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Acute pyogenic meningitis is a medical emergency. Bacteria are the major causative agents of pyogenic meningitis with Streptococcus pneumoniae, Haemophilus influenzae,and Neisseria meningitidisbeing the most common. Here, we describe a case of bacterial meningoencephalitis caused by Streptococcus porcinus. To our knowledge this is the first case described in literature. The patient was treated with ceftriaxone and supportive treatment.

Hierarchical information networks are important in applications where the information management must support an existing tree-structured organization. Embedded computer-communication systems in military applications, with a dominant hierarchical command structure, are the most prominent examples. Also typical of such applications is the variability in message demand (both sources and intensity) depending on the external conditions encountered by the encapsulating system (the system supported by the embedded computer-communication system). Using a queueing network model for a hierarchical information network, we compare the effect of limited dynamic reconfiguration on expected transmission delays. The limited reconfigurability takes the form of apex transition among a proper subset of the communication nodes designated as the apex candidate set. Each apex candidate can assume the ultimate position under designated conditions. This network architecture is called a dynamic hierarchy.The model includes N +1 nodes (0, …, N) with 0 identifying the apex node. We assume that message processing at each node is described by an M/M/1 model (single server with Poisson arrivals and exponential service times). Further message transfers among the nodes are served by communication links which also behave as M/M/1 queues.Two distinctive features characterize the queueing network model:1. The assignment of a set of weights to the nodes dependent on the hierarchical level reflects the increasing importance of information as it is transferred to higher levels.2. The dynamic hierarchy requires a communications protocol that partitions the analysis of network delay into three periods: regular operation, reconfiguration, and adjustment. Characterization of the performance of the dynamic hierarchy entails the description of message transmission delay as a composite of the three periods.

The structures of high molecular weight sulfated oligosaccharide chains in mucins purified from the sputum of a patient with cystic fibrosis and blood group H determinant were established. Reduced oligosaccharides released by treatment with alkaline borohydride were separated by ion exchange chromatography on DEAE-Agarose and a fraction containing multisulfated chains was further purified by lectin affinity chromatography to completely remove small amounts of sialylated chains. A major sulfated oligosaccharide fraction containing chains with an average of 160 to 200 sugar residues was isolated by gel filtration on BioGel P-10 columns and individual subfractions were characterized by methylation analysis, periodate oxidation and sequential glycosidase digestion before and after desulfation. Carbohydrate analysis yielded Fuc, Gal and GldNAc in a ratio of 1:2:2.1 and only one galactosaminitol residue for every 160-to 200 sugar residues. The average molecular weight of oligosaccharide chains in these fractions was between 27,000 and 40,000 daltons. Structural analysis showed that these high molecular weight chains contained varying amounts of the repeating unit shown in the following oligosaccharide. Only one in about every 10 repeating units contained sulfate esters.

A reduced system is a smaller system derived in the process of analyzing a larger system. While solving for steady-state probabilities of a Markov chain, generally the solution can be found by first solving a reduced system of equations which is obtained by appropriately partitioning the transition probability matrix. In this paper, we catagorize reduced systems as standard and nonstandard and explore the existence of reduced systems and their properties relative to the original system. We also discuss first passage probabilities and means for the standard reduced system relative to the original system. These properties are illustrated while determining the steady-state probabilities and first passage time characteristics of a queueing system.

Maximum likelihood estimators for the parameters of a GI/G/1 queue are derived based on the information on waiting times {Wt},t=1,...,n, ofnsuccessive customers. The consistency and asymptotic normality of the estimators are established. A simulation study of the M/M/1 and M/Ek/1 queues is presented.

This paper provides an overview of the literature on statistical analysis of queueing systems. Topics discussed include: model identification, estimation, hypothesis testing and other related aspects. Not all of these statistical problems are covered in books on queueing theory or stochastic processes. The bibliography is not exhaustive, but comprehensive enough to provide sources from the literature.

In assembly lines, service involves assembling units coming from more than one source. In queue terminology, we may consider this situation as one in which service is rendered only to groups of customers — one from each class. In this paper we give procedures to determine response time characteristics of such a system under Markovian assumptions when a finite capacity restriction is imposed. This restriction is imposed to reflect reality as well as to make analysis tractable. In the course of this study, we also give a recursive technique to determine the distribution of the time taken for a specific number of departures in a Poisson queue from an arbitrary initial state. We demonstrate that this distribution is related to the response time distribution of the assembly-like queue. We believe that this procedure will also be of independent interest.

In view of the enormous amount of backwater stretches which in principle could be potential aquaculture grounds in tropical coastal India, there has been a growing interest to map suitable locations for brackish-water fish culture. The interest has also grown stronger in the recent days with the launch of India's own remote sensing satellite which has capabilities on par with Landsat. This attempt envisages to explain remote sensing methods of mapping coastal aquaculture areas using the inexpensive data of Indian Remote Sensing satellite - IRS-1 A.

Markov trials are a sequence of dependent trials with two outcomes, success and failure, which are the states of a Markov chain. The distribution of the number of successes in nMarkov trials and the first-passage time for a specified number of successes are obtained using an augmented Markov chain model.

Summary The queue length process in a queue with limited waiting room capacity can be said to go through two types of periods viz., ‘customer-loss period’ and ‘no-loss period’. For the queueing systems M/G/1 and GI/M/1, a study has been made in this paper, of the imbedded Markov chains of the queue length process with regard to the transitions in a ‘no-loss period’.

We previously showed that there is a structure-function relationship among reserpine and yohimbine analogues in their ability to inhibit the function of P-glycoprotein (P-gp) and reverse multidrug resistance (MDR). Because some P-gp inhibitors (e.g., verapamil and nifedipine) can increase mdr1 and P-gp expression in human colon carcinoma cell lines, we used our reserpine/yohimbine analogues to determine whether there was a structural requirement for this induction. We found that 10 microM reserpine increased both mdr1 and P-gp expression by 4-10-fold in 48 hr in a human colon carcinoma cell line that expresses moderate levels of mdr1 (LS180-Ad50) but not in several other cell lines that expressed no mdr1. The reserpine/yohimbine analogues rescinnamine, trimethoxybenzoylyohimbine, and LY191401 (compound G), all of which contain the three structural elements used to describe the MDR pharmacophore, also increased both mdr1 and P-gp expression significantly. Despite some exceptions, we found that there was a good association between the ability of these analogues to induce mdr1 and P-gp expression and their ability to reverse vinblastine and doxorubicin resistance, revealing a structure-function relationship for this phenomenon. The increased P-gp expressed by these cells appeared to be functional, as determined by flow cytometric detection of rhodamine 123 retention. The increased expression was suppressed by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, an RNA synthesis inhibitor, whereas the protein synthesis inhibitor cycloheximide enhanced the expression several-fold, suggesting that induction of mdr1 by these analogues is regulated at both the transcriptional and post-transcriptional levels.(ABSTRACT TRUNCATED AT 250 WORDS)

An M/Ez/1 queue (i.e. a single-server queue having a Poisson arrival process and weighted-sum Erlangian service) can approximate a wide range of queueing systems quite closely. For this system a practical computational scheme is developed for determining (1) the expected amount of time the server is idle in the interval (0, t] and (2) the expected waiting time of a customer arriving at time t. The initial service load can be specified arbitrarily. Sample results and computer time requirements are also discussed.

A random walk describes the movement of a particle in discrete time, with the direction and the distance traversed in one step being governed by a probability distribution. In a correlated random walk (CRW) the movement follows a Markov chain and induces correlation in the state of the walk at various epochs. Then, the walk can be modelled as a bivariate Markov chain with the location of the particle and the direction of movement as the two variables. In such random walks, normally, the particle is not allowed to stay at one location from one step to the next. In this paper we derive explicit results for the following characteristics of the CRW when it is allowed to stay at the same location, directly from its transition probability matrix: (i) equilibrium solution and the fast passage probabilities for the CRW restricted on one side, and (ii) equilibrium solution and first passage characteristics for the CRW restricted on bath sides (i.e., with finite state space).

Amylolysis of chemically ‐ treated starch granules of black gram and ragi was followed colorimetrically and by scanning electron microscopy. From the percent hydrolysis values it was evident that oxidation with periodate resulted in considerable resistance, whereas urea treatment resulted in granule susceptibility towards in vitroamylolysis. The action of α‐amylase and/or glucoamylase on periodate oxidised black gram starch showed on SEM sufficient enlargement of the granules and hollow craters as well; whereas similar treatment on oxidised ragi starch resulted in folded, distorted and deformed granules. Treatment with 8M urea resulted in the total loss of characteristic granular shape and formation of the socalled amylopectin “sacs”. Like waxy starches the latter showed an increase in enzymic activity. Particularly, the synergistic action of α‐amylase and glucoamylase on ureatreated starches virtually collapsed the granules, forming innumerable “flat” ribbon like fragments. Raster‐Elektronenmikroskopie von chemisch und enzymatisch behandelten Black Gram‐ (Phaseolus mungo) und Ragi‐(Eleusine coracana) Stärkekörnern.Die Amylolyse von chemisch behandelten Stärkekörnern von Black Gram und Ragi wurde kolorimetrisch und durch Raster‐Elektronenmikroskopie (SEM) verfolgt. Aus den prozentualen Hydrolysewerten wurde deutlich, daß die Perjodatoxidation beträchtlichen Widerstand hervorrief, wogegen eine Harnstoffbehandlung beim Korn eine Suszeptibilität gegenüber der in vitro‐Amylose bewirkte. Die Wirkung von α‐Amylase und/oder Glucoamylase auf perjodatoxidierte Black Gram‐Stärke zeigte bei der SEM ausreichende Vergrößerung der Körner ebenso wie Hohlkrater. Demgegenüber führte die ähnliche Behandlung oxidierter Ragi‐Stärke zu gefalteten, verzogenen und deformierten Körnern. Die Behandlung mit 8‐M Harnstoff resultierte in dem vollständigen Verlust der charakteristischen Korngestalt und in der Bildung sogenannter Amylopektin‐„Säcke”︁. Ähnlich wie wachsige Stärken zeigten letztere eine Zunahme der enzymatischen Aktivität. Besonders die synergistische Wirkung von α‐Amylase und Glucoamylase auf harnstoffbehandelte Stärken ließ die Körner unter Bildung unzähliger flacher bandartiger Fragmente vollständig zusammenfallen.

Lipopolysaccharide (LPS) was isolated from free-living Rhizobium leguminosarum bv. phaseoli CE3 cells grown at pH 4.8 (antigenically similar to bacteroid LPS) and compared with that from cells grown at pH 7.2 (free-living bacteria). Composition analysis revealed that pH 7.2 LPS differs from pH 4.8 LPS in that 2,3,4-tri-O-methylfucose is replaced by 2,3-di-O-methylfucose. The amount of 2-O-methylrhamnose is greater in the pH 4.8 LPS than in the pH 7.2 LPS. Analysis of the structural components of LPS (O-chain polysaccharide, core oligosaccharides, and the lipid A) revealed that all the composition differences in the various LPSs occur in the O-chain polysaccharide. These structural variations between pH 4.8 and pH 7.2 LPSs provide a chemical basis for the observed lack of cross-reactivity with pH 4.8 LPS of two monoclonal antibodies, JIM28 and JIM29, raised against free-living bacteria grown at pH 7.2. An LPS preparation isolated from bacteroids contained both 2,3,4-tri-O- and 2,3-di-O-methylfucose residues. This result is consistent with the finding that the two monoclonal antibodies react weakly with bacteroid LPS. It is concluded that methylation changes occur on the LPS O-chain of R. leguminosarum bv. phaseoli when the bacteria are grown at low pH and during nodule development.

Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane, and for Rhizobiumspp. has been shown to play a critical role in the establishment of an effective nitrogen-fixing symbiosis with a legume host. Many genes required for O-chain polysaccharide synthesis are in the lpsα region of the CE3 genome; this region may also carry lpsgenes required for core oligosaccharide synthesis. The LPSs from several strains mutated in the α region were isolated, and their mild acid released oligosaccharides, purified by high performance anion-exchange chromatography, were characterized by electrospray- and fast atom bombardment-mass spectrometry, NMR, and methylation analysis. The LPSs from several mutants contained truncated O-chains, and the core region consisted of a (3-deoxy-D-manno-2-octulosomic acid) (Kdo)-(2→6)-α-Galp-(1→6)-[α-GalpA-(1→4)]-α-Manp-(1→5)-Kdop(3-deoxy-D-manno-2-octulosomic acid) (Kdo)pentasaccharide and a α-GalpA-(1→4)-[α-GalpA-(1→5)]-Kdoptrisaccharide. The pentasaccharide was altered in two mutants in that it was missing either the terminal Kdo or the GalA residue. These results indicate that the lpsα region, in addition to having the genes for O-chain synthesis, contains genes required for the transfer of these 2 residues to the core region. Also, the results show that an LPS with a complete core but lacking an O-chain polysaccharide is not sufficient for an effective symbiosis.

In a correlated random walk (CRW) the probabilities of movement in the positive and negative direction are given by the transition probabilities of a Markov chain. The walk can be represented as a Markov chain if we use a bivariate state space, with the location of the particle and the direction of movement as the two variables. In this paper we derive explicit results for the following characteristics of the walk directly from its transition probability matrix: (i) n-step transition probabilities for the unrestricted CRW, (ii) equilibrium distribution for the CRW restricted on one side, and (iii) equilibrium distribution and first-passage characteristics for the CRW restricted on both sides (i.e., with finite state space).

Maximum likelihood estimators of the parameters of an open Jackson network are derived, and their joint asymptotic normality is established. The problem of estimation for tandem queues is discussed as a special case of the Jackson system. These results are valid when the system is not necessarily in equilibrium.

The reliability of a system is the probability that the system will perform its intended mission under given conditions. This paper provides an overview of the approaches to reliability modelling and identifies their strengths and weaknesses. The models discussed include structure models, simple stochastic models and decomposable stochastic models. Ignoring time-dependence, structure models give reliability as a function of the topological structure of the system. Simple stochastic models make direct use of the properties of underlying stochastic processes, while decomposable models consider more complex systems and analyse them through subsystems. Petri nets and dataflow graphs facilitate the analysis of complex systems by providing a convenient framework for reliability analysis.

Lipopolysaccharide (LPS) is a major component of the bacterial outer membrane, and for Rhizobium spp. has been shown to play a critical role in the establishment of an effective nitrogen-fixing symbiosis with a legume host. Many genes required for O-chain polysaccharide synthesis are in the lps alpha region of the CE3 genome; this region may also carry lps genes required for core oligosaccharide synthesis. The LPSs from several strains mutated in the alpha region were isolated, and their mild acid released oligosaccharides, purified by high performance anion-exchange chromatography, were characterized by electrospray- and fast atom bombardment-mass spectrometry, NMR, and methylation analysis. The LPSs from several mutants contained truncated O-chains, and the core region consisted of a (3-deoxy-D-manno-2-octulosomic acid) (Kdo)-(2-->6)-alpha-Galp-(1-->6)-[alpha-GalpA-(1-->4)]-alpha-Ma np-(1-->5)- Kdop (3-deoxy-D-manno-2-octulosomic acid) (Kdo)pentasaccharide and a alpha-GalpA-(1-->4)-[alpha-GalpA-(1-->5)]-Kdop trisaccharide. The pentasaccharide was altered in two mutants in that it was missing either the terminal Kdo or the GalA residue. These results indicate that the lps alpha region, in addition to having the genes for O-chain synthesis, contains genes required for the transfer of these 2 residues to the core region. Also, the results show that an LPS with a complete core but lacking an O-chain polysaccharide is not sufficient for an effective symbiosis.

Lipopolysaccharides (LPSs) isolated from several strains of Rhizobium, Bradyrhizobium, Agrobacterium, and Azorhizobium were screened for the presence of 27-hydroxyoctacosanoic acid. The LPSs from all strains, with the exception of Azorhizobium caulinodans, contained various amounts of this long-chain hydroxy fatty acid in the lipid A fractions. Analysis of the lipid A sugars revealed three types of backbones: those containing glucosamine (as found in Rhizobium meliloti and Rhizobium fredii), those containing glucosamine and galacturonic acid (as found in Rhizobium leguminosarum bv. phaseoli, trifolii, and viciae), and those containing 2,3-diamino-2,3-dideoxyglucose either alone or in combination with glucosamine (as found in Bradyrhizobium japonicum and Bradyrhizobium sp. [Lupinus] strain DSM 30140). The distribution of 27-hydroxyoctacosanoic acid as well as analysis of lipid A backbone sugars revealed the taxonomic relatedness of various strains of the Rhizobiaceae.

The lipopolysaccharide (LPS) of Bradyrhizobium japonicum 61A123 was isolated and partially characterized. Phenol-water extraction of strain 61A123 yielded LPS exclusively in the phenol phase. The water phase contained low-molecular-weight glucans and extracellular or capsular polysaccharides. The LPSs from B. japonicum 61A76, 61A135, and 61A101C were also extracted exclusively into the phenol phase. The LPSs from strain USDA 110 and its Nod- mutant HS123 were found in both the phenol and water phases. The LPS from strain 61A123 was further characterized by polyacrylamide gel electrophoresis, composition analysis, and 1H and 13C nuclear magnetic resonance spectroscopy. Analysis of the LPS by polyacrylamide gel electrophoresis showed that it was present in both high- and low-molecular-weight forms (LPS I and LPS II, respectively). Composition analysis was also performed on the isolated lipid A and polysaccharide portions of the LPS, which were purified by mild acid hydrolysis and gel filtration chromatography. The major components of the polysaccharide portion were fucose, fucosamine, glucose, and mannose. The intact LPS had small amounts of 2-keto-3-deoxyoctulosonic acid. Other minor components were quinovosamine, glucosamine, 4-O-methylmannose, heptose, and 2,3-diamino-2,3-dideoxyhexose. The lipid A portion of the LPS contained 2,3-diamino-2,3-dideoxyhexose as the only sugar component. The major fatty acids were beta-hydroxymyristic, lauric, and oleic acids. A long-chain fatty acid, 27-hydroxyoctacosanoic acid, was also present in this lipid A. Separation and analysis of LPS I and LPS II indicated that glucose, mannose, 4-O-methylmannose, and small amounts of 2,2-diamino-2,3-dideozyhexose and heptose were components of the core region of the LPS, whereas fucose, fucosmine, mannose, and small amounts of quinovosamine and glucosamine were components of the LPS O-chain region.

Human respiratory mucin glycoproteins from patients with cystic fibrosis were purified and oligosaccharide chains were released by treatment with alkaline borohydride. A neutral oligosaccharide alditol fraction was isolated from mucin obtained from a patient with A blood group determinant by chromatography on DEAF-cellulose and individual oligosaccharide chains were then isolated by gel filtration on BioGel P-6 columns and high performance liquid chromatography with gradient and isocratic solvent systems. The structures of the purified oligosaccharides were determined by methylation analysis, sequential glycosidase digestion and 'H-NMR spectroscopy. The amount of each chain was determined by compositional analysis. A wide array of discrete branched oligosaccharide structures that contain from 3 to 22 sugar residues were found. Many of the oligosaccharides are related and appear to be precursors of larger chains. The predominant branched oligosaccharides which accumulate contain terminal blood group H (Fuca2Ga1ß4) or blood group A (Fuca2(Ga1NAca3) (Ga1ß4) determinants which stop further branching and chain elongation. The elongation of oligosaccharide chains in respiratory mucins occurs on the ß3-linked G1cNAc at branch points, whereas the 6-linked GlcNAc residue ultimately forms short side chains with a Fuca2 (Ga1NAca3) Galß4 G1cNAcß6 structure in individuals with A blood group determinant.

Bradyrhizobium japonicum is a soil bacterium that forms nitrogen-fixing nodules on the roots of the agronomically important legume soybean. Microscopic observation of plant roots showed that butanol extract of B. japonicum strain USDA110 cultures induced for nod gene expression elicited root hair deformation, an early event in the nodulation process. The metabolite produced by B. japonicum responsible for root hair deformation activity was purified. Chemical analysis of the compound revealed it to be a pentasaccharide of N-acetylglucosamine modified by a C18:1 fatty acyl chain at the nonreducing end. In these respects, the B. japonicum metabolite is similar to the lipo-oligosaccharide signals described from Rhizobium species. However, the B. japonicum compound is unique in that an additional sugar, 2-O-methylfucose, is linked to the reducing end. Comparative analysis of the B. japonicum Nod metabolite and those characterized from Rhizobium species suggests that the presence of the fucosyl residue plays an important role in the specificity of the B. japonicum-soybean symbiosis. The availability of the purified B. japonicum nodulation signal should greatly facilitate further studies of soybean nodulation.

SummaryIn this paper results from Fluctuation Theory are used to analyse the imbedded Markov chains of two single server bulk-queueing systems, (i)with Poisson arrivals and arbitrary service time distribution and (ii) with arbitrary inter-arrival time distribution and negative exponential service time. The discrete time transition probailities and the equilibrium behaviour of the queue lengths of the systems have been obtained along with distributions concerning the busy periods. From the general results several special cases have been derived.

The time dependent behaviour of the two server queueing system with recurrent input and negative exponential service times is studied here using certain recurrence relations for the underlying queuelength process. The service times have a varying mean depending on the number of busy servers.

SummaryCustomers arrive in a recurrent process and get served by one of the s(?1) servers wit han exponential service time distribution. The equilibrium behavior of the queue length process has been studied by earlier authors. In this paper the transient behavior of this process is investigated.

The distribution of the busy period in a single server bulk queue with Poisson arrivals and a service mechanism providing for a different distribution for the first service time in a busy period is derived and a method of obtaining the transient behaviour of the queue length process is indicated.

SummaryTransition distribution functions (d.f.) of the stochastic process u+ t- X(t), where X(t) has a compound Poisson distribution, are used to derive explicit results for the transition d.f.s of the waiting time processes in the queueing systems M/G/1 and GI/M/1.

DNA topoisomerase (topo) II inhibitors either stabilize DNA–topo II complexes by blocking DNA religation (e.g. etoposide) or block the enzyme's catalytic activity (e.g. dexrazoxane). The former class of drugs causes direct DNA damage through topo II, while the latter class does not, but both classes cause apoptosis. We cloned the Fas ligand (FasL) promoter and coupled it to the luciferase gene. Treatment of cells transfected with this construct revealed that complex-stabilizing (DNA-damaging) agents induce FasL expression, but the catalytic inhibitors do not, suggesting that the FasL pathway may not be involved in all cases of topoisomerase-mediated apoptosis. Some topo II inhibitors activate a pathway involving stress-activated protein kinases, which include c-Jun N-terminal kinase-1 (JNK-1). We will discuss the effects of these agents on components of this pathway. Our earlier work revealed that topo IIα interacts with the cell cycle regulatory protein, retinoblastoma protein (Rb). This interaction and the subcellular distribution of these proteins are altered by topo II inhibitory drugs and lead to apoptosis. In addition, agents that affect Rb, such as E1A and E2F1/DP-1, when transfected into cells, also alter topo IIα-Rb localization, activate jun kinase pathways and cause apoptosis. This paper discusses current studies that are designed to determine the contributions of these signalling events to the alterations in subcellular protein distribution and apoptosis. We suggest that protein-protein interactions are important for mediation of cytotoxic signalling by anticancer drugs.

Erythrocytic forms ofBabesia bovisinoculated into cell cultures of the tickBoophilus microplusinvaded the tick cells and showed multiplication for up to 48 h after inoculation.

Five types of haemocytes were detected in the haemolymph ofAedes albopictuslarva. Their comparison with the cells growing in the larval cell cultures of this mosquito indicated that the prohaemocytes, two types of podocytes, plasmatocytes and spherules of larval haemolymph correspond with the types A, B and C epithelial-like cells, type A fibroblast-like cells and vacuolated round cells in the culture respectively.

For Abstract see ChemInform Abstract in Full Text.

For Abstract see ChemInform Abstract in Full Text.

Highly purified lipopolysaccharides (LPS) obtained from four strains of Pasteurella haemolytica representative of four different serotypes were studied to ascertain their overall structural elements and sugar and fatty acid compositions. SDS-PAGE analysis revealed that each LPS was of the smooth-type although they differed in migration patterns. Somewhat unusual features of these LPS included the presence of: (a) rhammose in the core oligosaccharides of serotypes 2 and 3; and (b) sialic acid in the LPS of serotypes 1 and 5. The fatty acids, myristic, hydroxymyristic and palmitic occur in essentially equivalent amounts in each of these LPS. In addition, stearic acid was present in small amounts in serotypes 1 and 5.

The attempted transformation of parthenin (I) into damsin in refluxing formic acid results in formation of anhydroparthenin (II) as the major product.

A random walk describes the movement of a particle in discrete time, with the direction and the distance traversed in one step being governed by a probability distribution. In a correlated random walk (CRW) the movement follows a Markov chain and induces correlation in the state of the walk at various epochs. Then, the walk can be modelled as a bivariate Markov chain with the location of the particle and the direction of movement as the two variables. In such random walks, normally, the particle is not allowed to stay at one location from one step to the next. In this paper we derive explicit results for the following characteristics of the CRW when it is allowed to stay at the same location, directly from its transition probability matrix: (i) equilibrium solution and the fast passage probabilities for the CRW restricted on one side, and (ii) equilibrium solution and first passage characteristics for the CRW restricted on bath sides (i.e., with finite state space).

During the attempted preparation of damsin (I) from parthenin (II), an intermediate step requires the protection of the α‐methylene group of anhydroparthenin (III) by dimethylamine.