LCMS-Metabolomic Profiling and Genome Mining of Delftia lacustris DSM 21246 Revealed Lipophilic Delftibactin Metallophores.

Bacteria have evolved various strategies to combat heavy metal stress, including the secretion of small molecules, known as metallophores. These molecules hold a potential role in the mitigation of toxic metal contamination from the environment (bioremediation). Herein, we employed combined comparative metabolomic and genomic analyses to study the metallophores excreted by Delftia lacustris DSM 21246. LCMS-metabolomic analysis of this bacterium cultured under iron limitation led to a suite of lipophilic metallophores exclusively secreted in response to iron starvation. Additionally, we conducted genome sequencing of the DSM 21246 strain using nanopore sequencing technology and employed antiSMASH to mine the genome, leading to the identification of a biosynthetic gene cluster (BGC) matching the known BGC responsible for delftibactin A production. The isolated suite of amphiphilic metallophores, termed delftibactins C-F (1-4), was characterized using various chromatographic, spectroscopic, and bioinformatic techniques. The planar structure of these compounds was elucidated through 1D and 2D NMR analyses, as well as LCMS/MS-based fragmentation studies. Notably, their structures differed from previously known delftibactins due to the presence of a lipid tail. Marfey's and bioinformatic analyses were employed to determine the absolute configuration of the peptide scaffold. Delftibactin A, a previously identified metallophore, has exhibited a gold biomineralizing property; compound 1 was tested for and also demonstrated this property.

Metabolism of natural and synthetic bioactive compounds in Cunninghamella fungi and their applications in drug discovery.

Investigation of xenobiotic metabolism is a key step for drug discovery. Since the in vivo investigations may be associated with harmful effects attributed to production of toxic metabolites, it is deemed necessary to predict their structure especially at the preliminary clinical studies. Furthermore, the application of microorganisms that are capable of metabolizing drugs mimic human metabolism and consequently may predict possible metabolites. The genus Cunninghamella has been proven to be a potential candidate, which mimics xenobiotic metabolism occurring inside the human body, including phase I and II metabolic reactions. Moreover, biotransformation with Cunninghamella showed chemical diversity, where a lot of products were detected in relation to the initial substrates after being modified by oxidation, hydroxylation, and conjugation reactions. Some of these products are more bioactive than the parent compounds. The current review presents a comprehensive literature overview regarding the Cunninghamella organisms as biocatalysts, which simulate mammalian metabolism of natural secondary and synthetic compounds.

Cervical cancer screening uptake in Sub-Saharan Africa: a systematic review and meta-analysis.

OBJECTIVES: The objective of this study is to estimate the pooled uptake of cervical cancer screening and identify its predictors in Sub-Saharan Africa. STUDY DESIGN: Systematic review and meta-analysis. METHODS: We searched PubMed, EMBASE, CINAHL, African Journals OnLine, Web of Science and Scopus electronic databases from January 2000 to 2019. All observational studies published in the English language that reported cervical cancer uptake and/or predictors in Sub-Saharan Africa were initially screened. We assessed methodological quality using the Newcastle-Ottawa Scale. An inverse variance-weighted random-effects model meta-analysis was performed to estimate the pooled uptake and odds ratio (OR) of predictors with a 95% confidence interval (CI). The I2 test statistic was used to check between-study heterogeneity, and the Egger's regression statistical test was used to check publication bias. RESULTS: We initially screened 3537 citations and subsequently 29 studies were selected for this review, which included a total of 36,374 women. The uptake of cervical cancer screening in Sub-Saharan Africa was 12.87% (95% CI: 10.20, 15.54; I2 = 98.5%). A meta-analysis of seven studies showed that knowledge about cervical cancer increased screening uptake by nearly five times (OR: 4.81; 95% CI: 3.06, 7.54). Other predictors of cervical screening uptake include educational level, age, Human Immune deficiency Virus (HIV) status, contraceptive use, perceived susceptibility and awareness about screening locations. CONCLUSIONS: Cervical screening uptake is low in Sub-Saharan Africa as a result of several factors. Health outreach and promotion programmes to target these identified predictors are required.

Communication Aspects of Visible Light Positioning (VLP) Systems Using a Quadrature Angular Diversity Aperture (QADA) Receiver.

Visible light positioning (VLP) is a promising indoor localization system in which light emitting diode (LED) luminaires are used as positioning beacons. Data communication is an essential aspect of any VLP system, as each luminaire must transmit information about its own location to the receiver. The quadrature angular diversity aperture (QADA) is a new receiver designed specifically for VLP systems using angle-of-arrival estimation. Previous QADA research has focused only on positioning and assumed error-free communication. In this paper, we investigate, via simulations and experiment, the actual communication characteristics of a VLP system that uses a QADA receiver. We calculate the signal-to-noise ratio and bit-error-rates for a range of scenarios and demonstrate the impact of the dimensions of the receiver. We show that reliable communication is assured in typical operating scenarios, proving that communication will not be a limiting factor when using QADA in VLP systems.

Ethnic differences in sedentary behaviour in 6-8-year-old children during school terms and school holidays: a mixed methods study.

BACKGROUND: Sedentary behaviour (SB) in childhood is a major public health concern. Little is known about ethnic differences in SB during school and holiday weeks among White British (WB) and South Asian (SA) children, which this study aims to address through investigating inclinometer measured SB and exploring reasons for child engagement in SB. METHODS: A mixed methods study, comprising of a quantitative investigation with 160, 6-8 years old children and a qualitative study with a subsample of 18 children, six parents and eight teachers was undertaken. Children of WB and SA ethnicity in three schools were invited to wear inclinometers for seven school terms (summer/winter/spring) and seven holidays (winter/spring) days during July 2016-May 2017. Total SB, SB accumulated in bouts > 30 min and breaks in SB were explored using multivariate linear mixed effects models which adjusted for wear time, sex, deprivation, overweight status, season, term, weekday and school. Nine focus groups and two interviews were carried out using the Theoretical Domains Framework to explore SB perceptions among parents, teachers and children. Data were analysed using the Framework Approach. RESULTS: 104/160 children provided 836 valid days of data. Children spent on average eight hours of SB/day during term time and holidays, equating to 60% of their awake time, and had on average 111 SB breaks /day. SA children had 25 fewer SB breaks/ day when compared to WB (p < 0.001). Perceived reasons for engagement in SB included: boredom, enjoyment of screen activities (by children), parenting practices, curriculum pressures (by teachers), the need to sit down and learn, and child's preference for screen activities (by parents). CONCLUSIONS: Children spent 60% of their awake time being sedentary, regardless of ethnicity or school term. There were no significant ethnic differences for any of the SB outcomes except for breaks in SB. Interventions aimed at reducing SB should consider involving parents and teachers and should focus on increasing breaks in SB, especially for SA children, who are at a higher risk of cardio metabolic ill health.

Iron Pathophysiology in Stroke.

Ischemic and hemorrhagic stroke are the common types of stroke that lead to brain injury neurological deficits and mortality. All forms of stroke remain a serious health issue, and there is little successful development of drugs for treating stroke. Incomplete understanding of stroke pathophysiology is considered the main barrier that limits this research progress. Besides mitochondria and free radical-producing enzymes, labile iron is an important contributor to oxidative stress. Although iron regulation and metabolism in cerebral stroke are not fully understood, much progress has been achieved in recent years. For example, hepcidin has recently been recognized as the principal regulator of systemic iron homeostasis and a bridge between inflammation and iron regulation. This review discusses recent research progress in iron pathophysiology following cerebral stroke, focusing molecular regulation of iron metabolism and potential treatment targets.

The learning curve to achieve satisfactory completion rates in upper GI endoscopy: an analysis of a national training database.

OBJECTIVE: The aim of this study was to determine the number of OGDs (oesophago-gastro-duodenoscopies) trainees need to perform to acquire competency in terms of successful unassisted completion to the second part of the duodenum 95% of the time. DESIGN: OGD data were retrieved from the trainee e-portfolio developed by the Joint Advisory Group on GI Endoscopy (JAG) in the UK. All trainees were included unless they were known to have a baseline experience of >20 procedures or had submitted data for <20 procedures. The primary outcome measure was OGD completion, defined as passage of the endoscope to the second part of the duodenum without physical assistance. The number of OGDs required to achieve a 95% completion rate was calculated by the moving average method and learning curve cumulative summation (LC-Cusum) analysis. To determine which factors were independently associated with OGD completion, a mixed effects logistic regression model was constructed with OGD completion as the outcome variable. RESULTS: Data were analysed for 1255 trainees over 288 centres, representing 243 555 OGDs. By moving average method, trainees attained a 95% completion rate at 187 procedures. By LC-Cusum analysis, after 200 procedures, >90% trainees had attained a 95% completion rate. Total number of OGDs performed, trainee age and experience in lower GI endoscopy were factors independently associated with OGD completion. CONCLUSIONS: There are limited published data on the OGD learning curve. This is the largest study to date analysing the learning curve for competency acquisition. The JAG competency requirement for 200 procedures appears appropriate.

Factors controlling permeability of the blood-brain barrier.

As the primary protective barrier for neurons in the brain, the blood-brain barrier (BBB) exists between the blood microcirculation system and the brain parenchyma. The normal BBB integrity is essential in protecting the brain from systemic toxins and maintaining the necessary level of nutrients and ions for neuronal function. This integrity is mediated by structural BBB components, such as tight junction proteins, integrins, annexins, and agrin, of a multicellular system including endothelial cells, astrocytes, pericytes, etc. BBB dysfunction is a significant contributor to the pathogeneses of a variety of brain disorders. Many signaling factors have been identified to be able to control BBB permeability through regulating the structural components. Among those signaling factors are inflammatory mediators, free radicals, vascular endothelial growth factor, matrix metalloproteinases, microRNAs, etc. In this review, we provide a summary of recent progress regarding these structural components and signaling factors, relating to their roles in various brain disorders. Attention is also devoted to recent research regarding impact of pharmacological agents such as isoflurane on BBB permeability and how iron ion passes across BBB. Hopefully, a better understanding of the factors controlling BBB permeability helps develop novel pharmacological interventions of BBB hyperpermeability under pathological conditions.

Use of a pathway quality improvement care bundle to reduce mortality after emergency laparotomy.

BACKGROUND: Emergency laparotomies in the U.K., U.S.A. and Denmark are known to have a high risk of death, with accompanying evidence of suboptimal care. The emergency laparotomy pathway quality improvement care (ELPQuiC) bundle is an evidence-based care bundle for patients undergoing emergency laparotomy, consisting of: initial assessment with early warning scores, early antibiotics, interval between decision and operation less than 6 h, goal-directed fluid therapy and postoperative intensive care. METHODS: The ELPQuiC bundle was implemented in four hospitals, using locally identified strategies to assess the impact on risk-adjusted mortality. Comparison of case mix-adjusted 30-day mortality rates before and after care-bundle implementation was made using risk-adjusted cumulative sum (CUSUM) plots and a logistic regression model. RESULTS: Risk-adjusted CUSUM plots showed an increase in the numbers of lives saved per 100 patients treated in all hospitals, from 6.47 in the baseline interval (299 patients included) to 12.44 after implementation (427 patients included) (P < 0.001). The overall case mix-adjusted risk of death decreased from 15.6 to 9.6 per cent (risk ratio 0.614, 95 per cent c.i. 0.451 to 0.836; P = 0.002). There was an increase in the uptake of the ELPQuiC processes but no significant difference in the patient case-mix profile as determined by the mean Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity risk (0.197 and 0.223 before and after implementation respectively; P = 0.395). CONCLUSION: Use of the ELPQuiC bundle was associated with a significant reduction in the risk of death following emergency laparotomy.

Using Repeated Lysis Steps Fractionates Between Heterotrophic and Cyanobacterial DNA Extracted from Xenic Cyanobacterial Cultures.

Extracting DNA from cyanobacteria can be a challenge because of their diverse morphologies, challenging cellular structure, and the heterotrophic microbiome often present within cyanobacterial cultures. As such, even when our DNA yields are sufficient for sequencing, the percentage of reads coming from the cyanobacterial host can be low, leading to incomplete genomes spread across several scaffolds. In this research, we optimized a DNA isolation protocol using three iterative cell lysis steps to enrich the portion of DNA isolated coming from the cyanobacterial host rather than the heterotrophic microbiome. In order to utilize in-house nanopore sequencing, we faced a challenge in that our lysis protocol led to DNA shearing and a lower molecular weight DNA extract than is suitable for this sequencing technology. As such we used two bead-based size selection steps to remove shorter molecules of DNA before nanopore sequencing. EPI2ME analysis of the processed reads from the iterative lysis steps showed that in the first lysis the heterotrophic microbiome could make up more than half of all reads, but with each lysis the proportion of reads coming from these other species decreased. Using our iterative lysis protocol, we were able to sequence the genomes of two cyanobacteria isolated from fresh water sources around northern Mississippi, namely Leptolyngbya sp. BL-A-14 and Limnothrix sp. BL-A-16. The genomes of these isolates were assembled as closed chromosomes of 7.2 and 4.5 Mb for Leptolyngbya sp. BL-A-14 and Limnothrix sp. BL-A-16, respectively. Because some cyanobacteria have symbioses with their heterotrophic microbiome it is not always possible to prepare axenic cultures of these organisms, we hope our approach will be useful for sequencing xenic cultures of cyanobacteria, but we can also imagine applications in studying this microbiome specifically by focusing sequencing efforts on the first fraction.

An optimal estimation approach in stratified random sampling utilizing two auxiliary attributes with application in agricultural, demography, finance, and education sectors.

In the contemporary era of information technology, copious amounts of data are ubiquitous, generated across various sectors on a daily basis. Analyzing every unit of data is impractical due to constraints such as limited resources in terms of time, labor, and cost. In such scenarios, survey sampling becomes a recommended approach for extracting information about population parameters. The primary goal of this study is to devise an estimation method for acquiring information about population parameters. We propose an optimal estimator for an improved estimation of the population mean in stratified random sampling by leveraging the information from two auxiliary attributes. The proposed estimator's bias, mean squared error (MSE), and minimum mean squared error are determined up to the first-order approximation. It is demonstrated that, under the derived conditions, the proposed estimator theoretically outperforms existing estimators. Four population are utilized to evaluate both the performance and applicability of the proposed estimator. The percentage relative efficiency (PRE) of proposed estimator for all the populations is 178.389, 142.881, 181.383, and 152.679 respectively. The suggested estimator superior to existing estimators, as demonstrated by the numerical examples.

More than chest pain: A case of oesophageal foreign body ingestion.

BACKGROUND:  Physicians often focus on possible cardiac causes in patients presenting with chest pain. However, this case highlights a patient who presented with chest pain caused by ingestion of a foreign body after an uneventful meal eaten an hour prior to presentation. The fishbone was discovered after imaging. The article aims to raise awareness regarding the potential origins of chest pain, highlighting that it may stem from non-cardiac conditions. METHODS:  The methodology employed in this study involved conducting a case study that meticulously examined the repercussions and management strategies associated with foreign body ingestion. RESULTS:  The case report delineates the scenario of a 27-year-old male patient who inadvertently ingested a fishbone during a routine meal. It details the swift decline in clinical status, the meticulous diagnostic procedures employed, the subsequent management strategies implemented and the ultimate discharge of the patient in a stable condition. CONCLUSION:  This case highlights the importance of comprehensive history taking and considering a wide range of causes of chest pain when evaluating a patient. The foreign body ingested with the resulting cardiac complications could have been fatal if not promptly diagnosed.Contribution: This study contributed to advancing awareness surrounding foreign body ingestion, shedding light on potential complications and offering valuable insights into effective management strategies.

ZNFX1 is a Novel Master Regulator in Epigenetically-induced Pathogen Mimicry and Inflammasome Signaling in Cancer.

DNA methyltransferase and poly(ADP-ribose) polymerase inhibitors (DNMTis, PARPis) induce a stimulator of interferon (IFN) genes (STING)-dependent pathogen mimicry response (PMR) in ovarian (OC) and other cancers. We now show that combining DNMTis and PARPis upregulates expression of a little-studied nucleic-acid sensor, NFX1-type zinc finger-containing 1 protein (ZNFX1). We demonstrate that ZNFX1 is a novel master regulator for PMR induction in mitochondria, serving as a gateway for STING-dependent PMR. In patient OC databases, high ZNFX1 expression levels correlate with advanced stage disease. ZNFX1 expression alone significantly correlates with an increase in overall survival in a phase 3 trial for therapy-resistant OC patients receiving bevacizumab in combination with chemotherapy. In correlative RNA-seq data, inflammasome signaling through ZNFX1 correlates with abnormal vasculogenesis. ZNFX1 controls PMR signaling through the mitochondria and may serve as a biomarker to facilitate offering personalized therapy in OC patients, highlighting the strong translational significance of our findings. Significance statement: DNA methyltransferase and poly(ADP-ribose) polymerase inhibitors upregulate expression of a novel nucleic-acid sensor, ZNFX1 that serves as a mitochondrial gateway to STING-dependent interferon/inflammasome signaling with tumor suppressor properties in ovarian cancer.

Shiga toxin-producing Escherichia coli from raw milk cheese in Egypt: prevalence, molecular characterization and survival to stress conditions.

Raw milk cheese is considered as a risk for foodborne Shiga toxin-producing E. coli (STEC) contamination. In this study, 124 raw milk cheese samples (64 Kareish and 60 Damietta cheese samples) were assayed for the presence of STEC using molecular detection of virulence markers such as Shiga toxins (stx1 and st×2) and intimin gene (eae) and by serotyping. By PCR, 14 E. coli strains showed the presence of the stx2 gene, either single or in association with the stx1, and were considered positive for STEC. The isolated non-O157 STEC in this study (from serotypes O22:H8, O26:H11, O86:H21, O103:H2, O113:H21 and O146:H21) were inoculated in 10% skim milk and were compared to O157:H7 reference strain for their survival under different stress conditions (pH levels between 4·5 and 6·5 and salt concentrations between 1 and 6%) and 8 days of storage at refrigeration temperature (4°C). Strikingly, our results showed that O26:H11 survived significantly better than O157:H7 under acidic pH and higher salt concentration.

Comparative metabolomic profiling of Cupriavidus necator B-4383 revealed production of cupriachelin siderophores, one with activity against Cryptococcus neoformans.

Cupriavidus necator H16 is known to be a rich source of linear lipopeptide siderophores when grown under iron-depleted conditions; prior literature termed these compounds cupriachelins. These small molecules bear ß-hydroxyaspartate moieties that contribute to a photoreduction of iron when bound as ferric cupriachelin. Here, we present structural assignment of cupriachelins from C. necator B-4383 grown under iron limitation. The characterization of B-4383 cupriachelins is based on MS/MS fragmentation analysis, which was confirmed by 1D- and 2D-NMR for the most abundant analog (1). The cupriachelin congeners distinguish these two strains with differences in the preferred lipid tail; however, our rigorous metabolomic investigation also revealed minor analogs with changes in the peptide core, hinting at a potential mechanism by which these siderophores may reduce biologically unavailable ferric iron (4-6). Antifungal screening of the C. necator B-4383 supernatant extract and the isolated cupriachelin analog (1) revealed inhibitory activity against Cryptococcus neoformans, with IC50 values of 16.6 and 3.2 µg/mL, respectively. This antifungal activity could be explained by the critical role of the iron acquisition pathway in the growth and pathogenesis of the C. neoformans fungal pathogen.

Green synthesized silver nanoparticles using the plant-based reducing agent Matricaria chamomilla induce cell death in colorectal cancer cells.

OBJECTIVE: There is a need to treat cancer cells with safe and natural nanoparticles to avoid the side effects of chemotherapeutic agents. Chamomile is considered a safe, natural plant with anticancer activity. We synthesize simple, inexpensive, and eco-friendly silver nanoparticles (SNs) using Chamomile (CHM) to tune their anticancer properties. MATERIALS AND METHODS: SN-CHM was synthesized by reducing 1 mM silver nitrate aqueous solution in 100 mL with the aqueous ethanolic flower extract of CHM (18 mg/mL, w/v). The reaction proceeded overnight at 600 rpm and 28°C. SN-CHM was characterized for their % yield, average diameter, charge, morphology, and silver release. Moreover, SN-CHM was investigated for its antioxidant and anticancer activities at 200 µg/mL and 5 mg/ mL, respectively. RESULTS: A 59.12% yield and a uniform SN-CHM size of 115 ± 3.1 nm with a ζ-potential of -27.67 ± (-3.92) mv were observed. The UV-visible absorption showed shifts from 379.5 to 383.5 nm for CHM and SN-CHM, respectively. Moreover, Ag+ was ultimately released from SN-CHM after 5 h. Fourier Transform Infrared Spectroscopy (FT-IR) showed characteristic absorption peaks of CHM and produced SN-CHM. Furthermore, SN-CHM showed moderate antioxidant activity. SN-CHM inhibited the % viability of SW620 and HT-29 cell lines at 20 µM. SN-CHM may also greatly upregulate the apoptotic gene BAX while considerably downregulating the anti-apoptotic genes BCL2 and BCL-Xl. CONCLUSIONS: CHM can be a safe soft drink, especially when conjugated with Ag ions as anticancer NPs. SN-CHM is considered potent anticancer activity against SW620, and HT-29 cell lines.

Litoarbolide A: an undescribed sesquiterpenoid from the Red Sea soft coral Litophyton arboreum with an in vitro anti-malarial activity evaluation.

Soft corals distributed across the Red Sea coasts are a rich source of diverse and bioactive natural products. Chemical probing of the Red Sea soft coral Litophyton arboreum led to isolation and structural characterization of an undescribed sesquiterpenoid, litoarbolide A (1), along with 14 previously reported metabolites (2-15). The chemical structures of the isolates were assigned based on NMR as well as high resolution electrospray ionization mass spectrometry (HR-ESI-MS) data. Litoarbolide A is supposed to be the biosynthetic precursor to other sesquiterpenoids, which formed via further post-translational modifications. Furthermore, these metabolites were evaluated for anti-malarial activity, where only the acyclic sesquiterpenoid of a sec-germacrane nucleus (7) showed an activity against chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC50 at 3.7 and 2.2 mg/mL, respectively. Moreover, the isolated metabolites were all non-toxic to the Vero cell line. These findings support the consideration of L. arboreum in further natural anti-malarial studies.

Application of the LINEX Loss Function with a Fundamental Derivation of Liu Estimator.

For a variety of well-known approaches, optimum predictors and estimators are determined in relation to the asymmetrical LINEX loss function. The applications of an iteratively practicable lowest mean squared error estimation of the regression disturbance variation with the LINEX loss function are discussed in this research. This loss is a symmetrical generalisation of the quadratic loss function. Whenever the LINEX loss function is applied, we additionally look at the risk performance of the feasible virtually unbiased generalised Liu estimator and practicable generalised Liu estimator. Whenever the variation σ 2 is specified, we get all acceptable linear estimation in the class of linear estimation techniques, and when σ 2 is undetermined, we get all acceptable linear estimation in the class of linear estimation techniques. During position transformations, the proposed Liu estimators are stable. The estimators' biases and hazards are calculated and evaluated. We utilize an asymmetrical loss function, the LINEX loss function, to calculate the actual hazards of several error variation estimators. The employment of δ P (σ), which is easy to use and maximin, is recommended in the conclusions.

Bayesian Estimation of Different Scale Parameters Using a LINEX Loss Function.

The LINEX loss function, which climbs exponentially with one-half of zero and virtually linearly on either side of zero, is employed to analyze parameter analysis and prediction problems. It can be used to solve both underestimation and overestimation issues. This paper explained the Bayesian estimation of mean, Gamma distribution, and Poisson process. First, an improved estimator for µ 2 is provided (which employs a variation coefficient). Under the LINEX loss function, a better estimator for the square root of the median is also derived, and an enhanced estimation for the average mean in such a negatively exponential function. Second, giving a gamma distribution as a prior and a likelihood function as posterior yields a gamma distribution. The LINEX method can be used to estimate an estimator λ B L ^ using posterior distribution. After obtaining λ B L ^ , the hazard function h B L ^ and D B L ^ the function of survival estimators are used. Third, the challenge of sequentially predicting the intensity variable of a uniform Poisson process with a linear exponentially (LINEX) loss function and a constant cost of production time is investigated using a Bayesian model. The APO rule is offered as an approximation pointwise optimal rule. LINEX is the loss function used. A variety of prior distributions have already been studied, and Bayesian estimation methods have been evaluated against squared error loss function estimation methods. Finally, compare the results of Maximum Likelihood Estimation (MLE) and LINEX estimation to determine which technique is appropriate for such information by identifying the lowest Mean Square Error (MSE). The displaced estimation method under the LINEX loss function was also examined in this research, and an improved estimation was proposed.

Ridge Regression Method and Bayesian Estimators under Composite LINEX Loss Function to Estimate the Shape Parameter in Lomax Distribution.

In this paper, the Ridge Regression method is employed to estimate the shape parameter of the Lomax distribution (LD). In addition to that, the approaches of both classical and Bayesian are considered with several loss functions as a squared error (SELF), Linear Exponential (LLF), and Composite Linear Exponential (CLLF). As far as Bayesian estimators are concerned, informative and noninformative priors are used to estimate the shape parameter. To examine the performance of the Ridge Regression method, we compared it with classical estimators which included Maximum Likelihood, Ordinary Least Squares, Uniformly Minimum Variance Unbiased Estimator, and Median Method as well as Bayesian estimators. Monte Carlo simulation compares these estimators with respect to the Mean Square Error criteria (MSE's). The result of the simulation mentioned that the Ridge Regression method is promising and can be used in a real environment. where it revealed better performance the than Ordinary Least Squares method for estimating shape parameter.