Static Type Research Articles

Binding site identification of anticancer drug gefitinib to HSA and DNA in the presence of five different probes

This study was carried out to evaluate the binding interaction of gefitinib (GEF) with human serum albumin (HSA) and calf thymus DNA (ct-DNA) using fluorescence, UV–Visible, zeta potential measurements and molecular docking methods in order to understand its pharmacokinetic mechanism. By increasing the temperature, a steady decrease in Stern–Volmer quenching constants was observed for HSA binding properties; this indicates a static type of fluorescence quenching. Negative values were calculated for Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes, indicating that the reaction is spontaneous and enthalpy-driven. Probe competitive experimental results showed that GEF contains the same binding site as warfarin and are consistent with modeling results. The zeta potential of the HSA increased with increasing GEF, which represents the presence of electrostatic interactions in the system. DNA binding properties were investigated in the presence of three probes. The experimental results showed that by increasing GEF to DNA-AO (acridine-orange) and DNA-MB (methylene-blue) system, the fluorescence intensity and absorbance spectra had no considerable change. Furthermore, with the addition of GEF to DNA, the zeta potential decreased gradually, indicating that the hydrophobic interaction between the GEF and the bases of DNA is the major factor. Thus, GEF can bind to DNA via a groove binding mode. It was also found that GEF entered into the minor groove in the A–T rich region of DNA fragment and bind via van der-Waals forces and three H-bond with double strands of DNA. This is in good agreement with experimental results.

Dicationic imidazolium salts as fluorescent probes for selective detection of Fe3+ ion in pure aqueous media

A series of N, N’-disubstituted imidazolium salts: 3-(4-cyanobenzyl)-1-((1-(4-cyanobenzyl)pyridin-1-ium-3-yl)methyl)-2-methyl-1H-imidazolium bromide (1a), 3-(naphthalene-2-ylmethyl)-1-((-1-(naphthalene-2-ylmethyl)pyridin-1-ium-3-yl)methyl)-2-methyl-1H-imidazolium bromide (1b), 3-(4-cyanobenzyl)-1-((1-(4-cyanobenzyl)pyridin-1-ium-3-yl)methyl)-2-methyl-1H-imidazolium hexafluorophosphate (1c) and 3-(naphthalene-2-ylmethyl)-1-((-1-(naphthalene-2-ylmethyl)pyridin-1-ium-3-yl)methyl)-2-methyl-1H-imidazolium hexafluorophosphate (1d) were synthesized in good to excellent yields. The physical and chemical properties of highly water soluble bromide salts (1a and 1b) were modulated by counter anion exchange with PF6 anion (1c and 1d). These probes detect Fe (III) ion over other metal ions such as Na+, K+, Ba2+, Mn2+, Mg2+, Fe3+, Fe2+, Ca2+, Cu2+, Cr3+, Co2+, Al3+, Pb2+ and Zn2+ in aqueous media by fluorescence “turn-off” mechanism. Fluorescence quenching was also observed in the case of Fe2+, Cr3+ and Cu2+ ions to some extent. The emission intensity of probe 1a was quenched by 92% on the subsequent addition of aliquots of Fe3+ ion in pure aqueous media. Job’s plot studies of 1a-Fe3+ complex confirmed the 1:1 stoichiometry. The Stern-Volmer (S-V) plot indicates the static type of quenching mechanism at even low concentrations. The detection limit for 1a was found to be 2.81 × 10−5 M.

Secure information sharing in social agent interactions using information flow analysis

When we wish to coordinate complex, cooperative tasks in open multi-agent systems, where each agent has autonomy and the agents have not been designed to work together, we need a way for the agents themselves to determine the social norms that govern collective behaviour. An effective way to define social norms for agent communication is through the use of interaction models such as those expressed in the Lightweight Coordination Calculus (LCC), a compact executable specification language based on logic programming and pi-calculus. Open multi-agent systems have experienced growing popularity in the multi-agent community and gain importance as large scale distributed systems become more widespread. A major practical limitation to such systems is security, because the very openness of such systems opens the doors to adversaries to exploit vulnerabilities introduced through acceptance of social norms.This paper addresses a key vulnerability of security of open multi-agent systems governed by formal models of social norms (as exemplified by LCC). A fundamental limitation of conventional security mechanisms (e.g. access control and encryption) is the inability to prevent information from being propagated. Focusing on information leakage in choreography systems using LCC, we suggest a framework to detect insecure information flows. A novel security-typed LCC language is proposed to prevent information leakage.Both static (design-time) and dynamic (run-time) security type checking are employed to guarantee no information leakage can occur in annotated agent interaction models. The proposed security type system is discussed and then formally evaluated by proving its properties. Two disadvantages of the pure dynamic analysis are its late detection and its inability to detect implicit information flows. We overcome these issues by performing static analysis. The proposed security type system supports non-interference, i.e. high-security input to the program never affect low-security output. However, it disregards information leaks due to the termination of the program.

Prevalence and Genotype Analysis of Newborn α-Thalassemia in Wuhan Area of China

To investigate the genotypes of newborn α-thalassemia and to analyze its characteristics of molecular epidemiology in Wuhan area. The newborn α-thalassemia gene in 1376 cases with positive confirmed in the primary screening in Wuhan area was detected by PCR, flow cytometry and FISH. The α-thalassemia in 436 newborns and α- β-composite thalassemia in 10 newborns were confirmed by detection in Wuhan area. The majority of thalassemia cases [up to 92.20% (402/436)] were found to be minor and static type thalassemia including 237 cases of -SEAαα (54.36%), 135 cases of -α3.7 / αα (30.96%) and 30 case of -α4.2/αα (6.88%), however, the intermediate type -α3.7/-SEA was found in 1 newborn. The -SEA/detetion, -α3.7/detetion and -α4.2/detetion were major in the detetion, the frequency was 54.12%, 32.29% and 7.13%, respectively; while the αCS mutation, αQS mutation and αWS mutation were less in the mutation, their frequency was 3.7%, 2.45% and 0.22% respectively. The minor and static type newborn thalassemia is most common, the incidence of detetion type -SEA/αα, -α3.7/αα and α4.2/αα is more high in Wuhan area of china.

Fluorescent component and complexation mechanism of extracellular polymeric substances during dye wastewater biotreatment by anaerobic granular sludge.

In this study, methylene blue (MB) wastewater was biotreated by anaerobic granular sludge (AnGS), and the fluorescent components of extracellular polymeric substances (EPS) and complexation mechanism were evaluated. Based on the experimental data, the sorption of MB by both live and inactivated AnGS followed the pseudo-second-order model, and the adsorption isotherm conformed well to the Langmuir model. It was shown that the difference in the sorption of live and inactivated AnGS was not significant, indicating that the sorption is mainly a physical–chemical process and metabolically mediated diffusion is negligible. The interaction between EPS and MB was proved by three-dimensional excitation–emission matrix (3D-EEM) and synchronous fluorescence spectra. 3D-EEM indicated that protein (PN)-like substances were the main peaks of EPS, and gradually quenched with increase of MB concentrations. According to synchronous fluorescence spectra, the main fluorescence quenching was caused by PN-like and humic-like fractions, and belonged to the static type of quenching. FTIR spectra demonstrated that hydroxyl and amino groups played a major role in MB sorption.

Unifying nominal and structural typing

In this article, I argue for a typing scheme for modeling that unifies the hitherto separated approaches of nominal and structural typing. Both these approaches have their respective advantages and disadvantages, and I suggest a unifying approach that provides one with the best of both worlds on demand. The ultimate goal is to make a contribution toward removing the gulf currently running through the modeling community that is created by the differences between explanatory and constructive modeling with their dependence on structural and nominal typing, respectively. To this end, I first characterize the typing disciplines underlying these different schools of thought, then identify their respective trade-offs, subsequently observe what aspects of these rather different typing approaches are compatible with each other and which are inherently incompatible, and finally propose a scheme that supports fluid transitioning between the approaches.

Epidemiological aspects of healthcare-associated infections and microbial genomics.

Hospital-acquired infections (HAIs) are a cause of continuously increasing morbidity and mortality. Most of these infections are caused by a limited set of bacterial species, which share the capability to efficiently spread from patient to patient and to easily acquire antibiotic resistance determinants. This renders correct and rapid species identification and antibiotic susceptibility testing (AST) important and underscores the relevance of bacterial epidemiological typing. The latter is needed for the sensitive detection and exact tracing of nosocomial spread of these potentially multidrug-resistant microorganisms (MDRO). Many microbial typing technologies have been developed and put to some level of executive practice, but it seems that the continued evolution in methodology has currently reached an apex: there is likely to be scientific and practical consensus on the ultimate typing potential of bacterial whole-genome sequencing (WGS). The possibility to perform pan-genomic nucleotide-to-nucleotide comparisons between strains belonging to a single species and to detect even minute changes in nucleotide order will identify closely related organisms, while upon accumulation of such mutations, independent descend can be assumed. Calibration of difference levels [i.e. number of single nucleotide polymorphisms (SNPs)] into categories of inter-strain relatedness needs to be performed in order to generate robust, portable typing schemes. Here, we will briefly discuss the state of affairs regarding bacterial epidemiology based upon WGS, its relatedness with the nomenclature of former typing approaches and the continuing need for a global typing language.

The Functions of Language in Shaping Tourism Information

Providing tourists with sufficient information is one of the most crucial tasks to tourism operators. One way of achieving the goal is by means of language. This paper thus aims to discuss the functions of language in shaping various types of information to cater tourists’ diverse needs. In this study, a survey and interview were conducted to gauge the types of information which tourists perceive important and, in addition, text analysis was carried out on tourism brochures, websites and tourist information boards to grasp the functions of language in realising such messages. A total of 155 questionnaires with Cronbach’s alpha of 0.876 was used for the data analysis and the findings show that the most important information needed is on security and safety followed by attractive and appealing destinations, available facilities and public transportation. In addition, the important information on tourism commodities that tourists need is about Malaysian people in general which includes cultures and history. Similarly, the findings of text analysis highlight that the language use in tourism promotional materials is geared towards foregrounding those types of information. However, not all types of information needed by tourists are given equal attention.

ОСОБЛИВОСТІ ДАВНЬОГРЕЦЬКИХ ФРАЗЕОЛОГІЗМІВ ІЗ КОМПОНЕНТОМ-ДЕНДРОНІМОМ

The article represents the results of ancient Greek proverbs’ with dendronym component peculiarities research (with tree species name, name of a part or a fruit of a tree and their derivates). On the basis of their linguocultural and semantic analysis the characteristics of their inner form were described. On this ground an assertion was made that dendronym FIG TREE has the greatest potential for proverb forming in ancient Greek language. The existence of different lexemes in ancient Greek language for certain types and parts of this tree designation attests the wide extent of this tree and its parts usage in everyday life of Hellenes. The proverbs containing dendronym OAK are also quite numerous, while dendronyms APPLE TREE, OLIVE TREE, MYRTLE TREE, LAUREL, MULBERRY TREE, PINE TREE, MASTIK TREE, THORN TREE, POMEGRANATE TREE, CORK TREE and PEAR TREE are used much less often. Such quantitative asymmetry is caused by the peculiarities of their everyday usage by Hellenes. The largest group consists of FU, in which the specific name of the tree (and not part of the tree or fruit) is used. The study of inner form of ancient Greek FU with the dendronym component allowed to determine the cognitive mechanisms of the secondary meaning formation. 62 % FU are formed on the basis of metaphorization (on models “specific → abstract”, “plant → human”, “plant → object”, “object → object”). An equally large group consists of proverbs with a dendronym component, based on metaftonimy, a complex cognitive mechanism of metaphor and metonymy combination (the type “metonymy within metaphor” is much more productive than the type “metaphor within metonymy”). The least numerous are FU formed on the basis of metonymy. The analysis of semantics of ancient Greek FU with the dendronym component made it possible to distinguish the following types of FU motivational basis: the physical characteristics of trees, their parts and fruits, associated with the experience of their practical usage; the practice of using trees, their parts and fruits in various rituals and customs; a historical event in which a certain tree or its part was involved; characteristics of tree parts and fruits concerning their consumption as food; the mention of trees in myths and legends.

Observations Concerning the Mass Variation in a Galilean - Type Relativity

By an electric charge model of static type, with spherical distribution of field quanta, periodically emitted, and by the Galilean relativity, there are re-obtained the Lorentz’s expressions of the speed-depending longitudinal and transversal mass of a charged particle accelerated by a quanta flux pressure, as apparent effect generated by a real decreasing of the values of longitudinal and transversal electric field, EL ~ g-3; ET ~ g-1, (·g = 1/O(1 –v2/c2), being re-obtained also the general form of the Doppler-Fizeau effect. The invariance of the Lorentz force expression indicates a relativist variation of the magnetic field induction, in the form: B ~g-1, which explains the experimental result of the Kaufmann-Bucherer experiments. It is proposed a classical expression of mass and charge variation, in the form: m = mo/a; q = qo/a, (a = (1 – v2/2c2)), which may results as real variation by a significant density of a super-fluid medium of the quantum vacuum containing etherons (mg,s = 10-60¸10-70kg) and quantons (mh = h·1/c2= 7.37x10-51kg), by an relativist etherono-quantonic vortex Gr (v) which is added to the similar vortex Gm (v) of the particle’s magnetic moment which is increased with the speed, if the particle’s spin is rectangular to its impulse. The explicative model may explain also the photon’s energy in correlation with its electromagnetic properties.

Dynamic witnesses for static type errors (or, Ill-Typed Programs Usually Go Wrong)

AbstractStatic type errors are a common stumbling block for newcomers to typed functional languages. We present a dynamic approach to explaining type errors by generating counterexample witness inputs that illustrate how an ill-typed program goes wrong. First, given an ill-typed function, we symbolically execute the body to synthesize witness values that make the program go wrong. We prove that our procedure synthesizes general witnesses in that if a witness is found, then for all inhabited input types, there exist values that can make the function go wrong. Second, we show how to extend this procedure to produce a reduction graph that can be used to interactively visualize and debug witness executions. Third, we evaluate the coverage of our approach on two data sets comprising over 4,500 ill-typed student programs. Our technique is able to generate witnesses for around 85% of the programs, our reduction graph yields small counterexamples for over 80% of the witnesses, and a simple heuristic allows us to use witnesses to locate the source of type errors with around 70% accuracy. Finally, we evaluate whether our witnesses help students understand and fix type errors, and find that students presented with our witnesses show a greater understanding of type errors than those presented with a standard error message.

Migrating gradual types

Gradual typing allows programs to enjoy the benefits of both static typing and dynamic typing. While it is often desirable to migrate a program from more dynamically-typed to more statically-typed or vice versa, gradual typing itself does not provide a way to facilitate this migration. This places the burden on programmers who have to manually add or remove type annotations. Besides the general challenge of adding type annotations to dynamically typed code, there are subtle interactions between these annotations in gradually typed code that exacerbate the situation. For example, to migrate a program to be as static as possible, in general, all possible combinations of adding or removing type annotations from parameters must be tried out and compared. In this paper, we address this problem by developing migrational typing, which efficiently types all possible ways of adding or removing type annotations from a gradually typed program. The typing result supports automatically migrating a program to be as static as possible, or introducing the least number of dynamic types necessary to remove a type error. The approach can be extended to support user-defined criteria about which annotations to modify. We have implemented migrational typing and evaluated it on large programs. The results show that migrational typing scales linearly with the size of the program and takes only 2–4 times longer than plain gradual typing.

Unifying analytic and statically-typed quasiquotes

Metaprograms are programs that manipulate (generate, analyze and evaluate) other programs. These tasks are greatly facilitated by quasiquotation, a technique to construct and deconstruct program fragments using quoted code templates expressed in the syntax of the manipulated language. We argue that two main flavors of quasiquotes have existed so far: Lisp-style quasiquotes, which can both construct and deconstruct programs but may produce code that contains type mismatches and unbound variables; and MetaML-style quasiquotes, which rely on static typing to prevent these errors, but can only construct programs. In this paper, we show how to combine the advantages of both flavors into a unified framework: we allow the construction, deconstruction and evaluation of program fragments while ensuring that generated programs are well-typed and well-scoped, a combination unseen in previous work. We formalize our approach as λ {} , a multi-stage calculus with code pattern matching and rewriting, and prove its type safety. We also present its realization in Squid, a metaprogramming framework for Scala, leveraging Scala’s expressive type system. To demonstrate the usefulness of our approach, we introduce speculative rewrite rules , a novel code transformation technique that makes decisive use of these capabilities, and we outline how it simplifies the design of some crucial query compiler optimizations.

Typechecking protocols with Mungo and StMungo: A session type toolchain for Java

Static typechecking is an important feature of many standard programming languages. However, static typing focuses on data rather than communication, and therefore does not help programmers correctly implement communication protocols in distributed systems. The theory of session types provides a basis for tackling this problem; we use it to develop two tools that support static typechecking of communication protocols in Java. The first tool, Mungo, extends Java with typestate definitions, which allow classes to be associated with state machines defining permitted sequences of method calls: for example, communication methods. The second tool, StMungo, takes a session type describing a communication protocol, and generates a typestate specification of the permitted sequences of messages in the protocol. Protocol implementations can be validated by Mungo against their typestate definitions and then compiled with a standard Java compiler. The result is a toolchain for static typechecking of communication protocols in Java. We formalise and prove soundness of the typestate inference system used by Mungo, and show that our toolchain can be used to typecheck a client for the standard Simple Mail Transfer Protocol (SMTP).

To reveal the nature of interactions of human hemoglobin with gold nanoparticles having two different morphologies (sphere and star-shaped) by using various spectroscopic techniques

The nature of interactions between heme protein human hemoglobin (HHb) and gold nanoparticles of two different morphologies that is GNP (spherical) and GNS (star-shaped) have been investigated by using UV–vis absorption, steady state fluorescence, synchronous fluorescence, resonance light scattering (RLS), time resolved fluorescence, FT-IR, and circular dichroism (CD) techniques under physiological condition of pH ~7 at ambient and different temperatures. Analysis of the steady state fluorescence quenching of HHb in aqueous solution in the presence of GNP and GNS suggests that the nature of the quenching is of static type. The static nature of the quenching is also confirmed from time resolved data. The static type of quenching also indicates the possibility of formation of ground state complex for both HHb-GNP and HHb-GNS systems. From the measurements of Stern-Volmer (SV) constants KSV and binding constants, KA and number of binding sites it appears that HHb forms stronger binding with GNP relative to GNS. Analysis of the thermodynamic parameters indicates that the formation of HHb-GNP and HHb-GNS complexes are spontaneous molecular interaction processes (∆G<0). In both cases hydrogen bonding and van der Waals interactions play a dominant role (∆H<0, ∆S<0). Synchronous fluorescence spectroscopy further reveals that the ground state complex formations of HHb-GNP and HHb-GNS preferably occur by binding with the amino acid tyrosine through hydrogen bonding interactions. Moreover the α-helicity contents of the proteins as obtained from the circular dichroism (CD) spectra appears to be marginally reduced by increasing concentrations of GNP and GNS and the α-helical structures of HHb retain its identity as native secondary structure in spite of complex formations with GNP or GNS. These findings demonstrate the efficiency of biomedical applications of GNP and GNS nanoparticles as well as in elucidating their mechanisms of action as drugs or drug delivery systems in human.

Mining inline cache data to order inferred types in dynamic languages

The lack of static type information in dynamically-typed languages often poses obstacles for developers. Type inference algorithms can help, but inferring precise type information requires complex algorithms that are often slow. A simple approach that considers only the locally used interface of variables can identify potential classes for variables, but popular interfaces can generate a large number of false positives. We propose an approach called inline-cache type inference (ICTI) to augment the precision of fast and simple type inference algorithms. ICTI uses type information available in the inline caches during multiple software runs, to provide a ranked list of possible classes that most likely represent a variable's type. We evaluate ICTI through a proof-of-concept that we implement in Pharo Smalltalk. The analysis of the top-n+2 inferred types (where n is the number of recorded run-time types for a variable) for 5486 variables from four different software systems shows that ICTI produces promising results for about 75% of the variables. For more than 90% of variables, the correct run-time type is present among first six inferred types. Our ordering shows a twofold improvement when compared with the unordered basic approach, i.e., for a significant number of variables for which the basic approach offered ambiguous results, ICTI was able to promote the correct type to the top of the list.

Biophysical and In Silico Studies of the Interaction between the Anti-Viral Agents Acyclovir and Penciclovir, and Human Serum Albumin.

Acyclovir (ACV) and penciclovir (PNV) have been commonly used during the last few decades as potent antiviral agents, especially for the treatment of herpes virus infections. In the present research their binding properties with human serum albumin (HSA) were studied using different advanced spectroscopic and in-silico methods. The interactions between ACV/PNV and HSA at the three investigated temperatures revealed a static type of binding. Extraction of the thermodynamic parameters of the ACV-HSA and PNV-HSA systems from the measured spectrofluorimetric data demonstrated spontaneous interactions with an enthalpy change (∆H0) of −1.79 ± 0.29 and −4.47 ± 0.51 kJ·mol−1 for ACV and PNV, respectively. The entropy change (∆S0) of 79.40 ± 0.95 and 69.95 ± 1.69 J·mol−1·K−1 for ACV and PNV, respectively, hence supported a potential contribution of electrostatic binding forces to the ACV-HSA and PNV-HSA systems. Putative binding of ACV/PNV to HSA, using previously reported site markers, showed that ACV/PNV were bound to HSA within subdomains IIA and IIIA (Sudlow sites I and II). Further confirmation was obtained through molecular docking studies of ACV-HSA and PNV-HSA binding, which confirmed the binding site of ACV/PNV with the most stable configurations of ACV/PNV within the HSA. These ACV/PNV conformers were shown to have free energies of −25.61 and −22.01 kJ·mol−1 for ACV within the HSA sites I and II and −22.97 and −26.53 kJ·mol−1 for PNV in HSA sites I and II, with hydrogen bonding and electrostatic forces being the main binding forces in such conformers.

Organometallic ruthenium(II) complexes containing NS donor Schiff bases: Synthesis, structure, electrochemistry, DNA/BSA binding, DNA cleavage, radical scavenging and antibacterial activities

Four new cyclopentadienylruthenium(II)-acetophenone-4(N)-substituted thiosemi-carbazone complexes, with the general formula [Ru(ƞ5-C5H5)(H-Aptsc)PPh3].Cl (1), [Ru(ƞ5-C5H5)(H-Apmtsc)PPh3].Cl (2), [Ru(ƞ5-C5H5)(H-Ap-etsc)PPh3].Cl (3) and [Ru(ƞ5-C5H5)(H-Ap-ptsc)PPh3].Cl (4) were synthesised and characterised (1H NMR, 13C NMR, IR and electronic spectroscopy). The molecular structure of representative complexes 2 and 3 was confirmed by single crystal X-Ray diffraction technique. The binding ability of complexes (1–4) to calf-thymus DNA (CT DNA) and Bovine Serum Albumin (BSA) has been explored by absorption and emission titration methods. Based on the observations, an electrostatic and an intercalative binding mode have been proposed for the complexes with CT-DNA. The BSA protein binding studies have been monitored by quenching of tryptophan and tyrosine residues in the presence of complexes and static type of quenching mechanism has been proposed. In vitro free radical scavenging activity was performed by DPPH radical. The complexes (1–4) exhibited highest scavenging activity than conventional standard vitamin C (IC50 = 5.65 ± 0.12). Further, antibacterial activity of the complexes has been screened against four pathogenic bacteria such as Salmonella paratyphi, Staphylococcus aureus, Escherichia coli and Bacillus subtilis. From the results it is found that all the complexes exhibited significant activity against the pathogens and among them, complex 3 exhibited higher activity.

Challenges and progress toward efficient gradual typing (invited talk)

Mixing static and dynamic type checking in the same language is catching on, with the TypeScript and Flow variants of JavaScript, the MyPy and Reticulated variants of Python, the Strongtalk and Gradualtalk variants of Smalltalk, as well as Typed Racket, Typed Clojure, and Perl 6. The gradual typing approach to such mixing seeks to protect the statically typed code from the dynamically typed code, allowing compilers to leverage type information when optimizing the static code. Unfortunately, ensuring soundness requires runtime checking at the boundaries of typed and untyped code, and the cost of this checking can drown out the performance benefits of optimization. For example, in Typed Racket, some partially typed programs are 1000X slower than the untyped or fully typed version of the same program. But all is not lost! In this talk I present the results of ongoing research to tame the runtime overheads of gradual typing in the context of a prototype compiler, named Grift, that we are developing at Indiana University.

Theoretical transient analysis of a hearing aid feedback canceller with a saturation type nonlinearity in the direct path

Feedback cancellation in a hearing aid is essential for achieving high maximum stable gain to compensate for the losses in severe to profound hearing impaired people. The performance of adaptive feedback cancellers has been studied by assuming that the feedback path can be modeled as a linear system. However, limited dynamic range, low-cost loudspeakers, and nonlinear power amplifiers may distort the hearing aid output signal. In this way, linear-based predictions of the canceller performance may lead to significant deviations from its actual behavior. This work presents a theoretical performance analysis of a Least Mean Square based shadow filter that is applied to set up the coefficients of a feedback canceller, which is subject to a static saturation type nonlinearity at the output of the direct path. Deterministic recursive equations are derived to predict the mean square feedback error and the mean coefficient vector evolution between updates of the feedback canceller. These models are defined as functions of the canceller parameters and input signal statistics. Comparisons with Monte Carlo simulations show the provided models are highly accurate under the considered assumptions. The developed models allow inferences about the potential impact of an overdriven loudspeaker over the transient performance of the direct method feedback canceller, serving as insightful tools for understanding the involved mechanisms.