Theoretical insights into the defect performance of the wide bandgap semiconductor BaS.

Wide bandgap semiconductors materials (WBGSMs) are of great interest for their applications in transparent electronics and power electronics. Recent studies have shown that BaS is a potential transparent conducting material but the knowledge of it is deficient. Herein, we systemically investigate its electronic structure and evaluate the effects of its intrinsic defects and extrinsic dopants by utilizing the hybrid density functional method. The obtained results show that BaS is an indirect bandgap semiconductor with a bandgap of 3.88 eV. Its electron-effective mass is very small (0.33 m0). We find that the intrinsic n-type conductivity of BaS is connected with the shallow donor defect sulfur vacancy (VS). Regarding extrinsic dopants (group IA atoms), we find that Li and Na are favorable n-type dopants, while K and Rb are p-type dopants. Among these impurities, the Li interstitial (Liint) configuration possesses the lowest formation energy of 0.114 eV. Based on thermodynamic simulations, we find that the electron density can reach 2.39 × 1020 cm-3 in Li-doped BaS at room temperature, which is comparable to those of typical WBGSMs In2O3, BaSnO3, and ß-Ga2O3. We expect BaS could replace typical WBGSMs in some applications. Moreover, its component elements Ba and S are non-toxic, cheap, and earth-abundant, making it a very competitive candidate for WBGSMs. Based on these results, we deem BaS a promising candidate for optoelectronic applications.

[Effects of cortical bone trajectory screw in adjacent-segment disease after posterior lumbar interbody fusion].

Objective: To investigate the effect of the cortical bone trajectory (CBT) screw fixation combined with midline lumbar fusion (MIDLF) for adjacent spondylopathy after posterior lumbar interbody fusion. Methods: A retrospective analysis was conducted in 16 patients, including 9 males and 7 females, with a mean age of (68±6) years, who underwent revision surgery for adjacent spondylopathy after posterior lumbar fusion surgery using CBT combined with MIDLF technology in Sir Run Run Shaw Hospital, Zhejiang University from May 2013 to August 2019. The reasons for revision were radiculalgia in 4 cases, intermittent claudication in 10 cases and protrusive dissociate in 2 cases. Eleven cases had 1 segment fused in the first operation, while the other 5 cases received fusion in 2 segments. The average interval time between the first operation and the revision operation was (7.5±2.0) years. For the levels underwent revision, 1 case was L2/3, 6 cases were L3/4, 7 cases were L4/5 and 2 cases were L5/S1. Before the operation, all the patients took X-rays scans of the thoracic and lumbar spine. CT and MRI scans were also performed. The operation time, intraoperative bleeding, surgical complications, visual analog scale (VAS) of low back and leg pain before the operation and at each follow-up were all recorded. Oswestry disability index (ODI) questionnaire was used to evaluate the functional improvement of patients after the operation. Results: All operations were completed successfully. The operation time was 120-240 (170±30) mins, intraoperative bleeding was 100-280 (220±45) ml. One case had a slight split in the isthmus, and the screw was inserted smoothly after adjusting the insertion point. In one case, the cerebrospinal fluid leaked during the operation and was successfully treated with conservative methods including no pillow supine treatment and strengthened anti-infection. The average follow-up time was of (19.5±1.3) months. The VAS of low back pain was 2.9±1.7 before the operation and it was 1.8±0.5 at the last follow-up, and the difference was statistically significant (P<0.01). The VAS of leg pain was 5.9±1.5 before the operation and it was 1.5±0.4 at the last the follow-up (P<0.01). The ODI score was 34.5±3.2 preoperatively and it decreased to 12.6±4.2 at the last follow-up, the difference was statistically significant (P<0.01). Conclusion: CBT technique combined with MIDLF for the adjacent-segment disease after posterior lumbar interbody fusion is minimally invasive and convenient, with good clinical effects. This technique can be used as an option for the revision of adjacent spondylopathy.

[Clinical effects of adjacent fasciocutaneous flaps in repairing small wounds with bone or steel plate exposure in anterior tibia].

Objective: To explore the clinical effects of adjacent fasciocutaneous flaps in repairing small wounds with bone or steel plate exposure in anterior tibia. Methods: Twelve patients with small wounds of bone or steel plate exposure in anterior tibia covering area of 2 cm×2 cm to 5 cm×3 cm were admitted to our unit from January 2014 to December 2016. A circular or elliptical adjacent fasciocutaneous flap was designed on the normal skin located at the inside or outside of the wound according to the size of wound after thorough debridement. The pedicle of the flap was located at the proximal end and transferred through the subcutaneous tunnel to cover the wound. The sizes of flaps were 3 cm×3 cm to 6 cm×4 cm. Flaps were fixed with interrupted sutures and drainage rubber sheets were placed under the flaps. The drainage rubber sheets were removed within 24 to 48 hours. The donor area was repaired by medium-thickness skin graft collected from homolateral outer thigh. Results: All the flaps of 9 patients survived. Two patients had necrosis at the distal end of the flaps and were cured by changing dressing. One patient had tension blisters on the flap and was cured by removing blisters and improving microcirculation. All patients were followed up for 3 months, and the flaps were good in blood supply, appearance, and color, with hypaesthesia. Conclusions: Repair of small wounds with bone or steel plate exposure in anterior tibia by adjacent fasciocutaneous flap is simple in surgical procedure and does not damage the well-known blood vessels, and the appearance, texture, and thickness of flaps are close to the skin of anterior tibia region. It is a good choice for repairing this kind of wounds and worth promoting in clinic.

[Analysis on treatment of extremely severe burn patients with severe inhalation injury in August 2nd Kunshan factory aluminum dust explosion accident].

Objective: To summarize the measures and experience in diagnosis and treatment of extremely severe burn patients with severe inhalation injury in dust explosion accident. Methods: The medical records of 13 patients with extremely severe burn complicated with severe inhalation injury in August 2nd Kunshan factory aluminum dust explosion accident who were treated at the First Affiliated Hospital of Soochow University (hereinafter referred to as our hospital) on August 2nd, 2014, were retrospectively analyzed. All the patients were transferred to our hospital 3-8 hours after injury under the condition of inhalation of pure oxygen. Twelve patients underwent tracheotomy within 5 hours after admission, while 1 patient underwent tracheotomy before admission. All the patients were in ventilator-assisted respiration, with synchronized intermittent mandatory ventilation combined with positive end expiratory pressure. All the patients underwent thorax or limbs escharotomy on the second day after admission, so as to reduce the restrictive ventilatory dysfunction caused by the contraction of thorax eschar and the terminal circulation disorder caused by the contraction of limbs eschar. All the patients underwent electronic bronchoscopy within 48 hours after admission, airway secretion were cleared and airway lavage were carried out under electronic bronchoscope according to the patients' condition, and the sputum, lavage solution, pathological tissue were collected for microbiological culture. All the patients underwent chest X-ray examination on the second day after admission and reexamination as required. Patients were all treated with a combination of broad-spectrum antibiotics early after admission to control lung and systemic infection. One patient was treated with extracorporeal membrane oxygenation for acute respiratory distress syndrome 1 week after admission. Results: One patient suffered from cardiopulmonary arrest during tracheotomy, which recovered autonomous respiration and cardiac impulse after cardiopulmonary resuscitation. Three patients showed decreased pulse oxygen saturation (SpO(2)) within 48 hours after injury, and the SpO(2) returned to normal after sputum aspiration, scab removal and lavage under electronic bronchoscope. During the course of disease, bacteria were cultured from wound exudate of 7 patients, bacteremia occurred in 10 patients, and sputum microbiological culture results of 13 patients were positive. Eight of the 13 patients in this group survived, and 5 died. One patient died 19 days after injury, and 4 patients died 33-46 days after injury. The main cause of death was multiple organ dysfunction syndrome induced by severe septic shock eventually. Conclusions: For this batch of patients with extremely severe burn complicated with severe inhalation injury caused by dust explosion accident, the treatment and cure measures including early definite diagnosis and timely tracheotomy, the application of effective ventilation, the effective treatment of respiratory system complications, and rational use of antibiotics for the control of lung infection obtained quite good curative effect.

A modification and validation of quantitative morphometry classification system for osteoporotic vertebral compressive fractures in mainland Chinese.

This study described a modified quantitative morphometry (mQM) system adapted to specific reference values for Mainland Chinese population. The mQM system is validated using the Genant Semiquantative system and is sensitive for detecting vertebral height changes and predicting cement leakage after percutaneous kyphoplasty (PKP) in patients with osteoporotic vertebral compressive fracture (OVCF). INTRODUCTION: OVCF is a manifestation of osteoporosis. To improve clinical management of osteoporosis, the quantitative morphometry (QM) system has been widely used for the early diagnosis and precise classification of OVCF in developed countries. Here, we present an mQM system and validated its use in detecting OVCF in Mainland Chinese. METHODS: Using our mQM system, the pre- and post-operative values of vertebral heights were measured and evaluated in 309 Mainland Chinese who received percutaneous kyphoplasty (PKP) as OVCF treatment. Measurements and classification of fractures from the mQM system were validated by comparing to values obtained by the Genant semiquantative (SQ) method. Moreover, we evaluated the sensitivity of the mQM system by its ability to detect restoration of vertebral heights and predict cement leakage after PKP. RESULTS: The five classification of fractures, No deformity (ND), anterior wedge (AW), posterior wedge (PW), biconcavity (BC), and compression (CP), evaluated by the mQM method shared similar distribution characteristics compared to those obtained by the SQ method. In addition, mQM evaluation showed that the vertebra height of all fracture types showed significant restoration after PKP. The incidence of cement leakage was most common in CP (37.5%), followed by AW (31.6%), BC (26.5%), ND (23.7%), and PW (0.0%). CONCLUSIONS: Our mQM system is suitable for classification of fractures, detection of vertebral height restoration, and correlation of cement leakage after PKP in Mainland Chinese population.

[Effects of oblique lateral interbody fusion and transforaminal lumbar interbody fusion for lordosis correction in degenerative lumbar diseases].

Objective: To compare the operation time, estimated blood loss, clinical outcome and correction of lumbar lordosis between oblique lateral interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in patients with degenerative lumbar diseases. Methods: Seventy-three patients who underwent OLIF or TLIF surgery from January 2016 to December 2017 in Sir Run Run Shaw Hospital Zhejiang University were analyzed in this retrospective case-control study. The patients included 31 males and 42 females, with a mean age of 65.8 years (range, 36-88 years). Of the patients, there were 9 cases of calcified disc herniation, 34 cases of spinal stenosis, 17 cases of degenerative spondylolithesis, 12 cases of degenerative scoliosis and 1 case of isthmic spondylolithesis. According to the type of surgery, patients were divided into OLIF group (34 cases) and TLIF group (39 cases). The operation time, estimated blood loss and transfusion were recorded, pre-and post-operative visual analogue scale (VAS) for back pain and Oswestry Disability Index (ODI) were evaluated, and pre- and post-operative lumbar lordosis (LL) and fused segment lordosis (FSL) were measured. Student t test were used in comparison between groups. Results: Ten (29.4%) patients in OLIF group and all 39 (100%) patients in TLIF group were supplemented with posterior instrumentation (χ(2)=41.013, P<0.05). The average operation time and estimated blood loss was significantly lower in OLIF group than in those in TLIF group[(163±68) vs (233±79) min, (116±148) vs (434±201) ml, t=4.019, 6.964, both P<0.05]. There was no significant differences in decreases value in VAS and ODI after surgery between the two groups (t=1.716, 0.522, both P>0.05). The correction of LL was 4.0°±10.0° in the OLIF group and 4.2°±6.1° in the TLIF group; the correction of FSL was 4.1°±7.0° in the OLIF group and 5.2°±4.6° in the TLIF group, with no significant differences between the two groups too (t=0.139, 0.805, both P>0.05). The correction of LL was significantly higher in OLIF group with posterior instrumentation than that in TLIF group (9.9°±11.1° vs 4.2°±6.1°, t=2.180, P<0.05). Conclusions: Both OLIF and TLIF can restore LL to some extent, but OLIF has obvious advantages in the operation time and blood loss during surgery. When supplemented with posterior instrumentation, OLIF can achieve better correction of LL than TLIF.

Facet orientation and tropism: Associations with asymmetric lumbar paraspinal and psoas muscle parameters in patients with chronic low back pain.

BACKGROUND: Many studies have explored the relationship between facet tropism and facet joint osteoarthritis, disc degeneration and degenerative spondylolisthesis. However, the associations between facet orientation and tropism, and paraspinal muscles have not been studied. OBJECTIVE: To analyze the associations between facet orientation and tropism, and parameters of paraspinal muscles in patients with chronic low back pain. METHODS: Ninety-five patients with chronic low back pain were consecutively enrolled. Their facet joint angles were measured on computed tomography (CT) while gross cross-sectional area (GCSA), functional cross-sectional area (FCSA) and T2 signal intensity of lumbar paraspinal and psoas muscle were evaluated on magnetic resonance imaging (MRI). RESULTS: The GCSA and FCSA were significantly smaller for multifidus muscle (P< 0.001), but significantly larger for erector spinae and psoas muscles (P< 0.001), in coronally-orientated group than those in sagittally-orientated group. The differences of bilateral GCSA and FCSA of multifidus muscle were significantly larger in facet tropism group than those in no facet tropism group (P= 0.009 and P= 0.019). CONCLUSIONS: Muscular asymmetries may develop in the lumbar region of the spine, which are associated with facet asymmetry in patients with chronic low back pain. Longitudinal studies are needed to understand the causal relationship between facet orientation and tropism and muscular asymmetry in future.

The magnetocaloric effect with critical behavior of a periodic Anderson-like organic polymer.

We study the magnetocaloric effect and the critical behavior of a periodic Anderson-like organic polymer using Green's function theory, in which the localized f orbitals hybridize with the conduction orbitals at even sites. The field-induced metal-insulator transitions with the magnetic Grüneisen parameter showing |Γh|∼T(-1) power-law critical behaviour are revealed, which provides a new thermodynamic means for probing quantum phase transitions. It is found that the competition of up-spin and down-spin hole excitations is responsible for the double peak structure of magnetic entropy change (-ΔS) for the dominant Kondo coupling case, implying a double magnetic cooling process via demagnetization, which follows a power law dependence of the magnetic field h: -ΔS∼h(n). The local exponent n tends to 1 and 2 below and above TC, while has a minimum of 0.648 at TC, which is in accordance with the experimental observation of perovskite manganites Pr0.55Sr0.45MnO3 and Nd0.55Sr0.45MnO3 (J. Y. Fan et al., Appl. Phys. Lett., 2011, 98, 072508; Europhys. Lett., 2015, 112, 17005) corresponding to the conventional ferromagnets within the mean field theory -ΔS∼h(2/3). At TC, the -ΔS∼h curves with a convex curvature superpose each other for small V values, which are separated by the large V case, distinguishing the RKKY interaction and Kondo coupling explicitly. Furthermore, the critical scaling law n(TC) = 1 + (ß- 1)/(ß + γ) = 1 + 1/δ(1 - 1/ß) is related to the critical exponents (ß, γ, and δ) extracted from the Arrott-Noakes equation of state and the Kouvel-Fisher method, which fulfill the Widom scaling relation δ = 1 + γß(-1), indicating the self-consistency and reliability of the obtained results. In addition, based on the scaling hypothesis through checking the scaling analysis of magnetization, the M-T-h curves collapse into two independent universal branches below and above TC.

Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials.

UNLABELLED: To identify the role of vitamin K2 for the prevention and treatment of osteoporosis in postmenopausal women, we conducted this meta-analysis of 19 randomized controlled trials. Our results showed that vitamin K2 might play a role in maintaining the bone mineral density and in reducing the incidence of fractures for postmenopausal women with osteoporosis. INTRODUCTION: Vitamin K2 has been revealed to be effective in the prevention and treatment of osteoporosis in Japan, which was not confirmed in western countries. Thus, we conduct this meta-analysis to verify the hypothesis that vitamin K2 plays a role in the prevention and treatment of osteoporosis for postmenopausal women. METHODS: We searched the Cochrane Library, Pub Med, EMBASE, and ISI web of knowledge (until December 1, 2013) and reference lists of eligible articles. A meta-analysis of all-including randomized controlled trials was then performed. RESULTS: Nineteen randomized controlled trials encompassing 6759 participants have met the inclusion criteria. Subgroup analysis of postmenopausal women with osteoporosis revealed a significant improvement of vertebral BMD for both medium-term and long-term results favoring vitamin K2 group (p < 0.00001 and p = 0.0005). However, no significant difference in BMD changes was revealed for the non-osteoporosis subgroup analysis. As for the incidence of fractures, pooled analysis of the seven related studies demonstrated no significant difference in the incidence of fractures favoring vitamin K2 (RR = 0.63, p = 0.08). However, sensitivity analysis by rejecting the study inducing heterogeneity demonstrated a significant difference in the incidence of fractures favoring vitamin K2 (RR = 0.50, p = 0.0005). Significant differences were found in undercarboxylated osteocalcin reduction and osteocalcin increment. The result of adverse reaction analysis showed that vitamin K2 group seemed to have a higher adverse reaction rate (RR = 1.22, p = 0.06). CONCLUSIONS: This meta-analysis seemed to support the hypothesis that vitamin K2 plays kind of a role in the maintenance and improvement of vertebral BMD and the prevention of fractures in postmenopausal women with osteoporosis. The reduction of undercarboxylated osteocalcin and increment of osteocalcin may have some relation to the process of bone mineralization. However, the effect of vitamin K2 for postmenopausal women without osteoporosis had not been identified. Further high-quality RCTs with large sample size are needed to confirm the role of vitamin K2 in osteoporosis for postmenopausal women.

First-principles study of the ferroelectric and nonlinear optical properties of the LiNbO3-type ZnSnO3.

Electronic structures, spontaneous polarization, dynamical and nonlinear optical (NLO) properties of polar oxide ZnSnO(3) with LiNbO(3) (LN)-type structure have been investigated in the framework of density functional theory. By analyzing the Born effectives of LN-type ZnSnO(3), we find that Z* of Zn atoms show relatively large anomalous behavior. The spontaneous polarization is attributed to the large displacement of Zn atoms because of the mixed ionic-covalent character between the Zn-O bonds. The optical dielectric tensor is nearly the same; however the static dielectric tensor shows strongly anisotropy. Furthermore, the nonlinear optical properties are calculated by using 2n + 1 theorem applied to an electric-field dependent energy functional. The large dielectric constants and NLO susceptibilities indicate that the LN-type ZnSnO(3) would be a candidate as a high-performance dielectric and nonlinear optical material.

Bulk and surface sp half-metallic ferromagnetism in alkali metal pnictides with rocksalt structure: a first-principles calculation.

Recently, sp half-metallic ferromagnetism in alkali metal/alkaline earth pnictides (I/II-V) with zinc blende structure was predicted by first-principles calculations (Sieberer et al 2006 Phys. Rev. B 73 024404). To search for half-metallic ferromagnets with a more stable structure in alkali metal pnictides MX (M  = Li, Na, K; X =  N, P, As), we apply here first-principles all-electron and pseudopotential-method-based density functional theory to investigate the electronic and magnetic properties of these compounds with rocksalt structure. Five rocksalt compounds are found to be half-metallic ferromagnets with a magnetic moment of 2.00 µ(B)/f.u., and they are more stable energetically than the ones with zinc blende structure, which makes them more promising candidates for the possible growth of half-metallic films or ultrathin films on suitable semiconductor substrates. Furthermore, we show that both lithium- and nitrogen-terminated (111) surfaces of rocksalt lithium nitride retain the bulk half-metallic characteristic, and the surface atomic magnetic moments are enhanced compared to the bulk values.

Clinical cases seen in tsunami hit Banda Aceh: from a primary health care perspective.

The 2004 Indian Ocean earthquake and tsunami caused catastrophic damage to many cities on the rim of the Indian Ocean. Banda Aceh in Sumatra, Indonesia was particularly badly hit due to its close proximity to the epicenter. The Singapore Armed Forces Medical Team was one of the earliest medical teams to arrive in Banda Aceh, providing primary health care to the survivors. In the first 17 days of its operation, more than 2000 injured and sick were seen by the Medical Team at 2 locations within Banda Aceh. Approximately one-third of the patients suffered from infected superficial wounds on their limbs and faces. Many developed deep-seated necrosis of the skin tissue, requiring repeated wound dressing and debridement. Another one-third suffered from respiratory tract infection, some due to aspiration of sea water. There were relatively few major trauma and fracture cases seen, and there were a few cases of compression barotrauma of the tympanic membranes resulting from underwater immersion in the sea water. The casualty patterns seem consistent with those reported in other tsunami disasters, which differ distinctly from those seen in a pure earthquake disaster.

An assessment of electronically captured data in the patient care enhancement system (PACES) for syndromic surveillance.

INTRODUCTION: A common approach to the surveillance of emerging infectious diseases and agents of bioterrorism is to analyse electronically captured data for disease syndromes. The Patient Care Enhancement System (PACES) is a form of electronic medical records presently in service in the Singapore Armed Forces (SAF). We assess the feasibility of PACES data for surveillance, describe time-trends, and identify methods of sub-analysis which could improve performance. MATERIALS AND METHODS: Medical consults from July 2000 to June 2003 were extracted. Diagnosis codes were mapped to 7 infectious disease syndromes according to the categorisation in the Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE): gastrointestinal (GI), fever (FEVER), respiratory, (RESP), coma (COMA), neurological (NEURO), dermatologic-haemorrhagic (DERMHEM) and dermatologic- infectious (DERM-INF). RESULTS: A total of 732,233 episodes of care were analysed. Weekly periodicity was observed, with decreased weekend consults; there were no obvious seasonal trends in any of the syndromes. RESP, FEVER and GI syndromes were common events. Sub-analyses, either by restricting to cases with a repeated consultation, or grouping the data by medical centres, could dramatically lower thresholds used to flag outbreaks. CONCLUSION: In spite of the level of background noise inherent in a system consisting mainly of primary care consults, sub-analysis by medical centre, or restriction to cases with repeated consults were able to yield sensitive thresholds for outbreak detection.

An overview of the physiological effects of sustained high +Gz forces on human being.

In the search for the advantage in aerial combat, increasingly higher performance aircraft are being developed that impose ever greater acceleration force loads on the human pilot. The symptomatology associated with increasing +Gz acceleration forces, culminating in G-induced loss of consciousness caused by the cessation of cerebral blood circulation are described. The inability of the normal cardiovascular system mechanisms to provide adequate circulation to the brain and the eyes, and the resulting associated symptomatology and physiological changes are discussed. The normal weight, hydrostatic pressure and physiological ventilation/perfusion gradients in the lungs are exaggerated under high +Gz forces resulting in increased pulmonary arterio-venous shunting. This causes impairment of circulatory oxygenation and may also result in acceleration induced atelectasis. The effects of +Gz acceleration forces on the renal system and the limitations of the cervical musculature are also discussed. This paper serves to describe the human physiological responses to increased +Gz acceleration forces in an attempt to provide a better understanding of the body's reaction to such demanding physical stressors.

Adoptive immunotherapy of advanced renal cell cancer using PHA-stimulated autologous lymphocytes.

Patients with advanced renal cell carcinoma, previously failed maximal treatment with standard chemo-hormonal-radiation therapies, were treated with plant lectin phytohemagglutinin (PHA)-stimulated autologous peripheral blood lymphocytes in a 10-year study with a 16-year follow up period. In a phase I-II setting, 52 patients were given subcutaneously 40-80 x 10(6) PHA-stimulated lymphocytes weekly for 3 weeks and then escalated to a maximum number of 80 x 10(9) lymphocytes over the next 9 weeks at 3 week intervals. In vitro blastogenesis under study conditions (10 micrograms/ml PHA for 72 hr) measured by [3H]thymidine uptake was optimal with lymphocyte stimulating indexes approaching 300. Lymphocytes obtained from patients with breast cancer, melanoma and renal cell carcinoma responded to PHA similarly to those from normal volunteers. All patients that responded developed erythematous reactions at the sites of injection; malaise, joint paint and chill-fever for 24-48 hr. The patients that responded the best were those with at least 1 positive reaction out of 4 skin tests (tuberculosis, yeast, dermatophytin, mumps) prior to therapy. All toxicity was transient and did not exceed Grade I based on criteria of the Southwest Oncology Group. The majority of patients developed a lymphopenia in the first 24 hr followed by a lymphocytosis 48-72 hr later. For some patients the lymphocytosis was as much as 30% atypical lymphocytes. Of 41 evaluable patients, there were 5 complete responses, 8 partial responses, 3 stable diseases, and 25 progressive disease. The overall response rate was 32% and the median survival was 2.8 years.(ABSTRACT TRUNCATED AT 250 WORDS)