Hip subluxation in children with spinal cord injury: Incidence and influencing factors.

OBJECTIVE: Hip subluxation is a common complication in children with spinal cord injury. This study aimed to investigate the incidence and influencing factors of hip subluxation and discuss prevention strategies. METHODS: Medical records of children with spinal cord injury were reviewed. The inclusion criteria were as follows: (1) the patient was younger than 18 years old when injured; (2) absence of traumatic or congenital pathological changes of the hip at the time of injury. The migration percentage and acetabular index were selected to evaluate hip stability and acetabulum development. Influencing factors of sex, age, injury duration, severity, level, and spasticity were analyzed. RESULTS: A total of 146 children were enrolled. Twenty-eight children presented with hip subluxation and were significantly younger at the time of injury than those with normal hips (P = 0.002). The incidence of hip subluxation increased with the prolonged injury duration. Injury before age 6, complete injury, and flaccid lower extremities were significant influencing factors (P = 0.003, 0.004, and 0.015, respectively). The risk of hip subluxation decreased by 18% for every year older in injury age (P = 0.031) and decreased by 85% in children with spasticity (P = 0.018) than those without. However, the risk of hip subluxation in children with injury duration longer than 1 year was 7.1 times higher than those with shorter injury duration (P < 0.001). CONCLUSIONS: The incidence of hip subluxation in children with spinal cord injury increased with the injury duration. Younger children had immature hip development. Due to complete injury and flaccid muscle, lack of protection around the hip may lead to subluxation. Follow-up and prevention of hip subluxation need the joint effort of medical staff and families.

Inhibition of NKCC1 in spinal dorsal horn and dorsal root ganglion results in alleviation of neuropathic pain in rats with spinal cord contusion.

Previous studies have confirmed the relationship between chloride homeostasis and pain. However, the role of sodium potassium chloride co-transporter isoform 1 (NKCC1) in dorsal horn and dorsal root ganglion neurons (DRGs) in spinal cord injury (SCI)-induced neuropathic pain (NP) remains inconclusive. Therefore, we aimed to explore whether suppression of NKCC1 in the spinal cord and DRGs alleviate the NP of adult rats with thoracic spinal cord contusion. Thirty adult female Sprague-Dawley rats (8 week-old, weighing 250-280 g) were randomly divided into three groups with ten animals in each group (sham, SCI, and bumetanide groups). The paw withdrawal mechanical threshold and paw withdrawal thermal latency were recorded before injury (baseline) and on post-injury days 14, 21, 28, and 35. At the end of experiment, western blotting (WB) analysis, quantitative real-time Polymerase Chain Reaction (PCR) and immunofluorescence were performed to quantify NKCC1 expression. Our results revealed that NKCC1 protein expression in the spinal cord and DRGs was significantly up-regulated in rats with SCI. Intraperitoneal treatment of bumetanide (an NKCC1 inhibitor) reversed the expression of NKCC1 in the dorsal horn and DRGs and ameliorated mechanical ectopic pain and thermal hypersensitivities in the SCI rats. Our study demonstrated the occurrence of NKCC1 overexpression in the spinal cord and DRGs in a rodent model of NP and indicated that changes in the peripheral nervous system also play a major role in promoting pain sensitization after SCI.

Prognosis of traumatic spinal cord injury in children: Follow-up of 86 patients.

PURPOSE: The long-term situation of children with spinal cord injury (SCI) was investigated, and suggestions for helping them better return to the society were provided. METHODS: SCI patients less than 18 years old hospitalized in Beijing Boai Hospital from January 2011 to December 2020 were retrospectively analyzed. Information including motor function, complications, characteristic changes, self-care abilities, school attendance and social participation were collected by telephone interview and electronic questionnaire. All the answers were statistically analyzed. RESULTS: A total of 86 cases were enrolled, 77 girls and 9 boys, with a median injury age of 6 years and 2 months. The follow-up time was 3-130 months. The main cause of trauma in these children was sport injury (66.3%), the thoracic spinal cord was involved the most (91.9%), and complete SCIs accounted for the majority (76.7%). In terms of complications, children with complete SCIs were more likely to have urinary incontinence, constipation and characteristic changes (p < 0.05); whereas the incomplete SCIs often have spasticity (p < 0.05). As to the daily living abilities, children with incomplete lumbar SCIs were more capable to accomplish personal hygiene, transfer, and bathing independently than those with complete injuries, or cervical/thoracic SCIs, respectively (p < 0.05). Moreover, children older than 9 years care more able to dress and transfer independently than the youngers (p < 0.05). Wheelchair users accounted for 84.9% and more than half of them were able to propel wheelchair independently, and those who move passively in wheelchairs were mostly introverted kids (p < 0.05). Almost all (93.8%) children with incomplete injuries were able to walk independently. Most (79.1%) children continued to attending school, and 41.9% participated in interest classes. Unfortunately, 67.4% of the children spent less time playing with their peers than before the injury. CONCLUSION: SCIs impair physical structures and function of children, affect their independence in daily living, and restrict school attendance and social interaction. Comprehensive rehabilitation after injury is a systematic work. Medical staff and caregivers should not only pay attention to neurological function, but also help them improve self-care abilities. It is also important to balance rehabilitation training and school work and social participation.

Current status of traumatic spinal cord injury caused by traffic accident in Northern China.

The study aims to investigate the characteristics of traumatic spinal cord injury (TSCI) caused by motor vehicle collisions (MVCs). The study included 649 cases who experienced MVC-induced TSCI. The mean age was 37.3 years old, ranging from 1 to 82 years old. The male-to-female ratio was 2.7:1. We extracted data of gender, age, occupation, neurological level of injury, fracture level, complications, vehicle type, accident type and other features. The results showed that the most common vehicles involved in accidents were passenger cars (65.1%). Collision was the leading cause of MVCs (35.8%). The lesion level was cervical in 51.6% and thoracic in 42.2%. The most common fracture levels in drivers and passengers were C3-C7, while those in pedestrians were T11-L2. The frequency of tetraplegia (51.6%) was slightly higher than paraplegia (48.4%), and cases with tetraplegia with incomplete injury accounted for 61.2%. MVC-induced TSCI has unique clinical features. Collision was the most common cause. People sitting in cars were more likely to suffer from cervical fractures, while thoracolumbar fractures were more common in pedestrians. Tetraplegic cases were mainly incomplete injuries, while paraplegic cases were mainly complete injuries.

The Effect of GABAergic Cells Transplantation on Allodynia and Hyperalgesia in Neuropathic Animals: A Systematic Review With Meta-Analysis.

The role of GABAergic cell transplantation in improving neuropathic pain is controversial. We comprehensively searched the relevant literature to identify animal studies of GABAergic cell transplantation that recorded pain behaviors as an outcome according to the Cochrane Handbook 5.0.2. Controlled studies assessing the administration of GABAergic neurons or GABAergic neuronal progenitor cells to rat or mouse neuropathic pain animal models were included. Basic design information and mechanical allodynia thresholds and heat hyperalgesia thresholds data were collected. The risk of bias for the animal experiments was assessed according to the SYRCLE's tool. This study included 10 full-text articles. GABAergic cells transplantation leads to a statistically significant improvement of allodynia (SMD = 5.26; 95% confidence interval: 3.02-7.51; P < 0.001) and hyperalgesia (SMD: 4.10; 95% confidence interval: 1.84-6.35; P < 0.001). Differentiated GABAergic cells and without antibiotics using may have a better effect for improving neuropathic pain. GABAergic cell transplantation is a promising treatment for improving neuropathic pain. This systematic review and meta-analysis evaluated the effects of GABAergic cell transplantation on neuropathic pain, which can guide future clinical trials and possible clinical treatments, and better attenuate neuropathic pain caused by abnormal circuit hyperexcitability.

Clinical characteristics of pediatric traumatic spinal cord injury in China: A single center retrospective study.

OBJECTIVE: To investigate the clinical characteristics of children with traumatic spinal cord injury (SCI) admitted to a research rehabilitation center between 2011 and 2020, with a view to generate crucial data for understanding and prevention of pediatric traumatic SCI. DESIGN: Retrospective cohort study. SETTING: The National Rehabilitation Research Center of China, Beijing, China. PARTICIPANTS: Medical records and imaging data of children with traumatic SCI admitted to the rehabilitation research center from 2011 to 2020. INTERVENTIONS: Not applicable. OUTCOME MEASURES: Data on age, sex, cause of injury, neurological level of injury, impairment scale of SCI and details of spine fracture or dislocation were all collected and analyzed. RESULTS: A total of 351 patients were included in the study, including 133 males (37.9%) and 218 females (62.1%). There were 231 cases (65.8%) without spine fracture or dislocation. SCI without fracture or dislocation (SCIWORA) was the most common in children between the age of 5 and 14 years (77.9%), and injuries caused by sports were the most common in girls (90.8%). Among sports injuries, those due to a special dance movement called "Xia-Yao" in Chinese, which involves hyperextension of the trunk, constituted the majority, with the neurological level of injuries located predominantly in the middle (34.6%) and lower (44.2%) thoracic levels. CONCLUSION: Girls between the ages of 5 and 14 years constituted the majority of SCIWORA injuries at the thoracic levels, which were caused mainly by "Xia-Yao". Overall, careful attention should be paid to prevent this kind of injury in children.

Characteristics of Lumbar Bone Density in Middle-Aged and Elderly Subjects: A Correlation Study between T-Scores Determined by the DEXA Scan and Hounsfield Units from CT.

Purpose: To describe the characteristics of lumbar bone density in middle-aged and elderly subjects and explore whether there is a correlation between computed tomography (CT) values and the bone mineral density (BMD) T-scores of the lumbar vertebral cancellous bone. Methods: Forty-two subjects, including 25 males and 17 females, with a mean age of 56 years, who underwent BMD measurement and lumbar multislice spiral CT scan at the China Rehabilitation Research Center from January 2019 to December 2019 were selected. Dual-energy X-ray absorptiometry (DEXA) was applied to obtain the total BMD T-scores of the lumbar L1-L4 vertebrae. Results: The CT values decreased from L1 to L4 and were 145.91 ± 8.686 HU, 143.18 ± 8.598 HU, 137.39 ± 8.276 HU, and 135.23 ± 8.219 HU, respectively. The total CT value of L1-L4 was 140.43 ± 4.199 HU. The mean total BMD T-score of L1-L4 was -0.94. The CT values of the L1-L4 vertebrae were positively correlated with the total BMD T-scores of L1-L4 (r = 0.349, P < 0.001). The CT value of the left third of the same vertebrae was the highest, and there was a strong positive correlation between the regional CT value of the lumbar spine and the entire vertebra CT values (r > 0.7). Conclusion: The CT values of the lumbar spine can assist the measurement of the T-scores of lumbar BMD, which could aid in early opportunistic screening for osteopenia and preventing osteoporosis and vertebral compression fractures in middle-aged and elderly subjects. This trial is registered with ChiCTR2100049571.

Traumatic spinal cord injury caused by low falls and high falls: a comparative study.

BACKGROUND: Quite a few traumatic spinal cord injuries (TSCI) were caused by falls. However, the comparison of different causes of TSCI or the epidemiological characteristics of TSCI caused by falls of different heights are rare. This study investigated the epidemiological characteristics of TSCI caused by falls and conducted a comparison between low falls and high falls. METHOD: Data from cases with TSCI admitted to China Rehabilitation Research Center from 2010 to 2019 were collected, including age, gender, occupation, cause, neurological level, and severity of the injury in admission, combined injuries, complications, and rehabilitation length of stay. Mann-Whitney U and chi-square (χ2) tests were used to assess the differences between two groups at a statistical significance level of 0.05. RESULT: A total of 1858 TSCI cases were included and 41.7% were caused by falls, 11.4% by low falls and 30.3% by high falls, respectively. Patients with fall-induced TSCI were older and had a shorter rehabilitation length of stay than those with non-fall-induced TSCI. Patients with high fall-induced TSCI were younger and more likely to suffer from paraplegia, severer injuries, and combined injuries, and had longer time from injury to rehabilitation and rehabilitation length of stay, compared with patients with low fall-induced TSCI. CONCLUSION: Falls is the leading causes of TSCI and high fall is becoming more common. Attention not only should be paid to high falls for the severe injury and longer hospitalization, but also low falls due to the higher neurological level of the injury and the aging of population in China.

Six-year follow-up of a survivor of cervical spine fracture and dislocation with oesophageal perforation following long scarf syndrome - a case report and literature review.

BACKGROUND: Accidental strangulation due to scarf getting caught in the wheels of a vehicle or machine was called "Isadora Duncan Syndrome" or "Long Scarf Syndrome". Survival of concomitant fracture dislocation of cervical spine and oesophageal perforation following Long Scarf Syndrome was rarely described and medium-term follow-up for this lesion has not been reported. CASE PRESENTATION: We present a 39-year-old female who suffered accidental strangulation caused by the scarf around her neck getting trapped in the wheels of the a vehicle and was referred to our hospital forty days post injury. The CT examination showed a fracture dislocation at C5/6 levels with complete dissociation of the supporting structures. She developed paravertebral abscesses, cutaneous fistulas and oesophageal perforation confirmed by oesophagoscope. The patient was treated conservatively because of poor general condition and inappropriate initial treatment. Halo-vest was used to immobilize the cervical spine. The oesophagus-cutaneous fistula was managed with enteral tube feeding and repeated local care. The patient survived despite such severe injury. Nine months after the injury, the oesophageal perforation closed spontaneously and fixed malunion of the cervical spine was achieved. Six-year follow-up demonstrated that the patient survived with complete C5 tetraplegia. Literature associated with this lesion was reviewed and factors contributing to the survival were discussed. CONCLUSIONS: Concomitant fracture dislocation of cervical spine and oesophageal perforation following Long Scarf Syndrome is extremely rare with high risk of mortality. Though surgical intervention is always necessary, the optimal management for this kind of lesion should be made on an individual basis through a multidisciplinary approach.

Factors affecting length of stay in hospital of patients with traumatic spinal cord injury in China.

OBJECTIVE: To investigate factors associated with length of stay in hospital of patients with traumatic spinal cord injury in China, based on recent data spanning a period of 10 years. METHODS: The study was conducted in the China Rehabilitation Research Center, Beijing, which is the largest rehabilitation hospital in China. Associated variables were statistically analysed, including sex, age, marital status, patient's home address, and payment method as demographic variables, and cause of injury, severity of injury, level of injury, spasticity, osteoporosis, neurogenic bladder, and complications as clinical variables. Univariate analysis and multiple linear regression analysis were used to determine the association between length of stay and these var-iables. RESULTS: A total of 2,110 participants were included in this study. Median length of stay in hospital was 113.5 days. Longer length of stay correlated significantly with higher age, single status, being struck by an object, motor vehicle collision, complete injury, and complications. Patients whose injury resulted from a fall from a low height, those with neurogenic bladder, and/or patients of older age had shorter lengths of stay. CONCLUSION: Analysis of data for patients with traumatic spinal cord injury, spanning a recent period of 10 years in China, shows that close attention should be paid to those patients with osteoporosis, spasticity, complete injury, injury caused by object striking or motor vehicle collision, patients with single status, or who are in the age range 15-29 years. Active measures should be taken to reduce length of stay in patients with complications, such as urinary tract infection, respiratory infection, or neuropathic pain.

Ischemic damage may play an important role in spinal cord injury during dancing.

STUDY DESIGN: Retrospective analysis. SETTING: China Rehabilitation Research Center, Beijing, China. OBJECTIVE: To explore possible mechanisms underlying spinal cord injury (SCI) in children caused by hyperextension of the spine while dancing. METHODS: The clinical records of 88 children with SCI (mean age, 5.97 years; age range, 4-10 years) admitted to our hospital from January 1989 to October 2019 were retrospectively reviewed. Computed tomography and magnetic resonance imaging were performed on the day of injury. The time from injury to development of paralysis, as well as post-injury activities were surveyed, while abnormal patterns on images, the range of the involved vertebrae, and the extents of edema and atrophy were assessed. RESULTS: Among the 88 patients, 6 (6.8%) were unable to move immediately after SCI, while paralysis occurred in 42, 23, and 17 patients at <30, 30-60, and >60 min after SCI, respectively. The neurological level of injury of 84 patients was between T4 and T12. On sagittal T2-weighted images (T2WIs), the longitudinal range of spinal cord edema was more than one vertebral body in 65 patients, while spinal cord atrophy below T8 was found in 40 patients. On axial T2WIs, although three patients had none, long T2 signals were found in the central gray matter of seven patients. Meanwhile, necrosis of the central area combined with the peripheral white matter was observed in 57 patients, while three patients had total involvement on a cross section. CONCLUSION: Ischemia-related damage, rather than direct trauma to the spinal cord, may play an important role in SCI due to spinal hyperextension during dancing.

Heterogeneity among traumatic spinal cord injuries at the thoracolumbar junction: helping select patients for clinical trials.

STUDY DESIGN: Retrospective analysis. SETTING: China Rehabilitation Research Center, Beijing, China. OBJECTIVE: A retrospective study that documents the modalities and clarifies the heterogeneity among spinal cord injuries (SCIs) caused by trauma to the thoracolumbar vertebral junction. METHODS: X-ray and MRI imaging, neurological records, and the urodynamics results of 190 patients were reviewed and used to categorize different SCI modalities. First, injuries were divided into complete and incomplete injuries using the International Standard for Neurological Classification of Spinal Cord Injury. Next, the complete injuries were further grouped using the neurological level of injury and Long T2 signal from mid-sagittal MRI images, whereas the bulboconvernosus reflexes were also used as a reference to detect injury to the sacral cord. RESULTS: The SCI modalities were classified into five categories: pure complete epiconus lesion with caudal cord intact (G1), complete epiconus injury with conus medullaris (CM) totally involved in the lesion (G2), CM syndrome, cauda equine syndrome without sacral sparing (G3 and G4), and incomplete injury (G5). CONCLUSIONS: The heterogeneity of SCIs at the thoracolumbar junction was documented, a criterion we propose to be of great significance when selecting patients for clinical trials. In particular, the G2 group, which comprises nearly one third of the patients with epiconus lesions, is sometimes mistaken as G1, an observation that has thus far received insufficient attention.

A method of velocity estimation using composite hyperbolic frequency-modulated signals in active sonar.

This paper proposes a method to estimate the target velocity using a combination of two hyperbolic frequency-modulated (HFM) signals. The Doppler-shifted time-delay between the two signals compared with the original time-delay is used to estimate the target velocity. One finds that a HFM with an increasing frequency sweep (positive HFM) and one with a decreasing frequency sweep (negative HFM) yield a different time. And a better Doppler estimation can be obtained by using a negative HFM signal followed by a positive HFM signal than the other way around. The method is applied to real data and performance is demonstrated via simulated data.

Clinical Predictors of Neurological Outcome within 72 h after Traumatic Cervical Spinal Cord Injury.

To investigate the prognostic values of clinical factors 72 h within traumatic cervical spinal cord injury (TCSCI). Data were extracted from the medical materials of 57 TCSCI cases. AIS was used as the outcome measure and divided into dichotomous variables by two methods, i.e. "complete(AIS = A)/incomplete(AIS ≠ A) SCI" and "motor complete(AIS = A or B)/incomplete(AIS ≠ A and B) SCI". Relationships between evaluated factors and outcomes were investigated by univariate and multivariate methods. MRI Cord transection (MCT) cases, most significantly related to complete SCIs by univariate analysis (P = 0.006), all showed complete SCIs when discharged, which makes it unsuitable for logistic regression. With MCT cases removed, univariate analysis was conducted again, then logistic regression. At last, only C5 spine injury (P = 0.024, OR = 0.241) was related to complete SCI. Cases with compression flexion injury mechanism (CFIM), most significantly related to motor complete SCIs by univariate analysis (P = 0.001), was also unsuitable for logistic regression for the same reason. At last, C3 spine injury (P = 0.033, OR = 0.068) and high energy injury (P = 0.033, OR = 14.763) were related to motor complete SCIs with CFIM cases removed. The results show that MCT and C5 spine injury are good predictors for complete/incomplete SCIs. CFIM, C3 spine injury and high energy injury are good predictors for motor complete/incomplete SCIs.

Rehabilitation for patients with paraplegia and lower extremity amputation.

[Purpose] To study the characteristics and treatment strategy for patients with paraplegia and lower extremity amputation. [Subjects] Six cases were selected from among the patients admitted to the China Rehabilitation Research Center from 1991 to 2014. The criteria for the six cases were spinal cord injury with amputation immediately or in a short time (1 week) after the trauma. [Methods] General information, clinical diagnosis, treatment, rehabilitation and other data were analyzed. [Results] All the six cases were injured by high energy or complex energy accidents: two cases by falls after high voltage electric shock, one by an oil pipeline explosion, one by the impact of a falling tower crane and received high energy traffic accident injuries (one was hit by a train, and the other was hit by a truck at high speed). All the six cases had thoracic and lumbar vertebral injuries and complete paraplegia. Amputation stump infection occurred in four cases. After comprehensive rehabilitation treatment, patients' functional independence measure (FIM) scores improved significantly, but American Spinal Injury Association (ASIA) scores and ASIA Impairment Scale (AIS) grades showed no significant improvement. [Conclusion] When formulating the clinical treatment and rehabilitation for spinal cord injury with amputation patients, simultaneous consideration of the characteristics of the spinal cord injury and amputation is needed to develop an individualized strategy. For spinal cord injury with limb amputation patients, prostheses should allow the improvement of patients' self-care ability.

[RECONSTRUCTION OF LOWER EXTREMITY FUNCTION OF COMPLETE SPINAL CORD INJURY RATS BY FIRST NEURON CONNECTION].

OBJECTIVE: To investigate the effects of the first neuron connection for the reconstruction of lower extremity function of complete spinal cord injury rats. METHODS: Forty adult female Sprague Dawley rats of 300-350 g in weight were selected to prepare the models of L1 transverse spinal cord injury. After 2 weeks of establishing model, the rats were randomly divided into control group (n = 20) and experimental group (n = 20). In the experimental group, the right hind limb function was reconstructed directly by the first neuron; in the control group, the other treatments were the same to the experimental group except that the distal tibial nerve and the proximal femoral nerve were not sutured. The recovery of motor function of lower extremity was observed by the Basso-Beattie-Bresnahan (BBB) scoring system on bilateral hind limbs at 7, 30, 50, and 70 days after operation. The changes of the spinal cord were observed by HE staining, neurofilament 200 immunohistochemistry staining, and the technique of horseradish peroxidase (HRP) tracing. RESULTS: After establishing models, 6 rats died. The right hind limb had no obvious recovery of the motor function, with the BBB score of 0 in 2 groups; the left hind limb motor function was recovered in different degrees, and there was no significant difference in BBB score between 2 groups (P > 0.05). In the experimental group, HE staining showed that the spinal cord was reconstructed with the sciatic nerve, which was embedded in the spinal cord, and the sciatic nerve membrane was clearly identified, and there was no obvious atrophy in the connecting part of the spinal cord. In the experimental group, the expression of nerve fiber was stained with immunohistochemistry, and the axons of the spinal cord were positively by stained and the peripheral nerve was connected with the spinal cord. HRP labelled synapses were detected by HRP retrograde tracing in the experimental group, while there was no HRP labelled synapse in the control group. CONCLUSION: Direct reconstruction of the first neurons is sufficient in the regeneration of corresponding neural circuit by the growth of residual axon; but the motor function recovery of the target muscles innervated by peripheral nerve is not observed.

Characteristics and rehabilitation for patients with spinal cord stab injury.

[Purpose] The objective of the study was to compare the incidence, diagnosis, treatment, and prognosis of patients with spinal cord stab injury to those with the more common spinal cord contusion injury. [Subjects] Of patients hospitalized in China Rehabilitation Research Center from 1994 to 2014, 40 of those having a spinal cord stab injury and 50 with spinal cord contusion were selected. [Methods] The data of all patients were analyzed retrospectively. The cases were evaluated by collecting admission and discharge ASIA (American Spinal Injury Association) and ADL (activity of daily living) scores. [Results] After a comprehensive rehabilitation program, ASIA and ADL scores of patients having both spinal cord stab injury and spinal cord contusion significantly increase. However, the increases were noted to be higher in patients having a spinal cord stab injury than those having spinal cord contusion. [Conclusion] Comprehensive rehabilitation is effective both for patients having spinal cord stab injury and those with spinal cord contusion injury. However, the prognosis of patients having spinal cord stab injury is better than that of patients with spinal cord contusion.

[Research of influence factors on spectral recognition for cotton leaf infected by Verticillium wilt].

Through carrying out spectral test experiment, the influence factors of spectrum test were analyzed, the influence degree of various factors in spectral recognition was explicated and the method of spectra test was optimized for cotton leaf infected by verticillium wilt. The results indicated that under different severity levels, the shape and value of reflectance of disease symptoms part were Significantly higher than healthy part on cotton leaf, compared with the black board as baseboard, the spectral values of disease leaves were slightly higher in visible light wavebands and significantly higher in others wavebands than healthy leaves on white baseboard. Different position of leaf on cotton plant has different effect degree to the recognition of disease, the effect of stem leaf was more obvious than that of else leaf, the identical leaf position was less influenced by disease than band. Test time and cotton varieties had less influence on recognizing disease by spectra, and the effect of the same condition was acceptable. Test site had no effect on disease recognition by spectra. The effect of each factor was different for recognizing disease leaf by spectra, and this study will provide reference for the researchers of crop disease diagnosis by spectra.

Estimation of wheat agronomic parameters using new spectral indices.

Crop agronomic parameters (leaf area index (LAI), nitrogen (N) uptake, total chlorophyll (Chl) content ) are very important for the prediction of crop growth. The objective of this experiment was to investigate whether the wheat LAI, N uptake, and total Chl content could be accurately predicted using spectral indices collected at different stages of wheat growth. Firstly, the product of the optimized soil-adjusted vegetation index and wheat biomass dry weight (OSAVI×BDW) were used to estimate LAI, N uptake, and total Chl content; secondly, BDW was replaced by spectral indices to establish new spectral indices (OSAVI×OSAVI, OSAVI×SIPI, OSAVI×CIred edge, OSAVI×CIgreen mode and OSAVI×EVI2); finally, we used the new spectral indices for estimating LAI, N uptake, and total Chl content. The results showed that the new spectral indices could be used to accurately estimate LAI, N uptake, and total Chl content. The highest R(2) and the lowest RMSEs were 0.711 and 0.78 (OSAVI×EVI2), 0.785 and 3.98 g/m(2) (OSAVI×CIred edge) and 0.846 and 0.65 g/m(2) (OSAVI×CIred edge) for LAI, nitrogen uptake and total Chl content, respectively. The new spectral indices performed better than the OSAVI alone, and the problems of a lack of sensitivity at earlier growth stages and saturation at later growth stages, which are typically associated with the OSAVI, were improved. The overall results indicated that this new spectral indices provided the best approximation for the estimation of agronomic indices for all growth stages of wheat.

[Estimated nitrogen nutrition index based on the hyperspectral for wheat of drip irrigation under mulch].

The accurate wheat management needs a reasonable nitrogen application, and it is one of the key measures for real-time and quantitatively monitoring of nitrogen status to gain the higher yield of wheat. In the present study, two field experiments were conducted with different nitrogen stress and wheat cultivars, the relationship was analyzed between spectral parameters and the partial factor productivity from applied N (PFPn), and the estimating model was established for PFP, in the growth stages of wheat. The result indicated that there was a highly significant correlation between the PFP, and GreenNDVI at jointing, the correlation coefficient (r) was 0.6404, the estimating model of PFPn was established, and the root mean square errors (RMSE) was 0.4597. The result indicated that the PFPn can be effectively estimated by using spectral parameters.