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Thanks to its excellent climate and varied agroecological zones, Nepal has been a significant player in the global rose market. The geographical variety of the nation makes it possible to grow roses all year long, making it a desirable location for rose export and cultivation. The production and export of roses have significantly increased in recent years. The rose trade has increased in Nepal for several reasons. Investment in the industry has been stimulated by government measures to support floriculture and offer incentives to rose farmers. Additionally, the effective distribution of roses to domestic and foreign markets has been made possible by better transportation infrastructure. The growth of the global market has greatly aided the development of Nepal's rose industry. The growth of rose cultivation in Nepal has significantly impacted the economy and employment. It is a good source of revenue through internal sales, export, and other activities that provide value addition. The sector creates direct farm jobs while local communities benefit from indirect employment in supporting industries. In addition, there is increased job opportunities due to seasonal spikes in demand. Rose exports have expanded due to a rise in demand for Nepali roses, particularly in European markets and nearby nations like India. The favorable trade agreements Nepal has with several nations have helped to increase its exports even more. But issues still exist in the rose trade sector. Since maintaining consistent quality is necessary to compete in the international market, quality control and standardization continue to be areas of concern. The rose business in Nepal is also vulnerable to changes in global demand and competition from other nations that grow roses. Further expansion of the industry will help it overcome problems like limited technology and training hence leading to its fast development; this calls for government support as well as market expansion. In conclusion, the rose trade environment in Nepal is a fluid and changing one. Due to favorable circumstances, government assistance, and global demand, the sector has seen significant expansion. Continuous efforts in quality control, market diversification, and innovation are necessary to maintain and grow this sector. The rose trade in Nepal has the potential to significantly boost the nation's agricultural exports while promoting economic growth in rural areas., Competing Interests: 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., (© 2024 The Authors.)

Objective . Microdosimetry offers a fast tool for radiation quality (RQ) verification to be implemented in treatment planning systems in proton therapy based on variable LET or RBE to move forward from the use of a fixed RBE of 1.1. It is known that the RBE of protons can increase up to 50% higher than that value in the last few millimetres of their range. Microdosimetry can be performed both experimentally and by means of Monte Carlo (MC) simulations. This paper has the aim of comparing the two approaches. Approach . Experimental measurements have been performed using a miniaturized Tissue equivalent proportional counter developed at the Legnaro National Laboratories of the Italian National Institute for Nuclear Physics with the aim of being used as RQ monitors for high intensity beams. MC simulations have been performed using the microdosimetric extension of TOPAS which provides optimized parameters and scorers for this application. Main results . Simulations were compared with experimental microdosimetric spectra in terms of shape of the spectra and their average values. Moreover, the latter have been investigated as possible estimators of LET obtained with the same MC code. The shape of the spectra is in general consistent with the experimental distributions and the average values of the distributions in both cases can predict the RQ increase with depth. Significance . This study aims at the comparison of microdosimetric spectra obtained from both experimental measurements and the microdosimetric extension of TOPAS in the same radiation field., (© 2023 Institute of Physics and Engineering in Medicine.)

Measurements in the stray radiation field from a proton therapy pencil beam at energies 70 and 146 MeV were performed using microdosimetric tissue-equivalent proportional counters (TEPCs). The detector volumes were filled with a propane-based tissue-equivalent gas at low pressure simulating a mean chord length of 2 μm in tissue. Investigations were performed with and without a beam range shifter, and with different air gaps between the range shifter and a solid water phantom. The absorbed dose, the dose-mean lineal energy, and the dose equivalent were determined for different detector positions using the variance-covariance method. The influence from beam energy, detector- and range-shifter positions on absorbed dose, LET, and dose equivalent were investigated. Monte Carlo simulations of the fluence, detector response, and absorbed dose contribution from different particles were performed with MCNP 6.2. The simulated dose response for protons, neutrons, and photons were compared with, and showed good agreement with, previously published experimental data. The simulations also showed that the TEPC absorbed dose agrees well with the ambient absorbed dose for neutron energies above 20 MeV. The results illustrate that changes in both dose and LET variations in the stray radiation field can be identified from TEPC measurements using the variance-covariance method. The results are in line with the changes seen in the simulated relative dose contributions from different particles associated with different proton energies and range-shifter settings. It is shown that the proton contribution scattered directly from the range shifter dominates in some situations, and although the LET of the radiation is decreased, the ambient dose equivalent is increased up to a factor of 3., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Eliasson, Lillhök, Bäck, Billnert-Maróti, Dasu and Liszka.)

Microdosimetry is an important tool for assessing energy deposition distributions from ionizing radiation at cellular and cellular nucleus scales. It has served as an input parameter for multiple common mathematical models, including evaluation of relative biological effectiveness (RBE) of carbon ion therapy. The most common detector used for microdosimetry is the tissue-equivalent proportional counter (TEPC). Although it is widely applied, TEPC has various inherent uncertainties. Therefore, this work quantified the magnitude of TEPC measurement uncertainties and their impact on RBE estimates for therapeutic carbon beams. Microdosimetric spectra and frequency-, dose-, and saturation-corrected dose-mean lineal energy (****) were calculated using the Monte Carlo toolkit Geant4 for five monoenergetic and three spread-out Bragg peak carbon beams in water at every millimeter along the central beam axis. We simulated the following influences on these spectra from eight sources of uncertainty: wall effects, pulse pile-up, electronics, gas pressure, W-value, gain instability, low energy cut-off, and counting statistics. Statistic uncertainty was quantified as the standard deviation of perturbed values for each source. Bias was quantified as the difference between default lineal energy values and the mean of perturbed values for each systematic source. Uncertainties were propagated to RBE using the modified microdosimetric kinetic model (MKM). Variance introduced by statistic sources iny¯Fandy¯Daveraged 3.8% and 3.4%, respectively, and 1.5% iny*across beam depths and energies. Bias averaged 6.2% and 7.3% iny¯Fandy¯D,and 4.8% iny*.These uncertainties corresponded to 1.2 ± 0.9% on average in RBE MKM . The largest contributors to variance and bias were pulse pile-up and wall effects. This study established an error budget for microdosimetric carbon measurements by quantifying uncertainty inherent to TEPC measurements. It is necessary to understand how robust the measurement of RBE model input parameters are against this uncertainty in order to verify clinical model implementation., (© 2021 Institute of Physics and Engineering in Medicine.)

Purpose: To study the agreement between proton microdosimetric distributions measured with a silicon-based cylindrical microdosimeter and a previously published analytical microdosimetric model based on Geant4-DNA in-water Monte Carlo simulations for low energy proton beams., Methods and Material: Distributions for lineal energy ( y ) are measured for four proton monoenergetic beams with nominal energies from 2.0 MeV to 4.5 MeV, with a tissue equivalent proportional counter (TEPC) and a silicon-based microdosimeter. The actual energy for protons traversing the silicon-based microdosimeter is simulated with SRIM. Monoenergetic beams with these energies are simulated with Geant4-DNA code by simulating a water cylinder site of dimensions equal to those of the microdosimeter. The microdosimeter response is calibrated by using the distribution peaks obtained from the TEPC. Analytical calculations for y ¯ F and y ¯ D using our methodology based on spherical sites are also performed choosing the equivalent sphere to be checked against experimental results., Results: Distributions for y at silicon are converted into tissue equivalent and compared to the Geant4-DNA simulated, yielding maximum deviations of 1.03% for y ¯ F and 1.17% for y ¯ D . Our analytical method generates maximum deviations of 1.29% and 3.33%, respectively, with respect to experimental results., Conclusion: Simulations in Geant4-DNA with ideal cylindrical sites in liquid water produce similar results to the measurements in an actual silicon-based cylindrical microdosimeter properly calibrated. The found agreement suggests the possibility to experimentally verify the calculated clinical y ¯ D with our analytical method., Competing Interests: Declaration of interests 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.

Single ventricle heart defects (SVDs) are congenital disorders that result in a variety of complications, including increased ventricular mechanical strain and mixing of oxygenated and deoxygenated blood, leading to heart failure without surgical intervention. Corrective surgery for SVDs are traditionally handled by the Fontan procedure, requiring a vascular conduit for completion. Although effective, current conduits are limited by their inability to aid in pumping blood into the pulmonary circulation. In this report, we propose an innovative and versatile design strategy for a tissue engineered pulsatile conduit (TEPC) to aid circulation through the pulmonary system by producing contractile force. Several design strategies were tested for production of a functional TEPC. Ultimately, we found that porcine extracellular matrix (ECM)-based engineered heart tissue (EHT) composed of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and primary cardiac fibroblasts (HCF) wrapped around decellularized human umbilical artery (HUA) made an efficacious basal TEPC. Importantly, the TEPCs showed effective electrical and mechanical function. Initial pressure readings from our TEPC in vitro (0.68 mmHg) displayed efficient electrical conductivity enabling them to follow electrical pacing up to a 2 Hz frequency. This work represents a proof of principle study for our current TEPC design strategy. Refinement and optimization of this promising TEPC design will lay the groundwork for testing the construct's therapeutic potential in the future. Together this work represents a progressive step toward developing an improved treatment for SVD patients. STATEMENT OF SIGNIFICANCE: Single Ventricle Cardiac defects (SVD) are a form of congenital disorder with a morbid prognosis without surgical intervention. These patients are treated through the Fontan procedure which requires vascular conduits to complete. Fontan conduits have been traditionally made from stable or biodegradable materials with no pumping activity. Here, we propose a tissue engineered pulsatile conduit (TEPC) for use in Fontan circulation to alleviate excess strain in SVD patients. In contrast to previous strategies for making a pulsatile Fontan conduit, we employ a modular design strategy that allows for the optimization of each component individually to make a standalone tissue. This work sets the foundation for an in vitro, trainable human induced pluripotent stem cell based TEPC., (Copyright © 2019. Published by Elsevier Ltd.)

A new mini-TEPC with cylindrical sensitive volume of 0.9 mm in diameter and height, and with external diameter of 2.7 mm, has been developed to work without gas flow. With such a mini counter we have measured the physical quality of the 62 MeV therapeutic proton beam of CATANA (Catania, Italy). Measurements were performed at six precise positions along the Spread-Out Bragg Peak (SOBP): 1.4, 19.4, 24.6, 29.0, 29.7 and 30.8 mm, corresponding to positions of clinical relevance (entrance, proximal, central, and distal-edge of the SOBP) or of high lineal energy transfer (LET) increment (distal-dose drop off). Without refilling the microdosimeter with new gas, the measurements were repeated at the same positions 4 months later, in order to study the stability of the response in sealed-mode operation. From the microdosimetric spectra the frequency-mean lineal energy y- F and the dose-mean lineal energy y- D were derived and compared with average LET values calculated by means of Geant4 simulations. The comparison points out, in particular, a good agreement between microdosimetric y- D and the total dose-average LET¯ d , which is the average LET of the mixed radiation field, including the contribution by nuclear reactions., (Copyright © 2019 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

Radiation-induced bone diseases were frequently reported in radiotherapy patients. To study the diseases, microdosimeters were constructed with walls of A150-A150, A150-B100, B100-A150 and B100-B100 interfaces. Monte Carlo simulations of these microdosimeters were performed to determine the lineal energy spectra of an interface site at different depths in water for 230 MeV protons. Comparing these spectra with data of ICRU tissue and bone walls, better agreements were found at shallow depths for protons and delta-rays than deep depths for nuclear interactions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Purpose: To measure the environmental doses from stray neutrons in the vicinity of a solid slab phantom as a function of beam energy, field size and modulation width, using the proton pencil beam scanning (PBS) technique., Method: Measurements were carried out using two extended range WENDI-II rem-counters and three tissue equivalent proportional counters. Detectors were suitably placed at different distances around the RW3 slab phantom. Beam irradiation parameters were varied to cover the clinical ranges of proton beam energies (100-220MeV), field sizes ((2×2)-(20×20)cm 2 ) and modulation widths (0-15cm)., Results: For pristine proton peak irradiations, large variations of neutron H ∗ (10)/D were observed with changes in beam energy and field size, while these were less dependent on modulation widths. H ∗ (10)/D for pristine proton pencil beams varied between 0.04μSvGy -1 at beam energy 100MeV and a (2×2)cm 2 field at 2.25m distance and 90° angle with respect to the beam axis, and 72.3μSvGy -1 at beam energy 200MeV and a (20×20) cm 2 field at 1m distance along the beam axis., Conclusions: The obtained results will be useful in benchmarking Monte Carlo calculations of proton radiotherapy in PBS mode and in estimating the exposure to stray radiation of the patient. Such estimates may be facilitated by the obtained best-fitted simple analytical formulae relating the stray neutron doses at points of interest with beam irradiation parameters., (Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

The authors attempt to establish the relative biological effectiveness (RBE) calculation for designing therapeutic proton beams on the basis of microdosimetry. The tissue-equivalent proportional counter (TEPC) was used to measure microdosimetric lineal energy spectra for proton beams at various depths in a water phantom. An RBE-weighted absorbed dose is defined as an absorbed dose multiplied by an RBE for cell death of human salivary gland (HSG) tumor cells in this study. The RBE values were calculated by a modified microdosimetric kinetic model using the biological parameters for HSG tumor cells. The calculated RBE distributions showed a gradual increase to about 1cm short of a beam range and a steep increase around the beam range for both the mono-energetic and spread-out Bragg peak (SOBP) proton beams. The calculated RBE values were partially compared with a biological experiment in which the HSG tumor cells were irradiated by the SOBP beam except around the distal end. The RBE-weighted absorbed dose distribution for the SOBP beam was derived from the measured spectra for the mono-energetic beam by a mixing calculation, and it was confirmed that it agreed well with that directly derived from the microdosimetric spectra measured in the SOBP beam. The absorbed dose distributions to planarize the RBE-weighted absorbed dose were calculated in consideration of the RBE dependence on the prescribed absorbed dose and cellular radio-sensitivity. The results show that the microdosimetric measurement for the mono-energetic proton beam is also useful for designing RBE-weighted absorbed dose distributions for range-modulated proton beams.