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Background: Considering the lack of a standardized definition for weight recurrence (WR), the prevalence and predictors of WR remain inconsistent., Methods: The prospective study was conducted on 1939 individuals who underwent bariatric surgery;66.8% underwent sleeve gastrectomy (SG), 33.2%, underwent gastric bypass (GB)[of them 87% one-anastomosis gastric bypass (OAGB), and 13% Rue and Y gastric bypass (RYGB)]. During a follow-up of 72 months, the prevalence of WR ranged from 13.5% to 35.5% according to five different definitions. The generalized estimated equation method was used to assess weight changes, excess weight loss (EWL%), and body composition (fat mass (FM), fat-free mass (FFM)and FFM loss/weight loss% (FFML/WL%)) by a bioelectrical impedance analyzer. Stepwise logistic regression models were applied to determine the independent predictors of WR., Results: Among 1939 participants followed up for 72 months, WR definitions were applied to 650 patients (75.4% females) with an average BMI of 44.3 ± 5.4 kg/m 2 ,491 (75.5%) and 159 (24.5%) of whom underwent SG and GB, respectively. WR group had relatively higher weights and FM and lower EWL%. A WR turning point was observed at 24 months post-surgery (Ptime before & after 24 months<0.001). The most significant risk factors for WR included SG (in all WR definitions), a younger age (in four out of five definitions), and a higher baseline BMI (in three out of five definitions)., Conclusion: The prevalence and predictors of WR varied greatly depending on the definition applied. The prominent risk factors of WR included SG, younger age, and a higher baseline BMI., Competing Interests: Declaration of Competing Interest The authors declare that they have no financial or non-financial competing interests., (Copyright © 2024 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.)

The lack of readily available methods for estimating high-resolution near-surface relative humidity (RH) and the incapability of weather stations to fully capture the spatiotemporal variability can lead to exposure misclassification in studies of environmental epidemiology. We therefore aimed to predict German-wide 1 × 1 km daily mean RH during 2000-2021. RH observations, longitude and latitude, modelled air temperature, precipitation and wind speed as well as remote sensing information on topographic elevation, vegetation, and the true color band composite were incorporated in a Random Forest (RF) model, in addition to date for capturing the temporal variations of the response-explanatory variables relationship. The model achieved high accuracy (R 2  = 0.83) and low errors (Root Mean Square Error (RMSE) of 5.07%, Mean Absolute Percentage Error (MAPE) of 5.19% and Mean Percentage Error (MPE) of - 0.53%), calculated via ten-fold cross-validation. A comparison of our RH predictions with measurements from a dense monitoring network in the city of Augsburg, South Germany confirmed the good performance (R 2  ≥ 0.86, RMSE ≤ 5.45%, MAPE ≤ 5.59%, MPE ≤ 3.11%). The model displayed high German-wide RH (22y-average of 79.00%) and high spatial variability across the country, exceeding 12% on yearly averages. Our findings indicate that the proposed RF model is suitable for estimating RH for a whole country in high-resolution and provide a reliable RH dataset for epidemiological analyses and other environmental research purposes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

In recent years, growing consideration of the concepts of ecological sustainability, environmentally friendly, recyclability, non-toxicity and biodegradability towards a green environment, have led scientists to focus on the utilization of natural fibers as green reinforcing agents for improving thermal, physical, and mechanical characteristics of composites. In this way, cellulose and lignin (nano) materials are receiving global attention due to their unique and potentially useful features, containing abundance, renewability, low cost, excellent physical-mechanical properties, environmental friendliness, and low weight. Therefore, this research, addressed a survey of the literature on extending the performance of phenol-formaldehyde (phenolic) composites reinforced by cellulose and lignin nano materials that were explored in the last decade. Physical, mechanical behavior and thermal stability of the phenolic composites were comprehensively examined. Indeed, different types of phenolic composites modified with nanocellulose and nanolignin have been made using various advanced synthesis processes. The results were unanimous and highlighted the remarkable effect of nanocellulose and nanolignin on improving the overall performance of the fabricated composites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background and Aims: The association between obesity severity and duration with the transition from metabolically healthy obese/overweight (MHO) phenotype to metabolically unhealthy obese (MUO) phenotype is not well understood., Methods and Results: This study includes the Tehran Lipid and Glucose Study participants who were initially classed as MHO. Cumulative excess weight (CEW) and cumulative excess waist circumference (CEWC) scores, which represent the accumulation of body mass index and waist circumference deviations from expected values over time (kg/m 2 ∗ y and cm ∗ y, respectively), were calculated until the transition from MHO to MUO or the end of follow-up. The sex-stratified association of CEW and CWEC with the transition from MHO to MUO was investigated by time-dependent Cox models, adjusting for confounders. Out of 2525 participants, 1732 (68.5%) were women. During 15 years of follow-up, 1886 (74.6%) participants transitioned from MHO to MUO. A significant association was found between CEW and CEWC quartiles with the development of MUO among women participants (fully adjusted hazard ratios in the fourth quartile of CEW and CEWC [95% (CI)]:1.65 [1.37-1.98] and [95% CI]: 1.83 [1.53-2.19]). There was no significant association between CEW and CEWC with the MHO transition to MUO among men participants., Conclusion: Over 15 years of follow-up in TLGS, general and central obesity accumulation was associated with the increased transition from MHO to MUO among women participants. More research with a larger sample size is needed to confirm and explain why the results are different for men and women., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to disclose., (Copyright © 2022 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Aims: Discrepant results have been demonstrated regarding the cardiovascular (CV) risk of populations with metabolically healthy overweight/obesity (MHO) who were transitioned into metabolically unhealthy states. So, the objective of this systematic review and meta-analysis was to estimate the risk of cardiovascular diseases (CVD) incidence in individuals with transitional MHO phenotype., Data Synthesis: A literature review was done in PubMed, Scopus, EMBASE, and google scholar databases. Pooled HRs for all fatal and nonfatal CV events were computed using random-effect models for transitional MHOs in general as well as for each sex subgroup separately. This systematic review and meta-analysis included a total of 7 prospective observational studies with a total of 7,720,165 participants, published between 2018 and 2020. The mean follow-up duration of participants was 11.7 (5.5) years. Overall, the transitional MHO individuals had a significant risk of CVD incidence [HR = 1.42, 95% CI (1.24-1.60)]. In addition, in both male and female subgroups, unstable MHO phenotype demonstrated a significant CVD risk and HRs for incident CVD in males and females were 1.51 (1.07-1.96) and 1.71 (1.08-2.34), respectively., Conclusion: Transition from MHO to unhealthy state throughout follow-up elevated the risk of CVD in both male and female groups. This can explain the association between MHO and incidence of CV events especially with longer follow up period., Registration Code in Prospero: CRD42021270225., (Copyright © 2022 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Background: The clinical significance of metabolic syndrome (MetS) during adolescence and its association with adulthood adverse outcomes is a controversial issue. This study aimed to investigate the association of MetS and metabolic phenotypes with a high carotid intima-media thickness (CIMT) in early adulthood., Methods: MetS was defined as proposed by Cook, de Ferranti, the National Cholesterol Education Program (NCEP), and the pediatric International Diabetes Federation (IDF). Metabolic phenotypes were defined based on the binary clustering of cardiovascular risk factors. The participants were adolescent's individual selected from a large cohort study and followed for 18.2 years. Multivariate-adjusted odds ratios (ORs) were calculated for a high CIMT incidence (≥95th percentile)., Results: In this study, 862 adolescents (52.3% males), with the mean age of 13.4 ± 2.2 years, were included. The presence of MetS, based on the definitions proposed by Cook (OR = 1.90, 95% CI: 1.01-3.57, P = 0.046) and de Ferranti (OR = 1.74; 95% CI: 1.04-2.90, P = 0.033), was associated with the increased risk of a high CIMT in early adulthood. Metabolic phenotypes, including high waist circumference (WC)/hypertension (HTN), high WC/low high-density lipoprotein-cholesterol (HDL-C), and high triglyceride (TG)/high WC, showed higher risks of a high CIMT. However, these positive associations become insignificant after adjusting for the adulthood BMI, except for the high WC/low HDL-C phenotype (OR = 2.04, 95% CI: 1.02-4.11, P = 0.044)., Conclusion: The high WC/low HDL-C phenotype had a better predictive value and could be used as a simpler alternative for MetS to identify adolescents with a higher risk of high CIMT during early adulthood., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background and Aims: Over the past few years, obesity and metabolic syndrome prevalence among children and adolescence have an increasing trend. This study aims to investigate the association of obesity phenotypes during childhood and adolescence with early adulthood carotid intima-media thickness (CIMT)., Methods and Results: Participants were divided into four obesity phenotypes: Metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). Participants were followed for 18 years. Multivariate-adjusted Risk Ratios (RRs) were calculated for high CIMT (≥95% percentile) incidence. In this cohort study 1220 children and adolescents with the average age of 10.9 ± 4.0 years were included. CIMT values had a significantly increasing trend from MHNW to MUO group (p for trend<0.001). Individuals with normal weight status, even with an unhealthy metabolic profile did not have higher risk of high CIMT. Similarly, Children with obesity but healthy metabolic status was not at higher risk. On the other hand, MUO phenotype during childhood was associated with increased risk of high CIMT in early adulthood (RR = 2.13, 95%CI (1.02-4.48)). This association became insignificant for all obesity phenotypes after adjusting for adulthood BMI., Conclusion: Adulthood CIMT has an increasing trend based on childhood and adolescence obesity phenotypes from MHNW to MUO. Children with MUO phenotype was the only ones that had an increased risk of high CIMT incidence in early adulthood., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

In this research, the simultaneous absorption of Salmeterol (SAL) and Fluticasone (FLU) in Seroflo spray was investigated using a spectrophotometric device via employing continuous wavelet transform (CWT) and radial basis function neural network (RBF-NN) methods. Root mean square error (RMSE) related to the RBF model was obtained 3.17 × 10 -13 and 1.41 × 10 -13 for SAL and FLU, respectively. Limit of detection (LOD) and limit of quantification (LOQ) corresponding to the CWT method were 0.004, 0.280 μg/mL, and 0.431, 0.479 μg/mL for SAL and FLU, respectively. Root mean square error (RMSE) of SAL and FLU was obtained 3.17 × 10 -13 and 1.41 × 10 -13 , respectively in RBF-NN method. In the end, the results obtained from all methods were compared with the high-performance liquid chromatography (HPLC) as a reference method. According to the one-way analysis of variance with a 95% confidence level, there is no significant difference between the proposed techniques and HPLC. Therefore, chemometrics methods are sufficiently accurate, as the reference method for the analysis of drugs. The suggested methods are simple, fast, and cheap. Also, there is no need for pre-preparation steps. These methods can be used for quality control laboratories in the pharmaceutical industry., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background and Objectives: The prevalence of both obesity and type 2 diabetes has increased in recent years. In this study, we aimed to evaluate the prevalence of obesity and type 2 diabetes and to investigate the contribution of obesity to the increased prevalence of type 2 diabetes in urban and rural Iranian communities., Methods: This study was based on four surveys from the Surveillance Survey of Risk Factors of Non-communicable Diseases (SuRFNCD), conducted in 2005, 2007, 2011, and 2016. The contribution of general and abdominal obesity to the prevalence of type 2 diabetes was determined based on the population attributable fraction (PAF)., Results: The mean (95% CI) age and body mass index (BMI) of the participants were 36.9 years (36.8-36.9) and 25.9 kg/m 2 (25.9-26.0), respectively. The increasing rates of general obesity and diabetes were 37% and 80% among urban residents and 63% and 68% among rural residents, respectively. The PAF of general obesity and abdominal obesity to the prevalence of type 2 diabetes was 20.2% and 33.4% in urban residents and 11.8% and 21.0% in rural residents, respectively., Conclusion: The prevalence of both obesity and type 2 diabetes has increased over the past 12 years. Besides, general and abdominal obesity played a substantial role in increasing the prevalence of type 2 diabetes in both urban and rural populations., (Copyright © 2021 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.)

In this study, a fast, low-cost, accurate, and precise spectrophotometric method based on the continuous wavelet transform (CWT) was assayed to determine dorzolamide (DOR) and timolol (TIM) in an eye drop sample simultaneously. Different wavelet families were investigated to select the best family for analyzing the DOR and TIM. The Mexican hat wavelet (MHW) family with the wavelength of 281 nm and Gaussian wavelet family (gaus2) in the wavelength of 267 nm were found for the simultaneous analysis of DOR and TIM, respectively. Mean recovery values of synthetic mixtures were found 97.44%±2.63 and 99.18%±4.00 for DOR and TIM, respectively. The root mean square errors (RMSE) of DOR and TIM were achieved 0.5550 and 0.3306, respectively. Eye drop as a real sample was analyzed by spectrophotometry coupled with the CWT technique, as well as high-performance liquid chromatography (HPLC) as a reference method. The obtained results were compared with each other by the one-way analysis of variance (ANOVA) test and there was no significant difference between them., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objective: Obesity and related health risk in different obesity phenotypes has always been a controversial subject. The present study was conducted with the aim of investigating the risk of kidney function decline (KFD) incidence in different abdominal obesity phenotypes., Methods: In this prospective observational cohort study, 7002 individuals (56.1% female), aged ≥20 years, were followed for the incidence of KFD defined as 40% decline in eGFR. Abdominal obesity was defined based on waist circumference cut-offs ≥89/91cm for men/women, respectively. Metabolic health was defined as ≤1 criterion of the metabolic syndrome criteria, according to the Joint Interim Statement (JIS) definition., Results: At baseline 4273 individuals (61.0%) were abdominally obese, among whom, 1188 (27.8%) belonged to the metabolically healthy abdominal obese (MHAO) phenotype. Totally, 251 incidences of KFD was indicated throughout the 12-year follow-up. After adjusting for the confounding variables, MHAO phenotype was not associated with increased risk of KFD in both males and females. Furthermore, results indicated that hazard ratios (HRs) for incidence of KFD did not increase in males with unhealthy obesity phenotypes. However, females with metabolically unhealthy abdominal obese (MUAO) phenotype had increased risk of KFD., Conclusion: Findings of this study indicated that MHAO phenotype was not associated with KFD incidence, regardless of the participants gender. Furthermore, MUAO phenotype was associated with higher risk of KFD only in females. Further studies with longer follow up and larger sample size are needed to shed more light upon the regarded relationship and the influential role of gender., (Copyright © 2020 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.)

Background and Aim: Increased adiposity is associated with insulin resistance and glycemic disturbances. We aimed to determine whether childhood overweight or obesity are independent factors in predicting adulthood dysglycemia (prediabetes or type 2 diabetes)., Methods and Results: In this population-based cohort study, 1290 normoglycemic subjects aged 3-11 years were followed for incidence of dysglycemia. Cox-proportional hazard models were employed to evaluate the association of obesity and overweight with incidence of dysglycemia by adjustments for age, sex, parental risk factors and baseline individual risk factors. The participants, with a mean age of 7.7 ± 2.5 years, were followed for a median of 14.9 years. During follow up, 158 subjects developed dysglycemia (18 type 2 diabetes, 140 prediabetes), contributing to a total cumulative incidence of 24.7%. The unadjusted HR for developing adult dysglycemia were 1.6 (95% CI; 1.0-2.4) and 1.7 (95% CI; 1.0-3.0) in overweight and obese children, respectively. Further adjustments for age, sex, parental risk factors and baseline individual risk factors changed the results in both overweight and obese children., Conclusion: These findings show that overweight or obesity in childhood have no independent role for developing adulthood dysglycemia., Competing Interests: Declaration of Competing Interest The authors claimed that they have no potential conflicts of interest to disclose., (Copyright © 2019 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Background: The Beck Depression Inventory (BDI) has been frequently employed as a measure of depression in studies of obesity, with the majority of studies reporting an improvement in scores following weight loss after bariatric surgery. However, the effects of different bariatric techniques on depression score improvement is uncertain., Method: The study included 685 obese patients who underwent laparoscopic sleeve gastrectomy (SG) (n = 443) or gastric bypass (GB) (n = 242) and completed BDIs at baseline and 1 year after surgery., Results: Mean age of the patients was 38.7 ± 10.9 (84.8% female), and mean body mass index (BMI) was 45.1 ± 6.0 kg/m 2 . One year after surgery, excess weight loss (EWL %) in the GB group was more than the SG group (65.4% vs 62.8% P = 0.02). At baseline, 29.9% of patients had BDI scores in the normal range (0-9), and respectively 32.4 %, 28.3 % and 9.3 % had mild (10-18), moderate (19-29) and sever (+30) depression score; these corresponding values after 1 year were 60.6, 23.2, 11.8 and 4.4%. Overall, BDI scores fell in both surgery groups after 1 year, in the GB group it was 17.2 ± 10.5 vs 11.1 ± 9.6, and for the SG group 16.1 ± 10.2 vs 9.6 ± 8.9. However BDI score change (ΔBDI) was not significantly different between two surgery groups (-6.04 ± 10.6 vs -6.4 ± 9.5, P = 0.149)., Conclusion: Bariatric surgery had a beneficial effect on weight reduction and BDI score regardless of its type. Further studies with longer follow-up and more samples are needed to clarify the differences between bariatric procedures., (Copyright © 2019 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.)

In this study, the ELP sequence was fused to human interferon-γ (hIFN-γ) and hIFN-γ-ELP fusion protein accumulated with high levels of yield and purity, compared with the corresponding unfused hIFN-γ protein. The hIFN-γ was exclusively produced in the form of insoluble inclusion bodies while the hIFN-γ was relatively soluble when expressed as an ELP fusion protein. The insoluble inclusion bodies were then solubilized under denaturing conditions, refolded in the presence of arginine and purified by single-step ion-exchange chromatography. The fusion to ELP signidficantly increased the accumulation of hIFN-γ by 10-fold with a stable expression on average of 46.85% of total soluble protein (TSP). Furthermore, three rounds of Inverse Transition Cycling (ITC) purification increased overall purity of the hIFN-γ-ELP to 98 ± 5%. The recovery amount of the fusion protein found to be dependent on the NaCl concentration, with increase of NaCl concentration, a greater fraction of the hIFN-γ-ELP was aggregated. However, due to the presence of an aliphatic guest residue in ELP sequence, the high concentration of salt was necessary to trigger the inverse phase transition of hIFN-γ-ELP fusion protein. Moreover, recombinant hIFN-γ and hIFN-γ-ELP proteins purified from E. coli possessed a relatively similar bioactivity based on viral cytopathic assay., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In the present study, artificial neural networks (ANNs) and support vector regression (SVR) as intelligent methods coupled with UV spectroscopy for simultaneous quantitative determination of Dorzolamide (DOR) and Timolol (TIM) in eye drop. Several synthetic mixtures were analyzed for validating the proposed methods. At first, neural network time series, which one type of network from the artificial neural network was employed and its efficiency was evaluated. Afterwards, the radial basis network was applied as another neural network. Results showed that the performance of this method is suitable for predicting. Finally, support vector regression was proposed to construct the Zilomole prediction model. Also, root mean square error (RMSE) and mean recovery (%) were calculated for SVR method. Moreover, the proposed methods were compared to the high-performance liquid chromatography (HPLC) as a reference method. One way analysis of variance (ANOVA) test at the 95% confidence level applied to the comparison results of suggested and reference methods that there were no significant differences between them. Also, the effect of interferences was investigated in spike solutions., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Curcumin is a hydrophobic polyphenolic compound derived from turmeric rhizome, which consists about 2-5% of the total rhizome content and is a more valuable component of turmeric. For reducing the drawbacks of conventional extraction (using organic solvents) of curcumin, the water as a clean solvent was used for extracting curcumin. Subcritical water extraction (SWE) experimental setup was fabricated in a laboratory scale and the influences of some parameters (e.g. extraction temperature, particle size, retention time and pressure) on the yield of extraction were investigated. Optimum extraction conditions such as SWE pressure of 10bar, extractive temperature of 140°C, particle size of 0.71mm and retention time of 14min were defined. The maximum amount of curcumin extracted at the optimum condition was 3.8wt%. The yield of curcumin extraction was more than 76wt% with regards to the maximum possible curcumin content of turmeric, as known to be 5%. The scanning electron microscope (SEM) images from the outer surface of turmeric, before and after extraction, clearly demonstrated the effect of each parameter; changes in porosity and hardness of turmeric that is directly related to the amount of extracted curcumin in process optimization of the extraction parameters., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Poly (N-isopropylacrylamide) (PNIPAAm) is a thermosensitive polymer with various biomedical applications. We examined molecular weight (MW)-dependent cytotoxicity of PNIPAAm. Our results indicated that low-MW PNIPAAm (degree of polymerization (DP)=35) is inherently toxic to cells. Moderate-MW PNIPAAms with their DP between 100 and 200 are non-cytotoxic. When cells are seeded on top of a polymer-coated surface, PNIPAAm with a higher MW (DP=400) shows non/low cytotoxicity, while when monolayer cells are exposed to the polymer solution, cell viability drops drastically. This may be due to lack of nutrient and oxygen rather than intrinsic toxicity of the polymer., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Proteolytic cleavage in an exposed loop of human tartrate-resistant acid phosphatase (TRAcP) with trypsin leads to a significant increase in activity. At each pH value between 3.25 and 8.0 the cleaved enzyme is more active. Substrate specificity is also influenced by proteolysis. Only the cleaved form is able to hydrolyze unactivated substrates efficiently, and at pH >6 cleaved TRAcP acquires a marked preference for ATP. The cleaved enzyme also has altered sensitivity to inhibitors. Interestingly, the magnitude and mode of inhibition by fluoride depends not only on the proteolytic state but also pH. The combined kinetic data imply a role of the loop residue D158 in catalysis in the cleaved enzyme. Notably, at low pH this residue may act as a proton donor for the leaving group. In this respect the mechanism of cleaved TRAcP resembles that of sweet potato purple acid phosphatase.

Purple acid phosphatases are metal-containing hydrolases. While their precise biological role(s) is unknown, the mammalian enzyme has been linked in a variety of biological circumstances (e.g., osteoporosis) with increased bone resorption. Inhibition of the human enzyme is a possible strategy for the treatment of bone-resorptive diseases such as osteoporosis. Previously, we determined the crystal structure of pig purple acid phosphatase to 1.55A and we showed that it is a good model for the human enzyme. Here, a study of the pH dependence of its kinetic parameters showed that the pig enzyme is most efficient at pH values similar to those encountered in the osteoclast resorptive space. Based on the observation that phosphotyrosine-containing peptides are good substrates for pig purple acid phosphatase, peptides containing a range of phosphotyrosine mimetics were synthesized. Kinetic analysis showed that they act as potent inhibitors of mammalian and plant purple acid phosphatases, with the best inhibitors exhibiting low micromolar inhibition constants at pH 3-5. These compounds are thus the most potent organic inhibitors yet reported for the purple acid phosphatases.