The impacts of the quantum-dot confining potential on the spin-orbit effect

For a nanowire quantum dot with the confining potential modeled by both the infinite and the finite square wells, we obtain exactly the energy spectrum and the wave functions in the strong spin-orbit coupling regime. We find that regardless of how small the well height is, there are at least two bound states in the finite square well: one has the σ ^x [Formula: see text] = -1 symmetry and the other has the σ ^x [Formula: see text] = 1 symmetry. When the well height is slowly tuned from large to small, the position of the maximal probability density of the first excited state moves from the center to x ≠ 0, while the position of the maximal probability density of the ground state is always at the center. A strong enhancement of the spin-orbit effect is demonstrated by tuning the well height. In particular, there exists a critical height [Formula: see text], at which the spin-orbit effect is enhanced to maximal.

Peripheral cytokine and chemokine alterations in depression: a meta-analysis of 82 studies

OBJECTIVE

To conduct a systematic review and meta-analysis of studies that measured cytokine and chemokine levels in individuals with major depressive disorder (MDD) compared to healthy controls (HCs).

METHOD

The PubMed/MEDLINE, EMBASE, and PsycINFO databases were searched up until May 30, 2016. Effect sizes were estimated with random-effects models.

RESULT

Eighty-two studies comprising 3212 participants with MDD and 2798 HCs met inclusion criteria. Peripheral levels of interleukin-6 (IL-6), tumor necrosis factor (TNF)-alpha, IL-10, the soluble IL-2 receptor, C-C chemokine ligand 2, IL-13, IL-18, IL-12, the IL-1 receptor antagonist, and the soluble TNF receptor 2 were elevated in patients with MDD compared to HCs, whereas interferon-gamma levels were lower in MDD (Hedge's g = -0.477, P = 0.043). Levels of IL-1β, IL-2, IL-4, IL-8, the soluble IL-6 receptor (sIL-6R), IL-5, CCL-3, IL-17, and transforming growth factor-beta 1 were not significantly altered in individuals with MDD compared to HCs. Heterogeneity was large (I² : 51.6-97.7%), and sources of heterogeneity were explored (e.g., age, smoking status, and body mass index).

CONCLUSION

Our results further characterize a cytokine/chemokine profile associated with MDD. Future studies are warranted to further elucidate sources of heterogeneity, as well as biosignature cytokines secreted by other immune cells.

Econazole induces increases in free intracellular Ca2+ concentrations in human osteosarcoma cells

Econazole is an antifungal drug with different in vitro effects. However, econazole's effect on osteoblast like cells is unknown. In human MG63 osteosarcoma cells, the effect of econazole on intracellular Ca2+ concentrations ([Ca2+]i) was explored by using fura-2. At a concentration of 0.1 μM, econazole started to cause a rise in [Ca2+]i in a concentration-dependent manner. Econazole-induced [Ca2+]i rise was reduced by 74% by removal of extracellular Ca2+. The econazole-induced Ca2+ influx was mediated via a nimodipine-sensitive pathway. In Ca2+ free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+ ATPase, caused a [Ca2+]i rise, after which the increasing effect of econazole on [Ca2+]i was abolished. Pretreatment of cells with econazole to deplete Ca2+ stores totally prevented thapsigargin from releasing Ca2+. U73122, an inhibitor of phospholipase C, abolished histamine (an inositol 1,4,5-trisphosphate dependent Ca2+ mobilizer)-induced, but not econazoleinduced, [Ca2+]i rise. Econazole inhibited 76% of thapsigargin-induced store-operated Ca2+ entry. These findings suggest that in MG63 osteosarcoma cells, econazole increases [Ca2+]i by stimulating Ca2+ influx and Ca2+ release from the endoplasmic reticulum via a phospholipase C-independent manner. In contrast, econazole acts as a potent blocker of store-operated Ca2+ entry.

Energetic and kinetic dataset on interaction of the vacancy and self-interstitial atom with the grain boundary in α-iron

We provide the dataset of the vacancy (interstitial) formation energy, segregation energy, diffusion barrier, vacancy-interstitial annihilation barrier near the grain boundary (GB) in bcc-iron and also the corresponding interactive range. The vacancy-interstitial annihilation mechanisms in the bulk, near the GB and at the GB at across scales were given.

Second hernia repairs in children-a nationwide study

BACKGROUND

Second inguinal hernia repairs may be needed either owing to contralateral metachronous hernia (MH) or ipsilateral recurrent hernia (RH). In this study, we estimated the incidence rates of MH and RH from a large nationwide database.

METHODS

The information was obtained from the National Health Insurance Database (with 23 million insurants). Subjects with hernia repairs were identified, and information such as age, gender, unilateral/bilateral procedures in the first and second hernia repairs were analyzed.

RESULTS

Among the 92,308 newborns observed from their births to the end of 6th year, 3881 had first hernia repairs. Among the 3068 subjects with first unilateral repairs, 307 had second repairs, and among the 813 with first bilateral repairs, 15 had second repairs. The incidence of second repairs was 10.85% (13.71% if <1year old) after first unilateral repairs and was 1.23% (0.63% if <1year old) after first bilateral repairs.

CONCLUSIONS

The incidence of RH (estimated from second hernia repairs after first bilateral repairs) was 1.23%. The incidence of MH (from second repairs after first unilateral repairs) was 9.62%. These incidence rates are consistent with other published reports.

Extraordinary high ductility/strength of the interface designed bulk W-ZrC alloy plate at relatively low temperature

The refractory tungsten alloys with high ductility/strength/plasticity are highly desirable for a wide range of critical applications. Here we report an interface design strategy that achieves 8.5 mm thick W-0.5 wt. %ZrC alloy plates with a flexural strength of 2.5 GPa and a strain of 3% at room temperature (RT) and ductile-to-brittle transition temperature of about 100 °C. The tensile strength is about 991 MPa at RT and 582 MPa at 500 °C, as well as total elongation is about 1.1% at RT and as large as 41% at 500 °C, respectively. In addition, the W-ZrC alloy plate can sustain 3.3 MJ/m² thermal load without any cracks. This processing route offers the special coherent interfaces of grain/phase boundaries (GB/PBs) and the diminishing O impurity at GBs, which significantly strengthens GB/PBs and thereby enhances the ductility/strength/plasticity of W alloy. The design thought can be used in the future to prepare new alloys with higher ductility/strength.

Nanostructured fuzz growth on tungsten under low-energy and high-flux He irradiation

We report the formation of wave-like structures and nanostructured fuzzes in the polycrystalline tungsten (W) irradiated with high-flux and low-energy helium (He) ions. From conductive atomic force microscope measurements, we have simultaneously obtained the surface topography and current emission images of the irradiated W materials. Our measurements show that He-enriched and nanostructured strips are formed in W crystal grains when they are exposed to low-energy and high-flux He ions at a temperature of 1400 K. The experimental measurements are confirmed by theoretical calculations, where He atoms in W crystal grains are found to cluster in a close-packed arrangement between {101} planes and form He-enriched strips. The formations of wave-like structures and nanostructured fuzzes on the W surface can be attributed to the surface sputtering and swelling of He-enriched strips, respectively.

Using hydrological simulation to detect human-disturbed epoch in runoff series

Runoff in major rivers in China has been decreasing in recent decades, mainly due to climate change and human activity. River basin managers have a critical interest in detecting and diagnosing non-stationaries in runoff time series. Here we use a rainfall runoff model-based approach to identify the human-disturbed periods of the record. The method is applied to the Kuye River catchment, located in the Loess Plateau, China. The SimHyd model performs well for simulation of monthly natural discharges, and the method suggests that discernable human influence began in 1980. Anthropogenic effects were detectable several years earlier at the downstream stations than the upstream stations, consistent with pace and timing of soil and water conservation measures implemented across the Kuye River catchment.

Origin of the crossover in dynamics of the sub-Rouse modes at the same temperature as the structural α-relaxation in polymers

The nature of the liquid-glass transition remains an unsolved fundamental problem. One aspect is the striking change in dynamics of the structural α-relaxation generally observed at a temperature T(B) above Tg in all glass-formers. More intriguing in the case of polymers is that the change of dynamics occurs not only in the structural α-relaxation but also in the sub-Rouse modes, i.e. chain modes in between the α-relaxation and the Rouse modes. However, the nature of the dynamic crossover of the sub-Rouse modes remains unclear. In this paper, the dynamics of a series of poly(n-alkyl methacrylates) with different molecular weights and microstructures studied by mechanical spectroscopy are reported. We demonstrate that the sub-Rouse modes exhibit a similar crossover of dynamics at the same T(B) as the α-relaxation. This property shared by the two viscoelastic mechanisms is remarkable. By invoking the results from the studies using positron annihilation spectroscopy and adiabatic calorimetry, we show that both viscoelastic mechanisms are coupled to density, correlated with the change of the configuration entropy, and are intermolecularly cooperative. The time scale of sub-Rouse modes at T(B) of the polymers studied is approximately independent of molecular weight and micro-structure of the polymers studied. The findings enhance the understanding of the sub-Rouse modes and their manifestation in the viscoelasticity of polymers in the glass-rubber transition region.

Surgical outcomes of total colonic aganglionosis in children: a 26-year experience in a single institute

BACKGROUND

There is a lack of consensus regarding the treatment of total colonic aganglionosis (TCA) with respect to perioperative morbidity, mortality, complications, and functional outcomes. The aim of this study was to review the results of surgical TCA treatment over a 26-year period and characterize the outcomes.

METHODS

We retrospectively reviewed the clinical characteristics, surgical courses, and outcomes of TCA patients who underwent definitive pull-through operations from 1986 to 2012. Follow-up data were collected by chart reviews and telephone interviews using a standardized questionnaire.

RESULTS

We identified nine infants with TCA (8.6%) from among 105 infants with Hirschsprung's disease treated during the 26-year period. Neither sex predominated (male/female ratio = 4:5). All infants underwent laparotomies and simultaneous enterostomies. All patients eventually underwent modified Duhamel pull-through procedures at a mean age of 179 days (range, 47-352 days). Two infants died of complications after surgery including heart failure and sepsis. The remaining infants recovered smoothly with antilaxative medications, and all but one was weaned off these medications. Although the surviving patients did not catch up on growth, they and their families were satisfied with the surgical results.

CONCLUSION

Infants with TCA had satisfactory outcomes after the modified Duhamel pull-through operation. Based on our experience, we suggest that the pull-through operation could be performed earlier, even when there are loose stools from the enterostomy.

A universal scaling law of grain chain elasticity under pressure revealed by a simple force vibration method

The grain contact force, the key player in determining the mechanical properties of grain materials, depends on the elastic modulus and deformation (δ) of grains. However, our knowledge on their relationship in a three-dimensional granular medium is limited mainly owing to the difficulty of realizing direct experimental investigation. Using a simple force vibration technique, we measure the dissipation spectra (the frequency response) of three kinds of grains with different elastic moduli under different pressures (to change the grain deformation). The dissipation spectra exhibit multiple resonant peaks, indicative of the resonance of grain chains with different lengths. This allows us to quantitatively characterize the elastic behaviors of grain chains. A universal correlation of the resonant frequency (f) of a grain chain with deformation is observed for all granular systems with different material properties (Young's modulus E, density ρ and Poisson's coefficient ν): f(2) ∝ δ(1/2)E/ρ(1 - ν). The deformation of the grain chain under pressure follows a p(2/3) pressure dependence. This general behavior suggests that the pressure-induced deformation of the grain chain under low-frequency weak shear vibration is overwhelmed by the nonlinear Hertzian contact elasticity.

Modified prepuce unfurling for buried penis: a report of 12 years of experience

BACKGROUND/OBJECTIVE

About 10 years ago, we started to correct buried penis using the technique of modified prepuce unfurling. We have made modifications in the years since our preliminary results were reported in 2002.

METHODS

One hundred and thirty-four patients received modified prepuce unfurling since 2000, with ages ranging from 2 months to 33 years. The surgical procedures included the removal of the narrowest part of the prepuce, dissection of the fibrotic tissue from the Buck's fascia, and unfurling the inner prepuce to cover the penis. Most patients had their procedures in day care service. No urinary catheter was needed. All patients were followed up for at least 2 months.

RESULTS

Most patients had satisfactory results. All patients had the glans exposed after surgery, although one patient needed reoperation for prolonged edema and two patients had wound infections.

CONCLUSION

Modified prepuce unfurling is a safe and effective method to correct buried penis.

Unruptured saccular aneurysm presenting migraine

Headache can be attributed to cranial or cervical vascular disorders including ischemic stroke or transient ischemic attack, non-traumatic intracranial hemorrhage, unruptured vascular malformation, arteritis, carotid-vertebral artery pain, and cerebral venous thrombosis. Here, we present a case report of unruptured saccular aneurysm with migraine. The patient was a previously healthy 32-year-old man with repeated episodes of headache for 6 years. Findings for computed tomography and magnetic resonance imaging of the head were normal. Head magnetic resonance angiography revealed a small, nodule-like protuberance seen in the anterior communicating artery. Based on his clinical features and ancillary examinations, the patient was diagnosed with migraine without aura. The patient subsequently underwent digital subtraction angiography (DSA), which revealed a 2-mm cystic protuberance in the superoposterior anterior communicating artery. The patient underwent stent-assisted coil embolization of the aneurysm. Subsequent DSA results indicated no recurrence of aneurysm and no recurrence of headache was reported after surgical treatment.

A newly designed total implantable venous access device in rats for research with high efficiency and low cost

BACKGROUND

In this study, we introduced a newly designed totally implantable device for long-term vascular access in rats and compared its efficacy, related complications, and cost-effectiveness with conventional exteriorized jugular vein catheters.

METHODS

Forty adult male Sprague-Dawley rats, weighing 250-300 g, were equally divided into two groups (I and II) and all underwent jugular vein catheterization surgery. The totally implanted device was used in group I and conventional exteriorized catheters were used in group II. The functionality of each catheter was checked every 3 d and evaluation included vascular accessibility, patency, and infection. The weight of the animal and microbial culture from the wound and tube were also monitored. We analyzed the cause of vascular access failure and complications, both mechanical and infectious, and compared related variables.

RESULTS

The proportions of 9-d patency and 30-d patency in group I were 90% (18/20) and 75% (15/20), respectively, and in group II 80% (16/20) and 35% (7/20), respectively. There was a statistically significant difference in 30-d patency. The rats in group II were more liable to involve vascular access failure because of catheter dislodgment and had a higher infection rate (P = 0.001). Daily body weight gain was also greater in group I than in group II (2.46 ± 0.59 g/d versus 1.84 ± 0.96 g/d; P = 0.02).

CONCLUSIONS

This newly designed and totally implanted device substantially increases the success rate of long-term venous access compared with conventional methods. It reinforces the merits of the subcutaneous port and a tethered swivel system and overall has better performance and reliability. Furthermore, given its low cost and the high level of effectiveness offered, this technology could be a powerful tool to be used in future translational medicine research, especially in cases of long-term intravascular administration.

A longitudinal cohort study of incidence rates of inguinal hernia repair in 0- to 6-year-old children

BACKGROUND/PURPOSE

This study provides epidemiologic data on the incidence of inguinal hernia repair in preschool children using the Taiwan National Health Insurance Research Database. We believe that the data on hernia repair in said database provide a close approximation of the true incidence of inguinal hernia in young children.

METHOD

A cohort of 1,073,891 deidentified individuals was randomly selected from an insured population of 23 million. Subjects born during the period 1997-2004 were followed from birth to 6 years. The chi-square test and logistic regression modeling were used for statistical analyses.

RESULT

A total of 92,308 individuals were born during the study period. Of these individuals, 3881 underwent hernia repairs. The cumulative incidence of hernia repair in children aged 0 to 6 years was 4.20%/7 years. The boy/girl ratio was 4.27:1 and the unilateral/bilateral ratio was 3.77:1. The incidence of hernia repair among boys was highest during the first year of life, but then decreased with age. In contrast, the incidence among girls remained stable during the first 6 years of life. Boys younger than 1 year had more bilateral repairs than boys in other age groups (p<0.0001) and girls had significantly more bilateral repairs than boys (p<0.0001). Subjects with a history of preterm birth also had a higher incidence of hernia repair than subjects who were born at full term (odds ratio=2.34, p<0.0001).

CONCLUSION

Yearly incidence of hernia repair was obtained from a nationwide database. Some of the observations have not been reported elsewhere.

Possible s±-wave pairing evidenced by midgap surface bound states in Fe-pnictide superconductors

A phenomenological theory of tunneling spectroscopy for Fe-pnictide superconductors is developed by taking into consideration asymmetric interface scattering between particle and holes. It is shown that, consistent with anti-phase s(±)-wave pairing, appreciable zero-energy surface bound states exist on the [100] surface of Fe-pnictide superconductors. However, in contrast to the [110] bound states in d-wave cuprate superconductors, these bound states arise as a result of non-conservation of momentum perpendicular to the interface for tunneling electrons and the s(±) pairing, and hence they can only exist in a small window (~ ± 6°) in the orientation of edges near the [100] direction. Our results explain why a zero-bias conductance peak is often observed in tunneling spectroscopy and why, when it disappears, two coherent peaks show up. These results provide unambiguous signals to test for possible s(±)-wave pairing in Fe-pnictide superconductors.

Amelioration of Paraquat-Induced Pulmonary Injury by Mesenchymal Stem Cells

Acute paraquat (PQ) poisoning induces redox cycle and leads to fatal injury of lung. Clinical management is supportive in nature due to lack of effective antidote, and the mortality is very high. Mesenchymal stem cells (MSCs) process the properties of immunomodulation, anti-inflammatory, and antifibrotic effects and oxidative stress resistance. MSC transplantation may theoretically serve as an antidote in PQ intoxication. In this study, we examined the potential therapeutic effects of MSCs in PQ-induced lung injury. The degree of PQ toxicity in the rat type II pneumocyte cell line, L2, and MSCs was evaluated by examining cell viability, ultrastructural changes, and gene expression. L2 cells treated with 0.5 mM PQ were cocultured in the absence or presence of MSCs. For the in vivo study, adult male SD rats were administered an intraperitoneal injection of PQ (24 mg/kg body weight) and were divided into three groups: group I, control; group II, cyclophosphamide and methylprednisolone; group III, MSC transplantation 6 h after PQ exposure. MSCs were relatively resistant to PQ toxicity. Coculture with MSCs significantly inhibited PQ accumulation in L2 cells and upregulated the expression of antioxidative heme oxygenase 1 and metallothionein 1a genes, reversed epithelial-to-mesenchymal transition, and increased the viability of PQ-exposed L2 cells. Treatment with MSCs resulted in a significant reduction in severity of liver and renal function deterioration, alleviated lung injury, and prolonged the life span of rats. Altogether, our results suggest that MSCs possess antidote-like effect through multifactorial protection mechanism. The results of this preclinical study demonstrate that transplantation of MSCs may be a promising therapy and should be further validated clinically.

A bacteria injection scheme for in situ bioaugmentation

This article presents an innovative design for inoculating the desired organisms to stratified geological layers at desired rates during in-situ bioaugmentation. The new delivery system consists of intermittent porous tubes connected in series with impermeable polyethylene tubes that run horizontally in each stratified layer of a contaminated aquifer. A bioaugmentation test using the new delivery system was conducted to inject an enriched culture of Escherichia coli (E. coli). Results of the test indicated that the distribution of E. coli through each porous tube was fairly uniform. A mathematical model previously developed to calculate the distribution of water flow through each porous tube was modified to calculate the distribution of E. coli. Geological layers often have different hydraulic conductivities. By controlling the permeability and the length of porous tubes placed in stratified layers, the new design provides a means to selectively deliver aqueous bacteria to various layers at desired rates according to aquifer heterogeneity.

Interplay between periodicity and nonlinearity of indirect excitons in coupled quantum wells

Inspired by a recent experiment of localization-delocalization transition (LDT) of indirect excitons in lateral electrostatic lattices (Remeika et al 2009 Phys. Rev. Lett. 102 186803), we theoretically investigate the interplay between periodic potential and nonlinear interactions of indirect excitons in coupled quantum wells. It is shown that the model involving both attractive two-body and repulsive three-body interactions can lead to a natural account for the LDT of excitons across the lattice when reducing lattice amplitude or increasing particle density. In addition, the observations that the smooth component of the photoluminescent energy increases with increasing exciton density and that the exciton interaction energy is close to the lattice amplitude at the transition are also qualitatively explained. Our model provides an alternative way of understanding the underlying physics of the exciton dynamics in lattice potential wells.

Liver transplantation for a patient with homocystinuria

A 24-yr-old man was diagnosed with HCU during neonatal screening and remained on a pyridoxine, vitamin B12, folic acid, and betaine regimen with dietary methionine restriction for more than 10 yr. He had normal mental development, marfanoid appearance, myopia because of lens dislocation, and recurrent ankle subluxation during adolescence. Thereafter, he was a poor adherent to the conventional diet-restrictive therapy, and LT was considered when he developed hypertension and multiple infarctions over the right cerebellum early in the second decade of his life despite taking aspirin as a prophylaxis from 17 yr of age. In November 2009, he received a deceased whole LT from a blood group compatible donor. Along with the success of the transplantation, he was completely disease free without dietary or nutritional control. To the best of our knowledge, this is the first case of LT intended to cure HCU, and with promising results. This case provides an insight into the role of LT for this congenital metabolic disease, for which the decision should be made by judging between the severity of the disease and the risk of the operation, as well as the life quality of the patient.

Child abuse in medical setting presenting as gross hematuria: diagnosis by DNA short tandem repeats

Two sisters, aged 15 and 13 years, had previous epithelioid angiomyolipoma of the kidney and suspected thin basement membrane disease, respectively. They presented with 2 years of gross hematuria and new-onset heavy proteinuria. Extensive investigations failed to find an overt cause of their urinary manifestations. The diagnosis of child abuse in a medical setting was confirmed by DNA short tandem repeats analysis, which are the first documented cases in which factitious hematuria was thus diagnosed. Complex forms of child abuse in a medical setting may require forensic tests such as DNA short tandem repeats analysis for diagnosis.

Plasmoid ejection and secondary current sheet generation from magnetic reconnection in laser-plasma interaction

Reconnection of the self-generated magnetic fields in laser-plasma interaction was first investigated experimentally by Nilson et al. [Phys. Rev. Lett. 97, 255001 (2006)] by shining two laser pulses a distance apart on a solid target layer. An elongated current sheet (CS) was observed in the plasma between the two laser spots. In order to more closely model magnetotail reconnection, here two side-by-side thin target layers, instead of a single one, are used. It is found that at one end of the elongated CS a fanlike electron outflow region including three well-collimated electron jets appears. The (>1 MeV) tail of the jet energy distribution exhibits a power-law scaling. The enhanced electron acceleration is attributed to the intense inductive electric field in the narrow electron dominated reconnection region, as well as additional acceleration as they are trapped inside the rapidly moving plasmoid formed in and ejected from the CS. The ejection also induces a secondary CS.

Oxidative degradation of propachlor by ferrous and copper ion activated persulfate

The process of in situ chemical oxidation (ISCO) by persulfate (S(2)O(8)(2-)) can be accelerated by metal ion activation, which more effectively degrades subsurface pollutants by enhancing sulfate radical (SO(4)(-)) generation. This study compared the results of propachlor degradation by Cu(2+) and Fe(2+) activated persulfate and revealed differing degradation kinetics and mechanisms between the two types of activation system. The activation of persulfate by Fe(2+) ions generally resulted in rapid degradation in the early stage, but was accompanied by a dramatic decrease in efficiency due to the rapid depletion of Fe(2+) by the sulfate radicals generated. In contrast, the Cu(2+) activated persulfate had a longer lasting degradation effect and a proportionally greater degradation enhancement at elevated Cu(2+) concentrations. An optimal Fe(2+) concentration should be sought to activate the persulfate, as a high Fe(2+) concentration of 2.5mM or above, as was used in this study, may inhibit propachlor degradation due to the competitive consumption of sulfate radicals by the excess Fe(2+) ions. Higher temperatures (55°C compared with 30°C) resulted in enhanced metal activation, particularly with the Cu(2+) activated system. Furthermore, acidic conditions were found to be more favorable for propachlor degradation by metal activated persulfate. The ecotoxicity of degraded propachlor samples, which was indicated by average well color development (AWCD) for its microbial community activity, was confirmed to be decreased during the degradation processes with these two ions activated persulfate.

Kinetics and mechanism of propachlor reductive transformation through nucleophilic substitution by dithionite

Chloroacetanilide herbicides are extensively used in the control of weeds and have widely resulted in nonpoint contamination of groundwater and soil resources. In the attempt to achieve better remediation for herbicide-contaminated resources, we investigated the reductive transformation of propachlor through nucleophilic substitution by dithionite (S(2)O(4)(2-)). Results showed that propachlor underwent rapid dechlorination in the presence of dithionite. The reaction was of second-order kinetics and strongly influenced by pH and temperature. At pH 7.0 and temperature 308K, the rate constant of propachlor dechlorination was estimated at 123.4±0.7M(-1)h(-1). Within the pH range tested (3.0-9.5), higher pH promoted the ionization of dithionite, resulting in a more active nucleophilic reagent of S(2)O(4)(2-) to enhance the propachlor transformation rate. Similarly, higher reaction temperature overcame the activation barrier of steric hindrance in propachlor structure and accelerated the excitation of dithionite, in which higher rate constants of propachlor reductive dechlorination were obtained. Dechlorination was found to be the first and necessary step of propachlor nucleophilic substitution by dithionite. Sulfur nucleophile substituted compounds, including propachlor dithionite, propachlor ethanesulfonic acid (ESA), and hydroxyl propachlor, were identified as the dechlorination products of propachlor, indicating bimolecular nucleophilic substitution (S(N)2) as the mechanism for propachlor transformation initiated by dithionite.