Vector Dominance with Threshold Searchable Encryption (VDTSE) for the Internet of Things

The Internet of Medical Things(IoMT)is an application of the Internet of Things(IoT)in the medical field.It is a cutting-edge technique that connects medical sensors and their applications to healthcare systems,which is essential in smart healthcare.However,Personal Health Records(PHRs)are normally kept in public cloud servers controlled by IoMT service providers,so privacy and security incidents may be frequent.Fortunately,Searchable Encryption(SE),which can be used to execute queries on encrypted data,can address the issue above.Nevertheless,most existing SE schemes cannot solve the vector dominance threshold problem.In response to this,we present a SE scheme called Vector Dominance with Threshold Searchable Encryption(VDTSE)in this study.We use a Lagrangian polynomial technique and convert the vector dominance threshold problem into a constraint that the number of two equal-length vectors’corresponding bits excluding wildcards is not less than a threshold t.Then,we solve the problem using the proposed technique modified in Hidden Vector Encryption(HVE).This technique makes the trapdoor size linear to the number of attributes and thus much smaller than that of other similar SE schemes.A rigorous experimental analysis of a specific application for privacy-preserving diabetes demonstrates the feasibility of the proposed VDTSE scheme.

Influence of climate warming and nitrogen deposition on soil phosphorus composition and phosphorus availability in a temperate grassland,China

Climate warming and nitrogen （N） deposition change ecosystem processes, structure, and functioning whereas the phosphorus （P） composition and availability directly influence the ecosystem structure under condi- tions of N deposition. In our study, four treatments were designed, including a control, diurnal warming （DW）, N deposition （ND）, and combined warming and N deposition （WN）. The effects of DW, ND, and WN on P composition were studied by 3~p nuclear magnetic resonance （3~p NMR） spectroscopy in a temperate grassland region of China. The results showed that the N deposition decreased the soil pH and total N （TN） concentration but increased the soil OIsen-P concentration. The solution-state 31p NMR analysis showed that the DW, ND and WN treatments slightly decreased the proportion of orthophosphate and increased that of the monoesters. An absence of myo-inositol phosphate in the DW, ND and WN treatments was observed compared with the control. Furthermore, the DW, ND and WN treatments significantly decreased the recovery of soil P in the NaOH-EDTA solution by 17%-20%. The principal component analysis found that the soil pH was positively correlated with the P recovery in the NaOH-EDTA solution. Therefore, the decreased soil P recovery in the DW and ND treatments might be caused by an indirect influence on the soil pH. Additionally, the soil moisture content was the key factor limiting the available P. The positive correlation of total carbon （TC） and TN with the soil P composition indicated the influence of climate warming and N deposition on the biological processes in the soil P cycling.

Steam reforming of acetic acid over Ni-Ba/Al2O3 catalysts:Impacts of barium addition on coking behaviors and formation of reaction intermediates

The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were investigated in this study.The results showed the drastic effects of barium addition on the physicochemical properties and performances of the catalyst.The solid-phase reaction between alumina and BaO formed BaAl2O4,which re-constructed the alumina structure,resulting in a decrease in the specific surface area and an increase in the resistance of metallic Ni to sintering.The addition of barium was also beneficial for enhancing the catalytic activity,resulting from the changed catalytic reaction network.The in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study of the acetic acid steam reforming indicated that barium could effectively suppress the accumulation of the reaction intermediates of carbonyl,formate,and C=C functional groups on the catalyst surface,attributed to its relatively high ability to cause the gasification of these species.In addition,coking was considerably more significant over the Ba-Ni/Al2O3 catalyst.Moreover,the Ba-Ni/Al2O3 catalyst was more stable than the Ni/Al2O3catalyst,owing to the distinct forms of coke formed (carbon nanotube form over the Ba-Ni/Al2O3 catalyst,and the amorphous form over the Ni/Al2O3 catalyst).

OsABA8ox2, an ABA catabolic gene, suppresses root elongation of rice seedlings and contributes to drought response

In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of OsABA8ox2 in root growth and development and drought response. GUS staining results showed that OsABA8ox2 was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was markedly decreased after 0.5 h polyethylene glycol(PEG) treatment and increased after 0.5 h rehydration, implying that OsABA8ox2 is a drought-responsive gene.OsABA8ox2 knockout mediated by the CRISPR-Cas9 system increased drought-induced ABA and indole-3-acetic acid accumulation in roots, conferred increased ABA sensitivity, and promoted a more vertically oriented root system architecture(RSA) beneficial to drought tolerance.OsABA8ox2 overexpression suppressed root elongation and increased stomatal conductance and transpiration rate. Consequently, OsABA8ox2 knockout dramatically improved rice drought tolerance, whereas OsABA8ox2 overexpression seedlings were hypersensitive to drought stress,suggesting that OsABA8ox2 contributes to drought response in rice. Compared with wild type,functional leaves of OsABA8ox2 knockout seedlings showed higher ABA levels, whereas overexpression lines showed lower ABA levels, suggesting that OsABA8ox2, as an ABA catabolic gene, modulates ABA concentration through ABA catabolism. OsABA8ox2 and OsABA8ox3 were both localized in the endoplasmic reticulum. Together, these results indicate that OsABA8ox2 suppresses root elongation of rice seedlings, increases water transpiration, and contributes to drought response through ABA catabolism, and that OsABA8ox2 knockout dramatically improves rice drought tolerance. They highlight the key role of ABA catabolism mediated by OsABA8ox2 on root growth and development. OsABA8ox2, as a novel RSA gene, would be a potential genetic target for the improvement of rice drought tolerance.

Direct Growth of Graphene on Silicon by Metal-Free Chemical Vapor Deposition

The metal-free synthesis of graphene on singlecrystal silicon substrates, the most common commercial semiconductor, is of paramount significance for many technological applications. In this work, we report the growth of graphene directly on an upside-down placed,single-crystal silicon substrate using metal-free, ambientpressure chemical vapor deposition. By controlling the growth temperature, in-plane propagation, edge-propagation, and core-propagation, the process of graphene growth on silicon can be identified. This process produces atomically flat monolayer or bilayer graphene domains, concave bilayer graphene domains, and bulging few-layer graphene domains. This work would be a significant step toward the synthesis of large-area and layer-controlled, high-quality graphene on single-crystal silicon substrates.

The summertime circulation of the Bohai Sea simulated from a high-resolution wave-tide-circulation coupled model

The Bohai Sea is a shallow semi-enclosed inner sea with an average depth of 18 m and is located at the west of the northern Yellow Sea. The climatological circulation pattern in summer of the Bohai Sea is studied by using a wave-tide-circulation coupled model. The simulated temperature and the circulation agree with the observation well. The result shows that the circulation pattern of the Bohai Sea is jointly influenced by the tidal residual current, wind and baroclinic current. There exists an obvious density current along the temperature front from the west part of the Liaodong Bay to the offshore area of the Huanghe Estuary. In the Liaodong Bay there exists a clockwise gyre in the area north to the 40°N. While in the area south to the 40°N the circulation shows a two-gyre structure, the flow from the offshore area of the Huanghe Estuary to the Liaodong Bay splits into two branches in the area between 39°N and 40°N. The west branch turns into north-west and forms an anti-clockwise gyre with the south-westward density current off the west of the Liaodong Bay. The east branch turns to the east and forms a clockwise gyre with the flow along the east coast of the Liaodong Bay. The forming mechanism of the circulation is also discussed in this paper.

Resolving Mixed Intermediate Phases in Methylammonium-Free Sn-Pb Alloyed Perovskites for High-Performance Solar Cells

The complete elimination of methylammonium(MA)cations in Sn-Pb composites can extend their light and thermal stabilities.Unfortunately,MA-free Sn-Pb alloyed perovskite thin films suffer from wrinkled surfaces and poor crystallization,due to the coexistence of mixed intermediate phases.Here,we report an additive strategy for finely regulating the impurities in the intermediate phase of Cs_(0.25)FA_(0.75)Pb_(0.6)Sn_(0.4)I_(3)and,thereby,obtaining high-performance solar cells.We introduced d-homoserine lactone hydrochloride(D-HLH)to form hydrogen bonds and strong Pb-O/Sn-O bonds with perovskite precursors,thereby weakening the incomplete complexation effect between polar aprotic solvents(e.g.,DMSO)and organic(FAI)or inorganic(CsI,PbI_(2),and SnI_(2))components,and balancing their nucleation processes.This treatment completely transformed mixed intermediate phases into pure preformed perovskite nuclei prior to thermal anneal-ing.Besides,this D-HLH substantially inhibited the oxidation of Sn^(2+) species.This strategy generated a record efficiency of 21.61%,with a Voc of 0.88 V for an MA-free Sn-Pb device,and an efficiency of 23.82%for its tandem device.The unencapsulated devices displayed impressive thermal stability at 85℃ for 300 h and much improved continuous operation stability at MPP for 120 h.

Detection of Cracks in Aerospace Turbine Disks Using an Ultrasonic Phased Array C-scan Device

Crack detection in an aerospace turbine disk is essential for aircraft-quality detection.With the unique circular stepped structure and superalloy material properties of aerospace turbine disk,it is difficult for the traditional ultrasonic testing method to perform efficient and accurate testing.In this study,ultrasound phased array detection technology was applied to the non-destructive testing of aviation turbine disks:(i)A phased array ultrasonic c-scan device for detecting aerospace turbine disk cracks(PAUDA)was developed which consists of phased array ultrasonic,transducers,a computer,a displacement encoder,and a rotating scanner;(ii)The influence of the detection parameters include frequency,wave-type,and elements number of the ultrasonic phased array probe on the detection results on the near-surface and the far surface of the aerospace turbine disk is analyzed;(iii)Specimens with flat-bottom-hole(FBH)defects were scanned by the developed PAUDA and the results were analyzed and compared with the conventional single probe ultrasonic water immersion testing.The experiment shows that by using the ultrasonic phased array c-scan to scan the turbine disk the accuracy of the detection can be significantly improved which is of greater accuracy and higher efficiency than traditional immersion testing.

RNA m^(6)A reader YTHDF2 facilitates precursor miR-126 maturation to promote acute myeloid leukemia progression

As the most common internal modification of mRNA,Ne-methyladenosine(m^(6)A)and its regulators modulate gene expression and play critical roles in various biological and patholog-ical processes including tumorigenesis.It was reported previously that m^(6)A methyltransferase(writer),methyltransferase-like 3(METTL3)adds m^(6)A in primary microRNAs(pri-miRNAs)and fa-cilitates its processing into precursor miRNAs(pre-miRNAs).However,it is unknown whether m^(6)A modification also plays a role in the maturation process of pre-miRNAs and(if so)whether such a function contributes to tumorigenesis.Here,we found that YTHDF2 is aberrantly overexpressed in acute myeloid leukemia(AML)patients,especially in relapsed patients,and plays an onco-genic role in AML.Moreover,YTHDF2 promotes expression of miR-126-3p(also known as miR-126,as it is the main product of precursor miR-126(pre-miR-126)),a miRNA that was reported as an oncomiRNA in AML,through facilitating the processing of pre-miR-126 into mature miR-126.Mechanistically,YTHDF2 recognizes m^(6)A modification in pre-miR-126 and recruits AGO2,a regulator of pre-miRNA processing,to promote the maturation of pre-miR-126.YTHDF2 posi-tively and negatively correlates with miR-126 and miR-126's downstream target genes,respec-tively,in AML patients,and forced expression of miR-126 could largely rescue YTHDF2/Ythdf2 depletion-mediated suppression on AML cell growth/proliferation and leukemogenesis,indi-cating that miR-126 is a functionally important target of YTHDF2 in AML.Overall,our studies not only reveal a previously unappreciated YTHDF2/miR-126 axis in AML and highlight the ther-apeutic potential of targeting this axis for AML treatment,but also suggest that m^(6)A plays a role in pre-miRNA processing that contributes to tumorigenesis.

Application of wastewater-based epidemiological monitoring of COVID-19 for disease surveillance in the city

Wastewater-based surveillance serves as a supplementary approach to clinical surveillance of COVID-19 during the epidemic.This study aimed to track the prevalence of the disease and the viral genetic variability through wastewater-based surveillance in the post-epidemic era.Between January to December 2023,samples were collected from the influent lines of two wastewater treatment plants(WWTPs),concentrated using PEG8000,and subjected to detection of the target genes ORF 1ab and N of SARS-CoV-2 via reverse transcriptional quantitative PCR(RT-qPCR).For next-generation sequencing(NGS),high-quality samples from both wastewater and clinical patients were selected.Weekly analysis were performed using R software to evaluate the correlation between the SARSCoV-2 RNA concentrations in wastewater and positive rate of reported cases,indicating a positive correlation.Genetic diversity patterns of SARS-CoV-2 in wastewater resembled those in the patient source based on Principal Coordinates Analysis(PCoA)with three clusters for different stages.The rise of RNA concentration in wastewater indicates the growth of cases and the emergence of new variants,serving as an early warning of potential viral mutations,disease outbreaks even possible epidemics.Furthermore,the genomic surveillance of wastewater could help identify new variants that may not be captured through population monitoring,especially when sample sizes are insufficient.Consequently,surveillance of SARS-CoV-2 in municipal wastewater has emerged as a reliable,earlywarning monitoring system for COVID-19 in the post-epidemic era.

Preparation of baicalin colon-targeted granules and its intervention effect on ulcerative colitis in rats

Baicalin(BA)is a flavonoid extracted from the dried root of Scutellaria baicalensis Georgi with excellent antioxidant and anti-inflammatory biological activities.In this study,Eudragit S100 was used as the colonic target material to prepare BA colonic targeting granules(EBCGs)based on plasticizer dry powder coating technology to improve the targeting transportation performance of BA.In vitro studies showed that EBCGs with pH-sensitive properties were successfully prepared by plasticizer dry powder coating,and in vivo animal imaging studies showed that EBCGs could deliver BA to the colon and inhibit the release of BA in the upper gastrointestinal tract(GIT).In vivo studies showed that EBCGs had good therapeutic effects in colitis,which reduced expression levels of tumor necrosis factor alpha(TNF-α)and interleukin-1β(IL-1β)and increased superoxide dismutase(SOD)activities in the colonic tissues of rats with colitis.In conclusion,Eudragit S100 could be used for the preparation of multi-unit oral colon-targeted formulations by plasticizer dry powder coating technology,and our prepared EBCGs had good colon-targeting properties,which could improve the therapeutic effect and provide a potential application for ulcerative colitis(UC).

Performance enhancement in organic solar cells and photodetectors enabled by donor phase optimization at the surface of hole transport layer

The domain purity,material crystallinity and distribution at the interface between the active layer and the transport layer have an important impact on the performance of organic solar cells(OSCs)and organic photodetectors(OPDs),while this focal issue has received less attention in previous studies.From this perspective,a new method to simultaneously enhance the performance of OSC and OPD is proposed,namely,using a sequential deposition method to first construct a compact stacking structure of dualdonor(D18-Cl:PTO2)eutectic in the donor layer,and then induce the ordered deposition of the acceptor(Y6).Compared with the conventional bulk heterojunction(BHJ),the active layer realized by this method not only improves the crystallinity and stacking order of the constituent material on the surface of the transport layer,but also regulates a good vertical distribution,which is conducive to improving the charge transport and extraction efficiency,reducing the leakage current,and enhancing the stability of the device.As a result,the OSC device based on the D18-Cl:PTO2/Y6 structure achieves a power conversion efficiency of up to 17.65%and good light-degradation stability,which is much better than that of BHJbased OSC(PCE of 16.37%).For the OPD,the dark current at reverse bias is reduced by more than an order of magnitude,and the maximum responsivity is improved to 0.52 A/W through the optimization of the donor phase at the interface.Moreover,the strategy does not require additional post-processing compared to the BHJ preparation,which reduces the device construction cost and process complexity,providing an effective way for developing high-performance organic optoelectronic devices.

Modified Multi-Key Fully Homomorphic Encryption Based on NTRU Cryptosystem without Key-Switching

The Multi-Key Fully Homomorphic Encryption (MKFHE) based on the NTRU cryptosystem is an important alternative to the post-quantum cryptography due to its simple scheme form,high efficiency,and fewer ciphertexts and keys.In 2012,Lopez-Alt et al.proposed the first NTRU-type MKFHE scheme,the LTV12 scheme,using the key-switching and modulus-reduction techniques,whose security relies on two assumptions:the Ring Learning With Error (RLWE) assumption and the Decisional Small Polynomial Ratio (DSPR) assumption.However,the LTV12and subsequent NTRU-type schemes are restricted to the family of power-of-2 cyclotomic rings,which may affect the security in the case of subfield attacks.Moreover,the key-switching technique of the LTV12 scheme requires a circular application of evaluation keys,which causes rapid growth of the error and thus affects the circuit depth.In this paper,an NTRU-type MKFHE scheme over prime cyclotomic rings without key-switching is proposed,which has the potential to resist the subfield attack and decrease the error exponentially during the homomorphic evaluating process.First,based on the RLWE and DSPR assumptions over the prime cyclotomic rings,a detailed analysis of the factors affecting the error during the homomorphic evaluations in the LTV12 scheme is provided.Next,a Low Bit Discarded&Dimension Expansion of Ciphertexts (LBD&DEC) technique is proposed,and the inherent homomorphic multiplication decryption structure of the NTRU is proposed,which can eliminate the key-switching operation in the LTV12 scheme.Finally,a leveled NTRU-type MKFHE scheme is developed using the LBD&DEC and modulus-reduction techniques.The analysis shows that the proposed scheme compared to the LTV12 scheme can decrease the magnitude of the error exponentially and minimize the dimension of ciphertexts.

Removal of hexavalent chromium from contaminated waters by ultrasound-assisted aqueous solution ball milling

Batch mode experiments were conducted to study the removal of hexavalent chromium（Cr（Ⅵ）） from aqueous solutions using ultrasound-assisted aqueous solution ball milling.The results show that the reduction rate of Cr（Ⅵ） by ultrasound-assisted aqueous solution ball milling was significantly faster than that by ball milling or ultrasound treatment alone,and an initial Cr（Ⅵ） concentration of 166 mg/L could be decreased to 0.35 mg/L at 120 min.The decisive factors, including initial concentration of Cr（Ⅵ）, p H value, ultrasonic frequency and filling gas, were studied. It was found that the optimal ultrasonic frequency for ultrasound-assisted aqueous solution ball milling device was 20 k Hz, and the rate of Cr（Ⅵ）reduction as a function of filling gas followed the order： Ar 〉 air 〉 N2〉 O2. Samples were characterized by X-ray diffraction, fluorescence measurements, atomic absorption and the diphenylcarbazide colorimetric method. The Cr（Ⅵ） transformed into a precipitate that could be removed from the contaminated water, after which the water could be reused.

Promoting proliferation and differentiation of BMSCs by green tea polyphenols functionalized porous calcium phosphate

In this article,we proposed a facile protocol to functionalize porous calcium phosphate ceramics(PCPC)using dietary tea polyphenols(TP).TP molecules was attracted and anchored by Ca2t ions from the surface of CPC.These TP molecules modulated the nucleation and crystallization of calcium phosphate nanorods assemblies on the surface of PCPC.Our results prove that these calcium phosphate nanorods assemblies accompanies functional groups of TP make PCPC/TP effectively promote proliferation and differentiation of bone mesenchymal stem cells(BMSCs).We inferred that these calcium phosphate nanorods assemblies might change the surface microenvironment of PCPC,which is critical to promote the proliferation and differentiation of BMSCs.Compared with naked PCPC,PCPC/TP obviously increased BMP2,ErK/MAPK and JNK/MAPK level and mineralization capacity of cells(ALP level).

Electrospinning of antibacterial and anti-inflammatory Ag@hesperidin core-shell nanoparticles into nanofibers used for promoting infected wound healing

Bacterial infection and excessive inflammation are still the main obstacles to wound repair.Thus,antibacterial and antiinflammation nanomaterials are always attracting for infected wound healing.In this work,ultra-uniform(-20 nm)and colloidally stable Ag nanoparticles(Ag-Hes NPs)with core-shell structure were prepared by using hesperidin as reducing and capping agent.The obtained Ag-Hes NPs present effective antibacterial properties on both Staphylococcus aureus and Escherichia coli.Ag-Hes NPs also got high 1,1-diphenyl-1-picrylhydrazyl scavenging capability of 69%.Under the package of polyvinyl alcohol and sodium alginate,Ag-Hes NPs were encapsulated into electro spun nanofibers to form hydrogel(Ag-Hes@H).This strategy provides a moisture environment which could enrich and release Ag-Hes NPs gradually.Cell experiments and animal wound healing investigation proved that Ag-Hes@H could promote the proliferation and migration of human umbilical vein endothelial cells and accelerate infected wound healing.Meanwhile,Ag-Hes@H significantly reduced the expression of inflammatory cytokines,including IL-6,MMP9 and TNF-α.Immunohistochemistry data further suggested that Ag-Hes@H accelerated wound closure by promoting collagen deposition and skin cell proliferation.The designed antibacterial and anti-inflammatory Ag-Hes@H has great potential for promoting infected wound healing.

Repair calvarial defect of osteoporotic rats by berberine functionalized porous calcium phosphate scaffold

In this article,we propose a simple scheme of using berberine(BBR)to modify porous calcium phosphate ceramics(named PCPC).These BBR molecules regulate the crystallization of hydroxyapatite nanorods on PCPC.We found that these nanorods and the adsorbed BBR changed the interface micro-environment of PCPC by SEM images.The microenvironment of PCPC surface is essential for promoting BMSCs’proliferation and differentiation.These results demonstrated that PCPC/BBR markedly improved the bone regeneration of osteoporosis rats.Moreover,PCPC/BBR had significantly increased the expression levels of ALP,osteocalcin and bone morphogenetic protein2 and RUNX2 in BMSCs originated from osteoporosis rats.

Preparation of EGCG decorated,injectable extracellular vesicles for cartilage repair in rat arthritis

Arthritis is a kind of chronic inflammatory autoimmune disease,which can destroy joint cartilage and bone,leading to joint pain,joint swelling,and limited mobility.Traditional therapies have many side effects or focus too much on anti-inflammation while neglecting joint repair.In this experiment,we combined Epigallocatechin gallate(EGCG)with extracellular vesicles derived from macrophages to treat rheumatoid arthritis.Sustained-release resulted in a significant decrease in chondrocyte expression of hypoxia-inducible factor 1-alpha,a decrease in apoptosis-related proteins Cytochrome C,Caspase-3,Caspase-9,and Bax.Molecular biological analysis showed that extracellular vesicles-encapsulated EGCG(EVs-EGCG)more significantly upregulated type II collagen expression by about 1.8-fold than EGCG alone,which was more beneficial for arthritis repair.Animal experiments revealed that these EGCG-coated extracellular vesicles significantly reduced swelling,decreased synovial hyperplasia,repaired cartilage,and attenuated arthritis-related pathology scores in arthritic rats.Measurement data showed that EVs-EGCG treatment reduced joint swelling by approximately 39.5%in rheumatoid rats.In vitro studies have shown that this EVs-EGCG can increase the expression of cartilage type II collagen and reduce apoptosis of chondrocytes.Moreover,it was demonstrated in vivo experiments to reduce cartilage destruction in rheumatoid arthritis rats,providing a solution for the treatment of rheumatoid arthritis.

Sensitivity of the half-life time of water exchange in coastal waters

A three-dimensional model was established to investigate water exchange in coastal waters, and applied to Qinzhou Bay(QZB) in the South China Sea. Given the strong tidal current in QZB, a half-life time was calculated for water exchange by filtering the tidal signal from the concentrations of a conservative substance. In a control run driven by the tide, without external inputs and an open boundary concentration of zero, it was estimated that the average half-life time in QZB was 54.8 d. Numerical experiments showed that wind accounted for an 11.9% reduction in the half-life time to 48.3 d. When rivers were included in the model, the half-life time decreased by 74.6% to 13.9 d. Sensitivity experiments showed that the half-life time for water exchange was greatly affected by the concentration of the conservative substance which was used at the open boundary. In response to 10,20, 30, and 40% increases in the boundary concentration, the half-life time increased to 91.5, 168.3, 186.2, and 229.1 d,respectively. Results also suggested that for coastal bays with large intertidal areas such as QZB, consideration of the wet and dry processes produced more accurate simulations of the hydrodynamics and the half-life times. Simulations, which did not incorporate wet and dry processes, were more than likely to have overestimated or underestimated the half-life times for water exchange.

Adjoint Method for an Inverse Problem of CCPF Model

The problem for determining the exchange rate function of 2D CCPF model by measurements on the partial boundary is considered and solved as one PDE-constraint optimization problem. The optimal variant is the minimum of a cost functional that quantifies the difference between the measurements and the exact solutions. Gradientbased algorithm is used to solve this optimization problem. At each step, the derivative of the cost functional with respect to the exchange rate function is calculated and only one forward solution and one adjoint solution are needed. One method based on the adjoint equation is developed and implemented. Numerical examples show the efficiency of the adjoint method.