Light-harvesting regulation from leaf to molecule with the emphasis on rapid changes in antenna size.

In the sunlight-fluctuating environment, plants often encounter both light-deficiency and light-excess cases. Therefore, regulation of light harvesting is absolutely essential for photosynthesis in order to maximize light utilization at low light and avoid photodamage of the photosynthetic apparatus at high light. Plants have developed a series of strategies of light-harvesting regulation during evolution. These strategies include rapid responses such as leaf movement and chloroplast movement, state transitions, and reversible dissociation of some light-harvesting complex of the photosystem II (LHCIIs) from PSII core complexes, and slow acclimation strategies such as changes in the protein abundance of light-harvesting antenna and modifications of leaf morphology, structure, and compositions. This review discusses successively these strategies and focuses on the rapid change in antenna size, namely reversible dissociation of some peripheral light-harvesting antennas (LHCIIs) from PSII core complex. It is involved in protective role and species dependence of the dissociation, differences between the dissociation and state transitions, relationship between the dissociation and thylakoid protein phosphorylation, and possible mechanism for thermal dissipation by the dissociated LHCIIs.

Effective volume of ropivacaine 0.75% through a catheter required for interscalene brachial plexus blockade.

BACKGROUND: Ultrasound guidance during peripheral nerve blocks has allowed for reduction in dose and volume of local anesthetic required to accomplish successful blockade using multiple injections through a needle. The authors undertook this study to determine the minimal effective volume required to accomplish successful interscalene brachial plexus block (ISB) through the catheter. METHODS: After obtaining institutional ethics committee approval and written informed consent, patients aged 18-75 yr and scheduled for arthroscopic shoulder surgery under ISB were enrolled. All patients using a step-up/step-down method and the starting dose of 15 ml of 0.75% ropivacaine received an ultrasound-guided ISB catheter. The injection volume was increased or decreased by 1 ml in case of block failure or block success, respectively. RESULTS: The authors found that the proportion of patients with successful blockade increased sharply from approximately 57% at 6 ml to 100% by 7 ml, indicating that a small increase in volume of ropivacaine 0.75% markedly affects the success rate. A total of 12 ISB with injection volume less than 7 ml resulted in successful anesthesia within 30 min, yielding an ED95 of 7 ml (95% CI 6.8-7.2) ropivacaine 0.75%. For the group as a whole, the median (min-max) sensory block onset time was 5 (5-20) min, the median (min-max) motor blocks for the biceps and the deltoid muscles were 7.5 (5-15) min and 10 (5-15) min, respectively. The median (min-max) block duration was 8.9 (3-15) h. CONCLUSIONS: An injection of a minimum of 7 ml of ropivacaine 0.75% through the catheter is required for success rate and timely onset of surgical anesthesia with ISB.

Continuous interscalene block in patients having outpatient rotator cuff repair surgery: a prospective randomized trial.

BACKGROUND: We performed this randomized trial to compare the recovery profile of patients receiving single injection (SISB) and continuous interscalene brachial plexus block (CISB) or general anesthesia (GA) for arthroscopic rotator cuff repair surgery through the first postoperative week. Our primary hypothesis was that the highest pain numeric rating scale (NRS) (worst pain score) at the end of the study week would be lower for patients in the CISB group than for patients in the SISB or GA groups. METHODS: Seventy-one patients scheduled for elective outpatient arthroscopic rotator cuff repair were enrolled. CISB patients received 20 mL of 0.5% ropivacaine as a bolus through a catheter, whereas SISB patients received the same injection volume through a needle. CISB patients received an infusion of 0.2% ropivacaine at 5 mL/h with a patient-controlled bolus of 5 mL hourly for 48 hours. GA-only patients received a standardized general anesthetic. Postoperative highest NRS pain scores through the first postoperative week, time-to-first pain, analgesic consumption, fast-tracked postoperative anesthesia care unit (PACU) bypass rate, length of PACU stay, time-to-discharge home, total hours of sleep, and related adverse effects were recorded in the PACU and at home on postoperative days 1, 2, 3, and 7. RESULTS: No patient in the CISB or SISB groups reported a NRS ≥1 or required analgesics while in the PACU. While most patients in the CISB and SISB groups were fast-tracked to PACU discharge, no patient in the GA group was fast-tracked (Χ P = 0.003). Length of stay in the PACU was significantly shorter for the CISB and SISB groups than for the GA group (20 ± 31, 30 ± 42, and 165 ± 118 minutes, respectively (CISB vs GA, P < 0.001; SISB vs GA, P <0.001), and time-to-discharge home was significantly shorter when compared with the GA group. Time to first pain report was longer in the CISB group. Mean NRS scores were lower for patients in the CISB group than in the SISB and GA groups on postoperative days 1 and 2, and use of narcotics (doses ≥1) was lower until postoperative day 3. Patients who received CISB slept significantly longer than patients who received SISB or GA (P < 0.01) during the first 48 hours postoperatively. By the end of the study week, 26% of patients in the CISB group, 83% in the SISB group, and 58% of GA patients reported NRS ≥4 (both P-values ≤ 0.05). CONCLUSION: The analgesic benefits of CISB found in the PACU and immediately after discharge extend through the intermediate recovery period ending on postoperative day 7.

The sequence of administration of 1.5% mepivacaine and 0.5% bupivacaine does not affect latency of block onset or duration of analgesia in ultrasound-guided interscalene block.

BACKGROUND: During peripheral nerve blockade, different local anesthetics may be sequentially administered. Typically, a short- or intermediate-acting local anesthetic is administered before a long-acting local anesthetic to achieve a block with rapid onset and long duration. However, there is a paucity of data on advantages of such sequencing. We hypothesized that when using a sequential mixture of mepivacaine and bupivacaine for ultrasound-guided interscalene block, the order of injection of the drugs does not influence the clinical characteristics of the block achieved. METHODS: Sixty-four patients undergoing arthroscopic shoulder surgery (aged 18-65 years; ASA physical status I-II) with a single-injection ultrasound-guided interscalene brachial plexus block as sole anesthetic were studied. The subjects were randomized to receive 1 of 2 local anesthetic sequences: 15 mL of mepivacaine 1.5% followed by 15 mL of bupivacaine 0.5% (group A), or the same local anesthetics in the reverse order (group B). The durations of sensory and motor block were the primary outcomes. Block onset was also assessed. RESULTS: Duration of motor block was similar between group A and group B (10.1 ± 4.7 hours vs 10.3 ± 5.1 hours, mean difference 0.2 hours, 95% confidence interval [CI] -3.3 to 2.9, P = 0.9). Duration of analgesia was also similar between group A and group B (9.5 ± 5.6 hours vs 10.2 ± 4.5 hours, mean difference 0.7 hours, 95% CI -3.2 to 1.9, P = 0.42). Onset of sensory block was similar between the 2 groups (15.9 ± 7.1 minutes for group A, 13.9 ± 7.0 minutes for group B, mean difference 1.9 minutes, 95% CI -1.4 to 5.2, P = 0.25). CONCLUSIONS: The sequence in which 15 mL mepivacaine 1.5% and 15 mL bupivacaine 0.5% are administered does not seem to have a clinically meaningful effect on duration or onset of ultrasound-guided interscalene brachial plexus block.

The effect of mixing 1.5% mepivacaine and 0.5% bupivacaine on duration of analgesia and latency of block onset in ultrasound-guided interscalene block.

BACKGROUND: Short- and long-acting local anesthetics are commonly mixed to achieve nerve blocks with short onset and long duration. However, there is a paucity of data on advantages of such mixtures. We hypothesized that a mixture of mepivacaine and bupivacaine results in a faster onset than does bupivacaine and in a longer duration of blockade than does mepivacaine. METHODS: Sixty-four patients undergoing arthroscopic shoulder surgery (ages 18 to 65 years; ASA physical status I-II) with ultrasound-guided interscalene brachial plexus block as the sole anesthetic were studied. The subjects were randomized to receive 1 of 3 study solutions: 30 mL of mepivacaine 1.5%, 30 mL of bupivacaine 0.5%, or a mixture of 15 mL each of bupivacaine 0.5% and mepivacaine 1.5%. The block onset time and duration of motor and sensory block were assessed. RESULTS: Onset of sensory block in the axillary nerve distribution (superior trunk) was similar among the 3 groups (8.7 ± 4.3 minutes for mepivacaine, 10.0 ± 5.1 minutes for bupivacaine, and 11.3 ± 5.3 minutes for the combination group; P = 0.21 between all groups). The duration of motor block for the combination group (11.5 ± 4.7 hours) was between that of the bupivacaine (16.4 ± 9.4 hours) and mepivacaine (6.0 ± 4.2 hours) groups (P = 0.03 between bupivacaine and combination groups; P = 0.01 between mepivacaine and combination groups). Duration of analgesia was the shortest with mepivacaine (4.9 ± 2.4 hours), longest with bupivacaine (14.0 ± 6.2 hours), and intermediate with the combination group (10.3 ± 4.9 hours) (P < 0.001 for mepivacaine vs. combination group; P = 0.01 for bupivacaine vs. combination group). CONCLUSIONS: For ultrasound-guided interscalene block, a combination of mepivacaine 1.5% and bupivacaine 0.5% results in a block onset similar to either local anesthetic alone. The mean duration of blockade with a mepivacaine-bupivacaine mixture was significantly longer than block with mepivacaine 1.5% alone but significantly shorter than the block with bupivacaine 0.5% alone.

The minimum effective anesthetic volume of 0.75% ropivacaine in ultrasound-guided interscalene brachial plexus block.

BACKGROUND: The use of ultrasound to monitor needle placement and spread of local anesthetics (LA) has allowed reductions in the volume of LA required to anesthetize peripheral nerves. In the current study we investigated the minimal volume necessary to accomplish surgical anesthesia with interscalene brachial plexus block. METHODS: Twenty ASA physical status I-III patients, ages 18 to 75 years and scheduled for shoulder surgery under interscalene brachial plexus block, were enrolled. Using a previously validated step-up/step-down method, we determined the injection volume of 0.75% ropivacaine used for consecutive patients by the outcome of the preceding block. The starting volume was 15 mL (3 injections of 5 mL per each trunk); in the case of block failure, the volume was increased by 1 mL, whereas after successful block, the volume was reduced by 1 mL. The study was stopped upon achieving the secondary stopping rule of 10 consecutive successful interscalane blocks using 5 mL of ropivacaine 0.75%. Successful surgical anesthesia with the brachial plexus block was defined as presence of adequate motor block (motor score of ≤2 on 0 to 4 scale), absent sensation to cold and pinprick sensation within 30 minutes of injection, and absence of the need for general anesthesia for completion of surgery. Duration of sensory blockade was assessed by asking the patient to record the time of first pain sensation. RESULTS: Under our study conditions, successful surgical anesthesia for arthroscopic shoulder surgery can be achieved with 5 mL of 0.75% ropivacaine, or approximately 1.7 mL per each of the 3 trunks of the brachial plexus (superior, middle, and inferior). The study was stopped after 10 consecutive successful blocks with 5 mL of LA (100%, 95% confidence interval [CI]: 74.1%-100%). For the group as a whole, the median (range) sensory block onset time was 5 (5-20) minutes, the median (range) motor block for the biceps was 7.5 (5-15) minutes, and for abduction 10 (5-15) minutes. The median (range) block duration was 9.9 (5-19) hours, and the mean (SD) block performance time was 8.0 ± 3.2 minutes. Mean duration of analgesia was 9.9 ± 3.7 hours. Duration of analgesia was not associated with volume of LA (r = 0.05, P = 0.83). CONCLUSIONS: All patients in our study had successful surgical blocks with 5 mL of LA. However, the lower limit of the CI (calculated on the assumption of a single failure) does include the possibility of a 25% failure rate; thus studies using similar stopping rules for doses higher than 5 mL are nonetheless warranted.

A new tool measuring oral malodor quality of life.

A valid measure of oral malodor (halitosis) and associated quality of life is required for the complete assessment of treatment effectiveness. The purpose of this study was to analyze the psychometric and clinimetric validity of the Halitosis Associated Life-quality Test (HALT) questionnaire, a specific 20-item quality-of-life measure for halitosis. The HALT is a de novo designed tool based on patient interviews and literature review. The University Hospital was the setting for the prospective random non-controlled study design. The comparison between the evaluator' scales on organoleptic testing and HALT scores was performed during the patient's initial visit. HALT was completed by 33 and 16 patients at the initial visit and at 3 months after treatment commencement, respectively. Two treatment arms comprising an experimental arm including Caphosol rinse for xerostomia-associated halitosis, and an established treatment arm with laser cryptolysis were compared. Cronbach's α was 0.93; coefficient alpha with deleted variables was between 0.92 and 0.94; equal length Spearman-Brown coefficient is 0.95. The Cronbach's alphas of each split questionnaire were 0.85 and 0.88, respectively, and test-retest scores were highly correlated (r = 0.85). HALT scores were significantly associated with the scales of organoleptic test (F = 118, p < 0.001; r = 0.96, p < 0.001). HALT successfully measured each treatment arm and showed improvement (p < 0.002) in both arms. Although cryptolysis was more efficacious, the encouraging results of the Caphosol arm indicate that additional investigation is warranted. HALT proved a valid outcome measure for patients with halitosis, describes its burden and is sensitive to clinical change.

Reversible association of ribulose-1, 5-bisphosphate carboxylase/oxygenase activase with the thylakoid membrane depends upon the ATP level and pH in rice without heat stress.

Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) in the thylakoid membrane (TM) has been shown to play a role in protection and regulation of photosynthesis under moderate heat stress. However, the physiological significance of RCA bound to the TM (TM-RCA) without heat stress remains unknown. In this study, it is first shown, using experiments in vivo, that the TM-RCA varies in rice leaves at different development stages, under different environmental conditions, and in a rice mutant. Furthermore, it is shown that the amount of TM-RCA always increased when the Rubisco activation state and the pH gradient across the TM (DeltapH) decreased. It was then demonstrated in vitro that the RCA bound dynamically to TM and the amount of TM-RCA increased during Rubisco activation. A high level of ATP and a high pH value promoted the dissociation of RCA from the TM. Both the RCA association with and dissociation from the TM showed conformational changes related to the ATP level or pH as indicated by the changes in fluorescence intensity of 1-anilinonaphthalene-8-sulphonic acid (ANS) binding to RCA. These results suggest that the reversible association of RCA with the TM is ATP and pH (or DeltapH) dependent; it might be involved in the RCA activation of Rubisco, in addition to the previously discovered role in the protection and regulation of photosynthesis under heat stress.

Intraneural injection with low-current stimulation during popliteal sciatic nerve block.

BACKGROUND: Prevention of an intraneural injection of a local anesthetic during peripheral nerve blockade is considered important to avoid neurologic injury. However, the needle-nerve relationship during low-current electrical nerve localization is not well understood. METHODS: We postulated that intraneural needletip location is common during low-current stimulation popliteal sciatic nerve blockade. Twenty-four consecutive ASA class I-III patients scheduled for foot or ankle surgery under popliteal sciatic nerve block using a combined ultrasound and nerve stimulator-guided technique were prospectively studied. The end point for needle advancement was predetermined to be either an elicited motor response between 0.2 and 0.5 mA (100 mus/2 Hz) or an apparent intraneural location of the needletip as seen on ultrasound, whichever came first. The injection occurred at either end points provided the injection pressure was <20 psi. The injection was considered intraneural when injectate resulted in both the swelling and compartmentalization of the nerve within the epineurium. RESULTS: Elicited motor response could be obtained only upon entry of the needle into the intraneural space in 20 patients (83.3%). In the remaining four patients (16.7%), a motor response with a stimulating current of 1.5 mA could not be obtained even after the needle entry into the intraneural space. An injection in the intraneural space occurred in all patients who had motor-evoked response at current 0.2-0.4 mA. All 24 blocks resulted in adequate anesthesia for foot surgery. No patient developed postoperative neurologic dysfunction. CONCLUSION: The absence of motor response to nerve stimulation during popliteal sciatic nerve block does not exclude intraneural needle placement and may lead to additional unnecessary attempts at nerve localization. Additionally, low-current stimulation was associated with a high frequency of intraneural needle placement.

Lumbar plexus block using high-pressure injection leads to contralateral and epidural spread.

BACKGROUND: The main advantage of lumbar plexus block over neuraxial anesthesia is unilateral blockade; however, the relatively common occurrence of bilateral spread (up to 27%) makes this advantage unpredictable. The authors hypothesized that high injection pressures during lumbar plexus block carry a higher risk of bilateral or neuraxial anesthesia. METHODS: Eighty patients undergoing knee arthroscopy (age 18-65 yr; American Society of Anesthesiologists physical status I or II) during a standard, nerve stimulator-guided lumbar plexus block using 35 ml mepivacaine, 1.5%, were scheduled to be studied. Patients were randomly assigned to receive either a low-pressure (< 15 psi) or a high-pressure (> 20 psi) injection, as assessed by an inline injection pressure monitor (BSmart; Concert Medical LLC, Norwell, MA). The block success rate and the presence of bilateral sensory and/or motor blockade were assessed. RESULTS: An interim analysis was performed at n = 20 after an unexpectedly high number of patients had neuraxial spread, necessitating early termination of the study. Five of 10 patients (50%) in the high-pressure group had a neuraxial block with a dermatomal sensory level T10 or higher. In contrast, no patient in the low-pressure group (n = 10) had evidence of neuraxial spread. Moreover, 6 patients (60%) in the high-pressure group demonstrated bilateral sensory blockade in the femoral distribution, whereas no patient in the low-pressure group had evidence of a bilateral femoral block. CONCLUSIONS: Injection of local anesthetic with high injection pressure (> 20 psi) during lumbar plexus block commonly results in unwanted bilateral blockade and is associated with high risk of neuraxial blockade.

An ultrasonographic and histological study of intraneural injection and electrical stimulation in pigs.

BACKGROUND: In this study we evaluated the minimum stimulating current associated with intraneural needle placement and sonographic appearance of intraneural injection. METHODS: We inserted a needle 2 cm inside 28 pig nerves (brachial plexus in vivo), recorded the minimum current to elicit a motor response, and injected dye (5 mL) under ultrasound (US) imaging. RESULTS: The minimum current to elicit a motor response was 0.43 mA (range: 0.12-1.8 mA). Nerve expansion was visualized by US in 24 of 28 nerves. Histology revealed penetration of the epineurium in these same 24 nerves. There was no evidence of dysplasia within the fascicle of any nerve. CONCLUSIONS: US may prove useful to detect intraneural injection, whereas a motor response above 0.5 mA may not exclude intraneural needle placement. The correlation between intraneural injection and neurological dysfunction remains unclear.

Ultrasound examination of peripheral nerves in the forearm.

BACKGROUND AND OBJECTIVES: We examined in a volunteer population whether nerves in the forearm could be seen consistently using ultrasound imaging and whether this new information could have implications for the way we perform regional anesthesia of the median, radial, and ulnar nerves. METHODS: Eleven volunteers underwent ultrasound examination of both forearms. The median, ulnar, and radial nerves were followed and images were obtained at the elbow, proximal forearm, mid forearm, distal forearm and wrist levels. In addition the radial nerve was followed proximally to a point 5 cm above the elbow. Images were compared for consistency of location of the nerves and depth from skin and width was calculated for each nerve at each level. RESULTS: Anatomy of each nerve was consistent except for one forearm where the median nerve was lateral to the brachial artery at the elbow and one forearm where a superficial ulnar artery only joined the ulnar nerve at the wrist. A convenient location for blockade of both median and ulnar nerves is the midforearm combining ease of visualization, ability to block all terminal branches and minimal potential for vascular injury. The radial nerve is seen most easily at the elbow although blockade of the superficial radial nerve may spare radial motor function. CONCLUSIONS: Nerves in the forearm are consistently located using ultrasound. Further confirmation in clinical practice is required.

Disclosure of risks associated with regional anesthesia: a survey of academic regional anesthesiologists.

BACKGROUND AND OBJECTIVES: In view of the relatively few large studies available to estimate the rates of complications following regional anesthesia, we aimed to identify and quantify the risks that academic regional anesthesiologists and regional anesthesia fellows disclose to their patients before performing central and peripheral nerve blockade. METHODS: We asked 23 North American regional anesthesia fellowship program directors to distribute a questionnaire to the regional anesthesiologists and regional anesthesia fellows at their institutions. The questionnaire was designed to capture the risks and corresponding incidences that are routinely disclosed to patients before performing the most common central and peripheral nerve block techniques. RESULTS: The total number of respondents was 79 from 12 different institutions. Fifty-eight (74%) respondents disclose risks of regional anesthesia in order to allow their patients to make an informed choice, whereas 20 (26%) disclose risks for medicolegal reasons. For central neural blockade, the most commonly disclosed risks are headache, local pain/discomfort, and infection. For peripheral nerve blockade, the most commonly disclosed risks are transient neuropathy, local pain/discomfort, and infection. For both central and peripheral nerve blockade, the risks most commonly disclosed are also those with the highest-reported incidences. CONCLUSIONS: The risks of regional anesthesia most commonly disclosed to patients by academic regional anesthesiologists and regional anesthesia fellows are benign in nature and occur frequently. Severe complications of regional anesthesia are far less commonly disclosed. The incidences of severe complications disclosed by academic regional anesthesiologists and their fellows can be inconsistent with those cited in the contemporary literature.

[The mechanisms of plant photosynthetic acclimation to elevated CO2 concentration].

When measured at a same CO(2) concentration, net photosynthetic rate is often significantly lower in long-term high CO(2)-grown plants than the ambient CO(2)-grown ones. This phenomenon is termed photosynthetic acclimation or down-regulation. Although there have been many reports and reviews, the mechanism(s) of the photosynthetic acclimation is not very clear. Combining the work of the authors' group, this paper briefly reviews the progress in studies on the mechanism(s) of the photosynthetic acclimation to elevated CO(2). It is suggested that besides the possible effects of respiration enhancement and excessive photosynthate accumulation, RuBP carboxylation limitation and RuBP regeneration limitation are probably the main factors leading to the photosynthetic acclimation.

[Species-dependence of the pattern of plant photosynthetic rate response to light intensity transition from saturating to limiting one].

By observing the photosynthetic responses of leaves to changes in light intensity and CO(2) concentration it was found that among the more than 50 plant species examined 32 species and 25 species showed respectively the V pattern and L pattern of the photosynthetic response to light intensity transition from saturating to limiting one (Figs.1 and 2 and Table 1). The pattern of photosynthetic response to light intensity transition is species-dependent but not leaf developmental stage-dependent (Fig.3). The species-dependence was not related to classification in taxonomy because the photosynthetic response might display the two different patterns (V and L) in plants of the same family, for example, rice and wheat (Gramineae), soybean and peanut (Leguminosae). It seemed to be related to the pathway of photosynthetic carbon assimilation because all of the C(4) plants examined (maize, green bristlegrass and thorny amaranth) displayed the L pattern. It might be related to light environment where the plants originated. The V pattern of photosynthetic response to light intensity transition was often observed in some plants grown in shade habitats, for example, sweet viburnum and Japan fatsia, while the L pattern was frequently observed in those plants grown in sunny habitats, for example, ginkgo and cotton. Furthermore, the ratio of electron transport rate to carboxylation rate in vivo measured at limiting light was far higher in the V pattern plants (mostly higher than 10) than in the L pattern plants (mostly lower than 5), but the ratio measured at saturating light had no significant difference between the two kinds of plants (Table 2). These results can be explained in part by that the V pattern plant species have larger light-harvesting complex (LHCII) and at saturating light the reversible dissociation of some LHCIIs from PSII reaction center complex occurs. The pattern of photosynthetic response to light intensity transition and the ratio of electron transport rate to carboxylation rate in vivo measured at limiting light can probably be used as a criterion to distinguish sun plants from shade plants. In the observation of photosynthetic response to light intensity transition the use of saturating light is very important because using non-saturating light can form an artifact, which leads to incorrect conclusion (Fig.4).

Relationship between grain yield and leaf photosynthetic rate in super hybrid rice.

In order to explore the relationship between grain yield and photosynthesis, the yield composition and leaf photosynthetic rate in some super hybrid rices and ordinary hybrid rice 'Shanyou 63' as control were measured in 2000-2005. The results were as follows. (1) The yield levels of the four super hybrid rices, 'Pei'ai 64S/E32', 'P88S/0293', 'Jin23A/611' and 'GD-1S/RB207', were significantly higher, being 108%-120% of 'Shanyou 63'. (2) These super hybrid rices had a better plant type with more erect upper layer leaves and bigger panicles or more spikelets per panicle, being 125%-177% of spikelets Shanyou 63 spikelets. (3) Net photosynthetic rates of these super hybrid rices were significantly higher in the second leaf but not necessarily in the first leaf or flag leaf than those of spikelets Shanyou 63 spikelets. (4) The removal of half flag leaf led to a decline in the seed-setting rate, while the removal of half panicle induced its increase in spikelets GD-1S/RB207 spikelets. Hence, higher yield in these super hybrid rices can be attributed to their bigger panicles, better plant type and higher light use efficiency of their canopies. Raising the photosynthetic capacity of each leaf, especially flag leaf, is the key to overcome the photosynthate-source restriction on grain yield and to make a new breakthrough of yield potential in future breeding of super hybrid rice.

The sensitivity of motor response to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound.

BACKGROUND AND OBJECTIVE: Seeking paresthesia and obtaining a motor response to an electrical stimulus are the two most common methods of nerve localization for the performance of peripheral-nerve blocks. However, these two endpoints do not always correlate, and the actual sensitivity and specificity of either method remains unknown. The objective of this study is to determine the sensitivity of paresthesia and motor response to electrical nerve stimulation as tools for nerve localization when a 22-gauge insulated needle is used for the performance of axillary-nerve block. METHODS: After IRB approval and informed consent, 103 patients were enrolled. Real-time ultrasonography was used as the reference test. After needle-to-nerve contact was confirmed by ultrasonography, the patient was requested to report the presence of paresthesia, and a nerve stimulator was used to seek a motor response, with a stimulating current of 0.5 mA or less. RESULTS: One patient was excluded from analysis because of protocol violation. Paresthesia was found to be 38.2% sensitive and motor response was 74.5% sensitive for detection of needle-to-nerve contact. CONCLUSION: The very different and relatively low sensitivity of either technique may explain, in part, the lack of correlation previously reported between the 2 endpoints.

[Exploring the observation methods of photosynthetic responses to light and carbon dioxide].

Through observing the responses of photosynthesis in leaves of broad bean grown under natural conditions to light and CO(2) using a portable photosynthetic analyzer LI-6400, the following findings were obtained. (1) Observing the response of photosynthesis to light using a leaf without being induced by light might lead to an artifact that photosynthesis was not saturated even under full sunlight. (2) The calculated saturating light intensity of photosynthesis by some empirical equations was much lower than actual value obtained by observing. (3) During observation of photosynthetic response to CO(2), each step of changing CO(2) concentration should be accompanied by a match step of the photosynthetic analyzer, otherwise, there will be substantial deviations in the results obtained. (4) Observing photosynthetic response to CO(2) at non-saturating light might lead to an underestimation of leaf photosynthetic capacity.