[Electroencephalographic differences in patients with paranoid schizophrenia with or without a history of suicide attempts]. / Elektroentsefalograficheskie razlichiya u bol'nykh paranoidnoi shizofreniei s nalichiem ili otsutstviem suitsidal'nykh popytok v anamneze.

OBJECTIVE: To identify differences in electroencephalographic parameters in schizophrenia patients with and without a history of suicide attempts. MATERIAL AND METHODS: Eighty-seven inpatients (50 men and 37 women) with paranoid schizophrenia were examined. Suicidal attempts in the anamnesis of patients were verified by a psychiatrist on the basis of clinical interviewing. The severity of psychopathological symptoms was assessed using The Positive and Negative Syndrome Scale (PANSS) based on a five-factor model. Electroencephalogram (EEG) parameters were recorded and evaluated using a 16-channel encephalograph. A clinical and quantitative analysis of the recordings was carried out with the calculation of absolute spectral power indicators for theta, alpha and beta rhythms, as well as the severity of the activation reaction (Berger effect). RESULTS: Significantly higher rates of the PANSS depression factor were revealed in patients with a history of suicide attempts (p=0.016). Clinical analysis of EEG changes did not reveal any significant differences between the groups (p>0.05). The spectral analysis of the EEG showed significant differences only in the spectral power of the beta rhythm in the central (p=0.048) and occipital (p=0.021) leads with closed eyes, which was lower in the group with a history of suicide attempts. The degree of alpha rhythm depression in the occipital leads was also significantly lower in this group (p=0.016). The regression analysis showed that significant correlates of suicidal attempts in patients with paranoid schizophrenia are the PANSS depressive factor (t=2.784; p=0.016) and a deficiency in the activation response to EEG (t=-2.035; p=0.045). CONCLUSION: The results complement previous studies on the relationship between suicidal attempts, clinical symptoms and neurophysiological features of the functioning of the brain of patients with paranoid schizophrenia.

[Cerebral hemodynamic disorders in patients with schizophrenia with concomitant metabolic syndrome]. / Tserebral'nye gemodinamicheskie narusheniya u bol'nykh shizofreniei s metabolicheskim sindromom.

OBJECTIVE: To identify the differences or comparability of parameters of cerebral hemodynamics between patients with schizophrenia with or without concomitant metabolic syndrome (MS). MATERIAL AND METHODS: The study included 94 patients with schizophrenia (48 men and 46 women). A control group consisted of 40 mentally and somatically healthy individuals (17 men and 23 women) comparable in sex and age to the main group of patients. The diagnosis of metabolic syndrome was carried out according to the criteria of the International Diabetes Federation (IDF). Assessment of cerebral hemodynamics was carried out by 4 - channel rheoencephalography (REG) at rest with closed eyes. Data analysis was carried out using the Kraskel-Wallis ANOVA criterion with the procedure of automatic a posteriori pairwise comparison, the χ2 criterion and Spearman correlation analysis. RESULTS: According to the IDF criteria, 37 (39.4%) patients were diagnosed with MS. REG results revealed significantly (p<0.05) lower indicators of blood filling in the carotid basin, elasticity of the wall of the main arteries, the tone of small-caliber arteries and arterioles, as well as higher values of the tone of medium-caliber arteries in the carotid and vertebrobasilar basins, in both groups of patients with schizophrenia compared with the control group. In patients with schizophrenia with MS, compared with patients without MS, there were lower indicators of blood filling (p=0.044 and p=0.016) and elasticity of the wall of the main arteries (p=0.044 and p=0.028) in the carotid basin on the left and right sides. CONCLUSION: The presence of MS in patients with schizophrenia was accompanied by more pronounced disorders of cerebral blood flow in the form of a decrease in blood filling and elasticity of the wall of the main arteries in the carotid basin. The results indicate that patients with schizophrenia with MS should be considered as a group at increased risk of cerebrovascular diseases.

[The relationship between the functional state of the brain and clinical and constitutional factors in schizophrenia]. / Svyaz' funktsional'nogo sostoyaniya golovnogo mozga s klinicheskimi i konstitutsional'nymi faktorami pri shizofrenii.

OBJECTIVE: To establish the relationships of functional changes of the brain of patients with schizophrenia with clinical manifestations of the disease and their constitutional and morphological features. MATERIAL AND METHODS: One hundred and eighteen patients with schizophrenia (64 men and 54 women), aged 33 [29; 40], years were examined. The following clinical and dynamic parameters were used: age of manifestation of the disease, duration of the disease, severity of clinical and psychopathological symptoms according to the PANSS. The anthropometric examination of patients was carried out according to V.V. Bunak's method in V.P. Chitetsov's modification for adult samples with calculation of Rees-Eysenk and Tanner indices. The EEG was recorded and analyzed in a state of calm, relaxed wakefulness with closed eyes with the calculation of the absolute spectral power for theta (4-7 Hz), alpha (8-13 Hz) and beta (14-30 Hz) rhythms. RESULTS: Significant (p<0.05) direct correlations between the age of the disease manifestation and the spectral power of the beta rhythm in the frontal leads (Fp1, Fp2, F3 and F4) were revealed. Inverse correlations (p<0.05) were found between the duration of the disease in patients with schizophrenia and the spectral power of the alpha rhythm in the left temporal (T3) and right central leads (C4), the spectral power of the beta rhythm in the parietal-occipital (P3, P4, O1,O2) and temporal leads (T3, T4, T5), the spectral power of the theta rhythm in the left occipital (O1) and posterior temporal leads (T5). Significant inverse correlations were also found between the Tanner index and the spectral power of the alpha rhythm in the frontal and temporal leads, between the Rees-Eysenk index and the spectral power of the theta rhythm in the frontal leads. CONCLUSION: The results indicate the presence of the conjugation of functional changes in the brain of patients with schizophrenia with clinical manifestations of the disease and their constitutional and morphological features. Thus, the assessment of the functional state of the central nervous system in patients with schizophrenia is an important component of the diagnostic search.

[Associations between components of metabolic syndrome and cognitive impairment in patients with schizophrenia]. / Svyazi mezhdu komponentami metabolicheskogo sindroma i kognitivnymi narusheniyami u bol'nykh shizofreniei.

OBJECTIVE: To study the relationship between the individual components of the metabolic syndrome and cognitive dysfunction in patients with schizophrenia. MATERIAL AND METHODS: A total of 133 patients with schizophrenia were examined. To assess cognitive functioning, the Brief Assessment of Cognition in Schizophrenia (BACS) was used. The components of the metabolic syndrome were determined in accordance with the criteria of the International Diabetes Federation. RESULTS: Hyperglycemia in patients with schizophrenia led to a decrease in cognitive functioning in two domains: verbal fluency (ß=-10.67; p=0.019) and attention stability (ß=-9.519; p=0.043). Abdominal obesity was associated with lower indicators of executive functions (ß=-8.856; p=0.026). CONCLUSION: It is assumed that drug treatment of some components of the metabolic syndrome may affect cognitive functions in patients with schizophrenia.

[Features of decision-making in patients with alcohol dependence]. / Osobennosti prinyatiya reshenii u bol'nykh alkogol'noi zavisimost'yu.

OBJECTIVE: To identify electroencephalographic correlates of decision-making features in patients with alcohol dependence. MATERIAL AND METHODS: Forty men with alcohol dependence were examined as the main group. Thirty people were examined as a control group. The Cambridge Gambling Task and the Iowa Gambling Task were used to study decision-making functions. Additionally, a background electroencephalogram was recorded with the calculation of absolute spectral power indicators. RESULTS: In the main group, the relatively higher indicators of decision-making logic (65 [50; 80]%, p<0.05) were associated with larger values of the spectral power of the theta and alpha rhythm of the electroencephalogram in the central and parietal-occipital leads (R=0.426, p=0.019; R=0.418, p=0.022; R=0.394, p=0.028 and R=0.445, p=0.014; R=0.458, p=0.011; R=0.382, p=0.035, respectively). Difficulties in making decisions based on emotional learning in patients with alcohol dependence were associated with larger values of the spectral power of the beta rhythm of the electroencephalogram in the temporal leads. CONCLUSIONS: The study showed that the deficit of decision-making functions in patients with alcohol dependence may be due to an imbalance of the excitation/inhibition mechanisms in the brain.

[Disorders of cognitive decision-making mechanisms related to reward in alcohol use disorders]. / Narusheniya kognitivnykh mekhanizmov prinyatiya reshenii, svyazannykh s voznagrazhdeniem, pri alkogol'noi zavisimosti.

OBJECTIVE: To assess the relationship of disorders of cognitive decision-making mechanisms related to reward with clinical indicators of alcohol dependence. MATERIAL AND METHODS: Forty-five patients with alcohol dependence were studied. A control group consisted of 30 age- and sex-matched healthy individuals. To quantify cognitive functions, the Go/NoGo task, the Balloon test (BART), the Cambridge Game Task (CGT) and the Iowa Game task (IGT) were used. The age of the first alcohol sample, the age of the beginning of systematic alcohol abuse, the average amount of alcohol consumption over the past month, the number of hospitalizations, the age of the first visit to a narcologist and the duration of the last remission were used as clinical indicators. RESULTS: The indicators of executive functions are significantly reduced in patients with alcohol dependence compared with the control group. In the Go/NoGo task, patients have more errors, both on the Go signal (p=0.012) and on the NoGo signal (p=0.009). Significant differences in the group of patients with alcohol dependence from the control group were also revealed in CGT: patients had lower values of decision quality (QDM) (p=0.002), higher values of risk acceptance (OBR) (p=0.015), and they also needed more time to make decisions (DT) (p=0.012). It was also found that the age of the onset of systematic alcohol abuse directly correlates with the quality of decision-making in CGT (rs=0.407, p=0.048). CONCLUSION: The results emphasize the importance of studying cognitive impairment in patients with alcohol dependence, since the severity of these disorders is associated with the clinical course of the disease.

[Coherence of the electroencephalogram and peripheral markers of nerve tissue damage in depressive disorders]. / Kogerentnost' elektroentsefalogrammy i perifericheskie markery povrezhdeniya nervnoi tkani pri depressivnykh rasstroistvakh.

OBJECTIVE: To evaluate the coherence parameters of the electroencephalogram and the level of peripheral markers of nerve tissue damage in patients with depressive disorders. MATERIAL AND METHODS: Thirty patients with a diagnosis from a cluster of mood disorders: affective disorder within a single depressive episode and recurrent depressive disorder were examined. A control group consisted of 30 healthy individuals, comparable in sex and age to the main group. The bioelectric activity of the brain was recorded and analyzed with the calculation of the averaged coefficients of intra- and interhemispheric coherence. The concentration of calcium-binding protein S100b, the main protein of myelin MBP and glial fibrillar acid protein GFAP was determined in blood sera by solid-phase enzyme immunoassay. RESULTS: Patients with depressive disorders showed signi cantly lower coefficients of interhemispheric coherence of alpha (p=0.003), beta (p=0.042) and theta rhythms (p=0.041), as well as intrahemispheric coherence of alpha rhythm in the left (p=0.016) and right hemispheres (p=0.026), beta rhythm in the right hemisphere (p=0.034) compared to the control group. Patients with depressive disorders showed a higher concentration of MBP compared to the control group (p=0.008). Additionally, we identified statistically significant correlations between EEG coherence coefficients and serum markers in patients with depressive disorders. CONCLUSION: The results clearly confirm the presence of inflammatory changes in the brain in patients with depression, which is reflected in structural and functional changes.

[Features of the reward-based decision-making in patients with alcohol use disorders]. / Osobennosti kognitivnogo protsessa prinyatiya reshenii, osnovannykh na voznagrazhdenii, u bol'nykh alkogol'noi zavisimost'yu.

Foreign studies increasingly emphasize the role of reward-based cognitive decision-making and its contribution to alcohol and drug abuse. Unfortunately, such studies are extremely few in Russia. Given the importance of the insufficiency of cognitive functions, primarily the decision-making process based on reward, among the risk factors of addictive pathology, increasing the severity of alcoholism, reducing the effectiveness of its therapy and rehabilitation, research in this direction is extremely relevant. This review summarizes and systematizes current data on the features of the cognitive decision-making process based on reward in patients with alcohol dependence. An analysis of the literature has shown that reward-based decision making is an important component of addictive behavior. Patients with alcohol dependence, as well as people, who abuse alcohol, demonstrate clear impairment of this cognitive function. Thus, the relative value of diagnosing disorders in decision-making in modern psychiatry is beyond doubt. It is recommended to include the above tests in the diagnostic complex of a psychiatrist, along with standard psychometric tools.

[The differential diagnosis of unipolar and bipolar depression based on EEG signals]. / Rol' elektroentsefalografii v differentsial'noi diagnostike unipolyarnoi i bipolyarnoi depressii.

The relevance of timely detection and differential diagnosis of depressive disorder and bipolar affective disorder (BD) is beyond doubt. In complex differential diagnostic cases, clinicians can come to the aid of objective research methods, such as electroencephalography. This review summarizes and systematizes modern methods of differential diagnosis of unipolar and bipolar depression based on electroencephalography data. A literature search was conducted using the search terms «depression¼, «bipolar disorder¼, «unipolar depression¼, «differential diagnosis¼, «neuromarkers¼, «electroencephalography¼, «quantitative EEG¼. The search was conducted in the databases PubMed, NCBI, ResearchGate, RSCI, Scopus and Google Scholar in the period 2000 to 2022. In general, EEG indicators at rest in patients are characterized by ambiguity and require further clarification, however, there are some important findings on the differences in the asymmetry of electric activity, spectral power and coherence between patients with BD and unipolar depression. As for event-related potentials (ERP), similar results were obtained in a number of studies. There are a longer latency of P300 and a decrease in its amplitude in patients with BD compared to unipolar depression, which makes the ERP method more promising in solving the problem of differential diagnosis.

[Cerebral hemodynamics and executive functioning in patients with alcohol use disorders]. / Tserebral'naya gemodinamika i ispolnitel'noe funktsionirovanie u bol'nykh s alkogol'noi zavisimost'yu.

OBJECTIVE: To study the cerebral hemodynamics and executive functioning in patients with alcohol use disorders. MATERIAL AND METHODS: We studied 58 patients with alcohol use disorders aged 30 to 55 years and 40 healthy controls. Rheoencephalography was used to detect cerebrovascular changes. Executive functioning was assessed using the Go-No-Go, Corsi, and Color Stroop tests. RESULTS: Patients with alcohol use disorders have higher values of the tone of resistive vessels and medium - caliber arteries, as well as lower indicators of volumetric pulse blood filling and elastic properties of the main arteries in both right and left leads compared with the controls (p≤0.003). Patients with alcohol dependence had lower rates in all studied cognitive tests compared to the norm (p≤0.011). We also found statistically significant correlations between the studied parameters in patients with alcohol use disorders: a decrease in volumetric pulse blood filling correlated with impaired psychomotor response in the Go-No-Go task (errors on the Go signal) (rs=-0.36; p=0.048), as well as cognitive flexibility in the Stroop test (rs=-0.40; p=0.024). CONCLUSION: Disturbances of the psychomotor reaction and cognitive flexibility in alcohol dependence are due to the regional changes (decrease) in cerebral blood flow, as well as to a decrease in the elasticity of the wall of cerebral vessels.

[Quantitative characteristics of the alpha-band of the electroencephalogram in people with alcohol dependence]. / Kolichestvennye kharakteristiki al'fa-ritma elektroentsefalogrammy u lits s alkogol'noi zavisimost'yu.

OBJECTIVE: To study the quantitative characteristics of the alpha-band in patients with alcoholism, depending on the main clinical and dynamic characteristics of the disease. MATERIAL AND METHODS: A total of 76 patients, aged 24 to 55 years, with alcohol dependence were examined. Forty-five healthy individuals were examined as a control group. Recording and analysis of the electric activity of the brain was carried out using a 16-channel encephalograph in a state of calm wakefulness with closed and open eyes. The values of the absolute spectral power of the alpha-band were analyzed, the microstructure of the alpha spindle and the alpha band reactivity index were evaluated. RESULTS: The values of the spectral power of the alpha-band with closed eyes were statistically significantly lower in patients with alcohol dependence in all leads (p<0.05), except for the antero-temporal and mid-temporal. The microstructure of the alpha spindle in patients with alcohol dependence was mainly represented by a flat (59.2%) or low-amplitude (28.9%) type with a predominance of an accelerated band (40.8%). The degree of alpha-band depression in the leads P3 (p=0.043), P4 (p=0.047), O2 (p=0.039), T5 (p=0.037) and T6 (p=0.002) was significantly less pronounced in patients with alcohol dependence compared to the control group. CONCLUSION: The results of the study indicate that some aspects of addictive behavior are accompanied by significant objective functional changes in the brain.

[Current methods for predicting therapeutic response in patients with depressive disorders]. / Sovremennye metody prognoza terapevticheskogo otveta u patsientov s depressivnymi rasstroistvami.

Depressive disorder is the most common mental illness, which is also one of the leading causes of disability worldwide. In addition, most suicides are associated with depression. Despite all modern achievements in the treatment of depressive disorders, up to 60% of patients did not adequately respond to psychopharmacotherapy (non-responders). Current guidelines and studies characterize non-responders as patients who have an inadequate response to taking two or more antidepressants from different classes within 4 weeks. However, in some cases, such a long wait for a therapeutic response can lead to adverse consequences. Thus, there is a need to develop prognostic methods of therapeutic resistance in patients with depressive disorders. The purpose of this review is to summarize current methods used to predict therapeutic response in patients with depressive disorders. A literature search was conducted using the search terms «depression¼, «antidepressant¼, «outcome¼, «predictor¼, «(bio) marker¼, «treatment-resistant depression¼ and «chronic depression¼. The search was conducted in the PubMed, Scopus, and Google Scholar databases for the time period from 2005 to 2020.

[Features of the parameters of hemodynamics and vascular tone of the brain in patients with depressive disorders]. / Osobennosti parametrov gemodinamiki i tonusa sosudov golovnogo mozga u patsientov s depressivnymi rasstroistvami.

OBJECTIVE: To study the features of hemodynamics and vascular tone of the brain in patients with depressive disorders. MATERIAL AND METHODS: Fifty-four patients with depressive disorders and 54 conditionally healthy individuals were examined. The study of hemodynamics and vascular tone of the brain was carried out using rheoelectroencephalography. RESULTS: Patients with depression in conditions of physiological rest have a statistically significantly higher tone of resistive vessels and medium-caliber arteries, as well as a lower level of elastic properties of the main arteries compared to healthy individuals. CONCLUSION: The shape of the rheoelectroencephalogram of patients with depressive disorders was characterized by smoothing of the dicrotic wave and its displacement to the top, as well as a slight severity of incisure and an increase in the speed of propagation of the rheographic wave.

[The role of functional brain activity in the impairment of inhibitory control in alcohol dependence]. / Rol' funktsional'noi aktivnosti mozga v narushenii ingibitornogo kontrolya pri alkogol'noi zavisimosti.

OBJECTIVE: Determination of differences in brain function in alcohol-dependent patients with varying degrees of inhibitory control impairment. MATERIAL AND METHODS: Seventy-five patients with alcohol dependence were examined. The level of inhibitory control was assessed using the Go/No-go test. The background electric activity of the brain was recorded, and the values of spectral power and coherence of theta, alpha, and beta rhythms were analyzed. Two groups of patients - 24 with- and 51 without inhibitory control impairment - were determined. RESULTS: According to the spectral analysis, high values of alpha rhythm in the frontal-central-parietal-occipital and beta rhythm in the central and left occipital cortex, low values of theta rhythm in the posterior-temporal regions were common for patients with inhibitory control impairment. Visual analysis of the EEG in patients with inhibitory control impairment shows a smoothing of zonal differences in the alpha rhythm, which is not found in patients without the disturbance of inhibitory control. Patients with inhibitory control impairment were characterized by an increase in interhemispheric connections in the alpha and beta frequency ranges and a weakening of intrahemispheric connections on the right in the theta rhythm range. CONCLUSION: There are significant differences in the functioning of the brain in patients with alcoholism, depending on the presence / absence of inhibitory control impairment.

Correlation of Antibodies to Neurotransmitters in the Sera of Women with Alcohol Dependence and Depressive Disorders.

Comparative analysis of blood sera from women with alcohol dependence and depressive disorders or from conditionally healthy women revealed reduced level of antibodies to dopamine, norepinephrine, serotonin, glutamate, and GABA in blood serum in women with dysthymic disorder and a depressive episode and their increased content in women with alcohol dependence in combination with depressive disorders.

[Executive functions and their role in predicting therapeutic response in patients with depressive disorders]. / Upravlyayushchie kognitivnye funktsii i ikh rol' v prognozirovanii terapevticheskogo otveta u patsientov s depressivnymi rasstroistvami.

OBJECTIVE: To identify differences in executive functions in patients with depressive disorders depending on their sensitivity to antidepressants. MATERIAL AND METHODS: The study included 70 patients with depressive disorder. All patients received syndrome-induced psychopharmacotherapy, which included antidepressants and normotimics. The severity of depressive disorder was assessed using the Hamilton Depression Rating Scale (HDRS). The criterion for the effectiveness of therapy (sensitivity) was an improvement in clinical symptoms by 50% or more, as measured with HDRS. The study was performed in two stages (points): at the first point, patients were examined upon admission to the Department before taking medications, and the second point was performed after a 4-week treatment of patients in the hospital. The assessment of executive functions was performed using computer tests Go/Nogo, Corsi and Stroop. RESULTS AND CONCLUSION: Patients with depressive disorders who were not sensitive to therapy were characterized by low performance in executive functions compared to patients with a positive therapeutic response. Based on the data obtained, a multiple linear regression equation was constructed to predict the therapeutic response based on individual differences in the results of cognitive tests, regardless of potential clinical and demographic factors.

[Clinical and electrophysiological parameters of alcohol dependence and its comorbidity with affective disorders]. / Klinicheskie i neirofiziologicheskie osobennosti pri alkogol'noi zavisimosti i pri ee komorbidnosti s affektivnymi rasstroistvami.

OBJECTIVE: To identify characteristics of and possible differences in clinical and electroencephalographic parameters in patients with alcohol dependence with- and without comorbid affective disorders. MATERIALS AND METHODS: Ninety-five patients, including 74 with an established diagnosis of alcohol dependence and 21 with alcohol dependence and affective disorders, were examined. Duration of alcohol dependence and affective disorder (years), number of hospitalizations and suicidal attempts were analyzed as anamnestic data. Hamilton's anxiety and depression scale (HDRS), the Alcohol Use Disorders Identification Test (AUDIT), the General clinical impression scale (CGI-s) were used as psychometric tools. The study of bioelectric activity of the brain was carried out using a 16-channel encephalograph. The background electroencephalogram was recorded, the values of absolute spectral power and coherence of theta, alpha and beta rhythms were analyzed. RESULTS AND CONCLUSION: Patients with comorbidity of alcohol dependence and affective disorders have a significantly higher risk of suicidal behavior, a greater frequency of hospitalizations, higher levels of anxiety compared with patients without affective disorders. Electrophysiological data have shown that patients with comorbidity of alcohol dependence and affective disorders have higher values of spectral power of alpha-rhythm in all parts of the cerebral cortex (except for temporal lobes) and beta-rhythm in the occipital cortex, as well as an increase in interhemispheric coherence in all frequency ranges.

[Disorders of spatial working memory in affective disorders with mild current depression and their neurophysiological correlates]. / Narusheniia funktsii prostranstvennoi rabochei pamiati pri depressii legkoi stepeni tiazhesti i ikh neirofiziologicheskie korreliaty.

AIM: To assess spatial working memory disorders in patients with mild depressive disorders and determine their neurophysiological correlates. MATERIAL AND METHODS: Thirty patients (right-handed) with ICD-10 diagnosis Mood Disorders (F31.3, F32.0, F33.0, F34.1), aged 37±8 years, were examined before treatment. A control group included 30 mentally and somatically healthy individuals (32±7 years old). The study of spatial working memory was carried out using the Corsi Block-Tapping test. EEG was recorded and the values of the spectral power of theta, alpha and beta rhythms were analyzed. RESULTS AND CONCLUSION: A decrease in the level of working memory that was correlated with higher values of theta rhythm power in the frontal and occipital regions and alpha rhythm in the frontal cortex was observed in affective disorders with mild depressive symptoms.

Integrated modeling of electron cyclotron resonance ion sources and charge breeders with GEM, MCBC, and IonEx.

A numerical toolset to help in understanding physical processes in the electron cyclotron resonance charge breeder (ECRCB) and further to help optimization and design of current and future machines is presented. The toolset consists of three modules (Monte Carlo charge breeding code, generalized electron cyclotron resonance ion source modeling, and ion extraction), each modeling different processes occurring in the ECRCB from beam injection to extraction. The toolset provides qualitative study, such as parameter studies, and scaling of the operation, and physical understanding in the ECRCB. The methodology and a sample integrated modeling are presented.

IONEX: a meshfree ion extraction code based on "particle in cloud of points" concept.

Ion Extraction (IONEX) is an ion extraction modeling code, developed at FAR-TECH, Inc., based on the meshless particle-in-cloud-of-points concept. IONEX self-consistently solves motion equations for ions and Poisson's equation for the electrostatic field, assuming a Boltzmann distribution for the electrons. IONEX is capable of handling multiple species and is graphical user interface-driven. The two-dimensional version is benchmarked with IGUN. The basic algorithm and sample runs are presented.