Decrease In Percentage Of Weight Research Articles

Synergistic integration of nickel, porous silicon, and thermally reduced graphene oxide for solid‐state hydrogen energy storage

AbstractSolid‐state hydrogen storage using metal hydrides offers the potential for high energy storage capacities. However, the requirement for high‐temperature operations (above 400°C) and challenges with heat exchange are significant drawbacks. From this perspective, adsorption on porous materials presents a viable solution to these challenges. Carbon nanostructures, such as graphene and graphene oxide (GO) derivatives, are well‐suited for hydrogen storage because of their lightweight nature, low density, and large surface area. However, the primary obstacle for practical applications is the poor storage capacity of carbon nanostructures under ambient conditions. Utilizing a cost‐effective transition element such as nickel as a catalyst offers significant potential for storing hydrogen in atomic and molecular forms by invoking the spillover mechanism. Thermally reduced graphene oxide (TrGO) modifies the surface, providing abundant active sites that attract hydrogen effectively. Porous silicon (PS) enhances the surface properties of graphene sheets, attracting hydrogen to the surface. The current study assesses a synthesized TrGO, PS, and Ni composition to leverage their individual properties for hydrogen storage. Field‐emission scanning electron microscopy examines the sheet structure of TrGO (used as the host material) and the incorporation of PS and Ni on its surface. The calculated specific surface area of TrGO is ~450 m2 g−1. X‐ray diffraction is used to identify the various phases in the composition, while Raman spectroscopy measures the degree of disorder within the composition. The pressure‐composition isotherms reveal hydrogen storage capacities of ~6.53 wt% for the TrGO + PS composition and ~2.43 wt% for the TrGO + PS + Ni composition. Despite the decrease in weight percentage of TrGO + PS + Ni due to the higher Ni content, dissociation enhances the adsorption rate from 0.35 to 0.53 wt% h−1.

High-temperature effect on the mechanical behavior of recycled fiber-reinforced concrete containing volcanic pumice powder: An experimental assessment combined with machine learning (ML)-based prediction

The increasing volume of waste generated by various activities has increased interest in using waste to create sustainable construction materials to achieve possible benefits. In addition, using recycled materials to produce fresh concrete is a desirable option because of its low cost, lower landfill space requirement, and the completed concrete quality. Therefore, an experimental inquiry is undertaken to ascertain the impacts of up to 20 wt% cement displaced by Volcanic Pumice Powder (VPP) with the incorporation of 1% and 2% Recycled Nylon Fiber (RNF) on the mechanical properties of concrete composites following room temperature to high-temperature (600 °C) exposure. Fresh concrete characteristics tests were performed, including slump, compacting factor, Kelly ball penetration, and density. The heat resistance of the concrete was then measured by calculating the percentage decrease in weight, the splitting tensile strength, and the compressive strength of the specimens. Heating mainly raised VPP's pozzolanic reactivity and lowered high vapor pressure through melting RNF. Therefore, VPP and RNF-treated concrete had superior mechanical performance than control concrete even when exposed to elevated temperatures. Further, the microstructural modifications brought on by RNF and VPP additions were also explored by deploying Scanning Electron Microscopy (SEM). The use of VPP in concrete led to an improvement in fresh properties, while RNF demonstrated deterioration in the same qualities. Despite this, supervised machine learning techniques are a central focus of this investigation because of their potential to predict concrete characteristics accurately. To predict the fresh and mechanical characteristics of concrete, both the Random Forest (RF) and the K-Nearest Neighbors (KNN) algorithm, along with their ensemble model counterparts, were explored. The outcomes revealed that RNF and VPP considerably improved the concrete's heat resilience and mechanical characteristics and halted the concrete composites' explosive spalling behavior at 600 °C temperatures. To prevent strength loss at high temperatures, it was discovered that adding 1% RNF content to concrete with 10% VPP was the best combination. In addition, the high coefficient correlation (R2) value of the RF and the ensemble model indicates great accuracy in outcome prediction, while the low R2 value of the KNN model indicates that the KNN model is less accurate.

Retatrutide as a Novel Treatment for Obesity and Type 2 Diabetes

Retatrutide is a triple hormone agonist of the receptors of glucagon-like peptide 1, glucose-dependent insulinotropic polypeptide (GIP) and glucagon that can be administered subcutaneously once a week. Different doses and escalation schedules of retatrutide were evaluated in 2 phase 2 American trials of subjects with obesity (n=338) and type 2 diabetes (n=281). In the obesity trial of 48 week-duration, percentage change in body weight from baseline after 24 weeks and 48 weeks were the primary and secondary outcomes respectively. At 24 weeks, the mean percentage decrease in weight ranged from 7.2% to 17.5% across retatrutide groups versus 1.6% with placebo. At 48 weeks, the decrease was 8.7% to 24.2% versus 2.1% with placebo. In the diabetes trial, the primary endpoint was a change in glycated hemoglobin (HbA1c) values from baseline to week 24. This trial included an active treatment group receiving dulaglutide 1.5mg once weekly. Secondary endpoints included change in HbA1c and body weight at 36 weeks. At 24 weeks, mean HbA1c reductions were 0.43% to 2.02% with retatrutide, 1.4% with dulaglutide and 0.01% with placebo. At 36 weeks, mean percentage weight reductions were 3.2% to 16.9% with retatrutide, 2.0% with dulaglutide and 3.0% with placebo. While the decrease in HbA1c levels reached a plateau at 24 weeks, weight loss in the 2 studies was progressive without evidence of attenuation effect up to the end of follow-up at 36-48 weeks. The most common adverse effects of retatrutide were gastrointestinal (GI) such as nausea, diarrhea, vomiting and constipation reported by 13-50% in the retatrutide groups compared with 35% in the dulaglutide group, and 13% in the placebo group. Discontinuation rates due to adverse effects were also higher with retatrutide being 16-17% compared with 2% with dulaglutide and 0-4% with placebo. In summary, retatrutide is highly effective drug in causing substantial weight loss and HbA1c reduction. Yet, tolerance to this drug seems sub-optimal. Phase 3 trials are urgently needed to clarify efficacy and safety of retatrutide.

Volume Assessment in Paediatric Hemodialysis Using Lung Ultra Sonography

Background: It is a significant challenge clinically to optimize the weight of children and infants. It is our hypothesis that in children receiving dialysis fluid overload can be quantified using lung ultrasound. 
 Objectives: 
 1. To determine the frequency of diagnosing pulmonary edema using lung ultrasound and clinical examination.
 2. To determine association of percentage decrease in weight with number of B-lines in children with renal failure undergoing hemodialysis Methods: This cross sectional study was conducted in Division of Pediatric Nephrology, Paediatric unit II, Mayo Hospital
 Lahore from June 2020 till December 2020 after approval of hospital committee. Patients aged 6 to 16 years undergoing regular hemodialysis after chronic kidney disease were enrolled. Lung ultrasound examinations were performed before start of dialysis and after completion of dialysis. B lines were measured on the ultrasound along with comparing the proportional increase in weight from the target weight. Results: Eighty one lung ultrasound assessments were performed in total. Mean age was 10.4±3.3 years. There were 56(69.1%) males and 25 (30.8%) female patients. Mean percentage decrease in weight was 5.5±2.4% before dialysis and 0.96±0.6% after dialysis, p-value

Evaluation of chitosan and silver nanoparticles Against isolated pathogens from Mulberry Silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) under laboratory conditions.

This study aims to isolate and identify certain bactеrial and fungal pathogеns from silkworm, Bombyx mori L. such as promising chitosan, plus silvеr nanoparticlеs as its antimicrobial activity undеr laboratory condition. Silkworm, B. mori (H1xKKxG2xV2-Bolgaria) eggs werе attained from Sеriculture Rеsearch Cеntеr from Giza Governorate, Egypt. Chitosan and silvеr nanoparticlеs matеrials were assembled at the laboratory of Biochеmistry Departmеnt, Faculty of Agriculturе, Al-Azhar University, Cairo, Egypt. Herein total of 7 bactеrial and 5 fungal were isolatеd from the еxtеrnal and internal silkworm larvae. As a result, the mean percentage decrease in weight was elevated in diseased fifth instars (88%) compared to fourth diseased instars (62%). In addition, two bactеrial spеcies isolatеd from the infectеd larvae were identified as follows: Staphylococcus aurеus and Enterococcus faеcalis, whereas thrее fungal spеcies were isolatеd as follows: Aspergillus flavus, Aspergillus tamarii and Beauveria bassiana. Transmission elеctron microscopе imaging demonstrated the morphological propеrties and surfacе appеarance of silvеr and chitosan nanoparticlеs which havе a nеarly sphеrical shapе and smooth surfacе. The avеrage particlе size of 18.7 - 26.0 nm and 18.8 to 21.8 nm of silvеr and chitosan nanoparticles were recordеd. Furthermore, the highеst activity among nanoparticlеs tested against all pathogеnic bacteria and fungi isolatеd and idеntified in our study was rеcordеd by chitosan at 100 µg/ml in sеries, whilst silvеr nanoparticle еxhibitеd modеrate antibacterial and antifungal activity.

A Comparative Study of Pre-Engineered and Conventional Multi-Span Industrial Building

Steel is one of the oldest construction materials and become a popular construction material in late seventeenth and eighteenth century. Environment friendly, rapid construction, easy availability and better fire rating are some of inherent advantages of steel construction. In current modern world, steel structure contributes a highest number of industrial buildings and sheds in the world building inventory. Pre-Engineered Building concept involves the steel building systems which are predesigned and prefabricated. This particular study includes the design of industrial storage structure which is situated in Man galore. The actual structure is of pre-engineered structure of 90m width of three spans each span 30m width, and running 42m length and of eave height 6m with roof slope 1:10. The analysis and design is carried out by considering the live loads, dead loads, wind loads and earthquake load using relevant IS codes for the given PEB structure. The whole Pre-engineered building and Conventional steel structure is analyzed by using staad pro V8i SS6 software and designed by limit state method as per IS 800-2007. The moment, shear force and axial force decreases in PEB structure in various components as compared to CSB structure, due to increase in stiffness. Deformation decreases in PEB structure in various components as compared to CSB structure, due to increase in stiffness. Base shear and displace ment decreases in PEB structure as compared to CSB structure, due to increase in stiffness. The percentage decrease in weight in PEB structure is 16.28% in comparison to CSB structure, hence cost of PEB structure reduces. Reduction in steel quantity reduces the dead load ultimately reduces the size of the foundation.

Bioefficacy of some plants ethanolic extracts against maize weevil (Sitophilus zeamais) infestation of stored maize grains

The experiment was conducted to determine the efficacy of three plants ethanolic extracts against maize weevil (Sitophilus zeamais) on stored maize grains (Zea mays). Five different ethanolic concentrations (0.5 mg/L, 1.0 mg/L, 2.0 mg/L, 4.0 mg/L and 8.0 mg/L) were made from the leaves of Hyptis suaveolens, Alstonia boonei and Tephrosia vogelii with 0.0 mg/L as the control (ethanol) and applied onto the maize grains by dipping. Theexperiment consists of six treatments (including control) and was laid in completely randomized design (CRD) with three replications. Data were collected for adult mortality, number of eggs, larval development and percentage grain damage. The data were subjected to analysis of variance (ANOVA) at 5% probability level with Duncan's Multiple Range Test (DMRT) used to separate the means that were significant. The result obtainedrevealed significant difference (P≤ 0.05) between the concentrations over the control in terms of toxicity, oviposition, induced adult mortality and progeny suppression. However, the extracts from Tephrosia vogelii are the most toxic and produced the best effect with LC of 4.85 mg/L at 24 hours of exposure and 1.94 mg/L at 48 50 hours of exposure. Similar result was found in terms of adult mortality and oviposition suppression. The effectof the extracts is concentration-dependent increase with increase in concentration. The percentage decrease in weight due to the weevil's infestation was found to be reduced with increase in concentrations. Thus, 8.0 mg/L of the ethanolic extracts of Tephrosia vogelii is recommended for biological control of Sitophilus zeamais against stored maize grains.
 Key Words: Concentrations, Ethanolic Extracts, Maize, Weevil.

Seasonal weight changes in laboratory ferrets.

Ferrets (Mustela putorius furo) are a valuable animal model used in biomedical research. Like many animals, ferrets undergo significant variation in body weight seasonally, affected by photoperiod, and these variations complicate the use weight as an indicator of health status. To overcome this requires a better understanding of these seasonal weight changes. We provide a normative weight data set for the female ferret accounting for seasonal changes, and also investigate the effect of fluid regulation on weight change. Female ferrets (n = 39) underwent behavioural testing from May 2017 to August 2019 and were weighed daily, while housed in an animal care facility with controlled light exposure. In the winter (October to March), animals experienced 10 hours of light and 14 hours of dark, while in summer (March to October), this contingency was reversed. Individual animals varied in their body weight from approximately 700 to 1200 g. However, weights fluctuated with light cycle, with animals losing weight in summer, and gaining weight in winter such that they fluctuated between approximately 80% and 120% of their long-term average. Ferrets were weighed as part of their health assessment while experiencing water regulation for behavioural training. Water regulation superimposed additional weight changes on these seasonal fluctuations, with weight loss during the 5-day water regulation period being greater in summer than winter. Analysing the data with a Generalised Linear Model confirmed that the percentage decrease in weight per week was relatively constant throughout the summer months, while the percentage increase in body weight per week in winter decreased through the season. Finally, we noted that the timing of oestrus was reliably triggered by the increase in day length in spring. These data establish a normative benchmark for seasonal weight variation in female ferrets that can be incorporated into the health assessment of an animal’s condition.

Phytochemistry and antidiabetogenic property of aqueous extract of Azadirachta indica leaf in streptozotocin-induced diabetic rats

Aim: This study was carried out to determine the phytochemicals and the antidiabetogenic property of Azadirachta indica leaf in streptozotocin-induced diabetic male rats. Methodology: The quantitative phytochemical analysis and the glucose levels were checked using standard methods. Different group of rats were pre-treated for seven, fourteen, twenty-one and twenty-eight days before the induction of diabetes to know the extent of protection the extract will have on the rats by preventing the onset of diabetes. At the end of each treatment period diabetes was induced intraperitoneally using 50mg/kg bodyweight of Streptozotocin. Results: The percentage composition of the phytochemicals in the leaves of Azadirachta indica was as follows: Alkaloids (11.36%), cardiac glycosides (6.19%), flavonoid (5.34%), heamaglutinin (6.331%), oxalate (0.0204%), phenol (4.312%), phytate (4.600%), saponin (12.55%), steroid (0.2566) and tannin (6.17%). The result obtained revealed that there was a better protection for the group of rats pretreated for a period of three weeks and four weeks. The percentage decrease in weight after the induction of diabetes for the groups pre-treated for a period of twenty-one days at varying doses of 100, 200 and 400 mg/kg bodyweight was 6.67%, 6.05% and 4.69% respectively which was significantly (p<0.05) different from the normal untreated group (9.90%). The percentage decrease in weight after the induction of diabetes for the groups pre-treated for a period of twenty-one days at varying doses of 100, 200 and 400 mg/kg bw is 7.04%, 5.97% and 2.50% respectively which was significantly (p<0.05) different from the normal untreated group (10.8%). The percentage increase in the fasting blood glucose level for the groups pretreated for a period of twenty-one days at varying doses of 100, 200 and 400 mg/kg bw was 65.4%, 76.3% and 72.4% respectively which is significantly (p<0.05) different from that of the normal untreated group (82.7%) and the group pre-treated with metformin at a dose of 100 mg/kg bw (84.5%). The percentage increase in the fasting blood glucose level for the groups pre-treated for a period of twenty-eight days at varying doses of 100, 200 and 400 mg/kg bw was 73.5%, 68.5% and 64.4% respectively which was significantly (p<0.05) different from that of the normal untreated group (83.3%) and the group pre-treated with metformin at a dose of 100 mg/kg bw (85.5%). The longer the period of pre-treatment, the better the reduction in the blood glucose levels recorded after the induction of diabetes. Conclusion: These results suggest that the aqueous extract of A. indica leaf has antidiabetogenic effect and could be used in the prevention as well as delaying the onset of diabetes mellitus.

EXPERIMENTAL INVESTIGATIONS ON THE INFLUENCE OF TiC/GRAPHITE REINFORCEMENT IN WEAR BEHAVIOR OF Al 6061HYBRID COMPOSITES

This research work focuses about fabrication and investigation on the influence of Titanium Carbide (TiC)-graphite particles reinforcement in wear behavior of Aluminium Matrix Composites (AMC). The stir casting technique was used to fabricate AMC reinforced with various weight percentage of TiC and graphite particles. Wear tests were conducted by using pin-on-disc wear testing machine. The hardness of the hybrid composites were recorded on the test specimen. The worn out surfaces of composites were analyzed using Scanning Electron Microscope (SEM). Results reveal that the presence of TiC and graphite particles improved the wear resistance. The wear of composite is primarily due to delamination and abrasion. The graphite particles serve as the solid lubricant on the wear of composite. The hardness of composite is improved with the decrease in weight percentage of graphite. SEM images reveal that the reinforcement particles in the matrix are homogeneously distributed. Also, worn-out surfaces of the composite were studied to observe wear track and wear mechanisms like plowing grooves, crack or cutting, and fragmentation.

S100A9 induces nociceptive pain but is not involved in allodynia in acute experimental synovitis

Purpose: Synovitis-associated pain is an important aspect of arthritis pathology. Several inflammatory mediators released by the synovium have been implicated in the regulation of pain, including S100A8 and S100A9 which may regulate pain either via direct stimulation of TLR4 on the nerve endings in the synovium or via stimulation at the site of the dorsal root ganglia (DRG), thereby enabling an increased phagocyte infiltration, which may cause sensitization. We aimed to elucidate the role of S100A9 in the pain response after induction of an acute synovitis using streptococcal cell walls (SCW) as a trigger, comparing S100A9-/- mice and their WT controls. Methods: Synovial biopsies of 25 patients with early symptomatic OA were studied by micro-array analysis and subsequent functional annotation clustering (FAC). Patients with pain at t=5 years after biopsy isolation according to WOMAC score, were compared to those without pain. Acute synovitis was induced by a single i.a. injection of SCW in the knee joint of C57Bl6 (WT) mice and S100A9-/- mice, control mice received an i.a. saline injection. Serum S100A8/A9 levels were investigated by ELISA and expression of S100A8 and S100A9 in synovium and DRG by immunohistochemistry. Joint swelling and cell influx was assessed by 99mTc accumulaiton and histology, respectively. Pain response were investigated Incapacitance Tester (weight bearing), Catwalk (gait analysis) and von Frey’s filaments (mechanical allodynia). Gene expression of inflammatory mediators and neuron activation markers in DRG were determined by q-PCR. Monocyte influx and protein expression of NAV1.7 and GAP43 was monitored by immunohistochemistry. Results: In synovial biopsies of early symptomatic OA patients, approximately 750 genes were upregulated in patients that had pain 5 years after inclusion compared to patients without pain. Functional annotation clustering showed that inflammatory genes were highly significantly enriched (p=6,4*10-12). Among the upregulated genes were the alarmins S100A8 and S100A9. In mice, a single i.a. injection of SCW resulted in increased synovial expression of S100A8 and S100A9 and subsequent increased serum S100A8/A9 levels (2.6-fold, P < 0.001) 1 day p.i., which returned to basal levels at 7 days p.i. The increased expression of S100A9 did not contribute to the development of inflammation since joint swelling and cell influx were similar in WT and S100A9-/- mice 1 day p.i. Using the Incapacitance Tester, WT mice showed a marked and significant decrease in percentage of weight bearing on the SCW injected hindpaw (28%) compared to saline injection (47%, P < 0.001) 1 day p.i., whereas S100A9-/- mice did not. In addition, gait analysis showed that the stand-phase of the unaffected paws were significantly increased in WT mice 1 day p.i., which will reduce the load on the inflamed paw, while in S100A9-/- mice these parameters were not altered. No difference in mechanical allodynia was observed, both mouse strains showed a similar reduction of paw withdrawal threshold (4.2 and 4.5 fold decrease respectively). Analysis of DRG showed no increased phagocyte infiltration after SCW injection as determined by S100A8 and S100A9 immunohistochemistry and no change in gene expression of MCP-1, KC, IL-1β or TNF was measured. In addition, nu change in F4/80 staining was seen in both WT and S100A9-/- mice. However, expression of neuron activation markers NAV1.7, ATF3 and GAP43 were significantly increased at 1 day after SCW injection in WT mice as compared to saline injected mice (P = 0.022, 0.004 and 0.030, respectively) while SCW injection in S100A9-/- mice did not show increased expression, which is in line in with the reduced pain response observed earlier in S100A9-/- mice. Immunohistochemically the difference in NAV1.7 expression in the DRG was further confirmed at protein level. Conclusions: These findings show that S100A9, which is released from the synovium upon inflammation, is an important mediator of inflammatory nociceptive pain response in the knee, rather than by being involved in peripheral sensitization. During the acute phase of inflammation S100A8/A9 is likely regulated via direct activation of TLR4 on nerve endings in the synovium and not via increased infiltration of phagocytes in the DRG.

Improved magnetoelectric effect in ytterbium doped BaTiO3 –CoFe2O4 particulate multiferroic composites

The quest for multiferroic materials, where the phenomena of ferroelectricity and ferromagnetism are intimately coupled, is of great technological and fundamental importance. In this work, multiferroic particulate composites, (1-x) Ba0.95Yb0.05TiO3-xCoYb0.1Fe1.9O4 (x = 0.3, 0.6 and 0.9), were prepared by the solid-state reaction method. In all the composites, lattice parameters of CoYb0.1Fe1.9O4 phase decrease with the decrease in weight percentage of Ba0.95Yb0.05TiO3 phase. This effect resulted in an increase in the density and magnetoelectric effect of the composites. The dielectric loss and conductivity of composites was minimized, and a drop in Curie temperature was observed by doping ytterbium in the individual phases. The Austin-Mott model predicts that the conductivity can be attributed to the small range polaron hopping. The Mott conductivity dominates at low temperatures and disturbs the domain structure resulting in unsaturated P-E loops. The Law of approach was adopted to calculate the magnetocrystalline anisotropy, as all the composites were multidomain structured. The incorporation of ytterbium increased the magnetostriction in CoFe2O4 phase which results in an increase in magnetocapacitance of all the composites.

Investigation of Heavy Organics Precipitation from Nigerian Crude Oil Residue Using Binary Mixture of n-Alkane Solvents

The effects of mixing two n-alkane solvents on the precipitation of heavy organics in crude oil were carried out. The crude oil sample sourced from a major operative in Nigeria was distilled at 240 o C and used for the precipitation experiment. The binary mixture of n-alkane solvents (C 6 : C 10 , C 6 : C 16 , C 10 : C 14 , C 10 : C 16 , C 14 : C 16 ) was carried out in the solvent ratio of 0:1, 1:2, 1:1, 2:1, and 1:0 respectively. From the results, C6: C10 mixture shows an abrupt decrease in heavy organics precipitated from 1:0 volume ratio of C 6 : C 10 to 2:1 volume ratio of C 6 : C 10 and a further steady decrease were observed. The percentage volume increment of C6 in the mixture of C 6 : C 16 , also shows steady and an abrupt decrease in heavy organics precipitated, which indicates phase transitions occurring at 1:1 and 2:1 volume ratio points. The additions of C 10 to C 14 and C 10 to C 16 results to decrease in the weight percentage of heavy organics precipitated. While a slight decrease in weight percentage of heavy organics occurs during the addition of C 14 to C 16 . Precipitation experiment carried out using binary mixture shows a three-stage phase transition: solid-liquid, liquid-solid and solid-liquid in C 6 : C 16 at different volume ratios of the mixtures. Keywords : Binary mixture, heavy organics, crude oil residue, n-alkane solvents, precipitates

Impact of holmium laser settings and fiber diameter on stone fragmentation and endoscope deflection.

We compared the impact of various energy settings, frequency, and fiber diameters on the stone fragmentation capabilities of the holmium laser. Stone phantoms, made from plaster of Paris and uniform in weight, were treated with one of two laser fiber sizes: small (200 and 365 microm) and large (550 and 1000 microm). Stones were immersed in water and fragmented for 3 minutes at 0.5, 1.0, or 2.0 J and 5, 10, or 15 Hz. The mean percentage decrease in weight in the two groups was compared using one-way ANOVA. The effect on flexible ureterorenoscope deflection of the small fibers was tested in two different ureterorenoscopes. Raising the energy level when using the small fibers resulted in more weight loss (P < 0.05). Increasing the frequency up to 10 Hz also resulted in a significant increase in weight loss (P < 0.05), yet above 10 Hz, there was no significant additional weight loss noted for either small fiber. There was no significant difference in the weight loss produced by the two fibers unless the energy setting was >1.0 J. Studies with the large fibers demonstrated similar results, with significant increments of weight loss occurring with increased energy (P < 0.05), while nonsignificant differences were seen for the two fiber diameters. Increasing laser frequency up to 15 Hz resulted in a significant increase in weight loss for the large fibers. Loss of ureterorenoscope deflection ranged from 7% to 16% and 18% to 37% for the 200-microm and 365-microm fibers, respectively. Small-diameter fibers, in combination with semirigid or flexible ureteroscopes, should be used to treat upper urinary tract stones. The 365-microm fiber should be utilized for the management of ureteral stones, as minimal endoscopic deflection is required to access these calculi. Because the 200-microm fibers are considerably more expensive, their use should be reserved for fragmentation of intrarenal calculi, where maximum deflection is required during flexible ureterorenoscopy. The ideal energy and frequency settings for the small fibers are <1.0 J and 5 to 10 Hz. Larger fibers can be used for managing bladder or renal calculi, as there is no need for significant fiber deflection. The 550-microm fiber is preferred, as it is comparable in efficacy to the 1000-microm fiber and is less expensive. Energy and frequency can be maximized to 2.0 J and 15 Hz without damage to the fiber, but visibility can be affected by high frequencies. Appropriate fiber selection and energy/frequency settings will allow access to most stones throughout the urinary tract, maximize fiber life, and minimize fiber expense.