A novel non-invasive radiofrequency dermal heating device for skin tightening of the face and neck

Background: Loose, lax skin is a common cosmetic complaint. Previous non-invasive skin tightening devices had modest efficacy and were associated with pain or downtime. New technologies may allow for effective skin tightening with a series of radiofrequency (RF) treatments with no downtime. Objective: To evaluate the efficacy and safety of a novel bipolar RF device for skin tightening. Methods: Fifteen consecutive female patients were enrolled in the case series; 14 completed the study and were included in the analysis. The device under investigation is a novel, bipolar RF device allowing for achievement and maintenance of optimal dermal temperatures to stimulate collagen remodeling and skin tightening. Patients underwent a series of 4–6 weekly treatments. Three blinded, experienced cosmetic physicians evaluated paired pre-treatment and post-treatment photographs and determined the associated improvement, if any. Results: All patients (14/14) were determined to have a clinical improvement, as the pre-treatment and post-treatment photographs were correctly identified by the evaluators. It was observed that 21% (3/14) of patients had significant improvement, 50% (7/14) had moderate improvement, and 29% (4/14) had mild improvement. No pain, side effects, or adverse events were observed. Conclusions: This novel bipolar RF device represents a safe, effective treatment option for non-invasive skin tightening.     

In vivo animal histology and clinical evaluation of multisource fractional radiofrequency skin resurfacing (FSR) applicator

Abstract

Objective. Acne scars are one of the most difficult disorders to treat in dermatology. The optimal treatment system will provide minimal downtime resurfacing for the epidermis and non-ablative deep volumetric heating for collagen remodeling in the dermis. A novel therapy system (EndyMed Ltd., Cesarea, Israel) uses phase-controlled multi-source radiofrequency (RF) to provide simultaneous one pulse microfractional resurfacing with simultaneous volumetric skin tightening. Methods. The study included 26 subjects (Fitzpatrick's skin type 2–5) with moderate to severe wrinkles and 4 subjects with depressed acne scars. Treatment was repeated each month up to a total of three treatment sessions. Patients’ photographs were graded according to accepted scales by two uninvolved blinded evaluators. Results. Significant reduction in the depth of wrinkles and acne scars was noted 4 weeks after therapy with further improvement at the 3-month follow-up. Conclusion. Our data show the histological impact and clinical beneficial effects of simultaneous RF fractional microablation and volumetric deep dermal heating for the treatment of wrinkles and acne scars.     

A Clinical and Biochemical Evaluation of a Temperature-Controlled Continuous Non-Invasive Radiofrequency Device for the Treatment of Melasma

BackgroundMelasma shows characteristic histological features of photoaged skin.ObjectiveWe evaluated the effect of dermal rejuvenation using a temperature-controlled continuous non-invasive radiofrequency (RF) device on melasma.MethodsContinuous skin heating at the temperature of 43°C for 20 minutes was performed in ten subjects with melasma who underwent 3 tri-weekly RF sessions. Pigmentation was evaluated with Mexameter® and investigator’s global assessment (IGA). Immunohistochemical staining and image analysis was performed to evaluate biopsies from melasma skin before and after the treatment.ResultsThe lesional melanin index was decreased by 13.7% at week 9. IGA score was improved from 3.50 at baseline to 2.95 at week 9. No significant adverse event was reported. Histologic analysis revealed reduced melanin and increased collagen density and thickness. The expression of procollagen-1 and type IV collagen was increased after the treatment. The number of p16^INK4A-positive senescent fibroblasts was reduced after the treatment, while the expression of heat shock protein 70 and 90 was increased. Stromal derived factor-1, a senescence-associated anti-melanogenic factor secreted from the fibroblasts, was up-regulated after the treatment, while the level of c-kit was not changed.ConclusionThermal skin stimulation by the temperature-controlled continuous RF device improved melasma through dermal rejuvenation.     

Combination of microneedle radiofrequency (RF), fractional RF skin resurfacing and multi-source non-ablative skin tightening for minimal-downtime,full-face skin rejuvenation

Background: In the recent years, there is a growth in demand for radiofrequency (RF)-based procedures to improve skin texture, laxity and contour. The new generation of systems allow non-invasive and fractional resurfacing treatments on one platform. Objective: The aim of this study was to evaluate the safety and efficacy of a new treatment protocol using a multisource RF, combining 3 different modalities in each patient: [1] non-ablative RF skin tightening, [2] fractional skin resurfacing, and [3] microneedling RF for non-ablative coagulation and collagen remodelling. Methods: 14 subjects were enrolled in this study using EndyMed PRO^? platform. Each patient had 8 non-ablative treatments and 4 fractional treatments (fractional skin resurfacing and Intensif). Results: The global aesthetic score was used to evaluate improvement. All patients had improvement in skin appearance. About 43% had excellent or very good improvement above 50%, 18% had good improvement between 25 and 50%, and the rest 39% had a mild improvement of < 25%. Downtime was minimal and no adverse effect was reported. Conclusions: Our data show significant improvement of skin texture, skin laxity and wrinkle reduction achieved using RF treatment platform.     

A pilot study of the efficacy of the POLARGEN® ultrahigh-frequency electric field (40.68 MHz) radiofrequency device in the treatment of facial contouring

Background: Various radiofrequency (RF) devices are used to treat skin laxity and face contouring, but few studies have examined ultrahigh-frequency (UHF) electric field (40.68 MHz) RF devices. Objective: To evaluate the efficacy and safety of a UHF electric field (40.68 MHz) RF device for skin tightening and face contouring. Methods: Ten patients each underwent four sessions of UHF electric field RF device treatment at 2-week intervals. Clinical improvement was evaluated with the patient satisfaction score using a six-point scale, and clinical photographs taken at every visit and 2 months after the RF treatment were assessed. Skin biopsies were obtained from one patient before the first treatment and immediately after the last treatment. Adverse reactions were recorded at every follow-up visit. Results: All patients were women with a mean age of 51.7 ± 7.2 years. The mean satisfaction score was 4.5 ± 0.9 immediately after the last treatment session. Cheek, jawline, and neck enhancement and tightening were apparent in all patients. Side effects were minimal, and there were no burns or major complications. Conclusions: The UHF electric field RF device was effective for skin tightening and facial contouring, without significant adverse reactions.     

Visualizing radiofrequency-skin interaction using multiphoton microscopy in vivo

Background

Redundant skin laxity is a major feature of aging. Recently, radiofrequency has been introduced for nonablative tissue tightening by volumetric heating of the deep dermis. Despite the wide range of application based on this therapy, the effect of this technique on tissue and the subsequent tissue remodeling have not been investigated in detail.

Objective

Our objective is to evaluate the potential of non-linear optics, including multiphoton autofluorescence and second harmonic generation (SHG) microscopy, as a non-invasive imaging modality for the real-time study of radiofrequency-tissue interaction.

Methods

Electro-optical synergy device (ELOS) was used as the radiofrequency source in this study. The back skin of nude mouse was irradiated with radiofrequency at different passes. We evaluated the effect on skin immediately and 1 month after treatment with multiphoton microscopy.

Results

Corresponding histology was performed for comparison. We found that SHG is negatively correlated to radiofrequency passes, which means that collagen structural disruption happens immediately after thermal damage. After 1 month of collagen remodeling, SHG signals increased above baseline, indicating that collagen regeneration has occurred. Our findings may explain mechanism of nonablative skin tightening and were supported by histological examinations.

Conclusions

Our work showed that monitoring the dermal heating status of RF and following up the detailed process of tissue reaction can be imaged and quantified with multiphoton microscopy non-invasively in vivo.     

Clinical and histopathological results following TriPollar™ radiofrequency skin treatments

Introduction: Skin laxity, wrinkles and cellulite are common aesthetic problems associated with the aging process. These symptoms are due to the weakening and thinning of dermal connective tissue and the enlargement of hypodermal fat cells. The aim of this study was to evaluate the safety and efficacy of the TriPollar RF technology in reducing fat and collagen regeneration. Methods: Twelve healthy patients underwent weekly treatments on different body sites using the TriPollar technology. Treatment areas were photographed and measured and patient satisfaction was monitored. One abdominal patient consented to a series of TriPollar treatments prior to her scheduled abdominoplasty. A controlled histopathology analysis was performed on skin samples taken during the abdominoplasty procedure. Results: Histopatho-logical examination revealed marked differences between treated and non-treated abdominal skin areas. An increase of 49% in dermal thickness, focal thickening of collagen fibers and focal shrinkage of fat cells was shown following TriPollar treatments. Average patient satisfaction indicated clear satisfaction with the clinical results achieved. Conclusion: The TriPollar is a safe and effective non-invasive technology leading to skin tightening and body shaping. Histology results indicate changes at the dermal and fat layers following TriPollar treatments resulting in increased collagen regeneration and stimulated fat metabolism.     

Painless,safe, and efficacious noninvasive skin tightening,body contouring,and cellulite reduction using multisource 3DEEP radiofrequency

In the last decade, Radiofrequency (RF) energy has proven to be safe and highly efficacious for face and neck skin tightening, body contouring, and cellulite reduction. In contrast to first‐generation Monopolar/Bipolar and “X ‐Polar” RF systems which use one RF generator connected to one or more skin electrodes, multisource radiofrequency devices use six independent RF generators allowing efficient dermal heating to 52–55 °C, with no pain or risk of other side effects. In this review, the basic science and clinical results of body contouring and cellulite treatment using multisource radiofrequency system (Endymed PRO, Endymed, Cesarea, Israel) will be discussed and analyzed.     

Comparison of the effects of carboxytherapy and radiofrequency on skin rejuvenation

Background: Carboxytherapy (CA) refers to the cutaneous and subcutaneous administration of CO₂ for therapeutic purposes. Radiofrequency (RF) is a method that uses electric current for heating layers of the skin. Both techniques are indicated for the treatment of skin laxity. Objective: The aim of this study was to compare the effects of CA and RF on human skin. Methods: After eight patients underwent abdominoplasty, each of them received a single treatment of CA and a single treatment of RF on the right and left infra-umbilical regions, respectively. In the infra-umbilical region, CA was performed on the right and RF was performed on the left side. Untreated skin was used as a control. The sample collection period lasted 120 days. CA was administered at a velocity of 40 mL/min, and the total quantity of CO₂ infused was approximately 20 mL. RF was carried out at a temperature higher than 40°C on the epidermis for 5 min. Results: CA and RF led to collagen remodeling; however, this result was more evident and lasted longer with RF. With CA an increase in elastic fibers was observed, whereas with RF no alteration was observed. Conclusion: Our results suggest that RF is more efficient than CA in stimulating collagen synthesis.     

Combined treatment for skin laxity of the aging face with monopolar radiofrequency and intense focused ultrasound in Korean subjects

Background: Although various minimal invasive approaches are available for aging skin laxity, they alone may not lead to notably satisfactory results. Objective: To evaluate the effectiveness and safety of combination regimen with monopolar radiofrequency (MRF) and intense-focused ultrasound (IFUS) in facial lifting and tightening. Methods: Twenty-two Korean participants with aging face received a sequential single session of MRF and IFUS treatment. Objective and subjective assessments for improvement were performed at the 20-week post-treatment. Safety profiles were also recorded, and skin biopsies were taken at baseline and follow-up visit. Results: Based on the objective assessment for the overall facial skin tightening and laxity, 19 patients (90%) demonstrated “moderate” or better improvements (more than 25%) compared with baseline. Specifically, improvements of skin laxity and sagging, and droopy jaw line were more noticeable compared with that of superficial skin texture (P < 0.05). Subjective satisfactions were generally consistent with objective findings, and no serious adverse effect was observed. Histologic evaluation showed increased dermal collagen fibers throughout the dermis after treatments (P < 0.05). Conclusion: Combination treatment of MRF and IFUS has cumulative benefits for skin lifting and tightening with satisfactory safety profiles in Asian subjects.     

Comparative histometric analysis of the effects of high-intensity focused ultrasound and radiofrequency on skin

Introduction: High-intensity focused ultrasound (HIFU) and radiofrequency (RF) are used for non-invasive skin tightening. Neocollagenesis and neoelastogenesis have been reported to have a mechanism of controlled thermal injury. Objective: To compare neocollagenesis and neoelastogenesis in each layer of the dermis after each session of HIFU and monopolar RF. Methods: We analyzed the area fraction of collagen and elastic fibers using the Masson's Trichrome and Victoria blue special stains, respectively, before and after 2 months of treatments. Histometric analyses were performed in each layer of the dermis, including the papillary dermis, and upper, mid, and deep reticular dermis. Results: Monopolar RF led to neocollagenesis in the papillary dermis, and upper, mid, and deep reticular dermis, and neoelastogenesis in the papillary dermis, and upper and mid reticular dermis. HIFU led to neocollagenesis in the mid and deep reticular dermis and neoelastogenesis in the deep reticular dermis. Among these treatment methods, HIFU showed the highest level of neocollagenesis and neoelastogenesis in the deep reticular dermis. Conclusions: HIFU affects deep tissues and impacts focal regions. Monopolar RF also affects deep tissues, but impacts diffuse regions. We believe these data provide further insight into effective skin tightening.     

Stimulation of collagen and elastin production in-vivo using 1,540 nm Er:Glass laser: assessment of safety and efficacy

ABSTRACT

Introduction: Induction of collagen and elastin remodeling in the human skin can be achieved by non-ablative fractional laser (NAFXL) and ablative fractional laser (AFXL). Our objective was to compare the safety, efficacy, tolerability, and ability to induce collagen and elastin remodeling of NAFXL versus AFXL in a series of treatments over time.

Materials and Methods: In this prospective, proof of principle, single-case study, the safety, tolerability and efficacy of the laser systems were assessed via histopathology and clinical evaluations including photographs. Optical biopsies by means of multiphoton tomography (MPT) were used to evaluate the induction of collagen and elastin remodeling.

Results: Treatments by both NAFXL and AFXL were well tolerated. The NAFXL system was found to be less painful and resulted in a shorter down- and healing times. MPT findings showed the superior capability of the AFXL procedure to induce collagen; on the other hand, elastin induction was more pronounced after NAFXL treatments.

Conclusions: While NAFXL is as effective and safe as the traditional AFXL, it is better tolerated and has a shorter downtime. Serial optical biopsies over time over time can be a useful tool to assess the induction of collagen and elastin remodeling in the human skin.     

强脉冲光及射频对BALB/c小鼠皮肤胶原的影响

【摘要】 目的 探讨强脉冲光和射频对BALB/c小鼠皮肤的外观不良反应、组织病理、真皮厚度变化及胶原含量的影响。方法 将BALB/c小鼠随机分为强脉冲光照射组（IPL组）、射频照射组（RF组）、强脉冲光+射频联合照射组（IPL联合RF组）及正常对照组。以强脉冲光和射频处理BALB/c小鼠皮肤,于各时间点观察各组小鼠皮肤外观局部不良反应发生率,取小鼠皮肤行HE染色 观察各组皮肤组织病理及真皮厚度变化,Masson染色分析各组小鼠皮肤组织胶原纤维的表达。 结果 强脉冲光和射频照射后小鼠皮肤局部无不良反应,处理8周后, IPL组、RF组及IPL联合RF组的真皮层均较正常对照组渐进性增厚趋势,胶原纤维增厚、增加,排列致密,细胞间基质逐渐增加,IPL联合RF组较IPL组、RF组更为明显,差异有统计学意义（P ＜ 0.05）。表皮未见明显增厚。 结论 强脉冲光和射频均可刺激真皮胶原纤维增加,联合强脉冲光和射频技术可以增强对胶原纤维的生物刺激作用。     

<Emphasis Type="Italic">Ex-vivo</Emphasis> study of hybrid energy technology using a human skin model

Background

More aging adults and the social acceptance of aesthetic treatments have increased the demand for minimally invasive aesthetic treatments. Skin resurfacing is very effective at improving aging symptoms, including wrinkles and skin imperfections. Following the negative effects of full skin resurfacing, in addition to a very long downtime, fractional lasers and fractional radiofrequency (RF) technologies were introduced, since gaining popularity. Their efficacy, along with minimal downtime, has enabled an effective and safer treatment. A novel technology based on fractional Hybrid Energy? (HE), combines RF and an additional electrical energy for enhancing the thermal effect.

Objective

This study evaluated the morphological and histological effects of the new HE technology on epidermal and dermal skin layers, using an ex-vivo human skin model.

Methods

Human skin samples were collected and treated ex-vivo with the HE applicator. The effect was evaluated by skin histology and quantitative analysis by assays of collagen fibers, elastin and glycosaminoglycan (GAGs) dosages, reflecting the hyaluronic acid content, in addition to epidermal mitotic index evaluation.

Results

Histology demonstrated immediate and long-term HE effects on both epidermal and dermal skin layers with a direct correlation between the treatment parameters and effects. Results demonstrated a significant increase of the epidermal mitotic index, significant dermal collagen remodeling and significant increases in both epidermal and dermal GAGs.

Conclusions

HE technology significantly affected collagen remodeling and an increase in mid to deep dermis GAGs in addition to epidermal mitotic index, resulting in long term structural and biochemical dermal and epidermal improvement.

     

Histological evaluation of dermal tissue remodeling with the 1444‐nm neodymium:yttrium–aluminum–garnet laser in in vivo model

Laser lipolysis has a skin tightening effect by heating the deep dermis, in addition to the removal of fat tissues. The 1444‐nm neodymium:yttrium–aluminum–garnet (Nd:YAG) laser has been expected to be more effective and safe for laser lipolysis, due to higher affinity to fat and water, than 1064‐nm and 1320‐nm wavelengths. The purpose of this study was to evaluate the skin tightening effect of the 1444‐nm Nd:YAG laser through in vivo guinea pig models. The 1444‐nm Nd:YAG laser was used to irradiate shaved dorsal skin of the guinea pigs and compared with controls (no power, only tunneling). Immediately, 1 week, 1 month and 3 months after laser administration, full‐thickness skins were harvested and to evaluate dermal thickness, collagen organization, fibroblast proliferation, and intensity of elastic fibers and mucopolysaccharides, using hematoxylin–eosin, Masson‐trichrome, Verhoeff's stain and Alcian blue stain. Dermal thickness showed an increase with time in all groups. In collagen organization, fibroblast proliferation, and intensity of elastic fibers and mucopolysaccharides, the treatment groups were higher than those of the control group, overall. Our study showed that the 1444‐nm Nd:YAG laser appeared to be effective for the skin tightening effect in in vivo guinea pig models. The 1444‐nm Nd:YAG laser can be used for skin tightening, as well as reduction of fat tissues.     

UVB irradiation stimulates deposition of new elastic fibers by modified epithelial cells surrounding the hair follicles and sebaceous glands in mice

UVB irradiation stimulates the synthesis of elastin in the skin of humans and experimental animals. In this study we localized the site and the cells that are responsible for the synthesis of murine dermal elastic fibers. SKH-1 hairless mice were irradiated with UVB and the skin removed for light microscopy, electron microscopy, in situ hybridization, immunohistochemistry, and biochemical studies. In response to chronic low doses of UVB there was an initial moderate increase in tropoelastin mRNA in the papillary dermis. By contrast, there was a continuous marked elevation of collagen alpha1(I) message localizing to sites of inflammatory cell influx throughout the upper and lower dermis. After 25 wk of UV irradiation there was a 2-fold increase in skin elastin, yet total collagen remained unchanged. Serial desmosine analysis from en face sections indicated the increase in elastin content was due to dermal elastic fibers, an increase in the size and number of the dermal cysts, and an increase in subpanniculus elastic fibers. Elastin stains of en face sections suggested that the elastic fibers in the upper dermis were exclusively derived from cells lining the epithelial root sheath and sebaceous glands. In response to UV irradiation, the elastic fibers increased in number and size, wrapping around these structures and aligning in both directions as long fibers parallel to the body axis. Electron micrographs indicated that modified epithelial cells in close proximity to the flattened epithelial cells that encircled the root sheath and sebaceous glands were the source of the elastic fibers.     

Histological evidence for skin rejuvenation using a combination of pneumatic energy,broadband light,and growth factor therapy

Abstract

Background and objective: A variety of laser or light-based devices have been developed for skin rejuvenation. This study evaluates the efficacy (at the microscopic level) of a combination of pneumatic energy, broadband light, and profusion tip-delivered epidermal growth factor (EGF). Methods: Healthy adult Japanese volunteers were recruited for this study. The posterior parts of the left and right arms were treated with a device that combines pneumatic energy and broadband light (Isolaz device). The left arms were also treated with EGF through a tip. Each subject received four treatments at 10-day intervals. Biopsy specimens obtained 3 weeks after the second treatment and 3 weeks after the fourth treatment were examined for histological study. Results: After two treatments, elastin fibers and fibroblasts in the dermal papillary layers of the left arms were increased compared to the right arms. A mean of 173.9 cells positive for proliferating cell nuclear antibody (PCNA) were observed on the left arm compared to 101.0 on the right arm. After the fourth treatment, angiogenesis and increased collagen fibers were observed in the dermal papillary layers of both arms. Conclusion: Four treatments with the addition of the profusion tip appear to hasten new collagen and elastin fiber formation, and the increase of PCNA positive cells so that dermal remodeling begins at an earlier stage than with the Isolaz alone.     

Comparison of effect between high intense focused ultrasound devices for facial tightening: Evaluator-blinded,split-face study

Background: Various high intense focused ultrasound (HIFU) devices have been introduced in recent years for improving skin laxity, with satisfactory results. However, there is no comparative study on the efficacy and safety of available HIFU devices. Objective: To compare the efficacy and safety of two HIFU devices for facial skin tightening and subsequently, to validate the quantitative assessment. Methods and materials: We performed a split-face comparative study in 20 Korean patients. Two different HIFU devices were used on each side of the face. Patients received one treatment session on the same number of coagulative zones. Patient assessments were recorded. Three blinded clinicians evaluated paired pretreatment and post-treatment photographs. Quantitative assessment using a fixed point as well as a variable point was additionally performed for objective evaluation. Results: Qualitative assessments of both HIFU devices conducted by both clinicians and patients generally showed mild to moderate improvement, similar to previous studies. The two devices had similar efficacy in blinded clinician and quantitative assessment, although there were some differences in patient satisfaction and degree of pain. There was a correlation between clinician qualitative scores and quantitative values, which suggests successful skin tightening. Conclusion: To the author's knowledge, both HIFU devices tested can be used safely and effectively for facial tightening.     

Complementary clinical effects of topical tightening treatment in conjunction with a radiofrequency procedure

Abstract

Background: Skin laxity and cellulite on the buttocks and thighs are two common cosmetic concerns. Skin tightening with radiofrequency (RF) devices has become increasingly popular. Objective: The purpose of this study is to evaluate the efficacy and safety of a topical skin laxity tightening agent when used in combination with an RF device. Methods: A double-blinded, randomized clinical trial enrolled twenty females with mild-to-moderate skin laxity on the posterior thighs/buttocks. Each subject underwent two monthly treatments with an RF source (Alma Accent) to both legs. Subjects were then randomized to apply a topical agent (Skinceuticals Body Tightening Concentrate) twice daily to only one designated thigh/buttock throughout the eight-week duration of the study. All subjects were evaluated for improvement in lifting, skin tone, radiance, firmness/tightness, skin texture, and overall appearance based on photographic evaluation by blinded investigators at 12 weeks following the final RF treatment. Results: A statistically significant improvement was found in the overall appearance on both sides treated with the RF device when compared to baseline. However, the area treated with the topical agent showed a statistically significantly greater degree of improvement than the side where no topical agent was applied. No adverse effects were reported. Conclusion: The use of a novel skin tightening agent used after RF procedures is both safe and effective for treatment of skin laxity on the buttocks and thighs. Combined therapy leads to a better result.     

Effect of mesotherapy with nanochip in the treatment of facial rejuvenation

ABSTRACT

Objective: To observe the clinical effect of mesotherapy with nanochip for facial rejuvenation.

Methods: 24 volunteers with aging skin were treated with a polycomponent formulation – NCTF® BOOST 135 HA for 5 times (once weekly for 3 times and successively biweekly for 2 times). Photographs were taken by VISIA at baseline, and after 1, 4, 10 weeks, while global scores for photoaging (GSP), improvement scores, volunteers’ satisfaction, parameters describing the properties of the skin, and adverse effects were assessed during each follow-up period.

Results: Total 20 volunteers completed the treatment. Evaluation of the whole face showed that GSP, skin texture (ophthalmic wrinkles, dermal thickness, and intensity of collagen fibers of skin), and skin brightness (Lab value) significantly improved at 4 weeks compared to baseline, while the difference between 4 and 10 weeks was not statistically significant. No evident improvement was observed in pigmented spots, telangiectasia, skin tightening, trans-epidermal water loss (TEWL), and skin hydration. Slight erythema, pain was the most common side effect.

Conclusion: Mesotherapy with nanochip can improve skin texture and brightness, but the effect is not permanent. It is recommended that the treatment be used as a complementary method for patients with facial rejuvenation needs.