Effectiveness of Autologous Skin Cell Suspension in Large Total Body Surface Area Burns: Analysis of Clinical Outcomes and Patient Charges.

Autologous skin cell suspension (ASCS) is an adjunct to conventional split-thickness skin grafts (STSG) for acute burns, enhancing healing and reducing donor site requirements. This study validates ASCS's predictive benefits in hospital stay reduction and cost savings by analyzing outcomes and real-world charges post-ASCS implementation at a single institution. A retrospective study (2018-2022) included burn patients with ≥10% TBSA. The study population comprised two groups: burns treated either with a combination of ASCS ± STSG or with STSG alone. Outcomes included LOS, surgeries, infection, complications, days on antibiotics, and adjusted charge per TBSA. The ASCS ± STSG group demonstrated significantly shorter LOS (Mdn: 16.0 days, IQR: 10-26) than the STSG group (Mdn: 20.0 days, IQR: 14-36; P = 0.017), and fewer surgeries (Mdn: 1.0, IQR: 1-2) versus the STSG group (Mdn: 1.0, IQR: 1-4; P = 0.020). Postoperative complications were significantly lower in ASCS ± STSG (11% vs. 36%; P < 0.001). The STSG group had a longer distribution of antibiotic days (IQR: 0-7.0, min-max: 0-76) than the ASCS ± STSG group (IQR: 0-0, min-max: 0-37; P = 0.014). Wound infection incidence did not differ (P = 0.843). ASCS ± STSG showed a lower distribution of adjusted charge per TBSA (IQR: $10,788.5 - $28,332.6) compared to the STSG group (IQR: $12,336.8 - $29,507.3; P = 0.602) with a lower mean adjusted charge per TBSA ($20,995.0 vs. $24,882.3), although this was not statistically significant. ASCS ± STSG utilization demonstrated significant reductions in LOS, surgeries, postoperative complications, antibiotics, and potential cost savings. These findings underscore the practicality of integrating ASCS in burn management, offering substantial benefits to patients and healthcare institutions.

Oncologic Staging Computed Tomography with IV Contrast Has Similar Efficacy to Dedicated Computed Tomography Angiography for Preoperative DIEP Flap Planning.

Background: Due to variations in perforator vasculature, deep inferior epigastric artery perforator (DIEP) flap preoperative imaging can minimize operative time required to locate the most suitable perforators. Dedicated computed tomography angiography (CTA) has been the gold standard; however, many patients have already undergone a staging computed tomography (CT) per oncologic workup. The benefits from CTA may also be realized with a staging CT or CT with IV contrast. Methods: Ten patients who underwent DIEP flap reconstruction with staging CT and CTA within 3 years of one another were included in this study. Reviewers evaluated axial views of both imaging modalities separately to identify each visible perforator in reference to the pubic symphysis from the xiphoid to the pubic symphysis. An intraclass correlation coefficient (ICC) was used to determine agreement in location of perforators between the two imaging studies. Statistical analysis was performed using an ICC and Wilcoxon signed rank-tests. Results: The identified perforators within the patient cohort had an excellent correlation between their location on CT and CTA based upon ICC. The mean number of perforators identified in the CT group was 15.3 (SD 4.9) and in the CTA group was 18.8 (SD 6.4), which was not statistically different (P = 0.247). Conclusions: CT has similar efficacy in identifying number of perforators and perforator location to dedicated CTA for preoperative planning in DIEP flaps. This has the potential for decreased patient contrast and ionizing radiation exposure as well as improved patient and healthcare resource utilization.

Comparative results of autologous skin cell suspension combined with a contact layer dressing versus autologous skin cell suspension and a poly-lactic acid dressing in larger total body surface burns.

INTRODUCTION: Contact layer dressing (CLD) is standard after autologous skin cell suspension (ASCS); however, the authors wondered whether a poly-lactic acid dressing (PLAD) results in superior outcomes and cost savings. MATERIAL AND METHODS: Retrospective cohort study including greater than 10% total body surface area (TBSA) burns treated with ASCS and either PLAD or CLD. Primary outcomes were infection and length of stay (LOS). RESULTS: 71 patients (76% male, 24% pediatric, mean age 37 years) were included. Twenty-eight patients (39%) received CLD and 43 (61%) received PLAD. Wound infections were decreased in PLAD (7 vs 32%, p = 0.009). When controlling for area grafted (cm2) and TBSA, logistic regression revealed odds of post-operative infection was 8.1 times higher in CLD (p = 0.015). PLAD required antibiotics for fewer days (mean 0.47 vs 4.39, p = 0.0074) and shorter LOS (mean 17 vs 29 days, p < 0.001). Mean adjusted charges per %TBSA was $18,459 in PLAD vs. $25,397 in CLD (p = 0.0621). CONCLUSION: In the first analysis of its kind, this study showed polylactic acid dressing combined with autologous skin cell suspension led to a decrease in postoperative infections, length of hospital stay, and total patient charges.

Simultaneous second-stage Fowler-Stephens Orchiopexy and microvascular testicular autotransplantation in a patient with prune belly syndrome with cryptorchidism.

We present a case of simultaneous second-stage Fowler-Stephens Orchiopexy (FSO) with microvascular testicular autotransplantation for cryptorchidism and in a patient with prune belly syndrome. At 5 months old, the patient underwent laparoscopic bilateral first-stage FSO with the right testicle located 1 cm from the liver and the left slightly more caudal. An ultrasound on postoperative Day 72 following second-stage FSO and microvascular autotransplantation showed patent testicular vasculature. Our experience shows that this combination technique is safe and effective to supercharge the testicle and augment collateral vessels if clinical suspicion for monotherapy failure is high.

Managing Ulnar Nerve Subluxation With a Medial Intermuscular Septum Sling.

BACKGROUND: Cubital tunnel syndrome (CuTS) is a lifestyle-altering peripheral neuropathy lacking a consensus for optimal surgical management. We describe creation of a fascial "V-sling" without ulnar nerve transposition, which is associated with increased surgical morbidity compared with decompression. The purpose of this study is to evaluate a novel technique with effective ulnar nerve decompression and subluxation prevention by creating a fascial sling in patients with CuTS and ulnar nerve subluxation. METHODS: We reviewed records of 39 elbows in 35 patients who underwent in situ ulnar nerve decompression and creation of a fascial sling in a "V" configuration to stabilize the nerve in its native position. We examined patient demographics, Single Assessment Numeric Evaluation (SANE) scores, Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) scores, and patient outcomes. Chi-square and student's t test were used for all analysis. RESULTS: A total of 37 extremities in 33 patients undergoing nerve decompression had nerve subluxation confirmed intraoperatively. There was a statistically significant change in preoperative and postoperative SANE scores of 64.5 and 82.3, respectively. Mean QuickDASH scores decreased significantly from 49.3 preoperative to 10.8 postoperative. The long-term QuickDASH scores obtained at mean of 564 days were maintained at 10.76. CONCLUSIONS: This study describes a novel technique for treating CuTS by achieving in situ nerve decompression and addressing ulnar nerve subluxation with creation of an intermuscular septal sling. The technique improved functional outcomes and provided symptomatic relief, while avoiding risks commonly associated with nerve transposition.

Role of Prophylactic Sartorius Flaps for Preventing Deep Space Infection in Lower Extremity Revascularization.

Groin infections in vascular surgery are common and compromise the goal of limb preservation. Strategies to prevent deep space infection (DSI) include incision orientation and muscle flaps. Literature evaluating prophylactic flaps preventing DSI is scarce. We aimed to compare prophylactic sartorius flaps to layered closure in preventing readmission for DSI, along with the effect of incision orientation. This was a retrospective study of vascular surgery patients at a single institution with femoral artery exposure from 2017-2021. Patients with active groin infections were excluded. Prophylactic sartorius flaps were compared to those with layered closure regarding 30-day hospital readmission for DSI. Oblique versus vertical incisions was compared regarding the primary outcome. Fifty-three patients received sartorius flaps, and 122 received layered closure. Seventy patients had oblique incisions, and 105 patients had vertical incisions. Sartorius flaps had a higher rate of previous groin surgery compared to layered closure (45.3% vs. 24.7%, p<0.01). Vertical incisions had a higher rate of previous groin surgery (38.1% vs. 20.0%, p<0.02), while oblique incisions had a higher rate of obesity (24.3% vs. 8.6%, p<0.01). There was a lower rate of DSI in sartorius flaps compared to layered closure (1.9% vs. 6.6%, p=2.80), although not statistically significant due to lack of power. There was no difference in DSI in the oblique versus vertical incisions (4.3% and 5.7%, p=0.760). Patients with prophylactic sartorius flaps experienced fewer DSI, although further evaluation with increased sample size is required for adequate study power. We believe sartorius flaps are a simple solution to prevent groin complications.

Immediate Deep Inferior Epigastric Perforator Flap Reconstruction of a Giant Phyllodes Tumor.

We present a case of a giant phyllodes tumor (PT) requiring simple mastectomy with en bloc pectoralis major resection and immediate deep inferior epigastric perforator (DIEP) flap reconstruction. This patient presented with a four-year history of an enlarging breast mass with ultrasound-guided biopsy results consistent with atypical fibroepithelial proliferation that was highly concerning for a borderline phyllodes tumor. In this large, rare breast tumor that required en bloc pectoralis major resection, we describe the novel use of an immediate single pedicled DIEP flap for the resulting chest wall defect. The patient's postoperative course was uncomplicated, and she reported satisfactory cosmetic and functional outcomes at her initial postoperative follow-up visits. Our findings support the use of simple mastectomy with en bloc resection and immediate single-pedicled DIEP flap for the definitive treatment of giant phyllodes tumors. Our experience shows this is a safe and effective technique for achieving adequate oncologic resection while maintaining postoperative function and cosmesis, which are essential for patient quality of life.

Endoscopic electrocauterization for management of chronic perineal sinus following abdominoperineal resection.

We present a case of a chronic perineal sinus following abdominoperineal resection with management via endoscopic electrocauterization. This patient presented with 1 year of bloody, mucus drainage from a perineal wound following abdominoperineal resection for anastomotic leak and stricture from a remote low anterior resection for T2N1 rectal cancer. We describe a novel use of endoscopic electrocautery to debride, de-epithelialize and ultimately eliminate the sinus cavity. The patient's postoperative course was uncomplicated and reported decreased drainage at 2- and 4-week postoperative follow-up. Long-term plans include sequential drain downsizing to facilitate cavity closure. Our findings suggest that endoscopic electrocauterization can safely and effectively reduce chronic perineal sinus drainage to facilitate cavity elimination, while avoiding morbidity associated with more invasive operative interventions.

Precise Analgesic Instructions Improve Narcotic Usage: A Randomized Trial.

BACKGROUND: Given the ongoing battle with opioid abuse and overuse in the United States, new strategies are consistently being implemented to reduce opioid utilization and overprescribing. OBJECTIVES: The purpose of this study was to determine if a more regulated explicit pain management instruction plan could reduce the number of opioids taken. METHODS: Blinded randomized prospective study comparing a total of 110 (Group A = 55, Group B = 55) women who underwent elective outpatient bilateral breast reduction surgery by 2 different plastic surgeons. Patients were randomly divided into either Group A (control) that received general pain management instructions or Group B (experimental) that received explicit pain management instructions from the surgeons and nurses. Participants were asked to record the number of times they treated their pain with each separate modality. They were also asked to record their average daily pain scale for the days that they were treating their pain. RESULTS: Patients in Group B took on average 1.5 oxycodone (5 mg) and patients in Group A took on average 5.7 oxycodone (5 mg) (P < 0.01). Thirty-four patients in Group B took no oxycodone. Patients in Group B also had statistically significant lower subjective pain scores. CONCLUSIONS: Based on these results, it appears that standardizing how patients are instructed to treat their pain postoperatively may reduce the number of narcotics needed, thus reducing the number of narcotics prescribed without compromising pain control.

Music Augmented With Isochronic Auditory Beats or Vibrotactile Stimulation Does Not Affect Subsequent Ergometer Cycling Performance: A Pilot Study.

Methods to enhance the ergogenic effects of music are of interest to athletes of all abilities. The aim of this pilot study was to investigate the ergogenic effects of two commercially available methods of music augmentation: auditory beats and vibrotactile stimulation. Six male and five female cyclists/triathletes cycled for 7 minutes at three different intensities: a rate of perceived exertion (RPE) of 11 ("light"), RPE of 15 ("hard"), and a 7-minute time-trial. Before each 7-minute bout of cycling, participants listened to 10 minutes of self-selected music (MUS), or the same music with the addition of either isochronic auditory beats (ABS) or vibrotactile stimulation via SUBPACTM (VIB). MUS, ABS and VIB trials were performed in a randomized order. Power output was measured during cycling and felt arousal and feeling scores were recorded at timepoints throughout the protocol. The results found the augmented MUS interventions did not influence power output with no significant main effect of trial (p = 0.44, η2 = 0.09) or trial × cycling intensity interaction (p = 0.11, η2 = 0.20). Similarly, both felt arousal and feeling scores were unchanged between the MUS, ABS, and VIB trials (p > 0.05). In conclusion, this pilot study indicated an ineffectiveness of the ABS and VIB to affect subsequent 7-min cycling performance compared to self-selected MUS alone.

Primary Peritoneal Carcinosarcoma: A Case Report.

Introduction: Carcinosarcoma, also known as malignant mixed Mullerian tumor (MMMT) is a malignant biphasic neoplasm consisting of carcinomatous and malignant non-epithelial components of mesenchymal origin. MMMTs typically arise from the female genital tract in patients over 40 years old. Primary extragenital MMMTs are extremely rare with published literature totaling 40 reported cases. The primary peritoneal carcinosarcoma is an aggressive tumor as patients with this tumor have an average survival of 7.6 months. Surgical debulking is the mainstay of treatment for these tumors and systemic chemotherapy is advised in all cases. Case: A 48-year-old Amish female presented with 5 day history of bloating and abdominal pain superimposed on a 1 year history of worsening fatigue and intermittent bloody bowel movements. She was found to have a pelvic mass on physical exam. Computed tomography scan of the abdomen and pelvis that demonstrated stricturing of the sigmoid colon, and a large multi-cystic mass in the midline pelvis measuring 12.5 × 9.9 × 11.7 cm. Colonoscopy showed stenosis due to external compression without intraluminal lesion. CEA and CA 125 levels were elevated and CA 19-9 was normal. Exploratory laparotomy was performed with en-bloc resection of a 15 cm mass originating from the sigmoid colon mesentery with several other small tumor deposits throughout the mesentery. Pathology diagnosed primary peritoneal carcinosarcoma Mullerian-type with three positive lymph nodes. Conclusion: Malignant mixed Mullerian tumor (carcinosarcoma) caries a universally grim prognosis. Herein, we report a unique case of primary peritoneal carcinosarcoma and discuss the work-up and surgical management of this rare tumor.

Recurrent midgut volvulus in an 83-year-old female.

We present a rare case of recurrent primary midgut volvulus in an elderly female with an interesting intraoperative finding of an abnormally elongated small bowel mesentery. This patient presented with symptoms of obstruction, including nausea, vomiting and obstipation, similar to previous episodes of volvulus for which she underwent exploratory laparotomies and reduction of the volvulus. We describe a novel use for enteropexy in which we effectively shortened the small bowel mesentery in an effort to eliminate the source of recurrent volvulus. The patient's post-operative course was complicated by prolonged ileus requiring total parenteral nutrition. However, she had not developed signs or symptoms of bowel ischemia or recurrent volvulus at the time of this writing. Our findings suggest that enteropexy is an effective technique for preventing recurrent midgut volvulus primarily caused by abnormally elongated mesentery.

National Comprehensive Cancer Network guidelines compliance of a sarcoma service: A retrospective review.

BACKGROUND: Clinical workup and treatment guidelines have been published by the National Comprehensive Cancer Network (NCCN) to ensure patients are treated uniformly and appropriately. This study sought to retrospectively review patients with a new diagnosis of sarcoma who were treated in a National Cancer Institute (NCI) designated center and determine compliance rates with guidelines for sarcoma. AIM: To evaluate our compliance of NCCN sarcoma guidelines at a major NCI designated center and to report instances of deviation that could be used for future studies to improve patient care. METHODS: Data was collected retrospectively as an internal review and quality assessment of 35 newly diagnosed and treated patients. Demographic data were recorded and information concerning whether patients had appropriate imaging, biopsy and management. Variables of interest were expressed as raw numbers and percentages. RESULTS: Primary site imaging was obtained in 100% of cases. Chest and full-body imaging were obtained in 97% and 100% of indicated cases, respectively. Tissue was obtained preoperatively in 97% of cases. Imaging was reviewed at multidisciplinary Treatment Planning Conference (TPC) in 97% of cases. Pathology was reviewed in 94% of cases in TPC. Both tumor, node, metastasis staging and plan of care were reviewed in 100% of cases in TPC. Treatment guidelines were followed in 94% of cases reviewed. CONCLUSION: This study evaluated the workup and treatment provided by a single NCI designated sarcoma service to a series of patients with pathologies defined with the NCCN sarcoma treatment guidelines. Although adherence to NCCN was reported to be very high future prospective studies are required to investigate whether NCCN guidelines impact patient outcomes.

Do One, Do One, Teach One: Altering the Dogma Using Simulation-Based Training to Maximize Efficiency of Surgical Resident Education.

BACKGROUND: Graduating surgery residents often feel unprepared to practice autonomously in the current era of surgical training. We implemented an integrated simulation curriculum to improve residents' autonomy and increase their confidence to practice independently. In this study, we chose a laparoscopic ventral hernia repair (LVHR) as our pilot operation to test proof of concept and on which we would construct our integrated curriculum. STUDY DESIGN: The curriculum included a web-based cognitive component, inanimate model simulation session with follow-up at 2 weeks and 6 months, and self-confidence questionnaires. Faculty rated each resident's procedure-specific skill by using a modified Global Operative Assessment of Laparoscopic Skills (GOALS) criteria and a task-specific checklist. RESULTS: Thirteen junior residents, 7 senior residents, and 7 faculty surgeons completed the curriculum. Four junior residents (31%) achieved proficiency at their first session, 10 (77%) after the second session (p = 0.031), and 6 (67%) at 6 months (p ≥ 0.99). Three residents regressed and did not maintain proficiency after the second assessment. Performance (GOALS) scores improved (p = 0.0313) at week 2 and were maintained at 6 months (p = 0.5625). Required faculty direction decreased (p = 0.004), and resident confidence in completing the procedure independently improved (p < 0.004) over the 6-month curriculum. CONCLUSIONS: Assessing procedure-specific and global laparoscopic skills through a simulation-based curriculum is feasible and can be used to augment resident training. Our curriculum demonstrated improvement in proficiency and self-confidence while performing an LVHR. Additional study is needed to examine the optimal way to integrate procedure-specific simulation models into training programs.

Genomic regions responsible for seminal and crown root lengths identified by 2D & 3D root system image analysis.

BACKGROUND: Genetic improvement of root system architecture is a promising approach for improved uptake of water and mineral nutrients distributed unevenly in the soil. To identify genomic regions associated with the length of different root types in rice, we quantified root system architecture in a set of 26 chromosome segment substitution lines derived from a cross between lowland indica rice, IR64, and upland tropical japonica rice, Kinandang Patong, (IK-CSSLs), using 2D & 3D root phenotyping platforms. RESULTS: Lengths of seminal and crown roots in the IK-CSSLs grown under hydroponic conditions were measured by 2D image analysis (RootReader2D). Twelve CSSLs showed significantly longer seminal root length than the recurrent parent IR64. Of these, 8 CSSLs also exhibited longer total length of the three longest crown roots compared to IR64. Three-dimensional image analysis (RootReader3D) for these CSSLs grown in gellan gum revealed that only one CSSL, SL1003, showed significantly longer total root length than IR64. To characterize the root morphology of SL1003 under soil conditions, SL1003 was grown in Turface, a soil-like growth media, and roots were quantified using RootReader3D. SL1003 had larger total root length and increased total crown root length than did IR64, although its seminal root length was similar to that of IR64. The larger TRL in SL1003 may be due to increased crown root length. CONCLUSIONS: SL1003 carries an introgression from Kinandang Patong on the long arm of chromosome 1 in the genetic background of IR64. We conclude that this region harbors a QTL controlling crown root elongation.

Epistasis × environment interactions among Arabidopsis thaliana glucosinolate genes impact complex traits and fitness in the field.

Despite the growing number of studies showing that genotype × environment and epistatic interactions control fitness, the influences of epistasis × environment interactions on adaptive trait evolution remain largely uncharacterized. Across three field trials, we quantified aliphatic glucosinolate (GSL) defense chemistry, leaf damage, and relative fitness using mutant lines of Arabidopsis thaliana varying at pairs of causal aliphatic GSL defense genes to test the impact of epistatic and epistasis × environment interactions on adaptive trait variation. We found that aliphatic GSL accumulation was primarily influenced by additive and epistatic genetic variation, leaf damage was primarily influenced by environmental variation and relative fitness was primarily influenced by epistasis and epistasis × environment interactions. Epistasis × environment interactions accounted for up to 48% of the relative fitness variation in the field. At a single field site, the impact of epistasis on relative fitness varied significantly over 2 yr, showing that epistasis × environment interactions within a location can be temporally dynamic. These results suggest that the environmental dependency of epistasis can profoundly influence the response to selection, shaping the adaptive trajectories of natural populations in complex ways, and deserves further consideration in future evolutionary studies.

Evolving technologies for growing, imaging and analyzing 3D root system architecture of crop plants.

A plant's ability to maintain or improve its yield under limiting conditions, such as nutrient deficiency or drought, can be strongly influenced by root system architecture (RSA), the three-dimensional distribution of the different root types in the soil. The ability to image, track and quantify these root system attributes in a dynamic fashion is a useful tool in assessing desirable genetic and physiological root traits. Recent advances in imaging technology and phenotyping software have resulted in substantive progress in describing and quantifying RSA. We have designed a hydroponic growth system which retains the three-dimensional RSA of the plant root system, while allowing for aeration, solution replenishment and the imposition of nutrient treatments, as well as high-quality imaging of the root system. The simplicity and flexibility of the system allows for modifications tailored to the RSA of different crop species and improved throughput. This paper details the recent improvements and innovations in our root growth and imaging system which allows for greater image sensitivity (detection of fine roots and other root details), higher efficiency, and a broad array of growing conditions for plants that more closely mimic those found under field conditions.

Natural genetic variation in Arabidopsis thaliana defense metabolism genes modulates field fitness.

Natural populations persist in complex environments, where biotic stressors, such as pathogen and insect communities, fluctuate temporally and spatially. These shifting biotic pressures generate heterogeneous selective forces that can maintain standing natural variation within a species. To directly test if genes containing causal variation for the Arabidopsis thaliana defensive compounds, glucosinolates (GSL) control field fitness and are therefore subject to natural selection, we conducted a multi-year field trial using lines that vary in only specific causal genes. Interestingly, we found that variation in these naturally polymorphic GSL genes affected fitness in each of our environments but the pattern fluctuated such that highly fit genotypes in one trial displayed lower fitness in another and that no GSL genotype or genotypes consistently out-performed the others. This was true both across locations and within the same location across years. These results indicate that environmental heterogeneity may contribute to the maintenance of GSL variation observed within Arabidopsis thaliana.

Duplicate and conquer: multiple homologs of PHOSPHORUS-STARVATION TOLERANCE1 enhance phosphorus acquisition and sorghum performance on low-phosphorus soils.

Low soil phosphorus (P) availability is a major constraint for crop production in tropical regions. The rice (Oryza sativa) protein kinase, PHOSPHORUS-STARVATION TOLERANCE1 (OsPSTOL1), was previously shown to enhance P acquisition and grain yield in rice under P deficiency. We investigated the role of homologs of OsPSTOL1 in sorghum (Sorghum bicolor) performance under low P. Association mapping was undertaken in two sorghum association panels phenotyped for P uptake, root system morphology and architecture in hydroponics and grain yield and biomass accumulation under low-P conditions, in Brazil and/or in Mali. Root length and root surface area were positively correlated with grain yield under low P in the soil, emphasizing the importance of P acquisition efficiency in sorghum adaptation to low-P availability. SbPSTOL1 alleles reducing root diameter were associated with enhanced P uptake under low P in hydroponics, whereas Sb03g006765 and Sb03g0031680 alleles increasing root surface area also increased grain yield in a low-P soil. SbPSTOL1 genes colocalized with quantitative trait loci for traits underlying root morphology and dry weight accumulation under low P via linkage mapping. Consistent allelic effects for enhanced sorghum performance under low P between association panels, including enhanced grain yield under low P in the soil in Brazil, point toward a relatively stable role for Sb03g006765 across genetic backgrounds and environmental conditions. This study indicates that multiple SbPSTOL1 genes have a more general role in the root system, not only enhancing root morphology traits but also changing root system architecture, which leads to grain yield gain under low-P availability in the soil.