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2022

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Full-Text Articles in Chemistry

Investigating The Nuclear Properties Of 162-172 Er Isotopes Using Ibm-1, Sef, And Nee, Amal M. Al-Nuaimi, R.B. Alkhayat, Mushtaq Abed Al-Jubbori Aug 2022

Investigating The Nuclear Properties Of 162-172 Er Isotopes Using Ibm-1, Sef, And Nee, Amal M. Al-Nuaimi, R.B. Alkhayat, Mushtaq Abed Al-Jubbori

Karbala International Journal of Modern Science

The energy levels of the ground state band (GSB), , and γ-bands for 162-172Er isotopes are calculated in this work by adopting the Interacting Boson Model (IBM-1), the Semi-Empirical Formula (SEF) and the New Empirical Equation (NEE). The GSB, , and γ-bands results revealed that IBM-1, SEF, NEE, and the available experimental data are all in agreement with certain variations. The NEE is more compatible with the experimental data than the IBM-1 and SEF calculations. This study demonstrates that the SEF and NEE equations are able to describe the energy spectra of Er isotopes in comparison to IBM-1. The Er …


Antimicrobial And Cytotoxic Properties Of Extracts From Over-Seasoned Worm-Casts Of The Earthworm Hyperiodrilus Africanus Beddard, 1891, Stephen Olugbemiga Owa, David Adeiza Otohinoyi, Theresa Ibibia Edewor-Ikupoyi, Adeolu Adeola Taiwo, Jenifer Akhere Okosun, Yvonne Oluchi Akujobi, Damilola Grace Oyewale, Tomilola Debby Olaolu, Damilare Emmanuel Rotimi, Osarenkhoe Omorefosa Osemwegie, Oluyomi Stephen Adeyemi Aug 2022

Antimicrobial And Cytotoxic Properties Of Extracts From Over-Seasoned Worm-Casts Of The Earthworm Hyperiodrilus Africanus Beddard, 1891, Stephen Olugbemiga Owa, David Adeiza Otohinoyi, Theresa Ibibia Edewor-Ikupoyi, Adeolu Adeola Taiwo, Jenifer Akhere Okosun, Yvonne Oluchi Akujobi, Damilola Grace Oyewale, Tomilola Debby Olaolu, Damilare Emmanuel Rotimi, Osarenkhoe Omorefosa Osemwegie, Oluyomi Stephen Adeyemi

Karbala International Journal of Modern Science

⦁ Background: Despite the continuous interest in the search for therapeutic agents, little attention has been given to the medicinal relevance of earthworm casts, with even less interest in over-seasoned worm-casts. Therefore, this study determined the phytochemical, antimicrobial, and cytotoxic properties of over-seasoned worm-casts of the earthworm Hyperiodrilus africanus (Eudrilidae). Methods: The earthworm casts were extracted with n-hexane, ethanol, and water and the crude extracts were evaluated for the presence of chemical constituents and antimicrobial properties. Cytotoxicity was inferred from the antimitotic effects of the extracts on the radicles of germinating seeds of Sorghum bicolor. Results: The chemical constituent determinations …


A Review On The Ethnobotanical, Phytochemistry, And Pharmacological Activities Of Aristolochia Longa L., Oluwafemi Adeleke Ojo, Matthew Iyobhebhe, Bukola Atunwa, Adebola Busola Ojo Aug 2022

A Review On The Ethnobotanical, Phytochemistry, And Pharmacological Activities Of Aristolochia Longa L., Oluwafemi Adeleke Ojo, Matthew Iyobhebhe, Bukola Atunwa, Adebola Busola Ojo

Karbala International Journal of Modern Science

Aristolochia longa L. is a plant native to Algeria and Morocco that has been used by the locals to combat different arrays of infections and diseases found among them. This particular plant is well-known for its therapeutic qualities that could be traced back to the presence of many effective phytochemicals that have been extrapolated from the different parts of the plant, like the leaves and roots: flavonoids, saponins, tannins, 4-hydroxybenzoic acid, β-carotenes, limonenes, and palmitic acids. This plant has been identified in different research articles to be able to manage diseases effectively because it possesses some pharmacological attributes such as; …


Applicability Limits Of The End Face Fiber-Optic Gas Concentration Sensor, Based On Fabry-Perot Interferometer, S.M.R.H. Hussein, A.Zh. Sakhabutdinov, O.G. Morozov, V.I. Anfinogentov, J.A. Tunakova, A.R. Shagidullin, A.A. Kuznetsov, K.A. Lipatnikov, A.R. Nasybullin Aug 2022

Applicability Limits Of The End Face Fiber-Optic Gas Concentration Sensor, Based On Fabry-Perot Interferometer, S.M.R.H. Hussein, A.Zh. Sakhabutdinov, O.G. Morozov, V.I. Anfinogentov, J.A. Tunakova, A.R. Shagidullin, A.A. Kuznetsov, K.A. Lipatnikov, A.R. Nasybullin

Karbala International Journal of Modern Science

The mathematical model of the fiber-optic sensor for gas concentration analysis is under study. The sensor is imple-mented as Fabry-Perot interferometer at the end face of the optical fiber by applying a thin polymer film, which permit-tivity depends on the tested gas concentration. It is shown, that a change in the properties of the optical fiber or the at-mosphere permittivity leads mainly to the spectrum contrast changing and does not change the period and the wave-length shift of its comb. The influence of the polymer film thickness, the environment temperature and humidity on the Fabry-Perot spectrum is analyzed. The necessity …


Molecular Docking Reveals Phytoconstituents Of The Methanol Extract From Muntingia Calabura As Promising Α-Glucosidase Inhibitors, Nurlena Andalia, Muhammad N. Salim, Nurdin Saidi, Muhammad Ridhwan, Muhammad Iqhrammullah, Ummu Balqis Aug 2022

Molecular Docking Reveals Phytoconstituents Of The Methanol Extract From Muntingia Calabura As Promising Α-Glucosidase Inhibitors, Nurlena Andalia, Muhammad N. Salim, Nurdin Saidi, Muhammad Ridhwan, Muhammad Iqhrammullah, Ummu Balqis

Karbala International Journal of Modern Science

Inhibition of α-glucosidase has been used as a management of type 2 diabetes mellitus, where studies are focused on finding more efficacious and safe drugs. Herein, the research aimed to unveil the potential of phytoconstituents contained in methanol extract of Muntingia calabura leaves in inhibiting α-glucosidase through molecular docking simulation. From a systematic search (Scopus), we found 5 eligible articles and identified 28 phytocompounds. Fisetin, pinostrobin, and rhamnetin identified in M. calabura extract were predicted to have good bioavailability. Finally, fisetin was revealed as the most potential α-glucosidase inhibitor candidate with a binding affinity of -7.5 kcal/mol.


How Dynamic Bond Results In The Unique Viscoelastic Behavior Of The Associating Polymers, Sirui Ge Aug 2022

How Dynamic Bond Results In The Unique Viscoelastic Behavior Of The Associating Polymers, Sirui Ge

Doctoral Dissertations

Associating polymer is a special kind of polymer possessing transient reversible bonds in addition to the conventional covalent bonds. The reversible bonds provide unique dynamics and fascinating viscoelastic properties, resulting in attractive applications for these polymers, such as self-healing and shape memory materials. Despite many years of studies, the understanding of dynamics of polymers with reversible bonds, especially on molecular level, is still in the rudimentary stage, preventing the rational design of the potential novel functional materials based on associating polymers. In this dissertation, we provide a detailed and quantitative understanding of the dynamics and viscoelastic properties of associating polymers. …


College Of Natural Sciences Newsletter, July & August 2022, College Of Natural Sciences Aug 2022

College Of Natural Sciences Newsletter, July & August 2022, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 3, Issue 5

Page 1 Dean's Message
Page 2 Awards & Recognition
Page 3 Resources for Student Success
Page 4 Welcome to New Faculty & Staff
Page 5 Summer Activities in CNS
Page 9 Celebrating the lives of those who touched the College
Page 10 Media Coverage of CNS
Page 12 Open PRAIRIE Data
Page 13 Snaps from he start of the semester
Page 14 Science as Art Competition




Development Of High Quantum Efficiency Strained Superlattice Spin Polarized Photocathodes Via Metal Organic Chemical Vapor Deposition, Benjamin Belfore Aug 2022

Development Of High Quantum Efficiency Strained Superlattice Spin Polarized Photocathodes Via Metal Organic Chemical Vapor Deposition, Benjamin Belfore

Electrical & Computer Engineering Theses & Dissertations

Spin polarized photocathodes are necessary to examine parity violations and other fundamental phenomena in the field of high energy physics. To create these devices, expensive and complicated growth processes are necessary. While integral to accelerator physics, spin polarized electrons could have other exciting applications in materials science and other fields of physics. In order to explore these other applications feasibly, the relative supply of spin polarized photocathodes with a high rate of both polarization and photoemission needs to be increased. One such way to increase this supply is to develop the means to grow them faster and at a larger …


Hierarchically Structured Photoelectrodes Via Atomic Layer Deposition, Justin Rowan Reed Demoulpied Aug 2022

Hierarchically Structured Photoelectrodes Via Atomic Layer Deposition, Justin Rowan Reed Demoulpied

Graduate Theses and Dissertations

In the search for a sustainable method to meet increasing energy needs, solar energy emerges as an underutilized, plentiful resource. Solar intermittency and requirements for transportation necessitate storing solar energy in the form of chemical bonds via artificial photosynthesis. Photoelectrochemical (PEC) water splitting generates hydrogen fuel from solar energy and water. A semiconducting material that successfully meets the complex requirements for building an industrially scalable PEC device has yet to emerge. This is leading to a reevaluation of materials previously overlooked within PEC research, mainly materials with limitations such as minimal charge carrier mobility and propensity to corrosion under illumination …


61st Annual Rocky Mountain Conference On Magnetic Resonance Jul 2022

61st Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 61st annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Copper Mountain, Colorado, July 25-29, 2022.


Bbt Acoustic Alternative Top Bracing Cadd Data Set-Norev-2022jun28, Bill Hemphill Jul 2022

Bbt Acoustic Alternative Top Bracing Cadd Data Set-Norev-2022jun28, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are
(a) a one-piece base for the standard kit's (Martin-style) bracing,
(b) 277 Ladder-style bracing, and
(c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.

The CADD data set for each of the three (3) top bracing designs includes …


Evaluation Of Silver Nanoparticles Attached To Methylene Blue As An Antimicrobial Agent And Its Cytotoxicity, Somon Hakimov Jul 2022

Evaluation Of Silver Nanoparticles Attached To Methylene Blue As An Antimicrobial Agent And Its Cytotoxicity, Somon Hakimov

Masters Theses & Specialist Projects

Antibiotics resistance is considered as one of the greatest public health challenges of our time. In this work, we have synthesized silver nanoparticles (Ag NPs) using pulsed liquid ablation in different medium of growth and later combined with methylene blue (MB) to evaluate its potential as an effective photodynamic therapy agent. Ag NPs were synthesized by pulsed laser ablation technique in Polyvinylpyrrolidone (PVP), citrate, and Polyvinyl alcohol (PVA). The Ag NPs were characterized using transmission electron microscopy (TEM), UV-Visible (UV-Vis), and photoluminescence (PL) spectra. Next, Ag NPs were coupled with MB and used to deactivate the Gram-negative bacteria, Escherichia coli …


Method Of Hybrid Control Based Of Dynamic Objects Of Neuro-Fuzzy Inference, Noilakhon Yakubova Jun 2022

Method Of Hybrid Control Based Of Dynamic Objects Of Neuro-Fuzzy Inference, Noilakhon Yakubova

Karakalpak Scientific Journal

The Results of interaction of the work is development of a method of control that allows simplifying, automating and unifying the process of design of the hybrid systems which are a basis of modern automation. To achieve a definite purpose, a method of control of a technical object based on the construction of an adaptive system of neuro-fuzzy inference is developed. The objects of the system of neuro-fuzzy inference are the classical and neuro-fuzzy models of control. Information exchange between models is provided by means of the developed hybrid control system. The result of the interaction of the two models …


Application Of A Synergetic Approach To The Problem Of Synthesizing An Intelligent Control System For Chemical Reactors, Komil Usmanov Jun 2022

Application Of A Synergetic Approach To The Problem Of Synthesizing An Intelligent Control System For Chemical Reactors, Komil Usmanov

Karakalpak Scientific Journal

The article deals with the synthesis of effective algorithms for controlling a chemical reactor and developed a intelligent synergistic controller for a class of indefinite nonlinear dynamic systems. A synergetic control scheme is proposed for solving the control problem for nonlinear systems. Non-linear systems with configurations and parameters that change over time require a completely non-linear model and adaptive control scheme for a practical operating environment. The synthesis of control laws is performed by the method of analytical design of aggregated controllers (ADAR).


Development Of The Implementation Of Iot Monitoring System Based On Node-Red Technology, Anvar Kabulov, Inomjon Yarashov, Salamat Mirzataev Jun 2022

Development Of The Implementation Of Iot Monitoring System Based On Node-Red Technology, Anvar Kabulov, Inomjon Yarashov, Salamat Mirzataev

Karakalpak Scientific Journal

This article describes how to design and implement a process for storing environmental information in a database using the Internet of Things. The problems that need to be solved with the help of this IoT system are the growing demand for forecasts in the world, the demand of the world market for a new sustainable method of implementing the digitization environment through the Internet of Things. The design was implemented using Arduino, Node-Red and sensors, selected when choosing a component based on the required parameters and sent to the database for monitoring and processing. A study of previous work and …


Theoretical Features Of Foreign Systems Of Preschool Education, Ayjamal Bazarbaeva Jun 2022

Theoretical Features Of Foreign Systems Of Preschool Education, Ayjamal Bazarbaeva

Karakalpak Scientific Journal

This article analyzes the features of preschool education systems in foreign countries. The positive experience and features of some systems are highlighted. Comparison of domestic and foreign systems of preschool education is carried out.


Table Of Contents Jun 2022

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.


Bbt Side Mold Assy, Bill Hemphill Jun 2022

Bbt Side Mold Assy, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set covers the design and fabrication information of the ETSU Guitar Building Project’s BBT (OM-sized) Side Mold Assy for use with the STEM Guitar Project’s standard acoustic guitar kit. The extended 'as built' data set contains an overview file and companion video, the 'parent' CADD drawing, CADD data for laser etching and cutting a drill &/or layout template, CADD drawings in AutoCAD .DWG and .DXF R12 formats of the centerline tool paths for creating the mold assembly pieces on an AXYZ CNC router, and support documentation for CAM applications including router bit specifications, feeds, speed, multi-pass …


College Of Natural Sciences Newsletter, May & June 2022, College Of Natural Sciences Jun 2022

College Of Natural Sciences Newsletter, May & June 2022, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 3, Issue 4

Page 1 Dean's Message
Page 2 Awards and Recognition
Page 3-4 The path to a Doctorate Degree
Page 4 American Indian Student Center Native Graduate Honoring Ceremony
Page 5 Celebrating the lives of those who touched the College
Page 6 Media coverage of CNS
Page 7 Open PRAIRIE
Page 8-10 CNS Graduation Festivities
Page 11-14 Spring 2022 Dean's List
Page 16 Richard and Janice Vetter Endowed Professorship in Biotechnology.position


Development Of Quantitative Methods To Study Pfas Using Proton Induced Gamma-Ray Emission, Colin Langton Jun 2022

Development Of Quantitative Methods To Study Pfas Using Proton Induced Gamma-Ray Emission, Colin Langton

Honors Theses

Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals that have become a major environmental concern. They can be found in a broad range of everyday products and pose a significant risk to the public due to their adverse health effects. They are persistent, bioaccumulate and do not break down in the environment. This project specifically aims to determine the concentration of Fluorine, a key identifier of PFAS, in environmental samples. To do this, we employ proton induced gamma-ray emission (PIGE) to screen for Fluorine within our samples. PIGE is performed at the Union College Ion Beam Analysis Laboratory using a …


Dr. Lawrence J. Berliner, Anit Tyagi May 2022

Dr. Lawrence J. Berliner, Anit Tyagi

DU Undergraduate Research Journal Archive

An interview with Dr. Lawrence J. Berliner.


Editorial Board May 2022

Editorial Board

Karbala International Journal of Modern Science

No abstract provided.


Simulating Photo-Disintegration Of 137cs Radioactive Waste Using Various Energies Of Gamma Photons, Hassanain H. Alkazzaz, Asia H. Al-Mashhadani, Kamal H. Lateef May 2022

Simulating Photo-Disintegration Of 137cs Radioactive Waste Using Various Energies Of Gamma Photons, Hassanain H. Alkazzaz, Asia H. Al-Mashhadani, Kamal H. Lateef

Karbala International Journal of Modern Science

In this study, the possibility of using gamma-ray in photo-disintegration method was examined so that it can be used in the remediation of 137Cs radionuclides waste materials by nuclear transmutation to convert long-lived nuclides to other isotopes nuclides, which are shorter half-life (or stable), by different photo-nuclear reaction channels (γ,n), (γ,2n), (γ,p), (γ, a), (γ,d). A simulation code has been written using MATLAB for conducting calculations of reduction and residual. The results showed that gamma-ray fluxes below 1017 [cm-2 s-1] are not adequate to perform effective incinera-tion of 137Cs, and as for gamma flux of 1018 [cm-2 s-1] it showed …


Engineering Of A Multi-Epitope Subunit Vaccine Against Sasrs-Cov-2 Through The Viroinformatic Approach, Aamir Shehzada, Christijogo Sumartono, Jusak Nugraha, Helen Susilowatid, Andi Yasmin Wijayab, Hafiz Ishfaq Ahmad, Wiwiek Tyasningsih, Fedik Abdul Rantam May 2022

Engineering Of A Multi-Epitope Subunit Vaccine Against Sasrs-Cov-2 Through The Viroinformatic Approach, Aamir Shehzada, Christijogo Sumartono, Jusak Nugraha, Helen Susilowatid, Andi Yasmin Wijayab, Hafiz Ishfaq Ahmad, Wiwiek Tyasningsih, Fedik Abdul Rantam

Karbala International Journal of Modern Science

The COVID-19 outbreak has infected millions of people worldwide, but no vaccine has been discovered to combat it efficiently. This research aims to design a multi-epitope vaccine using highly efficient B- and T-cell epitopes from the SARS-CoV-2 Surabaya isolate through a viroinformatic approach. First, the putative epitopes were linked together to develop tertiary structures and then docked with toll-like receptor 4 (TLR-4) that demonstrated a robust interaction with a low eigenvalue of 4.816138 e-06. Furthermore, the structure's high immunogenic response was observed and successfully cloned into the expression vector pET28a (+). This implies that the designed vaccine can prove effective …


Monitoring Bacteria Cultures Using Near Infrared (Nir) Binary Spectronephelometry (Bsn), Raman Spectra And Principal Component Analysis (Pca), Steven Ortiz May 2022

Monitoring Bacteria Cultures Using Near Infrared (Nir) Binary Spectronephelometry (Bsn), Raman Spectra And Principal Component Analysis (Pca), Steven Ortiz

Dissertations - ALL

Current noninvasive methods cannot continuously and simultaneously monitor the concentrations of cells and media components that define the state of native bacterial cultures, because of changing turbidity. A new technique, binary spectronephelometry (BSN) has the same or better sensitivity and precision for population monitoring as optical density at 600nm (OD600), while simultaneously measuring metabolic processes. The BSN algorithm uses laser induced emission to probe mildly turbid media i.e., propagation of light occurs in the single scattering regime. A BSN "training set" associates a grid of elastic emission measurements, comprising Rayleigh and Mie scattering, and inelastic emission measurements, comprising fluorescence and …


Transistion Metal Chalcogenides And Phosphides For Energy Storage And Conversion Through Water Splitting, Kelsey Thompson May 2022

Transistion Metal Chalcogenides And Phosphides For Energy Storage And Conversion Through Water Splitting, Kelsey Thompson

Electronic Theses & Dissertations

In contemporary society, there are many different ways that energy is used in daily life. From applications that require a high energy density to long-term storage in a stable manner, the requirements for energy usage are diverse. Therefore, the greater the number of uses a designed material exhibits, the more practical it may be for wide-scale manufacture. Two areas of particular interest for energy applications are fuel cells (to generate energy) and supercapacitors (to store energy). To provide cheaper and more durable alternatives for energy storage, electrodes containing CoMoO4, NiMoO4, CoMoS4, NiMoS4, …


Insights Into Molecular Recognition And Reactivity From Molecular Simulations Of Protein-Ligand Interactions Using Md And Qm/Mm, Jerrano L. Bowleg May 2022

Insights Into Molecular Recognition And Reactivity From Molecular Simulations Of Protein-Ligand Interactions Using Md And Qm/Mm, Jerrano L. Bowleg

Theses and Dissertations

In this thesis, we have employed two computational methods, molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) MD simulations with umbrella sampling (US), to gain insights into the molecular mechanism governing the molecular recognition and reactivity in several protein-ligand complexes. Three systems involving protein-ligand interactions are examined in this dissertation utilizing well-established computational methodologies and mathematical modeling. The three proteins studied here are acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1). These enzymes are known to interact with a variety of ligands. AChE dysfunction caused by organophosphorus (OP) chemicals is a severe hazard since AChE is …


Knocking Down Nox: Examining The Effects Of Transportation Electrification On Urban Ozone Production In The South Coast Air Basin, Jason Beal May 2022

Knocking Down Nox: Examining The Effects Of Transportation Electrification On Urban Ozone Production In The South Coast Air Basin, Jason Beal

Macalester Journal of Physics and Astronomy

With last year’s commitment to all in-state sales of new passenger cars and trucks being zero-emission by 2035 (California Executive Order N-79-20), California is leading the charge for transportation electrification in the United States. Despite being at the forefront of climate change management and mitigation, California has some of the worst air quality in the nation. While primarily motivated by a desire to reduce carbon dioxide emissions and reliance on fossil fuels, transportation electrification will also have a significant impact on local air quality. The goal of this study is to quantify and qualify this impact in the context of …


Theoretical Aspects Of Calculation Of Photocurrent In Structures With Periodically Spaced Heterinclusions, R. Аyukhanov, A. Uteniyazov, S. Farmonov, N. Shernazarov May 2022

Theoretical Aspects Of Calculation Of Photocurrent In Structures With Periodically Spaced Heterinclusions, R. Аyukhanov, A. Uteniyazov, S. Farmonov, N. Shernazarov

Karakalpak Scientific Journal

The processes of excitation of photoconductivity in structures with heteroinclusions with a band gap greater than the band gap of the base material of the matrix have been studied. Structures are studied when such macroinclusions are located periodically and are located at distances equal to the size of the inclusions. A technique has been developed and analytical expressions have been derived for calculating the photocurrent and specific photoconductivity in such structures.


Injection Depletion Effect In Semiconductors With Pair Impurity Complexes, A. Yu. Leyderman, A. Uteniyazov, R. Turmanova, M. Dauletbayev May 2022

Injection Depletion Effect In Semiconductors With Pair Impurity Complexes, A. Yu. Leyderman, A. Uteniyazov, R. Turmanova, M. Dauletbayev

Karakalpak Scientific Journal

The possibility of realizing the effect of injection depletion in a + -structure made on the basis of a semiconductor with paired donor-acceptor complexes is considered. It is shown that the appearance of this effect is possible under conditions of almost complete compensation of the shallow dopant donor impurity by the charge of the acceptor component of the pair complex. A necessary condition is also a strong asymmetry of the coefficients of capture of holes at the acceptor level in comparison with the coefficient of capture of electrons at the donor level.