120C rate, and small peak potential offsets at high scan rates, revealing that there are no significant diffusion limitations in the heterostructure. This unexpected fast kinetics is related to the intrinsic chemical and electronic coupling effects between g-C3N4and MXene, which can synergistically improve both electron transfer and lithium diffusion kinetics compared to MXene itself.

The dynamics of toxic effects of monocrotophos, Isolan® (1-isopropyl-3-methyl-5-pyrazolyl dimethylcarbamate), and sodium pentobarbital on the water conservation and weight loss of female house flies,Musca domeslica L., were studied during their intoxication and recovery. Generally, the rate of weight loss was high soon after injection or topical application. In some cases, weight loss was detected before any visible symptoms of excitation. Apparently, the mechanism of water conservation could be impaired by toxicants long before visible intoxication. For flies treated with Isolan or sodium pentobarbital, the rate of weight loss rapidly decreased as the flies recovered from the toxic effects, Finally, the rates of weight loss diminished to about the same as untreated checks. It appears that the mechanism of water conservation was disrupted by the toxic effect but was restored gradually as soon as the flies recovered from intoxication. However, the rate of weight loss of monocrotophos-treated flies remained at high levels. Within a 15-minnte period after death, water content of starved flies was 65.0±0.6% SE, whereas that of living flies was 67.2±0.54%. Difference in water content between living and dead flies was about 2%.

An infusion method is described for administering insecticides into house flies or other insects at constant rates. The calibration of infusion equipment and reproducibility of this method are presented in comparison with topical application and injection results. Because of leakage under infusion pressure, the observed volume of infusion should be calibrated with insects on the needle for each solvent, each infusion time, each rate of infusion, and each insert species. In spite of slow and tedious operation, this technique, together with topical application and injection data, could reveal additional information on the penetration, storage, and detoxication of insecticides in insects. Comparison of the relative activity ratio between topical application and injection and between infusion and injection suggests that, similar to DDT, the site of action of dieldrin on house flies, Musca domestica L., may be the peripheral nervous system rather than the central nervous system.

To analyze the joint action of two (or more) insecticides, the actual toxicity indexes of the components and their mixture are determined by dosage-mortality curves. The theoretical toxicity of the same mixture is equal to the sum of toxicity indexes calculated from the percentage of each component times its respective toxicity index. Therefore, the joint toxicity or Co-toxicity coefficient of a mixture A coefficient of a mixture near 100 indicates probability of similar action; independent action usually should give a coefficient less than 100, while a coefficient significantly above 100 strongly indicates synergism. Toxicity significantly less than that of the strongest toxicant alone shows antagonism. Thirty-nine mixtures each containing two to four insecticides were tested against the house fly (Musca domestica L.) and their results were calculated by this method. Generally, chemically related compounds gave similar action, while unrelated compounds gave independent action. 3-(Dimethoxyphosphinyloxy)-N,N-dimethyl-crotonamide (SD 3562)and sesamex showed high synergistic action. However, a mixture of methyl parathion and sesamex indicated significant antagonism.

When dieldrin is infused into house flies, Musca domestica L., its toxicity is much less than when it is injected into them. Similar results were obtained for DDT hilt not for SD 11319 (3-hydroxy-cis-crotonamide dimethyl phosphate). It was suspected that during infusion a good part of the dieldrin and DDT was adsorbed onto proteins or partitioned into lipids and thus was not available for penetration to the site of action. However, because of the hydrophilic property) of SD 11319, its activity was about the same by either injection or infusion. Analyses of C14dieldrin in house flies following injection and infusion indicate the effects of adsorption and partition on the distribution of dieldrin. No large differences could be found. The rate of penetration and amount of C14dieldrin in the hemolymph and in the central nervous system, following injection or infusion, do not provide the same magnitude of difference as for the toxicity results.

When tested against Musca domestica L., by a spray method, sesamex symergized the toxicity of ethyl more than methyl analogues of Cardona® (2-chloro-l-(2,4,5-trichlorophenyl) vinyl dimethyl phosphate). Monochlorovinyl analogues were more toxic than their corresponding dichlorovinyl analogues, but the latter could be synergized more. Although some ethyl analogues of phosphorothioates could be synergized, the degree of synergism was relatively low. Among methyl analogues of phosphorothioates, synergist reduced their toxicity, indicating that ethyl analogues may be more susceptible to oxidative metabolism than corresponding methyl analogues. Based on toxicity and the degree of synergism, p-chloro-substitution of the phenyl ring was least subjected to metabolic detoxification. A 2,5-dichloro-4-nitrophenyl analogue was synergized 64 times. From several combinations, the results indicated that low-toxic members could be synergized more than highly toxic members. The differences in toxicity between closely related structures were much less with than without synergist.

All hough the relationship between laboratory toxicity data and field performance of pesticides is generally unexplored, the knowledge of such correlation would be valuable for the evaluation of new compounds. After trying various means of correlation, the following mathematical model has been derived by the method of least squares for the calculation of 215 pairs of comparisons of 15 insecticides tested against several leaf-feeding insect pests. log Y = ─0,0041 + 0.4875 log X Where X is the relative toxicity of a compound in the laboratory against a standard and expressed as the ratio of toxicity indexes and Y is the relative performance of the same compound against the same standard and expressed as the ratio of field dosages. A good degree of correlation was obtained between laboratory and field data. when experimental data were substituted into the above equation the calculated dosages for demeton, diazinon, naled, azinphosmethyl, malathion, methyl parathion, mevinphos, Aramite® [2 (p-tert-butylphenoxy) isopropyl-2-cbloroethyl sulfite], dieldrin, DDT, SD 3110 (5,6,7,8,9-hexa-chloro-1,4,4a,5,8,8a-hexahydro-1,4:5,8-dimethanophthalazine), SD 3450 (N-oxide of SD 3110), isobenzan, and carbaryl agree fairly well with their recommended field dosages for control of two-spotted spider mites, Tetranychus urticae (Koch); pea aphids, Acyrthosiphon pisum (Harris) ; corn earworms, Heliothis zea (Boddie); and/or devastating grasshoppers, Melanoplus devastator Scudder. This equation may be used also for calculating approximate field dosages for candidate insecticides and for selecting laboratory test methods for screening new compounds.

Based on a combination of several physical properties of insecticides, a new bioassay technique has been developed. This method consists of depositing insecticide and kerosene on a filter paper in a petri dish and confining insects in another dish separated from the first by another filter paper. At 2-hour exposure and with 10 mg. of kerosene in each deposit., interferences of 25 organophosphorus, 16 chlorinated, and 3 carbamate insecticides are less than 1% of apparent DDVP. Radioassay of carbon-14 DDVP and gas-liquid chromatographic analysis of aldrin support the hypothesis for the mechanism of this technique.

Azodrin® insecticide (3-hydroxy-N-methyl-cis-crotonamide dimethyl phosphate) and 6 homologues were tested against Musca domestica L. by topical application, injection, infusion, and oil-spray methods with and/or without a synergist. Their observed toxicities obtained by different testing methods generally decreased from low to high homologues. When the results obtained by topical application and injection methods are compared on the same basis, the difference in toxicities is about 340 times between-NH2 and -NHC8H17 homologues by topical application, and only 2.8 times (M ratio) by injection of flies pretreated with sesamex (synergist) This tremendous change of observed toxicity indicates that by injecting toxicants into flies pretreated with sesamex, the potential toxicity of compounds can be more fully indicated; however, some detoxication may still occur in the higher homologues. Since homologues of Azodrin insecticide are partitioned more favorably into water than into hexane, the decrease in toxicity by an infusion method, as compared with injection results, is more likely due to detoxication than to partition into lipids. Thus the difference in toxicity between infusion and injection methods would indicate the degree of instability of these compounds in house flies and should correlate with the degree of synergism. When the degree of synergism of Azodrin homologues was plotted against the LD50 ratio of infusion and injection on log-log scales, a straight-line relationship was obtained. Further study on the interaction between physical, chemical, and biological factors is necessary for a better understanding of the relationship between structure and activity.